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Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

High-Resolution Desorption Electrospray Ionization Mass Spectrometry for Chemical Characterization of Organic Aerosols  

SciTech Connect (OSTI)

Characterization of the chemical composition and chemical transformations of secondary organic aerosol (SOA) is both a major challenge and the area of greatest uncertainty in current aerosol research. This study presents the first application of desorption electrospray ionization combined with high-resolution mass spectrometry (DESI-MS) for detailed chemical characterization and studies of chemical aging of OA collected on Teflon substrates. DESI-MS offers unique advantages both for detailed characterization of chemically labile components in OA that cannot be detected using more traditional electrospray ionization mass spectrometry (ESI-MS) and for studying chemical aging of OA. DESI-MS enables rapid characterization of OA samples collected on substrates by eliminating the sample preparation stage. In addition, it enables detection and structural characterization of chemically labile molecules in OA samples by minimizing the residence time of analyte in the solvent. SOA produced by the ozonolysis of limonene (LSOA) was allowed to react with gaseous ammonia. Chemical aging resulted in measurable changes in the optical properties of LSOA observed using UV- visible spectroscopy. DESI-MS combined with tandem mass spectrometry experiments (MS/MS) enabled identification of species in aged LSOA responsible for absorption of the visible light. Detailed analysis of the experimental data allowed us to identify chemical changes induced by reactions of LSOA constituents with ammonia and distinguish between different mechanisms of chemical aging.

Laskin, Julia; Laskin, Alexander; Roach, Patrick J.; Slysz, Gordon W.; Anderson, Gordon A.; Nizkorodov, Serguei; Bones, David L.; Nguyen, Lucas

2010-03-01T23:59:59.000Z

2

Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors.  

SciTech Connect (OSTI)

Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurement using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 16 and K325, requires backbone motion to bring the reactive atoms into sufficient proximity for cross-linking. Evidence from other studies suggests that residues around K325 for a region of high backbone mobility. These findings show that cross-linking studies can provide insight into the structural dynamics of membrane proteins in their native environment.

Haskins, William E.; Leavell, Michael D.; Lane, Pamela; Jacobsen, Richard B.; Hong, Joohee; Ayson, Marites J.; Wood, Nichole L.; Schoeniger, Joseph S.; Kruppa, Gary Hermann; Sale, Kenneth L.; Young, Malin M.; Novak, Petr

2005-03-01T23:59:59.000Z

3

Picoelectrospray Ionization Mass Spectrometry Using Narrow-bore Chemically Etched Emitters  

SciTech Connect (OSTI)

Electrospray ionization mass spectrometry (ESI-MS) at flow rates below ~10 nL/min has been only sporadically explored due to difficulty in reproducibly fabricating emitters that can operate at lower flow rates. Here we demonstrate narrow orifice chemically etched emitters for stable electrospray at flow rates as low as 400 pL/min. Depending on the analyte concentration, we observe two types of MS signal response as a function of flow rate. At low concentrations, an optimum flow rate is observed slightly above 1 nL/min, while the signal decreases monotonically with decreasing flow rates at higher concentrations. In spite of lower MS signal, the ion utilization efficiency increases exponentially with decreasing flow rate in all cases. No unimolecular response was observed within this flow rate range during the analysis of an equimolar mixture of peptides, indicating that ionization efficiency is an analyte-dependent characteristic in given experimental conditions. While little to no gain in signal-to-noise was achieved at ultralow flow rates for concentration-limited analyses, experiments consuming the same amount of analyte suggest that mass-limited analyses will benefit strongly from the use of low flow rates and avoiding unnecessary sample dilution. By operating under optimal conditions, consumption of just 500 zmol of sample yielded signal-to-noise ratios ~10 for some peptides. These findings have important implications for the analysis of trace biological samples.

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

2014-01-01T23:59:59.000Z

4

Gas Chromatography -Mass Spectrometry  

E-Print Network [OSTI]

GCMS - 1 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS OF ETHANOL AND BENZENE IN GASOLINE Last updated: June 17, 2014 #12;GCMS - 2 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS). The goal of this experiment is to separate the components in a sample of gasoline using Gas Chromatography

Nizkorodov, Sergey

5

A study of the tropospheric oxidation of volatile organic compounds using chemical ionization mass spectrometry  

E-Print Network [OSTI]

The mechanisms and kinetics of reactions important to the troposphere have been investigated using a high pressure, turbulent, discharge-flow technique coupled to a chemical ionization mass spectrometer. The ability to ...

Broekhuizen, Keith Edward, 1974-

2002-01-01T23:59:59.000Z

6

Determination of naphthenic acids in California crudes and refinery waste waters by fluoride ion chemical ionization mass spectrometry  

SciTech Connect (OSTI)

A method based on negative ion chemical ionization mass spectrometry using fluoride (F/sup -/) ions produced from NF/sub 3/ reagent gas has been applied to the analysis of naphthenic acids in California crude oils and refinery waste waters. Since complex mixtures of naphthenic acids cannot be separated into individual components, only the determination of relative distribution of acids classified by the hydrogen deficiency was possible. The identities and relative distribution of paraffinic and mono-, di-, tri, and higher polycyclic acids were obtained from the intensities of the carboxylate (RCOO/sup -/) ions.

Dzidic, I.; Somerville, A.C.; Raia, J.C.; Hart, H.V.

1988-07-01T23:59:59.000Z

7

THE EARLY DAYS OF ACCELERATOR MASS SPECTROMETRY  

E-Print Network [OSTI]

reported work in high energy mass spectrometry-two in 1938,importance of high energy mass spectrometry was demonstrated

Alvarez, L.W.

2010-01-01T23:59:59.000Z

8

Chemical Analysis of Complex Organic Mixtures Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Reactive nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was utilized for the analysis of secondary organic aerosol produced through ozonolysis of limonene (LSOA). Previous studies showed that LSOA constituents are multifunctional compounds containing aldehyde and ketone groups. In this study, we used the selectivity of the Girard T (GT) reagent towards carbonyl compounds to examine the utility of reactive nano-DESI for the analysis of complex organic mixtures. In these experiments, 1-100 {micro}M GT solution was used as a working solvent for reactive nano-DESI analysis. Abundant products of a single addition of GT to LSOA constituents were observed at GT concentrations in excess of 10 {micro}M. We found that LSOA compounds with 18-20 carbon atoms (dimers) and 27-30 carbon atoms (trimers) react with GT through a simple addition reaction resulting in formation of the carbinolamine derivative. In contrast, reactions of GT with monomeric species result in formation of both the carbinolamine and the hydrazone derivatives. In addition, several monomers did not react with GT on the timescale of our experiment. These molecules were characterized by relatively high values of the double bond equivalent (DBE) and low oxygen content. Furthermore, because addition of a charged GT tag to a neutral molecule eliminates the discrimination against the low proton affinity compounds in the ionization process, reactive nano-DESI analysis enables quantification of individual compounds in the complex mixture. For example, we were able to estimate for the first time the amounts of dimers and trimers in the LSOA mixture. Specifically, we found that the most abundant LSOA dimer was detected at ca. 0.5 pg level and the total amount of dimers and trimers in the analyzed sample was just around 11 pg. Our results indicate that reactive nano-DESI is a valuable approach for examining the presence of specific functional groups and quantification of compounds possessing these groups in complex mixtures.

Laskin, Julia; Eckert, Peter A.; Roach, Patrick J.; Heath, Brandi S.; Nizkorodov, Sergey A.; Laskin, Alexander

2012-08-21T23:59:59.000Z

9

High-Resolution Desorption Electrospray Ionization Mass Spectrometry for Chemical Characterization  

E-Print Network [OSTI]

, University of California-Irvine, Irvine, California 92697 Characterization of the chemical composition solar radiation and modifications of cloud properties.1-6 The extent of radiative forcing and cloud

Nizkorodov, Sergey

10

Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: Insighs into particle origin and chemistry  

SciTech Connect (OSTI)

Knowledge of the spatially-resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry, understanding particle reactivity and the potential environmental impact. We demonstrate the application of nanometer-scale secondary ion mass spectrometry (Cameca NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as the sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad of range of particle sizes. We have used this technique to probe spatially resolved composition of ambient particles collected during a field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth resolved chemical imaging in ambient particle research. 1 Particles examined in this study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location prior to the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen and chlorine at the particle surface. The observed surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas-particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insights into their chemical history.

Ghosal, Sutapa; Weber, Peter K.; Laskin, Alexander

2014-04-21T23:59:59.000Z

11

Application of coincidence ion mass spectrometry for chemical and structural analysis at the sub-micron scale  

E-Print Network [OSTI]

Surfaces can be probed with a variant of secondary ion mass spectrometry (SIMS) where the bombardment is with a sequence of single keV projectiles, each resolved in time and space, coupled with the separate record of the secondary ions (SIs) ejected...

Balderas, Sara

2005-11-01T23:59:59.000Z

12

Facilities: NHMFL 9.4 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Citation: Atmospheric Pressure Laser-Induced Acoustic Desorption Chemical Ionization Mass Spectrometry  

E-Print Network [OSTI]

. Rodgers, & Alan G. Marshall, Analytical Chemistry 84, 7131-7137 (2012). Figure 1. Schematic diagram hydrocarbons (the primary components of gasoline) are difficult to analyze by mass spectrometry, because

Weston, Ken

13

Linear electric field mass spectrometry  

DOE Patents [OSTI]

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.

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

1992-12-01T23:59:59.000Z

14

Symposium on accelerator mass spectrometry  

SciTech Connect (OSTI)

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.

None

1981-01-01T23:59:59.000Z

15

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

SciTech Connect (OSTI)

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.

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

2012-02-07T23:59:59.000Z

16

Single Cell Analysis Using Microfluidics Coupled to Ultrasensitive Mass Spectrometry  

E-Print Network [OSTI]

Single Cell Analysis Using Microfluidics Coupled to Ultrasensitive Mass Spectrometry PI Ryan Kelly is to combine microfluidic sample preparation and separations with the ultrasensitive mass spectrometry (MS without the need for chemical labeling. We will combine our expertise in the fields of microfluidics

17

Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

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.

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

2014-06-13T23:59:59.000Z

18

Mass Spectrometry | EMSL  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region serviceMissionreal-time informationScience &MapsMarketsMass

19

Identification of Protein-Protein Interactions and Topologies in Living Cells with Chemical Cross-linking and Mass Spectrometry  

SciTech Connect (OSTI)

We present results from a novel strategy that enables concurrent identification of protein-protein interactions and topologies in living cells without specific antibodies or genetic manipulations for immuno/affinity purifications. The strategy consists of: (i) chemical cross-linking reaction: intact cell labeling with a novel class of chemical cross-linkers, protein interaction reporters (PIRs); (ii) two-stage mass spectrometric analysis: stage 1 identification of PIR-labeled proteins and construction of a restricted database by 2D-LC/MS/MS; and stage 2 analysis of PIR-labeled peptides by multiplexed LC/FTICR-MS; (iii) data analysis: identification of cross-linked peptides and proteins of origin using accurate mass and other constraints. The primary advantage of the PIR approach and distinction from current technology is that protein interactions together with topologies are detected in native biological systems by stabilizing protein complexes with new covalent bonds while the proteins are present in the original cellular environment. Thus, weak or transient interactions or interactions that require properly folded, localized, or membrane-bound proteins can be labeled and identified through the PIR approach. This strategy was applied to S. oneidensis bacterial cells and initial studies resulted in identification of a set of protein-protein interactions and their contact/binding regions. Furthermore, most identified interactions involved membrane proteins, suggesting the PIR approach is particularly suited for studies of membrane protein-protein interactions, an area under-represented with current widely-used approaches.

Zhang, Haizhen; Tang, Xiaoting; Munske, Gerhard R.; Tolic, Nikola; Anderson, Gordon A.; Bruce, James E.

2009-03-01T23:59:59.000Z

20

Identification of protein-protein interaction and topologies in living cells by chemical cross-linking and mass spectrometry  

SciTech Connect (OSTI)

Current chemical cross-linking methods are commonly employed for mapping sites of interaction and three-dimensional structure in purified, known protein complexes. When applied in vivo in combination of co-immunoprecipitation methods, information on the sites of interaction between proteins are unattainable due to overwhelming sample complexity. We present results from a novel cross-linking strategy that allow simultaneous protein-protein interaction and surface topology measurement in vivo without any prior knowledge of the system. The strategy consists of: (i) cross-linking reaction: intact cell labeling with protein interaction reporters (PIRs); (ii) two-stage mass spectrometric analysis: stage 1 identification of PIR-labeled proteins and construction of a restricted database by 2D-LC/MS/MS; and stage 2 analysis of PIR-labeled peptides by multiplexed LC/FTICR-MS; (iii) data analysis: identification of cross-linked peptides and proteins of origin using accurate mass and other constraints. This strategy was applied to Shewanella oneidensis MR-1 bacterial cells and successfully identified a protein-protein interaction between SecA and a small outer membrane lipoprotein as well as their sites of interaction in vivo.

Zhang, Haizhen; Tang, Xiaoting; Munske, Gerhard R.; Tolic, Nikola; Anderson, Gordon A.; Bruce, James E.

2008-10-20T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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)

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.

Buratto, Steven K. [UC Santa Barbara

2013-09-03T23:59:59.000Z

22

Characterization of nonpolar lipids and steroids by using laser-induced acoustic desorption/chemical ionization, atmospheric pressure chemical ionization, and electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

Laser-induced acoustic desorption (LIAD) combined with ClMn(H{sub 2}O){sup +} chemical ionization (CI) was tested for the analysis of nonpolar lipids and selected steroids in a Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR). The nonpolar lipids studied, cholesterol, 5?-cholestane, cholesta-3,5-diene, squalene, and ?-carotene, were found to solely form the desired water replacement product (adduct-H{sub 2}O) upon reaction with the ClMn(H{sub 2}O){sup +} ions. The steroids, androsterone, dehydroepiandrosterone (DHEA), estrone, estradiol, and estriol, also form abundant adduct-H{sub 2}O ions, but less abundant adduct-2H{sub 2}O ions were also observed. Neither (+)APCI nor (+)ESI can ionize the saturated hydrocarbon lipid, cholestane. APCI successfully ionizes the unsaturated hydrocarbon lipids to form exclusively the intact protonated analytes. However, it causes extensive fragmentation for cholesterol and the steroids. The worst case is cholesterol that does not produce any stable protonated molecules. On the other hand, ESI cannot ionize any of the hydrocarbon analytes, saturated or unsaturated. However, ESI can be used to protonate the oxygen-containing analytes with substantially less fragmentation than for APCI in all cases except for cholesterol and estrone. In conclusion, LIAD/ClMn(H{sub 2}O){sup +} chemical ionization is superior over APCI and ESI for the mass spectrometric characterization of underivatized nonpolar lipids and steroids.

Jin, Z.; Daiya, S.; Kenttämaa, Hilkka I.

2011-01-01T23:59:59.000Z

23

Thermal Decomposition of Molecules Relevant to Combustion and Chemical Vapor Deposition by Flash Pyrolysis Time-of-Flight Mass Spectrometry  

E-Print Network [OSTI]

of Small Molecules by Flash Pyrolysis, University ofwas performed using flash pyrolysis vacuum-ultraviolet time-Vapor Deposition by Flash Pyrolysis Time-of-Flight Mass

Lemieux, Jessy Mario

2013-01-01T23:59:59.000Z

24

accurate mass spectrometry: Topics by E-print Network  

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

Positive Negative *) Atomic composition Graham, Nick 2 FOCUS: TOP-DOWN MASS SPECTROMETRY Collective Mass Spectrometry Approaches Biology and Medicine Websites Summary:...

25

Atmospheric Solids Analysis Probe Mass Spectrometry: A New Approach...  

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

Atmospheric Solids Analysis Probe Mass Spectrometry: A New Approach for Airborne Particle Analysis. Atmospheric Solids Analysis Probe Mass Spectrometry: A New Approach for Airborne...

26

New Mass Spectrometry Techniques for Studying Physical Chemistry...  

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

Mass Spectrometry Techniques for Studying Physical Chemistry of Atmospheric Heterogeneous Processes. New Mass Spectrometry Techniques for Studying Physical Chemistry of Atmospheric...

27

Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams  

SciTech Connect (OSTI)

High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification.

Debord, J. Daniel; Smith, Donald F.; Anderton, Christopher R.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana; Gomer, Richard H.; Fernandez-Lima, Francisco A.

2014-06-09T23:59:59.000Z

28

Methods for recalibration of mass spectrometry data  

DOE Patents [OSTI]

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.

Tolmachev, Aleksey V. (Richland, WA); Smith, Richard D. (Richland, WA)

2009-03-03T23:59:59.000Z

29

High performance ˛?˛Cf plasma desorption mass spectrometry  

E-Print Network [OSTI]

ABSTRACT . ACKNOWLEDGEMENT TABLE OF CONTENTS . tv LIST OF TABLES LIST OF FIGURES C~R I. INTRODUCTION tx xt A. A General Overview . 1. Particle-Induced Desorption 2. The Application of Cf PDMS in Analytical Chemistry 3. Time-of-Flight Mass... INTRODUCTION The method of 'Cf plasma desorption mass spectrometry (PDMS) is a mass spectrometric method pioneered in 1974 by Macfarlane and co-workers (1) at Texas A&M University. This method uses fission fragments (highly energetic atomic ions...

McIntire, Thomas Shane

1991-01-01T23:59:59.000Z

30

accuracy mass spectrometry: Topics by E-print Network  

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

Milos 2 High Mass Accuracy and High Mass Resolving Power FT-ICR Secondary Ion Mass Spectrometry for Biological Tissue Imaging CERN Preprints Summary: Biological tissue imaging by...

31

Optimization Of A Mass Spectrometry Process  

SciTech Connect (OSTI)

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.

Lopes, Jose [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1, 1959-007 Lisbon (Portugal); Instituto Superior Tecnico, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Instituto Tecnologico e Nuclear, E.N. 10, Sacavem 2686-953 (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Alegria, F. Correa [Instituto Superior Tecnico, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Instituto de Telecomunicacoes, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Redondo, Luis [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1, 1959-007 Lisbon (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Barradas, N. P.; Alves, E. [Instituto Tecnologico e Nuclear, E.N. 10, Sacavem 2686-953 (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Rocha, Jorge [Instituto Tecnologico e Nuclear, E.N. 10, Sacavem 2686-953 (Portugal)

2011-06-01T23:59:59.000Z

32

Correlation of rocket propulsion fuel properties with chemical composition using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry followed by partial least squares regression analysis  

SciTech Connect (OSTI)

There is an increased need to more fully assess and control the composition of kerosene based rocket propulsion fuels, namely RP-1 and RP-2. In particular, it is crucial to be able to make better quantitative connections between the following three attributes: (a) fuel performance, (b) fuel properties (flash point, density, kinematic viscosity, net heat of combustion, hydrogen content, etc) and (c) the chemical composition of a given fuel (i.e., specific chemical compounds and compound classes present as a result of feedstock blending and processing). Indeed, recent efforts in predicting fuel performance through modeling put greater emphasis on detailed and accurate fuel properties and fuel compositional information. In this regard, advanced distillation curve (ADC) metrology provides improved data relative to classical boiling point and volatility curve techniques. Using ADC metrology, data obtained from RP-1 and RP-2 fuels provides compositional variation information that is directly relevant to predictive modeling of fuel performance. Often, in such studies, one-dimensional gas chromatography (GC) combined with mass spectrometry (MS) is typically employed to provide chemical composition information. Building on approaches using GC-MS, but to glean substantially more chemical composition information from these complex fuels, we have recently studied the use of comprehensive two dimensional gas chromatography combined with time-of-flight mass spectrometry (GC × GC - TOFMS) to provide chemical composition data that is significantly richer than that provided by GC-MS methods. In this report, by applying multivariate data analysis techniques, referred to as chemometrics, we are able to readily model (correlate) the chemical compositional information from RP-1 and RP-2 fuels provided using GC × GC - TOFMS, to the fuel property information such as that provided by the ADC method and other specification properties. We anticipate that this new chemical analysis strategy will have broad implications for the development of high fidelity composition-property models, leading to an optimized approach to fuel formulation and specification for advanced engine cycles.

Kehimkar, Benjamin; Hoggard, Jamin C.; Marney, Luke C.; Billingsley, Matthew; Fraga, Carlos G.; Bruno, Thomas J.; Synovec, Robert E.

2014-01-31T23:59:59.000Z

33

applying mass spectrometry: Topics by E-print Network  

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

*) Atomic composition Graham, Nick 4 Analytical Performance of Accelerator Mass Spectrometry and Liquid Scintillation Counting for Biotechnology Websites Summary: Analytical...

34

Development of Advanced Optics and High Resolution Instrumentation for Mass Spectrometry Based Proteomics  

E-Print Network [OSTI]

Imaging mass spectrometry (MS) analysis allows scientists the ability to obtain spatial and chemical information of analytes on a wide variety of surfaces. The ability to image biological analytes is an important tool in many areas of life science...

Sherrod, Stacy D.

2010-01-14T23:59:59.000Z

35

ablation mass spectrometry: Topics by E-print Network  

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

and laser ablation electrospray ionization mass Chemistry Websites Summary: -mass spectrometry (DESI-MS) and laser ablation electrospray ionization-MS (LAESI-MS) were used to...

36

Monolithic multinozzle emitters for nanoelectrospray mass spectrometry  

DOE Patents [OSTI]

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.

Wang, Daojing (Daly City, CA); Yang, Peidong (Kensington, CA); Kim, Woong (Seoul, KR); Fan, Rong (Pasadena, CA)

2011-09-20T23:59:59.000Z

37

Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzitane (CL-20)  

SciTech Connect (OSTI)

Hexanitrohexaazaisowurtzitane, (C6H6N12O12, MW 438) {CL-20}, is a high-energy propellent that has been recently developed and successfully tested (Nielsen et al. 1998). CL-20 releases more energy on ignition and is more stable to accidental detonation than currently used energetic materials. It is expected to replace many of the energetic materials currently being used by the Department of Defense (DoD). The EPA method 8330 (EPA 1997) for the analysis of explosives and metabolites in soils calls for the use of UV/Vis detection. High performance liquid chromatography has been used to quantify CL-20 and precursor concentration (Bazaki et al. 1998`) at relatively high concentrations. Fourier transform infrared (FTIR) spectroscopy has been used to identify different crystal forms of CL-20 (4 isomers; Kim et al. 1998). Campbell et al. (1997) utilized particle beam mass spectrometry for the analysis of enzymatic degradation of explosives. Introduction and recent improvements of ionization techniques such as electrospray (ES) have allowed the mass spectrometer to become more widely used in liquid chromatography. Schilling(1996) also examined explosive components and metabolites using electrospray (ES) and atmospheric pressure chemical ionization (APCI) liquid chromatography/mass spectrometry (LC/MS). Schilling’s results showed that compared to thermospray LC/MS, APCI and ES were more sensitive than thermospray by at least an order of magnitude. 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 10 nitroso-RDX metabolites, and other munitions in ground water have been analyzed using solid phase extraction and isotope dilution liquid chromatography-APCI mass spectrometry (Cassada et al. 1999). The method detection limits indicate that nitramine and nitroaromatic compounds can be routinely determined in ground water samples using electrospray LC/MS with concentration techniques utilizing solid-phase extraction. Miller et al. (1996) studied nitrated explosives with mobile phase additives to enhance the ESI intensities and spectral consistencies. Several of the explosives gave nitrate adduct ions in the negative mode with ammonium nitrate as the mobile phase. The nitramines RDX and 1,3,5,7-tetranitro-1,3,5,7 tetraazacyclooctane (HMX) showed the greatest enhancement in response of the explosives. Ammonium nitrate was used as the mobile phase and made it possible to obtain consistent and interpretable LC/MS spectra at the nanogram level. Campbell et al. (1999), Shi et al. (2000), and Goheen et al. (1999) utilized electrospray ionization mass spectrometry for the identification of degradation products of explosives. Yinon et al. (1997) used ESI and tandem mass spectrometry collision-induced dissociation to examine several nitramine compounds including trinitrotolutene (TNT), RDX, and pentaerythritol tetranitrate (PETN). The results indicate that explosives can be detected in the negative ion mode and characterized by various adduct ions. As an example, for nitroglycerin, the major adduct ion observed was (M+ONO2)-. In addition, Harvey et al. (1992) have used direct probe mass spectrometry for the analysis of degradation products of tetryl and its transformation products in soil. The negative ion electrospray mass spectrum of CL-20 is reported here. The major adduct ions observed under negative ion conditions were (M+Cl)- at m/z 473 and (M+ONO2) – at m/z 500. In addition, the results of mass spectrometry/mass spectrometry studies are also discussed.

Campbell, James A.; Szecsody, Jim E.; Devary, Brooks J.; Valenzuela, Blandina R.

2007-09-03T23:59:59.000Z

38

ambient mass spectrometry: Topics by E-print Network  

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

and Applications of Liquid Sample Desorption Electrospray Ionization Mass Spectrometry (DESI-MS). Open Access Theses and Dissertations Summary: ?? This dissertation...

39

analytical mass spectrometry: Topics by E-print Network  

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

analytical methods for solving a variety of molecular structure problems. Among high. Extension of mass spectrometry to the analysis of high molecular weight materials,...

40

aerosol mass spectrometry: Topics by E-print Network  

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

analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry MIT - DSpace Summary: Four hydroxynitrates (R(OH)R'ONO2) representative of...

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

High-Resolution Electrospray Ionization Mass Spectrometry Analysis...  

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

Mass Spectrometry Analysis of Water- Soluble Organic Aerosols Collected with a Particle Abstract: This work demonstrates the utility of a particle-into-liquid sampler (PILS) a...

42

Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry  

SciTech Connect (OSTI)

Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics.

Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

2011-06-16T23:59:59.000Z

43

RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2004; 18: 27062712  

E-Print Network [OSTI]

mass spectrometry.7,8 The internal energy that ions acquire in the MALDI process or via colli- sional of high quality. Tandem mass spectrometry utilizing photodissociation (PD) with ultraviolet (UV) radiation be a viable alternative to CAD for tandem mass spectrometry of large molecules because the energy requirement

Kim, Myung Soo

44

Digital microfluidic sample preparation for biological mass spectrometry   

E-Print Network [OSTI]

The use of mass spectrometry in the biosciences has undergone huge growth in re- cent years due to sustained effort in the development of new ionisation techniques, more powerful mass analysers and better bioinformatic ...

