National Library of Energy BETA

Sample records for ionization mass spectrometry

  1. Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

    2014-06-13

    Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

  2. Atmospheric Ionization Mass Spectrometry Capabilities at Sandia...

    Office of Scientific and Technical Information (OSTI)

    Mass Spectrometry Capabilities at Sandia National Labs. Citation Details In-Document Search Title: Atmospheric Ionization Mass Spectrometry Capabilities at Sandia National Labs. ...

  3. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOE Patents [OSTI]

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  4. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  5. Analysis of perchlorate in groundwater by electrospray ionization mass spectrometry/mass spectrometry

    SciTech Connect (OSTI)

    Koester, C.J.; Beller, H.R.; Halden, R.U.

    2000-05-01

    An electrospray ionization mass spectrometry/mass spectrometry (ESI/MS/MS) method was developed to measure part-per-billion ({micro}g/L) concentrations of perchlorate in groundwater. Selective and sensitive perchlorate detection was achieved by operating the mass spectrometer in the negative ionization mode and by using MS/MS to monitor the CIO{sub 4}{sup {minus}} to ClO{sub 3}{sup {minus}} transition. The method of standard additions was used to address the considerable signal suppression caused by anions that are typically present in groundwater, such as bicarbonate and sulfate. ESI-MS/MS analysis was rapid, accurate, reproducible, and provided a detection limit of 0.5 {micro}g/L perchlorate in groundwater. Accuracy and precision of the ESI/MS/MS method were assessed by analyzing performance evaluation samples in a groundwater matrix and by comparing ion chromatography (IC) and ESI/MS/MS results for local groundwater samples. Results for the performance evaluation samples differed from the certified values by 4--13%, and precision ranged from 3 to 10% (relative standard deviation). The IC and ESI/MS/MS results were statistically indistinguishable for perchlorate concentrations above the detection limits of both methods.

  6. Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2012-10-30

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  7. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2014-08-19

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  8. Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2013-07-16

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  9. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, In vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2011-11-29

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation (LA) with electrospray ionization (ESI).

  10. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2013-07-16

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  11. Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2011-06-21

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  12. ASSESSMENT OF MARKER PROTEINS IDENTIFIED IN WHOLE CELL EXTRACTS FOR BACTERIAL SPECIATION USING LIQUID CHROMATOGRAPHY ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMETRY

    SciTech Connect (OSTI)

    Kooken, Jennifer M.; Fox, Karen F.; Fox, Alvin; Wunschel, David S.

    2014-02-02

    ASSESSMENT OF MARKER PROTEINS IDENTIFIED IN WHOLE CELL EXTRACTS FOR BACTERIAL SPECIATION USING LIQUID CHROMATOGRAPHY ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMETRY

  13. Laser-Induced Ionization Efficiency Enhancement On A Filament For Thermal Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Siegfried, M.

    2015-10-14

    The evaluation of trace Uranium and Plutonium isotope ratios for nanogram to femtogram material quantities is a vital tool for nuclear counter-proliferation and safeguard activities. Thermal Ionization Mass Spectrometry (TIMS) is generally accepted as the state of the art technology for highly accurate and ultra-trace measurements of these actinide ratios. However, the very low TIMS ionization yield (typically less than 1%) leaves much room for improvement. Enhanced ionization of Nd and Sm from a TIMS filament was demonstrated using wavelength resonance with a nanosecond (pulse width) laser operating at 10 Hz when light was directed toward the filament.1 For this study, femtosecond and picosecond laser capabilities were to be employed to study the dissociation and ionization mechanisms of actinides/lanthanides and measure the enhanced ionization of the metal of interest. Since the underlying chemistry of the actinide/lanthanide carbides produced and dissociated on a TIMS filament is not well understood, the experimental parameters affecting the photodissociation and photoionization with one and two laser beams were to be investigated.

  14. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    SciTech Connect (OSTI)

    Perdian, David C.

    2009-08-19

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  15. Spatially resolved thermal desorption/ionization coupled with mass spectrometry

    DOE Patents [OSTI]

    Jesse, Stephen; Van Berkel, Gary J; Ovchinnikova, Olga S

    2013-02-26

    A system and method for sub-micron analysis of a chemical composition of a specimen are described. The method includes providing a specimen for evaluation and a thermal desorption probe, thermally desorbing an analyte from a target site of said specimen using the thermally active tip to form a gaseous analyte, ionizing the gaseous analyte to form an ionized analyte, and analyzing a chemical composition of the ionized analyte. The thermally desorbing step can include heating said thermally active tip to above 200.degree. C., and positioning the target site and the thermally active tip such that the heating step forms the gaseous analyte. The thermal desorption probe can include a thermally active tip extending from a cantilever body and an apex of the thermally active tip can have a radius of 250 nm or less.

  16. Plume collimation for laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  17. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    SciTech Connect (OSTI)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.

    1996-02-01

    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  18. An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Van Berkel, Gary J.; Kertesz, Vilmos

    2015-01-01

    RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creatingmore » a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.« less

  19. An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Van Berkel, Gary J.; Kertesz, Vilmos

    2015-01-01

    RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creating a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.

  20. Elemental and isotopic analysis of inorganic salts by laser desorption ionization mass spectrometry

    SciTech Connect (OSTI)

    Jayasekharan, T.; Sahoo, N. K.

    2013-02-05

    Laser desorption ionization mass spectrometry is applied for the analysis of elements as well as their isotopic composition in different inorganic salts. At very low laser energies the inorganic ions are desorbed and ionized from the thin layer of the sample surface. The naturally occurring isotopes of alkali and silver ions are resolved using time of flight mass spectrometer. Further increase in laser energy shows the appearance of Al, Cr, and Fe ions in the mass spectra. This indicates the penetration laser beam beyond the sample surface leading to the ablation of sample target at higher energies. The simultaneous appearance of atomic ions from the sample target at relatively higher laser energies hampers the unambiguous identification of amino acid residues from the biomolecular ions in MALDI-MS.

  1. Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

    SciTech Connect (OSTI)

    Isselhardt, B H

    2011-09-06

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of {sup 235}U/{sup 238}U ratios to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a 3-color, 3-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from >10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variation in laser parameters on the measured isotope ratio. This work demonstrates that RIMS can be used for the robust measurement of uranium isotope ratios.

  2. Shotgun Approach for Quantitative Imaging of Phospholipids Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Lanekoff, Ingela T.; Thomas, Mathew; Laskin, Julia

    2014-02-04

    Mass spectrometry imaging (MSI) has been extensively used for determining spatial distributions of molecules in biological samples, and there is increasing interest in using MSI for quantification. Nanospray desorption electrospray ionization, or nano-DESI, is an ambient MSI technique where a solvent is used for localized extraction of molecules followed by nanoelectrospray ionization. Doping the nano-DESI solvent with carefully selected standards enables online quantification during MSI experiments. In this proof-of-principle study, we demonstrate this quantification approach can be extended to provide shotgun-like quantification of phospholipids in thin brain tissue sections. Specifically, two phosphatidylcholine (PC) standards were added to the nano-DESI solvent for simultaneous imaging and quantification of 22 PC species observed in nano-DESI MSI. Furthermore, by combining the quantitative data obtained in the individual pixels, we demonstrate quantification of these PC species in seven different regions of a rat brain tissue section.

  3. Imaging of Lipids and Metabolites Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Lanekoff, Ingela; Laskin, Julia

    2015-01-17

    In recent years, mass spectroscopy imaging (MSI) has emerged as a foundational technique in metabolomics and drug screening providing deeper understanding of complex mechanistic pathways within biochemical systems and biological organisms. We have been invited to contribute a chapter to a new Springer series volume, entitled Mass Spectrometry Imaging of Small Molecules. The volume is planned for the highly successful lab protocol series Methods in Molecular Biology, published by Humana Press, USA. The volume is aimed to equip readers with step-by-step mass spectrometric imaging protocols and bring rapidly maturing methods of MS imaging to life science researchers. The chapter will provide a detailed protocol of ambient MSI by use of nanospray desorption electrospray ionization.

  4. Controlled-Resonant Surface Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    SciTech Connect (OSTI)

    Lorenz, Matthias; Ovchinnikova, Olga S; Kertesz, Vilmos; Van Berkel, Gary J

    2014-01-01

    This paper reports on the advancement of a controlled-resonance surface tapping-mode single capillary liquid junction extraction/ESI emitter for mass spectrometry imaging. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to spot sample, lane scan and chemically image in an automated and controlled fashion were demonstrated. Rapid, automated spot sampling was demonstrated for a variety of compound types including the cationic dye basic blue 7, the oligosaccharide cellopentaose, and the protein equine heart cytochrome c. The system was used for lane scanning and chemical imaging of the cationic dye crystal violet in inked lines on glass and for lipid distributions in mouse brain thin tissue sections. Imaging of the lipids in mouse brain tissue under optimized conditions provided a spatial resolution of approximately 35 m based on the ability to distinguish between features observed both in the optical and mass spectral chemical images. The sampling spatial resolution of this system was comparable to the best resolution that has been reported for other types of atmospheric pressure liquid extraction-based surface sampling/ionization techniques used for mass spectrometry imaging.

  5. Membrane-Based Emitter for Coupling Microfluidics with Ultrasensitive Nanoelectrospray Ionization-Mass Spectrometry

    SciTech Connect (OSTI)

    Sun, Xuefei; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

    2011-06-09

    An integrated poly(dimethylsiloxane) (PDMS) membrane-based microfluidic emitter for high performance nanoelectrospray ionization-mass spectrometry (nanoESI-MS) has been fabricated and evaluated. The ~100-?m-thick emitter was created by cutting a PDMS membrane that protrudes beyond the bulk substrate. The reduced surface area at the emitter enhances the electric field and reduces wetting of the surface by the electrospray solvent. As such, the emitter provides highly stable electrospray at flow rates as low as 10 nL/min, and is compatible with electrospray solvents containing a large organic component (e.g., 90% methanol). This approach enables facile emitter construction, and provides excellent stability, reproducibility and sensitivity, as well as compatibility with multilayer soft lithography.

  6. Development of matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) for plant metabolite analysis

    SciTech Connect (OSTI)

    Korte, Andrew R

    2014-12-01

    This thesis presents efforts to improve the methodology of matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) as a method for analysis of metabolites from plant tissue samples. The first chapter consists of a general introduction to the technique of MALDI-MSI, and the sixth and final chapter provides a brief summary and an outlook on future work.

  7. Laser vaporization/ionization interface for coupling microscale separation techniques with mass spectrometry

    DOE Patents [OSTI]

    Yeung, E.S.; Chang, Y.C.

    1999-06-29

    The present invention provides a laser-induced vaporization and ionization interface for directly coupling microscale separation processes to a mass spectrometer. Vaporization and ionization of the separated analytes are facilitated by the addition of a light-absorbing component to the separation buffer or solvent. 8 figs.

  8. Laser vaporization/ionization interface for coupling microscale separation techniques with mass spectrometry

    DOE Patents [OSTI]

    Yeung, Edward S.; Chang, Yu-chen

    1999-06-29

    The present invention provides a laser-induced vaporization and ionization interface for directly coupling microscale separation processes to a mass spectrometer. Vaporization and ionization of the separated analytes are facilitated by the addition of a light-absorbing component to the separation buffer or solvent.

  9. Imaging Nicotine in Rat Brain Tissue by Use of Nanospray Desorption Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Lanekoff, Ingela T.; Thomas, Mathew; Carson, James P.; Smith, Jordan N.; Timchalk, Charles; Laskin, Julia

    2013-01-15

    Imaging mass spectrometry offers simultaneous detection of drugs, drug metabolites and endogenous substances in a single experiment. This is important when evaluating effects of a drug on a complex organ system such as the brain, where there is a need to understand how regional drug distribution impacts function. Nicotine is an addictive drug and its action in the brain is of high interest. Here we use nanospray desorption electrospray ionization, nano-DESI, imaging to discover the localization of nicotine in rat brain tissue after in vivo administration of nicotine. Nano-DESI is a new ambient technique that enables spatially-resolved analysis of tissue samples without special sample pretreatment. We demonstrate high sensitivity of nano-DESI imaging that enables detection of only 0.7 fmole nicotine per pixel in the complex brain matrix. Furthermore, by adding deuterated nicotine to the solvent, we examined how matrix effects, ion suppression, and normalization affect the observed nicotine distribution. Finally, we provide preliminary results suggesting that nicotine localizes to the hippocampal substructure called dentate gyrus.

  10. Wall loss of atomic nitrogen determined by ionization threshold mass spectrometry

    SciTech Connect (OSTI)

    Sode, M. Schwarz-Selinger, T.; Jacob, W.; Kersten, H.

    2014-11-21

    In the afterglow of an inductively coupled N{sub 2} plasma, relative N atom densities are measured by ionization threshold mass spectrometry as a function of time in order to determine the wall loss time t{sub wN} from the exponential decay curves. The procedure is performed with two mass spectrometers on different positions in the plasma chamber. t{sub wN} is determined for various pressures, i.e., for 3.0, 5.0, 7.5, and 10?Pa. For this conditions also the internal plasma parameters electron density n{sub e} and electron temperature T{sub e} are determined with the Langmuir probe and the rotational temperature T{sub rot}{sup N{sub 2}} of N{sub 2} is determined with the optical emission spectroscopy. For T{sub rot}{sup N{sub 2}}, a procedure is presented to evaluate the spectrum of the transition ?{sup ?}=0??{sup ?}=2 of the second positive system (C{sup 3}?{sub u}?B{sup 3}?{sub g}) of N{sub 2}. With this method, a gas temperature of 610?K is determined. For both mass spectrometers, an increase of the wall loss times of atomic nitrogen with increasing pressure is observed. The wall loss time measured with the first mass spectrometer in the radial center of the cylindrical plasma vessel increases linearly from 0.31?ms for 3?Pa to 0.82?ms for 10?Pa. The wall loss time measured with the second mass spectrometer (further away from the discharge) is about 4 times higher. A model is applied to describe the measured t{sub wN.} The main loss mechanism of atomic nitrogen for the considered pressure is diffusion to the wall. The surface loss probability ?{sub N} of atomic nitrogen on stainless steel was derived from t{sub wN} and is found to be 1 for the present conditions. The difference in wall loss times measured with the mass spectrometers on different positions in the plasma chamber is attributed to the different diffusion lengths.

  11. Fully Automated Laser Ablation Liquid Capture Sample Analysis using NanoElectrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Lorenz, Matthias; Ovchinnikova, Olga S; Van Berkel, Gary J

    2014-01-01

    RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system. RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant

  12. Chemical Characterization of Crude Petroleum Using Nanospray Desorption Electrospray Ionization Coupled with High-Resolution Mass Spectrometry

    SciTech Connect (OSTI)

    Eckert, Peter A.; Roach, Patrick J.; Laskin, Alexander; Laskin, Julia

    2012-02-07

    Nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was used for the first time for the analysis of liquid petroleum crude oil samples. The analysis was performed in both positive and negative ionization modes using three solvents one of which (acetonitrile/toluene mixture) is commonly used in petroleomics studies while two other polar solvents (acetonitrile/water and methanol/water mixtures) are generally not compatible with petroleum characterization using mass spectrometry. The results demonstrate that nano-DESI analysis efficiently ionizes petroleum constituents soluble in a particular solvent. When acetonitrile/toluene is used as a solvent, nano-DESI generates electrospray-like spectra. In contrast, strikingly different spectra were obtained using acetonitrile/water and methanol/water. Comparison with the literature data indicates that these solvents selectively extract water-soluble constituents of the crude oil. Water-soluble compounds are predominantly observed as sodium adducts in nano-DESI spectra indicating that addition of sodium to the solvent may be a viable approach for efficient ionization of water-soluble crude oil constituents. Nano-DESI enables rapid screening of different classes of compounds in crude oil samples using solvents that are rarely used for petroleum characterization.

  13. Real-time monitoring of volatile organic compounds using chemical ionization mass spectrometry

    DOE Patents [OSTI]

    Mowry, Curtis Dale; Thornberg, Steven Michael

    1999-01-01

    A system for on-line quantitative monitoring of volatile organic compounds (VOCs) includes pressure reduction means for carrying a gaseous sample from a first location to a measuring input location maintained at a low pressure, the system utilizing active feedback to keep both the vapor flow and pressure to a chemical ionization mode mass spectrometer constant. A multiple input manifold for VOC and gas distribution permits a combination of calibration gases or samples to be applied to the spectrometer.

  14. Characterization of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cahill, John F.; Kertesz, Vilmos; Van Berkel, Gary J.

    2015-10-22

    Herein, a commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes weremore » used. The smallest area the system was able to ablate was ~0.544 μm × ~0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (~1.9 μm). With use of a model photoresist surface, known features as small as ~1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. Lastly, with use of a lane scanning mode with ~6 μm × ~6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.« less

  15. Matrix assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) for direct visualization of plant metabolites in situ

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sturtevant, Drew; Lee, Young -Jin; Chapman, Kent D.

    2015-11-22

    Direct visualization of plant tissues by matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has revealed key insights into the localization of metabolites in situ. Recent efforts have determined the spatial distribution of primary and secondary metabolites in plant tissues and cells. Strategies have been applied in many areas of metabolism including isotope flux analyses, plant interactions, and transcriptional regulation of metabolite accumulation. Technological advances have pushed achievable spatial resolution to subcellular levels and increased instrument sensitivity by several orders of magnitude. Furthermore, it is anticipated that MALDI-MSI and other MSI approaches will bring a new level of understanding tomore » metabolomics as scientists will be encouraged to consider spatial heterogeneity of metabolites in descriptions of metabolic pathway regulation.« less

  16. Comprehensive quantification of triacylglycerols in soybean seeds by electrospray ionization mass spectrometry with multiple neutral loss scans

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Maoyin; Butka, Emily; Wang, Xuemin

    2014-10-10

    Soybean seeds are an important source of vegetable oil and biomaterials. The content of individual triacylglycerol species (TAG) in soybean seeds is difficult to quantify in an accurate and rapid way. The present study establishes an approach to quantify TAG species in soybean seeds utilizing an electrospray ionization tandem mass spectrometry with multiple neutral loss scans. Ten neutral loss scans were performed to detect the fatty acyl chains of TAG, including palmitic (P, 1650), linolenic (Ln, 1853), linoleic (L, 1852), oleic (O, 1851), stearic (S, 1850), eicosadienoic (2052), gadoleic (2051), arachidic (2050), erucic (2251), and behenic (2250). The abundance ofmore » ten fatty acyl chains at 46 TAG masses (mass-to-charge ratio, m/z) were determined after isotopic deconvolution and correction by adjustment factors at each TAG mass. The direct sample infusion and multiple internal standards correction allowed a rapid and accurate quantification of TAG species. Ninety-three TAG species were resolved and their levels were determined.The most abundant TAG species were LLL, OLL, LLLn, PLL, OLLn, OOL, POL, and SLL. Many new species were detected and quantified. As a result, this shotgun lipidomics approach should facilitate the study of TAG metabolism and genetic breeding of soybean seeds for desirable TAG content and composition.« less

  17. Comprehensive quantification of triacylglycerols in soybean seeds by electrospray ionization mass spectrometry with multiple neutral loss scans

    SciTech Connect (OSTI)

    Li, Maoyin; Butka, Emily; Wang, Xuemin

    2014-10-10

    Soybean seeds are an important source of vegetable oil and biomaterials. The content of individual triacylglycerol species (TAG) in soybean seeds is difficult to quantify in an accurate and rapid way. The present study establishes an approach to quantify TAG species in soybean seeds utilizing an electrospray ionization tandem mass spectrometry with multiple neutral loss scans. Ten neutral loss scans were performed to detect the fatty acyl chains of TAG, including palmitic (P, 1650), linolenic (Ln, 1853), linoleic (L, 1852), oleic (O, 1851), stearic (S, 1850), eicosadienoic (2052), gadoleic (2051), arachidic (2050), erucic (2251), and behenic (2250). The abundance of ten fatty acyl chains at 46 TAG masses (mass-to-charge ratio, m/z) were determined after isotopic deconvolution and correction by adjustment factors at each TAG mass. The direct sample infusion and multiple internal standards correction allowed a rapid and accurate quantification of TAG species. Ninety-three TAG species were resolved and their levels were determined.The most abundant TAG species were LLL, OLL, LLLn, PLL, OLLn, OOL, POL, and SLL. Many new species were detected and quantified. As a result, this shotgun lipidomics approach should facilitate the study of TAG metabolism and genetic breeding of soybean seeds for desirable TAG content and composition.

  18. MASS SPECTROMETRY

    DOE Patents [OSTI]

    Nier, A.O.C.

    1959-08-25

    A voltage switching apparatus is described for use with a mass spectrometer in the concentratron analysis of several components of a gas mixture. The system automatically varies the voltage on the accelerating electrode of the mass spectrometer through a program of voltages which corresponds to the particular gas components under analysis. Automatic operation may be discontinued at any time to permit the operator to manually select any desired predetermined accelerating voltage. Further, the system may be manually adjusted to vary the accelerating voltage over a wide range.

  19. Molecular Characterization of Organic Aerosol Using Nanospray Desorption/Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    SciTech Connect (OSTI)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Liu, Shang; Weber, Robin; Russell, Lynn; Goldstein, Allen H.

    2013-04-01

    Aerosol samples from the CalNex 2010 field study were analyzed using high resolution mass spectrometry (HR-MS) coupled to a nanospray-desorption/electrospray ionization (nano-DESI) source. The samples were collected in Bakersfield, CA on June 22-23, 2010. The chemical formulas of over 1300 unique molecular species were detected in the mass range of 50-800 m/z. Our analysis focused on identification of two main groups: compounds containing only carbon, hydrogen, and oxygen (CHO only), and nitrogen-containing organic compounds (NOC). The NOC accounted for 35% (by number) of the compounds observed in the afternoon, and for 59% in the early morning samples. By comparing plausible reactant-product pairs, we propose that over 50% of the NOC in each sample could have been formed through reactions transforming carbonyls into imines. The CHO only compounds were dominant in the afternoon suggesting a photochemical source. The average O:C ratios of all observed compounds were fairly consistent throughout the day, ranging from 0.34 in the early morning to 0.37 at night. We conclude that both photooxidation and ammonia chemistry play important roles in forming the compounds observed in this mixed urban-rural environment.

  20. MASS SPECTROMETRY

    DOE Patents [OSTI]

    Friedman, L.

    1962-01-01

    method is described for operating a mass spectrometer to improve its resolution qualities and to extend its period of use substantially between cleanings. In this method, a small amount of a beta emitting gas such as hydrogen titride or carbon-14 methane is added to the sample being supplied to the spectrometer for investigation. The additive establishes leakage paths on the surface of the non-conducting film accumulating within the vacuum chamber of the spectrometer, thereby reducing the effect of an accumulated static charge on the electrostatic and magnetic fields established within the instrument. (AEC)

  1. Three-Dimensional Imaging of Lipids and Metabolites in Tissues by Nanospray Desorption Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Lanekoff, Ingela T.; Burnum-Johnson, Kristin E.; Thomas, Mathew; Cha, Jeeyeon; Dey, Sudhansu K.; yang, Pengxiang; Prieto, Mari; Laskin, Julia

    2015-03-01

    Abstract Three-dimensional (3D) imaging of tissue sections is a new frontier in mass spectrometry imaging (MSI). Here we report on fast 3D imaging of lipids and metabolites associated with mouse uterine decidual cells and embryo at the implantation site on day 6 of pregnancy. 2D imaging of 16-20 serial tissue sections deposited on the same glass slide was performed using nanospray desorption electrospray ionization (nano-DESI) an ambient ionization technique that enables sensitive localized analysis of analytes on surfaces without special sample pre-treatment. In this proof-of-principle study, nano-DESI was coupled to a high-resolution Q-Exactive instrument operated at high repetition rate of >5 Hz with moderate mass resolution of 35,000 (m/?m at m/z 200), which enabled acquisition of the entire 3D image with a spatial resolution of ~150 ?m in less than 4.5 hours. The results demonstrate localization of acetylcholine in the primary decidual zone (PDZ) of the implantation site throughout the depth of the tissue examined, indicating an important role of this signaling molecule in decidualization. Choline and phosphocholine metabolites associated with cell growth are enhanced in the PDZ and abundant in other cellular regions of the implantation site. Very different 3D distributions were obtained for fatty acids (FA), oleic acid and linoleic acid (FA 18:1 and FA 18:2), differing only by one double bond. Localization of FA 18:2 in the PDZ indicates its important role in decidualization while FA 18:1 is distributed more evenly throughout the tissue. In contrast, several lysophosphatidylcholines (LPC) observed in this study show donut-like distributions with localization around the PDZ. Complementary distributions with minimal overlap were observed for LPC 18:0 and FA 18:2 while the 3D image of the potential precursor phosphatidylcholine (PC 36:2) showed a significant overlap with both LPC 18:0 and FA 18:2.

  2. (Applied mass spectrometry in the health sciences)

    SciTech Connect (OSTI)

    Glish, G.L.

    1990-05-03

    The traveler attended the 2nd International Symposium on Applied Mass Spectrometry in the Health Sciences and presented and invited paper. Papers presented that were of interest to ORNL mass spectrometry programs involved ionization of large molecules by electrospray and laser desorption. Other papers of interest included applications of MS/MS for structural elucidation and new instrumentation.

  3. Chemistry of α-pinene and naphthalene oxidation products generated in a Potential Aerosol Mass (PAM) chamber as measured by acetate chemical ionization mass spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chhabra, P. S.; Lambe, A. T.; Canagaratna, M. R.; Stark, H.; Jayne, J. T.; Onasch, T. B.; Davidovits, P.; Kimmel, J. R.; Worsnop, D. R.

    2014-07-01

    Recent developments in high resolution, time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS) have made possible the direct detection of atmospheric organic compounds in real-time with high sensitivity and with little or no fragmentation, including low volatility, highly oxygenated organic vapors that are precursors to secondary organic aerosol formation. Here, for the first time, we examine gas-phase O3 and OH oxidation products of α-pinene and naphthalene formed in the PAM flow reactor with an HR-ToF-CIMS using acetate reagent ion chemistry. Integrated OH exposures ranged from 1.2 × 1011 to 9.7 × 1011 molec cm−3 s, corresponding to approximately 1.0 to 7.5 daysmore » of equivalent atmospheric oxidation. Measured gas-phase organic acids are similar to those previously observed in environmental chamber studies. For both precursors, we find that acetate-CIMS spectra capture both functionalization (oxygen addition) and fragmentation (carbon loss) as a function of OH exposure. The level of fragmentation is observed to increase with increased oxidation. We present a method that estimates vapor pressures of organic molecules using the measured O/C ratio, H/C ratio, and carbon number for each compound detected by the CIMS. The predicted condensed-phase SOA average acid yields and O/C and H/C ratios agree within uncertainties with previous AMS measurements and ambient CIMS results. While acetate reagent ion chemistry is used to selectively measure organic acids, in principle this method can be applied to additional reagent ion chemistries depending on the application.« less

  4. Method for ultra-trace cesium isotope ratio measurements from environmental samples using thermal ionization mass spectrometry

    SciTech Connect (OSTI)

    Snow, Mathew S.; Snyder, Darin C.; Mann, Nick R.; White, Byron M.

    2015-05-01

    135Cs/137Cs isotope ratios can provide the age, origin and history of environmental Cs contamination. Relatively high precision 135Cs/137Cs isotope ratio measurements from samples containing femtogram quantities of 137Cs are needed to accurately track contamination resuspension and redistribution following environmental 137Cs releases; however, mass spectrometric analyses of environmental samples are limited by the large quantities of ionization inhibitors and isobaric interferences which are present at relatively high concentrations in the environment. We report a new approach for Cs purification from environmental samples. An initial ammonium molybdophosphate-polyacrylonitrile (AMP-PAN) column provides a robust method for extracting Cs under a wide variety of sample matrices and mass loads. Cation exchange separations using a second AMP-PAN column result in more than two orders of magnitude greater Cs/Rb separation factors than commercially available strong cation exchangers. Coupling an AMP-PAN cation exchanging step to a microcation column (AG50W resin) enables consistent 2-4% (2?) measurement errors for samples containing 3-6,000 fg 137Cs, representing the highest precision 135Cs/137Cs ratio measurements currently reported for soil samples at the femtogram level.

  5. Molecular Characterization of Organosulfates in Organic Aerosols from Shanghai and Los Angeles Urban Areas by Nanospray-Desorption Electrospray Ionization High-Resolution Mass Spectrometry

    SciTech Connect (OSTI)

    Tao, Shikang; Lu, Xiaohui; Levac, Nicole A.; Bateman, Adam P.; Nguyen, Tran B.; Bones, David L.; Nizkorodov, Sergey; Laskin, Julia; Laskin, Alexander; Yang, Xin

    2014-08-21

    Aerosol samples collected in the urban areas of Shanghai and Los Angeles were analyzed by nanospray-desorption electrospray ionization mass spectrometry (nano-DESI MS) with high mass resolution (m/?m=100,000). Solvent mixtures of acetonitrile/water and acetonitrile/toluene were used to extract and ionize polar and non-polar compounds, respectively. A diverse mixture of oxygenated hydrocarbons, organosulfates, organonitrates, and organics with reduced nitrogen were detected in the Los Angeles sample. Majority of the organics in the Shanghai sample were detected as organosulfates. The dominant organosulfates in the two samples have distinctly different molecular characteristics. Specifically, organosulfates in the Los Angeles sample were dominated by isoprene- or monoterpene-derived products, while organosulfates of yet unknown origin in the Shanghai sample had distinctive characteristics of long aliphatic carbon chains and low degree of oxidation and unsaturation. The use of acetonitrile/toluene solvent facilitated identification of this type of organosulfates, suggesting they could be missed in previous studies relying on sample extraction using common polar solvents. The high molecular weight and low degree of unsaturation and oxidization of the organosulfates detected in the Shanghai sample suggest that they may act as surfactants, and plausibly affect the surface tension and hygroscopicity of the atmospheric particulate matter. We propose that direct esterification of carbonyl or hydroxyl compounds by sulfates or sulfuric acid in liquid phase could be the formation pathway of these special organosulfates. Long-chain alkanes from vehicle emissions might be their precursors.

  6. Matrix assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) for direct visualization of plant metabolites in situ

    SciTech Connect (OSTI)

    Sturtevant, Drew; Lee, Young -Jin; Chapman, Kent D.

    2015-11-22

    Direct visualization of plant tissues by matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has revealed key insights into the localization of metabolites in situ. Recent efforts have determined the spatial distribution of primary and secondary metabolites in plant tissues and cells. Strategies have been applied in many areas of metabolism including isotope flux analyses, plant interactions, and transcriptional regulation of metabolite accumulation. Technological advances have pushed achievable spatial resolution to subcellular levels and increased instrument sensitivity by several orders of magnitude. Furthermore, it is anticipated that MALDI-MSI and other MSI approaches will bring a new level of understanding to metabolomics as scientists will be encouraged to consider spatial heterogeneity of metabolites in descriptions of metabolic pathway regulation.

  7. Application of high-resolution time-of-flight chemical ionization mass spectrometry measurements to estimate volatility distributions of α-pinene and naphthalene oxidation products

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chhabra, P. S.; Lambe, A. T.; Canagaratna, M. R.; Stark, H.; Jayne, J. T.; Onasch, T. B.; Davidovits, P.; Kimmel, J. R.; Worsnop, D. R.

    2015-01-05

    Recent developments in high-resolution time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS) have made it possible to directly detect atmospheric organic compounds in real time with high sensitivity and with little or no fragmentation, including low-volatility, highly oxygenated organic vapors that are precursors to secondary organic aerosol formation. Here, using ions identified by high-resolution spectra from an HR-ToF-CIMS with acetate reagent ion chemistry, we develop an algorithm to estimate the vapor pressures of measured organic acids. The algorithm uses identified ion formulas and calculated double bond equivalencies, information unavailable in quadrupole CIMS technology, as constraints for the number of possible oxygen-containing functionalmore » groups. The algorithm is tested with acetate chemical ionization mass spectrometry (acetate-CIMS) spectra of O3 and OH oxidation products of α-pinene and naphthalene formed in a flow reactor with integrated OH exposures ranged from 1.2 × 1011 to 9.7 × 1011 molec s cm−3, corresponding to approximately 1.0 to 7.5 days of equivalent atmospheric oxidation. Measured gas-phase organic acids are similar to those previously observed in environmental chamber studies. For both precursors, we find that acetate-CIMS spectra capture both functionalization (oxygen addition) and fragmentation (carbon loss) as a function of OH exposure. The level of fragmentation is observed to increase with increased oxidation. The predicted condensed-phase secondary organic aerosol (SOA) average acid yields and O/C and H/C ratios agree within uncertainties with previous chamber and flow reactor measurements and ambient CIMS results. While acetate reagent ion chemistry is used to selectively measure organic acids, in principle this method can be applied to additional reagent ion chemistries depending on the application.« less

  8. Ion Mobility Spectrometry (IMS) and Mass Spectrometry

    SciTech Connect (OSTI)

    Shvartsburg, Alexandre A.

    2010-04-20

    In a media of finite viscosity, the Coulomb force of external electric field moves ions with some terminal speed. This dynamics is controlled by “mobility” - a property of the interaction potential between ions and media molecules. This fact has been used to separate and characterize gas-phase ions in various modes of ion mobility spectrometry (IMS) developed since 1970. Commercial IMS devices were introduced in 1980-s for field detection of volatile traces such as explosives and chemical warfare agents. Coupling to soft-ionization sources, mass spectrometry (MS), and chromatographic methods in 1990-s had allowed IMS to handle complex samples, enabling new applications in biological and environmental analyses, nanoscience, and other areas. Since 2003, the introduction of commercial systems by major instrument vendors started bringing the IMS/MS capability to broad user community. The other major development of last decade has been the differential IMS or “field asymmetric waveform IMS” (FAIMS) that employs asymmetric time-dependent electric field to sort ions not by mobility itself, but by the difference between its values in strong and weak electric fields. Coupling of FAIMS to conventional IMS and stacking of conventional IMS stages have enabled two-dimensional separations that dramatically expand the power of ion mobility methods.

  9. Improvement in Thermal-Ionization Mass Spectrometry (TIMS) using Total Flash Evaporation (TFE) method for lanthanides isotope ratio measurements in transmutation targets

    SciTech Connect (OSTI)

    Mialle, S.; Gourgiotis, A.; Aubert, M.; Stadelmann, G.; Gautier, C.; Isnard, H.

    2011-07-01

    The experiments involved in the PHENIX french nuclear reactor to obtain precise and accurate data on the total capture cross sections of the heavy isotopes and fission products require isotopic ratios measurements with uncertainty of a few per mil. These accurate isotopic ratio measurements are performed with mass spectrometer equipped with multi-collector system. The major difficulty for the analyses of these actinides and fission products is the low quantity of the initial powder enclosed in steel container (3 to 5 mg) and the very low quantities of products formed (several {mu}g) after irradiation. Specific analytical developments are performed by Thermal Ionization Mass Spectrometry (TIMS) to be able to analyse several nanograms of elements with this technique. A specific method of acquisition named Total Flash Evaporation was adapted in this study in the case of lanthanide measurements for quantity deposited on the filament in the order of 2 ng and applied on irradiated fuel. To validate the analytical approach and discuss about the accuracy of the data, the isotopic ratios obtained by TIMS are compared with other mass spectrometric techniques such as Multiple-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS). (authors)

  10. Investigating the Synthesis of Ligated Metal Clusters in Solution Using a Flow Reactor and Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Olivares, Astrid M.; Laskin, Julia; Johnson, Grant E.

    2014-09-18

    The scalable synthesis of subnanometer metal clusters containing an exact number of atoms is of interest due to the highly size-dependent catalytic, electronic and optical properties of these species. While significant research has been conducted on the batch preparation of clusters through reduction synthesis in solution, the processes of metal complex reduction as well as cluster nucleation, growth and post-reduction etching are still not well understood. Herein, we demonstrate a temperature-controlled flow reactor for studying cluster formation in solution at well-defined conditions. Employing this technique methanol solutions of a chloro(triphenylphosphine)gold precursor, 1,4-bis(diphenylphosphino)butane capping ligand and borane-tert-butylamine reducing agent were combined in a mixing tee and introduced into a heated capillary with an adjustable length. In this manner, the temperature dependence of the relative abundance of different ionic reactants, intermediates and products synthesized in real time was characterized using online mass spectrometry. A wide distribution of doubly and triply charged cationic gold clusters was observed as well as smaller singly charged metal-ligand complexes. The results demonstrate that temperature plays a crucial role in determining the relative population of cationic gold clusters and, in general, that higher temperature promotes the formation of doubly charged clusters and singly charged metal-ligand complexes while hindering the growth of triply charged clusters. Moreover, the distribution of clusters observed at elevated temperatures is found to be consistent with that obtained at longer reaction times at room temperature, thereby demonstrating that heating may be used to access cluster distributions characteristic of different stages of reduction synthesis in solution.

  11. Polysialylated N-Glycans Identified in Human Serum Through Combined Developments in Sample Preparation, Separations and Electrospray ionization-mass spectrometry

    SciTech Connect (OSTI)

    Kronewitter, Scott R.; Marginean, Ioan; Cox, Jonathan T.; Zhao, Rui; Hagler, Clay D.; Shukla, Anil K.; Carlson, Timothy S.; Adkins, Joshua N.; Camp, David G.; Moore, Ronald J.; Rodland, Karin D.; Smith, Richard D.

    2014-09-02

    The N-glycan diversity of human serum glycoproteins, i.e. the human blood serum N-glycome, is complex due to the range of glycan structures potentially synthesizable by human glycosylation enzymes. The reported glycome, however, is limited by methods of sample preparation, available analytical platforms, e.g., based upon electrospray ionization-mass spectrometry (ESI-MS), and software tools for data analysis. In this report, several improvements have been implemented in sample preparation and analysis to extend ESI-MS glycan characterization and to provide an improved view of glycan diversity. Sample preparation improvements include acidified, microwave-accelerated, PNGase F N-glycan release, and sodium borohydride reduction were optimized to improve quantitative yields and conserve the number of glycoforms detected. Two-stage desalting (during solid phase extraction and on the analytical column) increased the sensitivity by reducing analyte signal division between multiple reducing-end-forms or cation adducts. On-line separations were improved by using extended length graphitized carbon columns and adding TFA as an acid modifier to a formic acid/reversed phase gradient which provides additional resolving power and significantly improved desorption of both large and heavily sialylated glycans. To improve MS sensitivity and provide gentler ionization conditions at the source-MS interface, subambient pressure ionization with nanoelectrospray (SPIN) has been utilized. When method improvements are combined together with the Glycomics Quintavariate Informed Quantification (GlyQ-IQ) recently described1 these technologies demonstrate the ability to significantly extend glycan detection sensitivity and provide expanded glycan coverage. We demonstrate application of these advances in the context of the human serum glycome, and for which our initial observations include detection of a new class of heavily sialylated N-glycans, including polysialylated N-glycans.

  12. System and method of infrared matrix-assisted laser desorption/ionization mass spectrometry in polyacrylamide gels

    DOE Patents [OSTI]

    Haglund, Jr., Richard F.; Ermer, David R.; Baltz-Knorr, Michelle Lee

    2004-11-30

    A system and method for desorption and ionization of analytes in an ablation medium. In one embodiment, the method includes the steps of preparing a sample having analytes in a medium including at least one component, freezing the sample at a sufficiently low temperature so that at least part of the sample has a phase transition, and irradiating the frozen sample with short-pulse radiation to cause medium ablation and desorption and ionization of the analytes. The method further includes the steps of selecting a resonant vibrational mode of at least one component of the medium and selecting an energy source tuned to emit radiation substantially at the wavelength of the selected resonant vibrational mode. The medium is an electrophoresis medium having polyacrylamide. In one embodiment, the energy source is a laser, where the laser can be a free electron laser tunable to generate short-pulse radiation. Alternatively, the laser can be a solid state laser tunable to generate short-pulse radiation. The laser can emit light at various ranges of wavelength.

  13. Single event mass spectrometry

    DOE Patents [OSTI]

    Conzemius, Robert J.

    1990-01-16

    A means and method for single event time of flight mass spectrometry for analysis of specimen materials. The method of the invention includes pulsing an ion source imposing at least one pulsed ion onto the specimen to produce a corresponding emission of at least one electrically charged particle. The emitted particle is then dissociated into a charged ion component and an uncharged neutral component. The ion and neutral components are then detected. The time of flight of the components are recorded and can be used to analyze the predecessor of the components, and therefore the specimen material. When more than one ion particle is emitted from the specimen per single ion impact, the single event time of flight mass spectrometer described here furnis This invention was made with Government support under Contract No. W-7405-ENG82 awarded by the Department of Energy. The Government has certain rights in the invention.

  14. Effusive molecular beam-sampled Knudsen flow reactor coupled to vacuum ultraviolet single photon ionization mass spectrometry using an external free radical source

    SciTech Connect (OSTI)

    Leplat, N.; Rossi, M. J.

    2013-11-15

    A new apparatus using vacuum ultraviolet single photon ionization mass spectrometry (VUV SPIMS) of an effusive molecular beam emanating from a Knudsen flow reactor is described. It was designed to study free radical-molecule kinetics over a significant temperature range (300630 K). Its salient features are: (1) external free radical source, (2) counterpropagating molecular beam and diffuse VUV photon beam meeting in a crossed-beam ion source of a quadrupole mass spectrometer with perpendicular ion extraction, (3) analog detection of the photocurrent of the free radical molecular cation, and (4) possibility of detecting both free radicals and closed shell species in the same apparatus and under identical reaction conditions owing to the presence of photoelectrons generated by the photoelectric effect of the used VUV-photons. The measured thermal molecular beam-to-background ratio was 6.35 0.39 for Ar and 10.86 1.59 for i-C{sub 4}H{sub 10} at 300 K, a factor of 2.52 and 1.50 smaller, respectively, than predicted from basic gas-dynamic considerations. Operating parameters as well as the performance of key elements of the instrument are presented and discussed. Coupled to an external free radical source a steady-state specific exit flow of 1.6 10{sup 11} and 5.0 10{sup 11} molecule s{sup ?1} cm{sup ?3} of C{sub 2}H{sub 5}{sup } (ethyl) and t-C{sub 4}H{sub 9}{sup } (t-butyl) free radicals have been detected using VUV SPIMS at their molecular ion m/z 29 and 57, respectively, at 300 K.

  15. Linear electric field mass spectrometry

    DOE Patents [OSTI]

    McComas, D.J.; Nordholt, J.E.

    1992-12-01

    A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.

  16. Linear electric field mass spectrometry

    DOE Patents [OSTI]

    McComas, David J.; Nordholt, Jane E.

    1992-01-01

    A mass spectrometer and methods for mass spectrometry. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field.

  17. Constraining the sensitivity of iodide adduct chemical ionization mass spectrometry to multifunctional organic molecules using the collision limit and thermodynamic stability of iodide ion adducts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lopez-Hilfiker, Felipe D.; Iyer, Siddarth; Mohr, Claudia; Lee, Ben H.; D'Ambro, Emma L.; Kurtén, Theo; Thornton, Joel A.

    2016-04-06

    The sensitivity of a chemical ionization mass spectrometer (ions formed per number density of analytes) is fundamentally limited by the collision frequency between reagent ions and analytes, known as the collision limit, the ion–molecule reaction time, and the transmission efficiency of product ions to the detector. We use the response of a time-of-flight chemical ionization mass spectrometer (ToF-CIMS) to N2O5, known to react with iodide at the collision limit, to constrain the combined effects of ion–molecule reaction time, which is strongly influenced by mixing and ion losses in the ion–molecule reaction drift tube. A mass spectrometric voltage scanning procedure elucidatesmore » the relative binding energies of the ion adducts, which influence the transmission efficiency of molecular ions through the electric fields within the vacuum chamber. Together, this information provides a critical constraint on the sensitivity of a ToF-CIMS towards a wide suite of routinely detected multifunctional organic molecules for which no calibration standards exist. We describe the scanning procedure and collision limit determination, and we show results from the application of these constraints to the measurement of organic aerosol composition at two different field locations.« less

  18. Constraining the sensitivity of iodide adduct chemical ionization mass spectrometry to multifunctional organic molecules using the collision limit and thermodynamic stability of iodide ion adducts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lopez-Hilfiker, Felipe D.; Iyer, Siddarth; Mohr, Claudia; Lee, Ben H.; D'Ambro, Emma L.; Kurten, Theo; Thornton, Joel A.

    2016-04-06

    The sensitivity of a chemical ionization mass spectrometer (ions formed per number density of analytes) is fundamentally limited by the collision frequency between reagent ions and analytes, known as the collision limit, the ion–molecule reaction time, and the transmission efficiency of product ions to the detector. We use the response of a time-of-flight chemical ionization mass spectrometer (ToF-CIMS) to N2O5, known to react with iodide at the collision limit, to constrain the combined effects of ion–molecule reaction time, which is strongly influenced by mixing and ion losses in the ion–molecule reaction drift tube. A mass spectrometric voltage scanning procedure elucidatesmore » the relative binding energies of the ion adducts, which influence the transmission efficiency of molecular ions through the electric fields within the vacuum chamber. Together, this information provides a critical constraint on the sensitivity of a ToF-CIMS towards a wide suite of routinely detected multifunctional organic molecules for which no calibration standards exist. Lastly, we describe the scanning procedure and collision limit determination, and we show results from the application of these constraints to the measurement of organic aerosol composition at two different field locations.« less

  19. Symposium on accelerator mass spectrometry

    SciTech Connect (OSTI)

    1981-01-01

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  20. Mass spectrometry for biomarker development

    SciTech Connect (OSTI)

    Wu, Chaochao; Liu, Tao; Baker, Erin Shammel; Rodland, Karin D.; Smith, Richard D.

    2015-06-19

    Biomarkers potentially play a crucial role in early disease diagnosis, prognosis and targeted therapy. In the past decade, mass spectrometry based proteomics has become increasingly important in biomarker development due to large advances in technology and associated methods. This chapter mainly focuses on the application of broad (e.g. shotgun) proteomics in biomarker discovery and the utility of targeted proteomics in biomarker verification and validation. A range of mass spectrometry methodologies are discussed emphasizing their efficacy in the different stages in biomarker development, with a particular emphasis on blood biomarker development.

  1. Novel two-step laser ablation and ionization mass spectrometry (2S-LAIMS) of actor-spectator ice layers: Probing chemical composition of D{sub 2}O ice beneath a H{sub 2}O ice layer

    SciTech Connect (OSTI)

    Yang, Rui Gudipati, Murthy S.

    2014-03-14

    In this work, we report for the first time successful analysis of organic aromatic analytes imbedded in D{sub 2}O ices by novel infrared (IR) laser ablation of a layered non-absorbing D{sub 2}O ice (spectator) containing the analytes and an ablation-active IR-absorbing H{sub 2}O ice layer (actor) without the analyte. With these studies we have opened up a new method for the in situ analysis of solids containing analytes when covered with an IR laser-absorbing layer that can be resonantly ablated. This soft ejection method takes advantage of the tenability of two-step infrared laser ablation and ultraviolet laser ionization mass spectrometry, previously demonstrated in this lab to study chemical reactions of polycyclic aromatic hydrocarbons (PAHs) in cryogenic ices. The IR laser pulse tuned to resonantly excite only the upper H{sub 2}O ice layer (actor) generates a shockwave upon impact. This shockwave penetrates the lower analyte-containing D{sub 2}O ice layer (spectator, a non-absorbing ice that cannot be ablated directly with the wavelength of the IR laser employed) and is reflected back, ejecting the contents of the D{sub 2}O layer into the vacuum where they are intersected by a UV laser for ionization and detection by a time-of-flight mass spectrometer. Thus, energy is transmitted from the laser-absorbing actor layer into the non-absorbing spectator layer resulting its ablation. We found that isotope cross-contamination between layers was negligible. We also did not see any evidence for thermal or collisional chemistry of PAH molecules with H{sub 2}O molecules in the shockwave. We call this shockwave mediated surface resonance enhanced subsurface ablation technique as two-step laser ablation and ionization mass spectrometry of actor-spectator ice layers. This method has its roots in the well-established MALDI (matrix assisted laser desorption and ionization) method. Our method offers more flexibility to optimize both the processesablation and ionization

  2. Microscale mass spectrometry systems, devices and related methods

    DOE Patents [OSTI]

    Ramsey, John Michael

    2016-06-21

    Mass spectrometry systems or assemblies therefore include an ionizer that includes at least one planar conductor, a mass analyzer with a planar electrode assembly, and a detector comprising at least one planar conductor. The ionizer, the mass analyzer and the detector are attached together in a compact stack assembly. The stack assembly has a perimeter that bounds an area that is between about 0.01 mm.sup.2 to about 25 cm.sup.2 and the stack assembly has a thickness that is between about 0.1 mm to about 25 mm.

  3. Electrophoresis-mass spectrometry probe

    DOE Patents [OSTI]

    Andresen, B.D.; Fought, E.R.

    1987-11-10

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface. 8 figs.

  4. Electrophoresis-mass spectrometry probe

    DOE Patents [OSTI]

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  5. Molecular Characterization of S- and N-containing Organic Constituents in Ambient Aerosols by negative ion mode High-Resolution Nanospray Desorption Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    SciTech Connect (OSTI)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Rubitschun, Caitlin L.; Surratt, Jason D.; Goldstein, Allen H.

    2014-11-27

    Samples of ambient aerosols from the 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study were analyzed using Nanospray Desorption Electrospray Ionization High Resolution Mass Spectrometry (nano-DESI/MS). Four samples per day were collected in Bakersfield, CA on June 20-24 with a collection time of 6 hours per sample. Four characteristic groups of organic constituents were identified in the samples: compounds containing carbon, hydrogen, and oxygen only (CHO), sulfur- (CHOS), nitrogen-(CHON), and both nitrogen- and sulfur-containing organics (CHONS). Within the groups, organonitrates, organosulfates, and nitroxy organosulfates were assigned based on accurate mass measurements and elemental ratio comparisons. Changes in the chemical composition of the aerosol samples were observed throughout the day. The number of observed CHO compounds increased in the afternoon samples, suggesting regional photochemical processing as a source. The average number of CHOS compounds had the smallest changes throughout the day, consistent with a more broadly distributed source. Both of the nitrogen-containing groups (CHON and CHONS) had greater numbers of compounds in the night and morning samples, indicating that nitrate radical chemistry was likely a source for those compounds. Most of the compounds were found in submicron particles. The size distribution of CHON compounds was bimodal. We conclude that the majority of the compounds observed were secondary in nature with both biogenic and anthropogenic sources.

  6. Isotope mass spectrometry from 1968 to 1989

    SciTech Connect (OSTI)

    DeBievre, P. )

    1989-11-01

    The principal developments in isotope mass spectrometry are described with respect to instrument construction, detector technology, measurement precision, measurement accuracy, and reference materials. The increase in the application of isotope mass spectrometry is summarized, with special emphasis on its use in safeguards of nuclear materials. The future potential versus the present achievements of the field are discussed.

  7. Fluorohydrogenate Cluster Ions in the Gas Phase: Electrospray Ionization Mass Spectrometry of the [1-Ethyl-3-methylimidazolium+][F(HF)2.3] Ionic Liquid

    SciTech Connect (OSTI)

    Gary S. Groenewold; James E. Delmore; Michael T. Benson; Tetsuya Tsuda; Rika Hagiwara

    2013-12-01

    Electrospray ionization of the fluorohydrogenate ionic liquid [1-ethyl-3-methylimidazolium][F(HF)2.3] ionic liquid was conducted to understand the nature of the anionic species as they exist in the gas phase. Abundant fluorohydrogenate clusters were produced; however, the dominant anion in the clusters was [FHF-], and not the fluoride-bound HF dimers or trimers that are seen in solution. Density functional theory (DFT) calculations suggest that HF molecules are bound to the clusters by about 30 kcal/mol. The DFT-calculated structures of the [FHF-]-bearing clusters show that the favored interactions of the anions are with the methynic and acetylenic hydrogen atoms on the imidazolium cation, forming planar structures similar to those observed in the solid state. A second series of abundant negative ions was also formed that contained [SiF5-] together with the imidazolium cation and the fluorohydrogenate anions that originate from reaction of the spray solution with silicate surfaces.

  8. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    SciTech Connect (OSTI)

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.

    2014-06-17

    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  9. Methods for recalibration of mass spectrometry data

    DOE Patents [OSTI]

    Tolmachev, Aleksey V.; Smith, Richard D.

    2009-03-03

    Disclosed are methods for recalibrating mass spectrometry data that provide improvement in both mass accuracy and precision by adjusting for experimental variance in parameters that have a substantial impact on mass measurement accuracy. Optimal coefficients are determined using correlated pairs of mass values compiled by matching sets of measured and putative mass values that minimize overall effective mass error and mass error spread. Coefficients are subsequently used to correct mass values for peaks detected in the measured dataset, providing recalibration thereof. Sub-ppm mass measurement accuracy has been demonstrated on a complex fungal proteome after recalibration, providing improved confidence for peptide identifications.

  10. Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzi...

    Office of Scientific and Technical Information (OSTI)

    Fourier transform infrared (FTIR) spectroscopy has been used to identify different crystal ... The major adduct ions observed under negative ion conditions were (M+Cl)- at mz 473 and ...

  11. Laser photoionization time-of-flight mass spectrometry of nitrated polycyclic aromatic hydrocarbons and nitrated heterocyclic compounds. Master's thesis

    SciTech Connect (OSTI)

    Noyes, R.A.

    1993-01-01

    Partial Contents: Laser Desorption-Laser Photoionization Time-of-Flight Mass Spectrometry; Basic Principles of TOFMS; Factors Affecting Flight Time; Source of Broadening; Laser Desorption; Theory of Multiphoton Ionization: Application to Mass Spectrometry; Quantum Theory of MPI; Time-Dependent Perturbation Theory; Time-Dependent Coefficients; Probability of a Two-Photon Process; and Attributes of R2PI.

  12. Nanostructure-initiator mass spectrometry biometrics

    DOE Patents [OSTI]

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent

    2015-09-08

    Several embodiments described herein are drawn to methods of identifying an analyte on a subject's skin, methods of generating a fingerprint, methods of determining a physiological change in a subject, methods of diagnosing health status of a subject, and assay systems for detecting an analyte and generating a fingerprint, by nanostructure-initiator mass spectrometry (NIMS).

  13. Optimization Of A Mass Spectrometry Process

    SciTech Connect (OSTI)

    Lopes, Jose; Alegria, F. Correa; Redondo, Luis; Barradas, N. P.; Alves, E.; Rocha, Jorge

    2011-06-01

    In this paper we present and discuss a system developed in order to optimize the mass spectrometry process of an ion implanter. The system uses a PC to control and display the mass spectrum. The operator interacts with the I/O board, that interfaces with the computer and the ion implanter by a LabVIEW code. Experimental results are shown and the capabilities of the system are discussed.

  14. Ambient Mass Spectrometry Imaging Using Direct Liquid Extraction Techniques

    SciTech Connect (OSTI)

    Laskin, Julia; Lanekoff, Ingela

    2015-11-13

    Mass spectrometry imaging (MSI) is a powerful analytical technique that enables label-free spatial localization and identification of molecules in complex samples.1-4 MSI applications range from forensics5 to clinical research6 and from understanding microbial communication7-8 to imaging biomolecules in tissues.1, 9-10 Recently, MSI protocols have been reviewed.11 Ambient ionization techniques enable direct analysis of complex samples under atmospheric pressure without special sample pretreatment.3, 12-16 In fact, in ambient ionization mass spectrometry, sample processing (e.g., extraction, dilution, preconcentration, or desorption) occurs during the analysis.17 This substantially speeds up analysis and eliminates any possible effects of sample preparation on the localization of molecules in the sample.3, 8, 12-14, 18-20 Venter and co-workers have classified ambient ionization techniques into three major categories based on the sample processing steps involved: 1) liquid extraction techniques, in which analyte molecules are removed from the sample and extracted into a solvent prior to ionization; 2) desorption techniques capable of generating free ions directly from substrates; and 3) desorption techniques that produce larger particles subsequently captured by an electrospray plume and ionized.17 This review focuses on localized analysis and ambient imaging of complex samples using a subset of ambient ionization methods broadly defined as “liquid extraction techniques” based on the classification introduced by Venter and co-workers.17 Specifically, we include techniques where analyte molecules are desorbed from solid or liquid samples using charged droplet bombardment, liquid extraction, physisorption, chemisorption, mechanical force, laser ablation, or laser capture microdissection. Analyte extraction is followed by soft ionization that generates ions corresponding to intact species. Some of the key advantages of liquid extraction techniques include the ease

  15. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOE Patents [OSTI]

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  16. Electron Ionization Mass Spectrum of Tellurium Hexafluoride

    SciTech Connect (OSTI)

    Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.

    2015-05-18

    The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.

  17. Automated Surface Sampling Probe for Mass Spectrometry - Energy Innovation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Portal Advanced Materials Advanced Materials Find More Like This Return to Search Automated Surface Sampling Probe for Mass Spectrometry Mass Spectrometry Imaging for Drug Discovery and Pharmaceutical Research Oak Ridge National Laboratory Contact ORNL About This Technology Technology Marketing Summary Dr. Gary Van Berkel and colleagues have developed a liquid microjunction surface sampling probe (LMJ?SSP). The LMJ?SSP provides mass spectrometry with a simple and efficient ambient surface

  18. Mass Spectrometry imaging of plant metabolites | The Ames Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    We are developing and applying mass spectrometry imaging technique to understand plant metabolic biology down to cellular and eventually subcellular level high-spatial...

  19. Method Development and Application of Mass Spectrometry Imaging...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mass spectrometry imaging is making a significant impact in the fields of pathology, medicine and biology. It provides a unique capability to simultaneously measure,...

  20. Giga-Dalton Mass Spectrometry - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Biomass and Biofuels Biomass and Biofuels Advanced Materials Advanced Materials Find More Like This Return to Search Giga-Dalton Mass Spectrometry Major leap forward for Mass Spectrometry Applications to Life Sciences Oak Ridge National Laboratory Contact ORNL About This Technology Technology Marketing SummaryCurrent techniques to study large bio?molecules using mass spectrometer require fragmentation for the mass?to?charge ratios to be within the working range of the mass spectrometer. Analysis

  1. Near edge X-ray absorption mass spectrometry on coronene

    SciTech Connect (OSTI)

    Reitsma, G.; Deuzeman, M. J.; Hoekstra, R.; Schlathölter, T.; Boschman, L.; Hoekstra, S.

    2015-01-14

    We have investigated the photoionization and photodissociation of free coronene cations C{sub 24}H{sub 12}{sup +} upon soft X-ray photoabsorption in the carbon K-edge region by means of a time-of-flight mass spectrometry approach. Core excitation into an unoccupied molecular orbital (below threshold) and core ionization into the continuum both leave a C 1s vacancy, that is subsequently filled in an Auger-type process. The resulting coronene dications and trications are internally excited and cool down predominantly by means of hydrogen emission. Density functional theory was employed to determine the dissociation energies for subsequent neutral hydrogen loss. A statistical cascade model incorporating these dissociation energies agrees well with the experimentally observed dehydrogenation. For double ionization, i.e., formation of intermediate C{sub 24}H{sub 12}{sup 3+⋆}trications, the experimental data hint at loss of H{sup +} ions. This asymmetric fission channel is associated with hot intermediates, whereas colder intermediates predominantly decay via neutral H loss.

  2. Matrix Effects in Biological Mass Spectrometry Imaging: Identification and Compensation

    SciTech Connect (OSTI)

    Lanekoff, Ingela T.; Stevens, Susan; Stenzel-Poore, Mary; Laskin, Julia

    2014-07-21

    Matrix effects in mass spectrometry imaging (MSI) may affect the observed molecular distribution in chemical and biological systems. In this study, we introduce an experimental approach that efficiently compensates for matrix effects in nanospray desorption electrospray ionization (nano-DESI) MSI without introducing any complexity into the experimental protocol. We demonstrate compensation for matrix effects in nano-DESI MSI of phosphatidylcholine (PC) in normal and ischemic mouse brain tissue by doping the nano-DESI solvent with PC standards. Specifically, we use mouse brain tissue of a middle cerebral artery occlusion (MCAO) stroke model with an ischemic region localized to one hemisphere of the brain. Due to similar suppression in ionization of endogenous PC molecules extracted from the tissue and PC standards added to the solvent, matrix effects are eliminated by normalizing the intensity of the sodium and potassium adducts of endogenous PC to the intensity of the corresponding adduct of the PC standard. This approach efficiently compensates for signal variations resulting from differences in the local concentrations of sodium and potassium in tissue sections and from the complexity of the extracted analyte mixture derived from local variations in molecular composition.

  3. Small system for tritium accelerator mass spectrometry

    DOE Patents [OSTI]

    Roberts, Mark L.; Davis, Jay C.

    1993-01-01

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  4. Small system for tritium accelerator mass spectrometry

    DOE Patents [OSTI]

    Roberts, M.L.; Davis, J.C.

    1993-02-23

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and [sup 3]He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  5. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    SciTech Connect (OSTI)

    Watrous, Matthew George; Adamic, Mary Louise; Olson, John Eric; Baeck, D. L.; Fox, R. V.; Hahn, P. A.; Jenson, D. D.; Lister, T. E.

    2015-09-01

    The goal of the project, New Paradigms for Isotope Ratio Mass Spectrometry: Raising the Scientific Profile and Improved Performance for Accelerator Mass Spectrometry (AMS) and Thermal Ionization Mass Spectrometry (TIMS), is to ensure that the ongoing isotope ratio determination capability within the U.S. Department of Energy complex is the world’s best for application to nonproliferation. This report spells out the progress of Task 4, Transition of TIMS to AMS for Iodine Analysis, of the larger project. The subtasks under Task 4 and the accomplishments throughout the three year project life cycle are presented in this report. Progress was made in optimization of chemical extraction, determination of a detection limit for 127Iodine, production of standard materials for AMS analysis quality assurance, facilitation of knowledge exchange with respect to analyzing iodine on an AMS, cross comparison with a world leading AMS laboratory, supercritical fluid extraction of iodine for AMS analysis and electrodeposition of seawater as a direct method of preparation for iodine analysis by AMS. All with the goal of minimizing the time required to stand up an AMS capability for iodine analysis of exposed air filters at INL. An effective extraction method has been developed and demonstrated for iodine analysis of exposed air filters. Innovative techniques to accomplish the cathode preparation for AMS analysis were developed and demonstrated and published. The known gap of a lack of available materials for reference standards in the analysis of iodine by AMS was filled by the preparation of homogenous materials that were calibrated against NIST materials. A minimum limit on the amount of abundant isotope in a sample was determined for AMS analysis. The knowledge exchange occurred with fantastic success. Scientists engaged the international AMS community at conferences, as well as in their laboratories for collaborative work. The supercritical fluid extraction work has positive

  6. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    SciTech Connect (OSTI)

    M. L. Adamic; J. E. Olson; D. D. Jenson; J. G. Eisenmenger; M. G. Watrous

    2012-09-01

    This NA 22 funded research project investigated the transition of iodine isotopic analyses from thermal ionization mass spectrometry (TIMS) to an accelerator mass spectrometry (AMS) system. Previous work (Fiscal Year 2010) had demonstrated comparable data from TIMS and AMS. With AMS providing comparable data with improved background levels and vastly superior sample throughput, improvement in the sample extraction from environmental sample matrices was needed to bring sample preparation throughput closer to the operation level of the instrument. Previous research used an extraction chemistry that was not optimized for yield or refined for reduced labor to prove the principle. This research was done to find an extraction with better yield using less labor per sample to produce a sample ready for the AMS instrument. An extraction method using tetramethyl ammonium hydroxide (TMAH) was developed for removal of iodine species from high volume air filters. The TMAH with gentle heating was superior to the following three extraction methods: ammonium hydroxide aided by sonication, acidic and basic extraction aided by microwave, and ethanol mixed with sodium hydroxide. Taking the iodine from the extraction solvent to being ready for AMS analysis was accomplished by a direct precipitation, as well as, using silver wool to harvest the iodine from the TMAH. Portions of the same filters processed in FY 2010 were processed again with the improved extraction scheme followed by successful analysis by AMS at the Swiss Federal Institute of Technology. The data favorably matched the data obtained in 2010. The time required for analysis has been reduced over the aqueous extraction/AMS approach developed in FY 2010. For a hypothetical batch of 30 samples, the AMS methodology is about 10 times faster than the traditional gas phase chemistry and TIMS analysis. As an additional benefit, background levels for the AMS method are about 1000 times lower than TIMS. This results from the

  7. SAMDI Mass Spectrometry for High Throughput Discovery of Enzyme...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    SAMDI Mass Spectrometry for High Throughput Discovery of Enzyme Function January 15, 2016 11:00AM to 12:00PM Presenter Milan Mrksich, Northwestern University Location Building 446,...

  8. Accelerator mass spectrometry program at the University of Washington

    SciTech Connect (OSTI)

    Farwell, G.W.; Leach, D.D.; Grootes, P.M.; Schmidt, F.H.

    1984-04-10

    The University uses an FN-Tandem for /sup 14/C and /sup 10/Be measurements. Three main problems for accelerator-mass-spectrometry are normalization, stability, and sample preparation. The approach to these problems is discussed. (GHT)

  9. Brominated Tyrosine and Polyelectrolyte Multilayer Analysis by Laser Desorption VUV Postionization and Secondary Ion Mass Spectrometry

    SciTech Connect (OSTI)

    University of Illinois at Chicago; Blaze, Melvin M. T.; Takahashi, Lynelle; Zhou, Jia; Ahmed, Musahid; Gasper, Gerald; Pleticha, F. Douglas; Hanley, Luke

    2011-03-14

    The small molecular analyte 3,5-dibromotyrosine (Br2Y) and chitosan-alginate polyelectrolyte multilayers (PEM) with and without adsorbed Br2Y were analyzed by laser desorption postionization mass spectrometry (LDPI-MS). LDPI-MS using 7.87 eV laser and tunable 8 ? 12.5 eV synchrotron vacuum ultraviolet (VUV) radiation found that desorption of clusters from Br2Y films allowed detection by≤8 eV single photon ionization. Thermal desorption and electronic structure calculations determined the ionization energy of Br2Y to be ~;;8.3?0.1 eV and further indicated that the lower ionization energies of clusters permitted their detection at≤8 eV photon energies. However, single photon ionization could only detect Br2Y adsorbed within PEMs when using either higher photon energies or matrix addition to the sample. All samples were also analyzed by 25 keV Bi3 + secondary ion mass spectrometry (SIMS), with the negative ion spectra showing strong parent ion signal which complemented that observed by LDPI-MS. The negative ion SIMS depended strongly on the high electron affinity of this specific analyte and the analyte?s condensed phase environment.

  10. Apparatus for preparing a sample for mass spectrometry

    DOE Patents [OSTI]

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus for preparing a sample for analysis by a mass spectrometer system. The apparatus has an entry chamber and an ionization chamber separated by a skimmer. A capacitor having two space-apart electrodes followed by one or more ion-imaging lenses is disposed in the ionization chamber. The chamber is evacuated and the capacitor is charged. A valve injects a sample gas in the form of sample pulses into the entry chamber. The pulse is collimated by the skimmer and enters the ionization chamber. When the sample pulse passes through the gap between the electrodes, it discharges the capacitor and is thereby ionized. The ions are focused by the imaging lenses and enter the mass analyzer, where their mass and charge are analyzed.

  11. Apparatus for preparing a sample for mass spectrometry

    DOE Patents [OSTI]

    Villa-Aleman, E.

    1994-05-10

    An apparatus is described for preparing a sample for analysis by a mass spectrometer system. The apparatus has an entry chamber and an ionization chamber separated by a skimmer. A capacitor having two space-apart electrodes followed by one or more ion-imaging lenses is disposed in the ionization chamber. The chamber is evacuated and the capacitor is charged. A valve injects a sample gas in the form of sample pulses into the entry chamber. The pulse is collimated by the skimmer and enters the ionization chamber. When the sample pulse passes through the gap between the electrodes, it discharges the capacitor and is thereby ionized. The ions are focused by the imaging lenses and enter the mass analyzer, where their mass and charge are analyzed. 1 figures.

  12. Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J.; Gan, Jinping; Kertesz, Vilmos

    2015-11-03

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites was studied. Major organs (brain, lung, liver, kidney, muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed themore » same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. Furthermore, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.« less

  13. Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    SciTech Connect (OSTI)

    Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J.; Gan, Jinping; Kertesz, Vilmos

    2015-11-03

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites was studied. Major organs (brain, lung, liver, kidney, muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. Furthermore, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.

  14. Mass Spectrometry Imaging of Biological Tissue: An Approach for Multicenter Studies

    SciTech Connect (OSTI)

    Rompp, Andreas; Both, Jean-Pierre; Brunelle, Alain; Heeren, Ronald M.; Laprevote, Olivier; Prideaux, Brendan; Seyer, Alexandre; Spengler, Bernhard; Stoeckli, Markus; Smith, Donald F.

    2015-03-01

    Mass spectrometry imaging has become a popular tool for probing the chemical complexity of biological surfaces. This led to the development of a wide range of instrumentation and preparation protocols. It is thus desirable to evaluate and compare the data output from different methodologies and mass spectrometers. Here, we present an approach for the comparison of mass spectrometry imaging data from different laboratories (often referred to as multicenter studies). This is exemplified by the analysis of mouse brain sections in five laboratories in Europe and the USA. The instrumentation includes matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF), MALDI-QTOF, MALDIFourier transform ion cyclotron resonance (FTICR), atmospheric-pressure (AP)-MALDI-Orbitrap, and cluster TOF-secondary ion mass spectrometry (SIMS). Experimental parameters such as measurement speed, imaging bin width, and mass spectrometric parameters are discussed. All datasets were converted to the standard data format imzML and displayed in a common open-source software with identical parameters for visualization, which facilitates direct comparison of MS images. The imzML conversion also allowed exchange of fully functional MS imaging datasets between the different laboratories. The experiments ranged from overview measurements of the full mouse brain to detailed analysis of smaller features (depending on spatial resolution settings), but common histological features such as the corpus callosum were visible in all measurements. High spatial resolution measurements of AP-MALDI-Orbitrap and TOF-SIMS showed comparable structures in the low-micrometer range. We discuss general considerations for planning and performing multicenter studies in mass spectrometry imaging. This includes details on the selection, distribution, and preparation of tissue samples as well as on data handling. Such multicenter studies in combination with ongoing activities for reporting guidelines, a common

  15. Miniature quadrupole mass spectrometer having a cold cathode ionization source

    DOE Patents [OSTI]

    Felter, Thomas E.

    2002-01-01

    An improved quadrupole mass spectrometer is described. The improvement lies in the substitution of the conventional hot filament electron source with a cold cathode field emitter array which in turn allows operating a small QMS at much high internal pressures then are currently achievable. By eliminating of the hot filament such problems as thermally "cracking" delicate analyte molecules, outgassing a "hot" filament, high power requirements, filament contamination by outgas species, and spurious em fields are avoid all together. In addition, the ability of produce FEAs using well-known and well developed photolithographic techniques, permits building a QMS having multiple redundancies of the ionization source at very low additional cost.

  16. Coming to a hospital near you: mass spectrometry imaging

    ScienceCinema (OSTI)

    Bowen, Ben

    2014-06-24

    Berkeley Lab's Ben Bowen discusses "Coming to a hospital near you: mass spectrometry imaging" in this Oct. 28, 2013 talk, which is part of a Science at the Theater event entitled Eight Big Ideas. Go here to watch the entire event with all 8 speakers.

  17. Laser Mass Spectrometry in Planetary Science

    SciTech Connect (OSTI)

    Wurz, P.; Whitby, J. A.; Managadze, G. G.

    2009-06-16

    Knowing the chemical, elemental, and isotopic composition of planetary objects allows the study of their origin and evolution within the context of our solar system. Exploration plans in planetary research of several space agencies consider landing spacecraft for future missions. Although there have been successful landers in the past, more landers are foreseen for Mars and its moons, Venus, the jovian moons, and asteroids. Furthermore, a mass spectrometer on a landed spacecraft can assist in the sample selection in a sample-return mission and provide mineralogical context, or identify possible toxic soils on Mars for manned Mars exploration. Given the resources available on landed spacecraft mass spectrometers, as well as any other instrument, have to be highly miniaturised.

  18. Method and apparatus for multispray emitter for mass spectrometry

    DOE Patents [OSTI]

    Smith, Richard D.; Tang, Keqi; Lin, Yuehe

    2004-12-14

    A method and apparatus that utilizes two or more emitters simultaneously to form an electrospray of a sample that is then directed into a mass spectrometer, thereby increasing the total ion current introduced into an electrospray ionization mass spectrometer, given a liquid flow rate of a sample. The method and apparatus are most conveniently constructed as an array of spray emitters fabricated on a single chip, however, the present invention encompasses any apparatus wherein two or more emitters are simultaneously utilized to form an electrospray of a sample that is then directed into a mass spectrometer.

  19. Monitoring Trace Radionuclides by ICP Mass Spectrometry with Femtosecond

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Ablation | The Ames Laboratory Monitoring Trace Radionuclides by ICP Mass Spectrometry with Femtosecond Laser Ablation FWP/Project Description: This project will develop analytical methodology for the use of femtosecond laser ablation sampling and analysis techniques for the rapid screening of samples derived from detection of clandestine nuclear operations, and nuclear non-proliferation and safeguards activities. A state-of-the-art femtosecond laser ablation system in conjunction with

  20. Charge Prediction of Lipid Fragments in Mass Spectrometry

    SciTech Connect (OSTI)

    Schrom, Brian T.; Kangas, Lars J.; Ginovska, Bojana; Metz, Thomas O.; Miller, John H.

    2011-12-18

    An artificial neural network is developed for predicting which fragment is charged and which fragment is neutral for lipid fragment pairs produced from a liquid chromatography tandem mass spectrometry simulation process. This charge predictor is integrated into software developed at PNNL for in silico spectra generation and identification of metabolites known as Met ISIS. To test the effect of including charge prediction in Met ISIS, 46 lipids are used which show a reduction in false positive identifications when the charge predictor is utilized.

  1. Toward a Fieldable Atomic Mass Spectrometer for Safeguards Applications: Sample Preparation and Ionization

    SciTech Connect (OSTI)

    Barinaga, Charles J.; Hager, George J.; Hart, Garret L.; Koppenaal, David W.; Marcus, R. Kenneth; Jones, Sarah MH; Manard, Benjamin T.

    2014-10-31

    The International Atomic Energy Agency’s (IAEA’s) long-term research and development plan calls for the development of new methods to detect misuse at nuclear fuel cycle facilities such as reprocessing and enrichment plants. At enrichment plants, for example, the IAEA’s contemporary safeguards approaches are based on a combination of routine and random inspections that include collection of UF6 samples from in-process material and selected cylinders for subsequent analyses. These analyses include destructive analysis (DA) in a laboratory (typically by mass spectrometry [MS]) for isotopic characterization, and environmental sampling (ES) for subsequent laboratory elemental and isotopic analysis (also both typically by MS). One area of new method development includes moving this kind of isotope ratio analytical capability for DA and ES activities into the field. Some of the reasons for these developments include timeliness of results, avoidance of hazardous material shipments, and guidance for additional sample collecting. However, this capability does not already exist for several reasons, such as that most lab-based chemical and instrumental methods rely on laboratory infrastructure (highly trained staff, power, space, hazardous material handling, etc.) and require significant amounts of consumables (power, compressed gases, etc.). In addition, there are no currently available, fieldable instruments for atomic or isotope ratio analysis. To address these issues, Pacific Northwest National Laboratory (PNNL) and collaborator, Clemson University, are studying key areas that limit the fieldability of isotope ratio mass spectrometry for atomic ions: sample preparation and ionization, and reducing the physical size of a fieldable mass spectrometer. PNNL is seeking simple and robust techniques that could be effectively used by inspectors who may have no expertise in analytical MS. In this report, we present and describe the preliminary findings for three candidate

  2. Structural determination of intact proteins using mass spectrometry

    DOE Patents [OSTI]

    Kruppa, Gary; Schoeniger, Joseph S.; Young, Malin M.

    2008-05-06

    The present invention relates to novel methods of determining the sequence and structure of proteins. Specifically, the present invention allows for the analysis of intact proteins within a mass spectrometer. Therefore, preparatory separations need not be performed prior to introducing a protein sample into the mass spectrometer. Also disclosed herein are new instrumental developments for enhancing the signal from the desired modified proteins, methods for producing controlled protein fragments in the mass spectrometer, eliminating complex microseparations, and protein preparatory chemical steps necessary for cross-linking based protein structure determination.Additionally, the preferred method of the present invention involves the determination of protein structures utilizing a top-down analysis of protein structures to search for covalent modifications. In the preferred method, intact proteins are ionized and fragmented within the mass spectrometer.

  3. Laser Desorption Postionization Mass Spectrometry of Antibiotic-Treated Bacterial Biofilms using Tunable Vacuum Ultraviolet Radiation

    SciTech Connect (OSTI)

    Gasper, Gerald L.; Takahashi, Lynelle K.; Zhou, Jia; Ahmed, Musahid; Moore, Jerry F.; Hanley, Luke

    2010-08-04

    Laser desorption postionization mass spectrometry (LDPI-MS) with 8.0 ? 12.5 eV vacuum ultraviolet synchrotron radiation is used to single photon ionize antibiotics andextracellular neutrals that are laser desorbed both neat and from intact bacterial biofilms. Neat antibiotics are optimally detected using 10.5 eV LDPI-MS, but can be ionized using 8.0 eV radiation, in agreement with prior work using 7.87 eV LDPI-MS. Tunable vacuum ultraviolet radiation also postionizes laser desorbed neutrals of antibiotics and extracellular material from within intact bacterial biofilms. Different extracellular material is observed by LDPI-MS in response to rifampicin or trimethoprim antibiotic treatment. Once again, 10.5 eV LDPI-MS displays the optimum trade-off between improved sensitivity and minimum fragmentation. Higher energy photons at 12.5 eV produce significant parent ion signal, but fragment intensity and other low mass ions are also enhanced. No matrix is added to enhance desorption, which is performed at peak power densities insufficient to directly produce ions, thus allowing observation of true VUV postionization mass spectra of antibiotic treated biofilms.

  4. Atmospheric pressure plasma analysis by modulated molecular beam mass spectrometry

    SciTech Connect (OSTI)

    Aranda Gonzalvo, Y.; Whitmore, T.D.; Rees, J.A.; Seymour, D.L.; Stoffels, E.

    2006-05-15

    Fractional number density measurements for a rf plasma 'needle' operating at atmospheric pressure have been obtained using a molecular beam mass spectrometer (MBMS) system designed for diagnostics of atmospheric plasmas. The MBMS system comprises three differentially pumped stages and a mass/energy analyzer and includes an automated beam-to-background measurement facility in the form of a software-controlled chopper mechanism. The automation of the beam modulation allows the neutral components in the plasma to be rapidly and accurately measured using the mass spectrometer by threshold ionization techniques. Data are reported for plasma generated by a needle plasma source operated using a helium/air mixture. In particular, data for the conversion of atmospheric oxygen and nitrogen into nitric oxide are discussed with reference to its significance for medical applications such as disinfecting wounds and dental cavities and for microsurgery.

  5. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry

    SciTech Connect (OSTI)

    Kyle, Jennifer E.; Zhang, Xing; Weitz, Karl K.; Monroe, Matthew E.; Ibrahim, Yehia M.; Moore, Ronald J.; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S.; Wagoner, Jessica; Polyak, Stephen J.; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin S.

    2016-01-01

    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Liquid chromatography and mass spectrometry (LC-MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids’ biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are unresolvable using present LC-MS approaches. Here we show that combining structurally-based ion mobility spectrometry (IMS) with LC-MS measurements distinguishes lipid isomers and allows insight into biological and disease processes.

  6. Future Directions of Structural Mass Spectrometry using Hydroxyl Radical Footprinting

    SciTech Connect (OSTI)

    J Kiselar; M Chance

    2011-12-31

    Hydroxyl radical protein footprinting coupled to mass spectrometry has been developed over the last decade and has matured to a powerful method for analyzing protein structure and dynamics. It has been successfully applied in the analysis of protein structure, protein folding, protein dynamics, and protein-protein and protein-DNA interactions. Using synchrotron radiolysis, exposure of proteins to a 'white' X-ray beam for milliseconds provides sufficient oxidative modification to surface amino acid side chains, which can be easily detected and quantified by mass spectrometry. Thus, conformational changes in proteins or protein complexes can be examined using a time-resolved approach, which would be a valuable method for the study of macromolecular dynamics. In this review, we describe a new application of hydroxyl radical protein footprinting to probe the time evolution of the calcium-dependent conformational changes of gelsolin on the millisecond timescale. The data suggest a cooperative transition as multiple sites in different molecular subdomains have similar rates of conformational change. These findings demonstrate that time-resolved protein footprinting is suitable for studies of protein dynamics that occur over periods ranging from milliseconds to seconds. In this review, we also show how the structural resolution and sensitivity of the technology can be improved as well. The hydroxyl radical varies in its reactivity to different side chains by over two orders of magnitude, thus oxidation of amino acid side chains of lower reactivity are more rarely observed in such experiments. Here we demonstrate that the selected reaction monitoring (SRM)-based method can be utilized for quantification of oxidized species, improving the signal-to-noise ratio. This expansion of the set of oxidized residues of lower reactivity will improve the overall structural resolution of the technique. This approach is also suggested as a basis for developing hypothesis

  7. Co-registered Topographical, Band Excitation Nanomechanical, and Mass Spectral Imaging Using a Combined Atomic Force Microscopy/Mass Spectrometry Platform

    SciTech Connect (OSTI)

    Ovchinnikova, Olga S.; Tai, Tamin; Bocharova, Vera; Okatan, Mahmut Baris; Belianinov, Alex; Kertesz, Vilmos; Jesse, Stephen; Van Berkel, Gary J.

    2015-03-18

    The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrating for the first time co-registered topographical, band excitation nanomechanical, and mass spectral imaging of a surface using a single instrument is reported. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for pyrolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. We discuss the basic instrumental setup and operation and the multimodal imaging capability and utility are demonstrated using a phase separated polystyrene/poly(2-vinylpyridine) polymer blend thin film. The topography and band excitation images showed that the valley and plateau regions of the thin film surface were comprised primarily of one of the two polymers in the blend with the mass spectral chemical image used to definitively identify the polymers at the different locations. Data point pixel size for the topography (390 nm x 390 nm), band excitation (781 nm x 781 nm), mass spectrometry (690 nm x 500 nm) images was comparable and submicrometer in all three cases, but the data voxel size for each of the three images was dramatically different. The topography image was uniquely a surface measurement, whereas the band excitation image included information from an estimated 10 nm deep into the sample and the mass spectral image from 110-140 nm in depth. Moreover, because of this dramatic sampling depth variance, some differences in the band excitation and mass spectrometry chemical images were observed and were interpreted to indicate the presence of a buried interface in the sample. The spatial resolution of the mass spectral image was estimated to be between 1.5 m 2.6 m, based on the ability to distinguish surface features in that image that were also observed in the other images.

  8. Co-registered Topographical, Band Excitation Nanomechanical, and Mass Spectral Imaging Using a Combined Atomic Force Microscopy/Mass Spectrometry Platform

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ovchinnikova, Olga S.; Tai, Tamin; Bocharova, Vera; Okatan, Mahmut Baris; Belianinov, Alex; Kertesz, Vilmos; Jesse, Stephen; Van Berkel, Gary J.

    2015-03-18

    The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrating for the first time co-registered topographical, band excitation nanomechanical, and mass spectral imaging of a surface using a single instrument is reported. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for pyrolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. We discuss the basic instrumental setup and operation and the multimodal imaging capability and utility are demonstrated using a phase separated polystyrene/poly(2-vinylpyridine) polymer blend thin film. The topography and band excitation images showedmore » that the valley and plateau regions of the thin film surface were comprised primarily of one of the two polymers in the blend with the mass spectral chemical image used to definitively identify the polymers at the different locations. Data point pixel size for the topography (390 nm x 390 nm), band excitation (781 nm x 781 nm), mass spectrometry (690 nm x 500 nm) images was comparable and submicrometer in all three cases, but the data voxel size for each of the three images was dramatically different. The topography image was uniquely a surface measurement, whereas the band excitation image included information from an estimated 10 nm deep into the sample and the mass spectral image from 110-140 nm in depth. Moreover, because of this dramatic sampling depth variance, some differences in the band excitation and mass spectrometry chemical images were observed and were interpreted to indicate the presence of a buried interface in the sample. The spatial resolution of the mass spectral image was estimated to be between 1.5 m 2.6 m, based on the ability to distinguish surface features in that image that were also observed in the other images.« less

  9. Heavy resid asphaltene characterization using high resolution and laser desorption mass spectrometry

    SciTech Connect (OSTI)

    Hunt, J.E.; Kim, Y.; Winans, R.E.

    1995-12-31

    Resid is the nondistillable portion of crude oil, generally thought to consist largely of unsaturated molecules of considerable size and ring number. Such molecules must be upgraded to more saturated compounds if they are to be used as fuel sources. Current processing of resid is performed though coking, thermal and catalytic cracking, deasphalting and hydroprocessing. Thermal treatments, however, produce large quantities of low-value coke and hydroprocessing is expensive. Asphaltenes comprise the most process resistant portion of the resid. They contain high concentrations of heteroatoms and a high degree of unsaturation. Because these undesirable characteristics are concentrated in asphaltenes, finding an improved method of upgrading asphaltenes is a prerequisite to improving the upgrading of whole resid to viable fuel. Asphaltenes have, at present, only an operational definition. They are insoluble in straight chain saturated hydrocarbons. Very little is known about the structure of compounds in asphaltenes. They are a highly diverse group of compounds that are resistant to analysis by conventional methods. Conclusions about the structures of asphaltenes tends to be speculative. In this study desorption electron impact (HREIMS), chemical ionization high resolution mass spectrometry (HRCIMS), and laser desorption mass spectrometry (LD) have been applied to deasphalted oils (DAO) and asphaltenes derived from heavy Maya resid. LD data should yield information on the high molecular weight aromatic compounds, while HRMS can provide molecular characterization.

  10. Method for analyzing the mass of a sample using a cold cathode ionization source mass filter

    DOE Patents [OSTI]

    Felter, Thomas E.

    2003-10-14

    An improved quadrupole mass spectrometer is described. The improvement lies in the substitution of the conventional hot filament electron source with a cold cathode field emitter array which in turn allows operating a small QMS at much high internal pressures then are currently achievable. By eliminating of the hot filament such problems as thermally "cracking" delicate analyte molecules, outgassing a "hot" filament, high power requirements, filament contamination by outgas species, and spurious em fields are avoid all together. In addition, the ability of produce FEAs using well-known and well developed photolithographic techniques, permits building a QMS having multiple redundancies of the ionization source at very low additional cost.

  11. Method for predicting peptide detection in mass spectrometry

    DOE Patents [OSTI]

    Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA

    2010-07-13

    A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.

  12. A nanostructure-initiator mass spectrometry-based enzyme activity assay

    SciTech Connect (OSTI)

    Siuzdak, Gary; Northen, Trent R.; Lee, Jinq-Chyi; Hoang, Linh; Raymond, Jason; Hwang, Der-Ren; Yannone, Steven M.; Wong, Chi-Huey; Siuzdak, Gary

    2008-03-10

    We describe a Nanostructure-Initiator Mass Spectrometry (NIMS) enzymatic (Nimzyme) assay in which enzyme substrates are immobilized on the mass spectrometry surface by using fluorous-phase interactions. This 'soft' immobilization allows efficient desorption/ionization while also enabling the use of surface-washing steps to reduce signal suppression from complex biological samples, which results from the preferential retention of the tagged products and reactants. The Nimzyme assay is sensitive to subpicogram levels of enzyme, detects both addition and cleavage reactions (sialyltransferase and galactosidase), is applicable over a wide range of pHs and temperatures, and can measure activity directly from crude cell lysates. The ability of the Nimzyme assay to analyze complex mixtures is illustrated by identifying and directly characterizing {beta}-1,4-galactosidase activity from a thermophilic microbial community lysate. The optimal enzyme temperature and pH were found to be 65 C and 5.5, respectively, and the activity was inhibited by both phenylethyl-{beta}-d-thiogalactopyranoside and deoxygalactonojirimycin. Metagenomic analysis of the community suggests that the activity is from an uncultured, unsequenced {gamma}-proteobacterium. In general, this assay provides an efficient method for detection and characterization of enzymatic activities in complex biological mixtures prior to sequencing or cloning efforts. More generally, this approach may have important applications for screening both enzymatic and inhibitor libraries, constructing and screening glycan microarrays, and complementing fluorous-phase organic synthesis. The interest in leveraging mass spectrometry for studying enzyme activities in complex biological samples derives from its high sensitivity and specificity; however, signal suppression and significant sample preparation requirements limit its overall utility (1). Here we describe a Nanostructure-Initiator Mass Spectrometry (NIMS) enzymatic (Nimzyme

  13. Multi-matrix, dual polarity, tandem mass spectrometry imaging strategy applied to a germinated maize seed: toward mass spectrometry imaging of an untargeted metabolome

    SciTech Connect (OSTI)

    Feenstra, Adam D.; Hansen, Rebecca L.; Lee, Young Jin

    2015-08-27

    Mass spectrometry imaging (MSI) provides high spatial resolution information that is unprecedented in traditional metabolomics analyses; however, the molecular coverage is often limited to a handful of compounds and is insufficient to understand overall metabolomic changes of a biological system. Here, we propose an MSI methodology to increase the diversity of chemical compounds that can be imaged and identified, in order to eventually perform untargeted metabolomic analysis using MSI. We use the desorption/ionization bias of various matrixes for different metabolite classes along with dual polarities and a tandem MSI strategy. The use of multiple matrixes and dual polarities allows us to visualize various classes of compounds, while data-dependent MS/MS spectra acquired in the same MSI scans allow us to identify the compounds directly on the tissue. In a proof of concept application to a germinated corn seed, a total of 166 unique ions were determined to have high-quality MS/MS spectra, without counting structural isomers, of which 52 were identified as unique compounds. According to an estimation based on precursor MSI datasets, we expect over five hundred metabolites could be potentially identified and visualized once all experimental conditions are optimized and an MS/MS library is available. Finally, metabolites involved in the glycolysis pathway and tricarboxylic acid cycle were imaged to demonstrate the potential of this technology to better understand metabolic biology.

  14. Multi-matrix, dual polarity, tandem mass spectrometry imaging strategy applied to a germinated maize seed: toward mass spectrometry imaging of an untargeted metabolome

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Feenstra, Adam D.; Hansen, Rebecca L.; Lee, Young Jin

    2015-08-27

    Mass spectrometry imaging (MSI) provides high spatial resolution information that is unprecedented in traditional metabolomics analyses; however, the molecular coverage is often limited to a handful of compounds and is insufficient to understand overall metabolomic changes of a biological system. Here, we propose an MSI methodology to increase the diversity of chemical compounds that can be imaged and identified, in order to eventually perform untargeted metabolomic analysis using MSI. We use the desorption/ionization bias of various matrixes for different metabolite classes along with dual polarities and a tandem MSI strategy. The use of multiple matrixes and dual polarities allows usmore » to visualize various classes of compounds, while data-dependent MS/MS spectra acquired in the same MSI scans allow us to identify the compounds directly on the tissue. In a proof of concept application to a germinated corn seed, a total of 166 unique ions were determined to have high-quality MS/MS spectra, without counting structural isomers, of which 52 were identified as unique compounds. According to an estimation based on precursor MSI datasets, we expect over five hundred metabolites could be potentially identified and visualized once all experimental conditions are optimized and an MS/MS library is available. Finally, metabolites involved in the glycolysis pathway and tricarboxylic acid cycle were imaged to demonstrate the potential of this technology to better understand metabolic biology.« less

  15. Focus on Advancing High Performance Mass Spectrometry, Honoring Dr. Richard D. Smith, Recipient of the 2013 Award for a Distinguished Contribution in Mass Spectrometry

    SciTech Connect (OSTI)

    Baker, Erin Shammel; Muddiman, David C.; Loo, Joseph

    2014-12-01

    This special focus issue of the Journal of the American Society for Mass Spectrometry celebrates the accomplishments of Dr. Richard D. Smith, the recipient of the 2013ASMS Award for a Distinguished Contribution in Mass Spectrometry, and who serves as a Battelle Fellow, Chief Scientist in the Biological Sciences Division, and Director of Proteomics Research at Pacific Northwest National Laboratory (PNNL) in Richland, WA. The award is for his development of the electrodynamic ion funnel.

  16. Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

    SciTech Connect (OSTI)

    Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.; Smith, Richard D.; Tang, Keqi

    2014-12-01

    Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utility of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.

  17. Trace elements in coal by glow discharge mass spectrometry

    SciTech Connect (OSTI)

    Jacobs, M.L.; Wilson, C.R.; Pestovich, J. Jr.

    1995-08-01

    A need and a demand exist for determining trace elements in coal and coal related by-products, especially those elements which may potentially be a health hazard. The provisions of the 1990 clean air act require that the EPA evaluate the emissions of electric utilities for trace elements and other potentially hazardous organic compounds. The coal fired electric utility industry supplies roughly 60% of the total generating capacity of 2,882,525 million kilowatt hours (nearly 3 trillion kilowatt hours) generated in the U.S. This is accomplished by 414 power plants scattered across the country that burned 813,508,000 short tons of coal in 1993. The relative volatility of some inorganic constituents in coal makes them more prone to be emitted to the atmosphere following combustion. The production of analytical data for trace elements is known to be a difficult task in coal and by-products of coal combustion (fly ash, bottom ash, gas streams, etc.), in terms of both sample collection and analytical determinations. There are several common analytical methods available to the analyst to determine trace elements in coal and coal by-products. In general analytical germs, the material to be analyzed can be totally solubilized (or extracted), or the elements analytes can be determined in the material as a solid. A relatively new elemental technique, Glow Discharge Mass Spectrometry (GDMS) can be used with solids as well. This new analytical technique had never before been applied directly to coal. The radio frequency-glow discharge quadropole mass spectrometer was used to analyze coal directly for the first time ever by rf-GDMS. The rf-GDMS technique is described.

  18. Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline analysis of atmospheric gas and aerosol species

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Krechmer, Jordan E.; Groessl, Michael; Zhang, Xuan; Junninen, Heikki; Massoli, Paola; Lambe, Andrew T.; Kimmel, Joel R.; Cubison, Michael J.; Graf, Stephan; Lin, Ying-Hsuan; et al

    2016-07-25

    Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS–MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS–MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI–IMS–MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambientmore » field campaign in the forested SE US. The ambient IMS–MS signals are consistent with laboratory IMS–MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS–MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS–MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of

  19. One-photon mass-analyzed threshold ionization (MATI) spectroscopy of pyridine: Determination of accurate ionization energy and cationic structure

    SciTech Connect (OSTI)

    Lee, Yu Ran; Kang, Do Won; Kim, Hong Lae E-mail: hlkim@kangwon.ac.kr; Kwon, Chan Ho E-mail: hlkim@kangwon.ac.kr

    2014-11-07

    Ionization energies and cationic structures of pyridine were intensively investigated utilizing one-photon mass-analyzed threshold ionization (MATI) spectroscopy with vacuum ultraviolet radiation generated by four-wave difference frequency mixing in Kr. The present one-photon high-resolution MATI spectrum of pyridine demonstrated a much finer and richer vibrational structure than that of the previously reported two-photon MATI spectrum. From the MATI spectrum and photoionization efficiency curve, the accurate ionization energy of the ionic ground state of pyridine was confidently determined to be 73 570 ± 6 cm{sup −1} (9.1215 ± 0.0007 eV). The observed spectrum was almost completely assigned by utilizing Franck-Condon factors and vibrational frequencies calculated through adjustments of the geometrical parameters of cationic pyridine at the B3LYP/cc-pVTZ level. A unique feature unveiled through rigorous analysis was the prominent progression of the 10 vibrational mode, which corresponds to in-plane ring bending, and the combination of other totally symmetric fundamentals with the ring bending overtones, which contribute to the geometrical change upon ionization. Notably, the remaining peaks originate from the upper electronic state ({sup 2}A{sub 2}), as predicted by high-resolution photoelectron spectroscopy studies and symmetry-adapted cluster configuration interaction calculations. Based on the quantitatively good agreement between the experimental and calculated results, it was concluded that upon ionization the pyridine cation in the ground electronic state should have a planar structure of C{sub 2v} symmetry through the C-N axis.

  20. IDENTIFICATION OF STAPHYLOCOCCAL SPECIES BASED ON VARIATIONS IN PROTEIN SEQUENCES (MASS SPECTROMETRY) AND DNA SEQUENCE (sodA MICROARRAY)

    SciTech Connect (OSTI)

    Kooken, Jennifer M.; Fox, Karen F.; Fox, Alvin; Altomare, Diego; Creek, Kim E.; Wunschel, David S.; Pajares-Merino, Sara; Martinez-Ballesteros, Ilargi; Garaizar, Javier; Oyarzabal, Omar A.; Samadpour, Mansour

    2014-02-03

    IDENTIFICATION OF STAPHYLOCOCCAL SPECIES BASED ON VARIATIONS IN PROTEIN SEQUENCES (MASS SPECTROMETRY) AND DNA SEQUENCE (sodA MICROARRAY)

  1. MAINTAINING HIGH RESOLUTION MASS SPECTROMETRY CAPABILITIES FOR NATIONAL NUCLEAR SECURITY ADMINISTRATION APPLICATIONS

    SciTech Connect (OSTI)

    Wyrick, S.; Cordaro, J.; Reeves, G.; Mcintosh, J.; Mauldin, C.; Tietze, K.; Varble, D.

    2011-06-06

    The Department of Energy (DOE) National Nuclear Security Administration (NNSA) has a specialized need for analyzing low mass gas species at very high resolutions. The currently preferred analytical method is electromagnetic sector mass spectrometry. This method allows the NNSA Nuclear Security Enterprise (NSE) to resolve species of similar masses down to acceptable minimum detection limits (MDLs). Some examples of these similar masses are helium-4/deuterium and carbon monoxide/nitrogen. Through the 1980s and 1990s, there were two vendors who supplied and supported these instruments. However, with declining procurements and down turns in the economy, the supply of instruments, service and spare parts from these vendors has become less available, and in some cases, nonexistent. The largest NSE user of this capability is the Savannah River Site (SRS), located near Aiken, South Carolina. The Research and Development Engineering (R&DE) Group in the Savannah River National Laboratory (SRNL) investigated the areas of instrument support that were needed to extend the life cycle of these aging instruments. Their conclusions, as to the focus areas of electromagnetic sector mass spectrometers to address, in order of priority, were electronics, software and hardware. Over the past 3-5 years, the R&DE Group has designed state of the art electronics and software that will allow high resolution legacy mass spectrometers, critical to the NNSA mission, to be operated for the foreseeable future. The funding support for this effort has been from several sources, including the SRS Defense Programs, NNSA Readiness Campaign, Pantex Plant and Sandia National Laboratory. To date, electronics systems have been upgraded on one development system at SRNL, two production systems at Pantex and one production system at Sandia National Laboratory. An NSE working group meets periodically to review strategies going forward. The R&DE Group has also applied their work to the electronics for a

  2. Electron Flood Charge Compensation Device for Ion Trap Secondary Ion Mass Spectrometry

    SciTech Connect (OSTI)

    Appelhans, Anthony David; Ward, Michael Blair; Olson, John Eric

    2002-11-01

    During secondary ion mass spectrometry (SIMS) analyses of organophosphorous compounds adsorbed onto soils, the measured anion signals were lower than expected and it was hypothesized that the low signals could be due to sample charging. An electron flood gun was designed, constructed and used to investigate sample charging of these and other sample types. The flood gun was integrated into one end cap of an ion trap secondary ion mass spectrometer and the design maintained the geometry of the self-stabilizing extraction optics used in this instrument. The SIMION ion optics program was used to design the flood gun, and experimental results agreed with the predicted performance. Results showed the low anion signals from the soils were not due to sample charging. Other insulating and conducting samples were tested using both a ReO4- and a Cs+ primary ion beam. The proximity of the sample and electron source to the ion trap aperture resulted in generation of background ions in the ion trap via electron impact (EI) ionization during the period the electron gun was flooding the sample region. When using the electron gun with the ReO4- primary beam, the required electron current was low enough that the EI background was negligible; however, the high electron flood current required with the Cs+ beam produced background EI ions that degraded the quality of the mass spectra. The consequences of the EI produced cations will have to be evaluated on a sample-by-sample basis when using electron flood. It was shown that the electron flood gun could be intentionally operated to produce EI spectra in this instrument. This offers the opportunity to measure, nearly simultaneously, species evaporating from a sample, via EI, and species bound to the surface, via SIMS.

  3. Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight (CXIDB ID 16)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Loh, N. Duane

    2012-06-20

    This deposition includes the aerosol diffraction images used for phasing, fractal morphology, and time-of-flight mass spectrometry. Files in this deposition are ordered in subdirectories that reflect the specifics.

  4. Improvements to Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for Quantitative Analysis using Short Pulse UV Laser | The Ames Laboratory Improvements to Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry for Quantitative Analysis using Short Pulse UV Laser FWP/Project Description: Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a non-destructive method for trace elemental analysis of solids. Trace element composition can be useful in forensic applications for matching or attribution studies, in which a material

  5. Effect of neutrino rest mass on ionization equilibrium freeze-out

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Grohs, Evan Bradley; Fuller, George M.; Kishimoto, Chad T.; Paris, Mark W.

    2015-12-23

    We show how small neutrino rest masses can increase the expansion rate near the photon decoupling epoch in the early Universe, causing an earlier, higher temperature freeze-out for ionization equilibrium compared to the massless neutrino case. This yields a larger free-electron fraction, thereby affecting the photon diffusion length differently than the sound horizon at photon decoupling. This neutrino-mass and recombination effect depends strongly on the neutrino rest masses. Ultimately, though below current sensitivity, this effect could be probed by next-generation cosmic microwave background experiments, giving another observational handle on neutrino rest mass.

  6. RAPID DETERMINATION OF 237 NP AND PU ISOTOPES IN WATER BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY

    SciTech Connect (OSTI)

    Maxwell, S.; Jones, V.; Culligan, B.; Nichols, S.; Noyes, G.

    2010-06-23

    A new method that allows rapid preconcentration and separation of plutonium and neptunium in water samples was developed for the measurement of {sup 237}Np and Pu isotopes by inductively-coupled plasma mass spectrometry (ICP-MS) and alpha spectrometry; a hybrid approach. {sup 238}U can interfere with {sup 239}Pu measurement by ICP-MS as {sup 238}UH{sup +} mass overlap and {sup 237}Np via peak tailing. The method provide enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then moving Pu to DGA resin for additional removal of uranium. The decontamination factor for uranium from Pu is almost 100,000 and the decontamination factor for U from Np is greater than 10,000. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration is performed using a streamlined calcium phosphate precipitation method. Purified solutions are split between ICP-MS and alpha spectrometry so that long and short-lived Pu isotopes can be measured successfully. The method allows for simultaneous extraction of 20 samples (including QC samples) in 4 to 6 hours, and can also be used for emergency response. {sup 239}Pu, {sup 242}Pu and {sup 237}Np were measured by ICP-MS, while {sup 236}Pu, {sup 238}Pu, and {sup 239}Pu were measured by alpha spectrometry.

  7. Development of Soft Ionization for Particulate Organic Detection with the Aerodyne Aerosol Mass Spectrometer

    SciTech Connect (OSTI)

    Trimborn, A; Williams, L R; Jayne, J T; Worsnop, D R

    2008-06-19

    During this DOE SBIR Phase II project, we have successfully developed several soft ionization techniques, i.e., ionization schemes which involve less fragmentation of the ions, for use with the Aerodyne time-of-flight aerosol mass spectrometer (ToF-AMS). Vacuum ultraviolet single photon ionization was demonstrated in the laboratory and deployed in field campaigns. Vacuum ultraviolet single photon ionization allows better identification of organic species in aerosol particles as shown in laboratory experiments on single component particles, and in field measurements on complex multi-component particles. Dissociative electron attachment with lower energy electrons (less than 30 eV) was demonstrated in the measurement of particulate organics in chamber experiments in Switzerland, and is now a routine approach with AMS systems configured for bipolar, negative ion detection. This technique is particularly powerful for detection of acidic and other highly oxygenated secondary organic aerosol (SOA) chemical functionality. Low energy electron ionization (10 to 12 eV) is also a softer ionization approach routinely available to AMS users. Finally, Lithium ion attachment has been shown to be sensitive to more alkyl-like chemical functionality in SOA. Results from Mexico City are particularly exciting in observing changes in SOA molecular composition under different photochemical/meteorological conditions. More recent results detecting biomass burns at the Montana fire lab have demonstrated quantitative and selective detection of levoglucosan. These soft ionization techniques provide the ToF-AMS with better capability for identifying organic species in ambient atmospheric aerosol particles. This, in turn, will allow more detailed study of the sources, transformations and fate of organic-containing aerosol.

  8. Mass spectrometry in identification of ecotoxicants including chemical and biological warfare agents

    SciTech Connect (OSTI)

    Lebedev, Albert T. . E-mail: lebedev@org.chem.msu.ru

    2005-09-01

    Mass spectrometry is a unique tool to detect and identify trace levels of organic and bioorganic compounds as well as microorganisms in the environment. The range of potential chemical warfare (CW) and biological warfare (BW) agents is very broad. An important advantage of mass spectrometry over other techniques involves potential for full spectrum detection of chemical and biological agents including mid-spectrum materials (i.e. bioactive peptides, toxins, etc.) for which biological approaches are inadequate. Being very fast (seconds and minutes), extremely sensitive (zeptomoles 10{sup -21}), and informative (detailed qualitative and quantitative composition of mixtures containing hundreds of chemicals), mass spectrometry is a principal analytical tool at the sites of destruction of CW. Due to its unique features, mass spectrometry is applied not only for the detection of CW agents, but for the analysis of products of metabolism and degradation of these agents in organisms or environment as well. The present paper deals with some examples of successful application of mass spectrometry for the analyses of ecotoxicants, chemical warfare agents, explosives, and microorganisms including biology warfare agents.

  9. Apparatus and methods for continuous beam fourier transform mass spectrometry

    DOE Patents [OSTI]

    McLuckey, Scott A.; Goeringer, Douglas E.

    2002-01-01

    A continuous beam Fourier transform mass spectrometer in which a sample of ions to be analyzed is trapped in a trapping field, and the ions in the range of the mass-to-charge ratios to be analyzed are excited at their characteristic frequencies of motion by a continuous excitation signal. The excited ions in resonant motions generate real or image currents continuously which can be detected and processed to provide a mass spectrum.

  10. SEARCH FOR IONIZED JETS TOWARD HIGH-MASS YOUNG STELLAR OBJECTS

    SciTech Connect (OSTI)

    Guzman, Andres E.; Garay, Guido; Brooks, Kate J.; Voronkov, Maxim A.

    2012-07-01

    We are carrying out multi-frequency radio continuum observations, using the Australia Telescope Compact Array, to systematically search for collimated ionized jets toward high-mass young stellar objects (HMYSOs). Here we report observations at 1.4, 2.4, 4.8, and 8.6 GHz, made with angular resolutions of about 7'', 4'', 2'', and 1'', respectively, toward six objects of a sample of 33 southern HMYSOs thought to be in very early stages of evolution. The objects in the sample were selected from radio and infrared catalogs by having positive radio spectral indices and being luminous (L{sub bol} > 2 Multiplication-Sign 10{sup 4} L{sub Sun }), but underluminous in radio emission compared with that expected from its bolometric luminosity. This criterion makes the radio sources good candidates for being ionized jets. As part of this systematic search, two ionized jets have been discovered: one previously published and the other reported here. The rest of the observed candidates correspond to three hypercompact H II regions and two ultracompact H II regions. The two jets discovered are associated with two of the most luminous (7 Multiplication-Sign 10{sup 4} and 1.0 Multiplication-Sign 10{sup 5} L{sub Sun }) HMYSOs known to harbor this type of object, showing that the phenomena of collimated ionized winds appear in the formation process of stars at least up to masses of {approx}20 M{sub Sun} and provide strong evidence for a disk-mediated accretion scenario for the formation of high-mass stars. From the incidence of jets in our sample, we estimate that the jet phase in high-mass protostars lasts for {approx}4 Multiplication-Sign 10{sup 4} yr.

  11. Electron impact and chemical ionization mass spectral analysis of a volatile uranyl derivative

    SciTech Connect (OSTI)

    Reutter, D.J.; Hardy, D.R.

    1981-01-01

    Quadrupole mass spectral analysis of the volatile uranium ligand complex bis (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium-di-n-butyl sulfoxide is described utilizing electron impact (EI) and methane chemical ionization (CI) ion sources. All major ions are tentatively identified and the potential usefulness of this complex for determining uranium isotope /sup 235/U//sup 238/U abundance is demonstrated.

  12. Time-of-flight secondary ion mass spectrometry of deuterated linear poly(dimethylsiloxane)

    SciTech Connect (OSTI)

    Zhang, X.K.; Stuart, J.O.; Clarson, S.J. ); Sabata, A. ); Beaucage, G. )

    1994-08-29

    Mass spectrometry (MS) has previously proved to be very valuable for characterizing the thermal decomposition of poly-(dimethylsiloxane) (PDMS) via pyrolysis-MS. Secondary ion mass spectrometry (SIMS) has also been applied to identify the various fragments characteristic of PDMS and thus give fingerprint'' spectra for identification purposes. This paper describes the characterization of deuterated linear PDMS -[(CD[sub 3])[sub 2]SiO][sub n]- using time-of-flight secondary ion mass spectrometry. The work is part of a program investigating the conformations and interactions of deuterated siloxanes in isotopic blends -[(CD[sub 3])[sub 2]SiO][sub n]-/-[CH[sub 3][sub 2]SiO][sub n]- using small-angle neutron scattering. It is therefore clearly important to demonstrate that no deuterium/hydrogen exchanges occurred during the synthetic methodology used.

  13. Noise reduction in negative-ion quadrupole mass spectrometry

    DOE Patents [OSTI]

    Chastagner, Philippe

    1993-01-01

    A quadrupole mass spectrometer (QMS) system having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

  14. Noise reduction in negative-ion quadrupole mass spectrometry

    DOE Patents [OSTI]

    Chastagner, P.