Stokes, Adam A.

2011-06-27T23:59:59.000Z

45

Secondary ion mass spectrometry (SIMS)! Seminar 4 (UN)!  

E-Print Network [OSTI]

for compositional analysis of solid surfaces and thin films. When a surface is bombarded by high energy beam! ! Secondary ion mass spectrometry (SIMS)! Seminar 4 (UN)! ! ! ! ! ! ! ! ! Author: Nina Kovacic! ___________________________________________________________________________! ABSTRACT! ! Secondary ion mass spectrometry (SIMS) is an analytical experimental technique, used

Â?umer, Slobodan

46

Mass-sensitive chemical preconcentrator  

DOE Patents [OSTI]

A microfabricated mass-sensitive chemical preconcentrator actively measures the mass of a sample on an acoustic microbalance during the collection process. The microbalance comprises a chemically sensitive interface for collecting the sample thereon and an acoustic-based physical transducer that provides an electrical output that is proportional to the mass of the collected sample. The acoustic microbalance preferably comprises a pivot plate resonator. A resistive heating element can be disposed on the chemically sensitive interface to rapidly heat and release the collected sample for further analysis. Therefore, the mass-sensitive chemical preconcentrator can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

Manginell, Ronald P. (Albuquerque, NM); Adkins, Douglas R. (Albuquerque, NM); Lewis, Patrick R. (Albuquerque, NM)

2007-01-30T23:59:59.000Z

47

Analytical Performance of Accelerator Mass Spectrometry and Liquid Scintillation Counting for  

E-Print Network [OSTI]

Analytical Performance of Accelerator Mass Spectrometry and Liquid Scintillation Counting for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California of California, San Francisco, California 94143 Accelerator mass spectrometry (AMS) has been applied

Hammock, Bruce D.

48

Evaluation of histone sequence and modifications by electrospray ionization mass spectrometry and tandem mass spectrometry  

SciTech Connect (OSTI)

The histones, together with other specialized proteins and DNA, form the extraordinarily complex structure of chromatin. Electrospray ionization (ESI) permits the promotion of such protein species into the gas phase as intact, multiply charged molecular species. Mass spectrometry (MS), using a linear quadrupole mass filter, permits measurement of the relative molecular mass of these intact species with precision and accuracy. The latter are sufficient to evaluate variations in the primary structure of the histones and the type and extent of the natural and induced multiple covalent modifications. The locations of modifications are revealed by tandem mass spectrometry using tandem linear quadrupole or ion trap instruments on the intact species or the modified peptides derived by selective proteolysis. Experiments in applying this technique to histones from K562, a human-derived cell line, have demonstrated variations in the profile of modification through the normal cell cycle and in the presence of agents that inhibit enzymes responsible for reversal of the modification. The authors are currently testing the hypothesis that ESI-MS will permit the sensitive and selective identification of insult-induced modifications, distinguishing them from natural cell-cycle changes. This will be possible because ESI-MS reveals the full details of the profile of multiple posttranslational modifications of histones.

Edmonds, C.G.; Loo, J.A.; Smith, R.D.; Fuciarelli, A.F.; Thrall, B.D.; Morris, J.E.; Springer, D.L. (Pacific Northwest Lab., Richland, WA (United States))

1993-01-01T23:59:59.000Z

49

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

SciTech Connect (OSTI)

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.

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

2000-05-01T23:59:59.000Z

50

Mass Spectrometry-based Methods for Phosphorylation Site Mapping of  

E-Print Network [OSTI]

Mass Spectrometry-based Methods for Phosphorylation Site Mapping of Hyperphosphorylated Proteins spectrometry-based approach. No one approach was able to identify all phosphopeptides in the tryptic digests and detected by scintillation counting or autoradiography. The HPLC fraction or excised TLC spot is subjected

Shou, Wenying

51

Toward Plasma Proteome Profiling with Ion Mobility-Mass Spectrometry  

E-Print Network [OSTI]

Toward Plasma Proteome Profiling with Ion Mobility-Mass Spectrometry Stephen J. Valentine, Manolo D) analysis of a plasma digest sample where abundant proteins have not been removed. Protein database searches- for comparative plasma profiling studies. Keywords: ion mobility spectrometry · proteome profiling

Clemmer, David E.

52

Process diagnostics and thickness metrology using in situ mass spectrometry for the chemical vapor deposition of W from H2 WF6  

E-Print Network [OSTI]

response time 4 s sensor system sampled gas directly from a commercial Ulvac ERA-1000 reactor in order wafers, at 67 Pa 0.5 Torr total pressure, and for wafer temperatures around 400 °C. A relatively fast An ideal real-time chemical sensor for monitoring pro- cesses involving multicomponent gas mixtures would

Gougousi, Theodosia

53

Accelerator mass spectrometry: from nuclear physics to dating  

SciTech Connect (OSTI)

The discussion reviews the use of accelerators originally intended for nuclear physics to do high resolution mass spectrometry for the purpose of isotope dating and age estimation of materials. (GHT)

Kutschera, W.

1982-01-01T23:59:59.000Z

54

Molecular Beam Mass Spectrometry (MBMS) (Revised) (Fact Sheet)  

SciTech Connect (OSTI)

This fact sheet provides information about Molecular Beam Mass Spectrometry (MBMS) capabilities and applications at NREL's National Bioenergy Center. NREL has six MBMS systems that researchers and industry partners can use to understand thermochemical biomass conversion and biomass composition recalcitrance.

Not Available

2011-07-01T23:59:59.000Z

55

accelerator mass spectrometry: Topics by E-print Network  

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

Bousfield, George R. 2004-05-01 25 High performance ?Cf plasma desorption mass spectrometry Texas A&M University - TxSpace Summary: Track and the Dissemination of Energy. . ....

56

Tools for investigating cellular signaling networks by mass spectrometry  

E-Print Network [OSTI]

Mass spectrometry has become the tool of choice for proteomics. Its unrivaled coverage and reproducibility has positioned it head and shoulders above competing techniques for analyzing protein expression post-translational ...

Curran, Timothy Gordon

2014-01-01T23:59:59.000Z

57

RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2005; 19: 32483252  

E-Print Network [OSTI]

to be that photofragment ions generated at this wavelength are similar to those from low- and high-energy CAD, and are thusRAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2005; 19: 3248 of singly protonated peptides at 193 nm investigated with tandem time-of-flight mass spectrometry Jeong Hee

Kim, Myung Soo

58

RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2005; 19: 24812487  

E-Print Network [OSTI]

chromophore dissociated efficiently when a suf- ficiently high laser pulse energy was used. Also, the pulseRAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2005; 19: 2481 time-of- flight (TOF) mass spectrometry of ions generated by matrix-assisted laser desorption

Kim, Myung Soo

59

Subcellular analysis by laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

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.

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

2014-12-02T23:59:59.000Z

60

Facilitation of protein 3-D structure determination using enhanced peptide amide deuterium exchange mass spectrometry (DXMS)  

E-Print Network [OSTI]

and Energy Change at High Resolution Employing Enhanced Peptide Amide Deuterium Exchange- Mass Spectrometry (

Pantazatos, Dennis Peter

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Determination of the stellar (n,$\\gamma$) cross section of $^{54}Fe$ with accelerator mass spectrometry  

E-Print Network [OSTI]

Determination of the stellar (n,$\\gamma$) cross section of $^{54}Fe$ with accelerator mass spectrometry

Coquard, L; Dillmann, I; Wallner, A; Knie, K; Kutschera, W

2006-01-01T23:59:59.000Z

62

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)

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.

Perdian, David C.

2009-08-19T23:59:59.000Z

63

Laser desorption mass spectrometry for fast DNA analysis  

SciTech Connect (OSTI)

During the past few years, major effort has been directed toward developing mass spectrometry to measure biopolymers because of the great potential benefit to biomedical research. Hellenkamp and his co-workers were the first to report that large polypeptide molecules can be ionized and detected without significant fragmentation when a greater number of nicotinic acid molecules are used as a matrix. This method is now well known as matrix-assisted laser desorption/ionization (MALDI). Since then, various groups have reported measurements of very large proteins by MALDI. Reliable protein analysis by MALDI is more or less well established. However, the application of MALDI to nucleic acids analysis has been found to be much more difficult. Most research on the measurement of nucleic acid by MALDI were stimulated by the Human Genome Project. Up to now, the only method for reliable routine analysis of nucleic acid is gel electrophoresis. Different sizes of nucleic acids can be separated in gel medium when a high electric field is applied to the gel. However, the time needed to separate different sizes of DNA segments usually takes from several minutes to several hours. If MALDI can be successfully used for nucleic acids analysis, the analysis time can be reduced to less than I millisecond. In addition, no tagging with radioactive materials or chemical dyes is needed. In this work, we will review recent progress related to MALDI for DNA analysis.

Chen, C.H.; Ch`ang, L.Y.; Taranenko, N.I.; Allman, S.L.; Tang, K.; Matteson, K.J.

1995-09-01T23:59:59.000Z

64

Matrix Effects in Biological Mass Spectrometry Imaging: Identification and Compensation  

SciTech Connect (OSTI)

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.

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

2014-07-21T23:59:59.000Z

65

Coming to a hospital near you: mass spectrometry imaging  

SciTech Connect (OSTI)

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.

Bowen, Ben

2013-10-31T23:59:59.000Z

66

Coming to a hospital near you: mass spectrometry imaging  

ScienceCinema (OSTI)

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.

Bowen, Ben

2014-06-24T23:59:59.000Z

67

Transition of Iodine Analysis to Accelerator Mass Spectrometry  

SciTech Connect (OSTI)

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 fundamental mechanisms of ionization in the AMS system and which produces a beneficial cleanup of molecular interferences. Continued clean operation of the extraction process was demonstrated through blank analysis included with all sample sets analyzed. INL work showed improvement on the first year’s demonstration of AMS vs. TIMS. An improved extraction of high volume air filters followed by isotopic analysis by AMS, can be used successfully to make iodine measurements with results comparable to those obtained by filter combustion and TIMS analysis. More progress on the conversion from an extract solution to an AMS sample ready for analysis is still needed. Although the preparation scheme through AMS is already at a higher performing thoughput than TIMS, the chemical preparation cannot match the instrument capability for number of samples per day without further development.

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

2012-09-01T23:59:59.000Z

68

Absorption Mode FT-ICR Mass Spectrometry Imaging  

SciTech Connect (OSTI)

Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O'Connor, Peter B.; Heeren, Ronald M.

2013-12-03T23:59:59.000Z

69

Mass spectrometry of proteins of known mass Andrew D. Miranker*  

E-Print Network [OSTI]

deter- mination has two significant advantages. First, the mass accuracy under these conditions to the orifice of the mass analyzer. As a result, there is a local separation of charges at the tip

Miranker, Andrew

70

Time-of-flight secondary ion mass spectrometry with transmission of energetic primary cluster ions through foil targets  

SciTech Connect (OSTI)

We developed time-of-flight (TOF) secondary ion (SI) mass spectrometry that provides informative SI ion mass spectra without needing a sophisticated ion beam pulsing system. In the newly developed spectrometry, energetic large cluster ions with energies of the order of sub MeV or greater are used as primary ions. Because their impacts on the target surface produce high yields of SIs, the resulting SI mass spectra are informative. In addition, the start signals necessary for timing information on primary ion incidence are provided by the detection signals of particles emitted from the rear surface of foil targets upon transmission of the primary ions. This configuration allows us to obtain positive and negative TOF SI mass spectra without pulsing system, which requires precise control of the primary ions to give the spectra with good mass resolution. We also successfully applied the TOF SI mass spectrometry with energetic cluster ion impacts to the chemical structure characterization of organic thin film targets.

Hirata, K., E-mail: k.hirata@aist.go.jp [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Saitoh, Y.; Chiba, A.; Yamada, K.; Matoba, S.; Narumi, K. [Takasaki Advanced Radiation Research Institute (TARRI), Japan Atomic Energy Agency (JAEA), Takasaki, Gumma 370-1292 (Japan)] [Takasaki Advanced Radiation Research Institute (TARRI), Japan Atomic Energy Agency (JAEA), Takasaki, Gumma 370-1292 (Japan)

2014-03-15T23:59:59.000Z

71

Tandem Mass Spectrometry identifies many mouse brain O-GlcNAcylated...  

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

Tandem Mass Spectrometry identifies many mouse brain O-GlcNAcylated proteins including EGF domain-specific O-GlcNAc transferase Tandem Mass Spectrometry identifies many mouse brain...

72

Small system for tritium accelerator mass spectrometry  

DOE Patents [OSTI]

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.

Roberts, Mark L. (Livermore, CA); Davis, Jay C. (Livermore, CA)

1993-01-01T23:59:59.000Z

73

Small system for tritium accelerator mass spectrometry  

DOE Patents [OSTI]

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.

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

1993-02-23T23:59:59.000Z

74

Chip-Scale Quadrupole Mass Filters for Portable Mass Spectrometry  

E-Print Network [OSTI]

We report the design, fabrication, and characterization of a new class of chip-scale quadrupole mass filter (QMF). The devices are completely batch fabricated using a wafer-scale process that integrates the quadrupole ...

Cheung, Kerry

75

Charge Prediction of Lipid Fragments in Mass Spectrometry  

SciTech Connect (OSTI)

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.

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

2011-12-18T23:59:59.000Z

76

Tissue Imaging Using Nanospray Desorption Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

We present the first results showing the ambient imaging of biological samples in their native environment using nanospray desorption ionization (nanoDESI) mass spectrometry. NanoDESI is an ambient pressure ionization technique that enables precise control of ionization of molecules from substrates. We demonstrate highly sensitive and robust analysis of tissue samples with high spatial resolution (<12 {mu}m) without sample preparation, which will be essential for applications in clinical diagnostics, drug discovery, molecular biology, and biochemistry.

Laskin, Julia; Heath, Brandi S.; Roach, Patrick J.; Cazares, Lisa H.; Semmes, O. John

2012-01-03T23:59:59.000Z

77

JOURNAL OF MASS SPECTROMETRY J. Mass Spectrom. 2003; 38: 277282  

E-Print Network [OSTI]

tandem mass spectrom- etry even isomerizations such as isoaspartate formation are detectable.3 Low-energy, nuclear and endosomal morphology, a defect in fluid-phase uptake and an impairment in normal cytokinesis.1.02 derived from acrylamide-modified peptides.8 These fragmentation reactions can be utilized for the spe-

Manstein, Dietmar J.

78

Fourier transform mass spectrometry of high-mass biomolecules  

SciTech Connect (OSTI)

In this report the authors present an overview of the use of FTMS for the analysis of large biomolecules, with emphasis on recent developments in coupling ESI and MALDI with FTMS. A simple description of the principles of FTMS operation and experimental factors that are relevant to the examination of large molecules are also presented. The examples represent state-of-the-art capabilities of FTMS. On the basis of early reports, it is apparent that the applications of FTMS for the analysis of biopolymers will expand rapidly in the near future. Although many different types of mass analyzers are compatible with FAB, ESI, and MALDI, FTMS has exhibited particular potential for high sensitivity, accurate mass measurement, high-mass resolution, and structural characterization of large biopolymers. The recent results obtained with both ESI-FTMS and MALDI-FTMS are very exciting with respect to both fundamental advances in the capabilities of FTMS and potential applications in the biochemical laboratory. 63 refs., 6 figs., 1 tab.

Buchanan, M.V.; Hettich, R.L. (Oak Ridge National Lab., TN (United States))

1993-03-01T23:59:59.000Z

79

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

SciTech Connect (OSTI)

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. Multiple vacuum box locations may be set-up to supply several ICP-MS units with purified sample fractions such that a high sample throughput may be achieved, while still allowing for rapid measurement of short-lived actinides by alpha spectrometry.

Maxwell, S.; Jones, V.

2009-05-27T23:59:59.000Z

80

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

SciTech Connect (OSTI)

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.

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

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Future Directions of Structural Mass Spectrometry using Hydroxyl Radical Footprinting  

SciTech Connect (OSTI)

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-driven structural mass spectrometry experiments.

J Kiselar; M Chance

2011-12-31T23:59:59.000Z

82

Development of A Cryogenic Drift Cell Spectrometer and Methods for Improving the Analytical Figures of Merit for Ion Mobility-Mass Spectrometry Analysis  

E-Print Network [OSTI]

A cryogenic (325-80 K) ion mobility-mass spectrometer was designed and constructed in order to improve the analytical figures-of-merit for the chemical analysis of small mass analytes using ion mobility-mass spectrometry. The instrument incorporates...

May, Jody C.

2010-10-12T23:59:59.000Z

83

Fission Yield Measurements by Inductively Coupled Plasma Mass-Spectrometry  

SciTech Connect (OSTI)

Correct prediction of the fission products inventory in irradiated nuclear fuels is essential for accurate estimation of fuel burnup, establishing proper requirements for spent fuel transportation and storage, materials accountability and nuclear forensics. Such prediction is impossible without accurate knowledge of neutron induced fission yields. Unfortunately, the accuracy of the fission yields reported in the ENDF/B-VII.0 library is not uniform across all of the data and much of the improvement is desired for certain isotopes and fission products. We discuss our measurements of cumulative fission yields in nuclear fuels irradiated in thermal and fast reactor spectra using Inductively Coupled Plasma Mass Spectrometry.

Irina Glagolenko; Bruce Hilton; Jeffrey Giglio; Daniel Cummings; Karl Grimm; Richard McKnight

2009-11-01T23:59:59.000Z

84

Mass Spectrometry imaging of plant metabolites | The Ames Laboratory  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces andMapping the Nanoscale Landscape PrintSurveyMary K.MassSpectrometry

85

atomic mass spectrometry: Topics by E-print Network  

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

Negative *) Atomic composition Graham, Nick 3 Prospects in Analytical Atomic Spectrometry CERN Preprints Summary: Tendencies in five main branches of atomic spectrometry...

86

New developments in biochemical mass spectrometry: Electrospray ionization  

SciTech Connect (OSTI)

The principles, development, and recent application of electrospray ionization-mass spectrometry (ESI-MS) to biological compounds are reviewed. ESI-MS methods now allow determination of accurate molecular weights for proteins extending to over 50,000, and in some cases well over 100,000. Similar capabilities are being developed for oligonucleotides. The instrumentation used for ESI-MS is briefly described and it is shown that, although ionization efficiency appears to be uniformly high, detector sensitivity may be directly correlated with molecular weight. The use of tandem mass spectrometry (e.g., MS/MS) for extending collision-induced dissociation (CID) methods to the structural studies of large molecules is described. For example, effective CID of various albumin species (molecular weight {approximately}66,000) can be obtained, far larger than obtainable for singly charged molecular ions. The combination of capillary electrophoresis, in both free solution zone electrophoresis and isotachophoresis formats, as well as microcolumn liquid chromatography with ESI-MS, provides the capability for on-line separation and analysis of subpicomole quantities of proteins. These and other new developments related to ESI-MS are illustrated by a range of examples. Fundamental considerations suggest even more impressive developments may be anticipated related to detection sensitivity and methods for obtaining structural information.

Smith, R.D.; Loo, J.A.; Edmonds, C.G.; Barinaga, C.J.; Udseth, H.R. (Pacific Northwest Laboratory, Richland, WA (USA))

1990-05-01T23:59:59.000Z

87

Molecular Characterization of Organic Aerosols Using Nanospray Desorption/Electrospray Ionization-Mass Spectrometry  

SciTech Connect (OSTI)

Nanospray desorption electrospray ionization (Nano-DESI) combined with high-resolution mass spectrometry (HR/MS) is a promising approach for detailed chemical characterization of atmospheric organic aerosol (OA) collected in laboratory and field experiments. In Nano-DESI analyte is desorbed into a solvent bridge formed between two capillaries and the analysis surface, which enables fast and efficient characterization of OA collected on substrates without special sample preparation. Stable signals achieved using Nano-DESI make it possible to obtain high-quality HR/MS data using only a small amount of material (<10 ng). Furthermore, Nano-DESI enables efficient detection of chemically labile compounds in OA, which is important for understanding chemical aging phenomena.

Roach, Patrick J.; Laskin, Julia; Laskin, Alexander

2010-10-01T23:59:59.000Z

88

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)

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 fuel compacts across a burnup range of approximately 10 to 20 % FIMA and also validate the approach used in the physics simulation of the AGR 1 experiment.

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

2014-10-01T23:59:59.000Z

89

Detection of methoxylated anions of fullerenes by electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

Electrospray ionization mass spectrometry (ESI-MS) has been applied to the study of the reactions of fullerenes in solution. The C[sub 60][sup [minus

Wilson, S.R.; Wu, Y. (New York Univ., NY (United States))

1993-11-03T23:59:59.000Z

90

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

Office of Science (SC) Website

Mass Spectrometry at ANL and ORNL Developed at: Argonne National Laboratory (ANL), Oak Ridge National Laboratory (ORNL) Developed in: Current Result of NP research: Basic NP...

91

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

DOE Patents [OSTI]

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).

Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

2011-06-21T23:59:59.000Z

92

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

DOE Patents [OSTI]

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).

Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

2011-11-29T23:59:59.000Z

93

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

DOE Patents [OSTI]

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).

Vertes, Akos; Nemes, Peter

2014-08-19T23:59:59.000Z

94

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

DOE Patents [OSTI]

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).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

95

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

DOE Patents [OSTI]

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).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

96

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

DOE Patents [OSTI]

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).

Vertes, Akos; Nemes, Peter

2012-10-30T23:59:59.000Z

97

Method for predicting peptide detection in mass spectrometry  

DOE Patents [OSTI]

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.

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

2010-07-13T23:59:59.000Z

98

Ion Mobility SpectrometryMass Spectrometry Performance Using Electrodynamic Ion Funnels and Elevated Drift Gas Pressures  

SciTech Connect (OSTI)

The ability of ion mobility spectrometry coupled with mass spectrometry (IMS-MS) to characterize biological mixtures has been illustrated over the past eight years. However, the challenges posed by the extreme complexity of many biological samples have demonstrated the need for higher resolution IMS-MS measurements. We have developed a higher resolution ESI-IMS-TOF MS by utilizing high pressure electrodynamic ion funnels at both ends of the IMS drift cell and operating the drift cell at an elevated pressure compared to a previous design. The ESI-IMS-TOF MS instrument consists of an ESI source, an hourglass ion funnel used for ion accumulation/injection into an 88 cm drift cell followed by a 10 cm ion funnel and a commercial orthogonal time-of-flight mass spectrometer providing high mass measurement accuracy. It was found that the rear (exit) ion funnel could be effectively operated as an extension of the drift cell when the DC fields were matched, allowing the instrument to have an effective drift region of 98 cm. Two differentially pumped quadrupole regions were used to couple the IMS and TOF MS to focus and minimize the ion transient time between the stages. The resolution of the instrument was evaluated at pressures ranging from 4 to12 Torr and ion mobility drift voltages of 16 V/cm (4 Torr) to 43 V/cm (12 Torr). An increase in resolution from 55 to 80 was observed from 4 to 12 Torr nitrogen drift gas with no loss in sensitivity. Given the increased usage of ion funnels prior to ion mobility separations, additional attention was directed towards the influence of drift gas on the observed ion populations trapped and transmitted using an electrodynamic ion funnel. The choice of drift gas was shown to influence the degree of ion heating and relative trapping efficiency within the ion funnel.

Baker, Erin Shammel; Clowers, Brian H.; Li, Fumin; Tang, Keqi; Tolmachev, Aleksey V.; Prior, David C.; Belov, Mikhail E.; Smith, Richard D.

2007-06-28T23:59:59.000Z

99

Structural determination of intact proteins using mass spectrometry  

DOE Patents [OSTI]

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.

Kruppa, Gary (San Francisco, CA); Schoeniger, Joseph S. (Oakland, CA); Young, Malin M. (Livermore, CA)

2008-05-06T23:59:59.000Z

100

Low-level 14C measurements and Accelerator Mass Spectrometry  

SciTech Connect (OSTI)

Accelerator Mass Spectrometry (AMS) and isotope enrichment were used in 1991 to estimate that the 14C content of methane in natural gas was {<=}1.6x10-18 of the total carbon. The low content of 14C in underground hydrocarbons was verified later in the remarkable results from the Borexino test scintillation counter for solar neutrino studies. Since then studies of the 14C background problem have demonstrated that much of the background originally observed in the AMS measurements can, in principle, be eliminated. However, many difficulties and other backgrounds are to be faced as the limit for AMS is pushed still further towards possibly a ratio of < 10-21. These will be discussed.

Litherland, A.E.; Beukens, R.P.; Zhao, X.-L.; Kieser, W.E. [IsoTrace Laboratory, University of Toronto, Toronto, ON, M5S 1A7 (Canada); Gove, H.E. [IsoTrace Laboratory, University of Toronto, Toronto, ON, M5S 1A7 (Canada); Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627-0171 (United States)

2005-09-08T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Dating Studies of Elephant Tusks Using Accelerator Mass Spectrometry  

SciTech Connect (OSTI)

A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young animals.

Sideras-Haddad, E; Brown, T A

2002-10-03T23:59:59.000Z

102

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)

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.

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

2014-12-01T23:59:59.000Z

103

˛?˛Cf-plasma desorption mass spectrometry of RNA nucleosides  

E-Print Network [OSTI]

~ CH5 + CH3 CH3 + CH4 ~ C2H5 + H2 Proton or hydride transfer reactions of these secondary ions with the sample molecule produce the major portion of the CI mass spectra. Because the molecular ions are formed by these chemical reactions... low, and co'1'lisional deactivation between sample fons and air molecules results in a loss of intensity and resolution for the sample ions detected. -7 The vacuum in the mass spectrometer is maintained in the 10 16 torr region by a Sargent...