    1993-04-20

    A quadrupole mass spectrometer (QMS) system is described having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

  15. Utilizing the Inherent Electrolysis in a Chip-Based Nanoelectrospray Emitter System to Facilitate Selective Ionization and Mass Spectrometric Analysis of Metallo Alkylporphyrins

    SciTech Connect (OSTI)

    Van Berkel, Gary J; Kertesz, Vilmos

    2012-01-01

    A commercially available chip-based infusion nanoelectrospray ionization system was used to ionize metallo alkylporphyrins for mass spectrometric detection and structure elucidation by mass spectrometry. Different ionic forms of model compounds (nickel (II), vanadyl (II), copper (II) and cobalt (II) octaethylporphyrin) were created by using two different types of conductive pipette tips supplied with the device. These pipette tips provide the conductive contact to solution at which the electrolysis process inherent to electrospray takes places in the device. The original unmodified, bare carbon-impregnated plastic pipette tips, were exploited to intentionally electrochemically oxidize (ionize) the porphyrins to form molecular radical cations for detection. Use of modified pipette tips, with a surface coating devised to inhibit analyte mass transport to the surface, was shown to limit the ionic species observed in the mass spectra of these porphyrins largely, but not exclusively, to the protonated molecule. Under the conditions of these experiments, the effective upper potential limit for oxidation with the uncoated pipette tip was 1.1 V or less and the coated pipette tips effectively prevented the oxidation of analytes with redox potentials greater than about 0.25 V. Product ion spectra of either molecular ionic species could be used to determine the alkyl chain length on the porphyrin macrocycle. The utility of this electrochemical ionization approach for the analysis of naturally occurring samples was demonstrated using nickel geoporphyrin fractions isolated from Gilsonite bitumen. Acquiring neutral loss spectra as a means to improve the specificity of detection in these complex natural samples was also illustrated.

  16. Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

    DOE Patents [OSTI]

    Brennan, T.M.; Hammons, B.E.; Tsao, J.Y.

    1992-12-15

    A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth. 3 figs.

  17. Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

    DOE Patents [OSTI]

    Brennan, Thomas M.; Hammons, B. Eugene; Tsao, Jeffrey Y.

    1992-01-01

    A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth.

  18. RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH

    SciTech Connect (OSTI)

    Maxwell, S.; Jones, V.

    2009-05-27

    A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. 239Pu, 242Pu, 237Np, 243Am, 234U, 235U and 238U were measured by ICP-MS, while 236Pu, 238Pu, 239Pu, 241Am, 243Am and 244Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead

  19. Apparatus and method for hydrogen and oxygen mass spectrometry of the terrestrial magnetosphere

    DOE Patents [OSTI]

    Funsten, Herbert O.; Dors, Eric E.; Harper, Ronnie W.; Reisenfeld, Daniel B.

    2007-05-15

    A detector element for mass spectrometry of a flux of heavy and light ions, that includes: a first detector to detect light ions that transit through a foil operatively placed in front of the first detector, and a second detector that detects the flux of heavy and light ions.

  20. A compact permanent magnet cyclotrino for accelerator mass spectrometry

    SciTech Connect (OSTI)

    Young, A.T.; Clark, D.J.; Kunkel, W.B.; Leung, K.N.; Li, C.Y.

    1995-02-01

    The authors describe the development of a new instrument for the detection of trace amounts of rare isotopes, a Cyclotron Mass Spectrometer (CMS). A compact low energy cyclotron optimized for high mass resolution has been designed and has been fabricated. The instrument has high sensitivity and is designed to measure carbon-14 at abundances of < 10{sup {minus}12}. A novel feature of the instrument is the use of permanent magnets to energize the iron poles of the cyclotron. The instrument uses axial injection, employing a spiral inflector. The instrument has been assembled and preliminary measurements of the magnetic field show that it has a uniformity on the order of 2 parts in 10{sup 4}.

  1. Ion source for high-precision mass spectrometry

    DOE Patents [OSTI]

    Todd, Peter J.; McKown, Henry S.; Smith, David H.

    1984-01-01

    The invention is directed to a method for increasing the precision of positive-ion relative abundance measurements conducted in a sector mass spectrometer having an ion source for directing a beam of positive ions onto a collimating slit. The method comprises incorporating in the source an electrostatic lens assembly for providing a positive-ion beam of circular cross section for collimation by the slit.

  2. Ion source for high-precision mass spectrometry

    DOE Patents [OSTI]

    Todd, P.J.; McKown, H.S.; Smith, D.H.

    1982-04-26

    The invention is directed to a method for increasing the precision of positive-ion relative abundance measurements conducted in a sector mass spectrometer having an ion source for directing a beam of positive ions onto a collimating slit. The method comprises incorporating in the source an electrostatic lens assembly for providing a positive-ion beam of circular cross section for collimation by the slit. 2 figures, 3 tables.

  3. (Resonance ionization spectroscopy)

    SciTech Connect (OSTI)

    Young, J.P.

    1990-10-11

    J. P. Young attended the Fifth International Symposium on Resonance Ionization Spectroscopy and presented an invited oral presentation on research he and coworkers had carried out in applying diode lasers to resonance ionization mass spectrometry. A summary of the conference is given along with an assessment of some of the presentations that the author found of interest. Young also visited Professor Marassi at the University of Camerino to present a seminar and discuss mutual interests in a new molten salt research project of the author. Some of the studies at Camerino are described. Ideas concerning the author's research that came from private discussions are also presented here.

  4. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-03-02

    We used an electrostatic size classification technique to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Moreover, we counted size-segregated particles with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized bymore » the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10-5 to 10-11. Free molecular heat and mass transfer theory was

  5. Isolation and Puification of Uranium Isotopes for Measurement by Mass-Spectrometry (233, 234, 235, 236, 238U) and Alpha Spectrometry (232U)

    SciTech Connect (OSTI)

    Marinelli, R; Hamilton, T; Brown, T; Marchetti, A; Williams, R; Tumey, S

    2006-05-30

    This report describes a standardized methodology used by researchers from the Center for Accelerator Mass Spectrometry (CAMS) (Energy and Environment Directorate) and the Environmental Radiochemistry Group (Chemistry and Materials Science Directorate) at the Lawrence Livermore National Laboratory (LLNL) for the full isotopic analysis of uranium from solution. The methodology has largely been developed for use in characterizing the uranium composition of selected nuclear materials but may also be applicable to environmental studies and assessments of public, military or occupational exposures to uranium using in-vitro bioassay monitoring techniques. Uranium isotope concentrations and isotopic ratios are measured using a combination of Multi Collector Inductively Coupled Plasma Mass Spectrometry (MC ICP-MS), Accelerator Mass Spectrometry (AMS) and Alpha Spectrometry.

  6. Sampling probe for microarray read out using electrospray mass spectrometry

    DOE Patents [OSTI]

    Van Berkel, Gary J.

    2004-10-12

    An automated electrospray based sampling system and method for analysis obtains samples from surface array spots having analytes. The system includes at least one probe, the probe including an inlet for flowing at least one eluting solvent to respective ones of a plurality of spots and an outlet for directing the analyte away from the spots. An automatic positioning system is provided for translating the probe relative to the spots to permit sampling of any spot. An electrospray ion source having an input fluidicly connected to the probe receives the analyte and generates ions from the analyte. The ion source provides the generated ions to a structure for analysis to identify the analyte, preferably being a mass spectrometer. The probe can be a surface contact probe, where the probe forms an enclosing seal along the periphery of the array spot surface.

  7. An Optimized Informatics Pipeline for Mass Spectrometry-Based Peptidomics

    SciTech Connect (OSTI)

    Wu, Chaochao; Monroe, Matthew E.; Xu, Zhe; Slysz, Gordon W.; Payne, Samuel H.; Rodland, Karin D.; Liu, Tao; Smith, Richard D.

    2015-12-26

    Comprehensive MS analysis of peptidome, the intracellular and intercellular products of protein degradation, has the potential to provide novel insights on endogenous proteolytic processing and their utility in disease diagnosis and prognosis. Along with the advances in MS instrumentation, a plethora of proteomics data analysis tools have been applied for direct use in peptidomics; however an evaluation of the currently available informatics pipelines for peptidomics data analysis has yet to be reported. In this study, we set off by evaluating the results of several popular MS/MS database search engines including MS-GF+, SEQUEST and MS-Align+ for peptidomics data analysis, followed by identification and label-free quantification using the well-established accurate mass and time (AMT) tag and newly developed informed quantification (IQ) approaches, both based on direct LC-MS analysis. Our result demonstrated that MS-GF+ outperformed both SEQUEST and MS-Align+ in identifying peptidome peptides. Using a database established from the MS-GF+ peptide identifications, both the AMT tag and IQ approaches provided significantly deeper peptidome coverage and less missing value for each individual data set than the MS/MS methods, while achieving robust label-free quantification. Besides having an excellent correlation with the AMT tag quantification results, IQ also provided slightly higher peptidome coverage than AMT. Taken together, we propose an optimal informatics pipeline combining MS-GF+ for initial database searching with IQ (or AMT) for identification and label-free quantification for high-throughput, comprehensive and quantitative peptidomics analysis.

  8. An Adaptable Multiple Power Source for Mass Spectrometry and other Scientific Instruments

    SciTech Connect (OSTI)

    Lin, Tzu-Yung; Anderson, Gordon A.; Norheim, Randolph V.; Prost, Spencer A.; Lamarche, Brian L.; Leach, Franklin E.; Auberry, Kenneth J.; Smith, Richard D.; Koppenaal, David W.; Robinson, Errol W.; Pasa-Tolic, Ljiljana

    2015-09-18

    Power supplies are commonly used in the operation of many types of scientific equipment, including mass spectrometers and ancillary instrumentation. A generic modern mass spectrometer comprises an ionization source, such as electrospray ionization (ESI), ion transfer devices such as ion funnels and multipole ion guides, and ion signal detection apparatus. Very often such platforms include, or are interfaced with ancillary elements in order to manipulate samples before or after ionization. In order to operate such scientific instruments, numerous direct current (DC) channels and radio frequency (RF) signals are required, along with other controls such as temperature regulation. In particular, DC voltages in the range of ±400 V, along with MHz range RF signals with peak-to-peak amplitudes in the hundreds of volts range are commonly used to transfer ionized samples under vacuum. Additionally, an ESI source requires a high voltage (HV) DC source capable of producing several thousand volts and heaters capable of generating temperatures up to 300°C. All of these signals must be properly synchronized and managed in order to carry out ion trapping, accumulation and detection.

  9. Mass Spectrometry Data from the Biological MS Data and Software Distribution Center

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Anderson, Gordon

    The mass spectrometry capabilities at Pacific Northwest National Laboratory (PNNL) are primarily applied to biological research, with an emphasis on proteomics and metabolomics. Many of these cutting-edge mass spectrometry capabilities and bioinformatics methods are housed in the Department of Energy's Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility operated by PNNL. These capabilities have been developed and acquired through cooperation between the EMSL national scientific user program and PNNL programmatic research. At the website of the Biological MS Data and Software Distribution Center, the following resources are made available: PNNL-developed software tools and source code, PNNL-generated raw data and processed results, links to publications that used the data and results available on this site, and tutorials and user manuals. [taken from http://omics.pnl.gov/

  10. Accelerator Mass Spectrometry | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Accelerator Mass Spectrometry at ANL and ORNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science Applications of Nuclear Science Archives Small Business Innovation Research / Small Business Technology Transfer Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585

  11. Identification of Methanococcus Jannaschii Proteins in 2-D Gel Electrophoresis Patterns by Mass Spectrometry

    DOE R&D Accomplishments [OSTI]

    Liang, X.

    1998-06-10

    The genome of Methanococcus jannaschii has been sequenced completely and has been found to contain approximately 1,770 predicted protein-coding regions. When these coding regions are expressed and how their expression is regulated, however, remain open questions. In this work, mass spectrometry was combined with two-dimensional gel electrophoresis to identify which proteins the genes produce under different growth conditions, and thus investigate the regulation of genes responsible for functions characteristic of this thermophilic representative of the methanogenic Archaea.

  12. Determination of atmospheric carbonyl sulfide by isotope dilution gas chromatography/mass spectrometry

    SciTech Connect (OSTI)

    Lewin, E.E.; Taggart, R.L.; Lalevic, M.; Bandy, A.R.

    1987-05-01

    A gas chromatography/mass spectrometry (GB/MS) method for determining atmospheric carbonyl sulfide (OCS) with a precision better than 2% is reported. High precision and insensitivity to sample loss and changes in detector response were achieved by using isotopically labeled OCS as an internal standard. Tenax, Molecular Sieve 5A, Carbosieve B, and Carbosieve S were evaluated for collecting atmospheric OCS. Molecular Sieve 5A provided the best trapping and recovery efficiencies.

  13. Mass spectrometry

    SciTech Connect (OSTI)

    Gramlich, J.W. )

    1989-11-01

    The limiting factor to the absolute accuracy of isotopic measurements is no longer instrumentation hardware. This article discusses how greater understanding and control of the chemistry of sample purification, gravimetric blending of separated isotopes, filament loading, and the physico-chemical processes occurring at the high-temperature filament will be necessary before the advantages of robotic sample preparation and filament loading and automated analysis can be attained. Such improved understanding is seen to be an essential procursor to controlling and reducing the uncertainty in isotopic ratio measurements to one part in 10{sup 5}.

  14. Final LDRD report : development of sample preparation methods for ChIPMA-based imaging mass spectrometry of tissue samples.

    SciTech Connect (OSTI)

    Maharrey, Sean P.; Highley, Aaron M.; Behrens, Richard, Jr.; Wiese-Smith, Deneille

    2007-12-01

    The objective of this short-term LDRD project was to acquire the tools needed to use our chemical imaging precision mass analyzer (ChIPMA) instrument to analyze tissue samples. This effort was an outgrowth of discussions with oncologists on the need to find the cellular origin of signals in mass spectra of serum samples, which provide biomarkers for ovarian cancer. The ultimate goal would be to collect chemical images of biopsy samples allowing the chemical images of diseased and nondiseased sections of a sample to be compared. The equipment needed to prepare tissue samples have been acquired and built. This equipment includes an cyro-ultramicrotome for preparing thin sections of samples and a coating unit. The coating unit uses an electrospray system to deposit small droplets of a UV-photo absorbing compound on the surface of the tissue samples. Both units are operational. The tissue sample must be coated with the organic compound to enable matrix assisted laser desorption/ionization (MALDI) and matrix enhanced secondary ion mass spectrometry (ME-SIMS) measurements with the ChIPMA instrument Initial plans to test the sample preparation using human tissue samples required development of administrative procedures beyond the scope of this LDRD. Hence, it was decided to make two types of measurements: (1) Testing the spatial resolution of ME-SIMS by preparing a substrate coated with a mixture of an organic matrix and a bio standard and etching a defined pattern in the coating using a liquid metal ion beam, and (2) preparing and imaging C. elegans worms. Difficulties arose in sectioning the C. elegans for analysis and funds and time to overcome these difficulties were not available in this project. The facilities are now available for preparing biological samples for analysis with the ChIPMA instrument. Some further investment of time and resources in sample preparation should make this a useful tool for chemical imaging applications.

  15. Molecular Beam Mass Spectrometry (MBMS) (Revised) (Fact Sheet), National Bioenergy Center Laboratory Capabilities (NBCLC), NREL (National Renewable Energy Laboratory)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Beam Mass Spectrometry Enabling fundamental understanding of thermochemical biomass conversion and biomass composition recalcitrance NREL has six molecular beam mass spectrometers (MBMS): two stationary systems; two field-deployable systems, customized for use in industrial environments; and two additional high-throughput stationary systems with autosamplers. NREL's custom-built molecular beam mass spectrometers provide: * Rapid quantitation of reactive species in high temperature environments *

  16. Ultra-high-mass mass spectrometry with charge discrimination using cryogenic detectors

    DOE Patents [OSTI]

    Frank, Matthias; Mears, Carl A.; Labov, Simon E.; Benner, W. Henry

    1999-01-01

    An ultra-high-mass time-of-flight mass spectrometer using a cryogenic particle detector as an ion detector with charge discriminating capabilities. Cryogenic detectors have the potential for significantly improving the performance and sensitivity of time-of-flight mass spectrometers, and compared to ion multipliers they exhibit superior sensitivity for high-mass, slow-moving macromolecular ions and can be used as "stop" detectors in time-of-flight applications. In addition, their energy resolving capability can be used to measure the charge state of the ions. Charge discrimination is very valuable in all time-of-flight mass spectrometers. Using a cryogenically-cooled Nb-Al.sub.2 O.sub.3 -Nb superconductor-insulator-superconductor (SIS) tunnel junction (STJ) detector operating at 1.3 K as an ion detector in a time-of-flight mass spectrometer for large biomolecules it was found that the STJ detector has charge discrimination capabilities. Since the cryogenic STJ detector responds to ion energy and does not rely on secondary electron production, as in the conventionally used microchannel plate (MCP) detectors, the cryogenic detector therefore detects large molecular ions with a velocity-independent efficiency approaching 100%.

  17. Investigation of the chemical interface in the soybean–aphid and rice–bacteria interactions using MALDI-mass spectrometry imaging

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Klein, Adam T.; Yagnik, Gargey B.; Hohenstein, Jessica D.; Ji, Zhiyuan; Zi, Jiachen; Reichert, Malinda D.; MacIntosh, Gustavo C.; Yang, Bing; Peters, Reuben J.; Vela, Javier; et al

    2015-04-27

    Mass spectrometry imaging (MSI) is an emerging technology for high-resolution plant biology. It has been utilized to study plant–pest interactions, but limited to the surface interfaces. Here we expand the technology to explore the chemical interactions occurring inside the plant tissues. Two sample preparation methods, imprinting and fracturing, were developed and applied, for the first time, to visualize internal metabolites of leaves in matrix-assisted laser desorption ionization (MALDI)-MSI. This is also the first time nanoparticle-based ionization was implemented to ionize diterpenoid phytochemicals that were difficult to analyze with traditional organic matrices. The interactions between rice–bacterium and soybean–aphid were investigated asmore » two model systems to demonstrate the capability of high-resolution MSI based on MALDI. Localized molecular information on various plant- or pest-derived chemicals provided valuable insight for the molecular processes occurring during the plant–pest interactions. Basically, salicylic acid and isoflavone based resistance was visualized in the soybean–aphid system and antibiotic diterpenoids in rice–bacterium interactions.« less

  18. Investigation of the chemical interface in the soybeanaphid and ricebacteria interactions using MALDI-mass spectrometry imaging

    SciTech Connect (OSTI)

    Klein, Adam T.; Yagnik, Gargey B.; Hohenstein, Jessica D.; Ji, Zhiyuan; Zi, Jiachen; Reichert, Malinda D.; MacIntosh, Gustavo C.; Yang, Bing; Peters, Reuben J.; Vela, Javier; Lee, Young Jin

    2015-04-27

    Mass spectrometry imaging (MSI) is an emerging technology for high-resolution plant biology. It has been utilized to study plantpest interactions, but limited to the surface interfaces. Here we expand the technology to explore the chemical interactions occurring inside the plant tissues. Two sample preparation methods, imprinting and fracturing, were developed and applied, for the first time, to visualize internal metabolites of leaves in matrix-assisted laser desorption ionization (MALDI)-MSI. This is also the first time nanoparticle-based ionization was implemented to ionize diterpenoid phytochemicals that were difficult to analyze with traditional organic matrices. The interactions between ricebacterium and soybeanaphid were investigated as two model systems to demonstrate the capability of high-resolution MSI based on MALDI. Localized molecular information on various plant- or pest-derived chemicals provided valuable insight for the molecular processes occurring during the plantpest interactions. Basically, salicylic acid and isoflavone based resistance was visualized in the soybeanaphid system and antibiotic diterpenoids in ricebacterium interactions.

  19. Dilution-Free Analysis from Picoliter Droplets by Nano-Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Kelly, Ryan T.; Page, Jason S.; Marginean, Ioan; Tang, Keqi; Smith, Richard D.

    2009-09-01

    The expanding role of microfluidics for chemical and biochemical analysis is due to factors including the favorable scaling of separation performance with reduced channel dimensions,[1] flexibility afforded by computer-aided device design, and the ability to integrate multiple sample handling and analysis steps into a single platform.[2] Such devices enable smaller liquid volumes and sample sizes to be handled than can be achieved on the benchtop, where sub-microliter volumes are difficult to work with and where sample losses to the surfaces of multiple reaction vessels become prohibitive. A particularly attractive microfluidic platform for sample-limited analyses employs aqueous droplets or plugs encapsulated by an immiscible oil.[3,4] Each droplet serves as a discrete compartment or reaction chamber enabling, e.g., high throughput screening[5,6] and kinetic studies[7-9] of femto- to nanoliter samples, as well as the encapsulation[10-12] and lysis[10] of individual cells with limited dilution of the cellular contents

  20. An Analysis of Nuclear Fuel Burnup in the AGR 1 TRISO Fuel Experiment Using Gamma Spectrometry, Mass Spectrometry, and Computational Simulation Techniques

    SciTech Connect (OSTI)

    Jason M. Harp; Paul A. Demkowicz; Phillip L. Winston; James W. Sterbentz

    2014-10-01

    AGR 1 was the first in a series of experiments designed to test US TRISO fuel under high temperature gas-cooled reactor irradiation conditions. This experiment was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) and is currently undergoing post irradiation examination (PIE) at INL and Oak Ridge National Laboratory. One component of the AGR 1 PIE is the experimental evaluation of the burnup of the fuel by two separate techniques. Gamma spectrometry was used to non destructively evaluate the burnup of all 72 of the TRISO fuel compacts that comprised the AGR 1 experiment. Two methods for evaluating burnup by gamma spectrometry were developed, one based on the Cs 137 activity and the other based on the ratio of Cs 134 and Cs 137 activities. Burnup values determined from both methods compared well with the values predicted from simulations. The highest measured burnup was 20.1 %FIMA for the direct method and 20.0 %FIMA for the ratio method (compared to 19.56% FIMA from simulations). An advantage of the ratio method is that the burnup of the cylindrical fuel compacts can determined in small (2.5 mm) axial increments and an axial burnup profile can be produced. Destructive chemical analysis by inductively coupled mass spectrometry (ICP MS) was then performed on selected compacts that were representative of the expected range of fuel burnups in the experiment to compare with the burnup values determined by gamma spectrometry. The compacts analyzed by mass spectrometry had a burnup range of 19.3 % FIMA to 10.7 % FIMA. The mass spectrometry evaluation of burnup for the four compacts agreed well with the gamma spectrometry burnup evaluations and the expected burnup from simulation. For all four compacts analyzed by mass spectrometry, the maximum range in the three experimentally determined values and the predicted value was 6% or less. The results confirm the accuracy of the nondestructive burnup evaluation from gamma spectrometry for TRISO

  1. An analysis of nuclear fuel burnup in the AGR-1 TRISO fuel experiment using gamma spectrometry, mass spectrometry, and computational simulation techniques

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Harp, Jason M.; Demkowicz, Paul A.; Winston, Philip L.; Sterbentz, James W.

    2014-09-03

    AGR 1 was the first in a series of experiments designed to test US TRISO fuel under high temperature gas-cooled reactor irradiation conditions. This experiment was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) and is currently undergoing post irradiation examination (PIE) at INL and Oak Ridge National Laboratory. One component of the AGR 1 PIE is the experimental evaluation of the burnup of the fuel by two separate techniques. Gamma spectrometry was used to non destructively evaluate the burnup of all 72 of the TRISO fuel compacts that comprised the AGR 1 experiment. Two methodsmore » for evaluating burnup by gamma spectrometry were developed, one based on the Cs 137 activity and the other based on the ratio of Cs 134 and Cs 137 activities. Burnup values determined from both methods compared well with the values predicted from simulations. The highest measured burnup was 20.1% FIMA for the direct method and 20.0% FIMA for the ratio method (compared to 19.56% FIMA from simulations). An advantage of the ratio method is that the burnup of the cylindrical fuel compacts can determined in small (2.5 mm) axial increments and an axial burnup profile can be produced. Destructive chemical analysis by inductively coupled mass spectrometry (ICP MS) was then performed on selected compacts that were representative of the expected range of fuel burnups in the experiment to compare with the burnup values determined by gamma spectrometry. The compacts analyzed by mass spectrometry had a burnup range of 19.3% FIMA to 10.7% FIMA. The mass spectrometry evaluation of burnup for the four compacts agreed well with the gamma spectrometry burnup evaluations and the expected burnup from simulation. For all four compacts analyzed by mass spectrometry, the maximum range in the three experimentally determined values and the predicted value was 6% or less. Furthermore, the results confirm the accuracy of the nondestructive burnup evaluation from gamma

  2. Analytical Validation of Accelerator Mass Spectrometry for Pharmaceutical Development: the Measurement of Carbon-14 Isotope Ratio.

    SciTech Connect (OSTI)

    Keck, B D; Ognibene, T; Vogel, J S

    2010-02-05

    Accelerator mass spectrometry (AMS) is an isotope based measurement technology that utilizes carbon-14 labeled compounds in the pharmaceutical development process to measure compounds at very low concentrations, empowers microdosing as an investigational tool, and extends the utility of {sup 14}C labeled compounds to dramatically lower levels. It is a form of isotope ratio mass spectrometry that can provide either measurements of total compound equivalents or, when coupled to separation technology such as chromatography, quantitation of specific compounds. The properties of AMS as a measurement technique are investigated here, and the parameters of method validation are shown. AMS, independent of any separation technique to which it may be coupled, is shown to be accurate, linear, precise, and robust. As the sensitivity and universality of AMS is constantly being explored and expanded, this work underpins many areas of pharmaceutical development including drug metabolism as well as absorption, distribution and excretion of pharmaceutical compounds as a fundamental step in drug development. The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of {sup 14}C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the {sup 14}C label), stable across samples storage conditions for at least one year, linear over 4 orders of magnitude with an analytical range from one tenth Modern to at least 2000 Modern (instrument specific). Further, accuracy was excellent between 1 and 3 percent while precision expressed as coefficient of variation is between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of carbon-14 (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with {sup 14}C corresponds to 30 fg

  3. 230Th-234U Age-Dating Uranium by Mass Spectrometry

    SciTech Connect (OSTI)

    Williams, R W; Gaffney, A M

    2012-04-18

    This is the standard operating procedure used by the Isotope Ratio Mass Spectrometry Group of the Chemical Sciences Division at LLNL for the preparation of a sample of uranium oxide or uranium metal for {sup 230}Th-{sup 234}U age-dating. The method described here includes the dissolution of a sample of uranium oxide or uranium metal, preparation of a secondary dilution, spiking of separate aliquots for uranium and thorium isotope dilution measurements, and purification of uranium and thorium aliquots for mass spectrometry. This SOP may be applied to uranium samples of unknown purity as in a nuclear forensic investigation, and also to well-characterized samples such as, for example, U{sub 3}O{sub 8} and U-metal certified reference materials. The sample of uranium is transferred to a quartz or PFA vial, concentrated nitric acid is added and the sample is heated on a hotplate at approximately 100 C for several hours until it dissolves. The sample solution is diluted with water to make the solution approximately 4 M HNO{sub 3} and hydrofluoric acid is added to make it 0.05 M HF. A secondary dilution of the primary uranium solution is prepared. Separate aliquots for uranium and thorium isotope dilution measurements are taken and spiked with {sup 233}U and {sup 229}Th, respectively. The spiked aliquot for uranium isotope dilution analysis is purified using EiChrom UTEVA resin. The spiked aliquot for thorium isotope dilution analysis is purified by, first, a 1.8 mL AG1x8 resin bed in 9 M HCl on which U adsorbs and Th passes through; second, adsorbing Th on a 1 mL AG1x8 resin bed in 8 M HNO{sub 3} and then eluting it with 9 M HCl followed by 0.1 M HCl + 0.005 M HF; and third, by passing the Th through a final 1.0 mL AG1x8 resin bed in 9 M HCl. The mass spectrometry is performed using the procedure 'Th and U Mass Spectrometry for {sup 230}Th-{sup 234}U Age Dating'.

  4. Technological advances in the University of Washington accelerator mass spectrometry system

    SciTech Connect (OSTI)

    Farwell, G.W.; Grootes, P.M.; Leach, D.D.; Schmidt, F.H.

    1983-01-01

    During the past year we have continued to work toward greater stability and flexibility in nearly all elements of our accelerator mass spectrometry (AMS) system, which is based upon an FN tandem Van de Graaff accelerator, and have carried out measurements of /sup 14/C//sup 12/C and /sup 10/Be//sup 9/Be isotopic abundance ratios in natural samples. The principal recent developments and improvements in the accelerator system and in our sample preparation techniques for carbon beryllium are discussed, and the results of a study of /sup 10/Be cross-contamination of beryllium samples in the sputter ion source are presented.

  5. Analysis of volatile organic compounds in groundwater samples by gas chromatography-mass spectrometry

    SciTech Connect (OSTI)

    Bernhardt, J.

    1995-08-23

    The Savannah River Site contains approximately 1500 monitoring wells from which groundwater samples are collected. Many of these samples are sent off-site for various analyses, including the determination of trace volatile organic compounds (VOCs). This report describes accomplishments that have been made during the past year which will ultimately allow VOC analysis to be performed on-site using gas chromatography-mass spectrometry. Through the use of the on-site approach, it is expected that there will be a substantial cost savings. This approach will also provide split-sample analysis capability which can serve as a quality control measure for off-site analysis.

  6. Comparison of FTIR and Particle Mass Spectrometry for the Measurement of Paticulate Organic Nitrates

    SciTech Connect (OSTI)

    Bruns, Emily; Perraud, Veronique; Zelenyuk, Alla; Ezell, Michael J.; Johnson, Stanley N.; Yu, Yong; Imre, D.; Finlayson-Pitts, Barbara J.; Alexander, M. L.

    2010-02-01

    While multifunctional organic nitrates are formed during the atmospheric oxidation of volatile organic compounds, relatively little is known about their signatures in particle mass spectrometers. High resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) was applied to NH4NO3, NaNO3 and isosorbide 5-mononitrate (IMN) particles, and to secondary organic aerosol (SOA) from NO3 radical reactions at 22 C and 1 atm in air with and pinene, 3-carene, limonene and isoprene. For comparison, single particle laser ablation mass spectra (SPLAT II) were also obtained for IMN and SOA from the pinene reaction. The mass spectra of all particles exhibit significant intensity at m/z 30, and for the SOA, weak peaks corresponding to various organic fragments containing nitrogen [CxHyNzOa]+ were identified using HR-ToF-AMS. The NO+/NO2+ ratios from HR-ToF-AMS were 10-15 for IMN and the SOA from the and pinene, 3-carene and limonene reactions, ~5 for the isoprene reaction, 2.4 for NH4NO3 and 80 for NaNO3. The N/H ratios from HR-ToF-AMS for the SOA were smaller by a factor of 2 to 4 than the -ONO2/C-H ratios measured using FTIR on particles impacted on ZnSe windows. While the NO+/NO2+ ratio may provide a generic indication of organic nitrates under some conditions, specific identification of particulate organic nitrates awaits further development of particle mass spectrometry techniques.

  7. APT mass spectrometry and SEM data for CdTe solar cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Chen; Paudel, Naba R.; Yan, Yanfa; Pennycook, Stephen J.; Poplawsky, Jonathan D.; Guo, Wei

    2016-03-16

    Atom probe tomography (APT) data acquired from a CAMECA LEAP 4000 XHR for the CdS/CdTe interface for a non-CdCl2 treated CdTe solar cell as well as the mass spectrum of an APT data set including a GB in a CdCl2-treated CdTe solar cell are presented. Scanning electron microscopy (SEM) data showing the evolution of sample preparation for APT and scanning transmission electron microscopy (STEM) electron beam induced current (EBIC) are also presented. As a result, these data show mass spectrometry peak decomposition of Cu and Te within an APT dataset, the CdS/CdTe interface of an untreated CdTe solar cell, preparationmore » of APT needles from the CdS/CdTe interface in superstrate grown CdTe solar cells, and the preparation of a cross-sectional STEM EBIC sample.« less

  8. Mass Spectrometry and Fourier Transform Infrared Spectroscopy for Analysis of Biological Materials

    SciTech Connect (OSTI)

    Anderson, Timothy J.

    2014-12-01

    Time-of-flight mass spectrometry along with statistical analysis was utilized to study metabolic profiles among rats fed resistant starch (RS) diets. Fischer 344 rats were fed four starch diets consisting of 55% (w/w, dbs) starch. A control starch diet consisting of corn starch was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. A subgroup received antibiotic treatment to determine if perturbations in the gut microbiome were long lasting. A second subgroup was treated with azoxymethane (AOM), a carcinogen. At the end of the eight week study, cecal and distal-colon contents samples were collected from the sacrificed rats. Metabolites were extracted from cecal and distal colon samples into acetonitrile. The extracts were then analyzed on an accurate-mass time-of-flight mass spectrometer to obtain their metabolic profile. The data were analyzed using partial least-squares discriminant analysis (PLS-DA). The PLS-DA analysis utilized a training set and verification set to classify samples within diet and treatment groups. PLS-DA could reliably differentiate the diet treatments for both cecal and distal colon samples. The PLS-DA analyses of the antibiotic and no antibiotic treated subgroups were well classified for cecal samples and modestly separated for distal-colon samples. PLS-DA analysis had limited success separating distal colon samples for rats given AOM from those not treated; the cecal samples from AOM had very poor classification. Mass spectrometry profiling coupled with PLS-DA can readily classify metabolite differences among rats given RS diets.

  9. Advanced solvent based methods for molecular characterization of soil organic matter by high-resolution mass spectrometry

    SciTech Connect (OSTI)

    Tfaily, Malak M.; Chu, Rosalie K.; Tolic, Nikola; Roscioli, Kristyn M.; Anderton, Christopher R.; Pasa-Tolic, Ljiljana; Robinson, Errol W.; Hess, Nancy J.

    2015-05-19

    Soil organic matter (SOM) a complex, heterogeneous mixture of above and belowground plant litter and animal and microbial residues at various degrees of decomposition, is a key reservoir for carbon (C) and nutrient biogeochemical cycling in soil based ecosystems. A limited understanding of the molecular composition of SOM limits the ability to routinely decipher chemical processes within soil and predict accurately how terrestrial carbon fluxes will response to changing climatic conditions and land use. To elucidate the molecular-level structure of SOM, we selectively extracted a broad range of intact SOM compounds by a combination of different organic solvents from soils with a wide range of C content. Our use of Electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and a suite of solvents with varying polarity significantly expands the inventory of the types of organic molecules present in soils. Specifically, we found that hexane is selective for lipid-like compounds with very low O:C ratios; water was selective for carbohydrates with high O:C ratios; acetonitrile preferentially extracts lignin, condensed structures, and tannin poly phenolic compounds with O:C > 0.5; methanol has higher selectivity towards compounds characterized with low O:C < 0.5; and hexane, MeOH, ACN and water solvents increase the number and types of organic molecules extracted from soil for a broader range of chemically diverse soil types. Our study of SOM molecules by ESI-FTICR MS revealed new insight into the molecular-level complexity of organics contained in soils.

  10. Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation

    SciTech Connect (OSTI)

    Golan, Amir; Ahmed, Musahid

    2012-01-01

    Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics.[1-4] Fundamental studies of photoionization processes of biomolecules provide information about electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water.[1, 5-9] We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-methyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline[10] located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds[1]. Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations[11, 12]. By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn, explain

  11. Cross-Linking and Mass Spectrometry Methodologies to Facilitate Structural Biology: Finding a Path through the Maze

    SciTech Connect (OSTI)

    Merkley, Eric D.; Cort, John R.; Adkins, Joshua N.

    2013-09-01

    Multiprotein complexes, rather than individual proteins, make up a large part of the biological macromolecular machinery of a cell. Understanding the structure and organization of these complexes is critical to understanding cellular function. Chemical cross-linking coupled with mass spectrometry is emerging as a complementary technique to traditional structural biology methods and can provide low-resolution structural information for a multitude of purposes, such as distance constraints in computational modeling of protein complexes. In this review, we discuss the experimental considerations for successful application of chemical cross-linking-mass spectrometry in biological studies and highlight three examples of such studies from the recent literature. These examples (as well as many others) illustrate the utility of a chemical cross-linking-mass spectrometry approach in facilitating structural analysis of large and challenging complexes.

  12. High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry

    SciTech Connect (OSTI)

    Jill Wisnewski Ferguson

    2006-08-09

    The inductively coupled plasma (ICP) is an atmospheric pressure ionization source. Traditionally, the plasma is sampled via a sampler cone. A supersonic jet develops behind the sampler, and this region is pumped down to a pressure of approximately one Torr. A skimmer cone is located inside this zone of silence to transmit ions into the mass spectrometer. The position of the sampler and skimmer cones relative to the initial radiation and normal analytical zones of the plasma is key to optimizing the useful analytical signal [1]. The ICP both atomizes and ionizes the sample. Polyatomic ions form through ion-molecule interactions either in the ICP or during ion extraction [l]. Common polyatomic ions that inhibit analysis include metal oxides (MO{sup +}), adducts with argon, the gas most commonly used to make up the plasma, and hydride species. While high resolution devices can separate many analytes from common interferences, this is done at great cost in ion transmission efficiency--a loss of 99% when using high versus low resolution on the same instrument [2]. Simple quadrupole devices, which make up the bulk of ICP-MS instruments in existence, do not present this option. Therefore, if the source of polyatomic interferences can be determined and then manipulated, this could potentially improve the figures of merit on all ICP-MS devices, not just the high resolution devices often utilized to study polyatomic interferences.

  13. Analysis of fission gas release kinetics by on-line mass spectrometry

    SciTech Connect (OSTI)

    Zerega, Y.; Reynard-Carette, C.; Parrat, D.; Carette, M.; Brkic, B.; Lyoussi, A.; Bignan, G.; Janulyte, A.; Andre, J.; Pontillon, Y.; Ducros, G.; Taylor, S.

    2011-07-01

    The release of fission gas (Xe and Kr) and helium out of nuclear fuel materials in normal operation of a nuclear power reactor can constitute a strong limitation of the fuel lifetime. Moreover, radioactive isotopes of Xe and Kr contribute significantly to the global radiological source term released in the primary coolant circuit in case of accidental situations accompanied by fuel rod loss of integrity. As a consequence, fission gas release investigation is of prime importance for the nuclear fuel cycle economy, and is the driven force of numerous R and D programs. In this domain, for solving current fuel behavior understanding issues, preparing the development of new fuels (e.g. for Gen IV power systems) and for improving the modeling prediction capability, there is a marked need for innovations in the instrumentation field, mainly for: . Quantification of very low fission gas concentrations, released from fuel sample and routed in sweeping lines. Monitoring of quick gas release variations by quantification of elementary release during a short period of time. Detection of a large range of atomic masses (e.g. H{sub 2}, HT, He, CO, CO{sub 2}, Ne, Ar, Kr, Xe), together with a performing separation of isotopes for Xe and Kr elements. Coupling measurement of stable and radioactive gas isotopes, by using in parallel mass spectrometry and gamma spectrometry techniques. To fulfill these challenging needs, a common strategy for analysis equipment implementation has been set up thanks to a recently launched collaboration between the CEA and the Univ. of Provence, with the technological support of the Liverpool Univ.. It aims at developing a chronological series of mass spectrometer devices based upon mass filter and 2D/3D ion traps with Fourier transform operating mode and having increasing levels of performances to match the previous challenges for out-of pile and in-pile experiments. The final objective is to install a high performance online mass spectrometer coupled to

  14. Detecting and Removing Data Artifacts in Hadamard Transform Ion Mobility-Mass Spectrometry Measurements

    SciTech Connect (OSTI)

    Prost, Spencer A.; Crowell, Kevin L.; Baker, Erin Shammel; Ibrahim, Yehia M.; Clowers, Brian H.; Monroe, Matthew E.; Anderson, Gordon A.; Smith, Richard D.; Payne, Samuel H.

    2014-12-01

    Applying Hadamard transform multiplexing to ion mobility separations (IMS) can significantly improve the signal-to-noise ratio and throughput for IMS coupled mass spectrometry (MS) measurements by increasing the ion utilization efficiency. However, it has been determined that both fluctuations in ion intensity as well as spatial shifts in the multiplexed data lower the signal-to-noise ratios and appear as noise in downstream processing of the data. To address this problem, we have developed a novel algorithm that discovers and eliminates data artifacts. The algorithm uses knowledge of the true signal peaks derived from the encoded data and allows for both artifacts and noise to be removed with high confidence, decreasing the likelihood of false identifications in subsequent data processing. The result is that IMS-MS can be applied to increase measurement sensitivity while avoiding artifacts that have previously limited its utility.

  15. Synchrotron photoionization mass spectrometry study of intermediates in fuel-rich 1,2-dimethoxyethane flame

    SciTech Connect (OSTI)

    Lin, Z. K.; Han, D. L.; Li, S. F.; Li, Y. Y.; Yuan, T.

    2009-04-21

    Intermediates in a fuel-rich premixed laminar 1,2-dimethoxyethane (DME) flame are studied by molecular beam mass spectrometry combined with tunable synchrotron vacuum ultraviolet photoionization. About 30 intermediate species are identified in the present work, and their mole fraction profiles are evaluated. The experimental results show that the formations of intermediates, both hydrocarbons and oxygenated hydrocarbons, are closely linked to the structure of fuel, which is consistent with the previous reports. Species produced from H atom abstraction and beta scission of DME usually have much higher concentrations than others. The oxygen atoms in DME are considered to act as partitions of the primary intermediates; therefore farther reactions among these primary intermediates are difficult to occur, resulting in absence of most large intermediate species.

  16. A Hybrid Approach to Protein Differential Expression in Mass Spectrometry-Based Proteomics

    SciTech Connect (OSTI)

    Wang, Xuan; Anderson, Gordon A.; Smith, Richard D.; Dabney, Alan R.

    2012-04-19

    Motivation: Quantitative mass spectrometry-based proteomics involves statistical inference on protein abundance, based on the intensities of each protein's associated spectral peaks. However, typical MS-based proteomics data sets have substantial proportions of missing observations, due at least in part to censoring of low intensities. This complicates intensity-based differential expression analysis. Results: We outline a statistical method for protein differential expression, based on a simple Binomial likelihood. By modeling peak intensities as binary, in terms of 'presence/ absence,' we enable the selection of proteins not typically amendable to quantitative analysis; e.g., 'one-state' proteins that are present in one condition but absent in another. In addition, we present an analysis protocol that combines quantitative and presence/ absence analysis of a given data set in a principled way, resulting in a single list of selected proteins with a single associated FDR.

  17. Detonation reaction steps frozen by free expansion and analyzed by mass spectrometry

    SciTech Connect (OSTI)

    Greiner, N.R.; Fry, H.A.; Blais, N.C.; Engelke, R.P.

    1993-05-01

    Detonation reactions in small pellets of explosive are frozen by free expansion into a large vacuum chamber and analyzed by time-of-flight mass spectrometry. Sensitive explosives like PETN, RDX, and HMX show rapidly evolving reaction zones and mostly simple products like H{sub 2}O, CO, N{sub 2}, and CO{sub 2}. Less sensitive explosives like TATB, HNS, and TNT show slower evolution of the reaction zone, and more complex products in addition to the simple ones seen in PETN. Isotopic substitution shows that the more complex products contain moderate amounts of NH{sub 3}, HCN, NO, HNCO, and NO{sub 2}. Other observations include polymerization of aromatic explosive molecules, adducts to the explosive molecules, and explosive molecules with functional groups missing. The more complex products are reservoirs of unreleased energy that may affect performance.

  18. Detonation reaction steps frozen by free expansion and analyzed by mass spectrometry

    SciTech Connect (OSTI)

    Greiner, N.R.; Fry, H.A.; Blais, N.C.; Engelke, R.P.

    1993-01-01

    Detonation reactions in small pellets of explosive are frozen by free expansion into a large vacuum chamber and analyzed by time-of-flight mass spectrometry. Sensitive explosives like PETN, RDX, and HMX show rapidly evolving reaction zones and mostly simple products like H[sub 2]O, CO, N[sub 2], and CO[sub 2]. Less sensitive explosives like TATB, HNS, and TNT show slower evolution of the reaction zone, and more complex products in addition to the simple ones seen in PETN. Isotopic substitution shows that the more complex products contain moderate amounts of NH[sub 3], HCN, NO, HNCO, and NO[sub 2]. Other observations include polymerization of aromatic explosive molecules, adducts to the explosive molecules, and explosive molecules with functional groups missing. The more complex products are reservoirs of unreleased energy that may affect performance.

  19. Laser desorption time-of-flight mass spectrometry of ultraviolet photo-processed ices

    SciTech Connect (OSTI)

    Paardekooper, D. M. Bossa, J.-B.; Isokoski, K.; Linnartz, H.

    2014-10-01

    A new ultra-high vacuum experiment is described that allows studying photo-induced chemical processes in interstellar ice analogues. MATRICES - a Mass Analytical Tool to study Reactions in Interstellar ICES applies a new concept by combining laser desorption and time-of-flight mass spectrometry with the ultimate goal to characterize in situ and in real time the solid state evolution of organic compounds upon UV photolysis for astronomically relevant ice mixtures and temperatures. The performance of the experimental setup is demonstrated by the kinetic analysis of the different photoproducts of pure methane (CH?) ice at 20 K. A quantitative approach provides formation yields of several new species with up to four carbon atoms. Convincing evidence is found for the formation of even larger species. Typical mass resolutions obtained range from M/?M ~320 to ~400 for CH? and argon, respectively. Additional tests show that the typical detection limit (in monolayers) is ?0.02 ML, substantially more sensitive than the regular techniques used to investigate chemical processes in interstellar ices.

  20. Structural Analysis of a Highly Glycosylated and Unliganded gp120-Based Antigen Using Mass Spectrometry

    SciTech Connect (OSTI)

    L Wang; Y Qin; S Ilchenko; J Bohon; W Shi; M Cho; K Takamoto; M Chance

    2011-12-31

    Structural characterization of the HIV-1 envelope protein gp120 is very important for providing an understanding of the protein's immunogenicity and its binding to cell receptors. So far, the crystallographic structure of gp120 with an intact V3 loop (in the absence of a CD4 coreceptor or antibody) has not been determined. The third variable region (V3) of the gp120 is immunodominant and contains glycosylation signatures that are essential for coreceptor binding and entry of the virus into T-cells. In this study, we characterized the structure of the outer domain of gp120 with an intact V3 loop (gp120-OD8) purified from Drosophila S2 cells utilizing mass spectrometry-based approaches. We mapped the glycosylation sites and calculated the glycosylation occupancy of gp120-OD8; 11 sites from 15 glycosylation motifs were determined as having high-mannose or hybrid glycosylation structures. The specific glycan moieties of nine glycosylation sites from eight unique glycopeptides were determined by a combination of ECD and CID MS approaches. Hydroxyl radical-mediated protein footprinting coupled with mass spectrometry analysis was employed to provide detailed information about protein structure of gp120-OD8 by directly identifying accessible and hydroxyl radical-reactive side chain residues. Comparison of gp120-OD8 experimental footprinting data with a homology model derived from the ligated CD4-gp120-OD8 crystal structure revealed a flexible V3 loop structure in which the V3 tip may provide contacts with the rest of the protein while residues in the V3 base remain solvent accessible. In addition, the data illustrate interactions between specific sugar moieties and amino acid side chains potentially important to the gp120-OD8 structure.

  1. Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS)

    SciTech Connect (OSTI)

    Aerosol Dynamics Inc; Aerodyne Research, Inc.,; Tofwerk AG, Thun; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Doug R.; Goldstein, Allen H.

    2011-09-13

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved based on tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally-relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. The classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  2. Kinetics of laser-pulse vaporization of uranium carbide by mass spectrometry. [LMFBR

    SciTech Connect (OSTI)

    Tehranian, F.

    1983-06-01

    The kinetics of uranium carbide vaporization in the temperature range 3000 K to 5200 K was studied using a Nd-glass laser with peak power densities from 1.6 x 10/sup 5/ to 4.0 x 10/sup 5/ watts/cm/sup 2/. The vapor species U, UC/sub 2/, C/sub 1/ and C/sub 3/ were detected and analyzed by a quadrupole mass spectrometer. From the mass spectrometer signals number densities of the various species in the ionizer were obtained as functions of time. The surface of the irradiated uranium carbide was examined by scanning electron microscope and the depth profile of the crater was obtained. In order to aid analysis of the data, the heat conduction and species diffusion equations for the solid (or liquid) were solved numerically by a computer code to obtain the temperature and composition transients during laser heating. A sensitivity analysis was used to study the effect of uncertainties in the input parameters on the computed surface temperatures.

  3. Spatially tracking 13C labeled substrate (bicarbonate) accumulation in microbial communities using laser ablation isotope ratio mass spectrometry

    SciTech Connect (OSTI)

    Moran, James J.; Doll, Charles G.; Bernstein, Hans C.; Renslow, Ryan S.; Cory, Alexandra B.; Hutchison, Janine R.; Lindemann, Stephen R.; Fredrickson, Jim K.

    2014-08-25

    This is a manuscript we would like to submit for publication in Environmental Microbiology Reports. This manuscript contains a description of a laser ablation isotope ratio mass spectrometry methodology developed at PNNL and applied to a microbial system at a PNNL project location – Hot Lake, Washington. I will submit a word document containing the entire manuscript with this Erica input request form.

  4. Topographical and Chemical Imaging of a Phase Separated Polymer Using a Combined Atomic Force Microscopy/Infrared Spectroscopy/Mass Spectrometry Platform

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tai, Tamin; Karácsony, Orsolya; Bocharova, Vera; Van Berkel, Gary J.; Kertesz, Vilmos

    2016-02-18

    This article describes how the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometry imaging platform was demonstrated for the acquisition and correlation of nanoscale sample surface topography and chemical images based on infrared spectroscopy and mass spectrometry.

  5. New insights into low-temperature oxidation of propane from synchrotron photoionization mass spectrometry and multi-scale informatics modeling

    SciTech Connect (OSTI)

    Welz, Oliver; Burke, Michael P.; Antonov, Ivan O.; Goldsmith, C. Franklin; Savee, John David; Osborn, David L.; Taatjes, Craig A.; Klippenstein, Stephen J.; Sheps, Leonid

    2015-04-10

    We studied low-temperature propane oxidation at P = 4 Torr and T = 530, 600, and 670 K by time-resolved multiplexed photoionization mass spectrometry (MPIMS), which probes the reactants, intermediates, and products with isomeric selectivity using tunable synchrotron vacuum UV ionizing radiation. The oxidation is initiated by pulsed laser photolysis of oxalyl chloride, (COCl)2, at 248 nm, which rapidly generates a ~1:1 mixture of 1-propyl (n-propyl) and 2-propyl (i-propyl) radicals via the fast Cl + propane reaction. At all three temperatures, the major stable product species is propene, formed in the propyl + O2 reactions by direct HO2 elimination from both n- and i-propyl peroxy radicals. The experimentally derived propene yields relative to the initial concentration of Cl atoms are (20 4)% at 530 K, (55 11)% at 600 K, and (86 17)% at 670 K at a reaction time of 20 ms. The lower yield of propene at low temperature reflects substantial formation of propyl peroxy radicals, which do not completely decompose on the experimental time scale. In addition, C3H6O isomers methyloxirane, oxetane, acetone, and propanal are detected as minor products. Our measured yields of oxetane and methyloxirane, which are coproducts of OH radicals, suggest a revision of the OH formation pathways in models of low-temperature propane oxidation. The experimental results are modeled and interpreted using a multiscale informatics approach, presented in detail in a separate publication (Burke, M. P.; Goldsmith, C. F.; Klippenstein, S. J.; Welz, O.; Huang H.; Antonov I. O.; Savee J. D.; Osborn D. L.; Zdor, J.; Taatjes, C. A.; Sheps, L. Multiscale Informatics for Low-Temperature Propane Oxidation: Further Complexities in Studies of Complex Reactions. J. Phys. Chem A. 2015, DOI: 10.1021/acs.jpca.5b01003). Additionally, we found that the model predicts the time profiles and yields of the experimentally observed primary products well, and

  6. New insights into low-temperature oxidation of propane from synchrotron photoionization mass spectrometry and multi-scale informatics modeling

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Welz, Oliver; Burke, Michael P.; Antonov, Ivan O.; Goldsmith, C. Franklin; Savee, John David; Osborn, David L.; Taatjes, Craig A.; Klippenstein, Stephen J.; Sheps, Leonid

    2015-04-10

    We studied low-temperature propane oxidation at P = 4 Torr and T = 530, 600, and 670 K by time-resolved multiplexed photoionization mass spectrometry (MPIMS), which probes the reactants, intermediates, and products with isomeric selectivity using tunable synchrotron vacuum UV ionizing radiation. The oxidation is initiated by pulsed laser photolysis of oxalyl chloride, (COCl)2, at 248 nm, which rapidly generates a ~1:1 mixture of 1-propyl (n-propyl) and 2-propyl (i-propyl) radicals via the fast Cl + propane reaction. At all three temperatures, the major stable product species is propene, formed in the propyl + O2 reactions by direct HO2 elimination frommore » both n- and i-propyl peroxy radicals. The experimentally derived propene yields relative to the initial concentration of Cl atoms are (20 ± 4)% at 530 K, (55 ± 11)% at 600 K, and (86 ± 17)% at 670 K at a reaction time of 20 ms. The lower yield of propene at low temperature reflects substantial formation of propyl peroxy radicals, which do not completely decompose on the experimental time scale. In addition, C3H6O isomers methyloxirane, oxetane, acetone, and propanal are detected as minor products. Our measured yields of oxetane and methyloxirane, which are coproducts of OH radicals, suggest a revision of the OH formation pathways in models of low-temperature propane oxidation. The experimental results are modeled and interpreted using a multiscale informatics approach, presented in detail in a separate publication (Burke, M. P.; Goldsmith, C. F.; Klippenstein, S. J.; Welz, O.; Huang H.; Antonov I. O.; Savee J. D.; Osborn D. L.; Zádor, J.; Taatjes, C. A.; Sheps, L. Multiscale Informatics for Low-Temperature Propane Oxidation: Further Complexities in Studies of Complex Reactions. J. Phys. Chem A. 2015, DOI: 10.1021/acs.jpca.5b01003). Additionally, we found that the model predicts the time profiles and yields of the experimentally observed primary products well, and shows satisfactory agreement for products

  7. New insights into low-temperature oxidation of propane from synchrotron photoionization mass spectrometry and multi-scale informatics modeling

    SciTech Connect (OSTI)

    Welz, Oliver; Burke, Michael P.; Antonov, Ivan O.; Goldsmith, C. Franklin; Savee, John David; Osborn, David L.; Taatjes, Craig A.; Klippenstein, Stephen J.; Sheps, Leonid

    2015-04-10

    We studied low-temperature propane oxidation at P = 4 Torr and T = 530, 600, and 670 K by time-resolved multiplexed photoionization mass spectrometry (MPIMS), which probes the reactants, intermediates, and products with isomeric selectivity using tunable synchrotron vacuum UV ionizing radiation. The oxidation is initiated by pulsed laser photolysis of oxalyl chloride, (COCl)2, at 248 nm, which rapidly generates a ~1:1 mixture of 1-propyl (n-propyl) and 2-propyl (i-propyl) radicals via the fast Cl + propane reaction. At all three temperatures, the major stable product species is propene, formed in the propyl + O2 reactions by direct HO2 elimination from both n- and i-propyl peroxy radicals. The experimentally derived propene yields relative to the initial concentration of Cl atoms are (20 ± 4)% at 530 K, (55 ± 11)% at 600 K, and (86 ± 17)% at 670 K at a reaction time of 20 ms. The lower yield of propene at low temperature reflects substantial formation of propyl peroxy radicals, which do not completely decompose on the experimental time scale. In addition, C3H6O isomers methyloxirane, oxetane, acetone, and propanal are detected as minor products. Our measured yields of oxetane and methyloxirane, which are coproducts of OH radicals, suggest a revision of the OH formation pathways in models of low-temperature propane oxidation. The experimental results are modeled and interpreted using a multiscale informatics approach, presented in detail in a separate publication (Burke, M. P.; Goldsmith, C. F.; Klippenstein, S. J.; Welz, O.; Huang H.; Antonov I. O.; Savee J. D.; Osborn D. L.; Zádor, J.; Taatjes, C. A.; Sheps, L. Multiscale Informatics for Low-Temperature Propane Oxidation: Further Complexities in Studies of Complex Reactions. J. Phys. Chem A. 2015, DOI: 10.1021/acs.jpca.5b01003). Additionally, we found that the model predicts the time profiles and yields of the experimentally observed primary products well

  8. Detection of Chemical/Biological Agents and Stimulants using Quadrupole Ion Trap Mass Spectrometry

    SciTech Connect (OSTI)

    Harmon, S.H.; Hart, K.J.; Vass, A.A.; Wise, M.B.; Wolf, D.A.