Piper, Duane Gilbert

1976-01-01T23:59:59.000Z

104

In situ characterization of GaN quantum dot growth with reflection high-energy electron diffraction and line-of-sight mass spectrometry  

E-Print Network [OSTI]

mass spectrometry and re?ection high-energy electronmass spectrometry ?QMS? and re?ection high-energy electron

Brown, J S; Koblmuller, G; Averbeck, R; Riechert, H; Speck, J S

2006-01-01T23:59:59.000Z

105

Ga adsorbate on (0001) GaN: In situ characterization with quadrupole mass spectrometry and reflection high-energy electron diffraction  

E-Print Network [OSTI]

mass spectrometry and re?ection high-energy electronmass spectrometry ?QMS? and re?ection high-energy electron

Brown, J S; Koblmuller, G; Wu, F; Averbeck, R; Riechert, H; Speck, J S

2006-01-01T23:59:59.000Z

106

NMIS With Gamma Spectrometry for Attributes of Pu and HEU, Explosives and Chemical Agents  

SciTech Connect (OSTI)

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.

Mihalczo, J. T.; Mattingly, J. K.; Mullens, J. A.; Neal, J. S.

2002-05-10T23:59:59.000Z

107

International Journal of Mass Spectrometry 288 (2009) 1621 Contents lists available at ScienceDirect  

E-Print Network [OSTI]

International Journal of Mass Spectrometry 288 (2009) 16­21 Contents lists available at ScienceDirect International Journal of Mass Spectrometry journal homepage: www.elsevier.com/locate/ijms Utility of reaction-MS2 and PD-MS3 were combined, demonstrating the utility of transient ion detection by PD-MS3

Kim, Myung Soo

108

International Journal of Mass Spectrometry 287 (2009) 105113 Contents lists available at ScienceDirect  

E-Print Network [OSTI]

to deposit more internal energy into these clusters, providing access to alternative, high energyInternational Journal of Mass Spectrometry 287 (2009) 105­113 Contents lists available at ScienceDirect International Journal of Mass Spectrometry journal homepage: www.elsevier.com/locate/ijms Influence of cluster

Wysocki, Vicki H.

109

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

E-Print Network [OSTI]

OpenMSI: A High-Performance Web-Based Platform for Mass Spectrometry Imaging Oliver RĂĽbel, AnnetteMSI: A High-Performance Web-Based Platform for Mass Spectrometry Imaging Oliver Rubel,* Annette Greiner. Acknowledgements: This work was supported by and used resources of the National Energy Research Scientific

110

JOURNAL OF MASS SPECTROMETRY, VOL. 31, 339-350 (1996) SPECIAL FEATURE  

E-Print Network [OSTI]

fragmentation mechanisms of protonated peptides is discussed and demonstrated. High internal energy deposition in understandingpeptide fragmentation by low-energy tandem mass spectrometry. KEYWORDS: surface-induced dissociationJOURNAL OF MASS SPECTROMETRY, VOL. 31, 339-350 (1996) SPECIAL FEATURE: PERSPECTIVE Surface

Wysocki, Vicki H.

111

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically  

E-Print Network [OSTI]

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551 is the suspected cause. The test involves ingestion of a physiological quantity of B12 labeled with gamma

California at Davis, University of

112

Explorations of Functionalized Gold Nanoparticle Surface Chemistry for Laser Desorption Ionization Mass Spectrometry Applications  

E-Print Network [OSTI]

EXPLORATIONS OF FUNCTIONALIZED GOLD NANOPARTICLE SURFACE CHEMISTRY FOR LASER DESORPTION IONIZATION MASS SPECTROMETRY APPLICATIONS A Thesis by MARIO ESTUARDO GOMEZ HERNANDEZ Submitted to the Office... DESORPTION IONIZATION MASS SPECTROMETRY APPLICATIONS A Thesis by MARIO ESTUARDO GOMEZ HERNANDEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree...

Gomez Hernandez, Mario 1980-

2012-07-11T23:59:59.000Z

113

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

SciTech Connect (OSTI)

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 equivalents. AMS provides an sensitive, accurate and precise method of measuring drug compounds in biological matrices.

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

2010-02-05T23:59:59.000Z

114

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

SciTech Connect (OSTI)

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'.

Williams, R W; Gaffney, A M

2012-04-18T23:59:59.000Z

115

Trace elements in coal by glow discharge mass spectrometry  

SciTech Connect (OSTI)

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.

Jacobs, M.L.; Wilson, C.R.; Pestovich, J. Jr. [WAL Inc., Wheat Ridge, CO (United States)] [and others

1995-08-01T23:59:59.000Z

116

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

SciTech Connect (OSTI)

A new ultra-high vacuum experiment is described that allows studying photo-induced chemical processes in interstellar ice analogues. MATRI{sup 2}CES - 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{sub 4}) 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{sub 4} 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.

Paardekooper, D. M., E-mail: dmpaardekooper@strw.leidenuniv.nl; Bossa, J.-B.; Isokoski, K.; Linnartz, H., E-mail: linnartz@strw.leidenuniv.nl [Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden (Netherlands)

2014-10-15T23:59:59.000Z

117

Prospects for large dynamic range isotope analysis using photon burst mass spectrometry  

SciTech Connect (OSTI)

Photon Burst Mass Spectrometry is a relatively new and untried method which may complement and extend the impressive achievements of Resonance Ionization Mass Spectrometry and Accelerator Mass Spectrometry in the field of large dynamic range isotope analysis. Theoretical predictions indicate that measurements in the 10/sup /minus/11/ to 10/sup /minus/15/ range are possible in a reasonable period of time with zero background. Experimentally only the very first demonstrations of PBMS with stable isotopes have been completed. 8 refs., 1 fig., 1 tab.

Fairbank, W.M. Jr.; LaBelle, R.D.; Keller, R.A.; Miller, C.M.; Poths, J.; Fearey, B.L.

1988-01-01T23:59:59.000Z

118

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)]

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.

Loh, N. Duane

119

A postsource decay study of bradykinin by Matrix-assisted laser desorption ionization mass spectrometry  

E-Print Network [OSTI]

Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry is a very powerful technique for the analysis of peptides and proteins. Fragmentation reactions of the protonated analyte molecule, [M+H]+ ions...

Wei, Xiaona

1996-01-01T23:59:59.000Z

120

The effect of solvent on matrix-assisted laser desorption ionization mass spectrometry  

E-Print Network [OSTI]

Since its introduction in 1988, matrix-assisted laser desorption/ionization mass spectrometry (MALDI) has developed into a useful analytical tool in the biological field. The work presented here focuses on the effect of solvent on MALDI ion yields...

Campo, Karen Kay

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Measurements of Volatile Organic Compounds Using Proton Transfer Reaction - Mass Spectrometry during the MILAGRO 2006 Campaign  

E-Print Network [OSTI]

Volatile organic compounds (VOCs) were measured by proton transfer reaction – mass spectrometry (PTR-MS) on a rooftop in the urban mixed residential and industrial area North Northeast of downtown Mexico City as part of ...

Fortner, E. C.

122

SwePep, a Database Designed for Endogenous Peptides and Mass Spectrometry*  

E-Print Network [OSTI]

SwePep, a Database Designed for Endogenous Peptides and Mass Spectrometry* Maria Fa¨ lth§, Karl Sko¨ ld§, Mathias Norrman, Marcus Svensson§, David Fenyo¨ , and Per E. Andren§** A new database, Swe the experimental peptide masses are compared with the peptide masses stored in the database both with and without

Chait, Brian T.

123

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

SciTech Connect (OSTI)

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.

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

2010-06-23T23:59:59.000Z

124

High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray Desorption Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Nanospray desorption electrospray ionization (nano-DESI) combined with tandem mass spectrometry (MS/MS), high-resolution mass analysis (m/m=17,500 at m/z 200), and rapid spectral acquisition enabled simultaneous imaging and identification of more than 300 molecules from 92 selected m/z windows (± 1 Da) with a spatial resolution of better than 150 um. Uterine sections of implantation sites on day 6 of pregnancy were analyzed in the ambient environment without any sample pre-treatment. MS/MS imaging was performed by scanning the sample under the nano-DESI probe at 10 um/s while acquiring higher-energy collision-induced dissociation (HCD) spectra for a targeted inclusion list of 92 m/z values at a rate of ~6.3 spectra/s. Molecular ions and their corresponding fragments, separated using high-resolution mass analysis, were assigned based on accurate mass measurement. Using this approach, we were able to identify and image both abundant and low-abundance isobaric species within each m/z window. MS/MS analysis enabled efficient separation and identification of isobaric sodium and potassium adducts of phospholipids. Furthermore, we identified several metabolites associated with early pregnancy and obtained the first 2D images of these molecules.

Lanekoff, Ingela T.; Burnum-Johnson, Kristin E.; Thomas, Mathew; Short, Joshua TL; Carson, James P.; Cha, Jeeyeon; Dey, Sudhansu K.; Yang, Pengxiang; Prieto Conaway, Maria C.; Laskin, Julia

2013-10-15T23:59:59.000Z

125

A Mass Spectrometry Study of Isotope Separation in the Laser Plume  

E-Print Network [OSTI]

Gamma Ray Spectrometry . . . . . . . . . . . . . . . . . . .29, 30] Gamma Ray Spectrometry Gamma ray spectrometry willare measured by gamma spectrometry and compared to model

Suen, Timothy Wu

2012-01-01T23:59:59.000Z

126

Metabolic Profiling Directly from the Petri Dish Using Nanospray Desorption Electrospray Ionization Imaging Mass Spectrometry  

SciTech Connect (OSTI)

Understanding molecular interaction pathways in complex biological systems constitutes a treasure trove of knowledge that might facilitate the specific, chemical manipulation of the countless microbiological systems that occur throughout our world. However, there is a lack of methodologies that allow the direct investigation of chemical gradients and interactions in living biological systems, in real time. Here, we report the use of nanospray desorption electrospray ionization (nanoDESI) imaging mass spectrometry for in vivo metabolic profiling of living bacterial colonies directly from the Petri dish with absolutely no sample preparation needed. Using this technique, we investigated single colonies of Shewanella oneidensis MR-1, Bacillus subtilis 3610, and Streptomyces coelicolor A3(2) as well as a mixed biofilm of S. oneidensis MR-1 and B. subtilis 3610. Data from B. subtilis 3610 and S. coelicolor A3(2) provided a means of validation for the method while data from S. oneidensis MR-1 and the mixed biofilm showed a wide range of compounds that this bacterium uses for the dissimilatory reduction of extracellular metal oxides, including riboflavin, iron-bound heme and heme biosynthetic intermediates, and the siderophore putrebactin.

Watrous, Jeramie D.; Roach, Patrick J.; Heath, Brandi S.; Alexandrov, Theodore; Laskin, Julia; Dorrestein, Pieter C.

2013-11-05T23:59:59.000Z

127

Spatial Querying of Imaging Mass Spectrometry Data for the Biochemical Characterization of Anatomical Regions in Tissue  

E-Print Network [OSTI]

Spatial Querying of Imaging Mass Spectrometry Data for the Biochemical Characterization tissue section. In this paper we develop methods that enable spatial querying of MSI data. The objective that adds spatial information to mass spectral biochemical analysis. It delivers insight into the spatial

128

International Journal of Mass Spectrometry 219 (2002) 7377 Protein charge transport in gas phase  

E-Print Network [OSTI]

temperature limit, the rotational energy can be transferred with very high efficiency and hence one obtainsInternational Journal of Mass Spectrometry 219 (2002) 73­77 Protein charge transport in gas phase high charge transport efficiency. (Int J Mass Spectrom 219 (2002) 73­77) © 2002 Elsevier Science B

Sheu, Sheh-Yi

129

The Effect of Solvent on the Analysis of Secondary Organic Aerosol Using Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Solvent-analyte reactions in organic aerosol (OA) extracts prepared for analysis by electrospray ionization mass spectrometry (ESI-MS) were examined. Secondary organic aerosol (SOA) produced by ozonation of d-limonene as well as several test organic chemicals with functional groups typical for OA constituents were dissolved and stored in methanol, d3-methanol, acetonitrile, and d3-acetonitrile to investigate the extent and relative rates of reactions between analyte and solvent. High resolution ESI-MS showed that reactions of carbonyls with methanol produce significant amounts of hemiacetals and acetals on time scales ranging from several minutes to several days, with the reaction rates increasing in acidified solutions. Carboxylic acid groups were observed to react with methanol resulting in the formation of esters. In contrast, acetonitrile extracts showed no evidence of reactions with analyte molecules, suggesting that acetonitrile is the preferred solvent for SOA extraction. The use of solvent-analyte reactivity as an analytical chemistry tool for the improved characterization of functional groups in complex organic mixtures was also demonstrated. Direct comparison between ESI mass spectra of the same SOA samples extracted in reactive (methanol) versus non-reactive (acetonitrile) solvents was used to estimate the relative fractions of ketones (?38%), aldehydes (?6%), and carboxylic acids (?55%) in d-limonene SOA.

Bateman, Adam P.; Walser, Maggie L.; Dessiaterik, Yury; Laskin, Julia; Laskin, Alexander; Nizkorodov, Serguei

2008-10-01T23:59:59.000Z

130

In situ UPb dating of micro-baddeleyite by secondary ion mass spectrometry Axel K. Schmitt a,  

E-Print Network [OSTI]

In situ U­Pb dating of micro-baddeleyite by secondary ion mass spectrometry Axel K. Schmitt a secondary ion mass spectrometry (SIMS) in situ analysis of ng-mass crystals that cannot be efficiently conventional mineral separation methods are not optimized for recovery of such small grains, techniques

131

B American Society for Mass Spectrometry, 2012 DOI: 10.1007/s13361-012-0404-0  

E-Print Network [OSTI]

pI, mobile phase pH) [12], ion suppression of co-eluting analytes [13], and mobile phase flow rateB American Society for Mass Spectrometry, 2012 DOI: 10.1007/s13361-012-0404-0 J. Am. Soc. Mass Improves Peptide Identification by Tandem Mass Spectrometry Jesse G. Meyer, Elizabeth A. Komives Department

Komives, Elizabeth A.

132

High-Resolution Desorption Electrospray Ionization Mass Spectrometry...  

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

between different mechanisms of chemical aging. Citation: Laskin J, A Laskin, PJ Roach, GW Slysz, GA Anderson, S Nizkorodov, DL Bones, and L Nguyen.2010."High-Resolution...

133

Multivariate analysis of progressive thermal desorption coupled gas chromatography-mass spectrometry.  

SciTech Connect (OSTI)

Thermal decomposition of poly dimethyl siloxane compounds, Sylgard{reg_sign} 184 and 186, were examined using thermal desorption coupled gas chromatography-mass spectrometry (TD/GC-MS) and multivariate analysis. This work describes a method of producing multiway data using a stepped thermal desorption. The technique involves sequentially heating a sample of the material of interest with subsequent analysis in a commercial GC/MS system. The decomposition chromatograms were analyzed using multivariate analysis tools including principal component analysis (PCA), factor rotation employing the varimax criterion, and multivariate curve resolution. The results of the analysis show seven components related to offgassing of various fractions of siloxanes that vary as a function of temperature. Thermal desorption coupled with gas chromatography-mass spectrometry (TD/GC-MS) is a powerful analytical technique for analyzing chemical mixtures. It has great potential in numerous analytic areas including materials analysis, sports medicine, in the detection of designer drugs; and biological research for metabolomics. Data analysis is complicated, far from automated and can result in high false positive or false negative rates. We have demonstrated a step-wise TD/GC-MS technique that removes more volatile compounds from a sample before extracting the less volatile compounds. This creates an additional dimension of separation before the GC column, while simultaneously generating three-way data. Sandia's proven multivariate analysis methods, when applied to these data, have several advantages over current commercial options. It also has demonstrated potential for success in finding and enabling identification of trace compounds. Several challenges remain, however, including understanding the sources of noise in the data, outlier detection, improving the data pretreatment and analysis methods, developing a software tool for ease of use by the chemist, and demonstrating our belief that this multivariate analysis will enable superior differentiation capabilities. In addition, noise and system artifacts challenge the analysis of GC-MS data collected on lower cost equipment, ubiquitous in commercial laboratories. This research has the potential to affect many areas of analytical chemistry including materials analysis, medical testing, and environmental surveillance. It could also provide a method to measure adsorption parameters for chemical interactions on various surfaces by measuring desorption as a function of temperature for mixtures. We have presented results of a novel method for examining offgas products of a common PDMS material. Our method involves utilizing a stepped TD/GC-MS data acquisition scheme that may be almost totally automated, coupled with multivariate analysis schemes. This method of data generation and analysis can be applied to a number of materials aging and thermal degradation studies.

Van Benthem, Mark Hilary; Mowry, Curtis Dale; Kotula, Paul Gabriel; Borek, Theodore Thaddeus, III

2010-09-01T23:59:59.000Z

134

On-line electrochemistry/electrospray mass spectrometry: Studies of oxidation of polycyclic aromatic hydrocarbons (PAHs)  

SciTech Connect (OSTI)

Studies of on-line coupling of electrochemistry with mass spectrometry, i.e., {open_quotes}electrochemical mass spectrometry{close_quotes} (EC/MS) date back to work by Bruckenstein et al. in the 1970`s. In these and other early experiments, porous working electrodes or permeable membranes were usually used as the interface between the cell and the MS ionization source which exclusively employed electron ionization (EI). As a result, only volatile products of electrochemical reactions could be detected by the mass line electrochemistry/mass spectroscopy was the coupling of an mass spectrometer (EC/TS/MS) reported by Hambitzer and g an aqueous ammonium acetate thermospray buffer solution, all detected or ammoniated species in the positive ion mode or as deprotonated or acetate adduct species in the negative ion mode. Radical cations or anions were not detected. Although {open_quotes}electrochemically assisted electrospray mass spectrometry{close_quotes} has been progressing for a few years, chiefly due to the pioneering efforts of Van Berkel and coworkers, on-line coupling electrochemistry with electrospray mass spectrometry (EC/ESMS) is still a developing area because of the experimental difficulties involved, such as high voltage hazard to the electrochemistry hardware (e.g. potentiostat), and MS signal suppression caused by the presence of high concentrations of supporting electrolytes. We report the coupling of an electrochemical device on-line with electrospray mass spectrometry (EC/ESMS) to extend the potential of ESMS to detect non-polar neutral compounds, and to monitor and identify intermediates and products generated by electrochemical reactions.

Xu, Xiaoming; Lu, Wenzhe; Cole, R.B. [Univ. of New Orleans, LA (United States)] [and others

1995-12-31T23:59:59.000Z

135

Apparatus and methods for continuous beam fourier transform mass spectrometry  

DOE Patents [OSTI]

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.

McLuckey, Scott A. (Oak Ridge, TN); Goeringer, Douglas E. (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

136

Picoelectrospray Ionization Mass Spectrometry Using Narrow-bore Chemically  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006Photovoltaic Theory and Modeling LosPhysicsEtched Emitters. |

137

Department of Chemistry Mass Spectrometry Sample Submission Form  

E-Print Network [OSTI]

's ID. · You are responsible to pick up your samples within 7 days after the analysis. · Please call 801: [ ] Standard (LRMS) [ ] Exact Mass (HRMS) Ionization type: [ ] ESI [ ] MALDI [ ] EI (GC/MS only) Scans required

Simons, Jack

138

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

SciTech Connect (OSTI)

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.

Noyes, R.A.

1993-01-01T23:59:59.000Z

139

Examination of the rate of peptide biosynthesis in neuroendocrine cell lines using a stable isotopic label and mass spectrometry  

E-Print Network [OSTI]

isotopic label and mass spectrometry Fa-Yun Che,*,1 Quan Yuan,* ,1 Elena Kalinina* and Lloyd D. Fricker-Leu) and used mass spectrometry to measure the biosynthetic rate of c-lipotropin in the AtT-20 cell lines. Keywords: carboxypeptidase, gamma-lipotropin, insulin, prohormone convertase, proinsulin

Tian, Weidong

140

International Journal of Mass Spectrometry 316318 (2012) 259267 Contents lists available at SciVerse ScienceDirect  

E-Print Network [OSTI]

International Journal of Mass Spectrometry 316­318 (2012) 259­267 Contents lists available at SciVerse ScienceDirect International Journal of Mass Spectrometry journal homepage: www.elsevier.com/locate/ijms Influence of a gamma amino acid on the structures and reactivity of peptide a3 ions Matthew C. Berniera

Wysocki, Vicki H.

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Tandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in  

E-Print Network [OSTI]

. Mucopolysaccharidosis type I (MPS-I)4 is a lysosomal storage disorder caused by the deficiency of -L- iduronidase (Id-Scheie syndromes. IdA is essential for the degradation within lysosomes of the glycosamino- glycans dermatan recognition of MPS-I. Flu- orometric, radiometric, and electrospray ionization­ tandem mass spectrometry (ESI

Gelb, Michael

142

FOCUS: HARSH ENVIRONMENT MASS SPECTROMETRY Field Testing of Lake Water Chemistry with a  

E-Print Network [OSTI]

FOCUS: HARSH ENVIRONMENT MASS SPECTROMETRY Field Testing of Lake Water Chemistry with a Portable waters. KOALA is a backpackable MS operated from above the water surface, in which samples are pumped for temperature control of a membrane inlet when steep thermal gradients are present in a water body, as well

Entekhabi, Dara

143

Two-Step Laser Mass Spectrometry of Asphaltenes Andrew E. Pomerantz,*,  

E-Print Network [OSTI]

that high pulse energy and sample concentration promote aggregation of asphaltenes in the plasma plumeTwo-Step Laser Mass Spectrometry of Asphaltenes Andrew E. Pomerantz,*, Matthew R. Hammond, Amy L- heptane, asphaltenes are a highly aromatic, polydisperse mixture consisting of the heaviest and most polar

Zare, Richard N.

144

Surface Analysis by Highly Charged Ion Based Secondary Ion Mass Spectrometry  

E-Print Network [OSTI]

Surface Analysis by Highly Charged Ion Based Secondary Ion Mass Spectrometry T. Schenkel,1 A high vacuum (10^8 torr). In posi- tive polarity, HCI can be decelerated to an impact energy of $1 ke in the interaction of slow (u highly charged ions (e.g., Au69+ ) with solid surfaces increases secondary

145

ORGANIC MASS SPECTROMETRY, VOL. 21, 193-195 (1986) Energy Deposition in [Fe(CO),] ''Upon  

E-Print Network [OSTI]

ORGANIC MASS SPECTROMETRY, VOL. 21, 193-195 (1986) Energy Deposition in [Fe(CO),] ''Upon Collision distributions associated with gas-phase collisional activation using both low and high ion kinetic energies, and the high internal energies accessible, make the ionlsurface collision process superior to gas

Wysocki, Vicki H.

146

Visual Steering and Verification of Mass Spectrometry Data Factorization in Air Quality Research  

E-Print Network [OSTI]

quality research involves the analysis of high-dimensional single particle mass spectrometry data. We data at significantly increased speed and a higher degree of ease. Index Terms--Dimension reduction of numerical error metrics, multi-dimensional data visualization. 1 INTRODUCTION Atmospheric particles increase

Hamann, Bernd

147

Characterization of Individual Nanoparticles and Applications of Nanoparticles in Mass Spectrometry  

E-Print Network [OSTI]

information from single massive cluster impacts. The clusters used in this secondary ion mass spectrometry (SIMS) technique are Au4004+ and C60+. The ionized ejecta from each impact are recorded individually which allows to identify ions emitted from a surface...

Rajagopal Achary, Sidhartha Raja

2011-08-08T23:59:59.000Z

148

Conformational Analysis of Disordered Proteins Using H/D Exchange Mass Spectrometry  

E-Print Network [OSTI]

. The application of hydrogen/deuterium exchange mass spectrometry (H/D-MS) to study IDPs is presented in this dissertation. Results that demonstrate improvements to the H/D-MS method are also presented. A thermoelectrically cooled refrigeration system was developed...

Keppel, Theodore Robert

2013-05-31T23:59:59.000Z

149

Apparatus for preparing a sample for mass spectrometry  

DOE Patents [OSTI]

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.

Villa-Aleman, E.

1994-05-10T23:59:59.000Z

150

Synchrotron based mass spectrometry to investigate the molecular properties of mineral-organic associations  

SciTech Connect (OSTI)

Soil organic matter (OM) is important because its decay drives life processes in the biosphere. Analysis of organic compounds in geological systems is difficult because of their intimate association with mineral surfaces. To date there is no procedure capable of quantitatively separating organic from mineral phases without creating artifacts or mass loss. Therefore, analytical techniques that can (a) generate information about both organic and mineral phases simultaneously and (b) allow the examination of predetermined high-interest regions of the sample as opposed to conventional bulk analytical techniques are valuable. Laser Desorption Synchrotron Postionization (synchrotron-LDPI) mass spectrometry is introduced as a novel analytical tool to characterize the molecular properties of organic compounds in mineral-organic samples from terrestrial systems, and it is demonstrated that when combined with Secondary Ion Mass Spectrometry (SIMS), can provide complementary information on mineral composition. Mass spectrometry along a decomposition gradient in density fractions, verifies the consistency of our results with bulk analytical techniques. We further demonstrate that by changing laser and photoionization energies, variations in molecular stability of organic compounds associated with mineral surfaces can be determined. The combination of synchrotron-LDPI and SIMS shows that the energetic conditions involved in desorption and ionization of organic matter may be a greater determinant of mass spectral signatures than the inherent molecular structure of the organic compounds investigated. The latter has implications for molecular models of natural organic matter that are based on mass spectrometric information.

Liu, Suet Yi; Kleber, Markus; Takahashi, Lynelle K.; Nico, Peter; Keiluweit, Marco; Ahmed, Musahid

2013-04-01T23:59:59.000Z

151

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

SciTech Connect (OSTI)

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.

McLuckey, S.A.; Goeringer, D.E.; Asano, K.G. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

1996-02-01T23:59:59.000Z

152

Spatially resolved thermal desorption/ionization coupled with mass spectrometry  

DOE Patents [OSTI]

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.

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

2013-02-26T23:59:59.000Z

153

National Centre for Biological Sciences Mass Spectrometry Facility  

E-Print Network [OSTI]

: Sample Information Number of samples: Sample ID: Concentration: Solubility: Expected mass (Da): Molecular: Protein Peptide Lipid Nucleic acid Others (specify) Analysis Requirement ESI MS, low resolution ESI MS, high resolution LC-ESI MS LC-ESI MS/MS Others (specify) Signature of research supervisor: Signature

Bhalla, Upinder S.

154

Evaluation of Hypervelocity Gold Nanoparticles for Nanovolume Surface Mass Spectrometry  

E-Print Network [OSTI]

in Figure VI-1 ................................................................................................ 166 VI-3 SI yields for samples containing various amounts of silver and gold on top of a PMMA film analyzed by massive gold clusters... and Bi+ ........ 169 VI-4 Negative mode mass spectrum from atomic-SIMS analysis of a PMMA surface ........................................................................................... 170 VI-5 Proposed structures for fragment ions...

DeBord, John 1986-

2012-08-16T23:59:59.000Z

155

Explanatory Optimization of Protein Mass Spectrometry via Genetic Search  

E-Print Network [OSTI]

of the mass spectrometer settings that accounts for much of this success. Specifically, the conditions of Wales, Aberystwyth, Ceredigion SY23 3DD, U.K. Optimizing experimental conditions for the effective analy that little or no a priori knowledge of the optimal conditions is available. There is much current interest

Fernandez, Thomas

156

Coulomb crystal mass spectrometry in a digital ion trap  

E-Print Network [OSTI]

We present a mass spectrometric technique for identifying the masses and relative abundances of Coulomb-crystallized ions held in a linear Paul trap. A digital radiofrequency waveform is employed to generate the trapping potential, as this can be cleanly switched off, and static dipolar fields subsequently applied to the trap electrodes for ion ejection. Excellent detection efficiency is demonstrated for Ca+ and CaF+ ions from bi-component Ca+/CaF+ Coulomb crystals prepared by reaction of Ca+ with CH3F. A quantitative linear relationship is observed between ion number and the corresponding integrated TOF peak, independent of the ionic species. The technique is applicable to a diverse range of multi-component Coulomb crystals - demonstrated here for Ca+/NH3+/NH4+ and Ca+/CaOH+/CaOD+ crystals - and will facilitate the measurement of ion-molecule reaction rates and branching ratios in complicated reaction systems.

Deb, Nabanita; Smith, Alexander D; Keller, Matthias; Rennick, Christopher J; Heazlewood, Brianna R; Softley, Timothy P

2015-01-01T23:59:59.000Z

157

Ion source for high-precision mass spectrometry  

DOE Patents [OSTI]

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.

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

1982-04-26T23:59:59.000Z

158

Top-Down Mass Spectrometry Imaging of Intact Proteins by LAESI FT-ICR MS  

E-Print Network [OSTI]

Laser Ablation Electrospray Ionization is a recent development in mass spectrometry imaging. It has been shown that lipids and small metabolites can be imaged in various samples such as plant material, tissue sections or bacterial colonies without anysample pre-treatment. Further, laser ablation electrospray ionization has been shown to produce multiply charged protein ions from liquids or solid surfaces. This presents a means to address one of the biggest challenges in mass spectrometry imaging; the identification of proteins directly from biological tissue surfaces. Such identification is hindered by the lack of multiply charged proteins in common MALDI ion sources and the difficulty of performing tandem MS on such large, singly charged ions. We present here top-down identification of intact proteins from tissue with a LAESI ion source combined with a hybrid ion-trap FT-ICR mass spectrometer. The performance of the system was first tested with a standard protein with ECD and IRMPD fragmentation to prove the...

Kiss, András; Reschke, Brent R; Powell, Matthew J; Heeren, Ron M A

2013-01-01T23:59:59.000Z

159

Plume collimation for laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

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.

Vertes, Akos; Stolee, Jessica A.

2014-09-09T23:59:59.000Z

160

{sup 99}Tc bioassay by inductively coupled plasma mass spectrometry (ICP-MS)  

SciTech Connect (OSTI)

A means of analyzing {sup 99}Tc in urine by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. Historically, {sup 99}Tc analysis was based on the radiometric detection of the 293 keV E{sub Max} beta decay product by liquid scintillation or gas flow proportional counting. In a urine matrix, the analysis of{sup 99}Tc is plagued with many difficulties using conventional radiometric methods. Difficulties originate during chemical separation due to the volatile nature of Tc{sub 2}O{sub 7} or during radiation detection due to color or chemical quenching. A separation scheme for {sup 99}Tc detection by ICP-MS is given and is proven to be a sensitive and robust analytical alternative. A comparison of methods using radiometric and mass quantitation of {sup 99}Tc has been conducted in water, artificial urine, and real urine matrices at activity levels between 700 and 2,200 dpm/L. Liquid scintillation results based on an external standard quench correction and a quench curve correction method are compared to results obtained by ICP-MS. Each method produced accurate results, however the precision of the ICP-MS results is superior to that of liquid scintillation results. Limits of detection (LOD) for ICP-MS and liquid scintillation detection are 14.67 and 203.4 dpm/L, respectively, in a real urine matrix. In order to determine the basis for the increased precision of the ICP-MS results, the detection sensitivity for each method is derived and measured. The detection sensitivity for the {sup 99}Tc isotope by ICP-MS is 2.175 x 10{sup {minus}7} {+-} 8.990 x 10{sup {minus}9} and by liquid scintillation is 7.434 x 10{sup {minus}14} {+-} 7.461 x 10{sup {minus}15}. A difference by seven orders of magnitude between the two detection systems allows ICP-MS samples to be analyzed for a period of 15 s compared to 3,600 s by liquid scintillation counting with a lower LOD.

Lewis, L.A.

1998-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Sampling probe for microarray read out using electrospray mass spectrometry  

DOE Patents [OSTI]

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.

Van Berkel, Gary J.

2004-10-12T23:59:59.000Z

162

B American Society for Mass Spectrometry, 2011 DOI: 10.1007/s13361-011-0115-y  

E-Print Network [OSTI]

@snu.ac.kr #12;ionization, (B) low-energy multiple CA in the plume, and (C) post-source high-energy CAB American Society for Mass Spectrometry, 2011 DOI: 10.1007/s13361-011-0115-y J. Am. Soc. Mass-Recognized in MALDI Mass Spectrometry Yong Jin Bae,1 Jeong Hee Moon,2 Myung Soo Kim1 1 Department of Chemistry, Seoul

Kim, Myung Soo

163

Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry  

SciTech Connect (OSTI)

Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

Owens, J; Hok, S; Alcaraz, A; Koester, C

2008-11-13T23:59:59.000Z

164

Matrix effects in inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.

Chen, Xiaoshan

1995-07-07T23:59:59.000Z

165

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

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

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/

Anderson, Gordon

166

Analysis of a Fossil Bone from the Archaeological Settlement Malu Rosu, Romania by Accelerator Mass Spectrometry  

E-Print Network [OSTI]

A fossil bone from the archaeological site Malu Rosu Giurgiu, in Romania has been analyzed by accelerator mass spectrometry to estimate its age by determining its $^{14}$C content. The radiocarbon age of the bone is in agreement with the date obtained by the method for age determination, based on fluorine content. This is the first radiocarbon dating for the final Neolithic period, for this archaeological settlement in the Romanian region.

Agata Olariu; Ion V. Popescu; Ragnar Hellborg; Kristina Stenström; Mikko Faarinen; Per Persson; Bengt Erlandsson; Göran Skog; Emilian Alexandrescu

2001-03-13T23:59:59.000Z

167

Characterization of surface and layered films with cluster secondary ion mass spectrometry  

E-Print Network [OSTI]

.................................... 84 1 CHAPTER I INTRODUCTION Secondary ion mass spectrometry (SIMS) is well recognized a sensitive surface analysis method [1]. It utilizes energetic charged particles (primary ions) to probe surfaces. Impacts from the high energy, high... surprisingly, the most efficient projectiles for this purpose are those depositing a high density of energy. Desorption with keV and MeV Projectiles SIMS operates in two different modes: dynamic SIMS and static SIMS. The major difference between these modes...

Li, Zhen

2008-10-10T23:59:59.000Z

168

2?52Cf plasma desorption mass spectrometry of metal clusters  

E-Print Network [OSTI]

August 1991 Major Subject: Chemistry s Cf PLASMA DESORPTION MASS SPECTROMETRY OF METAL CLUSTERS A Thesis by JANITA MURIEL HUGHES Approved as to style and content by: R. D. ac ane (Chair of Co 'uee) J. P. Fac er (Member) A. . aray (Member) M... and negative ion spectra. However, close-packed complexes like [Pt (CO), g" form cluster cor- responding to the oligomeric species, [(Pt ), (CO)?], from n=2 to n=20. The latter structure contains 520 platinum atoms with an observed mass in excess of m/z 100...

Hughes, Janita Muriel

1991-01-01T23:59:59.000Z

169

Statistical Methods for the Analysis of Mass Spectrometry-based Proteomics Data  

E-Print Network [OSTI]

. This research is supported by the. This work was sponsored by a subcontract from PNNL and by the NIH R25-CA-90301 training grant at TAMU. Additional support was provided by KAUST-IAMCS Innovation grant, by NIH grant DK070146 and by the National Institute...-MS Liquid chromatographyCMass spectrometry M/Z Mass over charge ratio NET Normalized elution time NMC Number of missed cleavage sites NTE Number of tryptic ends PEP Posterior error probability PM Potential matches PMF Probability mass function PNNL...

Wang, Xuan

2012-07-16T23:59:59.000Z

170

Automatic Gain Control in Mass Spectrometry using a Jet Disrupter Electrode in an Electrodynamic Ion Funnel  

SciTech Connect (OSTI)

We report on the use of a jet disrupter electrode in an electrodynamic ion funnel as an electronic valve to regulate the intensity of the ion beam transmitted through the interface of a mass spectrometer in order to perform automatic gain control (AGC). The ion flux is determined by either directly detecting the ion current on the conductance limiting orifice of the ion funnel or using a short mass spectrometry acquisition. Based upon the ion flux intensity, the voltage of the jet disrupter is adjusted to alter the transmission efficiency of the ion funnel to provide a desired ion population to the mass analyzer. Ion beam regulation by an ion funnel is shown to provide an unbiased control to within a few percent of a targeted ion intensity or abundance. The utility of ion funnel AGC was evaluated using a protein tryptic digest analyzed with liquid chromatography Fourier transform ion cyclotron resonance (LC-FTICR) mass spectrometry. The ion population in the ICR cell was accurately controlled to a variety of different levels, which improved data quality and provided better mass measurement accuracy.

Page, Jason S.; Bogdanov, Bogdan; Vilkov, Andrey N.; Prior, David C.; Buschbach, Michael A.; Tang, Keqi; Smith, Richard D.

2005-02-01T23:59:59.000Z

171

Chemical oxidation of tryptic digests to improve sequence coverage in peptide mass fingerprint protein identification  

E-Print Network [OSTI]

Peptide mass fingerprinting (PMF) of protein digests is a widely-accepted method for protein identification in MS-based proteomic studies. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) is the technique of choice in PMF...

Lucas, Jessica Elaine

2004-09-30T23:59:59.000Z

172

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

SciTech Connect (OSTI)

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.

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

2014-12-01T23:59:59.000Z

173

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

American Society for Testing and Materials. Philadelphia

2004-01-01T23:59:59.000Z

174

Nanoelectrospray ion generation for high-throughput mass spectrometry using a micromachined ultrasonic ejector array  

SciTech Connect (OSTI)

Ultrasonic electrospray ionization (ESI) for high-throughput mass spectrometry is demonstrated using a silicon micromachined microarray. The device uses a micromachined ultrasonic atomizer operating in the 900 kHz-2.5 MHz range for droplet generation and a metal electrode in the fluid cavity for ionization. Since the atomization and ionization processes are separated, the ultrasonic ESI source shows the potential for operation at low voltages with a wide range of solvents in contrast with conventional capillary ESI technology. This is demonstrated using the ultrasonic ESI microarray to obtain the mass spectrum of a 10 {mu}M reserpine sample on a time of flight mass spectrometer with 197:1 signal-to-noise ratio at an ionization potential of 200 V.

Aderogba, S.; Meacham, J.M.; Degertekin, F.L.; Fedorov, A.G.; Fernandez, F.M. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2005-05-16T23:59:59.000Z

175

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

SciTech Connect (OSTI)

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.

Jayasekharan, T.; Sahoo, N. K. [Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2013-02-05T23:59:59.000Z

176

Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

American Society for Testing and Materials. Philadelphia

2006-01-01T23:59:59.000Z

177

Using electrospray ionization FTICR mass spectrometry to study competitive binding of inhibitors to carbonic anhydrase  

SciTech Connect (OSTI)

We report a method based on mass spectrometry for the characterization of noncovalent complexes of proteins with mixtures of ligands; this method is relevant to the study of drug leads and may be useful in screening libraries for tight-binding compounds. This study describes the competitive binding of inhibitors derived from para-substituted benzenesulfonamides to bovine carbonic anhydrase II (BCAII, EC 4.2.1.1) using this technique. Relative binding constants and structural information for a mixture of inhibitors can be obtained in a single experiment using ESI-FTICR-MS. The work demonstrates that ESI-MS has significant potential for measuring relative binding affinities and characterizing the structures of ligands associated noncovalently to proteins. We have detected noncovalent complexes in the gas phase for ligands having values of K{sub b} as low as 1.7 x 10{sup 6} M{sup -1} in solution. The technique also allowed identification of tightbinding ligands from small libraries. The structures of inhibitors having similar masses can be identified by the high-resolution and multistep dissociation mass spectrometry of which FTICR is uniquely capable. This range of capabilities for ESI-FTICR-MS should be widely useful in medicinal chemistry. 22 refs., 2 figs.

Cheng, X.; Chen, R.; Bruce, J.E.; Schwartz, B.L.; Anderson, G.A.; Hofstadler, S.A.; Gale, D.C.; Smith, R.D. [Pacific Northwest Lab., Richland, WA (United States); Gao, J.; Sigal, G.B.; Mammen, M.; Whitesides, G.M. [Harvard Univ., Cambridge, MA (United States)

1995-08-30T23:59:59.000Z

178

Multielement ultratrace analysis of molybdenum with high performance secondary ion mass spectrometry  

SciTech Connect (OSTI)

Electron beam melting has been used to obtain ultrapure refractory metals that are gaining importance in metal oxide semiconductor--very large scale integration (MOS--VLSI) processing technology, fusion reactor technology, or as superconducting materials. Although the technology of electron beam melting is well established in the field of production of very clean refractory metals, little is known about the limitations of the method because the impurity level of the final products is frequently below the detection power of common methods for trace analysis. Characterization of these materials can be accomplished primarily by in situ methods like neutron activation analysis and mass spectrometric methods (glow discharge mass spectrometry (GDMS), secondary ion mass spectrometry (SIMS)). A suitable method for quantitative multielement ultratrace bulk analysis of molybdenum with SIMS has been developed. Detection limits of the analyzed elements from 10/sup -7/ g/g down to 10/sup -12/ g/g have been found. Additional information about the distribution of the trace elements has been accumulated.

Virag, A.; Friedbacher, G.; Grasserbauer, M.; Ortner, H.M.; Wilhartitz, P.

1988-07-01T23:59:59.000Z

179

Distance Restraints from Crosslinking Mass Spectrometry: Mining a Molecular Dynamics Simulation Database to Evaluate Lysine-Lysine Distances  

SciTech Connect (OSTI)

Integrative structural biology models the structures of protein complexes that are intractable by classical structural methods (because of extreme size, dynamics, or heterogeneity) by combining computational structural modeling with data from experimental methods. One such method is chemical cross-linking mass spectrometry (XL-MS), in which cross-linked peptides, derived from a covalently cross-linked protein complex and identified by liquid chromatography-mass spectrometry, pinpoint protein residues close in three-dimensional space. The commonly used lysine-reactive N-hydroxysuccinimide ester reagents disuccinimidylsuberate (DSS) and bis(sulfosuccinimidyl)suberate (BS3) have a linker arm that is 11.4 Ĺ long when fully extended. However, XL-MS studies on proteins of known structure frequently report cross-links that exceed this distance. Typically, a tolerance of ~3 Ĺ is added to the theoretical maximum to account for this observation, with little justification for the value chosen. We used the Dynameomics database, a repository of high-quality molecular dynamics simulations of 807 proteins representative of all protein folds, to investigate the change in lysine-lysine distances resulting from native-state dynamics on the time-scale of tens of nanoseconds. We conclude that observed cross-links are consistent with a protein structure if the distance between cross-linked lysine N? atoms is less than the cross-linker length plus 11.3 Ĺ. For DSS or BS3, this corresponds to a C? to C? distance of 30.4 Ĺ. This analysis provides a theoretical basis for the widespread practice of adding a tolerance to the crosslinker length when comparing XL-MS results to structures, and indicates the appropriate values of an XLMS derived distance constraint to use in structural modeling.

Merkley, Eric D.; Rysavy, Steven; Kahraman, Abdullah; Hafen, Ryan P.; Daggett, Valerie; Adkins, Joshua N.

2014-03-18T23:59:59.000Z

180

Method Development of Characterization of N-linked Glycoproteins in Mass Spectrometry  

E-Print Network [OSTI]

in the instruments used in my research. I would also like to thank Dr. Barton F. Haynes, Dr. Hua-Xin Liao, and Laura L. Sutherland at Duke Human Vaccine Research Institute (Duke University, Durham, NC) for supplying HIV Env proteins for my research. I warmly thank...…………………………………………………………………………...115 V. Determination of disulfide bond arrangement of HIV Env protein CON-S gp140 ?CFI by LC/ESI-FTICR mass spectrometry. 5.1. Introduction…………………………………………………………………………120 5.2. Experimental section……………………………………………………………...124 5.3. Results...

Zhang, Ying

2008-02-25T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

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

DOE Patents [OSTI]

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%.

Frank, Matthias (Berkeley, CA); Mears, Carl A. (Oakland, CA); Labov, Simon E. (Berkeley, CA); Benner, W. Henry (Danville, CA)

1999-01-01T23:59:59.000Z

182

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, VOL. 7, 693-699 (1993) Collisions of C&*and Cii at Fluorinated and  

E-Print Network [OSTI]

energy is relatively high, typically 12-15% for small molecules.' Thus, if the efficiency of energy & Sons, Ltd. (e.g. masses areater than 200u) strike surfaces." The high relative energy transferRAPID COMMUNICATIONS IN MASS SPECTROMETRY, VOL. 7, 693-699 (1993) Collisions of C&*and Cii

Wysocki, Vicki H.

183

A Mass Spectrometry Study of Isotope Separation in the Laser Plume  

E-Print Network [OSTI]

1.4.2 Atomic Absorption5.3.2 Atomic Absorption Spectrometry . . . . . . . . . . .ablation and diode laser-atomic absorption spectrometry”,

Suen, Timothy Wu

2012-01-01T23:59:59.000Z

184

Towards secondary ion mass spectrometry on the helium ion microscope: An experimental and simulation based feasibility study with He{sup +} and Ne{sup +} bombardment  

SciTech Connect (OSTI)

The combination of the high-brightness He{sup +}/Ne{sup +} atomic level ion source with secondary ion mass spectrometry detection capabilities opens up the prospect of obtaining chemical information with high lateral resolution and high sensitivity on the Zeiss ORION helium ion microscope. The analytical performance in terms of sputtering yield, useful yield, and detection limit is studied and subsequently optimized by oxygen and cesium flooding. Detection limits down to 10{sup -6} and 10{sup -5} can be obtained for silicon using Ne{sup +} and He{sup +}, respectively. A simulation based study reveals furthermore that a lateral resolution <10 nm can be obtained.

Wirtz, T.; Vanhove, N.; Pillatsch, L.; Dowsett, D. [Department of Science and Analysis of Materials (SAM), Centre de Recherche Public - Gabriel Lippmann, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Sijbrandij, S.; Notte, J. [Carl Zeiss NTS LLC, One Corporation Way, Peabody, Massachusetts 01960 (United States)

2012-07-23T23:59:59.000Z

185

Analyzing Nuclear Fuel Cycles from Isotopic Ratios of Waste Products Applicable to Measurement by Accelerator Mass Spectrometry  

SciTech Connect (OSTI)

An extensive study was conducted to determine isotopic ratios of nuclides in spent fuel that may be utilized to reveal historical characteristics of a nuclear reactor cycle. This forensic information is important to determine the origin of unknown nuclear waste. The distribution of isotopes in waste products provides information about a nuclear fuel cycle, even when the isotopes of uranium and plutonium are removed through chemical processing. Several different reactor cycles of the PWR, BWR, CANDU, and LMFBR were simulated for this work with the ORIGEN-ARP and ORIGEN 2.2 codes. The spent fuel nuclide concentrations of these reactors were analyzed to find the most informative isotopic ratios indicative of irradiation cycle length and reactor design. Special focus was given to long-lived and stable fission products that would be present many years after their creation. For such nuclides, mass spectrometry analysis methods often have better detection limits than classic gamma-ray spectroscopy. The isotopic ratios {sup 151}Sm/{sup 146}Sm, {sup 149}Sm/{sup 146}Sm, and {sup 244}Cm/{sup 246}Cm were found to be good indicators of fuel cycle length and are well suited for analysis by accelerator mass spectroscopy.

Biegalski, S R; Whitney, S M; Buchholz, B

2005-08-24T23:59:59.000Z

186

On-line microdialysis sample cleanup for electrospray ionization mass spectrometry of nucleic acid samples  

SciTech Connect (OSTI)

A major limitation of electrospray ionization mass spectrometry (ESI-MS) for oligonucleotide analysis arises due to sodium adduction, a problem that increases with molecular weight. Sodium adduction can preclude useful measurements when limited sample sizes prevent off-line cleanup. A novel and generally useful on-line microdialysis technique is described for the rapid (nearly 1-5 min) DNA sample cleanup for ESI-MS. Mass spectra of oligonucleotides of different size and sequence showing no significant sodium adduct peaks were obtained using the on-line microdialysis system with sodium chloride concentrations as high as 250 mM. Signal-to-noise ratios were also greatly enhanced compared to direct infusion of the original samples. By using ammonium acetate as the dialysis buffer, it was also found that the noncovalent association of double-stranded oligonucleotides could be preserved during the microdialysis process, allowing analysis by ESI-MS. 33 refs., 6 figs.

Liu, C.; Wu, Q.; Harms, A.C.; Smith, R.D. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States)

1996-09-15T23:59:59.000Z

187

Biases in Ion Transmission Through an Electrospray Ionization-Mass Spectrometry Capillary Inlet  

SciTech Connect (OSTI)

The standard heated capillary inlet of an electrospray ionization mass spectrometry (ESI-MS) interface was compared with shorter versions of the inlet to determine the effects on transmission and ionization efficiencies for low-flow electrosprays. The primary finding of the study was a large bias towards higher mobility species in the electrospray current losses to the inside walls of the inlet. The transmission efficiency increased with decreasing capillary length due to reduced losses along the capillary. A decrease in transmission efficiency was also confirmed for electrosprays of higher conductivity solvents. A direct correlation between mass spectrometry sensitivity and the transmitted electrospray current was not observed as some analytes showed little to no increase in sensitivity while others showed as high as a 15 – fold increase. The variation was shown to at least be partially dependent on the analytes’ mobilities. Higher mobility analytes demonstrated a larger increase in sensitivity when shorter inlets were used. The results indicate that considerable biases against higher mobility species can be produced by the use of long capillary inlets in the ESI-MS interface and strategies are provided to minimize the bias against higher mobility species for efficient ion transmission through the heated capillary interface.

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

2009-12-01T23:59:59.000Z

188

Optimizing a microwave gas ion source for continuous-flow accelerator mass spectrometry  

SciTech Connect (OSTI)

A 2.45 GHz microwave ion source coupled with a magnesium charge exchange canal (C x C) has been successfully adapted to a large acceptance radiocarbon accelerator mass spectrometry system at the National Ocean Sciences Accelerator Mass Spectrometry (AMS) Facility, Woods Hole Oceanographic Institution. CO{sub 2} samples from various preparation sources are injected into the source through a glass capillary at 370 {mu}l/min. Routine system parameters are about 120-140 {mu}A of negative {sup 12}C current after the C x C, leading to about 400 {sup 14}C counts per second for a modern sample and implying a system efficiency of 0.2%. While these parameters already allow us to perform high-quality AMS analyses on large samples, we are working on ways to improve the output of the ion source regarding emittance and efficiency. Modeling calculations suggest modifications in the extraction triode geometry, shape, and size of the plasma chamber could improve emittance and, hence, ion transport efficiency. Results of experimental tests of these modifications are presented.

Reden, K. F. von; Roberts, M. L.; Burton, J. R.; Beaupre, S. R. [Geology and Geophysics Department, Woods Hole Oceanographic Institution (WHOI), Woods Hole, Massachusetts 02543 (United States)

2012-02-15T23:59:59.000Z

189

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

SciTech Connect (OSTI)

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.

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

2011-03-14T23:59:59.000Z

190

Analysis of MALDI FT-ICR Mass Spectrometry Data: a Time Series Donald A. Barkauskasa, Scott R. Kronewitterb, Carlito B. Lebrillab, and David M. Rockec  

E-Print Network [OSTI]

Analysis of MALDI FT-ICR Mass Spectrometry Data: a Time Series Approach Donald A. Barkauskasa/ionization Fourier transform ion cyclotron resonance mass spectrometry is a technique for high mass gamma distribution with varying scale parameter but constant shape parameter and exponent. This enables

Rocke, David M.

191

Standard test method for isotopic abundance analysis of uranium hexa?uoride and uranyl nitrate solutions by multi-collector, inductively coupled plasma-mass spectrometry  

E-Print Network [OSTI]

Standard test method for isotopic abundance analysis of uranium hexa?uoride and uranyl nitrate solutions by multi-collector, inductively coupled plasma-mass spectrometry

American Society for Testing and Materials. Philadelphia

2008-01-01T23:59:59.000Z

192

Nuclear Materials Identification System (NMIS) with Gamma Spectrometry for Attributes of Pu, HEU, and Detection of HE and Chemical Agents  

SciTech Connect (OSTI)

A combined Nuclear Materials Identification System (NMIS)-gamma ray spectrometry system can be used passively to obtain the following attributes of Pu: presence, fissile mass, 240/239 ratio, and metal vs. oxide. This system can also be used with a small, portable, DT neutron generator to measure the attributes of highly enriched uranium (HEU): presence, fissile mass, enrichment, metal vs. oxide; and detect the presence of high explosives (HE). For the passive system, time-dependent coincidence distributions can be used for the presence, fissile mass, metal vs. oxide for Pu, and gamma-ray spectrometry can be used for 239/240 ratio and presence. So presence can be confirmed by two methods. For the active system with a DT neutron generator, all four attributes for both Pu and HEU can be determined from various features of the time-dependent coincidence distribution measurements for both Pu and HEU. Active gamma ray spectrometry would also give presence and 240/239 ratio for Pu, enrichment for HEU, and metal vs. oxide for both. Active gamma ray spectrometry would determine the presence of HE. The various features of time-dependent coincidence distributions and gamma ray spectrometry that determine these attributes are discussed with some examples from previous determinations.