    1999-06-14

    Detection of Chemical/Biological Agents and Simulants A new detector for chemical and biological agents is being developed for the U. S. Army under the Chemical and Biological Mass Spectrometer Block II program. The CBMS Block II is designed to optimize detection of both chemical and biological agents through the use of direct sampling inlets [I], a multi- ported sampling valve and a turbo- based vacuum system to support chemical ionization. Unit mass resolution using air as the buffer gas [2] has been obtained using this design. Software to control the instrument and to analyze the data generated from the instrument has also been newly developed. Detection of chemical agents can be accomplished. using the CBMS Block II design via one of two inlets - a l/ I 6'' stainless steel sample line -Chemical Warfare Air (CW Air) or a ground probe with enclosed capillary currently in use by the US Army - CW Ground. The Block II design is capable of both electron ionization and chemical ionization. Ethanol is being used as the Cl reagent based on a study indicating best performance for the Biological Warfare (BW) detection task (31). Data showing good signal to noise for 500 pg of methyl salicylate injected into the CW Air inlet, 50 ng of dimethylmethylphosphonate exposed to the CW Ground probe and 5 ng of methyl stearate analyzed using the pyrolyzer inlet were presented. Biological agents are sampled using a ''bio-concentrator'' unit that is designed to concentrate particles in the low micron range. Particles are collected in the bottom of a quartz pyrolyzer tube. An automated injector is being developed to deliver approximately 2 pL of a methylating reagent, tetramethylamonium- hydroxide to 'the collected particles. Pyrolysis occurs by rapid heating to ca. 55OOC. Biological agents are then characterized by their fatty acid methyl ester profiles and by other biomarkers. A library of ETOH- Cl/ pyrolysis MS data of microorganisms used for a recently published study [3] has been

  9. Femtosecond laser ablation-based mass spectrometry. An ideal tool for stoichiometric analysis of thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    LaHaye, Nicole L.; Kurian, Jose; Diwakar, Prasoon K.; Alff, Lambert; Harilal, Sivanandan S.

    2015-08-19

    An accurate and routinely available method for stoichiometric analysis of thin films is a desideratum of modern materials science where a material’s properties depend sensitively on elemental composition. We thoroughly investigated femtosecond laser ablation-inductively coupled plasma-mass spectrometry (fs-LA-ICP-MS) as an analytical technique for determination of the stoichiometry of thin films down to the nanometer scale. The use of femtosecond laser ablation allows for precise removal of material with high spatial and depth resolution that can be coupled to an ICP-MS to obtain elemental and isotopic information. We used molecular beam epitaxy-grown thin films of LaPd(x)Sb2 and T´-La2CuO4 to demonstrate themore » capacity of fs-LA-ICP-MS for stoichiometric analysis and the spatial and depth resolution of the technique. Here we demonstrate that the stoichiometric information of thin films with a thickness of ~10 nm or lower can be determined. Furthermore, our results indicate that fs-LA-ICP-MS provides precise information on the thin film-substrate interface and is able to detect the interdiffusion of cations.« less

  10. Systematic Optimization of Long Gradient Chromatography Mass Spectrometry for Deep Analysis of Brain Proteome

    SciTech Connect (OSTI)

    Wang, Hong; Yang, Yanling; Li, Yuxin; Bai, Bing; Wang, Xusheng; Tan, Haiyan; Liu, Tao; Beach, Thomas G.; Peng, Junmun; Wu, Zhiping

    2015-02-06

    Development of high resolution liquid chromatography (LC) is essential for improving the sensitivity and throughput of mass spectrometry (MS)-based proteomics. Here we present systematic optimization of a long gradient LC-MS/MS platform to enhance protein identification from a complex mixture. The platform employed an in-house fabricated, reverse phase column (100 μm x 150 cm) coupled with Q Exactive MS. The column was capable of achieving a peak capacity of approximately 700 in a 720 min gradient of 10-45% acetonitrile. The optimal loading level was about 6 micrograms of peptides, although the column allowed loading as many as 20 micrograms. Gas phase fractionation of peptide ions further increased the number of peptide identification by ~10%. Moreover, the combination of basic pH LC pre-fractionation with the long gradient LC-MS/MS platform enabled the identification of 96,127 peptides and 10,544 proteins at 1% protein false discovery rate in a postmortem brain sample of Alzheimer’s disease. As deep RNA sequencing of the same specimen suggested that ~16,000 genes were expressed, current analysis covered more than 60% of the expressed proteome. Further improvement strategies of the LC/LC-MS/MS platform were also discussed.

  11. Indexing Permafrost Soil Organic Matter Degradation Using High-Resolution Mass Spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mann, Benjamin F.; Chen, Hongmei; Herndon, Elizabeth M.; Chu, Rosalie K.; Tolic, Nikola; Portier, Evan F.; Roy Chowdhury, Taniya; Robinson, Errol W.; Callister, Stephen J.; Wullschleger, Stan D.; et al

    2015-06-12

    Microbial degradation of soil organic matter (SOM) is a key process for terrestrial carbon cycling, although the molecular details of these transformations remain unclear. This study reports the application of ultrahigh resolution mass spectrometry to profile the molecular composition of SOM and its degradation during a simulated warming experiment. A soil sample, collected near Barrow, Alaska, USA, was subjected to a 40-day incubation under anoxic conditions and analyzed before and after the incubation to determine changes of SOM composition. A CHO index based on molecular C, H, and O data was utilized to codify SOM components according to their observedmore » degradation potentials. Compounds with a CHO index score between –1 and 0 in a water-soluble fraction (WSF) demonstrated high degradation potential, with a highest shift of CHO index occurred in the N-containing group of compounds, while similar stoichiometries in a base-soluble fraction (BSF) did not. Additionally, compared with the classical H:C vs O:C van Krevelen diagram, CHO index allowed for direct visualization of the distribution of heteroatoms such as N in the identified SOM compounds. We demonstrate that CHO index is useful not only in characterizing arctic SOM at the molecular level but also enabling quantitative description of SOM degradation, thereby facilitating incorporation of the high resolution MS datasets to future mechanistic models of SOM degradation and prediction of greenhouse gas emissions.« less

  12. Mass spectrometry footprinting reveals the structural rearrangements of cyanobacterial orange carotenoid protein upon light activation

    SciTech Connect (OSTI)

    Liu, Haijun; Zhang, Hao; King, Jeremy D.; Wolf, Nathan R.; Prado, Mindy; Gross, Michael L.; Blankenship, Robert E.

    2014-12-01

    The orange carotenoid protein (OCP), a member of the family of blue light photoactive proteins, is required for efficient photoprotection in many cyanobacteria. Photoexcitation of the carotenoid in the OCP results in structural changes within the chromophore and the protein to give an active red form of OCP that is required for phycobilisome binding and consequent fluorescence quenching. We characterized the light-dependent structural changes by mass spectrometry-based carboxyl footprinting and found that an α helix in the N-terminal extension of OCP plays a key role in this photoactivation process. Although this helix is located on and associates with the outside of the β-sheet core in the C-terminal domain of OCP in the dark, photoinduced changes in the domain structure disrupt this interaction. We propose that this mechanism couples light-dependent carotenoid conformational changes to global protein conformational dynamics in favor of functional phycobilisome binding, and is an essential part of the OCP photocycle.

  13. Femtosecond laser ablation-based mass spectrometry. An ideal tool for stoichiometric analysis of thin films

    SciTech Connect (OSTI)

    LaHaye, Nicole L.; Kurian, Jose; Diwakar, Prasoon K.; Alff, Lambert; Harilal, Sivanandan S.

    2015-08-19

    An accurate and routinely available method for stoichiometric analysis of thin films is a desideratum of modern materials science where a material’s properties depend sensitively on elemental composition. We thoroughly investigated femtosecond laser ablation-inductively coupled plasma-mass spectrometry (fs-LA-ICP-MS) as an analytical technique for determination of the stoichiometry of thin films down to the nanometer scale. The use of femtosecond laser ablation allows for precise removal of material with high spatial and depth resolution that can be coupled to an ICP-MS to obtain elemental and isotopic information. We used molecular beam epitaxy-grown thin films of LaPd(x)Sb2 and T´-La2CuO4 to demonstrate the capacity of fs-LA-ICP-MS for stoichiometric analysis and the spatial and depth resolution of the technique. Here we demonstrate that the stoichiometric information of thin films with a thickness of ~10 nm or lower can be determined. Furthermore, our results indicate that fs-LA-ICP-MS provides precise information on the thin film-substrate interface and is able to detect the interdiffusion of cations.

  14. Characterization of Interlayer Cs+ in Clay Samples Using Secondary Ion Mass Spectrometry with Laser Sample Modification

    SciTech Connect (OSTI)

    G. S. Groenewold; R. Avci; C. Karahan; K. Lefebre; R. V. Fox; M. M. Cortez; A. K. Gianotto; J. Sunner; W. L. Manner

    2004-04-01

    Ultraviolet laser irradiation was used to greatly enhance the secondary ion mass spectrometry (SIMS) detection of Cs+ adsorbed to soil consisting of clay and quartz. Imaging SIMS showed that the enhancement of the Cs+ signal was spatially heterogeneous: the intensity of the Cs+ peak was increased by factors up to 100 for some particles but not at all for others. Analysis of standard clay samples exposed to Cs+ showed a variable response to laser irradiation depending on the type of clay analyzed. The Cs+ abundance was significantly enhanced when Cs+-exposed montmorillonite was irradiated and then analyzed using SIMS, which contrasted with the behavior of Cs+-exposed kaolinite, which displayed no Cs+ enhancement. Exposed illitic clays displayed modest enhancement of Cs+ upon laser irradiation, intermediate between that of kaolinite and montmorillonite. The results for Cs+ were rationalized in terms of adsorption to interlayer sites within the montmorillonite, which is an expandable phyllosilicate. In these locations, Cs+ was not initially detectable using SIMS. Upon irradiation, Cs+ was thermally redistributed, which enabled detection using SIMS. Since neither the illite nor the kaolinite is an expandable clay, adsorption to inner-layer sites does not occur, and either modest or no laser enhancement of the Cs+ signal is observed. Laser irradiation also produced unexpected enhancement of Ti+ from illite and kaolinite clays that contained small quantities of Ti, which indicates the presence of microscopic titanium oxide phases in the clay materials.

  15. Hydrogen measurement during steam oxidation using coupled thermogravimetric analysis and quadrupole mass spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Parkison, Adam J.; Nelson, Andrew Thomas

    2016-01-11

    An analytical technique is presented with the goal of measuring reaction kinetics during steam oxidation reactions for three cases in which obtaining kinetics information often requires a prohibitive amount of time and cost. The technique presented relies on coupling thermogravimetric analysis (TGA) with a quantitative hydrogen measurement technique using quadrupole mass spectrometry (QMS). The first case considered is in differentiating between the kinetics of steam oxidation reactions and those for simultaneously reacting gaseous impurities such as nitrogen or oxygen. The second case allows one to independently measure the kinetics of oxide and hydride formation for systems in which both ofmore » these reactions are known to take place during steam oxidation. The third case deals with measuring the kinetics of formation for competing volatile and non-volatile oxides during certain steam oxidation reactions. In order to meet the requirements of the coupled technique, a methodology is presented which attempts to provide quantitative measurement of hydrogen generation using QMS in the presence of an interfering fragmentation species, namely water vapor. This is achieved such that all calibrations and corrections are performed during the TGA baseline and steam oxidation programs, making system operation virtually identical to standard TGA. Benchmarking results showed a relative error in hydrogen measurement of 5.7–8.4% following the application of a correction factor. Lastly, suggestions are made for possible improvements to the presented technique so that it may be better applied to the three cases presented.« less

  16. Indexing Permafrost Soil Organic Matter Degradation Using High-Resolution Mass Spectrometry

    SciTech Connect (OSTI)

    Mann, Benjamin F.; Chen, Hongmei; Herndon, Elizabeth M.; Chu, Rosalie K.; Tolic, Nikola; Portier, Evan F.; Roy Chowdhury, Taniya; Robinson, Errol W.; Callister, Stephen J.; Wullschleger, Stan D.; Graham, David E.; Liang, Liyuan; Gu, Baohua; Hui, Dafeng

    2015-06-12

    Microbial degradation of soil organic matter (SOM) is a key process for terrestrial carbon cycling, although the molecular details of these transformations remain unclear. This study reports the application of ultrahigh resolution mass spectrometry to profile the molecular composition of SOM and its degradation during a simulated warming experiment. A soil sample, collected near Barrow, Alaska, USA, was subjected to a 40-day incubation under anoxic conditions and analyzed before and after the incubation to determine changes of SOM composition. A CHO index based on molecular C, H, and O data was utilized to codify SOM components according to their observed degradation potentials. Compounds with a CHO index score between –1 and 0 in a water-soluble fraction (WSF) demonstrated high degradation potential, with a highest shift of CHO index occurred in the N-containing group of compounds, while similar stoichiometries in a base-soluble fraction (BSF) did not. Additionally, compared with the classical H:C vs O:C van Krevelen diagram, CHO index allowed for direct visualization of the distribution of heteroatoms such as N in the identified SOM compounds. We demonstrate that CHO index is useful not only in characterizing arctic SOM at the molecular level but also enabling quantitative description of SOM degradation, thereby facilitating incorporation of the high resolution MS datasets to future mechanistic models of SOM degradation and prediction of greenhouse gas emissions.

  17. OpenMSI: A High-Performance Web-Based Platform for Mass Spectrometry Imaging

    SciTech Connect (OSTI)

    Rubel, Oliver; Greiner, Annette; Cholia, Shreyas; Louie, Katherine; Bethel, E. Wes; Northen, Trent R.; Bowen, Benjamin P.

    2013-10-02

    Mass spectrometry imaging (MSI) enables researchers to directly probe endogenous molecules directly within the architecture of the biological matrix. Unfortunately, efficient access, management, and analysis of the data generated by MSI approaches remain major challenges to this rapidly developing field. Despite the availability of numerous dedicated file formats and software packages, it is a widely held viewpoint that the biggest challenge is simply opening, sharing, and analyzing a file without loss of information. Here we present OpenMSI, a software framework and platform that addresses these challenges via an advanced, high-performance, extensible file format and Web API for remote data access (http://openmsi.nersc.gov). The OpenMSI file format supports storage of raw MSI data, metadata, and derived analyses in a single, self-describing format based on HDF5 and is supported by a large range of analysis software (e.g., Matlab and R) and programming languages (e.g., C++, Fortran, and Python). Careful optimization of the storage layout of MSI data sets using chunking, compression, and data replication accelerates common, selective data access operations while minimizing data storage requirements and are critical enablers of rapid data I/O. The OpenMSI file format has shown to provide >2000-fold improvement for image access operations, enabling spectrum and image retrieval in less than 0.3 s across the Internet even for 50 GB MSI data sets. To make remote high-performance compute resources accessible for analysis and to facilitate data sharing and collaboration, we describe an easy-to-use yet powerful Web API, enabling fast and convenient access to MSI data, metadata, and derived analysis results stored remotely to facilitate high-performance data analysis and enable implementation of Web based data sharing, visualization, and analysis.

  18. Hydrothermal Liquefaction Oil and Hydrotreated Product from Pine Feedstock Characterized by Heteronuclear Two-Dimensional NMR Spectroscopy and FT-ICR Mass Spectrometry

    SciTech Connect (OSTI)

    Sudasinghe, Nilusha; Cort, John R.; Hallen, Richard T.; Olarte, Mariefel V.; Schmidt, Andrew J.; Schaub, Tanner

    2014-12-01

    Hydrothermal liquefaction (HTL) crude oil and hydrotreated product from pine tree farm waste (forest product residual, FPR) have been analyzed by direct infusion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) in both positive- and negative-ionization modes and high-resolution twodimensional heteronuclear 1H-13C NMR spectroscopy. FT-ICR MS resolves thousands of compounds in complex oils and provides unparalleled compositional details for individual molecules for identification of compound class (heteroatom content), type (number of rings plus double bonds to carbon or double bond equivalents (DBE) and carbon number (degree of alkylation). Heteronuclear 1H-13C NMR spectroscopy provides one-bond and multiple-bond correlations between pairs of 1H and 13C chemical shifts that are characteristic of different organic functional groups. Taken together this information provides a picture of the chemical composition of these oils. Pyrolysis crude oil product from pine wood was characterized for comparison. Generally, pyrolysis oil is comprised of a more diverse distribution of heteroatom classes with higher oxygen number relative to HTL oil as shown by both positive- and negative-ion ESI FT-ICR MS. A total of 300 N1, 594 O1 and 267 O2 compounds were observed as products of hydrotreatment. The relative abundance of N1O1, N1O2, N1O3, N2, N2O1, N2O2 and O3 compounds are reduced to different degrees after hydrotreatment and other higher heteroatom containing species (O4-O10, N1O4, N1O5 and N2O3) are completely removed by hydrotreatment.

  19. Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Canagaratna, M. R.; Jimenez, J. L.; Kroll, J. H.; Chen, Q.; Kessler, S. H.; Massoli, P.; Hildebrandt Ruiz, L.; Fortner, E.; Williams, L. R.; Wilson, K. R.; et al

    2015-01-12

    Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H : C), and organic mass-to-organic carbon (OM : OC) ratios, and of carbon oxidation state (OS C) for a vastly expanded laboratory data set of multifunctional oxidized OA standards. For the expanded standard data set, the method introduced by Aiken et al. (2008), which uses experimentally measured ion intensities at all ions to determinemore » elemental ratios (referred to here as "Aiken-Explicit"), reproduces known O : C and H : C ratio values within 20% (average absolute value of relative errors) and 12%, respectively. The more commonly used method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions (referred to here as "Aiken-Ambient"), reproduces O : C and H : C of multifunctional oxidized species within 28 and 14% of known values. The values from the latter method are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and especially H2O+ produced from many oxidized species. Combined AMS–vacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 °C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 °C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method uses specific ion

  20. Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Canagaratna, M. R.; Jimenez, J. L.; Kroll, J. H.; Chen, Q.; Kessler, S. H.; Massoli, P.; Hildebrandt Ruiz, L.; Fortner, E.; Williams, L. R.; Wilson, K. R.; et al

    2014-07-31

    Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H : C), organic mass-to-organic carbon (OM : OC), and carbon oxidation state (OSC) for a vastly expanded laboratory dataset of multifunctional oxidized OA standards. For the expanded standard dataset, the "Aiken-Explicit" method (Aiken et al., 2008), which uses experimentally measured ion intensities at all ions to determine elemental ratios, reproduces known molecular O :more » C and H : C ratio values within 20% (average absolute value of relative errors) and 12% respectively. The more commonly used "Aiken-Ambient" method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions, reproduces O : C and H : C of multifunctional oxidized species within 28% and 14% of known values. These values are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and H2O+ produced from many oxidized species. Combined AMS-vacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 °C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 °C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method reduces the systematic biases and reproduces O : C (H : C) ratios of individual oxidized standards within 28% (13

  1. Elemental ratio measurements of organic compounds using aerosol mass spectrometry: Characterization, improved calibration, and implications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Canagaratna, M. R.; Jimenez, J. L.; Kroll, J. H.; Chen, Q.; Kessler, S. H.; Massoli, P.; Ruiz, L. Hildebrandt; Fortner, E.; Williams, L. R.; Wilson, K. R.; et al

    2015-01-12

    Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H : C), and organic mass-to-organic carbon (OM : OC) ratios, and of carbon oxidation state (OS C) for a vastly expanded laboratory data set of multifunctional oxidized OA standards. For the expanded standard data set, the method introduced by Aiken et al. (2008), which uses experimentally measured ionmoreintensities at all ions to determine elemental ratios (referred to here as "Aiken-Explicit"), reproduces known O : C and H : C ratio values within 20% (average absolute value of relative errors) and 12%, respectively. The more commonly used method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions (referred to here as "Aiken-Ambient"), reproduces O : C and H : C of multifunctional oxidized species within 28 and 14% of known values. The values from the latter method are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and especially H2O+ produced from many oxidized species. Combined AMSvacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method uses specific ion

  2. DETERMINATION OF 237NP AND PU ISOTOPES IN LARGE SOIL SAMPLES BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY

    SciTech Connect (OSTI)

    Maxwell, S.

    2010-07-26

    A new method for the determination of {sup 237}Np and Pu isotopes in large soil samples has been developed that provides enhanced uranium removal to facilitate assay by inductively coupled plasma mass spectrometry (ICP-MS). This method allows rapid preconcentration and separation of plutonium and neptunium in large soil samples for the measurement of {sup 237}Np and Pu isotopes by ICP-MS. {sup 238}U can interfere with {sup 239}Pu measurement by ICP-MS as {sup 238}UH{sup +} mass overlap and {sup 237}Np via {sup 238}U peak tailing. The method provides enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then transferring Pu to DGA resin for additional purification. The decontamination factor for removal of uranium from plutonium for this method is greater than 1 x 10{sup 6}. Alpha spectrometry can also be applied so that the shorter-lived {sup 238}Pu isotope can be measured successfully. {sup 239}Pu, {sup 242}Pu and {sup 237}Np were measured by ICP-MS, while {sup 236}Pu and {sup 238}Pu were measured by alpha spectrometry.

  3. Investigations into the origins of polyatomic ions in inductively coupled plasma-mass spectrometry

    SciTech Connect (OSTI)

    McIntyre, Sally M.

    2010-05-16

    An inductively coupled plasma-mass spectrometer (ICP-MS) is an elemental analytical instrument capable of determining nearly all elements in the periodic table at limits of detection in the parts per quadrillion and with a linear analytical range over 8-10 orders of magnitude. Three concentric quartz tubes make up the plasma torch. Argon gas is spiraled through the outer tube and generates the plasma powered by a looped load coil operating at 27.1 or 40.6 MHz. The argon flow of the middle channel is used to keep the plasma above the innermost tube through which solid or aqueous sample is carried in a third argon stream. A sample is progressively desolvated, atomized and ionized. The torch is operated at atmospheric pressure. To reach the reduced pressures of mass spectrometers, ions are extracted through a series of two, approximately one millimeter wide, circular apertures set in water cooled metal cones. The space between the cones is evacuated to approximately one torr. The space behind the second cone is pumped down to, or near to, the pressure needed for the mass spectrometer (MS). The first cone, called the sampler, is placed directly in the plasma plume and its position is adjusted to the point where atomic ions are most abundant. The hot plasma gas expands through the sampler orifice and in this expansion is placed the second cone, called the skimmer. After the skimmer traditional MS designs are employed, i.e. quadrupoles, magnetic sectors, time-of-flight. ICP-MS is the leading trace element analysis technique. One of its weaknesses are polyatomic ions. This dissertation has added to the fundamental understanding of some of these polyatomic ions, their origins and behavior. Although mainly continuing the work of others, certain novel approaches have been introduced here. Chapter 2 includes the first reported efforts to include high temperature corrections to the partition functions of the polyatomic ions in ICP-MS. This and other objections to preceeding

  4. Studies of the mechanism of the cluster formation in a thermally sampling atmospheric pressure ionization mass spectrometer

    SciTech Connect (OSTI)

    Albrecht, Sascha Stroh, Fred; Klopotowski, Sebastian Derpmann, Valerie Klee, Sonja Brockmann, Klaus J. Benter, Thorsten

    2014-01-15

    In this study a thermally sampling atmospheric pressure ionization mass spectrometer is described and characterized. The ion transfer stage offers the capability to sample cluster ions at thermal equilibrium and during this transfer fundamental processes possibly affecting the cluster distribution are also readily identified. Additionally, the transfer stage combines optional collision-induced dissociation (CID) analysis of the cluster composition with thermal equilibrium sampling of clusters. The performance of the setup is demonstrated with regard to the proton-bound water cluster system. The benefit of the studied processes is that they can help to improve future transfer stages and to understand cluster ion reactions in ion mobility tubes and high-pressure ion sources. In addition, the instrument allows for the identification of fragmentation and protonation reactions caused by CID.

  5. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; Turteltaub, Kenneth W.; Newman, Lee S.

    2014-06-16

    We report that exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstratemore » that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, we determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) then HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.« less

  6. High resolution mass spectrometry method and system for analysis of whole proteins and other large molecules

    DOE Patents [OSTI]

    Reilly, Peter T. A. [Knoxville, TN; Harris, William A. [Naperville, IL

    2010-03-02

    A matrix assisted laser desorption/ionization (MALDI) method and related system for analyzing high molecular weight analytes includes the steps of providing at least one matrix-containing particle inside an ion trap, wherein at least one high molecular weight analyte molecule is provided within the matrix-containing particle, and MALDI on the high molecular weight particle while within the ion trap. A laser power used for ionization is sufficient to completely vaporize the particle and form at least one high molecular weight analyte ion, but is low enough to avoid fragmenting the high molecular weight analyte ion. The high molecular weight analyte ion is extracted out from the ion trap, and is then analyzed using a detector. The detector is preferably a pyrolyzing and ionizing detector.

  7. Efficient mass-selective three-photon ionization of zirconium atoms

    DOE Patents [OSTI]

    Page, R.H.

    1994-12-27

    In an AVLIS process, [sup 91]Zr is selectively removed from natural zirconium by a three-step photoionization wherein Zr atoms are irradiated by a laser beam having a wavelength [lambda][sub 1], selectively raising [sup 91]Zr atoms to an odd-parity E[sub 1] energy level in the range of 16000--19000 cm[sup [minus]1], are irradiated by a laser beam having a wavelength [lambda][sub 2] to raise the atoms from an E[sub l] level to an even-parity E[sub 2] energy level in the range of 35000--37000 cm[sup [minus]1] and are irradiated by a laser beam having a wavelength [lambda][sub 3] to cause a resonant transition of atoms from an E[sub 2] level to an autoionizing level above 53506 cm[sup [minus]1][lambda][sub 3] wavelengths of 5607, 6511 or 5756 [angstrom] will excite a zirconium atom from an E[sub 2] energy state of 36344 cm[sup [minus]1] to an autoionizing level; a [lambda][sub 3] wavelength of 5666 [angstrom] will cause an autoionizing transition from an E[sub 2] level of 36068 cm[sup [minus]1]; and a [lambda][sub 3] wavelength of 5662 [angstrom] will cause an ionizing resonance of an atom at an E[sub 2] level of 35904 cm[sup [minus]1]. 4 figures.

  8. Efficient mass-selective three-photon ionization of zirconium atoms

    DOE Patents [OSTI]

    Page, Ralph H.

    1994-01-01

    In an AVLIS process, .sup.91 Zr is selectively removed from natural zirconium by a three-step photoionization wherein Zr atoms are irradiated by a laser beam having a wavelength .lambda..sub.1, selectively raising .sup.91 Zr atoms to an odd-parity E.sub.1 energy level in the range of 16000-19000 cm.sup.-1, are irradiated by a laser beam having a wavelength .lambda..sub.2 to raise the atoms from an E.sub.l level to an even-parity E.sub.2 energy level in the range of 35000-37000 cm.sup.-1 and are irradiated by a laser beam having a wavelength .lambda..sub.3 to cause a resonant transition of atoms from an E.sub.2 level to an autoionizing level above 53506 cm.sup.-1. .lambda..sub.3 wavelengths of 5607, 6511 or 5756 .ANG. will excite a zirconium atom from an E.sub.2 energy state of 36344 cm.sup.-1 to an autoionizing level; a .lambda..sub.3 wavelength of 5666 .ANG. will cause an autoionizing transition from an E.sub.2 level of 36068 cm.sup.-1 ; and a .lambda. .sub.3 wavelength of 5662 .ANG. will cause an ionizing resonance of an atom at an E.sub.2 level of 35904 cm.sup.-1.

  9. Metabolomics relative quantitation with mass spectrometry using chemical derivatization and isotope labeling

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    O'Maille, Grace; Go, Eden P.; Hoang, Linh; Want, Elizabeth J.; Smith, Colin; O'Maille, Paul; NordstrÖm, Anders; Morita, Hirotoshi; Qin, Chuan; Uritboonthai, Wilasinee; et al

    2008-01-01

    Comprehensive detection and quantitation of metabolites from a biological source constitute the major challenges of current metabolomics research. Two chemical derivatization methodologies, butylation and amination, were applied to human serum for ionization enhancement of a broad spectrum of metabolite classes, including steroids and amino acids. LC-ESI-MS analysis of the derivatized serum samples provided a significant signal elevation across the total ion chromatogram to over a 100-fold increase in ionization efficiency. It was also demonstrated that derivatization combined with isotopically labeled reagents facilitated the relative quantitation of derivatized metabolites from individual as well as pooled samples.

  10. Laser ablation ICP-mass spectrometry determination of Th{sup 230} in soils at the Gunnison, Colorado UMTRA site

    SciTech Connect (OSTI)

    Anderson, M.S.; Braymen, S.; McIntosh, R.

    1994-02-16

    This report describes an innovative technology, laser ablation-inductively couple plasma-mass spectrometry (LA-ICP-MS), operated in a mobile laboratory, to rapidly detect thorium 230 activity levels in soil samples. This technology was demonstrated on-site during November 1993 at the Gunnison, Colorado, UMTRA project site in support of their remediation effort. The LA-ICP-MS sampling and analysis technique was chosen because of the capability for rapid analysis, approximately three samples per hour, with minimal sample preparation.

  11. Recommendations for the generation, quantification, storage and handling of peptides used for mass spectrometry-based assays

    SciTech Connect (OSTI)

    Hoofnagle, Andrew N.; Whiteaker, Jeffrey R.; Carr, Steven A.; Kuhn, Eric; Liu, Tao; Massoni, Sam A.; Thomas, Stefani N.; Townsend, Reid; Zimmerman, Lisa J.; Boja, Emily; Chen, Jing; Crimmins, Daniel L.; Davies, Sherri; Gao, Yuqian; Hiltke, Tara R.; Ketchum, Karen; Kinsinger, Christopher; Mesri, Mehdi; Meyer, Matthew R.; Qian, Weijun; Schoenherr, Regine M.; Scott, Mitchell; Shi, Tujin; Whiteley, Gordon; Wrobel, John; Wu, Chaochao; Ackermann, Bradley L.; Aebersold, Ruedi; Barnidge, David R.; Bunk, David M.; Clarke, Nigel; Fishman, Jordan B.; Grant, Russ P.; Kusebauch, Ulrike; Kushnir, Mark M.; Lowenthal, Mark S.; Moritz, Robert; Neubert, Hendrik; Patterson, Scott D.; Rockwood, Alan L.; Rogers, John; Singh, Ravinder J.; Van Eyk, Jennifer; Wong, Steven H.; Zhang, Shucha; Chan, Daniel W.; Chen, Xian; Ellis, Matthew J.; Liebler, Daniel; Rodland, Karin D.; Rodriguez, Henry; Smith, Richard D.; Zhang, Zhen; Zhang, Hui; Paulovich, Amanda G.

    2015-12-30

    The Clinical Proteomic Tumor Analysis Consortium (1) (CPTAC) of the National Cancer Institute (NCI) is a comprehensive and coordinated effort to accelerate the understanding of the molecular basis of cancer through the application of robust technologies and workflows for the quantitative measurements of proteins. The Assay Development Working Group of the CPTAC Program aims to foster broad uptake of targeted mass spectrometry-based assays employing isotopically labeled peptides for confident assignment and quantification, including multiple reaction monitoring (MRM; also referred to as Selected Reaction Monitoring), parallel reaction monitoring (PRM), and other targeted methods.

  12. Enhancement of concentration range of chromatographically detectable components with array detector mass spectrometry

    DOE Patents [OSTI]

    Enke, Christie

    2013-02-19

    Methods and instruments for high dynamic range analysis of sample components are described. A sample is subjected to time-dependent separation, ionized, and the ions dispersed with a constant integration time across an array of detectors according to the ions m/z values. Each of the detectors in the array has a dynamically adjustable gain or a logarithmic response function, producing an instrument capable of detecting a ratio of responses or 4 or more orders of magnitude.

  13. Validating mass spectrometry measurements of nuclear materials via a non-contact volume analysis method of ion sputter craters

    SciTech Connect (OSTI)

    Willingham, David G.; Naes, Benjamin E.; Fahey, Albert J.

    2015-01-01

    A combination of secondary ion mass spectrometry, optical profilometry and a statistically-driven algorithm was used to develop a non-contact volume analysis method to validate the useful yields of nuclear materials. The volume analysis methodology was applied to ion sputter craters created in silicon and uranium substrates sputtered by 18.5 keV O- and 6.0 keV Ar+ ions. Sputter yield measurements were determined from the volume calculations and were shown to be comparable to Monte Carlo calculations and previously reported experimental observations. Additionally, the volume calculations were used to determine the useful yields of Si+, SiO+ and SiO2+ ions from the silicon substrate and U+, UO+ and UO2+ ions from the uranium substrate under 18.5 keV O- and 6.0 keV Ar+ ion bombardment. This work represents the first steps toward validating the interlaboratory and cross-platform performance of mass spectrometry for the analysis of nuclear materials.

  14. Characterization of direct current He-N{sub 2} mixture plasma using optical emission spectroscopy and mass spectrometry

    SciTech Connect (OSTI)

    Flores, O.; Castillo, F.; Martinez, H.; Villa, M.; Reyes, P. G.; Villalobos, S.; Facultad de Ingeniera, Universidad Nacional Autnoma de Mxico, Mxico D.F.

    2014-05-15

    This study analyses the glow discharge of He and N{sub 2} mixture at the pressure of 2.0?Torr, power of 10?W, and flow rate of 16.5?l/min, by using optical emission spectroscopy and mass spectrometry. The emission bands were measured in the wavelength range of 2001100?nm. The principal species observed were N{sub 2}{sup +} (B{sup 2}?{sup +}{sub u}?X{sup 2}?{sup +}{sub g}), N{sub 2} (C{sup 3}?{sub u}?B{sup 3}?{sub g}), and He, which are in good agreement with the results of mass spectrometry. Besides, the electron temperature and ion density were determined by using a double Langmuir probe. Results indicate that the electron temperature is in the range of 1.552.93?eV, and the electron concentration is of the order of 10{sup 10}?cm{sup ?3}. The experimental results of electron temperature and ion density for pure N{sub 2} and pure He are in good agreement with the values reported in the literature.

  15. Biological Mass Spectrometry and Shotgun Proteomics of Microbial Systems: Methods for studying microbial physiology from isolates to environmental communities

    SciTech Connect (OSTI)

    Dill, Brian; Young, Jacque C; Carey, Patricia A; Verberkmoes, Nathan C

    2010-01-01

    Microbial ecology is currently experiencing a renaissance spurred by the rapid development of molecular techniques and omics technologies in particular. As never before, these tools have allowed researchers in the field to produce a massive amount of information through in situ measurements and analysis of natural microbial communities, both vital approaches to the goal of unraveling the interactions of microbes with their environment and with one another. While genomics can provide information regarding the genetic potential of microbes, proteomics characterizes the primary end-stage product, proteins, thus conveying functional information concerning microbial activity. Advances in mass spectrometry instrumentation and methodologies, along with bioinformatic approaches, have brought this analytic chemistry technique to relevance in the biological realm due to its powerful applications in proteomics. Mass spectrometry-enabled proteomics, including bottom-up and top-down approaches, is capable of supplying a wealth of biologically-relevant information, from simple protein cataloging of the proteome of a microbial community to identifying post-translational modifications of individual proteins.

  16. Calibration of laser ablation inductively coupled plasma mass spectrometry using dried solution aerosols for the quantitative analysis of solid samples

    SciTech Connect (OSTI)

    Leach, J.

    1999-02-12

    Inductively coupled plasma mass spectrometry (ICP-MS) has become the method of choice for elemental and isotopic analysis. Several factors contribute to its success. Modern instruments are capable of routine analysis at part per trillion levels with relative detection limits in part per quadrillion levels. Sensitivities in these instruments can be as high as 200 million counts per second per part per million with linear dynamic ranges up to eight orders of magnitude. With standards for only a few elements, rapid semiquantitative analysis of over 70 elements in an individual sample can be performed. Less than 20 years after its inception ICP-MS has shown to be applicable to several areas of science. These include geochemistry, the nuclear industry, environmental chemistry, clinical chemistry, the semiconductor industry, and forensic chemistry. In this introduction, the general attributes of ICP-MS will be discussed in terms of instrumentation and sample introduction. The advantages and disadvantages of current systems are presented. A detailed description of one method of sample introduction, laser ablation, is given. The paper also gives conclusions and suggestions for future work. Chapter 2, Quantitative analysis of solids by laser ablation inductively coupled plasma mass spectrometry using dried solution aerosols for calibration, has been removed for separate processing.

  17. Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry

    SciTech Connect (OSTI)

    Schaefer, R. T.; Mojarradi, M.; MacAskill, J. A.; Chutjian, A.; Darrach, M. R.; Madzunkov, S. M.; Shortt, B. J.

    2008-09-15

    Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware.

  18. Atmospheric solids analysis probe mass spectrometry for the rapid identification of pollens and semi-quantification of flavonoid fingerprints

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xiao, Xiaoyin; Miller, Lance L.; Parchert, Kylea J.; Hayes, Dulce; Hochrein, James M.

    2016-06-08

    From allergies to plant reproduction, pollens have important impacts on the health of human and plant populations, yet identification of pollen grains remains difficult and time-consuming. Low-volatility flavonoids generated from pollens cannot be easily characterized and quantified with current analytical techniques. Here we demonstrate the novel use of atmospheric solids analysis probe mass spectrometry (ASAP-MS) for the characterization of flavonoids in pollens. Flavonoid patterns were generated for pollens collected from different plant types (trees and bushes) in addition to bee pollens from distinct geographic regions. Standard flavonoids (kaempferol and rhamnazin) and those produced from pollens were compared and assessed withmore » ASAP-MS using low-energy collision MS/MS. Results for a semi-quantitative method for assessing the amount of a flavonoid in pollens are also presented.« less

  19. THE APPLICATION OF SINGLE PARTICLE AEROSOL MASS SPECTROMETRY FOR THE DETECTION AND IDENTIFICATION OF HIGH EXPLOSIVES AND CHEMICAL WARFARE AGENTS

    SciTech Connect (OSTI)

    Martin, A

    2006-10-23

    Single Particle Aerosol Mass Spectrometry (SPAMS) was evaluated as a real-time detection technique for single particles of high explosives. Dual-polarity time-of-flight mass spectra were obtained for samples of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN); peaks indicative of each compound were identified. Composite explosives, Comp B, Semtex 1A, and Semtex 1H were also analyzed, and peaks due to the explosive components of each sample were present in each spectrum. Mass spectral variability with laser fluence is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle ({approx}1 pg) without the need for consumables is demonstrated. SPAMS was also applied to the detection of Chemical Warfare Agent (CWA) simulants in the liquid and vapor phases. Liquid simulants for sarin, cyclosarin, tabun, and VX were analyzed; peaks indicative of each simulant were identified. Vapor phase CWA simulants were adsorbed onto alumina, silica, Zeolite, activated carbon, and metal powders which were directly analyzed using SPAMS. The use of metal powders as adsorbent materials was especially useful in the analysis of triethyl phosphate (TEP), a VX stimulant, which was undetectable using SPAMS in the liquid phase. The capability of SPAMS to detect high explosives and CWA simulants using one set of operational conditions is established.

  20. Interface for the rapid analysis of liquid samples by accelerator mass spectrometry

    DOE Patents [OSTI]

    Turteltaub, Kenneth; Ognibene, Ted; Thomas, Avi; Daley, Paul F; Salazar Quintero, Gary A; Bench, Graham

    2014-02-04

    An interface for the analysis of liquid sample having carbon content by an accelerator mass spectrometer including a wire, defects on the wire, a system for moving the wire, a droplet maker for producing droplets of the liquid sample and placing the droplets of the liquid sample on the wire in the defects, a system that converts the carbon content of the droplets of the liquid sample to carbon dioxide gas in a helium stream, and a gas-accepting ion source connected to the accelerator mass spectrometer that receives the carbon dioxide gas of the sample in a helium stream and introduces the carbon dioxide gas of the sample into the accelerator mass spectrometer.

  1. Aerosol Mass Spectrometry via Laser-Induced Incandescence Particle Vaporization Final Report

    SciTech Connect (OSTI)

    Timothy B. Onasch

    2011-10-20

    We have successfully developed and commercialized a soot particle aerosol mass spectrometer (SP-AMS) instrument to measure mass, size, and chemical information of soot particles in ambient environments. The SP-AMS instrument has been calibrated and extensively tested in the laboratory and during initial field studies. The first instrument paper describing the SP-AMS has been submitted for publication in a peer reviewed journal and there are several related papers covering initial field studies and laboratory studies that are in preparation. We have currently sold 5 SP-AMS instruments (either as complete systems or as SP modules to existing AMS instrument operators).

  2. Direct Sampling and Analysis from Solid Phase Extraction Cards using an Automated Liquid Extraction Surface Analysis Nanoelectrospray Mass Spectrometry System

    SciTech Connect (OSTI)

    Walworth, Matthew J; ElNaggar, Mariam S; Stankovich, Joseph J; WitkowskiII, Charles E.; Norris, Jeremy L; Van Berkel, Gary J

    2011-01-01

    Direct liquid extraction based surface sampling, a technique previously demonstrated with continuous flow and autonomous pipette liquid microjunction surface sampling probes, has recently been implemented as the Liquid Extraction Surface Analysis (LESA) mode on the commercially available Advion NanoMate chip-based infusion nanoelectrospray ionization system. In the present paper, the LESA mode was applied to the analysis of 96-well format custom solid phase extraction (SPE) cards, with each well consisting of either a 1 or 2 mm diameter monolithic hydrophobic stationary phase. These substrate wells were conditioned, loaded with either single or multi-component aqueous mixtures, and read out using the LESA mode of a TriVersa NanoMate or a Nanomate 100 coupled to an ABI/Sciex 4000QTRAPTM hybrid triple quadrupole/linear ion trap mass spectrometer and a Thermo LTQ XL linear ion trap mass spectrometer. Extraction conditions, including extraction/nanoESI solvent composition, volume, and dwell times, were optimized in the analysis of targeted compounds. Limit of detection and quantitation as well as analysis reproducibility figures of merit were measured. Calibration data was obtained for propranolol using a deuterated internal standard which demonstrated linearity and reproducibility. A 10x increase in signal and cleanup of micromolar Angiotensin II from a concentrated salt solution was demonstrated. Additionally, a multicomponent herbicide mixture at ppb concentration levels was analyzed using MS3 spectra for compound identification in the presence of isobaric interferences.

  3. Mass spectrometry-based methods for detection and differentiation of botulinum neurotoxins

    DOE Patents [OSTI]

    Schmidt, Jurgen G.; Boyer, Anne E.; Kalb, Suzanne R.; Moura, Hercules; Barr, John R.; Woolfitt, Adrian R.

    2009-11-03

    The present invention is directed to a method for detecting the presence of clostridial neurotoxins in a sample by mixing a sample with a peptide that can serve as a substrate for proteolytic activity of a clostridial neurotoxin; and measuring for proteolytic activity of a clostridial neurotoxin by a mass spectroscopy technique. In one embodiment, the peptide can have an affinity tag attached at two or more sites.

  4. Nano-Scale Secondary Ion Mass Spectrometry - A new analytical tool in biogeochemistry and soil ecology

    SciTech Connect (OSTI)

    Herrmann, A M; Ritz, K; Nunan, N; Clode, P L; Pett-Ridge, J; Kilburn, M R; Murphy, D V; O'Donnell, A G; Stockdale, E A

    2006-10-18

    Soils are structurally heterogeneous across a wide range of spatio-temporal scales. Consequently, external environmental conditions do not have a uniform effect throughout the soil, resulting in a large diversity of micro-habitats. It has been suggested that soil function can be studied without explicit consideration of such fine detail, but recent research has indicated that the micro-scale distribution of organisms may be of importance for a mechanistic understanding of many soil functions. Due to a lack of techniques with adequate sensitivity for data collection at appropriate scales, the question 'How important are various soil processes acting at different scales for ecological function?' is challenging to answer. The nano-scale secondary ion mass spectrometer (NanoSIMS) represents the latest generation of ion microprobes which link high-resolution microscopy with isotopic analysis. The main advantage of NanoSIMS over other secondary ion mass spectrometers is the ability to operate at high mass resolution, whilst maintaining both excellent signal transmission and spatial resolution ({approx}50 nm). NanoSIMS has been used previously in studies focusing on presolar materials from meteorites, in material science, biology, geology and mineralogy. Recently, the potential of NanoSIMS as a new tool in the study of biophysical interfaces in soils has been demonstrated. This paper describes the principles of NanoSIMS and discusses the potential of this tool to contribute to the field of biogeochemistry and soil ecology. Practical considerations (sample size and preparation, simultaneous collection of isotopes, mass resolution, isobaric interference and quantification of the isotopes of interest) are discussed. Adequate sample preparation avoiding biases in the interpretation of NanoSIMS data due to artifacts and identification of regions-of interest are of most concerns in using NanoSIMS as a new tool in biogeochemistry and soil ecology. Finally, we review the areas of

  5. Reduction of plyatomic ion interferences in indictively coupled plasma mass spectrometry with cryogenic desolvation

    SciTech Connect (OSTI)

    Alves, L.C.

    1993-09-01

    A desolvation scheme for introducing aqueous and organic samples into an argon inductively coupled plasma is described; the aerosol generated by nebulizer is heated (+140 C) and cooled ({minus}80 C) repeatedly, and the dried aerosol is then injected into the mass spectrometer. Polyatomic ions are greatly suppressed. This scheme was validated with analysis of seawater and urine reference samples. Finally, the removal of organic solvents by cryogenic desolvation was studied.

  6. Comparative Evaluation of Preprocessing Freeware on Chromatography/Mass Spectrometry Data for Signature Discovery

    SciTech Connect (OSTI)

    Coble, Jamie B.; Fraga, Carlos G.

    2014-07-07

    Preprocessing software is crucial for the discovery of chemical signatures in metabolomics, chemical forensics, and other signature-focused disciplines that involve analyzing large data sets from chemical instruments. Here, four freely available and published preprocessing tools known as metAlign, MZmine, SpectConnect, and XCMS were evaluated for impurity profiling using nominal mass GC/MS data and accurate mass LC/MS data. Both data sets were previously collected from the analysis of replicate samples from multiple stocks of a nerve-agent precursor. Each of the four tools had their parameters set for the untargeted detection of chromatographic peaks from impurities present in the stocks. The peak table generated by each preprocessing tool was analyzed to determine the number of impurity components detected in all replicate samples per stock. A cumulative set of impurity components was then generated using all available peak tables and used as a reference to calculate the percent of component detections for each tool, in which 100% indicated the detection of every component. For the nominal mass GC/MS data, metAlign performed the best followed by MZmine, SpectConnect, and XCMS with detection percentages of 83, 60, 47, and 42%, respectively. For the accurate mass LC/MS data, the order was metAlign, XCMS, and MZmine with detection percentages of 80, 45, and 35%, respectively. SpectConnect did not function for the accurate mass LC/MS data. Larger detection percentages were obtained by combining the top performer with at least one of the other tools such as 96% by combining metAlign with MZmine for the GC/MS data and 93% by combining metAlign with XCMS for the LC/MS data. In terms of quantitative performance, the reported peak intensities had average absolute biases of 41, 4.4, 1.3 and 1.3% for SpectConnect, metAlign, XCMS, and MZmine, respectively, for the GC/MS data. For the LC/MS data, the average absolute biases were 22, 4.5, and 3.1% for metAlign, MZmine, and XCMS

  7. Characterization of Two Different Clay Materials by Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dilatometry (DIL) and Mass Spectrometry (MS) - 12215

    SciTech Connect (OSTI)

    Post, Ekkehard; Henderson, Jack B.

    2012-07-01

    An illitic clay containing higher amounts of organic materials was investigated by dilatometry, thermogravimetry and differential scanning calorimetric. The evolved gases were studied during simultaneous TG-DSC (STA) and dilatometer measurements with simultaneous mass spectrometry in inert gas and oxidizing atmosphere. The dilatometer results were compared with the STA-MS results which confirmed and explained the reactions found during heating of the clay, like dehydration, dehydroxylation, shrinkage, sintering, quartz phase transition, combustion or pyrolysis of organics and the solid state reactions forming meta-kaolinite and mullite. The high amount of organic material effects in inert gas atmosphere most probably a reduction of the oxides which leads to a higher mass loss than in oxidizing atmosphere. Due to this reduction an additional CO{sub 2} emission at around 1000 deg. C was detected which did not occur in oxidizing atmosphere. Furthermore TG-MS results of a clay containing alkali nitrates show that during heating, in addition to water and CO{sub 2}, NO and NO{sub 2} are also evolved, leading to additional mass loss steps. These types of clays showed water loss starting around 100 deg. C or even earlier. This relative small mass loss affects only less shrinkage during the expansion of the sample. The dehydroxylation and the high crystalline quartz content result in considerable shrinkage and expansion of the clay. During the usual solid state reaction where the clay structure collapses, the remaining material finally shrinks down to a so-called clinker. With the help of MS the TG steps can be better interpreted as the evolved gases are identified. With the help of the MS it is possible to distinguish between CO{sub 2} and water (carbonate decomposition, oxidation of organics or dehydration/dehydroxylation). The MS also clearly shows that mass number 44 is found during the TG step of the illitic clay at about 900 deg. C in inert gas, which was interpreted

  8. Characterization of Plasma Membrane Proteins from Ovarian Cancer Cells Using Mass Spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Springer, David L.; Auberry, Deanna L.; Ahram, Mamoun; Adkins, Joshua N.; Feldhaus, Jane M.; Wahl, Jon H.; Wunschel, David S.; Rodland, Karin D.

    2004-01-01

    To determine how the repertoire of plasma membrane proteins change with disease state, specifically related to cancer, several methods for preparation of plasma membrane proteins were evaluated. Cultured cells derived from stage IV ovarian tumors were grown to 90% confluence and harvested in buffer containing CHAPS detergent. This preparation was centrifuged at low speed to remove insoluble cellular debris resulting in a crude homogenate. Glycosylated proteins in the crude homogenate were selectively enriched using lectin affinity chromatography. The crude homogenate and the lectin purified sample were prepared for mass spectrometric evaluation. The general procedure for protein identification began with trypsinmore » digestion of protein fractions followed by separation by reversed phase liquid chromatography that was coupled directly to a conventional tandem mass spectrometer (i.e. LCQ ion trap). Mass and fragmentation data for the peptides were searched against a human proteome data base using the informatics program SEQUEST. Using this procedure 398 proteins were identified with high confidence, including receptors, membrane-associated ligands, proteases, phosphatases, as well as structural and adhesion proteins. Results indicate that lectin chromatography provides a select subset of proteins and that the number and quality of the identifications improve as does the confidence of the protein identifications for this subset. These results represent the first step in development of methods to separate and successfully identify plasma membrane proteins from advanced ovarian cancer cells. Further characterization of plasma membrane proteins will contribute to our understanding of the mechanisms underlying progression of this deadly disease and may lead to new targeted interventions as well as new biomarkers for diagnosis.« less

  9. Characterization of Plasma Membrane Proteins from Ovarian Cancer Cells Using Mass Spectrometry

    SciTech Connect (OSTI)

    Springer, David L.; Auberry, Deanna L.; Ahram, Mamoun; Adkins, Joshua N.; Feldhaus, Jane M.; Wahl, Jon H.; Wunsch, David M.; Rodland, Karin D.

    2003-01-01

    To determine how the repertoire of plasma membrane proteins change with disease state, specifically related to cancer, several methods for preparation of plasma membrane proteins were evaluated. Cultured cells derived from stage IV ovarian tumors were grown to 90% confluence and harvested in buffer containing CHAPS detergent. This preparation was centrifuged at low speed to remove insoluble cellular debris resulting in a crude homogenate. Glycosylated proteins in the crude homogenate were selectively enriched using lectin affinity chromatography. The crude homogenate and the lectin purified sample were prepared for mass spectrometric evaluation. The general procedure for protein identification began with trypsin digestion of protein fractions followed by separation by reversed phase liquid chromatography that was coupled directly to a conventional tandem mass spectrometer (i.e. LCQ ion trap). Mass and fragmentation data for the peptides were searched against a human proteome data base using the informatics program SEQUEST. Using this procedure 398 proteins were identified with high confidence, including receptors, membrane-associated ligands, proteases, phosphatases, as well as structural and adhesion proteins. Results indicate that lectin chromatography provides a select subset of proteins and that the number and quality of the identifications improve as does the confidence of the protein identifications for this subset. These results represent the first step in development of methods to separate and successfully identify plasma membrane proteins from advanced ovarian cancer cells. Further characterization of plasma membrane proteins will contribute to our understanding of the mechanisms underlying progression of this deadly disease and may lead to new targeted interventions as well as new biomarkers for diagnosis.

  10. Alleviation of interferences and reduction of sample memory in inductively coupled plasma mass spectrometry

    SciTech Connect (OSTI)

    Smith, F.G.