Mihalczo, J. T.; Mattingly, J. K.; Mullens, J. A.; Neal, J. S.

2002-05-01T23:59:59.000Z

193

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

SciTech Connect (OSTI)

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 a gamma spectrometer in the fission product laboratory of the future Jules Horowitz Material Test Reactor. An intermediate step will consist of testing first equipment on an existing experimental facility in the LECA-STAR Hot Cell Laboratory of the CEA Cadarache. This paper presents the scientific and operational stakes linked to fission gas issues, resumes the current state of art for analyzing them in nuclear facilities, then presents the skills gathered through this collaboration to overcome technological bottlenecks. Finally it describes the implementation strategy in nuclear research facilities of the CEA Cadarache. (authors)

Zerega, Y.; Reynard-Carette, C. [Univ. of Provence, Laboratoire Chimie Provence, UMR 6264, Avenue escadrille Normandie - Niemen, F-13397 Marseille (France); Parrat, D. [CEA, Nuclear Energy Div. DEN, CEA Cadarache, F-13108 Saint-Paul-lez-Durance (France); Carette, M. [Univ. of Provence, Laboratoire Chimie Provence, UMR 6264, Avenue escadrille Normandie - Niemen, F-13397 Marseille (France); Brkic, B. [Univ. of Liverpool, Dept. of Electrical Engineering and Electronics, Liverpool L69 3BX (United Kingdom); Lyoussi, A.; Bignan, G. [CEA, Nuclear Energy Div. DEN, CEA Cadarache, F-13108 Saint-Paul-lez-Durance (France); Janulyte, A.; Andre, J. [Univ. of Provence, Laboratoire Chimie Provence, UMR 6264, Avenue escadrille Normandie - Niemen, F-13397 Marseille (France); Pontillon, Y.; Ducros, G. [CEA, Nuclear Energy Div. DEN, CEA Cadarache, F-13108 Saint-Paul-lez-Durance (France); Taylor, S. [Univ. of Liverpool, Dept. of Electrical Engineering and Electronics, Liverpool L69 3BX (United Kingdom)

2011-07-01T23:59:59.000Z

194

Characterization of the microdialysis junction interface for capillary electrophoresis/microelectrospray ionization mass spectrometry  

SciTech Connect (OSTI)

A capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS) interface, based on an electric circuit across a microdialysis membrane surrounding a short capillary segment closely connected to the separation capillary terminus, is demonstrated to be sensitive, efficient, and rugged. A microspray type ionization emitter produces a stable electrospray at the low flow rates provided by CE and thus avoids both the need for a makeup liquid flow provided by liquid junction or sheath flow interfaces and the subsequent dilution and reduction in sensitivity. Reproducibility studies and comparisons with CE/UV and the CE/sheath flow interface with ESI-MS are presented. Additionally, postrun acidification via the microdialysis junction interface is demonstrated and shown to be capable of denaturing the holomyoglobin protein noncovalent complex while maintaining separation efficiency. 21 refs., 7 figs., 1 tab.

Severs, J.C.; Smith, R.D. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States)

1997-06-01T23:59:59.000Z

195

A fast microchannel plate-scintillator detector for velocity map imaging and imaging mass spectrometry  

SciTech Connect (OSTI)

The time resolution achievable using standard position-sensitive ion detectors, consisting of a chevron pair of microchannel plates coupled to a phosphor screen, is primarily limited by the emission lifetime of the phosphor, around 70 ns for the most commonly used P47 phosphor. We demonstrate that poly-para-phenylene laser dyes may be employed extremely effectively as scintillators, exhibiting higher brightness and much shorter decay lifetimes than P47. We provide an extensive characterisation of the properties of such scintillators, with a particular emphasis on applications in velocity-map imaging and microscope-mode imaging mass spectrometry. The most promising of the new scintillators exhibits an electron-to-photon conversion efficiency double that of P47, with an emission lifetime an order of magnitude shorter. The new scintillator screens are vacuum stable and show no signs of signal degradation even over longer periods of operation.

Winter, B.; King, S. J.; Vallance, C., E-mail: claire.vallance@chem.ox.ac.uk [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Rd, Oxford OX1 3TA (United Kingdom); Brouard, M., E-mail: mark.brouard@chem.ox.ac.uk [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Rd, Oxford OX1 3QZ (United Kingdom)

2014-02-15T23:59:59.000Z

196

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

SciTech Connect (OSTI)

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.

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

2014-02-04T23:59:59.000Z

197

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

SciTech Connect (OSTI)

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.

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

2011-06-09T23:59:59.000Z

198

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

SciTech Connect (OSTI)

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.

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.

2014-12-01T23:59:59.000Z

199

Characterization of Coordination Complexes by Desorption Electrospray Mass Spectrometry with a Capillary Target  

SciTech Connect (OSTI)

Metal coordination complexes were formed directly from liquid surfaces using desorption electrospray ionization (DESI) mass spectrometry. The approach is attractive because it separates complexities of ESI spray droplet formation from delivery of the analyte solution, and thereby gets around difficulty resulting from alteration of the spray process by changes in solution chemistry. Cs+, Ba2+, and La3+ coordination complexes were formed using 18-crown-6 (18c6) and triethylphosphate (TEP) as ligands (L), that had the general formula [Mn+(NO3-)n-1(L)m]+. Formation of singly charged cation complexes was preferred, with charge reduction at the metal site accomplished by attachment of nitrate. Using TEP as a model phosphoryl ligand, alkali metals coordinate with up to three ligands, with Cs+ preferring fewer than Na+. Ba2+ and La3+ are formed as ion pair complexes [Ba(NO3)]+ and [La(NO3)2]+, and both will coordinate with up to four TEP ligands. Using 18c6, Cs+ forms a bis-ligand complex. In contrast, [Ba(NO3)]+ prefers a single 18c6 ligand, while La forms mainly [La(NO3)2(18c6)]+, for which DFT calculations suggested a structure in which the nitrate ligands occupy pseudo-axial positions on opposing sides of the crown. Lower abundances of bis-18c6 complexes were also formed together with doubly charged [La(NO3)(18c6)n]2+ complexes (n = 2 – 4). The results suggest an alternative strategy for probing metal speciation in solution that is less perturbed by the droplet formation and ionization mechanisms operating in conventional electrospray ionization mass spectrometry.

Gary S. Groenewold; Anthony D. Appelhans; Michael E. McIlwain; Garold L. Gresham

2011-03-01T23:59:59.000Z

200

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

SciTech Connect (OSTI)

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.

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

2010-08-04T23:59:59.000Z

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201

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

SciTech Connect (OSTI)

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 Thermal Ionization Mass Spectrometer (TIMS) instrument, which applies a similar mass spectrometric technology for resolving high mass isotopes, such as plutonium and uranium. Due to non-compete clauses for DOE, all work has been performed and applied to instruments which are obsolete and are no longer supported by the original vendor.

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

2011-06-06T23:59:59.000Z

202

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

SciTech Connect (OSTI)

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.

Isselhardt, B H

2011-09-06T23:59:59.000Z

203

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

SciTech Connect (OSTI)

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).

Timothy B. Onasch

2011-10-20T23:59:59.000Z

204

OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F  

SciTech Connect (OSTI)

The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates with compounds such as nickel, manganese, sodium, and iron (II), and was dissolved with nitric acid. (3) As much as 30% of the oxalate may have decomposed forming carbon dioxide. The balance does not fully account for all the oxalate added. The offset represents the combined uncertainty in the analyses and sampling.

Poirier, M.; Fink, S.

2011-07-22T23:59:59.000Z

205

Oxalate Mass Balance During Chemical Cleaning in Tank 5F  

SciTech Connect (OSTI)

The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 5F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate.

Poirier, M.; Fink, S.

2011-07-08T23:59:59.000Z

206

Assessment of Non-traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities: Annual Report Year 2  

SciTech Connect (OSTI)

The objective of this work is to identify isotopic ratios suitable for analysis via mass spectrometry that distinguish between commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium, and products from nuclear weapons explosions. Methods will also be determined to distinguish the above from medical and industrial radionuclide sources. Mass spectrometry systems will be identified that are suitable for field measurement of such isotopes in an expedient manner. Significant progress has been made with this project within the past year: (1) Isotope production from commercial nuclear fuel cycles and nuclear weapons fuel cycles have been modeled with the ORIGEN and MCNPX codes. (2) MCNPX has been utilized to calculate isotopic inventories produced in a short burst fast bare sphere reactor (to approximate the signature of a nuclear weapon). (3) Isotopic ratios have been identified that are good for distinguishing between commercial and military fuel cycles as well as between nuclear weapons and commercial nuclear fuel cycles. (4) Mass spectrometry systems have been assessed for analysis of the fission products of interest. (5) A short-list of forensic ratios have been identified that are well suited for use in portable mass spectrometry systems.

Biegalski, S; Buchholz, B

2009-08-26T23:59:59.000Z

207

Combined Atomic Force Microscope-Based Topographical Imaging and Nanometer Scale Resolved Proximal Probe Thermal Desorption/Electrospray Ionization-Mass Spectrometry  

SciTech Connect (OSTI)

Nanometer scale proximal probe thermal desorption/electrospray ionization mass spectrometry (TD/ESI-MS) was demonstrated for molecular surface sampling of caffeine from a thin film using a 30 nm diameter nano-thermal analysis (nano-TA) probe tip in an atomic force microscope (AFM) coupled via a vapor transfer line and ESI interface to a MS detection platform. Using a probe temperature of 350 C and a spot sampling time of 30 s, conical desorption craters 250 nm in diameter and 100 nm deep were created as shown through subsequent topographical imaging of the surface within the same system. Automated sampling of a 5 x 2 array of spots, with 2 m spacing between spots, and real time selective detection of the desorbed caffeine using tandem mass spectrometry was also demonstrated. Estimated from the crater volume (~2x106 nm3), only about 10 amol (2 fg) of caffeine was liberated from each thermal desorption crater in the thin film. These results illustrate a relatively simple experimental setup and means to acquire in automated fashion sub-micrometer scale spatial sampling resolution and mass spectral detection of materials amenable to TD. The ability to achieve MS-based chemical imaging with 250 nm scale spatial resolution with this system is anticipated.

Ovchinnikova, Olga S [ORNL; Nikiforov, Maxim [ORNL; Bradshaw, James A [ORNL; Jesse, Stephen [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

208

Observation of a noncovalent ribonuclease S-protein/S-peptide complex by electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

Electrospray ionization mass spectrometry (ESI-MS) investigations of noncovalently-bound complexes are of great interest because of their relevance to solution biochemistry. ESI-MS is particularly well suited to studies of weak interactions because it is very gentle and it allows studies to be performed under physiological or near-physiological solution conditions. However, it is not yet fully understood which weakly-bound complexes known to exist in solution will be observable by ESI-MS, or what minimum binding strength may be required for ESI-MS observation. Also unclear is whether complexes observed by ESI-MS reflect only species present in the bulk solution, or whether complexes also reflect aggregation in electrospray-generated microdroplets. We address some of these issues by employing ribonuclease S (RNase-S) as a test of the applicability of ESI-MS for analysis of noncovalent complexes. These results show that the ESI mass spectra of R Nase-S can reflect the specificity of binding in solution. 33 refs., 2 figs.

Loo, R.R.O.; Goodlett, D.R.; Smith, R.D.; Loo, J.A. (Pacific Northwest Lab., Richland, WA (United States))

1993-05-19T23:59:59.000Z

209

Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage  

SciTech Connect (OSTI)

Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpine was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.

Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

210

Size Characterization of Colloidal Platinum Nanoparticles by MALDI-TOF Mass Spectrometry  

SciTech Connect (OSTI)

In this work, matrix assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) has been utilized to characterize colloidal platinum nanoparticles synthesized in the 1-4 nm size range. The nanoparticles were prepared via a solution-based method in which the size could be controlled by varying reaction conditions, such as the alcohol used as the reductant. Poly(vinylpyrrolidone), or PVP, (MW = 29,000 g/mol) was employed as a capping agent to stabilize the synthesized nanoparticles in solution. A model for determining the size of the metallic nanoparticle core from MALDI-TOF mass spectra has been developed and verified through correlation with particle sizes from transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements. In this model it was assumed that 1.85 nm nanoparticles are capped by one PVP chain, which was verified through experiments performed with capped and uncapped nanoparticles. Larger nanoparticles are capped by either two (2.60 and 2.94 nm) or three (3.69 nm) PVP chains. These findings clearly indicate the usefulness of MALDI-TOF MS as a technique for fully characterizing nanoscale materials in order to elucidate structure-property relationships.

Navin, Jason K.; Grass, Michael E.; Somorjai, Gabor A.; Marsh, Anderson L.

2009-08-15T23:59:59.000Z

211

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

SciTech Connect (OSTI)

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 phase microextraction (SPME) and identified using gas chromatography - mass spectrometry (GC-MS). Modifications to the sampling apparatus allowed for increased VOC collection efficiency, and reduced the time of sampling and analysis by over 25%. The VOCs are present in breath due to either endogenous production, or exposure to an external source through absorption, inhalation, or ingestion. Detection of these exogenous chemicals can provide information on the prior location and activities of the subject. Breath samples collected before and after exposure in a hardware store and nail salon were analyzed to investigate the prior location of a subject; breath samples collected before and after oral exposure to terpenes and terpenoid compounds, pseudoephedrine, and inhalation exposure to hexamine and other explosive related compounds were analyzed to investigate the prior activity of a subject. The elimination of such compounds from the body was also monitored. In application, this technique may provide an early warning system to identify persons of interest in the prevention and preemption stages of homeland security.

Martin, A N

2009-01-27T23:59:59.000Z

212

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium Sample Handling 8 to 10 Plutonium by Controlled-Potential Coulometry Plutonium by Ceric Sulfate Titration Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 11 to 18 Carbon (Total) by Direct Combustion–Thermal Conductivity 19 to 30 Total Chlorine and Fluorine by Pyrohydrolysis 31 to 38 Sulfur by Distillation Spectrophotometry 39 to 47 Plutonium Isotopic Analysis by Mass Spectrometry Rare Earth Elements by Spectroscopy 48 to 55 Trace Elements by Carrier–Distillation Spectroscopy 56 to 63 Impurities by ICP-AES Impurity Elements by Spark-Source Mass Spectrography 64 to 70 Moisture by the Coulomet...

American Society for Testing and Materials. Philadelphia

2010-01-01T23:59:59.000Z

213

Ionization and transmission efficiency in an electrospray ionization-mass spectrometry interface  

SciTech Connect (OSTI)

The efficiency of sample ionization by electrospray ionization (ESI) and the transmission of the charged droplets and gas-phase ions through an ESI interface were investigated in order to advance the understanding of how these factors affect mass spectrometry (MS) sensitivity. In addition, the effects of the ES emitter distance to the inlet, solution flow rate, and inlet temperature to the ionization and transmission efficiency were characterized. Quantitative measurements of ES current loss throughout the ESI interface were accomplished by electrically isolating the front surface of the interface from the inner wall of the heated inlet capillary, enabling losses on the two surfaces to be distinguished. The ES current lost to the front surface of the ESI interface was also spatially profiled with a linear array of 340-µm-dia. electrodes placed adjacent to the inlet capillary entrance. Current transmitted as gas-phase ions was differentiated from charged droplets and solvent clusters by directly measuring sensitivity with a single quadrupole mass spectrometer. The study has revealed a large sampling efficiency into the inlet capillary (>90% at an emitter distance of 1 mm), a global rather than a local gas dynamic effect on the shape of the ES plume due to the gas flow conductance limit of the inlet capillary, a large (>80%) loss of analyte after transmission through the inlet due to incomplete desolvation at a solution flow rate of 1.0 µL/min, and a decrease in analyte peak intensity at lower temperatures, despite a large increase in ES current transmission efficiency. These studies provide a clearer understanding of the parameters affecting ion transmission into the mass spectrometer, and will serve to guide the design of more efficient instrument interfaces.

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

2007-09-01T23:59:59.000Z

214

Accelerator Mass Spectrometry Measurements of Plutonium in Sediment and Seawater from the Marshall Islands  

SciTech Connect (OSTI)

During the summer 2000, I was given the opportunity to work for about three months as a technical trainee at Lawrence Livermore National Laboratory, or LLNL as I will refer to it hereafter. University of California runs this Department of Energy laboratory, which is located 70 km east of San Francisco, in the small city of Livermore. This master thesis in Radioecology is based on the work I did here. LLNL, as a second U.S.-facility for development of nuclear weapons, was built in Livermore in the beginning of the 1950's (Los Alamos in New Mexico was the other one). It has since then also become a 'science center' for a number of areas like magnetic and laser fusion energy, non-nuclear energy, biomedicine, and environmental science. The Laboratory's mission has changed over the years to meet new national needs. The following two statements were found on the homepage of LLNL (http://www.llnl.gov), at 2001-03-05, where also information about the laboratory and the scientific projects that takes place there, can be found. 'Our primary mission is to ensure that the nation's nuclear weapons remain safe, secure, and reliable and to prevent the spread and use of nuclear weapons worldwide'. 'Our goal is to apply the best science and technology to enhance the security and well-being of the nation and to make the world a safer place.' The Marshall Islands Dose Assessment and Radioecology group at the Health and Ecological Assessments division employed me, and I also worked to some extent with the Centre for Accelerator Mass Spectrometry (CAMS) group. The work I did at LLNL can be divided into two parts. In the first part Plutonium (Pu) measurements in sediments from the Rongelap atoll in Marshall Islands, using Accelerator Mass Spectrometry (AMS) were done. The method for measuring these kinds of samples is well understood at LLNL since soil samples have been measured with AMS for Pu in the past. Therefore it was the results that were of main interest and not the technique. The second part was to take advantage of AMS's very high sensitivity by measure the Pu-concentrations in small volumes (0.04-1 L) of seawater. The technique for using AMS at Pu-measurements in seawater is relatively new and the main task for me was to find out a method that could work in practice. The area where the sediment samples and the water samples were collected are high above background levels for many radionuclides, including Pu, because of the detonation of the nuclear bomb code-named Castle Bravo, in 1954.

Leisvik, M; Hamilton, T

2001-08-01T23:59:59.000Z

215

Facilities: NHMFL 14.5 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Citation: A Pseudoatomic Model of the COPII Cage Obtained from Cryo-Electron Microscopy and Mass Spectrometry,  

E-Print Network [OSTI]

Facilities: NHMFL 14.5 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Citation ultrahigh-resolution 14.5 tesla Fourier transform ion cyclotron resonance mass spectrometry. The Mag

Weston, Ken

216

Chemical tracers of episodic accretion in low-mass protostars  

E-Print Network [OSTI]

Aims: Accretion rates in low-mass protostars can be highly variable in time. Each accretion burst is accompanied by a temporary increase in luminosity, heating up the circumstellar envelope and altering the chemical composition of the gas and dust. This paper aims to study such chemical effects and discusses the feasibility of using molecular spectroscopy as a tracer of episodic accretion rates and timescales. Methods: We simulate a strong accretion burst in a diverse sample of 25 spherical envelope models by increasing the luminosity to 100 times the observed value. Using a comprehensive gas-grain network, we follow the chemical evolution during the burst and for up to 10^5 yr after the system returns to quiescence. The resulting abundance profiles are fed into a line radiative transfer code to simulate rotational spectra of C18O, HCO+, H13CO+, and N2H+ at a series of time steps. We compare these spectra to observations taken from the literature and to previously unpublished data of HCO+ and N2H+ 6-5 from th...

Visser, Ruud; Jorgensen, Jes K

2015-01-01T23:59:59.000Z

217

Observation of the noncovalent quaternary associations of proteins by electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

The noncovalent tetrameric active forms of avidin, concanavalin A (Con A), and adult human hemoglobin (HbA[sub 0]) can be observed intact in the gas phase by electrospray ionization mass spectrometry (ESI-MS). The atmosphere-vacuum ESI interface conditions strongly influence the retention of these weak noncovalent solution associations into the gas phase, as well as the average extent of charging for the subunits upon dissociation. The known solution pH dependence of the dimer-tetramer equilibrium of Con A was observed by ESI-MS, and the intact heterodimeric and -tetrameric active forms of adult human HbA[sub 0], ([alpha][beta]) and ([alpha][beta])[sub 2], with the prosthetic heme groups could also be characterized by ESI-MS. Under harsher interface conditions a species corresponding to a trimer was observed for each of the proteins, a species not known to be formed under physiological conditions. Differences in the relative stabilities of these tetrameric proteins, formed from the known solution structures, are also qualitatively consistent with the gas-phase stability observed with ESI-MS by adjusting the atmosphere-vacuum interface conditions. The hemoglobin tetramer was found to be less stable in the gas phase than either the Con A or avidin tetramer, consistent with solution dissociation constants. 21 refs., 14 figs.

Light-Wahl, K.J.; Schwartz, B.L.; Smith, R.D. (Pacific Northwest Lab., Richland, WA (United States))

1994-06-15T23:59:59.000Z

218

Measurement of Ultra-Low Potassium Contaminations with Accelerator Mass Spectrometry  

E-Print Network [OSTI]

Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Among the radio-isotopes, $\\k40$ is one of the most abundant and yet whose signatures are difficult to reject. Procedures were devised to measure trace potassium concentrations in the inorganic salt CsI as well as in organic liquid scintillator (LS) with Accelerator Mass Spectrometry (AMS), giving, respectively, the $\\k40$-contamination levels of $\\sim 10^{-10}$ and $\\sim 10^{-13}$ g/g. Measurement flexibilities and sensitivities are improved over conventional methods. The projected limiting sensitivities if no excess of potassium signals had been observed over background are $8 \\times 10^{-13}$ g/g and $3 \\times 10^{-17}$ g/g for the CsI and LS, respectively. Studies of the LS samples indicate that the radioactive contaminations come mainly in the dye solutes, while the base solvents are orders of magnitude cleaner. The work demonstrate the possibilities of measuring naturally-occurring isotopes with the AMS techniques.

K. J. Dong

2007-05-01T23:59:59.000Z

219

Measurement of Ultra-Low Potassium Contaminations with Accelerator Mass Spectrometry  

E-Print Network [OSTI]

Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Among the radio-isotopes, $\\k40$ is one of the most abundant and yet whose signatures are difficult to reject. Procedures were devised to measure trace potassium concentrations in the inorganic salt CsI as well as in organic liquid scintillator (LS) with Accelerator Mass Spectrometry (AMS), giving, respectively, the $\\k40$-contamination levels of $\\sim 10^{-10}$ and $\\sim 10^{-13}$ g/g. Measurement flexibilities and sensitivities are improved over conventional methods. The projected limiting sensitivities if no excess of potassium signals had been observed over background are $8 \\times 10^{-13}$ g/g and $3 \\times 10^{-17}$ g/g for the CsI and LS, respectively. Studies of the LS samples indicate that the radioactive contaminations come mainly in the dye solutes, while the base solvents are orders of magnitude cleaner. The work demonstrate the possibilities of measuring naturally-occurring isoto...

Dong, K J

2007-01-01T23:59:59.000Z

220

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

SciTech Connect (OSTI)

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.

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

2013-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
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221

Determination of the stellar (n,gamma) cross section of 40Ca with accelerator mass spectrometry  

E-Print Network [OSTI]

The stellar (n,gamma) cross section of 40Ca at kT=25 keV has been measured with a combination of the activation technique and accelerator mass spectrometry (AMS). This combination is required when direct off-line counting of the produced activity is compromised by the long half-life and/or missing gamma-ray transitions. The neutron activations were performed at the Karlsruhe Van de Graaff accelerator using the quasistellar neutron spectrum of kT=25 keV produced by the 7Li(p,n)7Be reaction. The subsequent AMS measurements were carried out at the Vienna Environmental Research Accelerator (VERA) with a 3 MV tandem accelerator. The doubly magic 40Ca is a bottle-neck isotope in incomplete silicon burning, and its neutron capture cross section determines the amount of leakage, thus impacting on the eventual production of iron group elements. Because of its high abundance, 40Ca can also play a secondary role as "neutron poison" for the s-process. Previous determinations of this value at stellar energies were based o...

Dillmann, I; Heil, M; Käppeler, F; Wallner, A; Forstner, O; Golser, R; Kutschera, W; Priller, A; Steier, P; Mengoni, A; Gallino, R; Paul, M; Vockenhuber, C; 10.1103/PhysRevC.79.065805

2009-01-01T23:59:59.000Z

222

Determination of the stellar (n,gamma) cross section of 40Ca with accelerator mass spectrometry  

E-Print Network [OSTI]

The stellar (n,gamma) cross section of 40Ca at kT=25 keV has been measured with a combination of the activation technique and accelerator mass spectrometry (AMS). This combination is required when direct off-line counting of the produced activity is compromised by the long half-life and/or missing gamma-ray transitions. The neutron activations were performed at the Karlsruhe Van de Graaff accelerator using the quasistellar neutron spectrum of kT=25 keV produced by the 7Li(p,n)7Be reaction. The subsequent AMS measurements were carried out at the Vienna Environmental Research Accelerator (VERA) with a 3 MV tandem accelerator. The doubly magic 40Ca is a bottle-neck isotope in incomplete silicon burning, and its neutron capture cross section determines the amount of leakage, thus impacting on the eventual production of iron group elements. Because of its high abundance, 40Ca can also play a secondary role as "neutron poison" for the s-process. Previous determinations of this value at stellar energies were based on time-of-flight measurements. Our method uses an independent approach, and yields for the Maxwellian-averaged cross section at kT=30 keV a value of 30 keV= 5.73+/-0.34 mb.

I. Dillmann; C. Domingo-Pardo; M. Heil; F. Käppeler; A. Wallner; O. Forstner; R. Golser; W. Kutschera; A. Priller; P. Steier; A. Mengoni; R. Gallino; M. Paul; C. Vockenhuber

2009-07-01T23:59:59.000Z

223

Molecular beam mass spectrometric characterization of biomass pyrolysis products for fuels and chemicals  

SciTech Connect (OSTI)

Converting biomass feedstocks to fuels and chemicals requires rapid characterization of the wide variety of possible feedstocks. The combination of pyrolysis molecular beam mass spectrometry (Py-MBMS) and multivariate statistical analysis offers a unique capability for characterizing these feedstocks. Herbaceous and woody biomass feedstocks that were harvested at different periods were used in this study. The pyrolysis mass spectral data were acquired in real time on the MBMS, and multivariate statistical analysis (factor analysis) was used to analyze and classify Py-MBMS data into compound classes. The effect of harvest times on the thermal conversion of these feedstocks was assessed from these data. Apart from sericea lespedeza, the influence of harvest time on the pyrolysis products of the various feedstocks was insignificant. For sericea lespedeza, samples harvested before plant defoliation were significantly different from those harvested after defoliation. The defoliated plant samples had higher carbohydrate-derived pyrolysis products than the samples obtained from the foliated plant. Additionally, char yields from the defoliated plant samples were lower than those from the foliated plant samples.

Agblevor, F.A.; Davis, M.F.; Evans, R.J. [National Renewal Energy Lab., Golden, CO (United States)

1994-12-31T23:59:59.000Z

224

Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology  

SciTech Connect (OSTI)

This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln{sup 11}]-amyloid {beta}-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will become routine tomorrow.

Nicholas B. Lentz

2007-12-01T23:59:59.000Z

225

High-resolution time-of-flight mass spectrometry fingerprinting of metabolites from cecum and distal colon contents of rats fed resistant starch  

SciTech Connect (OSTI)

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 8-week study, cecal and distal colon content 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.

Anderson, Timothy J. [Ames Laboratory; Jones, Roger W. [Ames Laboratory; Ai, Yongfeng [Iowa State University; Houk, Robert S. [Ames Laboratory; Jane, Jay-lin [Iowa State University; Zhao, Yinsheng [Iowa State University; Birt, Diane F. [Iowa State University; McClelland, John F. [Ames Laboratory

2013-12-04T23:59:59.000Z

226

Very high resolution saturation spectroscopy of lutetium isotopes via c-w single-frequency laser resonance ionization mass spectrometry  

SciTech Connect (OSTI)

In this paper, we discuss the use of Resonance Ionization Mass Spectrometry (RIMS) to perform isotopically selective saturation spectroscopy of lutetium isotopes. Utilizing this technique, it is shown that accurate measurements of the relative frequencies of hyperfine (HF) components for different isotopes easily can be made without the need for an isotopically enriched sample. The precision with which the HF splitting constants can be determined is estimated to be approx.5 times greater than in previous work.

Fearey, B.L.; Parent, D.C.; Keller, R.A.; Miller, C.M.

1987-01-01T23:59:59.000Z

227

A new detector for mass spectrometry: Direct detection of low energy ions using a multi-pixel photon counter  

SciTech Connect (OSTI)

A new type of ion detector for mass spectrometry and general detection of low energy ions is presented. The detector consists of a scintillator optically coupled to a single-photon avalanche photodiode (SPAD) array. A prototype sensor has been constructed from a LYSO (Lu{sub 1.8}Y{sub 0.2}SiO{sub 5}(Ce)) scintillator crystal coupled to a commercial SPAD array detector. As proof of concept, the detector is used to record the time-of-flight mass spectra of butanone and carbon disulphide, and the dependence of detection sensitivity on the ion kinetic energy is characterised.

Wilman, Edward S.; Gardiner, Sara H.; Vallance, Claire [Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Rd, Oxford OX1 3TA (United Kingdom); Nomerotski, Andrei [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Rd, Oxford OX1 3RH (United Kingdom); Turchetta, Renato [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Brouard, Mark [Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Rd, Oxford OX1 3QZ (United Kingdom)

2012-01-15T23:59:59.000Z

228

Measurement of low radioactivity background in a high voltage cable by high resolution inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

The measurement of naturally occurring low level radioactivity background in a high voltage (HV) cable by high resolution inductively coupled plasma mass spectrometry (HR ICP MS) is presented in this work. The measurements were performed at the Chemistry Service of the Gran Sasso National Laboratory. The contributions to the radioactive background coming from the different components of the heterogeneous material were separated. Based on the mass fraction of the cable, the whole contamination was calculated. The HR ICP MS results were cross-checked by gamma ray spectroscopy analysis that was performed at the low background facility STELLA (Sub Terranean Low Level Assay) of the LNGS underground lab using HPGe detectors.

Vacri, M. L. di; Nisi, S.; Balata, M. [Gran Sasso National Laboratory, Chemistry Service, SS 17bis km 18.910, 67100 Assergi (Aq) (Italy)] [Gran Sasso National Laboratory, Chemistry Service, SS 17bis km 18.910, 67100 Assergi (Aq) (Italy)

2013-08-08T23:59:59.000Z

229

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

SciTech Connect (OSTI)

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.

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

2013-10-02T23:59:59.000Z

230

Identification of serum biomarkers for occupational medicamentosa-like dermatitis induced by trichloroethylene using mass spectrometry  

SciTech Connect (OSTI)

Occupational medicamentosa-like dermatitis induced by trichloroethylene (OMLDT) is an autoimmune disease and it has become a serious occupational health hazard. In the present study, we collected fasting blood samples from patients with OMLDT (n = 18) and healthy volunteers (n = 33) to explore serum peptidome patterns. Peptides in sera were purified using weak cation exchange magnetic beads (MB-WCX), and analyzed by matrix-assisted laser desorption ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) and ClinProTools bioinformatics software. The intensities of thirty protein/peptide peaks were significantly different between the healthy control and OMLDT patients. A pattern of three peaks (m/z 2106.3, 2134.5, and 3263.67) was selected for supervised neural network (SNN) model building to separate the OMLDT patients from the healthy controls with a sensitivity of 95.5% and a specificity of 73.8%. Furthermore, two peptide peaks of m/z 4091.61 and 4281.69 were identified as fragments of ATP-binding cassette transporter family A member 12 (ABCA12), and cationic trypsinogen (PRRS1), respectively. Our findings not only show that specific proteomic fingerprints in the sera of OMLDT patients can be served as a differentiated tool of OMLDT patients with high sensitivity and high specificity, but also reveal the novel correlation between OMLDT with ABC transports and PRRS1, which will be of potential value for clinical and mechanistic studies of OMLDT. - Highlights: • Identify 30 differential protein/peptide peaks between OMLDT and healthy control • The test sensitivity and test specificity were 95.5% and 73.8%, respectively. • ABCA12 and PRSS1 were identified as potential biomarkers in OMLDT patients.

Hong, Wen-Xu; Liu, Wei [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Zhang, Yanfang [Shenzhen Prevention and Treatment Center for Occupational Disease, Shenzhen 518001 (China); Huang, Peiwu; Yang, Xifei; Ren, Xiaohu; Ye, Jinbo; Huang, Haiyan [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Tang, Haiyan [Shenzhen Prevention and Treatment Center for Occupational Disease, Shenzhen 518001 (China); Zhou, Guifeng [Medical School of Hunan Normal University, Changsha 410006 (China); Huang, Xinfeng; Zhuang, Zhixiong [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Liu, Jianjun, E-mail: bio-research@hotmail.com [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China)

2013-11-15T23:59:59.000Z

231

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

SciTech Connect (OSTI)

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 materials.

Lorenz, Matthias [ORNL] [ORNL; Ovchinnikova, Olga S [ORNL] [ORNL; Van Berkel, Gary J [ORNL] [ORNL

2014-01-01T23:59:59.000Z

232

Copyright0 1988by San FranciscoPress,Inc., BOX6800, San Franc&o, CA 94101&fM, USA Laser Microprobe Mass Spectrometry  

E-Print Network [OSTI]

Copyright0 1988by San FranciscoPress,Inc., BOX6800, San Franc&o, CA 94101&fM, USA 10 Laser. Bennett, W. Lauwers, A. Vertes, and R. Gijbels Laser microprobe mass spectrometry (LMMS)em- ploys

Vertes, Akos

233

Analysis of liquified coal for nitrogenous bases; separation by high performance liquid chromatography and identification by probe microdistillation/mass spectrometry  

E-Print Network [OSTI]

ANALYSIS OF LIQUIFIED COAL FOR NITROGENOUS BASES; SEPARATION BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY AND IDENTIFICATION BY PROBE MICRODISTILLATION/MASS SPECTROMETRY A Thesis by LEONARD ROYCE SCHRONK Submitted to the Graduate College... AND IDENTIFICATION BY PROBE MICRODISTILLATION/MASS SPECTROMETRY A Thesis by LEONARD ROYCE SCHRONK Approved as to style and content by: Co-Charrman o Commlxtte ) (Co-Chazrman o Committee Me er Hea of Department December 1978 ABSTRACT Analysis of Liquified...

Schronk, Leonard Royce

1978-01-01T23:59:59.000Z

234

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

SciTech Connect (OSTI)

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.

Maxwell, S.

2010-07-26T23:59:59.000Z

235

Transport and mixing of chemical air masses in idealized baroclinic life cycles  

E-Print Network [OSTI]

with stratospheric air is larger for LC2, owing to the presence of the deep cyclonic vortices that entrain and mixTransport and mixing of chemical air masses in idealized baroclinic life cycles L. M. Polvani1 December 2007. [1] The transport, mixing, and three-dimensional evolution of chemically distinct air masses

Esler, Gavin

236

Measurement of Trace I-129 Concentrations in CsI Powder and Organic Liquid Scintillator with Accelerator Mass Spectrometry  

E-Print Network [OSTI]

Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Procedures were devised to measure trace concentrations of I-129 in the inorganic salt CsI as well as in organic liquid scintillator with Accelerator Mass Spectrometry (AMS) which leads to improvement in sensitivities by several orders of magnitude over other methods. No evidence of their existence in these materials were observed. Limits of scintillator, respectively, were derived.These are the first results in a research program whose goals are to develop techniques to measure trace radioactivity in detector materials by AMS.

K. J. Dong

2005-12-01T23:59:59.000Z

237

Measurement of Trace $^{129}I$ Concentrations in CsI Powder and Organic Liquid Scintillator with Accelerator Mass Spectrometry  

E-Print Network [OSTI]

Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Procedures were devised to measure trace concentrations of I-129 in the inorganic salt CsI as well as in organic liquid scintillator with Accelerator Mass Spectrometry (AMS) which leads to improvement in sensitivities by several orders of magnitude over other methods. No evidence of their existence in these materials were observed. Limits of scintillator, respectively, were derived.These are the first results in a research program whose goals are to develop techniques to measure trace radioactivity in detector materials by AMS.

Dong, K J

2007-01-01T23:59:59.000Z

238

affinity-purification mass spectrometry: Topics by E-print Network  

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

give comments on precautions Proposed Structure: Nominal Mass (low res.) Accurate Mass (high res.) Atomic Composition*) MSMS (CID) Resolution Polarity: Positive Negative *) Atomic...

239

International Journal of Mass Spectrometry and Ion Processes, 94 (1989) 63-85 Elsevier Science Publishers B.V., Amsterdam -Printed in The Netherlands  

E-Print Network [OSTI]

in the understanding of the formation of mass spectra, among them the unexpectedly high kinetic energy of the laserInternational Journal of Mass Spectrometry and Ion Processes, 94 (1989) 63-85 Elsevier Science, cloud extensions, ion yields, relative sensitivity factors and ion kinetic energy distributions, i

Vertes, Akos

240

Calculation of Transactinide Homolog Isotope Production Reactions Possible with the Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory  

SciTech Connect (OSTI)

The LLNL heavy element group has been investigating the chemical properties of the heaviest elements over the past several years. The properties of the transactinides (elements with Z > 103) are often unknown due to their low production rates and short half-lives, which require lengthy cyclotron irradiations in order to make enough atoms for statistically significant evaluations of their chemistry. In addition, automated chemical methods are often required to perform consistent and rapid chemical separations on the order of minutes for the duration of the experiment, which can last from weeks to months. Separation methods can include extraction chromatography, liquid-liquid extraction, or gas-phase chromatography. Before a lengthy transactinide experiment can be performed at an accelerator, a large amount of preparatory work must be done both to ensure the successful application of the chosen chemical system to the transactinide chemistry problem being addressed, and to evaluate the behavior of the lighter elemental homologs in the same chemical system. Since transactinide chemistry is literally performed on one single atom, its chemical properties cannot be determined from bulk chemical matrices, but instead must be inferred from the behavior of the lighter elements that occur in its chemical group and in those of its neighboring elements. By first studying the lighter group homologs in a particular chemical system, when the same system is applied to the transactinide element under investigation, its decay properties can be directly compared to those of the homologues, thereby allowing an inference of its own chemistry. The Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory (LLNL) includes a 1 MV Tandem accelerator, capable of accelerating light ions such as protons to energies of roughly 15 MeV. By using the CAMS beamline, tracers of transactinide homolog elements can be produced both for development of chemical systems and for evaluation of homolog chemical properties. CAMS also offers an environment for testing these systems 'online' by incorporating automated chemical systems into the beamline so that tracers can be created, transported, and chemically separated all on the shorter timescales required for transactinide experiments. Even though CAMS is limited in the types and energies of ions they can accelerate, there are still a wide variety of reactions that can be performed there with commercially available target materials. The half-lives of these isotopes vary over a range that could be used for both online chemistry (where shorter half-lives are required) and benchtop tracers studies (where longer lived isotopes are preferred). In this document, they present a summary of tracer production reactions that could be performed at CAMS, specifically for online, automated chemical studies. They are from chemical groups four through seven, 13, and 14, which would be appropriate for studies of elements 104-107, 113, and 114. Reactions were selected that had (a) commercially available target material, (b) half-lives long enough for transport from a target chamber to an automated chemistry system, and (c) cross-sections at CAMS available projectile energies that were large enough to produce enough atoms to result in a statistically relevant signal after losses for transport and chemistry were considered. In addition, the resulting product atoms had to decay with an observable gamma-ray using standard Ge gamma-ray detectors. The table includes calculations performed for both metal targets and their corresponding oxides.

Moody, K J; Shaughnessy, D A; Gostic, J M

2011-11-29T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Time-Resolved Molecular Characterization of Limonene/Ozone Aerosol using High-Resolution Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Molecular composition of limonene/O3 secondary organic aerosol (SOA) was investigated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as a function of reaction time. SOA was generated by ozonation of D-limonene in a reaction chamber and sampled at different time intervals using a cascade impactor. The SOA samples were extracted into acetonitrile and analyzed using a HR-ESI-MS instrument with a resolving power of 100,000 (m/?m). The resulting mass spectra provided detailed information about the extent of oxidation inferred from the O:C ratios, double bond equivalency (DBE) factors, and aromaticity indexes (AI) in hundreds of identified individual SOA species.

Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

2009-09-09T23:59:59.000Z

242

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

SciTech Connect (OSTI)

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.

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

2015-01-01T23:59:59.000Z

243

Poly(3,4-ethylenedioxypyrrole) Modified Emitter Electrode for Substitution of Homogeneous Redox Buffer Agent Hydroquinone in Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

The electrolysis inherent to the operation of the electrospray ionization (ESI) source used with mass spectrometry (MS) is a well-known attendant effect of generating unipolar spray droplets and may affect the analysis of the analyte of interest. Undesirable electrolysis of an analyte may be prevented by limiting the emitter electrode current and/or the mass transport characteristics of the system. However, these ways to avoid analyte electrolysis may not be applcable in all ESI-MS experiments. For example, in the case of specific nanospray systems (e.g. the wire-in-a-capillary bulk-loaded or chip-based tip-loaded nanospray configurations), the solution flow rate is fixed in the 50-500 nL/min range and the electrode surface to volume ratio is large presenting a very effcient analyte to electrode mass transport configuration. In these situations, control over the interfacial potential of the working electrode via homogeneous or traditional heterogeneous (sacrificial metal) redox buffering is a possible way to prevent analyte electrolysis. However, byproducts of these redox buffering approaches can appear in the mass spectra and/or they can chemically alter the analyte. For example, the main reason for using hydroquinone as a homogeneous redox buffer, in addition to its relatively low oxidation potential, is that neither the original compound nor its oxidation product benzoquinone can be detected directly by ESI-MS. However, benzoquinone can alter analytes with thiol functional groups by reacting with those groups via a 1,4-Michael addition.

Peintler-Krivan, Emese [ORNL; Van Berkel, Gary J [ORNL; Kertesz, Vilmos [ORNL

2010-01-01T23:59:59.000Z

244

High Precision Atomic Mass Spectrometry with Applications to Neutrino Physics, Fundamental Constants and Physical Chemistry.  

E-Print Network [OSTI]

?? The Florida State University single-ion cryogenic Penning trap mass spectrometer has been used to precisely measure the masses of the doublets 76Ge/76Se and 74Ge/74Se… (more)

Mount, Brianna Jane

2010-01-01T23:59:59.000Z

245

Molecular characterization of organic aerosol using nanospray desorption/ electrospray ionization mass spectrometry: CalNex 2010 field study  

E-Print Network [OSTI]

Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA c Chemical and Materials Sciences molecular species were detected in the mass range of 50e400 m/z using positive mode ESI of aerosol samples in the 0.18e0.32 mm size range. Our analysis focused on identification of two main groups: compounds

Goldstein, Allen

246

Deconstruction of Activity-Dependent Covalent Modification of Heme in Human Neutrophil Myeloperoxidase by Multistage Mass Spectrometry (MS[superscript 4])  

SciTech Connect (OSTI)

Myeloperoxidase (MPO) is known to be inactivated and covalently modified by treatment with hydrogen peroxide and agents similar to 3-(2-ethoxypropyl)-2-thioxo-2,3-dihydro-1H-purin-6(9H)-one (1), a 254.08 Da derivative of 2-thioxanthine. Peptide mapping by liquid chromatography and mass spectrometry detected modification by 1 in a labile peptide-heme-peptide fragment of the enzyme, accompanied by a mass increase of 252.08 Da. The loss of two hydrogen atoms was consistent with mechanism-based oxidative coupling. Multistage mass spectrometry (MS{sup 4}) of the modified fragment in an ion trap/Orbitrap spectrometer demonstrated that 1 was coupled directly to heme. Use of a 10 amu window delivered the full isotopic envelope of each precursor ion to collision-induced dissociation, preserving definitive isotopic profiles for iron-containing fragments through successive steps of multistage mass spectrometry. Iron isotope signatures and accurate mass measurements supported the structural assignments. Crystallographic analysis confirmed linkage between the methyl substituent of the heme pyrrole D ring and the sulfur atom of 1. The final orientation of 1 perpendicular to the plane of the heme ring suggested a mechanism consisting of two consecutive one-electron oxidations of 1 by MPO. Multistage mass spectrometry using stage-specific collision energies permits stepwise deconstruction of modifications of heme enzymes containing covalent links between the heme group and the polypeptide chain.

Geoghegan, Kieran F.; Varghese, Alison H.; Feng, Xidong; Bessire, Andrew J.; Conboy, James J.; Ruggeri, Roger B.; Ahn, Kay; Spath, Samantha N.; Filippov, Sergey V.; Conrad, Steven J.; Carpino, Philip A.; Guimarăes, Cristiano R.W.; Vajdos, Felix F. (Pfizer)

2013-03-07T23:59:59.000Z

247

Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials  

SciTech Connect (OSTI)

Matrix-assisted laser desorption/ionization(MALDI) mass spectrometry(MS) has been widely used for analysis of biological molecules, especially macromolecules such as proteins. However, MALDI MS has a problem in small molecule (less than 1 kDa) analysis because of the signal saturation by organic matrixes in the low mass region. In imaging MS (IMS), inhomogeneous surface formation due to the co-crystallization process by organic MALDI matrixes limits the spatial resolution of the mass spectral image. Therefore, to make laser desorption/ionization (LDI) MS more suitable for mass spectral profiling and imaging of small molecules directly from raw biological tissues, LDI MS protocols with various alternative assisting materials were developed and applied to many biological systems of interest. Colloidal graphite was used as a matrix for IMS of small molecules for the first time and methodologies for analyses of small metabolites in rat brain tissues, fruits, and plant tissues were developed. With rat brain tissues, the signal enhancement for cerebroside species by colloidal graphite was observed and images of cerebrosides were successfully generated by IMS. In addition, separation of isobaric lipid ions was performed by imaging tandem MS. Directly from Arabidopsis flowers, flavonoids were successfully profiled and heterogeneous distribution of flavonoids in petals was observed for the first time by graphite-assisted LDI(GALDI) IMS.

Cha, Sangwon

2008-05-15T23:59:59.000Z

248

Tile-Based Fisher-Ratio Software for Improved Feature Selection Analysis of Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry Data  

SciTech Connect (OSTI)

Two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC – TOFMS) is a highly capable instrumental platform that produces complex and information-rich multi-dimensional chemical data. The complex data can be overwhelming, especially when many samples (of various sample classes) are analyzed with multiple injections for each sample. Thus, the data must be analyzed in such a way to extract the most meaningful information. The pixel-based and peak table-based algorithmic use of Fisher ratios has been used successfully in the past to reduce the multi-dimensional data down to those chemical compounds that are changing between classes relative to those that are not (i.e., chemical feature selection). We report on the initial development of a computationally fast novel tile-based Fisher-ratio software that addresses challenges due to 2D retention time misalignment without explicitly aligning the data, which is a problem for both pixel-based and peak table- based methods. Concurrently, the tile-based Fisher-ratio software maximizes the sensitivity contrast of true positives against a background of potential false positives and noise. To study this software, eight compounds, plus one internal standard, were spiked into diesel at various concentrations. The tile-based F-ratio software was able to discover all spiked analytes, within the complex diesel sample matrix with thousands of potential false positives, in each possible concentration comparison, even at the lowest absolute spiked analyte concentration ratio of 1.06.

Marney, Luke C.; Siegler, William C.; Parsons, Brendon A.; Hoggard, Jamin C.; Wright, Bob W.; Synovec, Robert E.

2013-10-15T23:59:59.000Z

249

Science of Signatures Workshop on Secondary Ion Mass Spectrometry (SIMS) Applications July 24, 2012  

SciTech Connect (OSTI)

The science of signatures focus areas are: (1) Radiological and Nuclear; (2) Chemical and Materials (including explosives); (3) Biological - Signatures of Disease and Health; (4) Energy; (5) Climate; and (6) Space.

Hickmott, Donald D [Los Alamos National Laboratory; Riciputi, Lee D [Los Alamos National Laboratory

2012-07-23T23:59:59.000Z

250

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)

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.

Wirtz, Tom; Fleming, Yves; Gerard, Mathieu [Department 'Science and Analysis of Materials' (SAM), Centre de Recherche Public, Gabriel Lippmann, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Gysin, Urs; Glatzel, Thilo; Meyer, Ernst [Department of Physics, Universitaet Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Wegmann, Urs [Department of Physics, Universitaet Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Ferrovac GmbH, Thurgauerstr. 72, CH-8050 Zuerich (Switzerland); Maier, Urs [Ferrovac GmbH, Thurgauerstr. 72, CH-8050 Zuerich (Switzerland); Odriozola, Aitziber Herrero; Uehli, Daniel [SPECS Zurich GmbH, Technoparkstr. 1, CH-8005 Zuerich (Switzerland)

2012-06-15T23:59:59.000Z

251

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

SciTech Connect (OSTI)

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.

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

2013-02-01T23:59:59.000Z

252

Principal ComponentAnalysisof Optical EmissionSpectroscopy and MassSpectrometry:Applicationto Reactive Ion Etch  

E-Print Network [OSTI]

of process parameters (i.e., pressure, RF power, and gas mixture) on the optical emission and mass spectra.g., chamber pressure, RF power, and gas flow, while others are internal to the condition of the chamber, e

Shadmehr, Reza

253

Organic aerosol components observed in Northern Hemispheric datasets from Aerosol Mass Spectrometry  

E-Print Network [OSTI]

In this study we compile and present results from the factor analysis of 43 Aerosol Mass Spectrometer (AMS) datasets (27 of the datasets are reanalyzed in this work). The components from all sites, when taken together, ...

Kroll, Jesse

254

Qualitative and quantitative analysis of proteolytically digested glycoproteins by mass spectrometry  

E-Print Network [OSTI]

of glycoproteins, and it is particularly useful in the detection of glycosylation present on proteins. Most glycoproteins are prepared for mass spectrometric analysis by performing a protease digestion, followed by either a separation by HPLC or some other...

Rebecchi, Kathryn

2011-05-31T23:59:59.000Z

255

Determination of particulate lead using aerosol mass spectrometry: MILAGRO/MCMA-2006 observations  

E-Print Network [OSTI]

We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations ...

Salcedo, D.

256

Compositions and chemical bonding in ceramics by quantitative electron energy-loss spectrometry  

SciTech Connect (OSTI)

Quantitative electron energy-loss spectrometry was applied to a range of ceramic materials at a spatial resolution of <5 nm. Analysis of Fe L{sub 23} white lines indicated a low-spin state with a charge transfer of {approximately}1.5 electrons/atom onto the Fe atoms implanted into (amorphized) silicon carbide. Gradients of 2 to 5% in the Co:O stoichiometry were measured across 100-nm-thick Co{sub 3}O{sub 4} layers in an oxidized directionally solidified CoO-ZrO{sub 2} eutectic, with the highest O levels near the ZrO{sub 2}. The energy-loss near-edge structures were dramatically different for the two cobalt oxides; those for CO{sub 3}O{sub 4} have been incorrectly ascribed to CoO in the published literature. Kinetically stabilized solid solubility occurred in an AlN-SiC film grown by low-temperature molecular beam epitaxy (MBE) on {alpha}(6H)-SiC, and no detectable interdiffusion occurred in couples of MBE-grown AlN on SiC following annealing at up to 1750C. In diffusion couples of polycrystalline AlN on SiC, interfacial 8H sialon (aluminum oxy-nitride) and pockets of Si{sub 3}N{sub 4}-rich {beta}{prime} sialon in the SiC were detected.