    1991-06-27

    A simple variation sample preparation and introduction allows the measurement of chlorine isotope ratios by inductively coupled plasma mass spectroscopy (ICP-MS). Dissolution of the sample in D{sub 2}O rather than H{sub 2}O attenuates the major polyatomic ion {sup 36}ArH{sup +} and frees m/z = 37 for determination of {sup 37}Cl{sup +}. The isotope ratio {sup 35}Cl/{sup 37}Cl in a 50 mg L{sup {minus}1} solution of Cl as LiCl is determined with a relative standard deviation (RDS) of 0.21%. A method for the determination of boron is a variety of biological samples is described. Sample material is fused with Na{sub 2}CO{sub 3} and boron is separated from matrix components by using Amberlite IRA-743 boron selective ion-exchange resin. Boron is eluted with 1% HNO{sub 3} and samples are introduced to an ICP-mass spectrometer with a direct injection nebulizer (DIN). Xenon is added at 10 or 37 mL min{sup {minus}1} to the aerosol gas flow of an argon ICP-mass spectrometer. Addition of Xe substantially reduces polyatomic ions such as N{sub 2}{sup +}, HN{sub 2}{sup +}, NO{sup +}, ArH{sup +}, ClO{sup +}, ArC{sup +}, ClOH{sup +}, ArN{sup +}, and ArO{sup +} and facilitates the measurement of Si, K, V, Cr, and Fe. Isotope ratios are determined with RSDs from 0.6% to 1.6%. 210 refs., 14 figs., 19 tabs.

  11. The slow ionized wind and rotating disklike system that are associated with the high-mass young stellar object G345.4938+01.4677

    SciTech Connect (OSTI)

    Guzmn, Andrs E.; Garay, Guido; Bronfman, Leonardo; Mardones, Diego; Rodrguez, Luis F.; Moran, James; Brooks, Kate J.; Nyman, Lars-ke; Sanhueza, Patricio

    2014-12-01

    We report the detection, made using ALMA, of the 92 GHz continuum and hydrogen recombination lines (HRLs) H40?, H42?, and H50? emission toward the ionized wind associated with the high-mass young stellar object G345.4938+01.4677. This is the luminous central dominating source located in the massive and dense molecular clump associated with IRAS 165623959. The HRLs exhibit Voigt profiles, which is a strong signature of Stark broadening. We successfully reproduce the observed continuum and HRLs simultaneously using a simple model of a slow ionized wind in local thermodynamic equilibrium, with no need for a high-velocity component. The Lorentzian line wings imply electron densities of 5 10{sup 7} cm{sup 3} on average. In addition, we detect SO and SO{sub 2} emission arising from a compact (?3000 AU) molecular core associated with the central young star. The molecular core exhibits a velocity gradient that is perpendicular to the jet-axis, which we interpret as evidence of rotation. The set of observations toward G345.4938+01.4677 are consistent with it being a young high-mass star associated with a slow photo-ionized wind.

  12. Extending the Capabilities of Single Particle Mass Spectrometry: II. Measurements of Aerosol Particle Density without DMA

    SciTech Connect (OSTI)

    Vaden, Timothy D.; Imre, D.; Beranek, Josef; Zelenyuk, Alla

    2011-01-04

    Particle density is an important and useful property that is difficult to measure because it usually 5 requires separate instruments to measure two particle attributes. As density measurements are 6 often performed on size-classified particles, they are hampered by low particle numbers, and 7 hence poor temporal resolution. We present here a new method for measuring particle densities 8 using our single particle mass spectrometer, SPLAT. This method takes advantage of the fact 9 that the detection efficiency in our single particle mass spectrometer drops off very rapidly as the 10 particle size decreases below ~125 nm creating a distinct sharp feature on the small particle side 11 of the vacuum aerodynamic size distribution. Thus, the two quantities needed to determine 12 particle density, the particle diameter and vacuum aerodynamic diameter, are known. We first 13 test this method on particles of known composition and find that the densities it yields are 14 sufficiently accurate. We then apply the method to obtain the densities of particles that were 15 characterized during an airborne field campaign. In addition, we show that the distinctive 16 features of the vacuum aerodynamic size distribution can be used to characterize the instrument 17 detection efficiency as a function of particle size. In general, the method presented here reduces 18 complexity and yields information with high temporal resolution while the instrument is 19 collecting routine data on particle size and composition.

  13. Laser-ablation sampling for inductively coupled plasma distance-of-flight mass spectrometry

    SciTech Connect (OSTI)

    Gundlach-Graham, Alexander W.; Dennis, Elise; Ray, Steven J.; Enke, Christie G.; Barinaga, Charles J.; Koppenaal, David W.; Hieftje, Gary M.

    2015-01-01

    An inductively coupled plasma distance-of-flight mass spectrometer (ICP-DOFMS) has been coupled with laser-ablation (LA) sample introduction for the elemental analysis of solids. ICP-DOFMS is well suited for the analysis of laser-generated aerosols because it offers both high-speed mass analysis and simultaneous multi-elemental detection. Here, we evaluate the analytical performance of the LA-ICP-DOFMS instrument, equipped with a microchannel plate-based imaging detector, for the measurement of steady-state LA signals, as well as transient signals produced from single LA events. Steady-state detection limits are 1 mg g1, and absolute single-pulse LA detection limits are 200 fg for uranium; the system is shown capable of performing time-resolved single-pulse LA analysis. By leveraging the benefits of simultaneous multi-elemental detection, we also attain a good shot-to-shot reproducibility of 6% relative standard deviation (RSD) and isotope-ratio precision of 0.3% RSD with a 10 s integration time.

  14. Multiphoton ionization of large water clusters

    SciTech Connect (OSTI)

    Apicella, B.; Li, X.; Passaro, M.; Spinelli, N.; Wang, X.

    2014-05-28

    Water clusters are multimers of water molecules held together by hydrogen bonds. In the present work, multiphoton ionization in the UV range coupled with time of flight mass spectrometry has been applied to water clusters with up to 160 molecules in order to obtain information on the electronic states of clusters of different sizes up to dimensions that can approximate the bulk phase. The dependence of ion intensities of water clusters and their metastable fragments produced by laser ionization at 355 nm on laser power density indicates a (3+1)-photon resonance-enhanced multiphoton ionization process. It also explains the large increase of ionization efficiency at 355 nm compared to that at 266 nm. Indeed, it was found, by applying both nanosecond and picosecond laser ionization with the two different UV wavelengths, that no water cluster sequences after n = 9 could be observed at 266 nm, whereas water clusters up to m/z 2000 Th in reflectron mode and m/z 3000 Th in linear mode were detected at 355 nm. The agreement between our findings on clusters of water, especially true in the range with n > 10, and reported data for liquid water supports the hypothesis that clusters above a critical dimension can approximate the liquid phase. It should thus be possible to study clusters just above 10 water molecules, for getting information on the bulk phase structure.

  15. The COS/UVES absorption survey of the Magellanic stream. III. Ionization, total mass, and inflow rate onto the Milky Way

    SciTech Connect (OSTI)

    Fox, Andrew J.; Thom, Christopher; Tumlinson, Jason; Ely, Justin; Kumari, Nimisha [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wakker, Bart P.; Hernandez, Audra K.; Haffner, L. Matthew [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Barger, Kathleen A.; Lehner, Nicolas; Howk, J. Christopher [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Richter, Philipp [Institut fr Physik und Astronomie, Universitt Potsdam, Haus 28, Karl-Liebknecht-Strasse 24/25, D-14476, Potsdam (Germany); Bland-Hawthorn, Joss [Institute of Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Charlton, Jane C. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Westmeier, Tobias [ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Misawa, Toru [School of General Education, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Rodriguez-Hidalgo, Paola, E-mail: afox@stsci.edu [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, ON M3J 1P3 (Canada)

    2014-06-01

    Dynamic interactions between the two Magellanic Clouds have flung large quantities of gas into the halo of the Milky Way. The result is a spectacular arrangement of gaseous structures, including the Magellanic Stream, the Magellanic Bridge, and the Leading Arm (collectively referred to as the Magellanic System). In this third paper of a series studying the Magellanic gas in absorption, we analyze the gas ionization level using a sample of 69 Hubble Space Telescope/Cosmic Origins Spectrograph sightlines that pass through or within 30 of the 21 cm emitting regions. We find that 81% (56/69) of the sightlines show UV absorption at Magellanic velocities, indicating that the total cross-section of the Magellanic System is ?11,000 deg{sup 2}, or around one-quarter of the entire sky. Using observations of the Si III/Si II ratio together with Cloudy photoionization modeling, we calculate the total gas mass (atomic plus ionized) of the Magellanic System to be ?2.0 10{sup 9} M {sub ?} (d/55 kpc){sup 2}, with the ionized gas contributing around three times as much mass as the atomic gas. This is larger than the current-day interstellar H I mass of both Magellanic Clouds combined, indicating that they have lost most of their initial gas mass. If the gas in the Magellanic System survives to reach the Galactic disk over its inflow time of ?0.5-1.0 Gyr, it will represent an average inflow rate of ?3.7-6.7 M {sub ?} yr{sup 1}, potentially raising the Galactic star formation rate. However, multiple signs of an evaporative interaction with the hot Galactic corona indicate that the Magellanic gas may not survive its journey to the disk fully intact and will instead add material to (and cool) the corona.

  16. Characterization of protein N-glycosylation by tandem mass spectrometry using complementary fragmentation techniques

    SciTech Connect (OSTI)

    Ford, Kristina L.; Zeng, Wei; Heazlewood, Joshua L.; Bacic, Antony

    2015-08-28

    The analysis of post-translational modifications (PTMs) by proteomics is regarded as a technically challenging undertaking. While in recent years approaches to examine and quantify protein phosphorylation have greatly improved, the analysis of many protein modifications, such as glycosylation, are still regarded as problematic. Limitations in the standard proteomics workflow, such as use of suboptimal peptide fragmentation methods, can significantly prevent the identification of glycopeptides. The current generation of tandem mass spectrometers has made available a variety of fragmentation options, many of which are becoming standard features on these instruments. Lastly, we have used three common fragmentation techniques, namely CID, HCD, and ETD, to analyze a glycopeptide and highlight how an integrated fragmentation approach can be used to identify the modified residue and characterize the N-glycan on a peptide.

  17. Separation of actinides using capillary extraction chromatography-inductively coupled plasma mass spectrometry

    SciTech Connect (OSTI)

    Peterson, Dominic S

    2008-01-01

    Trace levels of actinides have been separated on extraction chromatography columns. Detection of the actinides was achieved using an inductively coupled plasma mass spectrometer (ICP-MS), which was coupled with the extraction chromatography system. In this study we compare 30 cm long, 4.6 mm ID columns to capillary columns (750 {micro}m ID) with lengths from 30 cm up to 150 cm. The columns that were tested were packed with TRU resin. We were able to separate a mixture of five actinides ({sup 232}Th, {sup 238}U, {sup 237}Np, {sup 239}pU, {sup 241}Am). This work has application to rapid bioassay as well as for automated separations of actinide materials.

  18. Characterization of protein N-glycosylation by tandem mass spectrometry using complementary fragmentation techniques

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ford, Kristina L.; Zeng, Wei; Heazlewood, Joshua L.; Bacic, Antony

    2015-08-28

    The analysis of post-translational modifications (PTMs) by proteomics is regarded as a technically challenging undertaking. While in recent years approaches to examine and quantify protein phosphorylation have greatly improved, the analysis of many protein modifications, such as glycosylation, are still regarded as problematic. Limitations in the standard proteomics workflow, such as use of suboptimal peptide fragmentation methods, can significantly prevent the identification of glycopeptides. The current generation of tandem mass spectrometers has made available a variety of fragmentation options, many of which are becoming standard features on these instruments. Lastly, we have used three common fragmentation techniques, namely CID, HCD,more » and ETD, to analyze a glycopeptide and highlight how an integrated fragmentation approach can be used to identify the modified residue and characterize the N-glycan on a peptide.« less

  19. Online, absolute quantitation of propranolol from spatially distinct 20-μm and 40-μm dissections of brain, liver, and kidney thin tissue sections by laser microdissection – liquid vortex capture – mass spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kertesz, Vilmos; Vavrek, Marissa; Freddo, Carol; Van Berkel, Gary J.; Cahill, John F.; Weiskittel, Taylor M.

    2016-05-23

    Here, spatial resolved quantitation of chemical species in thin tissue sections by mass spectrometric methods has been constrained by the need for matrix-matched standards or other arduous calibration protocols and procedures to mitigate matrix effects (e.g., spatially varying ionization suppression). Reported here is the use of laser cut and drop sampling with a laser microdissection-liquid vortex capture electrospray ionization tandem mass spectrometry (LMD-LVC/ESI-MS/MS) system for online and absolute quantitation of propranolol in mouse brain, kidney, and liver thin tissue sections of mice administered with the drug at a 7.5 mg/kg dose, intravenously. In this procedure either 20 μm x 20more » μm or 40 μm x 40 μm tissue microdissections were cut and dropped into the flowing solvent of the capture probe. During transport to the ESI source drug related material was completely extracted from the tissue into the solvent, which contained a known concentration of propranolol-d7 as an internal standard. This allowed absolute quantitation to be achieved with an external calibration curve generated from standards containing the same fixed concentration of propranolold-d7 and varied concentrations of propranolol. Average propranolol concentrations determined with the laser cut and drop sampling method closely agreed with concentration values obtained from 2.3 mm diameter tissue punches from serial sections that were extracted and quantified by HPLC/ESI-MS/MS measurements. In addition, the relative abundance of hydroxypropranolol glucuronide metabolites were recorded and found to be consistent with previous findings.« less

  20. Development and Evaluation of an Externally Air-Cooled Low-Flow torch and the Attenuation of Space Charge and Matrix Effects in Inductively Coupled Plasma Mass Spectrometry

    SciTech Connect (OSTI)

    Praphairaksit, N.

    2000-09-12

    An externally air-cooled low-flow torch has been constructed and successfully demonstrated for applications in inductively coupled plasma mass spectrometry (ICP-MS). The torch is cooled by pressurized air flowing at {approximately}70 L/min through a quartz air jacket onto the exterior of the outer tube. The outer gas flow rate and operating RF forward power are reduced considerably. Although plasmas can be sustained at the operating power as low as 400 W with a 2 L/min of outer gas flow, somewhat higher power and outer gas flows are advisable. A stable and analytical useful plasma can be obtained at 850 W with an outer gas flow rate of {approximately}4 L/min. Under these conditions, the air-cooled plasma produces comparable sensitivities, doubly charged ion ratios, matrix effects and other analytical merits as those produced by a conventional torch while using significantly less argon and power requirements. Metal oxide ion ratios are slightly higher with the air-cooled plasma but can be mitigated by reducing the aerosol gas flow rate slightly with only minor sacrifice in analyte sensitivity. A methodology to alleviate the space charge and matrix effects in ICP-MS has been developed. A supplemental electron source adapted from a conventional electron impact ionizer is added to the base of the skimmer. Electrons supplied from this source downstream of the skimmer with suitable amount and energy can neutralize the positive ions in the beam extracted from the plasma and diminish the space charge repulsion between them. As a result, the overall ion transmission efficiency and consequent analyte ion sensitivities are significantly improved while other important analytical aspects, such as metal oxide ion ratio, doubly charged ion ratio and background ions remain relatively unchanged with the operation of this electron source. This technique not only improves the ion transmission efficiency but also minimizes the matrix effects drastically. The matrix-induced suppression

  1. Beyond single particle mass spectrometry: multidimensional characterisation of individual aerosol particles

    SciTech Connect (OSTI)

    Zelenyuk, Alla; Imre, D.

    2009-09-10

    The behavior of small aerosol particles depends on a number of their physical and chemical properties, many of which are strongly coupled. The size, internal composition, density, shape, morphology, hygroscopicity, index of refraction, activity as cloud condensation nuclei and ice nuclei, and other attributes of individual particles - all play a role in determining particle properties and their impacts. The traditional particle characterization approaches rely on separate parallel measurements that average over an ensemble of particles of different sizes and/or compositions and later attempt to draw correlations between them. As a result such studies overlook critical differences between particles and bulk and miss the fact that individual particles often exhibit major differences. Here we review the recently developed methods to simultaneously measure in-situ and in real time several of the attributes for individual particles using single particle mass spectrometer, SPLAT or its second generation SPLAT II. We also discuss novel approaches developed for classification, visualization and mining of large datasets produced by the multidimensional single particle characterization.

  2. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Horkley, J. J.; Carney, K. P.; Gantz, E. M.; Davies, J. E.; Lewis, R. R.; Crow, J. P.; Poole, C. A.; Grimes, T. S.; Giglio, J. J.

    2015-03-17

    Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure “spike” solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for “age” determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determinemore » 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.« less

  3. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    SciTech Connect (OSTI)

    Horkley, J. J.; Carney, K. P.; Gantz, E. M.; Davies, J. E.; Lewis, R. R.; Crow, J. P.; Poole, C. A.; Grimes, T. S.; Giglio, J. J.

    2015-03-17

    Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure “spike” solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for “age” determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determine 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.

  4. A Rational Approach for Discovering and Validating Cancer Markers in Very Small Samples Using Mass Spectrometry and ELISA Microarrays

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zangar, Richard C.; Varnum, Susan M.; Covington, Chandice Y.; Smith, Richard D.

    2004-01-01

    Identifying useful markers of cancer can be problematic due to limited amounts of sample. Some samples such as nipple aspirate fluid (NAF) or early-stage tumors are inherently small. Other samples such as serum are collected in larger volumes but archives of these samples are very valuable and only small amounts of each sample may be available for a single study. Also, given the diverse nature of cancer and the inherent variability in individual protein levels, it seems likely that the best approach to screen for cancer will be to determine the profile of a battery of proteins. As a result,more » a major challenge in identifying protein markers of disease is the ability to screen many proteins using very small amounts of sample. In this review, we outline some technological advances in proteomics that greatly advance this capability. Specifically, we propose a strategy for identifying markers of breast cancer in NAF that utilizes mass spectrometry (MS) to simultaneously screen hundreds or thousands of proteins in each sample. The best potential markers identified by the MS analysis can then be extensively characterized using an ELISA microarray assay. Because the microarray analysis is quantitative and large numbers of samples can be efficiently analyzed, this approach offers the ability to rapidly assess a battery of selected proteins in a manner that is directly relevant to traditional clinical assays.« less

  5. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    SciTech Connect (OSTI)

    J.J. Horkley; K.P E.M. Gantz; J.E. Davis; R.R. Lewis; J.P. Crow; C.A. Poole; T.S. Grimes; J.J. Giglio

    2015-03-01

    t Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure spike solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for age determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determine 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution,

  6. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    SciTech Connect (OSTI)

    Horkley, J. J.; Carney, K. P.; Gantz, E. M.; Davies, J. E.; Lewis, R. R.; Crow, J. P.; Poole, C. A.; Grimes, T. S.; Giglio, J. J.

    2015-03-17

    Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure spike solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for age determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determine 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.

  7. Determination of total chlorine and bromine in solid wastes by sintering and inductively coupled plasma-sector field mass spectrometry

    SciTech Connect (OSTI)

    Osterlund, Helene Rodushkin, Ilia; Ylinenjaervi, Karin; Baxter, Douglas C.

    2009-04-15

    A sample preparation method based on sintering, followed by analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) for the simultaneous determination of chloride and bromide in diverse and mixed solid wastes, has been evaluated. Samples and reference materials of known composition were mixed with a sintering agent containing Na{sub 2}CO{sub 3} and ZnO and placed in an oven at 560 deg. C for 1 h. After cooling, the residues were leached with water prior to a cation-exchange assisted clean-up. Alternatively, a simple microwave-assisted digestion using only nitric acid was applied for comparison. Thereafter the samples were prepared for quantitative analysis by ICP-SFMS. The sintering method was evaluated by analysis of certified reference materials (CRMs) and by comparison with US EPA Method 5050 and ion chromatography with good agreement. Median RSDs for the sintering method were determined to 10% for both chlorine and bromine, and median recovery to 96% and 97%, respectively. Limits of detection (LODs) were 200 mg/kg for chlorine and 20 mg/kg for bromine. It was concluded that the sintering method is suitable for chlorine and bromine determination in several matrices like sewage sludge, plastics, and edible waste, as well as for waste mixtures. The sintering method was also applied for determination of other elements present in anionic forms, such as sulfur, arsenic, selenium and iodine.

  8. Recommendations for mass spectrometry data quality metrics for open access data(corollary to the Amsterdam principles)

    SciTech Connect (OSTI)

    Kingsinger, Christopher R.; Apffel, James; Baker, Mark S.; Bian, Xiaopeng; Borchers, Christoph H.; Bradshaw, Ralph A.; Brusniak, Mi-Youn; Chan, Daniel W.; Deutsch, Eric W.; Domon, Bruno; Gorman, Jeff; Grimm, Rudolf; Hancock, William S.; Hermjakob, Henning; Horn, David; Hunter, Christie; Kolar, Patrik; Kraus, Hans-Joachim; Langen, Hanno; Linding, Rune; Moritz, Robert L.; Omenn, Gilbert S.; Orlando, Ron; Pandey, Akhilesh; Ping, Peipei; Rahbar, Amir; Rivers, Robert; Seymour, Sean L.; Simpson, Richard J.; Slotta, Douglas; Smith, Richard D.; Stein, Stephen E.; Tabb, David L.; Tagle, Danilo; Yates, John R.; Rodriguez, Henry

    2011-12-01

    Policies supporting the rapid and open sharing of proteomic data are being implemented by the leading journals in the field. The proteomics community is taking steps to ensure that data are made publicly accessible and are of high quality, a challenging task that requires the development and deployment of methods for measuring and documenting data quality metrics. On September 18, 2010, the U.S. National Cancer Institute (NCI) convened the 'International Workshop on Proteomic Data Quality Metrics' in Sydney, Australia, to identify and address issues facing the development and use of such methods for open access proteomics data. The stakeholders at the workshop enumerated the key principles underlying a framework for data quality assessment in mass spectrometry data that will meet the needs of the search community, journals, funding agencies, and data repositories. Attendees discussed and agreed upon two primary needs for the wide use of quality metrics: (i)an evolving list of comprehensive quality metrics and (ii)standards accompanied by software analytics. Attendees stressed the importance of increased education and training programs to promote reliable protocols in proteomics. This workshop report explores the historic precedents, key discussions, and necessary next steps to enhance the quality of open access data. By agreement, this article is published simultaneously in Proteomics, Proteomics Clinical Applications, Journal of Proteome Research, and Molecular and Cellular Proteomics, as a public service to the research community.The peer review process was a coordinated effort conducted by a panel of referees selected by the journals.

  9. Determination of total and isotopic uranium by inductively coupled plasma-mass spectrometry at the Fernald Environmental Management Project

    SciTech Connect (OSTI)

    Miller, F.L.; Bolin, R.N.; Feller, M.T.; Danahy, R.J.

    1995-04-01

    At the Fernald Environmental Management Project (FEMP) in southwestern Ohio, ICP-mass spectrometry (ICP-MS), with sample introduction by peristaltic pumping, is used to determine total and isotopic uranium (U-234, U-235, U-236 and U-238) in soil samples. These analyses are conducted in support of the environmental cleanup of the FEMP site. Various aspects of the sample preparation and instrumental analysis will be discussed. Initial sample preparation consists of oven drying to determine moisture content, and grinding and rolling to homogenize the sample. This is followed by a nitric/hydrofluoric acid digestion to bring the uranium in the sample into solution. Bismuth is added to the sample prior to digestion to monitor for losses. The total uranium (U-238) content of this solution and the U{sup 235}/U{sup 238} ratio are measured on the first pass through the ICP-MS. To determine the concentration of the less abundant U{sup 234} and U{sup 236} isotopes, the digestate is further concentrated by using Eichrom TRU-Spec extraction columns before the second pass through the ICP-MS. Quality controls for both the sample preparation and instrumental protocols will also be discussed. Finally, an explanation of the calculations used to report the data in either weight percent or activity units will be given.

  10. Detection of high molecular weight organic tracers in vegetation smoke samples by high-temperature gas chromatography-mass spectrometry

    SciTech Connect (OSTI)

    Elias, V.O.; Simoneit, B.R.T. ); Pereira, A.S.; Cardoso, J.N. ); Cabral, J.A. )

    1999-07-15

    High-temperature high-resolution gas chromatography (HTGC) is an established technique for the separation of complex mixtures of high molecular weight (HMW) compounds which do not elute when analyzed on conventional GC columns. The combination of this technique with mass spectrometry is not so common and application to aerosols is novel. The HTGC and HTGC-MS analyses of smoke samples taken by particle filtration from combustion of different species of plants provided the characterization of various classes of HMW compounds reported to occur for the first time in emissions from biomass burning. Among these components are a series of wax esters with up to 58 carbon numbers, aliphatic hydrocarbons, triglycerides, long chain methyl ketones, alkanols and a series of triterpenyl fatty acid esters which have been characterized as novel natural products. Long chain fatty acids with more than 32 carbon numbers are not present in the smoke samples analyzed. The HMW compounds in smoke samples from the burning of plants from Amazonia indicate the input of directly volatilized natural products in the original plants during their combustion. However, the major organic compounds extracted from smoke consist of a series of lower molecular weight polar components, which are not natural products but the result of the thermal breakdown of cellulose and lignin. In contrast, the HMW natural products may be suitable tracers for specific sources of vegetation combustion because they are emitted as particles without thermal alternation in the smoke and can thus be related directly to the original plant material.

  11. Radial arrays of nano-electrospray ionization emitters and methods of forming electrosprays

    DOE Patents [OSTI]

    Kelly, Ryan T [West Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

    2010-10-19

    Electrospray ionization emitter arrays, as well as methods for forming electrosprays, are described. The arrays are characterized by a radial configuration of three or more nano-electrospray ionization emitters without an extractor electrode. The methods are characterized by distributing fluid flow of the liquid sample among three or more nano-electrospray ionization emitters, forming an electrospray at outlets of the emitters without utilizing an extractor electrode, and directing the electrosprays into an entrance to a mass spectrometry device. Each of the nano-electrospray ionization emitters can have a discrete channel for fluid flow. The nano-electrospray ionization emitters are circularly arranged such that each is shielded substantially equally from an electrospray-inducing electric field.

  12. Enhancing Biological Analyses with Three Dimensional Field Asymmetric Ion Mobility, Low Field Drift Time Ion Mobility and Mass Spectrometry (FAIMS/IMS-MS) Separations

    SciTech Connect (OSTI)

    Zhang, Xing; Ibrahim, Yehia M.; Chen, Tsung-Chi; Kyle, Jennifer E.; Norheim, Randolph V.; Monroe, Matthew E.; Smith, Richard D.; Baker, Erin Shammel

    2015-06-30

    We report the first evaluation of a platform coupling a high speed field asymmetric ion mobility spectrometry microchip (FAIMS) with drift tube ion mobility and mass spectrometry (IMS-MS). The FAIMS/IMS-MS platform was used to analyze biological samples and simultaneously acquire multidimensional information of detected features from the measured FAIMS compensation fields and IMS drift times, while also obtaining accurate ion masses. These separations thereby increase the overall separation power, resulting increased information content, and provide more complete characterization of more complex samples. The separation conditions were optimized for sensitivity and resolving power by the selection of gas compositions and pressures in the FAIMS and IMS separation stages. The resulting performance provided three dimensional separations, benefitting both broad complex mixture studies and targeted analyses by e.g. improving isomeric separations and allowing detection of species obscured by chemical noise and other interfering peaks.

  13. Quantification of Semi-Volatile Oxygenated Components of Pyrolysis Bio-Oil by Gas Chromatography/Mass Spectrometry (GC/MS): Laboratory Analytical Procedure (LAP)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Quantification of Semi-Volatile Oxygenated Components of Pyrolysis Bio-Oil by Gas Chromatography/Mass Spectrometry (GC/MS) Laboratory Analytical Procedure (LAP) Issue Date: March 2, 2016 Earl Christensen and Jack Ferrell National Renewable Energy Laboratory Mariefel V. Olarte and Asanga B. Padmaperuma Pacific Northwest National Laboratory Technical Report NREL/TP-5100-65889 March 2016 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable

  14. SAMPLING AND MASS SPECTROMETRY APPROACHES FOR THE DETECTION OF DRUGS AND FOREIGN CONTAMINANTS IN BREATH FOR HOMELAND SECURITY APPLICATIONS

    SciTech Connect (OSTI)

    Martin, A N

    2009-01-27

    Homeland security relies heavily on analytical chemistry to identify suspicious materials and persons. Traditionally this role has focused on attribution, determining the type and origin of an explosive, for example. But as technology advances, analytical chemistry can and will play an important role in the prevention and preemption of terrorist attacks. More sensitive and selective detection techniques can allow suspicious materials and persons to be identified even before a final destructive product is made. The work presented herein focuses on the use of commercial and novel detection techniques for application to the prevention of terrorist activities. Although drugs are not commonly thought of when discussing terrorism, narcoterrorism has become a significant threat in the 21st century. The role of the drug trade in the funding of terrorist groups is prevalent; thus, reducing the trafficking of illegal drugs can play a role in the prevention of terrorism by cutting off much needed funding. To do so, sensitive, specific, and robust analytical equipment is needed to quickly identify a suspected drug sample no matter what matrix it is in. Single Particle Aerosol Mass Spectrometry (SPAMS) is a novel technique that has previously been applied to biological and chemical detection. The current work applies SPAMS to drug analysis, identifying the active ingredients in single component, multi-component, and multi-tablet drug samples in a relatively non-destructive manner. In order to do so, a sampling apparatus was created to allow particle generation from drug tablets with on-line introduction to the SPAMS instrument. Rules trees were developed to automate the identification of drug samples on a single particle basis. A novel analytical scheme was also developed to identify suspect individuals based on chemical signatures in human breath. Human breath was sampled using an RTube{trademark} and the trace volatile organic compounds (VOCs) were preconcentrated using solid

  15. Experimental Evaluation and Optimization of Structures for Lossless Ion Manipulations for Ion Mobility Spectrometry with Time-of-Flight Mass Spectrometry

    SciTech Connect (OSTI)

    Webb, Ian K.; Garimella, Venkata BS; Tolmachev, Aleksey V.; Chen, Tsung-Chi; Zhang, Xinyu; Norheim, Randolph V.; Prost, Spencer A.; Lamarche, Brian L.; Anderson, Gordon A.; Ibrahim, Yehia M.; Smith, Richard D.

    2014-09-05

    We report on the performance of Structures for Lossless Ion Manipulation (SLIM) devices as a means for transmitting ions and performing ion mobility separations (IMS). Ions were successfully transferred from an electrospray ionization (ESI) source to the TOF MS analyzer by means of a linear SLIM device and an alternative arrangement including a 90 turn. First, the linear geometry was optimized for radial confinement by tuning RF on the central rung electrodes and potentials on the DC-only guard electrodes. Selecting an appropriate DC guard bias (2-6 V) and RF amplitude (?160 Vp-p at 750 kHz) resulted in the greatest ion intensities. Close to ideal IMS resolving power was maintained over a range of applied voltages. Second, the 90 turn was optimized for radial confinement by tuning the RF on the rung electrodes and DC on the guard electrodes; however, both resolving power and ion transmission showed a dependence on these voltages and the best conditions for both were > 300 Vp-p RF (685 kHz) and 7-11 V guard DC bias. Both geometries provide IMS resolving powers at the theoretical limit (R~58), showing that the negative racetrack effect from turning around a corner can be successfully avoided, as well as the capability for essentially lossless ion transmission.

  16. Accelerator mass spectrometry facility at the University of Washington: current status, and an application to the /sup 14/C profile of a tree ring

    SciTech Connect (OSTI)

    Farwell, G.W.; Grootes, P.M.; Leach, D.D.; Schmidt, F.H.

    1984-01-01

    The University of Washington Model FN Tandem accelerator (1) is used for Accelerator Mass Spectrometry (AMS) of /sup 10/Be and /sup 14/C. This paper describes our basic system, our methods for rare-isotope normalization, final ion detection, and sample preparation, and the general problem of adapting an existing accelerator to meet the stringent stability requirements of precision AMS measurements while retaining human and technical compatibility with other users and uses of the accelerator. Recent preliminary data obtained on /sup 14/C in thin sequential sections of a single Sitka spruce tree ring (1963) are presented.

  17. Comparison of Internal Energy Distributions of Ions Created by Electrospray Ionization and Laser Ablation-Liquid Vortex Capture-Electrospray Ionization

    SciTech Connect (OSTI)

    Cahill, John F.; Kertesz, Vilmos; Ovchinnikova, Olga S.; Van Berkel, Gary J.

    2015-06-27

    Recently a number of techniques have combined laser ablation with liquid capture for mass spectrometry spot sampling and imaging applications. The newly developed non-contact liquid-vortex capture probe has been used to efficiently collect 355 nm UV laser ablated material in a continuous flow solvent stream in which the captured material dissolves and then undergoes electrospray ionization. This sampling and ionization approach has produced what appear to be classic electrospray ionization spectra; however, the softness of this sampling/ionization process versus simple electrospray ionization has not been definitely determined. A series of benzlypyridinium salts, known as thermometer ions, were used to compare internal energy distributions between electrospray ionization and the UV laser ablation liquid-vortex capture probe electrospray combination. Measured internal energy distributions were identical between the two techniques, even with differences in laser fluence (0.7-3.1 J cm-2) and when using UV-absorbing or non-UV-absorbing sample substrates. This data indicates ions formed directly by UV laser ablation, if any, are likely an extremely small constituent of the total ion signal observed. Instead, neutral molecules, clusters or particulates ejected from the surface during laser ablation, subsequently captured and dissolved in the flowing solvent stream then electrosprayed are the predominant source of ion signal observed. The electrospray ionization process used controls the softness of the technique.

  18. Comparison of Internal Energy Distributions of Ions Created by Electrospray Ionization and Laser Ablation-Liquid Vortex Capture-Electrospray Ionization

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cahill, John F.; Kertesz, Vilmos; Ovchinnikova, Olga S.; Van Berkel, Gary J.

    2015-06-27

    Recently a number of techniques have combined laser ablation with liquid capture for mass spectrometry spot sampling and imaging applications. The newly developed non-contact liquid-vortex capture probe has been used to efficiently collect 355 nm UV laser ablated material in a continuous flow solvent stream in which the captured material dissolves and then undergoes electrospray ionization. This sampling and ionization approach has produced what appear to be classic electrospray ionization spectra; however, the softness of this sampling/ionization process versus simple electrospray ionization has not been definitely determined. A series of benzlypyridinium salts, known as thermometer ions, were used to comparemore » internal energy distributions between electrospray ionization and the UV laser ablation liquid-vortex capture probe electrospray combination. Measured internal energy distributions were identical between the two techniques, even with differences in laser fluence (0.7-3.1 J cm-2) and when using UV-absorbing or non-UV-absorbing sample substrates. This data indicates ions formed directly by UV laser ablation, if any, are likely an extremely small constituent of the total ion signal observed. Instead, neutral molecules, clusters or particulates ejected from the surface during laser ablation, subsequently captured and dissolved in the flowing solvent stream then electrosprayed are the predominant source of ion signal observed. The electrospray ionization process used controls the softness of the technique.« less

  19. Ionization Thresholds of Small Carbon Clusters: Tunable VUVExperiments and Theory

    SciTech Connect (OSTI)

    Belau, Leonid; Wheeler, Steven E.; Ticknor, Brian W.; Ahmed,Musahid; Leone, Stephen R.; Allen, Wesley D.; Schaefer III, Henry F.; Duncan, Michael A.

    2007-07-31

    Small carbon clusters (Cn, n = 2-15) are produced in amolecular beam by pulsed laser vaporization and studied with vacuumultraviolet (VUV) photoionization mass spectrometry. The required VUVradiation in the 8-12 eV range is provided by the Advanced Light Source(ALS) at the Lawrence Berkeley National Laboratory. Mass spectra atvarious ionization energies reveal the qualitative relative abundances ofthe neutral carbon clusters produced. By far the most abundant species isC3. Using the tunability of the ALS, ionization threshold spectra arerecorded for the clusters up to 15 atoms in size. The ionizationthresholds are compared to those measured previously with charge-transferbracketing methods. To interpret the ionization thresholds for differentcluster sizes, new ab initio calculations are carried out on the clustersfor n = 4-10. Geometric structures are optimized at the CCSD(T) levelwith cc-pVTZ (or cc-pVDZ) basis sets, and focal point extrapolations areapplied to both neutral and cation species to determine adiabatic andvertical ionization potentials. The comparison of computed and measuredionization potentials makes it possible to investigate the isomericstructures of the neutral clusters produced in this experiment. Themeasurements are inconclusive for the n = 4-6 species because ofunquenched excited electronic states. However, the data provide evidencefor the prominence of linear structures for the n = 7, 9, 11, 13 speciesand the presence of cyclic C10.

  20. Analytical instruments, ionization sources, and ionization methods

    DOE Patents [OSTI]

    Atkinson, David A.; Mottishaw, Paul

    2006-04-11

    Methods and apparatus for simultaneous vaporization and ionization of a sample in a spectrometer prior to introducing the sample into the drift tube of the analyzer are disclosed. The apparatus includes a vaporization/ionization source having an electrically conductive conduit configured to receive sample particulate which is conveyed to a discharge end of the conduit. Positioned proximate to the discharge end of the conduit is an electrically conductive reference device. The conduit and the reference device act as electrodes and have an electrical potential maintained between them sufficient to cause a corona effect, which will cause at least partial simultaneous ionization and vaporization of the sample particulate. The electrical potential can be maintained to establish a continuous corona, or can be held slightly below the breakdown potential such that arrival of particulate at the point of proximity of the electrodes disrupts the potential, causing arcing and the corona effect. The electrical potential can also be varied to cause periodic arcing between the electrodes such that particulate passing through the arc is simultaneously vaporized and ionized. The invention further includes a spectrometer containing the source. The invention is particularly useful for ion mobility spectrometers and atmospheric pressure ionization mass spectrometers.

  1. Development and evaluation of supercritical fluid chromatography/mass spectrometry for polar and high-molecular-weight coal components. Technical progress report

    SciTech Connect (OSTI)

    Chess, E.K.; Smith, R.D.

    1986-01-01

    This Technical Progress Report reviews the technical progress made over the first 18 months of the program. Our goals include the design, development, and evaluation of a combined capillary column supercritical fluid chromatograph/high-performance mass spectrometer capable of analyzing high-molecular-weight polar materials and evaluating the system's potential for application in coal conversion process monitoring. The program includes not only the development and evaluation of the required instrumentation, but the development of polar fluids and compatible chromatographic stationary phases needed for efficient separation and analysis of polar and high-molecular-weight compounds. A new chromatograph/mass spectrometer interface and new mass spectrometer ion source have been designed, constructed, and evaluated using low-polarity supercritical fluids such as pentane. Results from the evaluations have been used to modify the instrumentation to improve performance. The design and fabrication of capillary flow restrictors from fused silica tubing has been explored. Research has also been conducted toward advancing the technology of fabricating high-performance chromatographic columns suitable for use with polar supercritical fluids. Results to date support our initial belief that high-resolution supercritical fluid chromatography (SFC)/high-performance mass spectrometry (MS) will provide a significantly enhanced analytical capability for broad classes of previously intractable fuel components. 10 refs., 13 figs.

  2. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    SciTech Connect (OSTI)

    LaFerriere, Brian D.; Maiti, Tapas C.; Arnquist, Isaac J.; Hoppe, Eric W.

    2015-03-01

    This study describes a novel sample preparation and assay method developed in support of the MAJORANA DEMONSTRATOR experiment for the determination of thorium and uranium levels in copper and lead shielding components. Meticulously clean sample preparation methods combined with novel anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg 232Th/g and 0.0106 pg 238U/g were determined for copper, while detection limits of 0.23 pg 232Th/g and 0.46 pg 238U/g were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment’s stringent radiopurity requirements are met.

  3. Laser ablation-inductively coupled plasma-mass spectrometry: Examinations of the origins of polyatomic ions and advances in the sampling of particulates

    SciTech Connect (OSTI)

    Witte, Travis

    2011-01-01

    This dissertation provides a general introduction to Inductively coupled plasma-mass spectrometry (ICP-MS) and laser ablation (LA) sampling, with an examination of analytical challenges in the employment of this technique. It discusses the origin of metal oxide ions (MO+) in LA-ICP-MS, as well as the effect of introducing helium and nitrogen to the aerosol gas flow on the formation of these polyatomic interferences. It extends the study of polyatomic ions in LA-ICP-MS to metal argide (MAr+) species, an additional source of possible significant interferences in the spectrum. It describes the application of fs-LA-ICP-MS to the determination of uranium isotope ratios in particulate samples.

  4. Demonstration of femtosecond laser ablation inductively coupled plasma mass spectrometry for uranium isotopic measurements in U-10Mo nuclear fuel foils

    SciTech Connect (OSTI)

    Havrilla, George Joseph; Gonzalez, Jhanis

    2015-06-10

    The use of femtosecond laser ablation inductively coupled plasma mass spectrometry was used to demonstrate the feasibility of measuring the isotopic ratio of uranium directly in U-10Mo fuel foils. The measurements were done on both the flat surface and cross sections of bare and Zr clad U-10Mo fuel foil samples. The results for the depleted uranium content measurements were less than 10% of the accepted U235/238 ratio of 0.0020. Sampling was demonstrated for line scans and elemental mapping over large areas. In addition to the U isotopic ratio measurement, the Zr thickness could be measured as well as trace elemental composition if required. A number of interesting features were observed during the feasibility measurements which could provide the basis for further investigation using this methodology. The results demonstrate the feasibility of using fs-LA-ICP-MS for measuring the U isotopic ratio in U-10Mo fuel foils.

  5. Production and isolation of homologs of flerovium and element 115 at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry

    SciTech Connect (OSTI)

    Despotopulos, John D.; Kmak, Kelly N.; Gharibyan, Narek; Brown, Thomas A.; Grant, Patrick M.; Henderson, Roger A.; Moody, Kent J.; Tumey, Scott J.; Shaughnessy, Dawn A.; Sudowe, Ralf

    2015-10-01

    Here, new procedures have been developed to isolate no-carrier-added (NCA) radionuclides of the homologs and pseudo-homologs of flerovium (Hg, Sn) and element 115 (Sb), produced by 12–15 MeV proton irradiation of foil stacks with the tandem Van-de-Graaff accelerator at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry (CAMS) facility. The separation of 113Sn from natIn foil was performed with anion-exchange chromatography from hydrochloric and nitric acid matrices. A cation-exchange chromatography method based on hydrochloric and mixed hydrochloric/hydroiodic acids was used to separate 124Sb from natSn foil. A procedure using Eichrom TEVA resin was developed to separate 197Hg from Au foil. These results demonstrate the suitability of using the CAMS facility to produce NCA radioisotopes for studies of transactinide homologs.

  6. Production and isolation of homologs of flerovium and element 115 at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Despotopulos, John D.; Kmak, Kelly N.; Gharibyan, Narek; Brown, Thomas A.; Grant, Patrick M.; Henderson, Roger A.; Moody, Kent J.; Tumey, Scott J.; Shaughnessy, Dawn A.; Sudowe, Ralf

    2015-10-01

    Here, new procedures have been developed to isolate no-carrier-added (NCA) radionuclides of the homologs and pseudo-homologs of flerovium (Hg, Sn) and element 115 (Sb), produced by 12–15 MeV proton irradiation of foil stacks with the tandem Van-de-Graaff accelerator at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry (CAMS) facility. The separation of 113Sn from natIn foil was performed with anion-exchange chromatography from hydrochloric and nitric acid matrices. A cation-exchange chromatography method based on hydrochloric and mixed hydrochloric/hydroiodic acids was used to separate 124Sb from natSn foil. A procedure using Eichrom TEVA resin was developed to separate 197Hg frommore » Au foil. These results demonstrate the suitability of using the CAMS facility to produce NCA radioisotopes for studies of transactinide homologs.« less

  7. Application of multivariate statistical analysis methods for improved time-of-flight secondary ion mass spectrometry depth profiling of buried interfaces and particulate

    SciTech Connect (OSTI)

    Lloyd, K. G.

    2007-07-15

    Buried irregular interfaces and particulate present special challenges in terms of chemical analysis and identification, and are critical issues in the manufacture of electronic materials and devices. Cross sectioning at the right location is often difficult, and, while dual-beam scanning electron microscopy/focused ion beam instruments can often provide excellent visualization of buried defects, matching chemical analysis may be absent or problematic. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling, with its ability to acquire spatially resolved depth profiles while collecting an entire mass spectrum at every 'voxel,' offers a way to revisit the problem of buried defects. Multivariate analysis of the overwhelming amount of data can reduce the output from essentially a depth profile at every mass to a small set of chemically meaningful factors. Data scaling is an important consideration in the application of these methods, and a comparison of scaling procedures is shown. Examples of ToF-SIMS depth profiles of relatively homogeneous layers, severely inhomogeneous layers, and buried particulate are discussed.

  8. Ion mass spectrometry investigations of the discharge during reactive high power pulsed and direct current magnetron sputtering of carbon in Ar and Ar/N{sub 2}

    SciTech Connect (OSTI)

    Schmidt, S.; Greczynski, G.; Jensen, J.; Hultman, L.; Czigany, Zs.

    2012-07-01

    Ion mass spectrometry was used to investigate discharges formed during high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a graphite target in Ar and Ar/N{sub 2} ambient. Ion energy distribution functions (IEDFs) were recorded in time-averaged and time-resolved mode for Ar{sup +}, C{sup +}, N{sub 2}{sup +}, N{sup +}, and C{sub x}N{sub y}{sup +} ions. An increase of N{sub 2} in the sputter gas (keeping the deposition pressure, pulse width, pulse frequency, and pulse energy constant) results for the HiPIMS discharge in a significant increase in C{sup +}, N{sup +}, and CN{sup +} ion energies. Ar{sup +}, N{sub 2}{sup +}, and C{sub 2}N{sup +} ion energies, in turn, did not considerably vary with the changes in working gas composition. The HiPIMS process showed higher ion energies and fluxes, particularly for C{sup +} ions, compared to DCMS. The time evolution of the plasma species was analyzed for HiPIMS and revealed the sequential arrival of working gas ions, ions ejected from the target, and later during the pulse-on time molecular ions, in particular CN{sup +} and C{sub 2}N{sup +}. The formation of fullerene-like structured CN{sub x} thin films for both modes of magnetron sputtering is explained by ion mass-spectrometry results and demonstrated by transmission electron microscopy as well as diffraction.

  9. A Novel Phase-Coherent Programmable Clock for High-Precision Arbitrary Waveform Generation Applied to Digital Ion Trap Mass Spectrometry

    SciTech Connect (OSTI)

    Koizumi, Hideya; Jatko, William Bruce; Andrews Jr, William H; Whitten, William B; Reilly, Pete

    2010-01-01

    Digital ion trap (DIT) mass spectrometry requires the ability to precisely and accurately produce waveforms. The quality of the mass spectra produced in terms of resolution and mass accuracy depend on the resolution and precision of the applied waveforms. This publication reveals a novel method for the production of arbitrary waveforms in general and then applies the method to the production of DIT waveforms. Arbitrary waveforms can be created by varying the clock frequency input to a programmable read only memory that is then input to a digital-to-analog converter (DAC). The arbitrary waveform is composed of a defined number of points that are triggered to be written after programmed numbers of clock cycles to define the arbitrary waveform. The novelty introduced here is that the direct digital synthesis (DDS) generated clock frequency can be precisely changed as the arbitrary waveform is written because we have developed a method to rapidly switch the DDS frequency exactly at the end of the output clock cycle allowing exact timing of multiple transitions to produce precise and temporally complex waveforms. Changing the frequency only at the end of the output clock cycle is a phase coherent process that permits precise timing between each point in the arbitrary waveform. The waveform generation technique was demonstrated by creating a prototype that was used to operate a digital ion trap mass spectrometer. The jitter in the phase-coherent DDS TTL output that was used as the frequency variable clock was 20 ps. This jitter represents the realizable limit of precision for waveform generation. The rectangular waveforms used to operate the mass spectrometer were created with counters that increased the jitter to 100 ps. The mass resolution achieved was 5000 at m/z = 414. This resolution corresponds to a jitter of 275 ps assuming DC fluctuations and overshoots in the waveform are insignificant. Resolution should improve with increasing mass because the waveforms have

  10. Final Technical Report for DE-FG02-06ER15835: Chemical Imaging with 100nm Spatial Resolution: Combining High Resolution Flurosecence Microscopy and Ion Mobility Mass Spectrometry

    SciTech Connect (OSTI)

    Buratto, Steven K.

    2013-09-03

    We have combined, in a single instrument, high spatial resolution optical microscopy with the chemical specificity and conformational selectivity of ion mobility mass spectrometry. We discuss the design and construction of this apparatus as well as our efforts in applying this technique to thin films of molecular semiconductor materials.

  11. Parallel Configuration For Fast Superconducting Strip Line Detectors With Very Large Area In Time Of Flight Mass Spectrometry

    SciTech Connect (OSTI)

    Casaburi, A.; Zen, N.; Suzuki, K.; Ohkubo, M.; Ejrnaes, M.; Cristiano, R.; Pagano, S.

    2009-12-16

    We realized a very fast and large Superconducting Strip Line Detector based on a parallel configuration of nanowires. The detector with size 200x200 {mu}m{sup 2} recorded a sub-nanosecond pulse width of 700 ps in FWHM (400 ps rise time and 530 ps relaxation time) for lysozyme monomers/multimers molecules accelerated at 175 keV in a Time of Flight Mass Spectrometer. This record is the best in the class of superconducting detectors and comparable with the fastest NbN superconducting single photon detector of 10x10 {mu}m{sup 2}. We succeeded in acquiring mass spectra as the first step for a scale-up to {approx}mm pixel size for high throughput MS analysis, while keeping a fast response.

  12. Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadrupole Mass Spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Tsung-Chi; Fillmore, Thomas L.; Prost, Spencer A.; Moore, Ronald J.; Ibrahim, Yehia M.; Smith, Richard D.

    2015-06-24

    The electrodynamic ion funnel facilitates efficient focusing and transfer of charged particles in the higher pressure regions (e.g. ion source interfaces) of mass spectrometers, and thus providing increased sensitivity. An “off-axis” ion funnel design has been developed to reduce the source contamination and interferences from, e.g. ESI droplet residue and other poorly focused neutral or charged particles with very high mass-to charge ratios. In this study a dual ion funnel interface consisting of an orthogonal higher pressure electrodynamic ion funnel (HPIF) and an ion funnel trap combined with a triple quadruple mass spectrometer was developed and characterized. An orthogonal ionmore » injection inlet and a repeller plate electrode was used to direct ions to an ion funnel HPIF at 9-10 Torr pressure. Several critical factors for the HPIF were characterized, including the effects of RF amplitude, DC gradient and operating pressure. Compared to the triple quadrupole standard interface more than 4-fold improvement in the limit of detection for the direct quantitative MS analysis of low abundance peptides was observed. Lastly, the sensitivity enhancement in liquid chromatography selected reaction monitoring (SRM) analyses of low abundance peptides spiked into a highly complex mixture was also compared with that obtained using a both commercial s-lens interface and a in-line dual ion funnel interface.« less

  13. Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadrupole Mass Spectrometry

    SciTech Connect (OSTI)

    Chen, Tsung-Chi; Fillmore, Thomas L.; Prost, Spencer A.; Moore, Ronald J.; Ibrahim, Yehia M.; Smith, Richard D.

    2015-06-24

    The electrodynamic ion funnel facilitates efficient focusing and transfer of charged particles in the higher pressure regions (e.g. ion source interfaces) of mass spectrometers, and thus providing increased sensitivity. An “off-axis” ion funnel design has been developed to reduce the source contamination and interferences from, e.g. ESI droplet residue and other poorly focused neutral or charged particles with very high mass-to charge ratios. In this study a dual ion funnel interface consisting of an orthogonal higher pressure electrodynamic ion funnel (HPIF) and an ion funnel trap combined with a triple quadruple mass spectrometer was developed and characterized. An orthogonal ion injection inlet and a repeller plate electrode was used to direct ions to an ion funnel HPIF at 9-10 Torr pressure. Several critical factors for the HPIF were characterized, including the effects of RF amplitude, DC gradient and operating pressure. Compared to the triple quadrupole standard interface more than 4-fold improvement in the limit of detection for the direct quantitative MS analysis of low abundance peptides was observed. Lastly, the sensitivity enhancement in liquid chromatography selected reaction monitoring (SRM) analyses of low abundance peptides spiked into a highly complex mixture was also compared with that obtained using a both commercial s-lens interface and a in-line dual ion funnel interface.

  14. Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadruple Mass Spectrometry

    SciTech Connect (OSTI)

    Chen, Tsung-Chi; Fillmore, Thomas L.; Prost, Spencer A.; Moore, Ronald J.; Ibrahim, Yehia M.; Smith, Richard D.

    2015-07-21

    The electrodynamic ion funnel facilitates efficient focusing and transfer of charged particles in the higher pressure regions (e.g. ion source interfaces) of mass spectrometers, and thus providing increased sensitivity. An “off-axis” ion funnel design has been developed to reduce the source contamination and interferences from, e.g. ESI droplet residue and other poorly focused neutral or charged particles with very high mass-to charge ratios. In this study a dual ion funnel interface consisting of an orthogonal higher pressure electrodynamic ion funnel (HPIF) and an ion funnel trap combined with a triple quadruple mass spectrometer was developed and characterized. An orthogonal ion injection inlet and a repeller plate electrode was used to direct ions to an ion funnel HPIF at 9-10 Torr pressure. Several critical factors for the HPIF were characterized, including the effects of RF amplitude, DC gradient and operating pressure. Compared to the triple quadrupole standard interface more than 4-fold improvement in the limit of detection for the direct quantitative MS analysis of low abundance peptides was observed. The sensitivity enhancement in liquid chromatography selected reaction monitoring (SRM) analyses of low abundance peptides spiked into a highly complex mixture was also compared with that obtained using a both commercial s-lens interface and a in-line dual ion funnel interface.

  15. Applications of ICP magnetic sector multicollector mass spectrometry to basic energy research. Final report for period December 1st, 1993 - May 31st, 2000

    SciTech Connect (OSTI)

    Halliday, A.N.

    2002-05-01

    The primary aims of this research were threefold: to develop and utilize the new technique of multiple collector inductively coupled plasma mass spectrometry and apply it to problems in the earth, ocean, and environmental sciences; to develop new chronometers and improve existing chronometers to allow the accurate determination of the ages of geological features and processes; and to study natural fluid-mediated mass transfer processes and source of components in the crust and the oceans. This technique has now become the preferred method for the determination of the isotopic compositions of a variety of elements in the periodic table. The prototype instrument was used to explore a vast array of isotopic systems and demonstrate applicability to problems as different as the origin of the solar system and smelting methods in the Bronze Age. Highlights of the program are briefly summarized under the following topics: tungsten isotopes and the early solar system; trace siderophile and chalcophile element geochemistry; hafnium isotopes and the early development of the continents; evolution of lead isotopic compositions of the oceans; the isotopic composition and residence time of Hf in seawater; the isotopic compositions of Sr, Hf, Pb, and Nd in dust; U-Th disequilibrium dating of carbonates and soils; in situ U-Th disequilibrium dating of opal.

  16. AN INTEGRAL REACTOR PHYSICS EXPERIMENT TO INFER ACTINIDE CAPTURE CROSS-SECTIONS FROM THORIUM TO CALIFORNIUM WITH ACCELERATOR MASS SPECTROMETRY

    SciTech Connect (OSTI)

    G. Youinou; M. Salvatores; M. Paul; R. Pardo; G. Palmiotti; F. Kondev; G. Imel

    2010-04-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectroscopy (AMS) technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am and 248Cm.