Bentley, J.; Horton, L.L. [Oak Ridge National Lab., TN (United States); McHargue, C.J. [Tennessee Univ., Knoxville, TN (United States); McKernan, S.; Carter, C.B. [Minnesota Univ., Minneapolis, MN (United States). Dept. of Chemical Engineering; Revcolevschi, A. [Univ. de Paris-Sud, Lab. de Chemie des Solides (France); Tanaka, S.; Davis, R.F. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Materials Science and Engineering

1993-12-31T23:59:59.000Z

257

Chemical Accelerators The phrase "chemical accelerators"  

E-Print Network [OSTI]

bonds, 2 to 10 ev). The methods that have revealed this richness and order of medium- and high-energy, mass spectrometry. While hot-atom studies overcome the energy limitations of thermochemical methods energies of a few electron volts. Most studies of chemical kinetics made by traditional thermochemical

Zare, Richard N.

258

New Mass and Lifetime Measurements of $^{152}$Sm Projectile Fragments with Time-Resolved Schottky Mass Spectrometry  

E-Print Network [OSTI]

The FRS-ESR facilities at GSI provide unique conditions for precision measurements with stored exotic nuclei over a large range in the chart of nuclides. In the present experiment the exotic nuclei were produced via fragmentation of $^{152}$Sm projectiles in a thick beryllium target at 500-600 MeV/u, separated in-flight with the fragment separator FRS, and injected into the storage-cooler ring ESR. Mass and lifetime measurements have been performed with bare and few-electron ions. The experiment and first results will be presented in this contribution.

Yu. A. Litvinov; F. Bosch; H. Geissel; H. Weick; K. Beckert; P. Beller; D. Boutin; C. Brandau; L. Chen; O. Klepper; R. Knöbel; C. Kozhuharov; J. Kurcewicz; S. A. Litvinov; M. Mazzocco; G. Münzenberg; C. Nociforo; F. Nolden; W. Plaß; C. Scheidenberger; M. Steck; B. Sun; M. Winkler

2005-09-15T23:59:59.000Z

259

International Journal of Mass Spectrometry and Zon Processes, 78 (1987) 357-392 Elsevier Science Publishers B.V., Amsterdam -Printed in The Netherlands  

E-Print Network [OSTI]

that significant radial energy transport determines the yields for water ice sputtering at high excitationInternational Journal of Mass Spectrometry and Zon Processes, 78 (1987) 357-392 Elsevier Science, an effective area, and an effective depth, which is determined by the radial dissipation of energy when ions

Johnson, Robert E.

260

International Journal of Mass Spectrometry and Ion Processes, 78 (1987) 237-250 Elsevier Science Publishers B.V., Amsterdam -Printed in The Netherlands  

E-Print Network [OSTI]

of interest with high energy (- 100 MeV) 252Cf fission fragments [l]. This high-energy desorptionInternational Journal of Mass Spectrometry and Ion Processes, 78 (1987) 237-250 Elsevier Science polypeptide. Details of the slow unimolecular decay of high molecular weight multiply protonated polypeptides

Chait, Brian T.

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

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

SciTech Connect (OSTI)

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.

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

2014-12-14T23:59:59.000Z

262

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

DOE Patents [OSTI]

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.

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

2014-02-04T23:59:59.000Z

263

Precise ruthenium fission product isotopic analysis using dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS)  

SciTech Connect (OSTI)

99Tc is a subsurface contaminant of interest at numerous federal, industrial, and international facilities. However, as a mono-isotopic fission product, 99Tc lacks the ability to be used as a signature to differentiate between the different waste disposal pathways that could have contributed to subsurface contamination at these facilities. Ruthenium fission-product isotopes are attractive analogues for the characterization of 99Tc sources because of their direct similarity to technetium with regard to subsurface mobility, and their large fission yields and low natural background concentrations. We developed an inductively coupled plasma mass spectrometry (ICP-MS) method capable of measuring ruthenium isotopes in groundwater samples and extracts of vadose zone sediments. Samples were analyzed directly on a Perkin Elmer ELAN DRC II ICP-MS after a single pass through a 1-ml bed volume of Dowex AG 50W-X8 100-200 mesh cation exchange resin. Precise ruthenium isotopic ratio measurements were achieved using a low-flow Meinhard-type nebulizer and long sample acquisition times (150,000 ms). Relative standard deviations of triplicate replicates were maintained at less than 0.5% when the total ruthenium solution concentration was 0.1 ng/ml or higher. Further work was performed to minimize the impact caused by mass interferences using the dynamic reaction cell (DRC) with O2 as the reaction gas. The aqueous concentrations of 96Mo and 96Zr were reduced by more than 99.7% in the reaction cell prior to injection of the sample into the mass analyzer quadrupole. The DRC was used in combination with stable-mass correction to quantitatively analyze samples containing up to 2-orders of magnitude more zirconium and molybdenum than ruthenium. The analytical approach documented herein provides an efficient and cost-effective way to precisely measure ruthenium isotopes and quantitate total ruthenium (natural vs. fission-product) in aqueous matrixes.

Brown, Christopher F.; Dresel, P. Evan; Geiszler, Keith N.; Farmer, Orville T.

2006-05-09T23:59:59.000Z

264

High-Resolution Electrospray Ionization Mass Spectrometry Analysis of Water- Soluble Organic Aerosols Collected with a Particle into Liquid Sampler  

SciTech Connect (OSTI)

This work demonstrates the utility of a particle-into-liquid sampler (PILS) a technique traditionally used for identification of inorganic ions present in ambient or laboratory aerosols for the analysis of water soluble organic aerosol (OA) using high resolution electrospray ionization mass spectrometry (HR ESI-MS). Secondary organic aerosol (SOA) was produced from 0.5 ppm mixing ratios of limonene and ozone in a 5 m3 Teflon chamber. SOA was collected simultaneously using a traditional filter sampler and a PILS. The filter samples were later extracted with either water or acetonitrile, while the aqueous PILS samples were analyzed directly. In terms of peak intensities, types of detectable compounds, average O:C ratios, and organic mass to organic carbon ratios, the resulting high resolution mass spectra were essentially identical for the PILS and filter based samples. SOA compounds extracted from both filter/acetonitrile extraction and PILS/water extraction accounted for >95% of the total ion current in ESI mass spectra. This similarity was attributed to high solubility of limonene SOA in water. In contrast, significant differences in detected ions and peak abundances were observed for pine needle biomass burning organic aerosol (BBOA) collected with PILS and filter sampling. The water soluble fraction of BBOA is considerably smaller than for SOA, and a number of unique peaks were detectable only by the filter/acetonitrile method. The combination of PILS collection with HR-ESI-MS analysis offers a new approach for molecular analysis of the water-soluble organic fraction in biogenic SOA, aged photochemical smog, and BBOA.

Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

2010-10-01T23:59:59.000Z

265

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

DOE Patents [OSTI]

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.

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

1999-06-29T23:59:59.000Z

266

Combining Laser Ablation/Liquid Phase Collection Surface Sampling and High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid phase sample collection method for surface sampling and ionization with subsequent mass spectral analysis. A commercially available autosampler was adapted to produce a liquid droplet at the end of the syringe injection needle while in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collection was followed by either flow injection or a high performance liquid chromatography (HPLC) separation of the extracted components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the analytical utility of this coupling, thin films of a commercial ink sample containing rhodamine 6G and of mixed isobaric rhodamine B and 6G dyes on glass microscope slides were analyzed. The flow injection and HPLC/ESI-MS analysis revealed successful laser ablation, capture and, with HPLC, the separation of the two compounds. The ablated circular area was about 70 m in diameter for these experiments. The spatial sampling resolution afforded by the laser ablation, as well as the ability to use sample processing methods like HPLC between the sample collection and ionization steps, makes this combined surface sampling/ionization technique a highly versatile analytical tool.

Ovchinnikova, Olga S [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

267

Cadmium binding studies to the earthworm Lumbricus rubellus metallothionein by electrospray mass spectrometry and circular dichroism spectroscopy  

SciTech Connect (OSTI)

The earthworm Lumbricus rubellus has been found to inhabit cadmium-rich soils and accumulate cadmium within its tissues. Two metallothionein (MT) isoforms (1 and 2) have been identified and cloned from L. rubellus. In this study, we address the metalation status, metal coordination, and structure of recombinant MT-2 from L. rubellus using electrospray ionization mass spectrometry (ESI-MS), UV absorption, and circular dichroism (CD) spectroscopy. This is the first study to show the detailed mass and CD spectral properties for the important cadmium-containing earthworm MT. We report that the 20-cysteine L. rubellus MT-2 binds seven Cd{sup 2+} ions. UV absorption and CD spectroscopy and ESI-MS pH titrations show a distinct biphasic demetalation reaction, which we propose results from the presence of two metal-thiolate binding domains. We propose stoichiometries of Cd{sub 3}Cys{sub 9} and Cd{sub 4}Cys{sub 11} based on the presence of 20 cysteines split into two isolated regions of the sequence with 11 cysteines in the N-terminal and 9 cysteines in the C-terminal. The CD spectrum reported is distinctly different from any other metallothionein known suggesting quite different binding site structure for the peptide.

Ngu, Thanh T. [Department of Chemistry, University of Western Ontario, London, Ont., N6A 5B7 (Canada); Sturzenbaum, Stephen R. [School of Biomedical and Health Sciences, King's College, London, SE1 9NH (United Kingdom); Stillman, Martin J. [Department of Chemistry, University of Western Ontario, London, Ont., N6A 5B7 (Canada)]. E-mail: Martin.Stillman@uwo.ca

2006-12-08T23:59:59.000Z

268

Determination of thorium in seawater by neutron activation analysis and mass spectrometry  

SciTech Connect (OSTI)

The recent development of neutron activation analysis and mass spectrometric methods for the determination of /sup 232/Th in seawater has made possible rapid sampling and analysis of this long-lived, non-radiogenic thorium isotope on small-volume samples. The marine geochemical utility of /sup 232/Th, whose concentration in seawater is extremely low, warrants the development of these sensitive techniques. The analytical methods and some results are presented and discussed in this article. 24 refs., 3 figs.

Huh, Chih-An

1987-01-01T23:59:59.000Z

269

Direct Surface Analysis of Time-Resolved Aerosol Impactor Samples with Ultrahigh-Resolution Mass Spectrometry  

E-Print Network [OSTI]

.; Pan, Y.; Mitloehner, F. M. Atmos. Environ. 2012, Submitted. (21) Lundgren, D. A. Journal of the Air Pollution Control Association 1967, 17, 225-9. (22) Schultz, G. A.; Corso, T. N.; Prosser, S. J.; Zhang, S. Anal. Chem. 2000, 72, 4058-4063. 19... in negative health effects caused by air pollution and are linked to increases in respiratory and cardio-vascular diseases2,3. All these particle effects are influenced by the chemical composition of the aerosol particles. A major fraction, often more than 50...

Fuller, Stephen J.; Zhao, Yongjing; Cliff, Steven S.; Wexler, Anthony S.; Kalberer, Markus

2012-10-18T23:59:59.000Z

270

Subscriber access provided by Stanford University Energy & Fuels is published by the American Chemical Society. 1155 Sixteenth  

E-Print Network [OSTI]

Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Article Asphaltene Molecular #12;Asphaltene Molecular-Mass Distribution Determined by Two-Step Laser Mass Spectrometry Andrew E of asphaltenes. Unlike widely used laser desorption/ionization (LDI) mass spectrometry, in which a single laser

Zare, Richard N.

271

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Boron by Titrimetry 7 to 13 Separation of Boron for Mass Spectrometry 14 to 19 Isotopic Composition by Mass Spectrometry 20 to 23 Separation of Halides by Pyrohydrolysis 24 to 27 Fluoride by Ion-Selective Electrode 28 to 30 Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 31 to 33 Trace Elements by Emission Spectroscopy 34 to 46 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (F...

American Society for Testing and Materials. Philadelphia

1994-01-01T23:59:59.000Z

272

Mass Spectrometry Analysis of Proteome-wide Proteolytic Post-translational  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces andMapping the Nanoscale Landscape PrintSurveyMary K.Mass

273

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

SciTech Connect (OSTI)

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

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

2009-09-01T23:59:59.000Z

274

Electrospray mass spectrometry of NeuAc oligomers associated with the C fragment of the tetanus toxin  

SciTech Connect (OSTI)

The Clostridial neurotoxins, botulinum and tetanus, gain entry into neuronal cells by protein recognition involving cell specific binding sites. The sialic or N-acetylneuraminic acid (NeuAc) residues of gangliosides attached to the surface of motor neurons are the suspected recognition and interaction points with Clostridial neurotoxins, although not necessarily the only ones. We have used electrospray ionization mass spectrometry (ESIMS) to examine formation of complexes between the tetanus toxin C fragment, or targeting domain, and carbohydrates containing NeuAc groups to determine how NeuAc residues contribute to ganglioside binding. ESI-MS was used to rapidly and efficiently measure dissociation constants for a number of related NeuAc-containing carbohydrates and NeuAc oligomers, information that has helped identify the structural features of gangliosides that determine their binding to tetanus toxin. The strength of the interactions between the C fragment and (NeuAc){sub n}, are consistent with the topography of the targeting domain of tetanus toxin and the nature of its carbohydrate binding sites. The results suggest that the targeting domain of tetanus toxin contains two binding sites that can accommodate NeuAc (or a dimer). This study also shows that NeuAc must play an important role in ganglioside binding and molecular recognition, a process critical for normal cell function and one frequently exploited by toxins, bacteria and viruses to facilitate their entrance into cells.

Prieto, M C; Whittal, R M; Baldwin, M A; Burlingame, A L; Balhorn, R

2005-04-03T23:59:59.000Z

275

Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry  

E-Print Network [OSTI]

1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

American Society for Testing and Materials. Philadelphia

2010-01-01T23:59:59.000Z

276

The effect of ultrafast laser wavelength on ablation properties and implications on sample introduction in inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

We investigated the role of femtosecond (fs) laser wavelength on laser ablation (LA) and its relation to laser generated aerosol counts and particle distribution, inductively coupled plasma-mass spectrometry (ICP-MS) signal intensity, detection limits, and elemental fractionation. Four different NIST standard reference materials (610, 613, 615, and 616) were ablated using 400 nm and 800 nm fs laser pulses to study the effect of wavelength on laser ablation rate, accuracy, precision, and fractionation. Our results show that the detection limits are lower for 400 nm laser excitation than 800 nm laser excitation at lower laser energies but approximately equal at higher energies. Ablation threshold was also found to be lower for 400 nm than 800 nm laser excitation. Particle size distributions are very similar for 400 nm and 800 nm wavelengths; however, they differ significantly in counts at similar laser fluence levels. This study concludes that 400 nm LA is more beneficial for sample introduction in ICP-MS, particularly when lower laser energies are to be used for ablation.

LaHaye, N. L.; Harilal, S. S.; Diwakar, P. K.; Hassanein, A. [Center for Materials under Extreme Environment, School of Nuclear Engineering Purdue University, West Lafayette, Indiana 47907 (United States); Kulkarni, P. [Centers for Disease Control and Prevention, National Institute of Occupational Safety and Health, Cincinnati, Ohio 45213 (United States)

2013-07-14T23:59:59.000Z

277

Determination of secondary ion mass spectrometry relative sensitivity factors for polar and non-polar ZnO  

SciTech Connect (OSTI)

Zinc oxide (ZnO) is regarded as a promising material for optoelectronic devices, due to its electronic properties. Solely, the difficulty in obtaining p-type ZnO impedes further progress. In this connection, the identification and quantification of impurities is a major demand. For quantitative information using secondary ion mass spectrometry (SIMS), so-called relative sensitivity factors (RSF) are mandatory. Such conversion factors did not yet exist for ZnO. In this work, we present the determined RSF values for ZnO using primary (ion implanted) as well as secondary (bulk doped) standards. These RSFs have been applied to commercially available ZnO substrates of different surface termination (a-plane, Zn-face, and O-face) to quantify the contained impurities. Although these ZnO substrates originate from the same single-crystal, we observe discrepancies in the impurity concentrations. These results cannot be attributed to surface termination dependent RSF values for ZnO.

Laufer, Andreas; Volbers, Niklas; Eisermann, Sebastian; Meyer, Bruno K. [Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany); Potzger, Kay [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany); Geburt, Sebastian; Ronning, Carsten [Institut fuer Festkoerperphysik, Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany)

2011-11-01T23:59:59.000Z

278

Characterization of a Sealed Americium-Beryllium (AmBe) Source by Inductively Coupled Plasma Mass Spectrometry  

SciTech Connect (OSTI)

Two Americium-Beryllium neutron sources were dismantled, sampled (sub-sampled) and analyzed via inductively coupled plasma mass spectrometry (ICP-MS). Characteristics such as “age” since purification, actinide content, trace metal content and inter and intra source composition were determined. The “age” since purification of the two sources was determined to be 25.0 and 25.4 years, respectively. The systematic errors in the “age” determination were ± 4 % 2s. The amount and isotopic composition of U and Pu varied substantially between the sub-samples of Source 2 (n=8). This may be due to the physical means of sub-sampling or the way the source was manufactured. Source 1 was much more consistent in terms of content and isotopic composition (n=3 sub-samples). The Be-Am ratio varied greatly between the two sources. Source 1 had an Am-Be ratio of 6.3 ± 52 % (1s). Source 2 had an Am-Be ratio of 9.81 ± 3.5 % (1s). In addition, the trace element content between the samples varied greatly. Significant differences were determined between Source 1 and 2 for Sc, Sr, Y, Zr, Mo, Ba and W.

James Sommers; Marcos Jimenez; Mary Adamic; Jeffrey Giglio; Kevin Carney

2009-12-01T23:59:59.000Z

279

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

SciTech Connect (OSTI)

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.

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

2011-12-01T23:59:59.000Z

280

Enrichment and Analysis of Nonenzymatically Glycated Peptides: Boronate Affinity Chromatography Coupled with Electron-Transfer Dissociation Mass Spectrometry  

SciTech Connect (OSTI)

Non-enzymatic glycation of peptides and proteins by D-glucose has important implications in the pathogenesis of diabetes mellitus, particularly in the development of diabetic complications. However, no effective high-throughput methods exist for identifying proteins containing this low abundance post-translational modification in bottom-up proteomic studies. In this report, phenylboronate affinity chromatography was used in a two-step enrichment scheme to selectively isolate first glycated proteins and then glycated, tryptic peptides from human serum glycated in vitro. Enriched peptides were subsequently analyzed by alternating electron transfer dissociation (ETD) and collision induced dissociation (CID) tandem mass spectrometry. It was observed that ETD fragmentation mode resulted in a significantly higher number of glycated peptide identifications (87.6% of all identified peptides) versus CID mode (17.0% of all identified peptides), when utilizing dual glycation enrichment on both the protein and peptide level. This study illustrates that phenylboronate affinity chromatography coupled with LC-MS/MS with ETD as the fragmentation mode is an efficient approach for analyses of glycated proteins and can have broad applications in studies of diabetes mellitus.

Zhang, Qibin; Tang, Ning; Brock, Jonathan W.; Mottaz, Heather M.; Ames, Jennifer M.; Baynes, John; Smith, Richard D.; Metz, Thomas O.

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Observation of a small oligonucleotide duplex by electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

Electrospray ionization (ESI) has been demonstrated to be a soft ionization technique, allowing accurate molecular weight determination for biopolymers due to gas-phase multiple charging. Recent results have demonstrated that noncovalent associations can be preserved upon transfer into the gas phase with ESI, providing a new approach to the determination of both structurally-specific and nonspecific noncovalent associations in solution. The mass spectrometric experimental conditions necessary to preserve such noncovalent associations, and the physical constraints upon such, have yet to be elucidated, although it is clear that gentle interface conditions minimizing internal excitation of noncovalent complexes are helpful. Base-paired oligonucleotide hybridization constitutes one of the most important and thoroughly studied noncovalent associations of biopolymers. Initial attempts to observe duplex oligonucleotides resulted in detection of only the monomeric constituents. Since then, the authors have developed interface conditions that are more gentle and yet still provide sufficient molecular ion desolvation to preserve such associations using new instrumentation with a greatly extended m/z range. In this communication, the authors report the successful ionization of duplex oligonucleotides and the conditions necessary for detection by negative ion ESI-MS. 6 refs., 1 fig.

Light-Wahl, K.J.; Springer, D.L.; Winger, B.E.; Edmonds, C.G.; Thrall, B.D.; Smith, R.D. (Pacific Northwest Lab., Richland, WA (United States)); Camp, D.G. II (Eastern Oregon State College, La Grande (United States))

1993-01-27T23:59:59.000Z

282

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

SciTech Connect (OSTI)

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.

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

2009-07-01T23:59:59.000Z

283

Chemical Reaction of Metal-Carbon Binary Cluster Anions by FT-ICR Mass Spectrometer  

E-Print Network [OSTI]

45 48 51 54 57 60 Number of Carbon Atoms Intensity(arbitrary) (a) as injected (b) SWIFTed (c) NO 1sChemical Reaction of Metal-Carbon Binary Cluster Anions by FT-ICR Mass Spectrometer S. Maruyama, M- fullerene and single walled carbon nanotubes are investigated through experimental studies of interaction

Maruyama, Shigeo

284

Fundamental studies of the plasma extraction and ion beam formation processes in inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

The fundamental and practical aspects are described for extracting ions from atmospheric pressure plasma sources into an analytical mass spectrometer. Methodologies and basic concepts of inductively coupled plasma mass spectrometry (ICP-MS) are emphasized in the discussion, including ion source, sampling interface, supersonic expansion, slumming process, ion optics and beam focusing, and vacuum considerations. Some new developments and innovative designs are introduced. The plasma extraction process in ICP-MS was investigated by Langmuir measurements in the region between the skimmer and first ion lens. Electron temperature (T{sub e}) is in the range 2000--11000 K and changes with probe position inside an aerosol gas flow. Electron density (n{sub e}) is in the range 10{sup 8}--10{sup 10} {sup {minus}cm }at the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} near the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} downstream further behind the skimmer. Electron density in the beam leaving the skimmer also depends on water loading and on the presence and mass of matrix elements. Axially resolved distributions of electron number-density and electron temperature were obtained to characterize the ion beam at a variety of plasma operating conditions. The electron density dropped by a factor of 101 along the centerline between the sampler and skimmer cones in the first stage and continued to drop by factors of 10{sup 4}--10{sup 5} downstream of skimmer to the entrance of ion lens. The electron density in the beam expansion behind sampler cone exhibited a 1/z{sup 2} intensity fall-off (z is the axial position). An second beam expansion originated from the skimmer entrance, and the beam flow underwent with another 1/z{sup 2} fall-off behind the skimmer. Skimmer interactions play an important role in plasma extraction in the ICP-MS instrument.

Niu, Hongsen

1995-02-10T23:59:59.000Z

285

Standard test method for isotopic analysis of hydrolyzed uranium hexafluoride and uranyl nitrate solutions by thermal ionization mass spectrometry  

E-Print Network [OSTI]

1.1 This method applies to the determination of isotopic composition in hydrolyzed nuclear grade uranium hexafluoride. It covers isotopic abundance of 235U between 0.1 and 5.0 % mass fraction, abundance of 234U between 0.0055 and 0.05 % mass fraction, and abundance of 236U between 0.0003 and 0.5 % mass fraction. This test method may be applicable to other isotopic abundance providing that corresponding standards are available. 1.2 This test method can apply to uranyl nitrate solutions. This can be achieved either by transforming the uranyl nitrate solution to a uranyl fluoride solution prior to the deposition on the filaments or directly by depositing the uranyl nitrate solution on the filaments. In the latter case, a calibration with uranyl nitrate standards must be performed. 1.3 This test method can also apply to other nuclear grade matrices (for example, uranium oxides) by providing a chemical transformation to uranyl fluoride or uranyl nitrate solution. 1.4 This standard does not purport to address al...

American Society for Testing and Materials. Philadelphia

2005-01-01T23:59:59.000Z

286

Periostin, discovered by nano-flow liquid chromatography and mass spectrometry, is a novel marker of diabetic retinopathy  

SciTech Connect (OSTI)

Research highlights: {yields} In proliferative membrane and epiretinal membrane specimens, the numbers of proteins are 225 and 154, respectively, and 123 proteins are common to both. {yields} Periostin and thrombospondin-1 proteins are unique to the proliferative membrane specimens. {yields} The expression of periostin is significantly up-regulated in proliferative membrane specimens. -- Abstract: Diabetes can lead to serious microvascular complications including proliferative diabetic retinopathy (PDR), the leading cause of blindness in adults. Recent studies using gene array technology have attempted to apply a hypothesis-generating approach to elucidate the pathogenesis of PDR, but these studies rely on mRNA differences, which may or may not be related to significant biological processes. To better understand the basic mechanisms of PDR and to identify potential new biomarkers, we performed shotgun liquid chromatography (LC)/tandem mass spectrometry (MS/MS) analysis on pooled protein extracts from neovascular membranes obtained from PDR specimens and compared the results with those from non-vascular epiretinal membrane (ERM) specimens. We detected 226 distinct proteins in neovascular membranes and 154 in ERM. Among these proteins, 102 were specific to neovascular membranes and 30 were specific to ERM. We identified a candidate marker, periostin, as well as several known PDR markers such as pigment epithelium-derived factor (PEDF). We then performed RT-PCR using these markers. The expression of periostin was significantly up-regulated in proliferative membrane specimens. Periostin induces cell attachment and spreading and plays a role in cell adhesion. Proteomic analysis by LC/MS/MS, which permits accurate quantitative comparison, was useful in identifying new candidates such as periostin potentially involved in the pathogenesis of PDR.