  17. Airborne measurements of sulfur dioxide, dimethyl sulfide, carbon disulfide, and carbonyl sulfide by isotope dilution gas chromatography/mass spectrometry

    SciTech Connect (OSTI)

    Bandy, A.R.; Thornton, D.C.; Driedger, A.R. III [Drexel Univ., Philadelphia, PA (United States)

    1993-12-01

    A gas chromatograph/mass spectrometer is described for determining atmospheric sulfur dioxide, carbon disulfide, dimethyl sulfide, and carbonyl sulfide from aircraft and ship platforms. Isotopically labelled variants of each analyte were used as internal standards to achieve high precision. The lower limit of detection for each species for an integration time of 3 min was 1 pptv for sulfur dioxide and dimethyl sulfide and 0.2 pptv for carbon disulfide and carbonyl sulfide. All four species were simultaneously determined with a sample frequency of one sample per 6 min or greater. When only one or two species were determined, a frequency of one sample per 4 min was achieved. Because a calibration is included in each sample, no separate calibration sequence was needed. Instrument warmup was only a few minutes. The instrument was very robust in field deployments, requiring little maintenance.

  18. Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges

    SciTech Connect (OSTI)

    Stranak, Vitezslav; Hubicka, Zdenek; Cada, Martin; Drache, Steffen; Hippler, Rainer; Tichy, Milan

    2014-04-21

    The metal ionized flux fraction and production of double charged metal ions Me{sup 2+} of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ξ. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me{sup 2+} and singly Me{sup +} charged metal ions was determined. It is shown that ECWR assistance enhances Me{sup 2+} production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me{sup 2+} was observed.

  19. Ionization chamber

    DOE Patents [OSTI]

    Walenta, Albert H.

    1981-01-01

    An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

  20. Ionization chamber

    DOE Patents [OSTI]

    Walenta, A.H.

    An ionization chamber is described which has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionizes the gas.

  1. IONIZATION CHAMBER

    DOE Patents [OSTI]

    Redman, W.C.; Shonka, F.R.

    1958-02-18

    This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

  2. Design and performance of a combined secondary ion mass spectrometry-scanning probe microscopy instrument for high sensitivity and high-resolution elemental three-dimensional analysis

    SciTech Connect (OSTI)

    Wirtz, Tom; Fleming, Yves; Gerard, Mathieu; Gysin, Urs; Glatzel, Thilo; Meyer, Ernst; Wegmann, Urs; Maier, Urs; Odriozola, Aitziber Herrero; Uehli, Daniel

    2012-06-15

    State-of-the-art secondary ion mass spectrometry (SIMS) instruments allow producing 3D chemical mappings with excellent sensitivity and spatial resolution. Several important artifacts however arise from the fact that SIMS 3D mapping does not take into account the surface topography of the sample. In order to correct these artifacts, we have integrated a specially developed scanning probe microscopy (SPM) system into a commercial Cameca NanoSIMS 50 instrument. This new SPM module, which was designed as a DN200CF flange-mounted bolt-on accessory, includes a new high-precision sample stage, a scanner with a range of 100 {mu}m in x and y direction, and a dedicated SPM head which can be operated in the atomic force microscopy (AFM) and Kelvin probe force microscopy modes. Topographical information gained from AFM measurements taken before, during, and after SIMS analysis as well as the SIMS data are automatically compiled into an accurate 3D reconstruction using the software program 'SARINA,' which was developed for this first combined SIMS-SPM instrument. The achievable lateral resolutions are 6 nm in the SPM mode and 45 nm in the SIMS mode. Elemental 3D images obtained with our integrated SIMS-SPM instrument on Al/Cu and polystyrene/poly(methyl methacrylate) samples demonstrate the advantages of the combined SIMS-SPM approach.

  3. Determination of trace lanthanides and yttrium in seawater by inductively coupled plasma mass spectrometry after preconcentration with solvent extraction and back-extraction

    SciTech Connect (OSTI)

    Shabani, M.B.; Akagi, Tasuku; Shimizu, Hiroshi; Masuda, Akimasa )

    1990-12-15

    A method for the analysis of sub parts per trillion levels of rare-earth elements (REEs) and yttrium (Y) in seawater after preconcentration with solvent extraction and back-extraction has been developed. Almost perfect extraction and back-extraction of all REE and Y were achieved by single extraction, and most of the matrix elements were removed during the extraction procedure. Even after 200-fold preconcentration, matrix problems by ICP-MS measurement were negligible. Contamination from reagents and water used during the pretreatment was below 1% of the concentration of REE and Y in seawater. The standard deviation obtained for triplicate separation of 100- and 1,000-mL samples of the same seawater was better than 5% for all REE. The average precision of the measurement for all REE and Y after preconcentration of 1,000 mL of raw seawater to 5 mL of final measurement solution was calculated to be less than 2.5%. Since there is no standard seawater sample for REE and Y, in order to evaluate this novel technique, the analytical results obtained by this method were compared with those obtained by isotope dilution mass spectrometry coupled with Fe coprecipitation.

  4. Review, evaluation, and discussion of the challenges of missing value imputation for mass spectrometry-based label-free global proteomics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Webb-Robertson, Bobbie-Jo M.; Wiberg, Holli K.; Matzke, Melissa M.; Brown, Joseph N.; Wang, Jing; McDermott, Jason E.; Smith, Richard D.; Rodland, Karin D.; Metz, Thomas O.; Pounds, Joel G.; et al

    2015-04-09

    In this review, we apply selected imputation strategies to label-free liquid chromatography–mass spectrometry (LC–MS) proteomics datasets to evaluate the accuracy with respect to metrics of variance and classification. We evaluate several commonly used imputation approaches for individual merits and discuss the caveats of each approach with respect to the example LC–MS proteomics data. In general, local similarity-based approaches, such as the regularized expectation maximization and least-squares adaptive algorithms, yield the best overall performances with respect to metrics of accuracy and robustness. However, no single algorithm consistently outperforms the remaining approaches, and in some cases, performing classification without imputation sometimes yieldedmore » the most accurate classification. Thus, because of the complex mechanisms of missing data in proteomics, which also vary from peptide to protein, no individual method is a single solution for imputation. In summary, on the basis of the observations in this review, the goal for imputation in the field of computational proteomics should be to develop new approaches that work generically for this data type and new strategies to guide users in the selection of the best imputation for their dataset and analysis objectives.« less

  5. Identification of volatile butyl rubber thermal-oxidative degradation products by cryofocusing gas chromatography/mass spectrometry (cryo-GC/MS).

    SciTech Connect (OSTI)

    Smith, Jonell Nicole; White, Michael Irvin; Bernstein, Robert; Hochrein, James Michael

    2013-02-01

    Chemical structure and physical properties of materials, such as polymers, can be altered as aging progresses, which may result in a material that is ineffective for its envisioned intent. Butyl rubber formulations, starting material, and additives were aged under thermal-oxidative conditions for up to 413 total days at up to 124 %C2%B0C. Samples included: two formulations developed at Kansas City Plant (KCP) (%236 and %2310), one commercially available formulation (%2321), Laxness bromobutyl 2030 starting material, and two additives (polyethylene AC-617 and Vanax MBM). The low-molecular weight volatile thermal-oxidative degradation products that collected in the headspace over the samples were preconcentrated, separated, and detected using cryofocusing gas chromatography mass spectrometry (cryo-GC/MS). The majority of identified degradation species were alkanes, alkenes, alcohols, ketones, and aldehydes. Observations for Butyl %2310 aged in an oxygen-18 enriched atmosphere (18O2) were used to verify when the source of oxygen in the applicable degradation products was from the gaseous environment rather than the polymeric mixture. For comparison purposes, Butyl %2310 was also aged under non-oxidative thermal conditions using an argon atmosphere.

  6. Structure and Dynamics of NBD1 from CFTR Characterized Using Crystallography and Hydrogen/Deuterium Exchange Mass Spectrometry

    SciTech Connect (OSTI)

    Lewis, H.A.; Wang, C.; Zhao, X.; Hamuro, Y.; Conners, K.; Kearins, M.C.; Lu, F.; Sauder, J.M.; Molnar, K.S.; Coales, S.J.; Maloney, P.C.; Guggino, W.B.; Wetmore, D.R.; Weber, P.C.; Hunt, J.F. (SGX); (ExSAR); (Cystic); (JHU-MED); (Columbia)

    2012-04-30

    The {Delta}F508 mutation in nucleotide-binding domain 1 (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR) is the predominant cause of cystic fibrosis. Previous biophysical studies on human F508 and {Delta}F508 domains showed only local structural changes restricted to residues 509-511 and only minor differences in folding rate and stability. These results were remarkable because {Delta}F508 was widely assumed to perturb domain folding based on the fact that it prevents trafficking of CFTR out of the endoplasmic reticulum. However, the previously reported crystal structures did not come from matched F508 and {Delta}F508 constructs, and the {Delta}F508 structure contained additional mutations that were required to obtain sufficient protein solubility. In this article, we present additional biophysical studies of NBD1 designed to address these ambiguities. Mass spectral measurements of backbone amide {sup 1}H/{sup 2}H exchange rates in matched F508 and {Delta}F508 constructs reveal that {Delta}F508 increases backbone dynamics at residues 509-511 and the adjacent protein segments but not elsewhere in NBD1. These measurements also confirm a high level of flexibility in the protein segments exhibiting variable conformations in the crystal structures. We additionally present crystal structures of a broader set of human NBD1 constructs, including one harboring the native F508 residue and others harboring the {Delta}F508 mutation in the presence of fewer and different solubilizing mutations. The only consistent conformational difference is observed at residues 509-511. The side chain of residue V510 in this loop is mostly buried in all non-{Delta}F508 structures but completely solvent exposed in all {Delta}F508 structures. These results reinforce the importance of the perturbation {Delta}F508 causes in the surface topography of NBD1 in a region likely to mediate contact with the transmembrane domains of CFTR. However, they also suggest that increased

  7. Rapid and sensitive gas chromatography ion-trap mass spectrometry method for the determination of tobacco specific N-nitrosamines in secondhand smoke

    SciTech Connect (OSTI)

    SLEIMAN, Mohamad; MADDALENA, Randy L.; GUNDEL, Lara A.; DESTAILLATS, Hugo

    2009-07-01

    Tobacco-specific nitrosamines (TSNAs) are some of the most potent carcinogens in tobacco and cigarette smoke. Accurate quantification of these chemicals is needed to help assess public health risks. We developed and validated a specific and sensitive method to measure four TSNAs in both the gas- and particle-phase of secondhand smoke (SHS) using gas chromatography and ion-trap tandem mass spectrometry,. A smoking machine in an 18-m3 room-sized chamber generated relevant concentrations of SHS that were actively sampled on Teflon coated fiber glass (TCFG) filters, and passively sampled on cellulose substrates. A simple solid-liquid extraction protocol using methanol as solvent was successfully applied to both filters with high recoveries ranging from 85 to 115percent. Tandem MS parameters were optimized to obtain the best sensitivity in terms of signal to-noise ratio (S/N) for the target compounds. For each TSNA, the major fragmentation pathways as well as ion structures were elucidated and compared with previously published data. The method showed excellent performances with a linear dynamic range between 2 and 1000 ng mL-1, low detection limits (S/N> 3) of 30-300 pg.ml-1 and precision with experimental errors below 10percent for all compounds. Moreover, no interfering peaks were observed indicating a high selectivity of MS/MS without the need for a sample clean up step. The sampling and analysis method provides a sensitive and accurate tool to detect and quantify traces of TSNA in SHS polluted indoor environments.

  8. Investigating Enhanced Thorium Ionization in TIMS Using Re/Pt Porous Ion Emitters

    SciTech Connect (OSTI)

    Floyd E. Stanley III; K. J. Spencer; D. S. Schwartz; M. G. Watrous; J. E. Delmore

    2014-03-01

    Thermal ionization mass spectrometry (TIMS) is a widely used, benchmark method in the isotopic analysis of actinides relevant to various nuclear and geological fields. Despite significant previous use and inherent advantages, however, poor sample ionization continues to hamper the use of TIMS in the measurement of trace species; actinide ionization efficiencies frequently fall below 0.1 % using traditional instrument sources. Factors leading to poor ionization are compounded in the measurement of several highly refractory metals (e.g. U and Th) that may provide key signatures data in non-proliferation, safeguards and forensics efforts. Herein, a relatively new TIMS ion source strategy, employing porous ion emitters (PIEs) atop traditional filament assemblies, is investigated for the first time as a straightforward means of enhancing the ionization of Th, which is arguably a worst case scenario for TIMS-based actinide measurements. These sources yielded up to 410% greater Th sample utilization, relative to previously published values and in-house measurements collected using traditional methods. Accompanying scanning electron microscopy (SEM) investigations provide preliminary insight into possible mechanisms of PIE functioning and explore the impacts that extended heating have on the constructed source’s structure and composition.

  9. On the Ionization and Ion Transmission Efficiencies of Different ESI-MS Interfaces

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cox, Jonathan T.; Marginean, Ioan; Smith, Richard D.; Tang, Keqi

    2014-09-30

    It is well known that the achievable sensitivity of electrospray ionization mass spectrometry (ESI-MS) is largely determined by the ionization efficiency in the ESI source and ion transmission efficiency through the ESI-MS interface. In this report we systematically study the ion transmission and ionization efficiencies in different ESI-MS interface configurations. The configurations under investigation include a single emitter/single inlet capillary, single emitter/multi-inlet capillary, and a subambient pressure ionization with nanoelectrospray (SPIN) MS interfaces with a single emitter and an emitter array, respectively. We present an effective method to evaluate the overall ion utilization efficiency of an ESI-MS interface by measuringmore » the total gas phase ion current transmitted through the interface and correlating it to the observed ion abundance measured in the corresponding mass spectrum. Our experimental results suggest that the overall ion utilization efficiency in the SPIN-MS interface configurations is better than that in the inlet capillary based ESI-MS interface configurations.« less

  10. On the Ionization and Ion Transmission Efficiencies of Different ESI-MS Interfaces

    SciTech Connect (OSTI)

    Cox, Jonathan T.; Marginean, Ioan; Smith, Richard D.; Tang, Keqi

    2014-09-30

    It is well known that the achievable sensitivity of electrospray ionization mass spectrometry (ESI-MS) is largely determined by the ionization efficiency in the ESI source and ion transmission efficiency through the ESI-MS interface. In this report we systematically study the ion transmission and ionization efficiencies in different ESI-MS interface configurations. The configurations under investigation include a single emitter/single inlet capillary, single emitter/multi-inlet capillary, and a subambient pressure ionization with nanoelectrospray (SPIN) MS interfaces with a single emitter and an emitter array, respectively. We present an effective method to evaluate the overall ion utilization efficiency of an ESI-MS interface by measuring the total gas phase ion current transmitted through the interface and correlating it to the observed ion abundance measured in the corresponding mass spectrum. Our experimental results suggest that the overall ion utilization efficiency in the SPIN-MS interface configurations is better than that in the inlet capillary based ESI-MS interface configurations.

  11. Ionization of cytosine monomer and dimer studied by VUV photoionization and electronic structure calculations

    SciTech Connect (OSTI)

    Kostko, Oleg; Bravaya, Ksenia; Krylov, Anna; Ahmed, Musahid

    2009-12-14

    We report a combined theoretical and experimental study of ionization of cytosine monomers and dimers. Gas-phase molecules are generated by thermal vaporization of cytosine followed by expansion of the vapor in a continuous supersonic jet seeded in Ar. The resulting species are investigated by single photon ionization with tunable vacuum-ultraviolet (VUV) synchrotron radiation and mass analyzed using reflectron mass spectrometry. Energy onsets for the measured photoionization efficiency (PIE) spectra are 8.60+-0.05 eV and 7.6+-0.1 eV for the monomer and the dimer, respectively, and provide an estimate for the adiabatic ionization energies (AIE). The first AIE and the ten lowest vertical ionization energies (VIEs) for selected isomers of cytosine dimer computed using equation-of-motion coupled-cluster (EOM-IP-CCSD) method are reported. The comparison of the computed VIEs with the derivative of the PIE spectra, suggests that multiple isomers of the cytosine dimer are present in the molecular beam. The calculations reveal that the large red shift (0.7 eV) of the first IE of the lowest-energy cytosine dimer is due to strong inter-fragment electrostatic interactions, i.e., the hole localized on one of the fragments is stabilized by the dipole moment of the other. A sharp rise in the CH+ signal at 9.20+-0.05 eV is ascribed to the formation of protonated cytosine by dissociation of the ionized dimers. The dominant role of this channel is supported by the computed energy thresholds for the CH+ appearance and the barrierless or nearly barrierless ionization-induced proton transfer observed for five isomers of the dimer.

  12. Wavelength and Intensity Dependence of Short Pulse Laser Xenon Double Ionization between 500 and 2300 nm

    SciTech Connect (OSTI)

    Gingras, G.; Tripathi, A.; Witzel, B.

    2009-10-23

    The wavelength and intensity dependence of xenon ionization with 50 fs laser pulses has been studied using time-of-flight mass spectrometry. We compare the ion yield distribution of singly and doubly charged xenon with the Perelomov-Popov-Terent'ev (PPT) theory, Perelomov, Popov, and Terent'ev, Zh. Eksp. Teor. Fiz. 50, 1393 (1966) [Sov. Phys. JETP 23, 924 (1966)], in the regime between 500 and 2300 nm. The intensity dependence for each wavelength is measured in a range between 1x10{sup 13} and 1x10{sup 15} W/cm{sup 2}. The Xe{sup +}-ion signal is in good agreement with the PPT theory at all used wavelengths. In addition we demonstrate that ionic 5s5p{sup 6} {sup 2}S state is excited by an electron impact excitation process and contributes to the nonsequential double ionization process.

  13. Atmospheric sampling glow discharge ionization source

    DOE Patents [OSTI]

    McLuckey, S.A.; Glish, G.L.

    1989-07-18

    An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

  14. Atmospheric sampling glow discharge ionization source

    DOE Patents [OSTI]

    McLuckey, Scott A. (Oak Ridge, TN); Glish, Gary L. (Oak Ridge, TN)

    1989-01-01

    An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above.

  15. Time and space resolved measurement of the electron temperature, mass density and ionization state in the ablation plasma between two exploding Al wires

    SciTech Connect (OSTI)

    Knapp, P. F.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Hansen, S. B.

    2012-05-15

    We have determined the properties of plasma around and between two exploding wires using high-resolution x-ray absorption spectroscopy. Plasma densities and temperatures ranging from Greater-Than-Or-Equivalent-To 0.1g/cm{sup 3} and a few eV to less than 0.01 g/cm{sup 3} and 30 eV have been measured in experiments at Cornell University with two 40 {mu}m aluminum (Al) wires spaced 1 mm apart driven by {approx}150 kA peak current pulses with 100 ns rise time. The wire plasma was backlit by the 1.4-1.6 keV continuum radiation produced by a Mo wire X-pinch. The spectrometer employed two spherically bent quartz crystals to record the absorption and backlighter spectra simultaneously. The transition between the dense Al wire core and the coronal plasma is seen as a transition from cold K-edge absorption to Mg-, Na-, and finally Ne-like absorption at the boundary. In the plasma that accumulates between the wires, ionization states up to C-Like Al are observed. The spectrometer geometry and {approx}2{mu}m X-pinch source size provide 0.3 eV spectral resolution and 20 {mu}m spatial resolution enabling us to see 1s{yields} 2p satellite transitions as separate lines as well as O-, F-, and Ne-like 1s{yields} 3p transitions that have not been seen before. A step wedge was used to calibrate the transmission, enabling density to be measured within a factor of two and temperature to be measured within {+-}25%. A genetic algorithm was developed to fit synthetic spectra calculated using the collisional-radiative code SCRAM to the experimental spectra. In order to obtain agreement it was necessary to assume multiple plasma regions with variable thicknesses, thereby allowing the inferred plasma conditions to vary along the absorption path.

  16. Current developments in laser ablation-inductively coupled plasma-mass spectrometry for use in geology, forensics, and nuclear nonproliferation research

    SciTech Connect (OSTI)

    Messerly, Joshua D.

    2008-08-26

    This dissertation focused on new applications of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The diverse fields that were investigated show the versatility of the technique. In Chapter 2, LA-ICP-MS was used to investigate the rare earth element (REE) profiles of garnets from the Broken Hill Deposit in New South Wales, Australia. The normalized REE profiles helped to shed new light on the formation of deposits of sulfide ores. This information may be helpful in identifying the location of sulfide ore deposits in other locations. New sources of metals such as Pg, Zn, and Ag, produced from these ores, are needed to sustain our current technological society. The application of LA-ICP-MS presented in Chapter 3 is the forensics analysis of automotive putty and caulking. The elemental analysis of these materials was combined with the use of Principal Components Analysis (PCA). The PCA comparison was able to differentiate the automotive putty samples by manufacturer and lot number. The analysis of caulk was able to show a differentiation based on manufacturer, but no clear differentiation was shown by lot number. This differentiation may allow matching of evidence in the future. This will require many more analyses and the construction of a database made up of many different samples. The 4th chapter was a study of the capabilities of LA-ICP-MS for fast and precise analysis of particle ensembles for nuclear nonproliferation applications. Laser ablation has the ability to spatially resolve particle ensembles which may contain uranium or other actinides from other particles present in a sample. This is of importance in samples obtained from air on filter media. The particle ensembles of interest may be mixed in amongst dust and other particulates. A problem arises when ablating these particle ensembles directly from the filter media. Dust particles other than ones of interest may be accidentally entrained in the aerosol of the ablated particle

  17. Characterisation of amorphous silica in air-oxidised Ti3SiC2 at 500-1000 °C using secondary-ion mass spectrometry, nuclear magnetic resonance and transmission electron microscopy

    SciTech Connect (OSTI)

    Pang, W K; Low, I M; Hanna, J V

    2010-05-18

    In this paper we have described the use of secondary-ion mass spectrometry (SIMS), solid state {sup 29}Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti{sub 3}SiC{sub 2} oxidised at 500-1000 C. The formation of amorphous SiO{sub 2} and growth of crystalline TiO{sub 2} with temperature was monitored using dynamic SIMS and synchrotron radiation diffraction. A duplex structure with an outer TiO{sub 2}-rich layer and an inner mixed layer of SiO{sub 2} and TiO{sub 2} was observed. Results of NMR and TEM verified for the first time the direct evidence of amorphous silica formation during the oxidation of Ti{sub 3}SiC{sub 2} at the temperature range 500-1000 C.

  18. Characterization of Ambient Aerosols in Mexico City during the MCMA-2003 Campaign with Aerosol Mass Spectrometry. Results from the CENICA Supersite

    SciTech Connect (OSTI)

    Salcedo, D.; Onasch, Timothy B.; Dzepina, K.; Canagaratna, M. R.; Zhang, Q.; Huffman, A. J.; DeCarlo, Peter; Jayne, J. T.; Mortimer, P.; Worsnop, Douglas R.; Kolb, C. E.; Johnson, Kirsten S.; Zuberi, Bilal M.; Marr, L.; Volkamer, Rainer M.; Molina, Luisa; Molina, Mario J.; Cardenas, B.; Bernabe, R.; Marquez, C.; Gaffney, Jeffrey S.; Marley, Nancy A.; Laskin, Alexander; Shutthanandan, V.; Xie, YuLong; Brune, W. H.; Lesher, R.; Shirley, T.; Jiminez, J. L.

    2006-03-24

    An Aerodyne Aerosol Mass Spectrometer (AMS) was deployed at the CENICA Supersite, while another was deployed in the Aerodyne Mobile Laboratory (AML) during the Mexico City Metropolitan Area field study (MCMA-2003) from March 29-May 4, 2003 to investigate particle concentrations, sources, and processes. This is the first of a series of papers reporting the AMS results from this campaign. The AMS provides real time information on mass concentration and composition of the non-refractory species in particulate matter less than 1 ?m (NR PM1) with high time and size resolution. For the first time, we report field results from a beam width probe, which was used to study the shape and mixing state of the particles and to quantify potential losses of irregular particles due to beam broadening inside the AMS. Data from this probe show that no significant amount of irregular particles was lost due to excessive beam broadening. A comparison of the CENICA and AML AMSs measurements is presented, being the first published intercomparison between two quadrupole AMSs. The speciation, and mass concentrations reported by the two AMSs compared well. In order to account for the refractory material in the aerosol, we also present measurements of Black Carbon (BC) using an aethalometer and an estimate of the aerosol soil component obtained from PIXE analysis of filters. Comparisons of (AMS + BC + soil) mass concentration with other collocated particle instruments (a LASAIR Optical Particle Counter, a Tapered Element Oscillating Microbalance (TEOM) and a DustTrack Aerosol Monitor) are also presented. The comparisons show that the (AMS + BC + soil) mass concentration during MCMC-2003 is a good approximation to the total PM??? mass concentration.

  19. High and Low Doses of Ionizing Radiation Induce Different Secretome Profiles in a Human Skin Model

    SciTech Connect (OSTI)

    Zhang, Qibin; Matzke, Melissa M.; Schepmoes, Athena A.; Moore, Ronald J.; Webb-Robertson, Bobbie-Jo M.; Hu, Zeping; Monroe, Matthew E.; Qian, Weijun; Smith, Richard D.; Morgan, William F.

    2014-03-18

    It is postulated that secreted soluble factors are important contributors of bystander effect and adaptive responses observed in low dose ionizing radiation. Using multidimensional liquid chromatography-mass spectrometry based proteomics, we quantified the changes of skin tissue secretome the proteins secreted from a full thickness, reconstituted 3-dimensional skin tissue model 48 hr after exposure to 3, 10 and 200 cGy of X-rays. Overall, 135 proteins showed statistical significant difference between the sham (0 cGy) and any of the irradiated groups (3, 10 or 200 cGy) on the basis of Dunnett adjusted t-test; among these, 97 proteins showed a trend of downregulation and 9 proteins showed a trend of upregulation with increasing radiation dose. In addition, there were 21 and 8 proteins observed to have irregular trends with the 10 cGy irradiated group either having the highest or the lowest level among all three radiated doses. Moreover, two proteins, carboxypeptidase E and ubiquitin carboxyl-terminal hydrolase isozyme L1 were sensitive to ionizing radiation, but relatively independent of radiation dose. Conversely, proteasome activator complex subunit 2 protein appeared to be sensitive to the dose of radiation, as rapid upregulation of this protein was observed when radiation doses were increased from 3, to 10 or 200 cGy. These results suggest that different mechanisms of action exist at the secretome level for low and high doses of ionizing radiation.

  20. Electron Ionization Mass Spectrum of Tellurium Hexafluoride ...

    Office of Scientific and Technical Information (OSTI)

    Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were ...

  1. Ultra High Mass Range Mass Spectrometer System

    DOE Patents [OSTI]

    Reilly, Peter T. A. [Knoxville, TN

    2005-12-06

    Applicant's present invention comprises mass spectrometer systems that operate in a mass range from 1 to 10.sup.16 DA. The mass spectrometer system comprising an inlet system comprising an aerodynamic lens system, a reverse jet being a gas flux generated in an annulus moving in a reverse direction and a multipole ion guide; a digital ion trap; and a thermal vaporization/ionization detector system. Applicant's present invention further comprises a quadrupole mass spectrometer system comprising an inlet system having a quadrupole mass filter and a thermal vaporization/ionization detector system. Applicant's present invention further comprises an inlet system for use with a mass spectrometer system, a method for slowing energetic particles using an inlet system. Applicant's present invention also comprises a detector device and a method for detecting high mass charged particles.

  2. Accurate determination of Curium and Californium isotopic ratios by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) in 248Cm samples for transmutation studies

    SciTech Connect (OSTI)

    Gourgiotis, A.; Isnard, H.; Aubert, M.; Dupont, E.; AlMahamid, I.; Cassette, P.; Panebianco, S.; Letourneau, A.; Chartier, F.; Tian, G.; Rao, L.; Lukens, W.

    2011-02-01

    The French Atomic Energy Commission has carried out several experiments including the mini-INCA (INcineration of Actinides) project for the study of minor-actinide transmutation processes in high intensity thermal neutron fluxes, in view of proposing solutions to reduce the radiotoxicity of long-lived nuclear wastes. In this context, a Cm sample enriched in {sup 248}Cm ({approx}97 %) was irradiated in thermal neutron flux at the High Flux Reactor (HFR) of the Laue-Langevin Institute (ILL). This work describes a quadrupole ICP-MS (ICP-QMS) analytical procedure for precise and accurate isotopic composition determination of Cm before sample irradiation and of Cm and Cf after sample irradiation. The factors that affect the accuracy and reproducibility of isotopic ratio measurements by ICP-QMS, such as peak centre correction, detector dead time, mass bias, abundance sensitivity and hydrides formation, instrumental background, and memory blank were carefully evaluated and corrected. Uncertainties of the isotopic ratios, taking into account internal precision of isotope ratio measurements, peak tailing, and hydrides formations ranged from 0.3% to 1.3%. This uncertainties range is quite acceptable for the nuclear data to be used in transmutation studies.

  3. Impurity Profiling of a Chemical Weapon Precursor for Possible Forensic Signatures by Comprehensive Two-Dimensional Gas Chromatography/Mass Spectrometry and Chemometrics

    SciTech Connect (OSTI)

    Hoggard, Jamin C.; Wahl, Jon H.; Synovec, Robert E.; Mong, Gary M.; Fraga, Carlos G.

    2010-01-15

    In this work we present the feasibility of using analytical chemical and chemometric methodologies to reveal and exploit the organic impurity profiles from commercial dimethyl methylphosphonate (DMMP) samples to illustrate the type of forensic information that may be obtained from chemical-attack evidence. Using DMMP as a model compound for a toxicant that may be used in a chemical attack, we used comprehensive two-dimensional gas chromatography mass spectrometric detection (GC GC-TOFMS) to detect and identify trace organic impurities in six samples of commercially acquired DMMP. The GC x GC-TOFMS data were analyzed to produce impurity profiles for all six DMMP samples using 29 analyte impurities. The use of PARAFAC for the mathematical resolution of overlap GC x GC peaks ensured clean spectra for the identification of many of the detected analytes by spectral library matching. The use of statistical pairwise comparison revealed that there were trace impurities that were quantitatively similar and different among five of the six DMMP samples. Two of the DMMP samples were revealed to have identical impurity profiles by this approach. The use of nonnegative matrix factorization proved that there were five distinct DMMP sample types as illustrated by the clustering of the multiple DMMP analyses into 5 distinct clusters in the scores plots. The two indistinguishable DMMP samples were confirmed by their chemical supplier to be from the same bulk source. Sample information from the other chemical suppliers supported that the other five DMMP samples were likely from different bulk sources. These results demonstrate that the matching of synthesized products from the same source is possible using impurity profiling. In addition, the identified impurities common to all six DMMP samples provide strong evidence that basic route information can be obtained from impurity profiles. In addition, impurities that may be unique to the sole bulk manufacturer of DMMP were found in

  4. Biological Effects of Ionizing Radiation

    DOE R&D Accomplishments [OSTI]

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  5. High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback

    SciTech Connect (OSTI)

    Harold Schock; Farhad Jaberi; Ahmed Naguib; Guoming Zhu; David Hung

    2007-12-31

    This report describes the work completed over a two and one half year effort sponsored by the US Department of Energy. The goal was to demonstrate the technology needed to produce a highly efficient engine enabled by several technologies which were to be developed in the course of the work. The technologies included: (1) A low-pressure direct injection system; (2) A mass air flow sensor which would measure the net airflow into the engine on a per cycle basis; (3) A feedback control system enabled by measuring ionization current signals from the spark plug gap; and (4) An infinitely variable cam actuation system based on a pneumatic-hydraulic valve actuation These developments were supplemented by the use of advanced large eddy simulations as well as evaluations of fuel air mixing using the KIVA and WAVE models. The simulations were accompanied by experimental verification when possible. In this effort a solid base has been established for continued development of the advanced engine concepts originally proposed. Due to problems with the valve actuation system a complete demonstration of the engine concept originally proposed was not possible. Some of the highlights that were accomplished during this effort are: (1) A forward-backward mass air flow sensor has been developed and a patent application for the device has been submitted. We are optimistic that this technology will have a particular application in variable valve timing direct injection systems for IC engines. (2) The biggest effort on this project has involved the development of the pneumatic-hydraulic valve actuation system. This system was originally purchased from Cargine, a Swedish supplier and is in the development stage. To date we have not been able to use the actuators to control the exhaust valves, although the actuators have been successfully employed to control the intake valves. The reason for this is the additional complication associated with variable back pressure on the exhaust valves when

  6. Alkali metal ionization detector

    DOE Patents [OSTI]

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  7. Aerosol mass spectrometry systems and methods

    DOE Patents [OSTI]

    Fergenson, David P.; Gard, Eric E.

    2013-08-20

    A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

  8. Universal collisional activation ion trap mass spectrometry

    DOE Patents [OSTI]

    McLuckey, Scott A.; Goeringer, Douglas E.; Glish, Gary L.

    1993-01-01

    A universal collisional activation ion trap comprises an ion trapping means containing a bath gas and having connected thereto a noise signal generator. A method of operating a universal collisional activation ion trap comprises the steps of: providing an ion trapping means; introducing into the ion trapping means a bath gas; and, generating a noise signal within the ion trapping means; introducing into the ion trapping means a substance that, when acted upon by the noise signal, undergoes collisional activation to form product ions.

  9. Universal collisional activation ion trap mass spectrometry

    DOE Patents [OSTI]

    McLuckey, S.A.; Goeringer, D.E.; Glish, G.L.

    1993-04-27

    A universal collisional activation ion trap comprises an ion trapping means containing a bath gas and having connected thereto a noise signal generator. A method of operating a universal collisional activation ion trap comprises the steps of: providing an ion trapping means; introducing into the ion trapping means a bath gas; and, generating a noise signal within the ion trapping means; introducing into the ion trapping means a substance that, when acted upon by the noise signal, undergoes collisional activation to form product ions.

  10. CAMS Center for Accelerator Mass Spectrometry

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the art instrumentation, to develop and apply unique, ultra-sensitive isotope ratio measurement and ion beam analytical techniques to address a broad spectrum of scientific...

  11. A VUV photoionization measurement and ab-initio calculation of the ionization energy of gas phase SiO2

    SciTech Connect (OSTI)

    Kostko, Oleg; Ahmed, Musahid; Metz, Ricardo B.

    2008-12-05

    In this work we report on the detection and vacuum-ultraviolet (VUV) photoionization of gas phase SiO2 generated in situ via laser ablation of silicon in a CO2 molecular beam. The resulting species are investigated by single photon ionization with tunable VUV synchrotron radiation and mass analyzed using reflectron mass spectrometry. Photoionization efficiency (PIE) curves are recorded for SiO and SiO2 and ionization energy estimates are revealed from such measurements. A state-to-state ionizationenergy of 12.60 (+-0.05) eV is recorded by fitting two prominent peaks in the PIE curve for the following process: 1SUM O-Si-O --> 2PRODg [O-Si-O]+. Electronic structure calculations aid in the interpretation of the photoionization process and allow for identification of the symmetric stretch of 2PRODg [O-Si-O]+ which is observed in the PIE spectrum to be 0.11 eV (890 cm-1) above the ground state of the cation and agrees with the 892 cm-1 symmetric stretch frequency calculated at the CCSD(T)/aug-cc-pVTZ level.

  12. Charge Retention by Gold Clusters on Surfaces Prepared Using Soft Landing of Mass Selected Ions

    SciTech Connect (OSTI)

    Johnson, Grant E.; Priest, Thomas A.; Laskin, Julia

    2012-01-24

    Monodisperse gold clusters have been prepared on surfaces in different charge states through soft landing of mass-selected ions. Ligand-stabilized gold clusters were prepared in methanol solution by reduction of chloro(triphenylphosphine)gold(I) with borane tert-butylamine complex in the presence of 1,3-bis(diphenylphosphino)propane. Electrospray ionization was used to introduce the clusters into the gas-phase and mass-selection was employed to isolate a single ionic cluster species (Au11L53+, L = 1,3-bis(diphenylphosphino)propane) which was delivered to surfaces at well controlled kinetic energies. Using in-situ time of flight secondary ion mass spectrometry (TOF-SIMS) it is demonstrated that the Au11L53+ cluster retains its 3+ charge state when soft landed onto the surface of a 1H,1H,2H,2H-

  13. Stable isotope, site-specific mass tagging for protein identification

    DOE Patents [OSTI]

    Chen, Xian

    2006-10-24

    Proteolytic peptide mass mapping as measured by mass spectrometry provides an important method for the identification of proteins, which are usually identified by matching the measured and calculated m/z values of the proteolytic peptides. A unique identification is, however, heavily dependent upon the mass accuracy and sequence coverage of the fragment ions generated by peptide ionization. The present invention describes a method for increasing the specificity, accuracy and efficiency of the assignments of particular proteolytic peptides and consequent protein identification, by the incorporation of selected amino acid residue(s) enriched with stable isotope(s) into the protein sequence without the need for ultrahigh instrumental accuracy. Selected amino acid(s) are labeled with .sup.13C/.sup.15N/.sup.2H and incorporated into proteins in a sequence-specific manner during cell culturing. Each of these labeled amino acids carries a defined mass change encoded in its monoisotopic distribution pattern. Through their characteristic patterns, the peptides with mass tag(s) can then be readily distinguished from other peptides in mass spectra. The present method of identifying unique proteins can also be extended to protein complexes and will significantly increase data search specificity, efficiency and accuracy for protein identifications.

  14. Alkali ionization detector

    DOE Patents [OSTI]

    Hrizo, John (Monroeville, PA); Bauerle, James E. (Plum Borough, PA); Witkowski, Robert E. (West Mifflin, PA)

    1982-01-01

    A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

  15. Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

    2016-02-11

    In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS2) and allows performing action spectroscopy. Electron impact MS2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS2 and single ionization energy dependencemore » spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

  16. Spatially-Resolved Analysis of Glycolipids and Metabolites in Living Synechococcus sp. PCC7002 Using Nanospray Desorption Electrospray Ionization

    SciTech Connect (OSTI)

    Lanekoff, Ingela T.; Geydebrekht, Oleg V.; Pinchuk, Grigoriy E.; Konopka, Allan; Laskin, Julia

    2013-04-07

    Microorganisms release a diversity of organic compounds that couple interspecies metabolism, enable communication, or provide benefits to other microbes. Increased knowledge of microbial metabolite production will contribute to understanding of the dynamic microbial world and can potentially lead to new developments in drug discovery, biofuel production, and clinical research. Nanospray desorption electrospray ionization (nano-DESI) is an ambient ionization technique that enables detailed chemical characterization of molecules from a specific location on a surface without special sample pretreatment. Due to its ambient nature, living bacterial colonies growing on agar plates can be rapidly and non-destructively analyzed. We performed spatially resolved nano-DESI analysis of living Synechococcus sp. PCC 7002 colonies on agar plates. We use high resolution mass spectrometry and MS/MS analysis of the living Synechococcus sp. PCC 7002 colonies to detect metabolites and lipids, and confirm their identities. We found that despite the high salt content of the agar (osmolarity ca. 700 mM), nano-DESI analysis enables detailed characterization of metabolites produced by the colony. Using this technique, we identified several glycolipids found on the living colonies and examined the effect of the age of the colony on the chemical gradient of glucosylglycerol secreted onto agar.

  17. Improvements to Laser Ablation-Inductively Coupled Plasma-Mass...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Improvements to Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry for Quantitative Analysis using Short Pulse UV Laser FWPProject Description: Laser ablation inductively ...

  18. Ionizing radiation detector

    DOE Patents [OSTI]

    Thacker, Louis H.

    1990-01-01

    An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

  19. Amorphous silicon ionizing particle detectors

    DOE Patents [OSTI]

    Street, R.A.; Mendez, V.P.; Kaplan, S.N.

    1988-11-15

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation. 15 figs.

  20. Amorphous silicon ionizing particle detectors

    DOE Patents [OSTI]

    Street, Robert A.; Mendez, Victor P.; Kaplan, Selig N.

    1988-01-01

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation.

  1. Ionization detection system for aerosols

    DOE Patents [OSTI]

    Jacobs, Martin E.

    1977-01-01

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system utilizes a measuring ionization chamber which is modified to minimize false alarms and reductions in sensitivity resulting from changes in ambient temperature. In the preferred form of the modification, an annular radiation shield is mounted about the usual radiation source provided to effect ionization in the measuring chamber. The shield is supported by a bimetallic strip which flexes in response to changes in ambient temperature, moving the shield relative to the source so as to vary the radiative area of the source in a manner offsetting temperature-induced variations in the sensitivity of the chamber.

  2. Microscopic Evaluation of Contaminants in Ultra-High Purity Copper...

    Office of Scientific and Technical Information (OSTI)

    methods including scanning electron microscopy (SEM), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and secondary ionization mass spectrometry (SIMS). ...

  3. Nanopost Arrays Anchor Molecules, Improve Ion Yields for Laser...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    molecules by laser mass spectrometry: A matrix of nanoposts protects the biomolecule from beam damage and facilitates the vaporization and ionization needed in mass spectrometry. ...

  4. High pressure xenon ionization detector

    DOE Patents [OSTI]

    Markey, J.K.

    1989-11-14

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

  5. High pressure xenon ionization detector

    DOE Patents [OSTI]

    Markey, John K. (New Haven, CT)

    1989-01-01

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

  6. High resolution FT-ICR mass spectral analysis of bio-oil and residual water soluble organics produced by hydrothermal liquefaction of the marine microalga Nannochloropsis salina

    SciTech Connect (OSTI)

    Sudasinghe, Nilusha; Dungan, Barry; Lammers, Peter; Albrecht, Karl O.; Elliott, Douglas C.; Hallen, Richard T.; Schaub, Tanner

    2014-03-01

    We report a detailed compositional characterization of a bio-crude oil and aqueous by-product from hydrothermal liquefaction of Nannochloropsis salina by direct infusion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) in both positive- and negative-ionization modes. The FT-ICR MS instrumentation approach facilitates direct assignment of elemental composition to >7000 resolved mass spectral peaks and three-dimensional mass spectral images for individual heteroatom classes highlight compositional diversity of the two samples and provide a baseline description of these materials. Aromatic nitrogen compounds and free fatty acids are predominant species observed in both the bio-oil and aqueous fraction. Residual organic compounds present in the aqueous fraction show distributions that are slightly lower in both molecular ring and/or double bond value and carbon number relative to those found in the bio-oil, albeit with a high degree of commonality between the two compositions.

  7. Optical ionization detector

    DOE Patents [OSTI]

    Wuest, Craig R.; Lowry, Mark E.

    1994-01-01

    An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium.

  8. Optical ionization detector

    DOE Patents [OSTI]

    Wuest, C.R.; Lowry, M.E.

    1994-03-29

    An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium. 3 figures.

  9. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  10. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  11. Welding arc gap ionization device

    DOE Patents [OSTI]

    Schweikhardt, George M.

    1976-01-01

    An alpha emitting isotope is positioned near the tip of a TIG welding electrode so that the alpha radiation can provide an ionized path between the electrode and the workpiece.

  12. Resonance ionization for analytical spectroscopy

    DOE Patents [OSTI]

    Hurst, George S.; Payne, Marvin G.; Wagner, Edward B.

    1976-01-01

    This invention relates to a method for the sensitive and selective analysis of an atomic or molecular component of a gas. According to this method, the desired neutral component is ionized by one or more resonance photon absorptions, and the resultant ions are measured in a sensitive counter. Numerous energy pathways are described for accomplishing the ionization including the use of one or two tunable pulsed dye lasers.

  13. NREL: Measurements and Characterization - Dynamic Secondary Ion Mass

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectrometry Dynamic Secondary Ion Mass Spectrometry SIMS Depth profile SIMS depth profiles of hydrogen for a series of a-Si films undergoing solid-phase recrystallization at different temperatures. Hydrogen loss is greater for higher temperatures; however, the rate of loss for a given temperature is also affected by the type of dopant and proximity to the surface. Dynamic Secondary Ion Mass Spectrometry (SIMS) uses a continuous, focused beam of primary ions to remove material from the

  14. Lesson 4 - Ionizing Radiation | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 - Ionizing Radiation Lesson 4 - Ionizing Radiation Lesson Three showed that unstable isotopes emit energy as they become more stable. This energy is known as radiation. This lesson explores forms of radiation, where radiation is found, how we detect and measure radiation, what sources of radiation people are exposed to, whether radiation is harmful, and how we can limit our exposure. Specific topics covered in this lesson include: Types of radiation Non-ionizing Ionizing Forms of ionizing

  15. Continuous time-of-flight ion mass spectrometer

    DOE Patents [OSTI]

    Funsten, Herbert O.; Feldman, William C.

    2004-10-19

    A continuous time-of-flight mass spectrometer having an evacuated enclosure with means for generating an electric field located in the evacuated enclosure and means for injecting a sample material into the electric field. A source of continuous ionizing radiation injects ionizing radiation into the electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between arrival of a secondary electron out of said ionized atoms or molecules at a first predetermined location and arrival of a sample ion out of said ionized atoms or molecules at a second predetermined location.

  16. Linear electric field time-of-flight ion mass spectrometer

    DOE Patents [OSTI]

    Funsten, Herbert O.; Feldman, William C.

    2008-06-10

    A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

  17. Mass spectroscopic apparatus and method

    DOE Patents [OSTI]

    Bomse, David S.; Silver, Joel A.; Stanton, Alan C.

    1991-01-01

    The disclosure is directed to a method and apparatus for ionization modulated mass spectrometric analysis. Analog or digital data acquisition and processing can be used. Ions from a time variant source are detected and quantified. The quantified ion output is analyzed using a computer to provide a two-dimensional representation of at least one component present within an analyte.

  18. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, M. J.; Zoerb, M. C.; Campbell, N. R.; Zimmermann, K. J.; Blomquist, B. W.; Huebert, B. J.; Bertram, T. H.

    2015-10-01

    Benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e. DMS, ?-caryophyllene) as well as previously studied VOCs (i.e., isoprene, ?-pinene). Using a field deployable chemical ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt?1) to DMS, isoprene, and ?-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a weaker electric field, demonstrated that ion-molecule reactions likely proceed through amorecombination of ligand-switching and direct charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (R2=0.80) over a wide range of sampling conditions.less

  19. SIEMENS ADVANCED QUANTRA FTICR MASS SPECTROMETER FOR ULTRA HIGH RESOLUTION AT LOW MASS

    SciTech Connect (OSTI)

    Spencer, W; Laura Tovo, L

    2008-07-08

    . Analysis of low concentration ions, at the ppm level, required a separate analysis using ion ejection techniques. Chemical ionization due to the formation of the MH{sup +} ion or MD{sup +} increased the complexity of the spectra compared to magnetic sector mass spectra and formation of the protonated or deuterated complex was a dynamic function of the trap ion concentration. This made quantitative measurement more of a challenge. However, the resolution of the instrument was far superior to any other mass spectrometry technique that has been applied to the analysis of the hydrogen isotopes. The piezo-electric picoliter injection device offers a new way of submitting small quantities of atmospheric pressure sample gas for analysis. The new software had many improvements over the previous version but significant flaws in the beta codes remain that make the prototype units less than ideal. The instrument is a promising new technology that experience will likely improve. Unfortunately, Siemens has concluded that the technology will not be a commercial success and has decided to stop producing this product.

  20. Preparation and in situ Characterization of Surfaces Using Soft-Landing in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    SciTech Connect (OSTI)

    Alvarez, Jormarie; Cooks, Robert G.; Barlow, Stephan E.; Gaspar, Dan J.; Futrell, Jean H.; Laskin, Julia

    2005-06-01

    Mass-selected peptide ions produced by electrospray ionization were deposited onto fluorinated self-assembled monolayer surfaces (FSAM) surfaces by soft-landing using a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially designed for studying interactions of large ions with surfaces. Analysis of the modified surface was performed in situ by combining 2 keV Cs+ secondary ion mass spectrometry with FT-ICR detection of the sputtered ions (FT-ICR-SIMS). Regardless of the initial charge state of the precursor ion, the SIMS mass spectra included singly-protonated peptide fragment ions and peaks characteristic of the surfaces in all cases. In some experiments multiply-protonated peptide ions and [M+Au]+ ions were also observed upon SIMS analysis of modified surfaces. For comparison with the in situ analysis of the modified surfaces, ex situ analysis of some of the modified surfaces was performed by 25 kV Ga+ time of flight ? secondary ion mass spectrometry (ToF-SIMS). The ex situ analysis demonstrated that a significant number of soft-landed peptide ions remain charged on the surface even when exposed to air for several hours after deposition. Charge retention of soft-landed ions dramatically increases the ion yields obtained during SIMS analysis very sensitive detection of deposited material at less than 1% of monolayer coverage. Accumulation of charged species on the surface undergoes saturation due to Coulomb repulsion between charges at close to 30% coverage. We estimated that close to 1 ng of peptide could be deposited on the spot area of 4 mm2 of the FSAM surface without reaching saturation.

  1. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, Michelle J.; Zoerb, Matthew C.; Campbell, Nicole R.; Zimmermann, Kathryn J.; Blomquist, Byron W.; Huebert, Barry J.; Bertram, Timothy H.

    2016-04-05

    Here, benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e., DMS, β-caryophyllene) as well as previously studied VOCs (i.e., isoprene, α-pinene). Using a field deployable chemical-ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt−1) to DMS, isoprene, and α-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a much weaker electric field, demonstrated that ion–molecule reactions likely proceed through a combinationmore » of ligand-switching and direct charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (< 25 %) was observed for the detection of β-caryophyllene, a bicyclic sesquiterpene. The in-field stability of benzene cluster cations using CI-ToFMS was examined in the marine boundary layer during the High Wind Gas Exchange Study (HiWinGS). The use of benzene cluster cation chemistry for the selective detection of DMS was validated against an atmospheric pressure ionization mass spectrometer, where measurements from the two instruments were highly correlated (R2 > 0.95, 10 s averages) over a wide range of sampling conditions.« less

  2. Identification of a Previously Unobserved Dissociative Ionization...

    Office of Scientific and Technical Information (OSTI)

    Identification of a Previously Unobserved Dissociative Ionization Pathway in Time-Resolved Photospectroscopy of the Deuterium Molecule Not Available Temp HTML Storage 2: Cao, Wei; ...

  3. Ionization probes of molecular structure and chemistry

    SciTech Connect (OSTI)

    Johnson, P.M.

    1993-12-01

    Various photoionization processes provide very sensitive probes for the detection and understanding of the spectra of molecules relevant to combustion processes. The detection of ionization can be selective by using resonant multiphoton ionization or by exploiting the fact that different molecules have different sets of ionization potentials. Therefore, the structure and dynamics of individual molecules can be studied even in a mixed sample. The authors are continuing to develop methods for the selective spectroscopic detection of molecules by ionization, and to use these methods for the study of some molecules of combustion interest.

  4. The Cryogenic Dark Matter Search: First 5-Tower Data and Improved Understanding of Ionization Collection

    SciTech Connect (OSTI)

    Bailey, Catherine N.

    2010-01-01

    The Cryogenic Dark Matter Search (CDMS) is searching for Weakly Interacting Massive Particles (WIMPs) with cryogenic particle detectors. These detectors have the ability to discriminate between nuclear recoil candidate and electron recoil background events by collecting both phonon and ionization energy from recoils in the detector crystals. The CDMS-II experiment has completed analysis of the first data runs with 30 semiconductor detectors at the Soudan Underground Laboratory, resulting in a world leading WIMP-nucleon spin-independent cross section limit for WIMP masses above 44 GeV/c{sup 2}. As CDMS aims to achieve greater WIMP sensitivity, it is necessary to increase the detector mass and discrimination between signal and background events. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are surface and bulk trapping. Recent work has been focused on reducing surface trapping through the modification of fabrication methods for future detectors. Analyzing data taken with test devices has shown that hydrogen passivation of the amorphous silicon blocking layer worsens surface trapping. Additional data has shown that the iron-ion implantation used to lower the critical temperature of the tungsten transition-edge sensors causes a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and in situ at the experimental site have provided methods to optimize the neutralization process and monitor running conditions to maintain full ionization collection. This work details my contribution to the 5-tower data taking, monitoring, and analysis effort as well

  5. Improving the Sensitivity of Mass Spectrometry by Using a New...

    Office of Scientific and Technical Information (OSTI)

    Kelly, Ryan T. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Richard D. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); ...

  6. Open MSI : a Mass Spectrometry Imaging Science Gateway

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Gateway NERSC OSF Room 238 April 11, 2013 Ben Bowen Berkeley Lab Metabolite and protein analysis is vital to understanding the phenotype of a biological sample....

  7. Monitoring Trace Radionuclides by ICP Mass Spectrometry with...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    such measurements (from hours to several minutes), while maintaining at least reasonable accuracy (agreement with true ratios +- 3% or better) and precision (1% RSD or better),...

  8. Mass spectrometry of nuclear materials; Attention to detail

    SciTech Connect (OSTI)

    Shields, W.R

    1989-11-01

    Measurements of the {sup 235}U/{sup 238}U ratio in product-quality material have improved from uncertainties of 0.1 percent (rel) to 0.2 percent since the Manhattan Project. The hardware and procedural changes responsible for these measurement improvements are traced and discussed.

  9. A new detector for mass spectrometry: Direct detection of low...

    Office of Scientific and Technical Information (OSTI)

    Resource Relation: Journal Name: Review of Scientific Instruments; Journal Volume: 83; Journal Issue: 1; Other Information: (c) 2012 American Institute of Physics; Country of ...

  10. Ionization tube simmer current circuit

    DOE Patents [OSTI]

    Steinkraus, R.F. Jr.

    1994-12-13

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

  11. Ionization tube simmer current circuit

    DOE Patents [OSTI]

    Steinkraus, Jr., Robert F.

    1994-01-01

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

  12. Evolution of extreme resistance to ionizing radiation via genetic...

    Office of Scientific and Technical Information (OSTI)

    Published Article: Evolution of extreme resistance to ionizing radiation via genetic adaptation of DNA repair Prev Next Title: Evolution of extreme resistance to ionizing ...

  13. Final Report: Ionization chemistry of high temperature molecular...

    Office of Scientific and Technical Information (OSTI)

    Final Report: Ionization chemistry of high temperature molecular fluids Citation Details In-Document Search Title: Final Report: Ionization chemistry of high temperature molecular ...

  14. Laser Ionized Preformed Plasma at FACET (Conference) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Conference: Laser Ionized Preformed Plasma at FACET Citation Details In-Document Search Title: Laser Ionized Preformed Plasma at FACET You are accessing a document from the ...

  15. Communication: Transfer ionization in a thermal reaction of a cation and anion: Ar{sup +} with Br{sup −} and I{sup −}

    SciTech Connect (OSTI)

    Shuman, Nicholas S.; Miller, Thomas M.; Viggiano, Albert A.; Johnsen, Rainer

    2013-11-07

    We present experimental evidence that reactions of argon cations Ar{sup +} with the halogen anions Br{sup −} and I{sup −} do not occur exclusively by mutual neutralization, but also produce the cations Br{sup +} or I{sup +} ions by transfer ionization (TI). The experiments were carried out in flowing-afterglow plasmas at gas temperatures between and 300 and 500 K, and employed a variant of the Variable Electron and Neutral Density Attachment Mass Spectrometry method. The measured TI rate coefficients are 1.9 ± 0.6 × 10{sup −9} cm{sup 3} s{sup −1} and 1.1 ± {sub 0.3}{sup 0.8}× 10{sup −9} cm{sup 3} s{sup −1} for the Br{sup −} and I{sup −} reactions, respectively. We find that the TI rate coefficients decline with temperature as T{sup −0.5} to T{sup −1}. No indication of TI was found in the reaction with Cl{sup −}, where it is endoergic.

  16. Ruthenium trisbipyridine as a candidate for gas-phase spectroscopic studies in a Fourier transform mass spectrometer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Scott, Jill R.; Ham, Jason E.; Durham, Bill; Tremblay, Paul L.

    2004-01-01

    Metal polypyridines are excellent candidates for gas-phase optical experiments where their intrinsic properties can be studied without complications due to the presence of solvent. The fluorescence lifetimes of [Ru(bpy) 3 ] 1+ trapped in an optical detection cell within a Fourier transform mass spectrometer were obtained using matrix-assisted laser desorption/ionization to generate the ions with either 2,5-dihydroxybenzoic acid (DHB) or sinapinic acid (SA) as matrix. All transients acquired, whether using DHB or SA for ion generation, were best described as approximately exponential decays. The rate constant for transients derived using DHB as matrix was 4×10 7 s −1 ,more » while the rate constant using SA was 1×10 7 s −1 . Some suggestions of multiple exponential decay were evident although limited by the quality of the signals. Photodissociation experiments revealed that [Ru(bpy) 3 ] 1+ generated using DHB can decompose to [Ru(bpy) 2 ] 1+ , whereas ions generated using SA showed no decomposition. Comparison of the mass spectra with the fluorescence lifetimes illustrates the promise of incorporating optical detection with trapped ion mass spectrometry techniques.« less

  17. (Resonance ionization spectroscopy and its applications)

    SciTech Connect (OSTI)

    Ramsey, J.M.

    1990-10-11

    The Fifth International Symposium in Resonance Ionization Spectroscopy and Its Applications was attended. The Joint Research Centre of the European Communities at Ispra, Italy was also visited. The traveler presented an invited talk, chaired a meeting session and gave an impromptu presentation on how current laser technology limits the development of commercial instrumentation based upon Resonance Ionization Spectroscopy. The conference was truely international with scientists from 19 countries and less than 1/4 from the US. The meeting also provided a health mixture of experimentalists and theoreticians. Technical developments reported included the use of electric field ionization from laser prepared Rydberg states as a way to reduce background signals and commercial development of an optical parametric oscillator for replacing pulsed dye laser. A speaker from the Soviet Union suggested their willingness to market hardware they have developed based upon the resonance ionization technique.

  18. Gas amplified ionization detector for gas chromatography

    DOE Patents [OSTI]

    Huston, Gregg C.

    1992-01-01

    A gas-amplified ionization detector for gas chromatrography which possesses increased sensitivity and a very fast response time. Solutes eluding from a gas chromatographic column are ionized by UV photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the UV photoionization of at least a portion of each solute passing through the detector.

  19. GAS IONIZING AND COMPRESSING DEVICE

    DOE Patents [OSTI]

    Little, E.M.; Thomson, D.B.; Josephson, V.; Scott, F.R.

    1961-08-22

    A device is described for producing high energy gaseous plasmas. The device consists of a unitary refractory vessel having tapered end portions, a cylindrical middle portion, and means for spontaneously generating oppositely propelled plasma masses from the tapered end portions to a collision zone in the cylindrical middle portion. The means come from the spontaneous generation of diverging magnetic fields in the end portions and an axial magnetic field in the cylindrical portion. (AEC)

  20. MASS SPECTROMETER

    DOE Patents [OSTI]

    White, F.A.

    1960-08-23

    A mass spectrometer is designed with a first adjustable magnetic field for resolving an ion beam into beams of selected masses, a second adjustable magnetic field for further resolving the ion beam from the first field into beams of selected masses, a thin foil disposed in the path of the beam between the first and second magnets to dissociate molecular ions incident thereon, an electrostatic field for further resolving the ion beam from the second field into beams of selected masses, and a detector disposed adjacent to the electrostatic field to receive the ion beam.

  1. Highly ionized physical vapor deposition plasma source working at very low pressure

    SciTech Connect (OSTI)

    Stranak, V.; Herrendorf, A.-P.; Drache, S.; Hippler, R.; Cada, M.; Hubicka, Z.; Tichy, M.

    2012-04-02

    Highly ionized discharge for physical vapor deposition at very low pressure is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of pressure during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical pressure ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti{sup +} and Ti{sup ++} peaks are observed in the mass scan spectra). This corresponds well with high plasma density n{sub e} {approx} 10{sup 18} m{sup -3}, measured during the HiPIMS pulse.

  2. Formation of ketene (H{sub 2}CCO) in interstellar analogous methane (CH{sub 4})-carbon monoxide (CO) ices: A combined FTIR and reflectron time-of-flight mass spectroscopic study

    SciTech Connect (OSTI)

    Maity, Surajit; Kaiser, Ralf I.; Jones, Brant M.

    2014-07-01

    The formation of ketene (H{sub 2}CCO) in methane-carbon monoxide (CH{sub 4}-CO) ices was investigated upon its exposure to ionizing radiation in the form of energetic electrons at 5.5 K. The radiation-induced nonthermal equilibrium processing of these ices was monitored online and in situ via infrared spectroscopy complimented with post-irradiation temperature programmed desorption studies exploiting highly sensitive reflectron time-of-flight mass spectrometry (ReTOF) coupled with single photon fragment-free photo ionization (PI) at 10.49 eV. The detection of ketene in irradiated (isotopically labeled) methane-carbon monoxide ices was confirmed via the ?{sub 2} infrared absorption band and substantiated during the warm-up phase based on sublimation profiles obtained from the ReTOF-PI spectra of the corresponding isotopic masses. The experiments conducted with the mixed isotopic ices of {sup 12}CD{sub 4}-{sup 13}CO provide clear evidence of the formation of at least two ketene isotopomers (D{sub 2} {sup 12}C{sup 13}CO and D{sub 2} {sup 13}C{sup 13}CO), allowing for the derivation of two competing formation pathways. We have also proposed underlying reaction mechanisms to the formation of ketene based on kinetic fitting of the temporal evolution of the ketene isotopomers.

  3. The Cryogenic Dark Matter Search low ionization-threshold experiment

    SciTech Connect (OSTI)

    Basu Thakur, Ritoban

    2014-01-01

    Over 80 years ago we discovered the presence of Dark Matter in our universe. Endeavors in astronomy and cosmology are in consensus with ever improving precision that Dark Matter constitutes an essential 27% of our universe. The Standard Model of Particle Physics does not provide any answers to the Dark Matter problem. It is imperative that we understand Dark Matter and discover its fundamental nature. This is because, alongside other important factors, Dark Matter is responsible for formation of structure in our universe. The very construct in which we sit is defined by its abundance. The Milky Way galaxy, hence life, wouldn't have formed if small over densities of Dark Matter had not caused sufficient accretion of stellar material. Marvelous experiments have been designed based on basic notions to directly and in-directly study Dark Matter, and the Cryogenic Dark Matter Search (CDMS) experiment has been a pioneer and forerunner in the direct detection field. Generations of the CDMS experiment were designed with advanced scientific upgrades to detect Dark Matter particles of mass O(100) GeV/c2. This mass-scale was set primarily by predictions from Super Symmetry. Around 2013 the canonical SUSY predictions were losing some ground and several observations (rather hints of signals) from various experiments indicated to the possibility of lighter Dark Matter of mass O(10) GeV/c2. While the SuperCDMS experiment was probing the regular parameter space, the CDMSlite experiment was conceived to dedicatedly search for light Dark Matter using a novel technology. "CDMSlite" stands for CDMS - low ionization threshold experiment. Here we utilize a unique electron phonon coupling mechanism to measure ionization generated by scattering of light particles. Typically signals from such low energy recoils would be washed under instrumental noise. In CDMSlite via generation of Luke-Neganov phonons we can detect the small ionization energies, amplified in phonon

  4. Advanced Mass Spectrometric Methods for the Rapid and Quantitative Characterization of Proteomes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Smith, Richard D.

    2002-01-01

    Progress is reviewedmore » towards the development of a global strategy that aims to extend the sensitivity, dynamic range, comprehensiveness and throughput of proteomic measurements based upon the use of high performance separations and mass spectrometry. The approach uses high accuracy mass measurements from Fourier transform ion cyclotron resonance mass spectrometry (FTICR) to validate peptide ‘accurate mass tags’ (AMTs) produced by global protein enzymatic digestions for a specific organism, tissue or cell type from ‘potential mass tags’ tentatively identified using conventional tandem mass spectrometry (MS/MS). This provides the basis for subsequent measurements without the need for MS/ MS. High resolution capillary liquid chromatography separations combined with high sensitivity, and high resolution accurate FTICR measurements are shown to be capable of characterizing peptide mixtures of more than 10 5 components. The strategy has been initially demonstrated using the microorganisms Saccharomyces cerevisiae and Deinococcus radiodurans. Advantages of the approach include the high confidence of protein identification, its broad proteome coverage, high sensitivity, and the capability for stableisotope labeling methods for precise relative protein abundance measurements. Abbreviations : LC, liquid chromatography; FTICR, Fourier transform ion cyclotron resonance; AMT, accurate mass tag; PMT, potential mass tag; MMA, mass measurement accuracy; MS, mass spectrometry; MS/MS, tandem mass spectrometry; ppm, parts per million.« less

  5. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, Michelle J.; Zoerb, Matthew C.; Campbell, Nicole R.; Zimmermann, Kathryn J.; Blomquist, Byron W.; Huebert, Barry J.; Bertram, Timothy H.

    2016-01-01

    Benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e., DMS, β-caryophyllene) as well as previously studied VOCs (i.e., isoprene, α-pinene). Using a field deployable chemical-ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt−1) to DMS, isoprene, and α-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a much weaker electric field, demonstrated that ion–molecule reactions likely proceed through a combination of ligand-switching and directmore » charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (< 25 %) was observed for the detection of β-caryophyllene, a bicyclic sesquiterpene. The in-field stability of benzene cluster cations using CI-ToFMS was examined in the marine boundary layer during the High Wind Gas Exchange Study (HiWinGS). The use of benzene cluster cation chemistry for the selective detection of DMS was validated against an atmospheric pressure ionization mass spectrometer, where measurements from the two instruments were highly correlated (R2 > 0.95, 10 s averages) over a wide range of sampling conditions.« less

  6. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    SciTech Connect (OSTI)

    University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center; Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

    2011-07-19

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

  7. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    SciTech Connect (OSTI)

    University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; L.Vaghjiani, Ghanshyam; Leone, Stephen R.

    2012-03-16

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1- Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

  8. Memory in Nonlinear Ionization of Transparent Solids

    SciTech Connect (OSTI)

    Rajeev, P. P.; Simova, E.; Hnatovsky, C.; Taylor, R. S.; Rayner, D. M.; Corkum, P. B.; Gertsvolf, M.; Bhardwaj, V. R.

    2006-12-22

    We demonstrate a shot-to-shot reduction in the threshold laser intensity for ionization of bulk glasses illuminated by intense femtosecond pulses. For SiO{sub 2} the threshold change serves as positive feedback reenforcing the process that produced it. This constitutes a memory in nonlinear ionization of the material. The threshold change saturates with the number of pulses incident at a given spot. Irrespective of the pulse energy, the magnitude of the saturated threshold change is constant ({approx}20%). However, the number of shots required to reach saturation does depend on the pulse energy. Recognition of a memory in ionization is vital to understand multishot optical or electrical breakdown phenomena in dielectrics.

  9. Resonance ionization spectroscopy of zirconium atoms

    SciTech Connect (OSTI)

    Page, R.H.; Dropinski, S.C.; Worden, E.F. Jr.; Stockdale, J.A.D.

    1992-05-01

    We have examined the stepwise-resonant three-photon-ionization spectrum of neutral zirconium atoms using three separately-tunable pulsed visible dye lasers. Lifetimes of even-parity levels (measured with delayed-photoionization technique) range from 10 to 100 nsec. Direct ionization cross sections appear to be less than 10{sup {minus}17} cm{sup 2}; newly-detected autoionizing levels give peak ionization cross sections (inferred from saturation fluences) up to 10{sup {minus}15} cm{sup 2}. Members of Rydberg series converging to the 315 and 1323 cm{sup {minus}1} levels of Zr{sup +} were identified. ``Clumps`` of autoionizing levels are thought to be due to Rydberg-valence mixing.

  10. Ionization-chamber smoke detector system

    DOE Patents [OSTI]

    Roe, Robert F.

    1976-10-19

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

  11. Above-threshold ionization beyond the dipole approximation

    SciTech Connect (OSTI)

    Klaiber, Michael; Hatsagortsyan, Karen Z.; Keitel, Christoph H.

    2005-03-01

    A generalization of the analytical theory of above-threshold ionization in the single active electron approximation is developed while taking into account leading non-dipole and relativistic corrections in the starting Hamiltonian. Special interest is placed on the high energy part of the photoelectron spectrum which consists of a plateau and a characteristic cutoff. It is shown that the correction due to the magnetic component of the laser field gives rise to a decrease of the plateau height, an increase of the maximal cutoff energy, and a drift of the emitted electrons in propagation direction of the laser field. Furthermore, the influence of the relativistic mass shift may become non-neglible by reducing the cutoff energy significantly. Spin effects or the Zitterbewegung play a comparably minor role in the investigated parameter regime of suboptical frequencies and high but not ultra-high laser intensities.

  12. Ionized cluster beam technology for material science

    SciTech Connect (OSTI)

    Takagi, Toshinori

    1997-06-20

    The most suitable kinetic energy range of ionized materials in film formation and epitaxial growth is from a few eV to a few hundreds eV, especially, less than about 100eV, when ions are used as a host. The main roles of ions in film formation are the effects due to their kinetic energy and the electronic charge effects which involve the effect to active film formation and the effect acceleration of chemical reactions. Therefore, it is important to develope the technology to transport large volume of a flux of ionized particles with an extremely low incident energy without any troubles due to the space charge effects and charge up problems on the surface. This is the exact motivation for us to have been developing the Ionized Cluster Beam (ICB) technology since 1972. By ICB technology materials (actually wide varieties of materials such as metal, semiconductor, magnetic material, insulator, organic material, etc.) are vaporized and ejected through a small hole nozzle into a high vacuum, where the vaporized material condenses into clusters with loosely coupled atoms with the sizes about from 100 to a few 1000 atoms (mainly 100-2000 atoms) by supercondensation phenomena due to the adiabatic expansion in this evaporation process through a small hole nozzle. In the ICB technology an atom in each cluster is ionized by irradiated by electron shower, and the ionized clusters are accelerated by electric field onto a substrate. The ionized clusters with neutral clusters impinged onto a substrate are spreaded separately into atoms migrating over the substrate, so that the surface migration energy of the impinged atoms, that is, surface diffusion energy are controlled by an incident energy of a cluster. In this report the theoretical and also experimental results of ICB technology are summarized.

  13. Improving Alpha Spectrometry Energy Resolution by Ion Implantation with ICP-MS

    SciTech Connect (OSTI)

    Dion, Michael P.; Liezers, Martin; Farmer, Orville T.; Miller, Brian W.; Morley, Shannon M.; Barinaga, Charles J.; Eiden, Gregory C.

    2015-01-01

    We report results of a novel technique using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) as a method of source preparation for alpha spectrometry. This method produced thin, contaminant free 241Am samples which yielded extraordinary energy resolution which appear to be at the lower limit of the detection technology used in this research.

  14. Time-of-flight heavy ion backscattering spectrometry

    SciTech Connect (OSTI)

    Knapp, J.A.; Banks, J.C.; Doyle, B.L.

    1993-08-01

    A new time-of-flight (TOF) ion detection system for Heavy Ion Backscattering Spectrometry (HIBS) is described. Examples are also given of the use of the system for measuring low-level contamination on Si wafers. Currently, the TOF-HBIS system has a sensitivity of 1 {times} 10{sup 9}/cm{sup 2} for the heaviest of surface impurity atoms and a mass resolution capable of separating Fe from Cu. The sensitivity is expected to improve by an additional order of magnitude on a industrial TOF-HIBS system being constructed for SEMATECH.

  15. Neutron spectrometry for UF6 enrichment verification in storage cylinders

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mengesha, Wondwosen; Kiff, Scott D.

    2015-01-29

    Verification of declared UF6 enrichment and mass in storage cylinders is of great interest in nuclear material nonproliferation. Nondestructive assay (NDA) techniques are commonly used for safeguards inspections to ensure accountancy of declared nuclear materials. Common NDA techniques used include gamma-ray spectrometry and both passive and active neutron measurements. In the present study, neutron spectrometry was investigated for verification of UF6 enrichment in 30B storage cylinders based on an unattended and passive measurement approach. MCNP5 and Geant4 simulated neutron spectra, for selected UF6 enrichments and filling profiles, were used in the investigation. The simulated neutron spectra were analyzed using principalmore » component analysis (PCA). The PCA technique is a well-established technique and has a wide area of application including feature analysis, outlier detection, and gamma-ray spectral analysis. Results obtained demonstrate that neutron spectrometry supported by spectral feature analysis has potential for assaying UF6 enrichment in storage cylinders. The results from the present study also showed that difficulties associated with the UF6 filling profile and observed in other unattended passive neutron measurements can possibly be overcome using the approach presented.« less

  16. Atomic ionization by keV-scale pseudoscalar dark-matter particles

    SciTech Connect (OSTI)

    Dzuba, V. A.; Flambaum, V. V.; Pospelov, M.

    2010-05-15

    Using the relativistic Hartree-Fock approximation, we calculate the rates of atomic ionization by absorption of pseudoscalar particles in the mass range from 10 to {approx}50 keV. We present numerical results for atoms relevant for the direct dark-matter searches (e.g. Ar, Ge, I and Xe), as well as the analytical formula which fits numerical calculations with few per cent accuracy and may be used for multielectron atoms, molecules and condensed matter systems.

  17. Low pressure electrospray ionization system and process for effective transmission of ions

    DOE Patents [OSTI]

    Tang, Keqi; Page, Jason S.; Kelly, Ryan T.; Smith, Richard D.

    2010-03-02

    A system and method are disclosed that provide up to complete transmission of ions between coupled stages with low effective ion losses. A novel "interfaceless" electrospray ionization system is further described that operates the electrospray at a reduced pressure such that standard electrospray sample solutions can be directly sprayed into an electrodynamic ion funnel which provides ion focusing and transmission of ions into a mass analyzer.

  18. Low pressure electrospray ionization system and process for effective transmission of ions

    DOE Patents [OSTI]

    Tang, Keqi; Page, Jason S; Kelly, Ryan T; Smith, Richard D

    2012-05-08

    Systems and methods that provide up to complete transmission of ions between coupled stages with low effective ion losses. An "interfaceless" electrospray ionization system is further described that operates an electrospray at a reduced pressure such that standard electrospray sample solutions can be directly sprayed into an electrodynamic ion funnel which provides ion focusing and transmission of ions into a mass analyzer. Furthermore, chambers maintained at different pressures can allow for more optimal operating conditions for an electrospray emitter and an ion guide.

  19. Composite scintillators for detection of ionizing radiation

    DOE Patents [OSTI]

    Dai, Sheng [Knoxville, TN; Stephan, Andrew Curtis [Knoxville, TN; Brown, Suree S [Knoxville, TN; Wallace, Steven A [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

    2010-12-28

    Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

  20. WARPED IONIZED HYDROGEN IN THE GALAXY

    SciTech Connect (OSTI)

    Cersosimo, J. C.; Figueroa, N. Santiago; Velez, S. Figueroa; Soto, C. Lozada; Mader, S.; Azcarate, D.

    2009-07-01

    We report observations of the H166{alpha} ({nu} = 1424.734 MHz) radio recombination line (RRL) emission from the Galactic plane in the longitude range l = 267 deg. - 302 deg. and latitude range b = -3.{sup 0}0 to +1.{sup 0}5. The line emission observed describes the Carina arm in the Galactic azimuth range from {theta} = 260 deg. to 190 deg. The structure is located at negative latitudes with respect to the formal Galactic plane. The observations are combined with RRL data from the first Galactic quadrant. Both quadrants show the signature of the warp for the ionized gas, but an asymmetry of the distribution is noted. In the fourth quadrant, the gas is located between Galactic radii R {approx} 7 and 10 kpc, and the amplitude of the warp is seen from the midplane to z {approx} -150 pc. In the first quadrant, the gas is found between R {approx} 8 and 13-16 kpc, and flares to z {approx} +350 pc. We confirm the warp of the ionized gas near the solar circle. The distribution of the ionized gas is compared with the maximum intensity H I emission (0.30 < n{sub HI} < 0.45 cm{sup -3}) at intervals of the Galactic ring. The ionized material is correlated with the H I maximum intensity in both quadrants, and both components show the same tilted behavior with respect to the mid-Galactic plane.

  1. Theory of multiphoton ionization of atoms

    SciTech Connect (OSTI)

    Szoeke, A.

    1986-03-01

    A non-perturbative approach to the theory of multiphoton ionization is reviewed. Adiabatic Floquet theory is its first approximation. It explains qualitatively the energy and angular distribution of photoelectrons. In many-electron atoms it predicts collective and inner shell excitation. 14 refs.

  2. Capillary zone electrophoresis-mass spectrometer interface

    DOE Patents [OSTI]

    D`Silva, A.

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.

  3. Capillary zone electrophoresis-mass spectrometer interface

    DOE Patents [OSTI]

    D'Silva, Arthur

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.

  4. The MICE Demonstration of Ionization Cooling

    SciTech Connect (OSTI)

    Pasternak, J.; Blackmore, V.; Hunt, C.; Lagrange, J-B.; Long, K.; Collomb, N.; Snopok, P.

    2015-05-01

    Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions at energies of up to several TeV at the Muon Collider. The International Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization cooling channel, the muon beam passes through a material (the absorber) in which it loses energy. The energy lost is then replaced using RF cavities. The combined effect of energy loss and re-acceleration is to reduce the transverse emittance of the beam (transverse cooling). A major revision of the scope of the project was carried out over the summer of 2014. The revised project plan, which has received the formal endorsement of the international MICE Project Board and the international MICE Funding Agency Committee, will deliver a demonstration of ionization cooling by September 2017. In the revised configuration a central lithium-hydride absorber provides the cooling effect. The magnetic lattice is provided by the two superconducting focus coils and acceleration is provided by two 201 MHz single-cavity modules. The phase space of the muons entering and leaving the cooling cell will be measured by two solenoidal spectrometers. All the superconducting magnets for the ionization cooling demonstration are available at the Rutherford Appleton Laboratory and the first single-cavity prototype is under test in the MuCool Test Area at Fermilab. The design of the cooling demonstration experiment will be described together with a summary of the performance of each of its components. The cooling performance of the revised configuration will also be presented.

  5. Extending Penning trap mass measurements with SHIPTRAP to the heaviest elements

    SciTech Connect (OSTI)

    Block, M.; Ackermann, D.; Herfurth, F.; Hofmann, S.; Blaum, K.; Droese, C.; Marx, G.; Schweikhard, L.; Duellmann, Ch. E.; Eibach, M.; Eliseev, S.; Haettner, E.; Plass, W. R.; Scheidenberger, C.; Hessberger, F. P.; Ramirez, E. Minaya; Nesterenko, D.; and others

    2013-03-19

    Penning-trap mass spectrometry of radionuclides provides accurate mass values and absolute binding energies. Such mass measurements are sensitive indicators of the nuclear structure evolution far away from stability. Recently, direct mass measurements have been extended to the heavy elements nobelium (Z=102) and lawrencium (Z=103) with the Penning-trap mass spectrometer SHIPTRAP. The results probe nuclear shell effects at N=152. New developments will pave the way to access even heavier nuclides.

  6. A study of electron recombination using highly ionizing particles...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    7) Eliminate lightly ionizing ptcls by requiring T calo > 0.5 T range Collection Induction Time ADC Select Highly Ionizing Particles Wire time time ANT 2013 Baller 13 Particle...

  7. Understanding the anomalous dispersion of doubly-ionized carbon...

    Office of Scientific and Technical Information (OSTI)

    of doubly-ionized carbon plasmas near 47 nm Citation Details In-Document Search Title: Understanding the anomalous dispersion of doubly-ionized carbon plasmas near 47 nm Over ...

  8. EXTENDED ANALYSIS OF THE SPECTRUM OF SINGLY IONIZED CHROMIUM...

    Office of Scientific and Technical Information (OSTI)

    EXTENDED ANALYSIS OF THE SPECTRUM OF SINGLY IONIZED CHROMIUM (Cr II) Citation Details In-Document Search Title: EXTENDED ANALYSIS OF THE SPECTRUM OF SINGLY IONIZED CHROMIUM (Cr II) ...

  9. Quark Masses

    SciTech Connect (OSTI)

    Gasser, Juerg

    2005-10-26

    In my talk, I reviewed some basic aspects of quark masses: what do they mean, how can they be determined, what is our present knowledge on them. The talk was addressed to non specialists in the field, and so is this write up.

  10. Ionization source utilizing a multi-capillary inlet and method of operation

    DOE Patents [OSTI]

    Smith, Richard D.; Kim, Taeman; Udseth, Harold R.

    2004-10-12

    A multi-capillary inlet to focus ions and other charged particles generated at or near atmospheric pressure into a relatively low pressure region, which allows increased conductance of ions and other charged particles. The multi-capillary inlet is juxtaposed between an ion source and the interior of an instrument maintained at near atmospheric pressure, it finds particular advantages when deployed to improve the ion transmission between an electrospray ionization source and the first vacuum stage of a mass spectrometer, and finds its greatest advantages when deployed in conjunction with an electrodynamic (RF) ion funnel deployed within the interior of the mass spectrometer, particularly an ion funnel equipped with a jet disturber.

  11. Quantum Theory for Cold Avalanche Ionization in Solids

    SciTech Connect (OSTI)

    Deng, H. X.; Zu, X. T.; Xiang, X.; Sun, K.

    2010-09-10

    A theory of photon-assisted impact ionization in solids is presented. Our theory makes a quantum description of the new impact ionization--cold avalanche ionization recently reported by P. P. Rajeev, M. Gertsvolf, P. B. Corkum, and D. M. Rayner [Phys. Rev. Lett. 102, 083001 (2009)]. The present theory agrees with the experiments and can be reduced to the traditional impact ionization expression in the absence of a laser.

  12. Method and apparatus to monitor a beam of ionizing radiation

    SciTech Connect (OSTI)

    Blackburn, Brandon W.; Chichester, David L.; Watson, Scott M.; Johnson, James T.; Kinlaw, Mathew T.

    2015-06-02

    Methods and apparatus to capture images of fluorescence generated by ionizing radiation and determine a position of a beam of ionizing radiation generating the fluorescence from the captured images. In one embodiment, the fluorescence is the result of ionization and recombination of nitrogen in air.

  13. Closed-loop pulsed helium ionization detector

    DOE Patents [OSTI]

    Ramsey, Roswitha S.; Todd, Richard A.

    1987-01-01

    A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.

  14. Ionization photophysics and spectroscopy of cyanoacetylene

    SciTech Connect (OSTI)

    Leach, Sydney; Champion, Norbert; Garcia, Gustavo A.; Fray, Nicolas; Gaie-Levrel, François; Mahjoub, Ahmed; Bénilan, Yves; Gazeau, Marie-Claire; Schwell, Martin

    2014-05-07

    Photoionization of cyanoacetylene was studied using synchrotron radiation over the non-dissociative ionization excitation range 11–15.6 eV, with photoelectron-photoion coincidence techniques. The absolute ionization cross-section and spectroscopic aspects of the parent ion were recorded. The adiabatic ionization energy of cyanoacetylene was measured as 11.573 ± 0.010 eV. A detailed analysis of photoelectron spectra of HC{sub 3}N involves new aspects and new assignments of the vibrational components to excitation of the A{sup 2}Σ{sup +} and B{sup 2}Π states of the cation. Some of the structured autoionization features observed in the 11.94 to 15.5 eV region of the total ion yield (TIY) spectrum were assigned to two Rydberg series converging to the B{sup 2}Π state of HC{sub 3}N{sup +}. A number of the measured TIY features are suggested to be vibrational components of Rydberg series converging to the C{sup 2}Σ{sup +} state of HC{sub 3}N{sup +} at ≈17.6 eV and others to valence shell transitions of cyanoacetylene in the 11.6–15 eV region. The results of quantum chemical calculations of the cation electronic state geometries, vibrational frequencies and energies, as well as of the C–H dissociation potential energy profiles of the ground and electronic excited states of the ion, are compared with experimental observations. Ionization quantum yields are evaluated and discussed and the problem of adequate calibration of photoionization cross-sections is raised.

  15. Genetic variation in resistance to ionizing radiation

    SciTech Connect (OSTI)

    Ayala, F.J.

    1989-01-01

    The very reactive superoxide anion O[sub 2] is generated during cell respiration as well as during exposure to ionizing radiation. Organisms have evolved different mechanisms to protect against the deleterious effects of reduced oxygen species. The copper-zinc superoxide dismutase is a eukaryotic cytoplasmic enzyme that protects the cell by scavenging superoxide radicals and dismutating them to hydrogen peroxide and molecular oxygen: 20[sub 2][sup [minus

  16. Alloy nanoparticle synthesis using ionizing radiation

    DOE Patents [OSTI]

    Nenoff, Tina M.; Powers, Dana A.; Zhang, Zhenyuan

    2011-08-16

    A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

  17. RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES

    SciTech Connect (OSTI)

    Conroy, Charlie; Kratter, Kaitlin M.

    2012-08-20

    Approximately 30% of all massive stars in the Galaxy are runaways with velocities exceeding 30 km s{sup -1}. Their high speeds allow them to travel {approx}0.1-1 kpc away from their birthplace before they explode at the end of their several Myr lifetimes. At high redshift, when galaxies were much smaller than in the local universe, runaways could venture far from the dense inner regions of their host galaxies. From these large radii, and therefore low column densities, much of their ionizing radiation is able to escape into the intergalactic medium. Runaways may therefore significantly enhance the overall escape fraction of ionizing radiation, f{sub esc}, from small galaxies at high redshift. We present simple models of the high-redshift runaway population and its impact on f{sub esc} as a function of halo mass, size, and redshift. We find that the inclusion of runaways enhances f{sub esc} by factors of Almost-Equal-To 1.1-8, depending on halo mass, galaxy geometry, and the mechanism of runaway production, implying that runaways may contribute 50%-90% of the total ionizing radiation escaping from high-redshift galaxies. Runaways may therefore play an important role in reionizing the universe.

  18. Compact hydrogen/helium isotope mass spectrometer

    DOE Patents [OSTI]

    Funsten, Herbert O.; McComas, David J.; Scime, Earl E.

    1996-01-01

    The compact hydrogen and helium isotope mass spectrometer of the present invention combines low mass-resolution ion mass spectrometry and beam-foil interaction technology to unambiguously detect and quantify deuterium (D), tritium (T), hydrogen molecule (H.sub.2, HD, D.sub.2, HT, DT, and T.sub.2), .sup.3 He, and .sup.4 He concentrations and concentration variations. The spectrometer provides real-time, high sensitivity, and high accuracy measurements. Currently, no fieldable D or molecular speciation detectors exist. Furthermore, the present spectrometer has a significant advantage over traditional T detectors: no confusion of the measurements by other beta-emitters, and complete separation of atomic and molecular species of equivalent atomic mass (e.g., HD and .sup.3 He).

  19. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Plant, Idaho Falls, ID (United States) Idaho National Engineering Laboratory, Idaho Falls, ... Atmospheric Ionization Mass Spectrometry Capabilities at Sandia National Labs. ...

  20. Development of high-spatial and high-mass resolution mass spectrometric imaging (MSI) and its application to the study of small metabolites and endogenous molecules of plants

    SciTech Connect (OSTI)

    Jun, Ji Hyun

    2011-11-30

    High-spatial and high-mass resolution laser desorption ionization (LDI) mass spectrometric (MS) imaging technology was developed for the attainment of MS images of higher quality containing more information on the relevant cellular and molecular biology in unprecedented depth. The distribution of plant metabolites is asymmetric throughout the cells and tissues, and therefore the increase in the spatial resolution was pursued to reveal the localization of plant metabolites at the cellular level by MS imaging. For achieving high-spatial resolution, the laser beam size was reduced by utilizing an optical fiber with small core diameter (25 μm) in a vacuum matrix-assisted laser desorption ionization-linear ion trap (vMALDI-LTQ) mass spectrometer. Matrix application was greatly improved using oscillating capillary nebulizer. As a result, single cell level spatial resolution of ~ 12 μm was achieved. MS imaging at this high spatial resolution was directly applied to a whole Arabidopsis flower and the substructures of an anther and single pollen grains at the stigma and anther were successfully visualized. MS imaging of high spatial resolution was also demonstrated to the secondary roots of Arabidopsis thaliana and a high degree of localization of detected metabolites was successfully unveiled. This was the first MS imaging on the root for molecular species. MS imaging with high mass resolution was also achieved by utilizing the LTQ-Orbitrap mass spectrometer for the direct identification of the surface metabolites on the Arabidopsis stem and root and differentiation of isobaric ions having the same nominal mass with no need of tandem mass spectrometry (MS/MS). MS imaging at high-spatial and high-mass resolution was also applied to cer1 mutant of the model system Arabidopsis thaliana to demonstrate its usefulness in biological studies and reveal associated metabolite changes in terms of spatial distribution and/or abundances compared to those of wild-type. The spatial

  1. Ionization of large homogeneous and heterogeneous clusters generated in acetylene-Ar expansions: Cluster ion polymerization

    SciTech Connect (OSTI)

    Kocisek, J.; Lengyel, J.; Farnik, M.

    2013-03-28

    Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures and analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene clusters composed of more than a hundred acetylene molecules are generated at the acetylene concentration of Almost-Equal-To 8%, while mixed species are produced at low concentrations ( Almost-Equal-To 0.7%). The electron energy dependence of the mass spectra revealed the ionization process mechanisms in clusters. The ionization above the threshold for acetylene molecule of 11.5 eV results in the main ionic fragment progression (C{sub 2}H{sub 2}){sub n}{sup +}. At the electron energies Greater-Than-Or-Slanted-Equal-To 21.5 eV above the CH+CH{sup +} dissociative ionization limit of acetylene the fragment ions nominally labelled as (C{sub 2}H{sub 2}){sub n}CH{sup +}, n Greater-Than-Or-Slanted-Equal-To 2, are observed. For n Less-Than-Or-Slanted-Equal-To 7 these fragments correspond to covalently bound ionic structures as suggested by the observed strong dehydrogenation [(C{sub 2}H{sub 2}){sub n}-k Multiplication-Sign H]{sup +} and [(C{sub 2}H{sub 2}){sub n}CH -k Multiplication-Sign H]{sup +}. The dehydrogenation is significantly reduced in the mixed clusters where evaporation of Ar instead of hydrogen can stabilize the nascent molecular ion. The C{sub 3}H{sub 3}{sup +} ion was previously assigned to originate from the benzene molecular ion; however, the low appearance energy of Almost-Equal-To 13.7 eV indicates that a less rigid covalently bound structure of C{sub 6}H{sub 6}{sup +} ion must also be formed upon the acetylene cluster electron ionization. The appearance energy of Ar{sub n}(C{sub 2}H{sub 2}){sup +} fragments above Almost-Equal-To 15.1 eV indicates that the argon ionization is the first step in the fragment ion production, and the appearance energy of Ar{sub n{>=}2}(C{sub 2}H{sub 2}){sub m{>=}2}{sup +} at Almost-Equal-To 13

  2. Magnetic reconnection in a weakly ionized plasma

    SciTech Connect (OSTI)

    Leake, James E.; Lukin, Vyacheslav S.; Linton, Mark G.

    2013-06-15

    Magnetic reconnection in partially ionized plasmas is a ubiquitous phenomenon spanning the range from laboratory to intergalactic scales, yet it remains poorly understood and relatively little studied. Here, we present results from a self-consistent multi-fluid simulation of magnetic reconnection in a weakly ionized reacting plasma with a particular focus on the parameter regime of the solar chromosphere. The numerical model includes collisional transport, interaction and reactions between the species, and optically thin radiative losses. This model improves upon our previous work in Leake et al.[“Multi-fluid simulations of chromospheric magnetic reconnection in a weakly ionized reacting plasma,” Astrophys. J. 760, 109 (2012)] by considering realistic chromospheric transport coefficients, and by solving a generalized Ohm's law that accounts for finite ion-inertia and electron-neutral drag. We find that during the two dimensional reconnection of a Harris current sheet with an initial width larger than the neutral-ion collisional coupling scale, the current sheet thins until its width becomes less than this coupling scale, and the neutral and ion fluids decouple upstream from the reconnection site. During this process of decoupling, we observe reconnection faster than the single-fluid Sweet-Parker prediction, with recombination and plasma outflow both playing a role in determining the reconnection rate. As the current sheet thins further and elongates, it becomes unstable to the secondary tearing instability, and plasmoids are seen. The reconnection rate, outflows, and plasmoids observed in this simulation provide evidence that magnetic reconnection in the chromosphere could be responsible for jet-like transient phenomena such as spicules and chromospheric jets.

  3. Waveshifters and Scintillators for Ionizing Radiation Detection

    SciTech Connect (OSTI)

    B.Baumgaugh; J.Bishop; D.Karmgard; J.Marchant; M.McKenna; R.Ruchti; M.Vigneault; L.Hernandez; C.Hurlbut

    2007-12-11

    Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments.

  4. Resonance ionization detection of combustion radicals

    SciTech Connect (OSTI)

    Cool, T.A.

    1993-12-01

    Fundamental research on the combustion of halogenated organic compounds with emphasis on reaction pathways leading to the formation of chlorinated aromatic compounds and the development of continuous emission monitoring methods will assist in DOE efforts in the management and disposal of hazardous chemical wastes. Selective laser ionization techniques are used in this laboratory for the measurement of concentration profiles of radical intermediates in the combustion of chlorinated hydrocarbon flames. A new ultrasensitive detection technique, made possible with the advent of tunable VUV laser sources, enables the selective near-threshold photoionization of all radical intermediates in premixed hydrocarbon and chlorinated hydrocarbon flames.

  5. (Resonance ionization spectroscopy and its applications)

    SciTech Connect (OSTI)

    Payne, M.G.

    1990-10-05

    The field of Resonance Ionization Spectroscopy grew out of work done in the Photophysics Group at Oak Ridge National Laboratory. As one of the original developers of this field the traveler has continued to attend this meeting on a regular basis. The traveler was originally asked to present an invited talk and to present part of a short course offered to graduate students attending the conference. Subsequently, the traveler was also asked to chair a session and to be a judge of the students papers entered in a contest for a $1000 first prize.

  6. Market Research Survey of Commercial Off-the-Shelf Mass Spectrometers for In-Field Analysis. FY 15 Update

    SciTech Connect (OSTI)

    Yoshida, Thomas M.; Leibman, Christopher Patrick; Stark, Peter C.

    2015-11-12

    This report is an update of the 2013 Market Research Survey1-3 of field-deployable commercial off-the-shelf (COTS) mass spectrometry instruments for safeguards application.

  7. Laser ablation molecular isotopic spectrometry of carbon isotopes

    SciTech Connect (OSTI)

    Bol'shakov, Alexander A.; Jain, Jinesh; Russo, Richard E.; McIntyre, Dustin; Mao, Xianglei

    2015-08-28

    Quantitative determination of carbon isotopes using Laser Ablation Molecular Isotopic Spectrometry (LAMIS) is described. Optical emission of diatomic molecules CN and C2 is used in these measurements. Two quantification approaches are presented:empirical calibration of spectra using a set of reference standards and numerical fitting of a simulated spectrum to the experimental one. Formation mechanisms of C2 and CN in laser ablation plasma are briefly reviewed to provide insights for implementation of LAMIS measurements. A simulated spectrum of the 12C2 Swan system was synthesized using four constituents within 473.5–476.5 nm. Simulation included three branches of 12C2 (1-0), branches R(0-0) and R(1-1), and branch P(9-8) of 12C2. Spectral positions of the tail lines in R(0-0) and R(1-1) were experimentally measured, since they were not accurately known before. The Swan band (1-0) of the isotopologue 13C12C was also simulated. Fitting to the experimental spectrumyielded the ratio 13C/12C = 1.08% in a good agreement with measurements by isotope ratio mass spectrometry. LAMIS promises to be useful in coal, oil and shale exploration, carbon sequestration monitoring, and agronomy studies

  8. Hand and shoe monitor using air ionization probes

    DOE Patents [OSTI]

    Fergus, Richard W.

    1981-01-01

    A hand and shoe radiation monitor is provided which includes a probe support body defining a plurality of cells, within each cell there being an ionization probe. The support body provides structural strength for protecting the ionization probes from force applied to the support body during a radiation monitoring event. There is also provided a fast response time amplifier circuit for the output from the ionization probes.

  9. Fe Atomic Data for Non-equilibrium Ionization Plasmas Eriksen...

    Office of Scientific and Technical Information (OSTI)

    Fe Atomic Data for Non-equilibrium Ionization Plasmas Eriksen, Kristoffer A. Los Alamos National Laboratory; Fontes, Christopher J. Los Alamos National Laboratory; Colgan,...

  10. Dwarf Galaxies with Ionizing Radiation Feedback II: Spatially...

    Office of Scientific and Technical Information (OSTI)

    Star Formation Relation Citation Details In-Document Search Title: Dwarf Galaxies with Ionizing Radiation Feedback II: Spatially-resolved Star Formation Relation Authors: Kim, ...

  11. Ionized channel generation of an intense-relativistic electron beam

    DOE Patents [OSTI]

    Frost, Charles A.; Leifeste, Gordon T.; Shope, Steven L.

    1988-01-01

    A foilless intense relativistic electron beam generator uses an ionized cnel to guide electrons from a cathode passed an anode to a remote location.

  12. Pulsed Ionization Source for Ion Mobility Spectrometers - Energy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    diffusion-limited resolution. In addition, the radioactive ion sources used in many IMSs present potential safety and hazardous waste disposal issues. Other ionization sources...

  13. Interface for liquid chromatograph-mass spectrometer

    DOE Patents [OSTI]

    Andresen, Brian D.; Fought, Eric R.

    1989-01-01

    A moving belt interface for real-time, high-performance liquid chromatograph (HPLC)/mass spectrometer (MS) analysis which strips away the HPLC solvent as it emerges from the end of the HPLC column and leaves a residue suitable for mass-spectral analysis. The interface includes a portable, stand-alone apparatus having a plural stage vacuum station, a continuous ribbon or belt, a drive train magnetically coupled to an external drive motor, a calibrated HPLC delivery system, a heated probe tip and means located adjacent the probe tip for direct ionization of the residue on the belt. The interface is also capable of being readily adapted to fit any mass spectrometer.

  14. Interface for liquid chromatograph-mass spectrometer

    DOE Patents [OSTI]

    Andresen, B.D.; Fought, E.R.

    1989-09-19

    A moving belt interface is described for real-time, high-performance liquid chromatograph (HPLC)/mass spectrometer (MS) analysis which strips away the HPLC solvent as it emerges from the end of the HPLC column and leaves a residue suitable for mass-spectral analysis. The interface includes a portable, stand-alone apparatus having a plural stage vacuum station, a continuous ribbon or belt, a drive train magnetically coupled to an external drive motor, a calibrated HPLC delivery system, a heated probe tip and means located adjacent the probe tip for direct ionization of the residue on the belt. The interface is also capable of being readily adapted to fit any mass spectrometer. 8 figs.

  15. Time-of-flight detector for heavy ion backscattering spectrometry

    SciTech Connect (OSTI)

    Knapp, J.A.; Banks, J.C.; Doyle, B.L.

    1994-04-01

    This report describes the results of a two-year laboratory directed research and development project to explore advanced concepts in Heavy Ion Backscattering Spectrometry (HIBS), undertaken with the goal of extending the sensitivity of this relatively new technique to levels unattainable by any other existing trace element surface analysis. Improvements in sensitivity are required for the application of HIBS to contamination control in the microelectronics industry. Tools with sensitivity approaching 10{sup 8} atoms/cm{sup 2} are expected to be essential for enabling advanced IC production by the year 2000. During the project the authors developed a new analysis chamber with channeling goniometer and a prototype time-of-flight detector with a demonstrated sensitivity of {approximately} 5 {times} 10{sup 8} atoms/cm{sup 2} for Au on Si and {approximately} 5 {times} 10{sup 10} for Fe, and sufficient mass resolution to separate contributions from Fe and Cu.

  16. High-precision Penning trap mass measurements for tests of the Standard Model

    SciTech Connect (OSTI)

    Blaum, Klaus; Eliseev, Sergey; Nagy, Szilard

    2010-08-04

    With the nowadays achievable accuracy in Penning trap mass spectrometry on short-lived exotic nuclides as well as stable atoms, precision fundamental tests can be performed, among them a test of the Standard Model, in particular with regard to the weak interaction, the CPT symmetry conservation, and the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. In addition, accurate mass values of specific nuclides are important for neutrino physics. The presently best tests of the Standard Model with high-precision Penning trap mass spectrometry will be reviewed.

  17. Combined distance-of-flight and time-of-flight mass spectrometer

    DOE Patents [OSTI]

    Enke, Christie G; Ray, Steven J; Graham, Alexander W; Hieftje, Gary M; Barinaga, Charles J; Koppenaal, David W

    2014-02-11

    A combined distance-of-flight mass spectrometry (DOFMS) and time-of-flight mass spectrometry (TOFMS) instrument includes an ion source configured to produce ions having varying mass-to-charge ratios, a first detector configured to determine when each of the ions travels a predetermined distance, a second detector configured to determine how far each of the ions travels in a predetermined time, and a detector extraction region operable to direct portions of the ions either to the first detector or to the second detector.

  18. Ionization source utilizing a jet disturber in combination with an ion funnel and method of operation

    DOE Patents [OSTI]

    Smith, Richard D.; Kim, Taeman; Tang, Keqi; Udseth, Harold R.

    2003-06-24

    A jet disturber used in combination with an ion funnel to focus ions and other charged particles generated at or near atmospheric pressure into a relatively low pressure region, which allows increased conductance of the ions and other charged particles. The jet disturber is positioned within an ion funnel and may be interfaced with a multi-capillary inlet juxtaposed between an ion source and the interior of an instrument maintained at near atmospheric pressure. The invention finds particular advantages when deployed to improve the ion transmission between an electrospray ionization source and the first vacuum stage of a mass spectrometer.

  19. Spectroscopy of triply and quadruply ionized states of mercury

    SciTech Connect (OSTI)

    Huttula, M.; Huttula, S.-M.; Lablanquie, P.; Palaudoux, J.; Penent, F.; Andric, L.; Eland, J. H. D.

    2011-03-15

    Multielectron coincidence spectroscopy has been used to study multiple ionization of atomic mercury. The binding energies of triply and quadruply ionized states of Hg have been determined from three- and fourfold electron coincidences. Relativistic ab initio theory has been used to calculate the state energies and predict the experimental findings.

  20. Mass dependency of turbulent parameters in stationary glow discharge plasmas

    SciTech Connect (OSTI)

    Titus, J. B.; Alexander, A. B.; Wiggins, D. L.; Johnson, J. A. III

    2013-05-15

    A direct current glow discharge tube is used to determine how mass changes the effects of certain turbulence characteristics in a weakly ionized gas. Helium, neon, argon, and krypton plasmas were created, and an axial magnetic field, varied from 0.0 to 550.0 Gauss, was used to enhance mass dependent properties of turbulence. From the power spectra of light emission variations associated with velocity fluctuations, determination of mass dependency on turbulent characteristic unstable modes, energy associated with turbulence, and the rate at which energy is transferred from scale to scale are measured. The magnetic field strength is found to be too weak to overcome particle diffusion to the walls to affect the turbulence in all four types of plasmas, though mass dependency is still detected. Though the total energy and the rate at which the energy moves between scales are mass invariant, the amplitude of the instability modes that characterize each plasma are dependent on mass.

  1. Escape fraction of ionizing photons during reionization: Effects due to supernova feedback and runaway ob stars

    SciTech Connect (OSTI)

    Kimm, Taysun; Cen, Renyue

    2014-06-20

    The fraction of hydrogen ionizing photons escaping from galaxies into the intergalactic medium is a critical ingredient in the theory of reionization. We use two zoomed-in, high-resolution (4 pc), cosmological radiation hydrodynamic simulations with adaptive mesh refinement to investigate the impact of two physical mechanisms (supernova, SN, feedback, and runaway OB stars) on the escape fraction (f {sub esc}) at the epoch of reionization (z ? 7). We implement a new, physically motivated SN feedback model that can approximate the Sedov solutions at all (from the free expansion to snowplow) stages. We find that there is a significant time delay of about ten million years between the peak of star formation and that of escape fraction, due to the time required for the build-up and subsequent destruction of the star-forming cloud by SN feedback. Consequently, the photon number-weighted mean escape fraction for dwarf galaxies in halos of mass 10{sup 8}-10{sup 10.5} M {sub ?} is found to be ?f{sub esc}??11%, although instantaneous values of f {sub esc} > 20% are common when star formation is strongly modulated by the SN explosions. We find that the inclusion of runaway OB stars increases the mean escape fraction by 22% to ?f{sub esc}??14%. As SNe resulting from runaway OB stars tend to occur in less dense environments, the feedback effect is enhanced and star formation is further suppressed in halos with M{sub vir}?10{sup 9} M{sub ?} in the simulation with runaway OB stars compared with the model without them. While both our models produce enough ionizing photons to maintain a fully ionized universe at z ? 7 as observed, a still higher amount of ionizing photons at z ? 9 appears necessary to accommodate the high observed electron optical depth inferred from cosmic microwave background observations.

  2. Compact mass spectrometer for plasma discharge ion analysis

    DOE Patents [OSTI]

    Tuszewski, M.G.

    1997-07-22

    A mass spectrometer and methods are disclosed for mass spectrometry which are useful in characterizing a plasma. This mass spectrometer for determining type and quantity of ions present in a plasma is simple, compact, and inexpensive. It accomplishes mass analysis in a single step, rather than the usual two-step process comprised of ion extraction followed by mass filtering. Ions are captured by a measuring element placed in a plasma and accelerated by a known applied voltage. Captured ions are bent into near-circular orbits by a magnetic field such that they strike a collector, producing an electric current. Ion orbits vary with applied voltage and proton mass ratio of the ions, so that ion species may be identified. Current flow provides an indication of quantity of ions striking the collector. 7 figs.

  3. Compact mass spectrometer for plasma discharge ion analysis

    DOE Patents [OSTI]

    Tuszewski, Michel G.

    1997-01-01

    A mass spectrometer and methods for mass spectrometry which are useful in characterizing a plasma. This mass spectrometer for determining type and quantity of ions present in a plasma is simple, compact, and inexpensive. It accomplishes mass analysis in a single step, rather than the usual two-step process comprised of ion extraction followed by mass filtering. Ions are captured by a measuring element placed in a plasma and accelerated by a known applied voltage. Captured ions are bent into near-circular orbits by a magnetic field such that they strike a collector, producing an electric current. Ion orbits vary with applied voltage and proton mass ratio of the ions, so that ion species may be identified. Current flow provides an indication of quantity of ions striking the collector.

  4. GoAmazon 2014/15 Thermal Desorption Chemical Ionization Mass...

    Office of Scientific and Technical Information (OSTI)

    of Energy (DOE)'s Atmospheric Radiation Measurement (ARM) Climate Research Facility T3 site in Manacapuru, Brazil, was motivated by two main scientific objectives of the Green ...

  5. GoAmazon2014-15 Thermal Desorption Chemical Ionization Mass Spectromer...

    Office of Scientific and Technical Information (OSTI)

    (TDCIMS) Field Campaign Report JN Smith April 2016 CLIMATE RESEARCH FACILITY ... (TDCIMS) Field Campaign Report JN Smith, University of California, Irvine ...

  6. GoAmazon2014-15 Thermal Desorption Chemical Ionization Mass Spectromer...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (TDCIMS) Field Campaign Report JN Smith April 2016 DISCLAIMER This report was ... (TDCIMS) Field Campaign Report JN Smith, University of California, Irvine ...

  7. Laser stripping of hydrogen atoms by direct ionization

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Brunetti, E.; Becker, W.; Bryant, H. C.; Jaroszynski, D. A.; Chou, W.

    2015-05-08

    Direct ionization of hydrogen atoms by laser irradiation is investigated as a potential new scheme to generate proton beams without stripping foils. The time-dependent Schrödinger equation describing the atom-radiation interaction is numerically solved obtaining accurate ionization cross-sections for a broad range of laser wavelengths, durations and energies. Parameters are identified where the Doppler frequency up-shift of radiation colliding with relativistic particles can lead to efficient ionization over large volumes and broad bandwidths using currently available lasers.

  8. Subcellular-level resolution MALDI-MS imaging of maize leaf metabolites by MALDI-linear ion trap-Orbitrap mass spectrometer

    SciTech Connect (OSTI)

    Korte, Andrew R.; Yandeau-Nelson, Marna D.; Nikolau, Basil J.; Lee, Young Jin

    2015-01-25

    A significant limiting factor in achieving high spatial resolution for matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) imaging is the size of the laser spot at the sample surface. We present modifications to the beam-delivery optics of a commercial MALDI-linear ion trap-Orbitrap instrument, incorporating an external Nd:YAG laser, beam-shaping optics, and an aspheric focusing lens, to reduce the minimum laser spot size from ~50 μm for the commercial configuration down to ~9 μm for the modified configuration. This improved system was applied for MALDI-MS imaging of cross sections of juvenile maize leaves at 5-μm spatial resolution using an oversampling method. There are a variety of different metabolites including amino acids, glycerolipids, and defense-related compounds were imaged at a spatial resolution well below the size of a single cell. Such images provide unprecedented insights into the metabolism associated with the different tissue types of the maize leaf, which is known to asymmetrically distribute the reactions of C4 photosynthesis among the mesophyll and bundle sheath cell types. The metabolite ion images correlate with the optical images that reveal the structures of the different tissues, and previously known and newly revealed asymmetric metabolic features are observed.

  9. Subcellular-level resolution MALDI-MS imaging of maize leaf metabolites by MALDI-linear ion trap-Orbitrap mass spectrometer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Korte, Andrew R.; Yandeau-Nelson, Marna D.; Nikolau, Basil J.; Lee, Young Jin

    2015-01-25

    A significant limiting factor in achieving high spatial resolution for matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) imaging is the size of the laser spot at the sample surface. We present modifications to the beam-delivery optics of a commercial MALDI-linear ion trap-Orbitrap instrument, incorporating an external Nd:YAG laser, beam-shaping optics, and an aspheric focusing lens, to reduce the minimum laser spot size from ~50 μm for the commercial configuration down to ~9 μm for the modified configuration. This improved system was applied for MALDI-MS imaging of cross sections of juvenile maize leaves at 5-μm spatial resolution using an oversampling method. Theremore » are a variety of different metabolites including amino acids, glycerolipids, and defense-related compounds were imaged at a spatial resolution well below the size of a single cell. Such images provide unprecedented insights into the metabolism associated with the different tissue types of the maize leaf, which is known to asymmetrically distribute the reactions of C4 photosynthesis among the mesophyll and bundle sheath cell types. The metabolite ion images correlate with the optical images that reveal the structures of the different tissues, and previously known and newly revealed asymmetric metabolic features are observed.« less

  10. Focused analyte spray emission apparatus and process for mass spectrometric analysis

    DOE Patents [OSTI]

    Roach, Patrick J.; Laskin, Julia; Laskin, Alexander

    2012-01-17

    An apparatus and process are disclosed that deliver an analyte deposited on a substrate to a mass spectrometer that provides for trace analysis of complex organic analytes. Analytes are probed using a small droplet of solvent that is formed at the junction between two capillaries. A supply capillary maintains the droplet of solvent on the substrate; a collection capillary collects analyte desorbed from the surface and emits analyte ions as a focused spray to the inlet of a mass spectrometer for analysis. The invention enables efficient separation of desorption and ionization events, providing enhanced control over transport and ionization of the analyte.

  11. Multiple ionization of Ar by F{sup -} impact: Projectile-electron-loss and direct-ionization collision channels

    SciTech Connect (OSTI)

    Sant'Anna, M. M.; Zappa, F.; Santos, A. C. F.; Coelho, L. F. S.; Wolff, W.; Barros, A. L. F. de; Castro Faria, N. V. de

    2006-08-15

    We have measured single- and multiple-target ionization cross sections for the F{sup -}+Ar collision system. Measurements of the final target and projectile charge states were performed in coincidence, separating the collision channels for single-, double-, and triple-projectile-electron loss and for direct ionization. The studied velocity region extends from v=0.46 to v=1.45 atomic units. Results are compared with existing H{sup -}+Ar data as well as with Ar multiple ionization by protons, electrons, and antiprotons. For the direct-ionization channel, ratios for multiple-to-single target ionization are similar to those found for H{sup +}+Ar collisions. For this channel multiple ionization is well described by independent single-ionization events by a frozen projectile. For the projectile-electron-loss collision channels, on the other hand, the correlation between projectile electrons and target electrons plays an important role. Our data show that the average final charge state of the target, , increases steeply with the final charge state of the projectile, while an independent-particle model (neglecting two-center electron-electron correlation) only accounts for small variations of .

  12. Systems and methods for cylindrical hall thrusters with independently controllable ionization and acceleration stages

    DOE Patents [OSTI]

    Diamant, Kevin David; Raitses, Yevgeny; Fisch, Nathaniel Joseph

    2014-05-13

    Systems and methods may be provided for cylindrical Hall thrusters with independently controllable ionization and acceleration stages. The systems and methods may include a cylindrical channel having a center axial direction, a gas inlet for directing ionizable gas to an ionization section of the cylindrical channel, an ionization device that ionizes at least a portion of the ionizable gas within the ionization section to generate ionized gas, and an acceleration device distinct from the ionization device. The acceleration device may provide an axial electric field for an acceleration section of the cylindrical channel to accelerate the ionized gas through the acceleration section, where the axial electric field has an axial direction in relation to the center axial direction. The ionization section and the acceleration section of the cylindrical channel may be substantially non-overlapping.

  13. AN INITIAL MASS FUNCTION STUDY OF THE DWARF STARBURST GALAXY NGC 4214

    SciTech Connect (OSTI)

    Andrews, J. E.; Calzetti, D.; Chandar, R.; Lee, J. C.; Whitmore, B.; Elmegreen, B. G.; Kennicutt, R. C.; Kissel, J. S.; Da Silva, Robert L.; Krumholz, Mark R.; O'Connell, R. W.; Dopita, M. A.; Frogel, Jay A.; Kim, Hwihyun E-mail: callzetti@astro.umass.edu

    2013-04-10

    The production rate of ionizing photons in young ({<=}8 Myr), unresolved stellar clusters in the nearby irregular galaxy NGC 4214 is probed using multi-wavelength Hubble Space Telescope WFC3 data. We normalize the ionizing photon rate by the cluster mass to investigate the upper end of the stellar initial mass function (IMF). We have found that within the uncertainties the upper end of the stellar IMF appears to be universal in this galaxy, and that deviations from a universal IMF can be attributed to stochastic sampling of stars in clusters with masses {approx}<10{sup 3} M{sub Sun }. Furthermore, we have found that there does not seem to be a dependence of the maximum stellar mass on the cluster mass. We have also found that for massive clusters, feedback may cause an underrepresentation in H{alpha} luminosities, which needs to be taken into account when conducting this type of analysis.

  14. Soft x-ray ionization induced fragmentation of glycine

    SciTech Connect (OSTI)

    Itl, E.; Kooser, K.; Rachlew, E.; Huels, M. A.; Kukk, E.

    2014-06-21

    X-ray absorption commonly involves dissociative core ionization producing not only momentum correlated charged fragments but also low- and high-energy electrons capable of inducing damage in living tissue. This gives a natural motivation for studying the core ionization induced fragmentation processes in biologically important molecules such as amino acids. Here the fragmentation of amino acid glycine following carbon 1s core ionization has been studied. Using photoelectron-photoion-photoion coincidence technique, a detailed analysis on fragmentation of the sample molecule into pairs of momentum correlated cations has been carried out. The main characteristics of core ionization induced fragmentation of glycine were found to be the rupture of the CC{sub ?} bond and the presence of the CNH{sub 2}{sup +} fragment.

  15. Epicyclic helical channels for parametric resonance ionization cooling

    SciTech Connect (OSTI)

    Johson, Rolland Paul; Derbenev, Yaroslav

    2015-08-23

    Proposed next-generation muon colliders will require major technical advances to achieve rapid muon beam cooling requirements. Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. In PIC, a half-integer parametric resonance causes strong focusing of a muon beam at appropriately placed energy absorbers while ionization cooling limits the beam’s angular spread. Combining muon ionization cooling with parametric resonant dynamics in this way should then allow much smaller final transverse muon beam sizes than conventional ionization cooling alone. One of the PIC challenges is compensation of beam aberrations over a sufficiently wide parameter range while maintaining the dynamical stability with correlated behavior of the horizontal and vertical betatron motion and dispersion. We explore use of a coupling resonance to reduce the dimensionality of the problem and to shift the dynamics away from non-linear resonances. PIC simulations are presented.

  16. Radiation and ionization energy loss simulation for the GDH sum...

    Office of Scientific and Technical Information (OSTI)

    loss simulation for the GDH sum rule experiment in Hall-A at Jefferson Lab Citation Details In-Document Search Title: Radiation and ionization energy loss simulation for the ...

  17. Perturbation analysis of ionization oscillations in Hall effect thrusters

    SciTech Connect (OSTI)

    Hara, Kentaro Sekerak, Michael J.; Boyd, Iain D.; Gallimore, Alec D.

    2014-12-15

    A perturbation analysis of ionization oscillations, which cause low frequency oscillations of the discharge plasma, in Hall effect thrusters is presented including the electron energy equation in addition to heavy-species transport. Excitation and stabilization of such oscillations, often called the breathing mode, are discussed in terms of the growth rate obtained from the linear perturbation equations of the discharge plasma. The instability induced from the ionization occurs only when the perturbation in the electron energy is included while the neutral atom flow contributes to the damping of the oscillation. Effects of the electron energy loss mechanisms such as wall heat loss, inelastic collisions, and convective heat flux are discussed. It is shown that the ionization oscillations can be damped when the electron transport is reduced and the electron temperature increases so that the energy loss to the wall stabilizes the ionization instability.

  18. Detailed and simplified nonequilibrium helium ionization in the solar atmosphere

    SciTech Connect (OSTI)

    Golding, Thomas Peter; Carlsson, Mats; Leenaarts, Jorrit E-mail: mats.carlsson@astro.uio.no

    2014-03-20

    Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out one-dimensional radiation-hydrodynamics simulations of the solar atmosphere and find that the helium ionization is set mostly by photoionization and direct collisional ionization, counteracted by radiative recombination cascades. By introducing an additional recombination rate mimicking the recombination cascades, we construct a simplified three-level helium model atom consisting of only the ground states. This model atom is suitable for modeling nonequilibrium helium ionization in three-dimensional numerical models. We perform a brief investigation of the formation of the He I 10830 and He II 304 spectral lines. Both lines show nonequilibrium features that are not recovered with statistical equilibrium models, and caution should therefore be exercised when such models are used as a basis for interpretating observations.

  19. Fe Atomic Data for Non-equilibrium Ionization Plasmas (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Fe Atomic Data for Non-equilibrium Ionization Plasmas Citation Details In-Document Search Title: Fe Atomic Data for Non-equilibrium Ionization Plasmas No abstract prepared. Authors: Eriksen, Kristoffer A. [1] ; Fontes, Christopher J. [1] ; Colgan, James P. [1] ; Zhang, Honglin [1] ; Hungerford, Aimee L. [1] ; Fryer, Christopher L. [1] ; Hughes, John P. [2] ; Smith, Randall K. [3] ; Badenes, Carles [4] + Show Author Affiliations Los Alamos National Laboratory Rutgers

  20. Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Wednesday, 30 June 2010 00:00 Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research

  1. Paths and ionization losses of proton energy in different substances

    SciTech Connect (OSTI)

    Vasilovskiy, I.M.; Karpov, I.I.; Petrukhin, V.I.; Prokoshkin, Yu.D.

    1986-02-14

    Ionization energy losses of charged particles in a substance are described by the well-known Bethe-Bloch formula. However, the magnitudes of the ionization potentials in region of low proton energies (E < 100 MeV) for heavy elements prove to be considerably larger than those at high energies. Thus, studies of ionization losses in the region of high energies are the main source of the experimental information necessary for the correction of the Bethe-Bloch formula and determination of magnitudes of ionization potentials I. The purpose of this work was to measure the magnitudes of ionization losses dE/ds, paths R and ionization potentials I at a proton energy of E 670 MeV. The measurements were taken by the relative method for different substances of x, and the magnitudes of q sub x=(dE/ds) sub x/(dE/ds) sub Al and px=R sub x/R sub Al were found. Quantities qx and px weakly depend on the energy E where at E=200-600 MeV, a=(2-4).10-2 for different substances. The proton energy was determined with an accuracy of 2 MeV.

  2. ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA

    SciTech Connect (OSTI)

    Soler, R.; Ballester, J. L.; Terradas, J.; Carbonell, M. E-mail: joseluis.ballester@uib.es E-mail: marc.carbonell@uib.es

    2013-04-20

    Alfven waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfven waves is affected by the interaction between ionized and neutral species. Here we study Alfven waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfven waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.

  3. Lead Slowing Down Spectrometry Analysis of Data from Measurements on Nuclear Fuel

    SciTech Connect (OSTI)

    Warren, Glen A.; Anderson, Kevin K.; Kulisek, Jonathan A.; Danon, Yaron; Weltz, Adam; Gavron, Victor A.; Harris, Jason; Stewart, Trevor N.

    2015-01-12

    Improved non-destructive assay of isotopic masses in used nuclear fuel would be valuable for nuclear safeguards operations associated with the transport, storage and reprocessing of used nuclear fuel. Our collaboration is examining the feasibility of using lead slowing down spectrometry techniques to assay the isotopic fissile masses in used nuclear fuel assemblies. We present the application of our analysis algorithms on measurements conducted with a lead spectrometer. The measurements involved a single fresh fuel pin and discrete 239Pu and 235U samples. We are able to describe the isotopic fissile masses with root mean square errors over seven different configurations to 6.35% for 239Pu and 2.7% for 235U over seven different configurations. Funding Source(s):

  4. Mass spectrometric immunoassay

    DOE Patents [OSTI]

    Nelson, Randall W.; Williams, Peter; Krone, Jennifer Reeve

    2005-12-13

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  5. Mass spectrometric immunoassay

    DOE Patents [OSTI]

    Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

    2013-07-16

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  6. Mass spectrometric immunoassay

    DOE Patents [OSTI]

    Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

    2007-12-04

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  7. DWARF GALAXIES WITH IONIZING RADIATION FEEDBACK. I. ESCAPE OF IONIZING PHOTONS

    SciTech Connect (OSTI)

    Kim, Ji-hoon; Krumholz, Mark R.; Goldbaum, Nathan J.; Wise, John H.; Turk, Matthew J.; Abel, Tom

    2013-10-01

    We describe a new method for simulating ionizing radiation and supernova feedback in the analogs of low-redshift galactic disks. In this method, which we call star-forming molecular cloud (SFMC) particles, we use a ray-tracing technique to solve the radiative transfer equation for ultraviolet photons emitted by thousands of distinct particles on the fly. Joined with high numerical resolution of 3.8 pc, the realistic description of stellar feedback helps to self-regulate star formation. This new feedback scheme also enables us to study the escape of ionizing photons from star-forming clumps and from a galaxy, and to examine the evolving environment of star-forming gas clumps. By simulating a galactic disk in a halo of 2.3 10{sup 11} M{sub ?}, we find that the average escape fraction from all radiating sources on the spiral arms (excluding the central 2.5 kpc) fluctuates between 0.08% and 5.9% during a ?20 Myr period with a mean value of 1.1%. The flux of escaped photons from these sources is not strongly beamed, but manifests a large opening angle of more than 60 from the galactic pole. Further, we investigate the escape fraction per SFMC particle, f{sub esc}(i), and how it evolves as the particle ages. We discover that the average escape fraction f{sub esc} is dominated by a small number of SFMC particles with high f{sub esc}(i). On average, the escape fraction from an SFMC particle rises from 0.27% at its birth to 2.1% at the end of a particle lifetime, 6 Myr. This is because SFMC particles drift away from the dense gas clumps in which they were born, and because the gas around the star-forming clumps is dispersed by ionizing radiation and supernova feedback. The framework established in this study brings deeper insight into the physics of photon escape fraction from an individual star-forming clump and from a galactic disk.

  8. Imaging mass spectrometer with mass tags

    DOE Patents [OSTI]

    Felton, James S.; Wu, Kuang Jen; Knize, Mark G.; Kulp, Kristen S.; Gray, Joe W.

    2010-06-01

    A method of analyzing biological material by exposing the biological material to a recognition element, that is coupled to a mass tag element, directing an ion beam of a mass spectrometer to the biological material, interrogating at least one region of interest area from the biological material and producing data, and distributing the data in plots.

  9. Imaging mass spectrometer with mass tags

    DOE Patents [OSTI]

    Felton, James S.; Wu, Kuang Jen J.; Knize, Mark G.; Kulp, Kristen S.; Gray, Joe W.

    2013-01-29

    A method of analyzing biological material by exposing the biological material to a recognition element, that is coupled to a mass tag element, directing an ion beam of a mass spectrometer to the biological material, interrogating at least one region of interest area from the biological material and producing data, and distributing the data in plots.

  10. EXTENDING THE USEFUL LIFE OF OLDER MASS SPECTROMETERS

    SciTech Connect (OSTI)

    Johnson, S.; Cordaro, J.; Holland, M.; Jones, V.

    2010-06-17

    Thermal ionization and gas mass spectrometers are widely used across the Department of Energy (DOE) Complex and contractor laboratories. These instruments support critical missions, where high reliability and low measurement uncertainty are essential. A growing number of these mass spectrometers are significantly older than their original design life. The reality is that manufacturers have declared many of the instrument models obsolete, with direct replacement parts and service no longer available. Some of these obsolete models do not have a next generation, commercially available replacement. Today's budget conscious economy demands for the use of creative funds management. Therefore, the ability to refurbish (or upgrade) these valuable analytical tools and extending their useful life is a cost effective option. The Savannah River Site (SRS) has the proven expertise to breathe new life into older mass spectrometers, at a significant cost savings compared to the purchase and installation of new instruments. A twenty-seven year old Finnigan MAT-261{trademark} Thermal Ionization Mass Spectrometer (TIMS), located at the SRS F/H Area Production Support Laboratory, has been successfully refurbished. Engineers from the Savannah River National Laboratory (SRNL) fabricated and installed the new electronics. These engineers also provide continued instrument maintenance services. With electronic component drawings being DOE Property, other DOE Complex laboratories have the option to extend the life of their aged Mass Spectrometers.

  11. THE EFFECT OF GALACTIC PROPERTIES ON THE ESCAPE FRACTION OF IONIZING PHOTONS

    SciTech Connect (OSTI)

    Fernandez, Elizabeth R.; Shull, J. Michael E-mail: michael.shull@colorado.edu

    2011-04-10

    The escape fraction, f{sub esc}, of ionizing photons from early galaxies is a crucial parameter for determining whether the observed galaxies at z {>=} 6 are able to reionize the high-redshift intergalactic medium. Previous attempts to measure f{sub esc} have found a wide range of values, varying from less than 0.01 to nearly 1. Rather than finding a single value of f{sub esc}, we clarify through modeling how internal properties of galaxies affect f{sub esc} through the density and distribution of neutral hydrogen within the galaxy, along with the rate of ionizing photons' production. We find that the escape fraction depends sensitively on the covering factor of clumps, along with the density of the clumped and interclump medium. One must therefore be cautious when dealing with an inhomogeneous medium. Fewer high-density clumps lead to a greater escape fraction than more numerous low-density clumps. When more ionizing photons are produced in a starburst, f{sub esc} increases, as photons escape more readily from the gas layers. Large variations in the predicted escape fraction, caused by differences in the hydrogen distribution, may explain the large observed differences in f{sub esc} among galaxies. Values of f{sub esc} must also be consistent with the reionization history. High-mass galaxies alone are unable to reionize the universe, because f{sub esc} >1 would be required. Small galaxies are needed to achieve reionization, with greater mean escape fraction in the past.

  12. Inner-shell and double ionization potentials of aminophenol isomers.

    SciTech Connect (OSTI)

    Kryzhevoi, N. V.; Santra, R.; Cederbaum, L. S.

    2011-01-01

    A comprehensive study of single and double core ionization potentials of the aminophenol molecule is reported. The role of relaxation, correlation, relativistic, and basis set effects in these potentials is clarified. Special attention is paid to the isomer dependence of the single and double core ionization potentials. Some of them are also compared with the respective values of the phenol and aniline molecules. It is shown that the core level single ionization potentials of the para-, meta-, and ortho-aminophenol molecules differ only slightly from each other, rendering these structural isomers challenging to distinguish for conventional x-ray photoelectron spectroscopy. In contrast, the energy needed to remove two core electrons from different atoms depends noticeably on the mutual arrangement and even on the relative orientations of the hydroxyl and amine groups. Together with the electrostatic repulsion between the two core holes, relaxation effects accompanying double core ionization play a crucial role here. The pronounced sensitivity of the double ionization potentials, therefore, enables a spectroscopic characterization of the electronic structure of aminophenol isomers by means of x-ray two-photon photoelectron spectroscopy.

  13. Application of Spatially Resolved High Resolution Crystal Spectrometry...

    Office of Scientific and Technical Information (OSTI)

    Crystal Spectrometry to ICF Plasmas Kenneth W. Hill, et. al. 70 PLASMA PHYSICS AND FUSION TECHNOLOGY High Temperature High Temperature High resolution (3; 10 000) 1D...

  14. Use of MCNPX for Alpha Spectrometry Simulations of a Continuous...

    Office of Scientific and Technical Information (OSTI)

    spectrum in a Passive Implanted Planar Silicon (PIPS) detector, as modeled by MCNPX 1, ... PROGENY; RADIOISOTOPES; RADON; SILICON Alpha Spectrometry, Continuous Air ...

  15. NMIS With Gamma Spectrometry for Attributes of Pu and HEU, Explosives and Chemical Agents

    SciTech Connect (OSTI)

    Mihalczo, J. T.; Mattingly, J. K.; Mullens, J. A.; Neal, J. S.

    2002-05-10

    The concept for the system described herein is an active/passive Nuclear Materials Identification System{sup 2} (NMIS) that incorporates gamma ray spectrometry{sup 3}. This incorporation of gamma ray spectrometry would add existing capability into this system. This Multiple Attribute System can determine a wide variety of attributes for Pu and highly enriched uranium (HEU) of which a selected subset could be chosen. This system can be built using commercial off the shelf (COTS) components. NMIS systems are at All-Russian Scientific Research Institute of Experimental Physics (VNIIEF) and Russian Federal Nuclear Center Institute of Technical Physics, (VNIITF) and measurements with Pu have been performed at VNIIEF and analyzed successfully for mass and thickness of Pu. NMIS systems are being used successfully for HEU at the Y-12 National Security Complex. The use of active gamma ray spectrometry for high explosive HE and chemical agent detection is a well known activation analysis technique, and it is incorporated here. This report describes the system, explains the attribute determination methods for fissile materials, discusses technical issues to be resolved, discusses additional development needs, presents a schedule for building from COTS components, and assembly with existing components, and discusses implementation issues such as lack of need for facility modification and low radiation exposure.

  16. Neutron spectrometry for UF6 enrichment verification in storage cylinders

    SciTech Connect (OSTI)

    Mengesha, Wondwosen; Kiff, Scott D.

    2015-01-29

    Verification of declared UF6 enrichment and mass in storage cylinders is of great interest in nuclear material nonproliferation. Nondestructive assay (NDA) techniques are commonly used for safeguards inspections to ensure accountancy of declared nuclear materials. Common NDA techniques used include gamma-ray spectrometry and both passive and active neutron measurements. In the present study, neutron spectrometry was investigated for verification of UF6 enrichment in 30B storage cylinders based on an unattended and passive measurement approach. MCNP5 and Geant4 simulated neutron spectra, for selected UF6 enrichments and filling profiles, were used in the investigation. The simulated neutron spectra were analyzed using principal component analysis (PCA). The PCA technique is a well-established technique and has a wide area of application including feature analysis, outlier detection, and gamma-ray spectral analysis. Results obtained demonstrate that neutron spectrometry supported by spectral feature analysis has potential for assaying UF6 enrichment in storage cylinders. The results from the present study also showed that difficulties associated with the UF6 filling profile and observed in other unattended passive neutron measurements can possibly be overcome using the approach presented.

  17. Neutron spectrometry for ${\\rm UF}_6$ enrichment verification in storage cylinders

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mengesha, Wondwosen; Kiff, Scott D.

    2015-01-29

    Verification of declared UF6 enrichment and mass in storage cylinders is of great interest in nuclear material nonproliferation. Nondestructive assay (NDA) techniques are commonly used for safeguards inspections to ensure accountancy of declared nuclear materials. Common NDA techniques used include gamma-ray spectrometry and both passive and active neutron measurements. In the present study, neutron spectrometry was investigated for verification of UF6 enrichment in 30B storage cylinders based on an unattended and passive measurement approach. MCNP5 and Geant4 simulated neutron spectra, for selected UF6 enrichments and filling profiles, were used in the investigation. The simulated neutron spectra were analyzed using principalmorecomponent analysis (PCA). The PCA technique is a well-established technique and has a wide area of application including feature analysis, outlier detection, and gamma-ray spectral analysis. Results obtained demonstrate that neutron spectrometry supported by spectral feature analysis has potential for assaying UF6 enrichment in storage cylinders. The results from the present study also showed that difficulties associated with the UF6 filling profile and observed in other unattended passive neutron measurements can possibly be overcome using the approach presented.less

  18. Laser desorption time-of-flight mass spectrometer DNA analyzer. Final report

    SciTech Connect (OSTI)

    Chen, C.H.W.; Martin, S.A.

    1997-02-01

    The objective of this project is the development of a laser desorption time-of-flight mass spectrometer DNA analyzer which can be broadly used for biomedical research. Tasks include: pulsed ion extraction to improve resolution; two-component matrices to enhance ionization; and solid phase DNA purification.

  19. Differentiation of Microbial Species and Strains in Coculture Biofilms by Multivariate Analysis of Laser Desorption Postionization Mass Spectra

    SciTech Connect (OSTI)

    University of Illinois at Chicago; Montana State University; Bhardwaj, Chhavi; Cui, Yang; Hofstetter, Theresa; Liu, Suet Yi; Bernstein, Hans C.; Carlson, Ross P.; Ahmed, Musahid; Hanley, Luke

    2013-04-01

    7.87 to 10.5 eV vacuum ultraviolet (VUV) photon energies were used in laser desorption postionization mass spectrometry (LDPI-MS) to analyze biofilms comprised of binary cultures of interacting microorganisms. The effect of photon energy was examined using both tunable synchrotron and laser sources of VUV radiation. Principal components analysis (PCA) was applied to the MS data to differentiate species in Escherichia coli-Saccharomyces cerevisiae coculture biofilms. PCA of LDPI-MS also differentiated individual E. coli strains in a biofilm comprised of two interacting gene deletion strains, even though these strains differed from the wild type K-12 strain by no more than four gene deletions each out of approximately 2000 genes. PCA treatment of 7.87 eV LDPI-MS data separated the E. coli strains into three distinct groups two ?pure? groups and a mixed region. Furthermore, the ?pure? regions of the E. coli cocultures showed greater variance by PCA when analyzed by 7.87 eV photon energies than by 10.5 eV radiation. Comparison of the 7.87 and 10.5 eV data is consistent with the expectation that the lower photon energy selects a subset of low ionization energy analytes while 10.5 eV is more inclusive, detecting a wider range of analytes. These two VUV photon energies therefore give different spreads via PCA and their respective use in LDPI-MS constitute an additional experimental parameter to differentiate strains and species.

  20. Down-regulation of PERK enhances resistance to ionizing radiation

    SciTech Connect (OSTI)

    Oommen, Deepu Prise, Kevin M.

    2013-11-08

    Highlights: •PERK enhances the sensitivity of cancer cells to ionizing radiation. •Down-regulation of PERK results in enhanced DNA repair. •Ionizing radiation-induced apoptosis is inhibited in PERK-down regulated cancer cells. -- Abstract: Although, ionizing radiation (IR) has been implicated to cause stress in endoplasmic reticulum (ER), how ER stress signaling and major ER stress sensors modulate cellular response to IR is unclear. Protein kinase RNA-like endoplasmic reticulum kinase (PERK) is an ER transmembrane protein which initiates unfolded protein response (UPR) or ER stress signaling when ER homeostasis is disturbed. Here, we report that down-regulation of PERK resulted in increased clonogenic survival, enhanced DNA repair and reduced apoptosis in irradiated cancer cells. Our study demonstrated that PERK has a role in sensitizing cancer cells to IR.

  1. Genetic variation in resistance to ionizing radiation. [Annual report, 1989

    SciTech Connect (OSTI)

    Ayala, F.J.

    1989-12-31

    The very reactive superoxide anion O{sub 2} is generated during cell respiration as well as during exposure to ionizing radiation. Organisms have evolved different mechanisms to protect against the deleterious effects of reduced oxygen species. The copper-zinc superoxide dismutase is a eukaryotic cytoplasmic enzyme that protects the cell by scavenging superoxide radicals and dismutating them to hydrogen peroxide and molecular oxygen: 20{sub 2}{sup {minus}} + 2H {yields} H{sub 2}O{sub 2} + O{sub 2}. SOD had been shown to protect against ionizing radiation damage to DNA, viruses, bacteria, mammalian cells, whole mice, and Drosophila. Evidence that genetic differences may affect sensitivity to ionizing radiation has been shown in Drosophila since differences have been shown to exist between strains and resistance to radiation can evolve under natural selection.

  2. Studies of ground-state dynamics in isolated species by ionization-detected stimulated Raman techniques

    SciTech Connect (OSTI)

    Felker, P.M.

    1993-12-01

    First, the author aims to develop methods of nonlinear Raman spectroscopy for application in studies of sparse samples. Second, the author wishes to apply such methods to structural and dynamical studies of species (molecules, complexes, and clusters) in supersonic molecular beams. In the past year, the author has made progress in several areas. The first pertains to the application of mass-selective ionization-detected stimulated Raman spectroscopies (IDSRS) to the size-specific vibrational spectroscopy of solute-solvent{sub n} clusters. The second involves the application of IDSRS methods to studies of jet-cooled benzene clusters. The third pertains to the use of IDSRS methods in the study of intermolecular vibrational transitions in van der Waals complexes.

  3. Dispersion of seed vapor and gas ionization in an MHD second stage combustor and channel

    SciTech Connect (OSTI)

    Chang, S.L.; Lottes, S.A.; Bouillard, J.X.

    1992-01-01

    An approach is introduced for the simulation of a magnetohydrodynamic system consisting of a second stage combustor, a convergent nozzle, and a channel. The simulation uses an Argonne integral combustion flow computer code and another Argonne channel computer code to predict flow, thermal and electric properties in the seed particle laden reacting flow in the system. The combustion code is a general hydrodynamics computer code for two-phase, two-dimensional, turbulent, and reacting flows, based on mass, momentum, and energy conservation laws for gaseous and condensed phases. The channel code is a multigrid three-dimensional computer code for compressible flow subject to magnetic and electric interactions. Results of this study suggests that (1) the processes of seed particle evaporation, seed vapor dispersion, and gas ionization in the reacting flow are critical to the evaluation of the downstream channel performance and (2) particle size, loading, and inlet profile have strong effects on wall deposition and plasma temperature development.

  4. Dispersion of seed vapor and gas ionization in an MHD second stage combustor and channel

    SciTech Connect (OSTI)

    Chang, S.L.; Lottes, S.A.; Bouillard, J.X.

    1992-07-01

    An approach is introduced for the simulation of a magnetohydrodynamic system consisting of a second stage combustor, a convergent nozzle, and a channel. The simulation uses an Argonne integral combustion flow computer code and another Argonne channel computer code to predict flow, thermal and electric properties in the seed particle laden reacting flow in the system. The combustion code is a general hydrodynamics computer code for two-phase, two-dimensional, turbulent, and reacting flows, based on mass, momentum, and energy conservation laws for gaseous and condensed phases. The channel code is a multigrid three-dimensional computer code for compressible flow subject to magnetic and electric interactions. Results of this study suggests that (1) the processes of seed particle evaporation, seed vapor dispersion, and gas ionization in the reacting flow are critical to the evaluation of the downstream channel performance and (2) particle size, loading, and inlet profile have strong effects on wall deposition and plasma temperature development.

  5. Elbow mass flow meter

    DOE Patents [OSTI]

    McFarland, Andrew R.; Rodgers, John C.; Ortiz, Carlos A.; Nelson, David C.

    1994-01-01

    Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

  6. A compact neutron generator using a field ionization source

    SciTech Connect (OSTI)

    Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali; Schenkel, Thomas

    2011-10-31

    Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-#12;bers promise the high #12;eld-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of #12;field emitters with a density up to 10{sup 6} tips/cm{sup 2} and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.

  7. Ionization Branching Ratio Control with a Resonance Attosecond Clock

    SciTech Connect (OSTI)

    Argenti, Luca; Lindroth, Eva

    2010-07-30

    We investigate the possibility to monitor the dynamics of autoionizing states in real-time and control the yields of different ionization channels in helium by simulating extreme ultraviolet (XUV) pump IR-probe experiments focused on the N=2 threshold. The XUV pulse creates a coherent superposition of doubly excited states which is found to decay by ejecting electrons in bursts. Prominent interference fringes in the photoelectron angular distribution of the 2s and 2p ionization channels are observed, along with significant out-of-phase quantum beats in the yields of the corresponding parent ions.

  8. New directions in optical atomic spectrometry

    SciTech Connect (OSTI)

    de Galan, L.

    1986-05-01

    Soon after its invention a successful method of analysis goes through a phase of rapid growth and exaggerated expectations before it recedes to a more balanced position in the analytical domain. Flame and furnace atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES), as we know them now, were introduced 20 to 30 years ago, developed into commercial instruments within a decade after their first description in the scientific literature, and have now reached a state of developmental equilibrium. It is undeniable that these techniques have continued to develop, but recent advances have been largely technical and cosmetic. The emphasis on automation and software has made life much easier and has significantly reduced the demand for manpower, but it has not enlarged the analytical scope of the techniques. Many initial promises have been fulfilled, but some shortcomings persist even today. At this point it would be easy to formulate the ideal method that determines all elements from the sub-parts-per-billion level to the 100% level, simultaneously, with high precision and accuracy, and at minimal cost. Clearly, no single method can possibly match such unrealistic expectations. In this article the author has, therefore, chosen the more modest approach of identifying some weak points in available technology and analyzing possible remedies. In several cases current developments are reviewed, and novel instruments proposed in the literature are evaluated. In other cases, the problems have hardly been addressed and thus may pose a challenge for future research. 10 references, 6 tables.

  9. A theoretical study of acoustic glitches in low-mass main-sequence stars

    SciTech Connect (OSTI)

    Verma, Kuldeep; Antia, H. M.; Basu, Sarbani; Mazumdar, Anwesh E-mail: antia@tifr.res.in E-mail: anwesh@tifr.res.in

    2014-10-20

    There are regions in stars, such as ionization zones and the interface between radiative and convective regions, that cause a localized sharp variation in the sound speed. These are known as 'acoustic glitches'. Acoustic glitches leave their signatures on the oscillation frequencies of stars, and hence these signatures can be used as diagnostics of these regions. In particular, the signatures of these glitches can be used as diagnostics for the position of the second helium ionization zone and that of the base of the envelope convection zone. With the help of stellar models, we study the properties of these acoustic glitches in main-sequence stars. We find that the acoustic glitch due to the helium ionization zone does not correspond to the dip in the adiabatic index ?{sub 1} caused by the ionization of He II, but to the peak in ?{sub 1} between the He I and He II ionization zones. We find that it is easiest to study the acoustic glitch that is due to the helium ionization zone in stars with masses in the range 0.9-1.2 M {sub ?}.

  10. Numerical modeling of laser tunneling ionization in explicit particle-in-cell codes

    SciTech Connect (OSTI)

    Chen, M.; Cormier-Michel, E.; Geddes, C.G.R.; Bruhwiler, D.L.; Yu, L.L.; Esarey, E.; Schroeder, C.B.; Leemans, W.P.

    2013-03-01

    Methods for the calculation of laser tunneling ionization in explicit particle-in-cell codes used for modeling laserplasma interactions are compared and validated against theoretical predictions. Improved accuracy is obtained by using the direct current form for the ionization rate. Multi level ionization in a single time step and energy conservation have been considered during the ionization process. The effects of grid resolution and number of macro-particles per cell are examined. Implementation of the ionization algorithm in two different particle-in-cell codes is compared for the case of ionization-based electron injection in a laserplasma accelerator.

  11. Linear electronic field time-of-flight ion mass spectrometers

    DOE Patents [OSTI]

    Funsten, Herbert O. (Los Alamos, NM)

    2010-08-24

    Time-of-flight mass spectrometer comprising a first drift region and a second drift region enclosed within an evacuation chamber; a means of introducing an analyte of interest into the first drift region; a pulsed ionization source which produces molecular ions from said analyte of interest; a first foil positioned between the first drift region and the second drift region, which dissociates said molecular ions into constituent atomic ions and emits secondary electrons; an electrode which produces secondary electrons upon contact with a constituent atomic ion in second drift region; a stop detector comprising a first ion detection region and a second ion detection region; and a timing means connected to the pulsed ionization source, to the first ion detection region, and to the second ion detection region.

  12. Ultra-Sensitive Measurements of 233U by Accelerator Mass Spectrometry for National Security Applications.

    SciTech Connect (OSTI)

    Tumey, S J; Brown, T A; Buchholz, B A; Hamilton, T F; Hutcheon, I D; Williams, R W

    2009-07-13

    By making modifications to our previously established measurement setup, we increased our abundance sensitivity for {sup 233}U by three orders of magnitude and can now measure {sup 233}U/{sup 238}U ratios as low as 10{sup -13}. Because {sup 233}U has separate production pathways than {sup 236}U, it can provide valuable information on the particular source of anthropogenic uranium in a sample. We demonstrated the utility of our improved capability by using {sup 233}U to distinguish separate sources of anthropogenic uranium in a set of samples collected from a contaminated site. In the future, we plan to apply our new capability to characterizing {sup 233}U in a wide range of uranium materials.

  13. Kinetics of laser pulse vaporization of uranium dioxide by mass spectrometry

    SciTech Connect (OSTI)

    Tsai, C.

    1981-11-01

    Safety analyses of nuclear reactors require knowledge of the evaporation behavior of UO/sub 2/ at temperatures well above the melting point of 3140 K. In this study, rapid transient heating of a small spot on a UO/sub 2/ specimen was accomplished by a laser pulse, which generates a surface temperature excursion. This in turn vaporizes the target surface and the gas expands into vacuum. The surface temperature transient was monitored by a fast-response automatic optical pyrometer. The maximum surface temperatures investigated range from approx. 3700 K to approx. 4300 K. A computer program was developed to simulate the laser heating process and calculate the surface temperature evolution. The effect of the uncertainties of the high temperature material properties on the calculation was included in a sensitivity study for UO/sub 2/ vaporization. The measured surface temperatures were in satisfactory agreements.

  14. Accelerator Mass Spectrometry | U.S. DOE Office of Science (SC...

    Office of Science (SC) Website

    ... An important application of AMS measurements of the naturally occurring 36ClCl ratio in water (as opposed to the one created by atmospheric and underground nuclear weapons test) ...

  15. Demountable direct injection high efficiency nebulizer for inductively coupled plasma mass spectrometry

    DOE Patents [OSTI]

    Montaser, Akbar; Westphal, Craig S.; Kahen, Kaveh; Rutkowski, William F.; Acon, Billy W.

    2006-12-05

    A nebulizer adapted for adjusting a position of a capillary tube contained within the nebulizer is provided. The nebulizer includes an elongated tubular shell having a gas input port and a gas output port, a capillary adjustment adapter for displacing the capillary tube in a lateral direction via a rotational force, and a connector for connecting the elongated tubular shell, the capillary adjustment adapter and the capillary tube.

  16. Analysis of Interstitial Elements in Niobium with Secondary Ion Mass Spectrometry (SIMS)

    SciTech Connect (OSTI)

    Maheshwari, P.; Griffis, D. P.; Stevie, F. A.; Myeneni, G.; Ciovati, G.; Rigsbee, J. M.

    2011-03-31

    Superconducting Radio Frequency (SRF) cavities provide enhanced efficiency and reduced energy utilization in present day particle accelerators. Niobium (Nb) is the material of choice for these cavities due to its high critical temperature and critical magnetic field. In order to understand why certain treatments, especially a low temperature bake, improve performance, it is important to study Nb surface characteristics and identify elemental contamination that can affect the performance of the cavity. H, C, O, and N are of interest because they are interstitial impurities in Nb. In earlier work, SIMS analysis using a CAMECA IMS-6F with Cs{sup +} primary beam showed that C and N were probably not significant factors impacting performance but there was a very high level of H in the Nb. Ion implants of C, N, O, and D into Nb provided quantification of C, N, O and indicated that D is very mobile in the Nb. Further analyses showed that heat treated Nb has lower levels of surface H than non heat treated Nb and subsequent removal of surface oxide by etching causes intake of H in a heat treated Nb sample. This result helps confirm the role of surface oxide as a hydrogen barrier. To further understand the oxide, Nb samples were anodized to obtain a thicker surface oxide and H and D were implanted into this oxide to check for the appearance of implant peaks. SIMS depth profile analyses were carried out and confirmed the presence of the implant shape for these elements in the oxide. Relative Sensitivity Factor (RSFs) could then be calculated for quantification of H in the oxide. Since the Nb matrix signal showed little change from the oxide to the substrate, the same RSF was used to estimate the H concentration in the Nb at 2x10{sup 22} atoms/cm{sup 3}(approximately 40% mole fraction H).

  17. Extending the frontiers of mass spectrometric instrumentation and methods

    SciTech Connect (OSTI)

    Schieffer, Gregg

    2010-12-15

    The focus of this dissertation is two-fold: developing novel analysis methods using mass spectrometry and the implementation and characterization of a novel ion mobility mass spectrometry instrumentation. The novel mass spectrometry combines ion trap for ion/ion reactions coupled to an ion mobility cell. The long term goal of this instrumentation is to use ion/ion reactions to probe the structure of gas phase biomolecule ions. The three ion source - ion trap - ion mobility - qTOF mass spectrometer (IT - IM - TOF MS) instrument is described. The analysis of the degradation products in coal (Chapter 2) and the imaging plant metabolites (Appendix III) fall under the methods development category. These projects use existing commercial instrumentation (JEOL AccuTOF MS and Thermo Finnigan LCQ IT, respectively) for the mass analysis of the degraded coal products and the plant metabolites, respectively. The coal degradation paper discusses the use of the DART ion source for fast and easy sample analysis. The sample preparation consisted of a simple 50 fold dilution of the soluble coal products in water and placing the liquid in front of the heated gas stream. This is the first time the DART ion source has been used for analysis of coal. Steven Raders under the guidance of John Verkade came up with the coal degradation projects. Raders performed the coal degradation reactions, worked up the products, and sent them to me. Gregg Schieffer developed the method and wrote the paper demonstrating the use of the DART ion source for the fast and easy sample analysis. The plant metabolite imaging project extends the use of colloidal graphite as a sample coating for atmospheric pressure LDI. DC Perdian and I closely worked together to make this project work. Perdian focused on building the LDI setup whereas Schieffer focused on the MSn analysis of the metabolites. Both Perdian and I took the data featured in the paper. Perdian was the primary writer of the paper and used it as a

  18. High resolution resonance ionization imaging detector and method

    DOE Patents [OSTI]

    Winefordner, James D.; Matveev, Oleg I.; Smith, Benjamin W.

    1999-01-01

    A resonance ionization imaging device (RIID) and method for imaging objects using the RIID are provided, the RIID system including a RIID cell containing an ionizable vapor including monoisotopic atoms or molecules, the cell being positioned to intercept scattered radiation of a resonance wavelength .lambda..sub.1 from the object which is to be detected or imaged, a laser source disposed to illuminate the RIID cell with laser radiation having a wavelength .lambda..sub.2 or wavelengths .lambda..sub.2, .lambda..sub.3 selected to ionize atoms in the cell that are in an excited state by virtue of having absorbed the scattered resonance laser radiation, and a luminescent screen at the back surface of the RIID cell which presents an image of the number and position of charged particles present in the RIID cell as a result of the ionization of the excited state atoms. The method of the invention further includes the step of initially illuminating the object to be detected or imaged with a laser having a wavelength selected such that the object will scatter laser radiation having the resonance wavelength .lambda..sub.1.

  19. Ionization monitor with improved ultra-high megohm resistor

    DOE Patents [OSTI]

    Burgess, Edward T.

    1988-11-05

    An ionization monitor measures extremely small currents using a resistor containing a beta emitter to generate ion-pairs which are collected as current when the device is used as a feedback resistor in an electrometer circuit. By varying the amount of beta emitter, the resistance of the resistor may be varied.

  20. Method and apparatuses for ion cyclotron spectrometry

    DOE Patents [OSTI]

    Dahl, David A.; Scott, Jill R.; McJunkin, Timothy R.

    2012-03-06

    An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber. The trapping electric field may comprise a field potential that, when taken in cross-section along the z-axis, includes at least one section that is concave down and at least one section that is concave up so that ions traversing the field potential experience a net magnetron effect on a cyclotron frequency of the ions that is substantially equal to zero. Other apparatuses and a method for performing ion cyclotron spectrometry are also disclosed herein.

  1. Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −}

    SciTech Connect (OSTI)

    Cox, Richard M; Kim, JungSoo; Armentrout, P. B. E-mail: mheaven@emory.edu; Bartlett, Joshua; VanGundy, Robert A.; Heaven, Michael C. E-mail: mheaven@emory.edu; Ard, Shaun G.; Shuman, Nicholas S.; Viggiano, Albert A. E-mail: mheaven@emory.edu; Melko, Joshua J.

    2015-04-07

    The exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −} has been re-evaluated through the combination of several experimental methods. The thermal reactivity (300–650 K) of Sm{sup +} and SmO{sup +} with a range of species measured using a selected ion flow tube-mass spectrometer apparatus is reported and provides limits for the bond strength of SmO{sup +}, 5.661 eV ≤ D{sub 0}(Sm{sup +}-O) ≤ 6.500 eV. A more precise value is measured to be 5.72{sub 5} ± 0.07 eV, bracketed by the observed reactivity of Sm{sup +} and SmO{sup +} with several species using a guided ion beam tandem mass spectrometer (GIBMS). Combined with the established Sm ionization energy (IE), this value indicates an exothermicity of the title reaction of 0.08 ± 0.07 eV, ∼0.2 eV smaller than previous determinations. In addition, the ionization energy of SmO has been measured by resonantly enhanced two-photon ionization and pulsed-field ionization zero kinetic energy photoelectron spectroscopy to be 5.7427 ± 0.0006 eV, significantly higher than the literature value. Combined with literature bond energies of SmO, this value indicates an exothermicity of the title reaction of 0.14 ± 0.17 eV, independent from and in agreement with the GIBMS result presented here. The evaluated thermochemistry also suggests that D{sub 0}(SmO) = 5.83 ± 0.07 eV, consistent with but more precise than the literature values. Implications of these results for interpretation of chemical release experiments in the thermosphere are discussed.

  2. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOE Patents [OSTI]

    Reilly, Peter T. A. [Knoxville, TN

    2010-12-14

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  3. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOE Patents [OSTI]

    Reilly, Peter T.A.

    2013-12-03

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  4. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOE Patents [OSTI]

    Reilly, Peter T.A.

    2014-05-13

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  5. The Origins of Mass

    SciTech Connect (OSTI)

    Lincoln, Don

    2014-07-30

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  6. The Origins of Mass

    ScienceCinema (OSTI)

    Lincoln, Don

    2014-08-07

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  7. Elbow mass flow meter

    DOE Patents [OSTI]

    McFarland, A.R.; Rodgers, J.C.; Ortiz, C.A.; Nelson, D.C.

    1994-08-16

    The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity. 3 figs.

  8. In Silico Identification Software (ISIS): A Machine Learning Approach to Tandem Mass Spectral Identification of Lipids

    SciTech Connect (OSTI)

    Kangas, Lars J.; Metz, Thomas O.; Isaac, Georgis; Schrom, Brian T.; Ginovska-Pangovska, Bojana; Wang, Luning; Tan, Li; Lewis, Robert R.; Miller, John H.

    2012-05-15

    Liquid chromatography-mass spectrometry-based metabolomics has gained importance in the life sciences, yet it is not supported by software tools for high throughput identification of metabolites based on their fragmentation spectra. An algorithm (ISIS: in silico identification software) and its implementation are presented and show great promise in generating in silico spectra of lipids for the purpose of structural identification. Instead of using chemical reaction rate equations or rules-based fragmentation libraries, the algorithm uses machine learning to find accurate bond cleavage rates in a mass spectrometer employing collision-induced dissocia-tion tandem mass spectrometry. A preliminary test of the algorithm with 45 lipids from a subset of lipid classes shows both high sensitivity and specificity.

  9. Method of trivalent chromium concentration determination by atomic spectrometry

    DOE Patents [OSTI]

    Reheulishvili, Aleksandre N.; Tsibakhashvili, Neli Ya.

    2006-12-12

    A method is disclosed for determining the concentration of trivalent chromium Cr(III) in a sample. The addition of perchloric acid has been found to increase the atomic chromium spectrometric signal due to Cr(III), while leaving the signal due to hexavalent chromium Cr(VI) unchanged. This enables determination of the Cr(III) concentration without pre-concentration or pre-separation from chromium of other valences. The Cr(III) concentration may be measured using atomic absorption spectrometry, atomic emission spectrometry or atomic fluorescence spectrometry.

  10. Design and Performance of a High-Flux Electrospray Ionization Source for Ion Soft-Landing

    SciTech Connect (OSTI)

    Gunaratne, Kalupathirannehelage Don D.; Prabhakaran, Venkateshkumar; Ibrahim, Yehia M.; Norheim, Randolph V.; Johnson, Grant E.; Laskin, Julia

    2015-01-01

    We report the design and evaluation of a new high-intensity electrospray ionization source for ion soft-landing experiments. The source incorporates a dual ion funnel, which enables operation with a higher gas load through an expanded heated inlet into the additional first region of differential pumping. This capability allowed us to examine the effect of the inner diameter (ID) of the heated stainless steel inlet on the total ion current transmitted through the dual funnel interface and, more importantly, the mass-selected ion current delivered to the deposition target. The ion transmission of the dual funnel is similar to the transmission of the single funnel used in our previous soft landing studies. However, substantially higher ion currents were obtained using larger ID heated inlets and an orthogonal inlet geometry, in which the heated inlet is positioned perpendicular to the direction of ion propagation through the instrument. The highest ion currents were obtained using the orthogonal geometry and a 1.4 mm ID heated inlet. The corresponding stable deposition rate of ~1 μg of mass-selected ions per day will facilitate future studies focused on the controlled deposition of biological molecules on substrates and preparation of materials for studies in catalysis, energy storage, and self-assembly

  11. Absolute beam emittance measurements at RHIC using ionization profile monitors

    SciTech Connect (OSTI)

    Minty, M.; Connolly, R; Liu, C.; Summers, T.; Tepikian, S.

    2014-08-15

    In the past, comparisons between emittance measurements obtained using ionization profile monitors, Vernier scans (using as input the measured rates from the zero degree counters, or ZDCs), the polarimeters and the Schottky detectors evidenced significant variations of up to 100%. In this report we present studies of the RHIC ionization profile monitors (IPMs). After identifying and correcting for two systematic instrumental errors in the beam size measurements, we present experimental results showing that the remaining dominant error in beam emittance measurements at RHIC using the IPMs was imprecise knowledge of the local beta functions. After removal of the systematic errors and implementation of measured beta functions, precise emittance measurements result. Also, consistency between the emittances measured by the IPMs and those derived from the ZDCs was demonstrated.

  12. Electron- and proton-induced ionization of pyrimidine

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Champion, Christophe; Quinto, Michele; Weck, Philippe F

    2015-03-27

    This present work describes a quantum-mechanically based model of the electron- and proton-induced ionization of isolated pyrimidine molecules. The impact energies range from the target ionization threshold up to ~1 keV for electrons and from 10 keV up to 10 MeV for protons. The cross-section calculations are performed within the 1st Born approximation in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered projectiles are both described by plane waves. The pyrimidine target is described using the Gaussian 09 software package. Furthermore, our theoretical predictions obtained are in good agreement with experimental absolutemore » total cross sections, while large discrepancies are observed between existing semi-empirical models and the present calculations.« less

  13. Electron- and proton-induced ionization of pyrimidine

    SciTech Connect (OSTI)

    Champion, Christophe; Quinto, Michele; Weck, Philippe F

    2015-03-27

    This present work describes a quantum-mechanically based model of the electron- and proton-induced ionization of isolated pyrimidine molecules. The impact energies range from the target ionization threshold up to ~1 keV for electrons and from 10 keV up to 10 MeV for protons. The cross-section calculations are performed within the 1st Born approximation in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered projectiles are both described by plane waves. The pyrimidine target is described using the Gaussian 09 software package. Furthermore, our theoretical predictions obtained are in good agreement with experimental absolute total cross sections, while large discrepancies are observed between existing semi-empirical models and the present calculations.

  14. Ionization of ethane, butane, and octane in strong laser fields

    SciTech Connect (OSTI)

    Palaniyappan, Sasi; Mitchell, Rob; Ekanayake, N.; Watts, A. M.; White, S. L.; Sauer, Rob; Howard, L. E.; Videtto, M.; Mancuso, C.; Wells, S. J.; Stanev, T.; Wen, B. L.; Decamp, M. F.; Walker, B. C.

    2010-10-15

    Strong-field photoionization of ethane, butane, and octane are reported at intensities from 10{sup 14} to 10{sup 17} W/cm{sup 2}. The molecular fragment ions, C{sup +} and C{sup 2+}, are created in an intensity window from 10{sup 14} to 10{sup 15} W/cm{sup 2} and have intensity-dependent yields similar to the molecular fragments C{sub m}H{sub n}{sup +} and C{sub m}H{sub n}{sup 2+}. In the case of C{sup +}, the yield is independent of the molecular parent chain length. The ionization of more tightly bound valence electrons in carbon (C{sup 3+} and C{sup 4+}) has at least two contributing mechanisms, one influenced by the parent molecule size and one resulting from the tunneling ionization of the carbon ion.

  15. INTERACTION OF MUON BEAM WITH PLASMA DEVELOPED DURING IONIZATION COOLING

    SciTech Connect (OSTI)

    S. Ahmed, D. Kaplan, T. Roberts, L. Spentzouris, K. Beard

    2012-07-01

    Particle-in-cell simulations involving the interaction of muon beam (peak density 10{sup 18} m{sup 3}) with Li plasma (ionized medium) of density 10{sup 16}-10{sup 22} m{sup -3} have been performed. This study aimed to understand the effects of plasma on an incoming beam in order to explore scenario developed during the process of ionization cooling. The computer code takes into account the self-consistent electromagnetic effects of beam interacting with plasma. This study shows that the beam can pass through the plasma of densities four order of magnitude higher than its peak density. The low density plasmas are wiped out by the beam, however, the resonance is observed for densities of similar order. Study reveals the signature of plasma wakefield acceleration.

  16. Ionization-Induced Electron Trapping inUltrarelativistic Plasma Wakes

    SciTech Connect (OSTI)

    Oz, E.; Deng, S.; Katsouleas, T.; Muggli, P.; Barnes, C.D.; Blumenfeld, I.; Decker, F.J.; Emma, P.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.; Krejcik, P.; O'Connell, C.; Siemann, R.H.; Walz, D.; Auerbach, D.; Clayton, C.E.; Huang, C.; Johnson, D.K.; Joshi, C.; /UCLA

    2007-04-06

    The onset of trapping of electrons born inside a highly relativistic, 3D beam-driven plasma wake is investigated. Trapping occurs in the transition regions of a Li plasma confined by He gas. Li plasma electrons support the wake, and higher ionization potential He atoms are ionized as the beam is focused by Li ions and can be trapped. As the wake amplitude is increased, the onset of trapping is observed. Some electrons gain up to 7.6 GeV in a 30.5 cm plasma. The experimentally inferred trapping threshold is at a wake amplitude of 36 GV/m, in good agreement with an analytical model and PIC simulations.

  17. Propagation direction reversal of ionization zones in the transition between high and low current magnetron sputtering

    SciTech Connect (OSTI)

    School of Materials Science and Engineering, State Key Lab for Materials Processing and Die & Mold Technology, Huazhong University of Science and Technology, Wuhan 430074, China; Department of Physics, University of California Berkeley, Berkeley, California 94720, USA; Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA; Yang, Yuchen; Liu, Jason; Liu, Lin; Anders, Andr

    2014-12-11

    Past research has revealed the propagation of dense, asymmetric ionization zones in both high and low current magnetron discharges. Here we report about the direction reversal of ionization zone propagation as observed with fast cameras. At high currents, zones move in the E B direction with velocities of 103 to 104 m/s. However at lower currents, ionization zones are observed to move in the opposite, the -E B direction, with velocities ~;; 103 m/s. It is proposed that the direction reversal is associated with the local balance of ionization and supply of neutrals in the ionization zone.

  18. Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research facilities investigated charge-transfer processes and subsequent ion fragmentation dynamics in nanoclusters

  19. Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research facilities investigated charge-transfer processes and subsequent ion fragmentation dynamics in nanoclusters

  20. Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Site-Selective Ionization in Nanoclusters Affects Subsequent Fragmentation Print Understanding charge-transfer processes at the atomic level of nanoscale systems is of the utmost importance for designing nanodevices based on quantum-dot structures, nanotubes, or two-dimensional graphene sheets. Researchers from Western Michigan University, Berkeley Lab, and other international research facilities investigated charge-transfer processes and subsequent ion fragmentation dynamics in nanoclusters