Takada, Michiya [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)] [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan); Ban, Yoshiyuki, E-mail: yshyban@yahoo.co.jp [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)] [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan); Yamamoto, Gou [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan)] [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan); Ueda, Toshihiko; Saito, Yuta; Nishimura, Eiichi; Fujisawa, Kunimi; Koide, Ryohei [Department of Ophthalmology, Showa University School of Medicine, Tokyo (Japan)] [Department of Ophthalmology, Showa University School of Medicine, Tokyo (Japan); Mizutani, Masakazu; Kozawa, Tadahiko; Shiraishi, Yuji [Kozawa Eye Hospital and Diabetes Center, Ibaraki-ken (Japan)] [Kozawa Eye Hospital and Diabetes Center, Ibaraki-ken (Japan); Bando, Yasuhiko [Biosys Technologies, Inc., Meguro, Tokyo (Japan)] [Biosys Technologies, Inc., Meguro, Tokyo (Japan); Tachikawa, Tetsuhiko [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan)] [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan); Hirano, Tsutomu [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)] [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)

2010-08-20T23:59:59.000Z

287

Mass Spectrometry | EMSL  

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

at the cell surface are upregulated within a few hours of purine removal from the media, while other key purine salvage components are upregulated later in the time-course...

288

BIOLOGICAL ANALYSIS Mass Spectrometry  

E-Print Network [OSTI]

Microscope) Analytical Equipment · High Performance Liquid Chromatography · Fast Protein Liquid Chromatography · Gas Chromatography · GC/MS · Elemental Analyser Molecular Biology Equipment · Biorad PCR Machine reactor for scale up studies In-line Particle sizers Rheometers Separation tanks Oscillating column (4m

Greenaway, Alan

289

EMSL - Mass Spectrometry  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct:DirectivesSAND2015-21271 7 6 EIA-176Pageenergy

290

Characterization of human expired breath by solid phase microextraction and analysis using gas chromatography-mass spectrometry and differential mobility spectrometry  

E-Print Network [OSTI]

Breath analysis has potential to become a new medical diagnostic modality. In this thesis, a method for the analysis of human expired breath was developed using gas chromatography-mass spectroscopy. It was subsequently ...

Merrick, William (William F. W.)

2005-01-01T23:59:59.000Z

291

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

SciTech Connect (OSTI)

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.

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

1981-01-01T23:59:59.000Z

292

Real-time monitoring of volatile organic compounds using chemical ionization mass spectroscopy: Final report  

SciTech Connect (OSTI)

Volatile organic compound (VOC) emission to the atmosphere is of great concern to semiconductor manufacturing industries, research laboratories, the public, and regulatory agencies. Some industries are seeking ways to reduce emissions by reducing VOCs at the point of use (or generation). This paper discusses the requirements, design, calibration, and use of a sampling inlet/quadrupole mass spectrometer system for monitoring VOCs in a semiconductor manufacturing production line. The system uses chemical ionization to monitor compounds typically found in the lithography processes used to manufacture semiconductor devices (e.g., acetone, photoresist). The system was designed to be transportable from tool to tool in the production line and to give the operator real-time feedback so the process(es) can be adjusted to minimize VOC emissions. Detection limits ranging from the high ppb range for acetone to the low ppm range fore other lithography chemicals were achieved using chemical ionization mass spectroscopy at a data acquisition rate of approximately 1 mass spectral scan (30 to 200 daltons) per second. A demonstration of exhaust VOC monitoring was performed at a working semiconductor fabrication facility during actual wafer processing.

Thornberg, S.M.; Mowry, C.D.; Keenan, M.R.; Bender, S.F.A. [Sandia National Labs., Albuquerque, NM (United States). Gas Analysis Lab.; Owen, T. [Intel Corp., Rio Rancho, NM (United States)

1997-04-01T23:59:59.000Z

293

Chemical and Physical Characterization of Therapeutic Proteins in Solution and Amorphous Solids  

E-Print Network [OSTI]

The chemical and physical stability of proteins in solution and solids was addressed in this dissertation. Protein-excipient interactions in lyophilized solids were studied by hydrogen/deuterium exchange with mass spectrometry ...

Sinha, Sandipan

2008-06-16T23:59:59.000Z

294

E-Print Network 3.0 - absorption spectrometry etaas Sample Search...  

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

With Confirmation of Accuracy by Inductively Coupled Plasma Mass Spectrometry and Atomic Absorption Spectrometry... -LEAFS uses absorption; graphite furnace; inductively...

295

A Perspective on the Maillard Reaction and the Analysis of Protein Glycation by Mass Spectrometry: Probing the Pathogenesis of Chronic Disease  

SciTech Connect (OSTI)

The Maillard reaction, starting from the glycation of protein and progressing to the formation of advanced glycation end-products (AGEs), is implicated in the development of complications of diabetes mellitus, as well as in the pathogenesis of cardiovascular, renal, and neurodegenerative diseases. In this perspective review, we provide on overview on the relevance of the Maillard reaction in the pathogenesis of chronic disease and discuss traditional approaches and recent developments in the analysis of glycated proteins by mass spectrometry. We propose that proteomics approaches, particularly bottom-up proteomics, will play a significant role in analyses of clinical samples leading to the identification of new markers of disease development and progression.

Zhang, Qibin; Ames, Jennifer M.; Smith, Richard D.; Baynes, John; Metz, Thomas O.

2008-12-18T23:59:59.000Z

296

Depth distribution of lithium in oxidized binary Al-Li alloys determined by secondary ion mass spectrometry and neutron depth profiling  

SciTech Connect (OSTI)

Oxidation of binary Al-Li alloys during short exposures at 530 C and long exposures at 200 C was studied with regard to the Li distribution. Secondary ion mass spectrometry (SIMS) and neutron depth profiling (NDP) were used to obtain quantitative Li depth profiles across the surface oxide layer and the underlying alloy. The underlying alloy was depleted in Li as a result of oxidation at 530 and 200 C. The SIMS and NDP results showed good mutual agreement and were used to evaluate the oxide thickness, the Li concentration at the oxide-ally interface, and the mass balance between oxide and alloy. The Li depletion profiles in the alloy were also calculated using the interdiffusion coefficients reported in the literature and compared with the measured profiles; the two profiles differed at 530 C but showed good agreement at 200 C.

Soni, K.K. (Univ. of Chicago, IL (United States)); Williams, D.B. (Lehigh Univ., Bethlehem, PA (United States)); Newbury, D.E.; Chi, P.; Downing, R.G.; Lamaza, G. (National Inst. of Standards and Technology, Gaithersburg, MD (United States))

1993-01-01T23:59:59.000Z

297

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry of coal liquids produced during a coal liquefaction process  

SciTech Connect (OSTI)

Comprehensive two-dimensional gas chromatography (GC) coupled to time-of-flight mass spectrometry (MS) has been applied to the analysis of coal-derived liquids from the former British Coal Point-of-Ayr coal liquefaction plant. The feed to the hydrocracker and the resulting product were analyzed. The results refer almost exclusively to the plant-derived recycle solvent, known as the liquefaction solvent; the molecular mass range of the GC does not exceed that of the solvent. The method allows for the resolution of the numerous structural isomers of tetralin and methyl indan, one pair of hydrogen-donor (necessary for the dissolution of coal) and isomeric nondonor (that reduce the hydrogen donors) components of the recycle solvent. In addition, the n-alkanes that concentrate in the recycle solvent are easily observed in comparison with the results from one-dimensional GC-MS. 24 refs., 6 figs., 1 tab.

Jacqui F. Hamilton; Alistair. C. Lewis; Marcos Millan; Keith D. Bartle; Alan A. Herod; Rafael Kandiyoti [University of York, York (United Kingdom). Department of Chemistry

2007-01-15T23:59:59.000Z

298

Airfoil sampling of a pulsed Laval beam with tunable vacuum ultraviolet (VUV) synchrotron ionization quadrupole mass spectrometry: Application to low--temperature kinetics and product detection  

SciTech Connect (OSTI)

A new pulsed Laval nozzle apparatus with vacuum ultraviolet (VUV) synchrotron photoionization quadrupole mass spectrometry is constructed to study low-temperature radicalneutralchemical reactions of importance for modeling the atmosphere of Titan and the outer planets. A design for the sampling geometry of a pulsed Laval nozzle expansion has beendeveloped that operates successfully for the determination of rate coefficients by time-resolved mass spectrometry. The new concept employs airfoil sampling of the collimated expansion withexcellent sampling throughput. Time-resolved profiles of the high Mach number gas flow obtained by photoionization signals show that perturbation of the collimated expansion by theairfoil is negligible. The reaction of C2H with C2H2 is studied at 70 K as a proof-of-principle result for both low-temperature rate coefficient measurements and product identification basedon the photoionization spectrum of the reaction product versus VUV photon energy. This approach can be used to provide new insights into reaction mechanisms occurring at kinetic ratesclose to the collision-determined limit.

Soorkia, Satchin; Liu, Chen-Lin; Savee, John D.; Ferrell, Sarah J.; Leone, Stephen R.; Wilson, Kevin R.

2011-10-12T23:59:59.000Z

299

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride  

E-Print Network [OSTI]

1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

American Society for Testing and Materials. Philadelphia

2011-01-01T23:59:59.000Z

300

Intracellular Water Exchange for Measuring the Dry Mass, Water Mass and Changes in Chemical Composition of Living Cells  

E-Print Network [OSTI]

We present a method for direct non-optical quantification of dry mass, dry density and water mass of single living cells in suspension. Dry mass and dry density are obtained simultaneously by measuring a cell’s buoyant ...

Cermak, Nathan

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301

Synchrotron Vacuum-Ultraviolet Postionization Mass Spectrometry with Laser and Ion Probes for Intact Molecular Spatial Mapping of Lignin  

E-Print Network [OSTI]

and Biosynthesis of Lignin; Springer-Verlag: Berlin, 1968. (chemical imaging studies of lignin and related compounds.and Alkali and Organosolv Lignins with Synchrotron Vacuum-UV

Takahashi, Lynelle Kazue

2011-01-01T23:59:59.000Z

302

Molecular Inventories and Chemical Evolution of Low-mass Protostellar Envelopes  

E-Print Network [OSTI]

This paper presents the first substantial study of the chemistry of the envelopes around a sample of 18 low-mass pre- and protostellar objects for which physical properties have previously been derived from radiative transfer modeling of their dust continuum emission. Single-dish line observations of 24 transitions of 9 molecular species (not counting isotopes) including HCO+, N2H+, CS, SO, SO2, HCN, HNC, HC3N and CN are reported. The line intensities are used to constrain the molecular abundances by comparison to Monte Carlo radiative transfer modeling of the line strengths. An empirical chemical network is constructed on the basis of correlations between the abundances of various species. For example, it is seen that the HCO+ and CO abundances are linearly correlated, both increasing with decreasing envelope mass. Species such as CS, SO and HCN show no trend with envelope mass. In particular no trend is seen between ``evolutionary stage'' of the objects and the abundances of the main sulfur- or nitrogen-containing species. Among the nitrogen-bearing species abundances of CN, HNC and HC3N are found to be closely correlated, which can be understood from considerations of the chemical network. The CS/SO abundance ratio is found to correlate with the abundances of CN and HC3N, which may reflect a dependence on the atomic carbon abundance. An anti-correlation is found between the deuteration of HCO+ and HCN, reflecting different temperature dependences for gas-phase deuteration mechanisms. The abundances are compared to other protostellar environments. In particular it is found that the abundances in the cold outer envelope of the previously studied class 0 protostar IRAS16293-2422 are in good agreement with the average abundances for the presented sample of class 0 objects.

J. K. Jorgensen; F. L. Schoeier; E. F. van Dishoeck

2003-12-09T23:59:59.000Z

303

Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source for Elemental Mass Spectrometry: Preliminary Parametric Evaluation and Figures of Merit  

SciTech Connect (OSTI)

A new, low power ionization source for the elemental analysis of aqueous solutions has recently been described. The liquid sampling-atmospheric pressure glow discharge (LS-APGD) source operates at relatively low currents (<20 mA) and solution flow rates (<50 ?L min-1), yielding a relatively simple alternative for atomic mass spectrometry applications. The LS-APGD has been interfaced to what is otherwise an organic, LC-MS mass analyzer, the Thermo Scientific Exactive Orbitrap without any modifications; other than removing the electrospray ionization (ESI) source supplied with that instrument. A glow discharge is initiated between the surface of the test solution exiting a glass capillary and a metallic counter electrode mounted at a 90° angle and separated by a distance of ~5 mm. As with any plasma-based ionization source, there are key discharge operation and ion sampling parameters that affect the intensity and composition of the derived mass spectra; including signal-to-background ratios. We describe here a preliminary parametric evaluation of the roles of discharge current, solution flow rate, argon sheath gas flow rate, and ion sampling distance as they apply on this mass analyzer system. A cursive evaluation of potential matrix effects due to the presence of easily ionized elements (EIEs) indicate that sodium concentrations of up to 500 ?g mL-1 generally cause suppressions of less than 50%, dependant upon the analyte species. Based on the results of this series of studies, preliminary limits of detection (LOD) have been established through the generation of calibration functions. Whilst solution-based concentrations LOD levels of 0.02 – 2 ?g mL-1 3 are not impressive on the surface, the fact that they are determined via discrete 5 ?L injections leads to mass-based detection limits at picogram to singlenanogram levels. The overhead costs associated with source operation (10 W d.c. power, solution flow rates of <50 ?L min-1, and gas flow rates <10 mL min-1) are very attractive. While further optimization in the source design is suggested here, it is believed that the LS-APGD ion source may present a practical alternative to inductively-coupled plasma (ICP) sources typically employed in elemental mass spectrometry.

Quarles, C. Derrick; Carado, Anthony J.; Barinaga, Charles J.; Koppenaal, David W.; Marcus, R. Kenneth

2012-01-01T23:59:59.000Z

304

An On-Target Performic Acid Oxidation Method Suitable for Disulfide Bond Elucidation Using Capillary Electrophoresis - Mass Spectrometry  

E-Print Network [OSTI]

methods before or after MS detection have been developed to aid in disulfide bond assignment, such as tandem MS followed by database searching or modification of the disulfide bond via chemical reduction or oxidation. Despite these technological...

Williams, Brad J.

2011-08-08T23:59:59.000Z

305

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

SciTech Connect (OSTI)

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.

Witte, Travis

2011-11-30T23:59:59.000Z

306

Detection and quantitation of benzo(a)pyrene-derived DNA adducts in mouse liver by liquid chromatography - tandem mass spectrometry: comparison with P-32-postlabeling  

SciTech Connect (OSTI)

The polycyclic aromatic hydrocarbon, benzo(a)pyrene (B(a)P) is a proven animal carcinogen that is potentially carcinogenic to humans. B( a)P is an ubiquitous environmental pollutant and is also present in tobacco smoke, coal tar, automobile exhaust emissions, and charred food. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using electrospray ionization and selected reaction monitoring (SRM) has been developed for the detection of 10-(deoxyguanosin-N{sub 2}-yl)-7,8,9-trihydroxy-7,8,9,10- tetrahydrobenzo(a)pyrene (B(a)PDE-N{sub 2}dG) adducts formed in DNA following the metabolic activation of B(a)P to benzo(a) pyrene-7,8-dihydrodiol-9,10-epoxide (B(a)PDE).

Singh, R.; Gaskell, M.; Le Pla, R.C.; Kaur, B.; Azim-Araghi, A.; Roach, J.; Koukouves, G.; Souliotis, V.L.; Kyrtopoulos, S.A.; Farmer, P.B. [University of Leicester, Leicester (United Kingdom)

2006-06-19T23:59:59.000Z

307

MANTRA: An Integral Reactor Physics Experiment to Infer Actinide Capture Cross-sections from Thorium to Californium with Accelerator Mass Spectrometry  

SciTech Connect (OSTI)

The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor 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 Spectrometry 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, 244Cm and 248Cm.

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

2011-08-01T23:59:59.000Z

308

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)

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.

Schmidt, S.; Greczynski, G.; Jensen, J.; Hultman, L. [Thin Film Physics Div., Department of Physics (IFM), Linkoeping University, SE-581 83 (Sweden); Czigany, Zs. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklos ut 29-33. H-1121 Budapest (Hungary)

2012-07-01T23:59:59.000Z

309

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

SciTech Connect (OSTI)

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.

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.

2011-09-13T23:59:59.000Z

310

C-O-H ratios of silicate melt inclusions in basalts from the Galapagos spreading center near 95 degree W: A leaser decrepitation mass spectrometry study  

SciTech Connect (OSTI)

Volatile ratios (primarily of H{sub 2}O and CO{sub 2}) in individual silicate melt (glass) inclusions in minerals have been analyzed using laser volatilization and mass spectrometry. A Nd-glass laser was used to produce 50-micrometer diameter pits in silicate melt inclusions. Released volatiles were analyzed directly with a computer-controlled quadrupole mass spectrometer. The mean CO{sub 2}/H{sub 2}O from the propagating rift (0.245 {plus minus} 0.068) silicate glass inclusions is significantly lower than that of the actively failing rift (0.641 {plus minus} 0.241); this difference probably reflects different degrees of degassing during contrasting magmatic histories for the two regions. Relatively undifferentiated failing rift magmas must have relatively short crustal residence time prior to eruption and, therefore, have not undergone significant degassing of CO{sub 2}, as would appear to be the case for the more highly fractionated propagating rift magmas. The laser-mass spectrometric system described herein has the ability to act as a point-source probing device that can differentiate between the various volatile sites in minerals and rocks (as well as synthetic materials) on a micrometer scale.

Yonover, R.N.; Sinton, J.M. (Univ. of Hawaii, Honolulu (USA)); Gibson, E.K. (NASA/Johnson Space Center, Houston, TX (USA)); Sommer, M.A.

1989-12-01T23:59:59.000Z

311

Devices for collecting chemical compounds  

DOE Patents [OSTI]

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Scott, Jill R; Groenewold, Gary S

2013-12-24T23:59:59.000Z

312

Advances in X-Ray Chemical Analysis, Japan, 45 (2014) ISSN 0911-7806 Report on 10th Chinese X-Ray Spectrometry Conference (CXRSC)  

E-Print Network [OSTI]

and Information Technology), Dr. Yidong Zhao (Institute of High Energy Physics of Chinese Academy of Sciences-Ray Spectrometry Conference (CXRSC) Ying LIU #12;#12;45 345 Report on 10th Chinese X-Ray Spectrometry Conference (CXRSC) Adv. X-Ray. Chem. Anal., Japan 45, pp.345-348 (2014) Report on 10th Chinese X-Ray Spectrometry

Jun, Kawai

313

Advanced Mass Calibration and Visualization for FT-ICR Mass Spectromet...  

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

for FT-ICR Mass Spectrometry Imaging. Abstract: Mass spectrometry imaging by Fourier transform ion cyclotron resonance (FT-ICR) yields hundreds of unique peaks, many of which...

314

Applications of High-Resolution Electrospray Ionization Mass Spectrometry to Measurements of Average Oxygen to Carbon Ratios  

E-Print Network [OSTI]

, California 92617, United States Chemical and Materials Sciences Division and § Environmental Molecular. A correlation was found between the ratio of the ionization efficiencies in the positive (+) and negative identification of the aerosol constituents. INTRODUCTION Due to the molecular complexity inherent to secondary

Nizkorodov, Sergey

315

Characterization of Diesel Fuel by Chemical Separation Combined with Capillary Gas Chromatography (GC) Isotope Ratio Mass Spectrometry (IRMS)  

SciTech Connect (OSTI)

The purpose of this study was to perform a preliminary investigation of compound-specific isotope analysis (CSIA) of diesel fuels to evaluate whether the technique could distinguish between the diesel samples from different sources/locations. The ability to differentiate or correlate diesel samples could be valuable for detecting fuel tax evasion schemes. Two fractionation techniques were used to isolate the n-alkanes from the fuel. Both ?13C and ?D values for the n-alkanes were then determined by CSIA in each sample. Plots of ?D versus ?13C with sample n-alkane points connected in order of increasing carbon number gave well separated clusters with characteristic shapes for each sample. Principal components analysis (PCA) with ?13C, ?D, or combined ?13C and ?D data on the yielded scores plots that could clearly differentiate the samples, thereby demonstrating the potential of this approach for fingerprinting fuel samples using the ?13C and ?D values.

Harvey, Scott D.; Jarman, Kristin H.; Moran, James J.; Sorensen, Christina M.; Wright, Bob W.

2011-09-15T23:59:59.000Z

316

New approaches for the chemical and physical characterization of aerosols using a single particle mass spectrometry based technique  

E-Print Network [OSTI]

2004]. For example, anthraquinone, has a molecular weight (of 208, and methyl-anthraquinone has a MW of 222. However,

Spencer, Matthew Todd

2007-01-01T23:59:59.000Z

317

Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 1: Fine Particle Composition and Organic Source Apportionment  

SciTech Connect (OSTI)

Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identifies three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning.

Aiken, Allison; Salcedo, D.; Cubison, Michael J.; Huffman, J.; DeCarlo, Peter; Ulbrich, Ingrid M.; Docherty, Kenneth S.; Sueper, D. T.; Kimmel, Joel; Worsnop, Douglas R.; Trimborn, Achim; Northway, Megan; Stone, Elizabeth A.; Schauer, James J.; Volkamer, Rainer M.; Fortner, Edward; de Foy, B.; Wang, Jian; Laskin, Alexander; Shutthanandan, V.; Zheng, Junsheng; Zhang, Renyi; Gaffney, Jeffrey S.; Marley, Nancy A.; Paredes-Miranda, Guadalupe L.; Arnott, W. P.; Molina, Luisa T.; Sosa, G.; Jimenez, Jose L.

2009-09-11T23:59:59.000Z

318

PILOT_PROTEIN: Identification of Unmodified and Modified Proteins via High-Resolution Mass Spectrometry and Mixed-Integer Linear  

E-Print Network [OSTI]

accuracy with a lower false positive rate. All materials are freely available to the scientific community and protein identification and can help reduce the number of false positive resulPILOT_PROTEIN: Identification of Unmodified and Modified Proteins via High-Resolution Mass

Shorter, James

319

and Ion Processes ELSEVIER International Journal of Mass Spectrometry and lon Processes 167/168 (1997) 637-647  

E-Print Network [OSTI]

/168 (1997) 637-647 Microsolvation of the ammonium ion in argon: infrared spectra of NH --Arn complexes (n Received 25 November 1996; accepted 2 June 1997 Abstract Infrared spectra of mass selected NH~-Ar, (n = 1 of the tetrahedral monomer. © 1997 Elsevier Science B.V. © 1997 Elsevier Science B.V. Keywords: Ab initio studies

Nizkorodov, Sergey

320

Analysis on the Go: Quantitation of Drugs of Abuse in Dried Urine with Digital Microfluidics and Miniature Mass Spectrometry  

E-Print Network [OSTI]

Analysis on the Go: Quantitation of Drugs of Abuse in Dried Urine with Digital Microfluidics the development of a method coupling microfluidics and a miniature mass spectrometer, applied to quantitation of drugs of abuse in urine. A custom digital microfluidic system was designed to deliver droplets

Zandstra, Peter W.

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Size-selected 2, 5, and 10 nm gold nanoparticles for laser desorption/ionization mass spectrometry  

E-Print Network [OSTI]

, as subtle changes in the solution environment can result in subsequent changes in the mass spectra. A thorough evaluation of the parameters that affect desorption/ionization of peptides is presented here, and these parameters include: (i) AuNP-to...

Stumpo, Katherine Anne

2009-05-15T23:59:59.000Z

322

Applications of High-Resolution Electrospray Ionization Mass Spectrometry to Measurements of Average Oxygen to Carbon Ratios in Secondary Organic Aerosols  

SciTech Connect (OSTI)

The applicability of high resolution electrospray ionization mass spectrometry (HR ESI-MS) to measurements of the average oxygen to carbon ratio (O/C) in organic aerosols was investigated. Solutions with known average O/C containing up to 10 standard compounds representative of secondary organic aerosol (SOA) were analyzed and corresponding electrospray ionization efficiencies were quantified. The assumption of equal ionization efficiency commonly used in estimating O/C ratios of organic aerosols was found to be reasonably accurate. We found that the accuracy of the measured O/C ratios increases by averaging the values obtained from both (+) and (-) modes. A correlation was found between the ratio of the ionization efficiencies in the positive and negative ESI modes with the octanol-water partition constant, and more importantly, with the compound's O/C. To demonstrate the utility of this correlation for estimating average O/C values of unknown mixtures, we analyzed the ESI (+) and ESI (-) data for SOA produced by oxidation of limonene and isoprene and compared to online O/C measurements using an aerosol mass spectrometer (AMS). This work demonstrates that the accuracy of the HR ESI-MS methods is comparable to that of the AMS, with the added benefit of molecular identification of the aerosol constituents.

Bateman, Adam P.; Laskin, Julia; Laskin, Alexander; Nizkorodov, Sergey

2012-07-02T23:59:59.000Z

323

Accelerated Analyte Uptake on Single Beads in Microliter-scale Batch Separations using Acoustic Streaming: Plutonium Uptake by Anion Exchange for Analysis by Mass Spectrometry  

SciTech Connect (OSTI)

The use of acoustic streaming as a non-contact mixing platform to accelerate mass transport-limited diffusion processes in small volume heterogeneous reactions has been investigated. Single bead anion exchange of plutonium at nanomolar and sub-picomolar concentrations in 20 microliter liquid volumes was used to demonstrate the effect of acoustic mixing. Pu uptake rates on individual ~760 micrometer diameter AG 1x4 anion exchange resin beads were determined using acoustic mixing and compared with Pu uptake rates achieved by static diffusion alone. An 82 MHz surface acoustic wave (SAW) device was placed in contact with the underside of a 384-well microplate containing flat-bottomed semiconical wells. Acoustic energy was coupled into the solution in the well, inducing acoustic streaming. Pu uptake rates were determined by the plutonium remaining in solution after specific elapsed time intervals, using liquid scintillation counting (LSC) for nanomolar concentrations and thermal ionization mass spectrometry (TIMS) analysis for the sub-picomolar concentration experiments. It was found that this small batch uptake reaction could be accelerated by a factor of about five-fold or more, depending on the acoustic power applied.

Paxton, Walter F.; O'Hara, Matthew J.; Peper, Shane M.; Petersen, Steven L.; Grate, Jay W.

2008-06-01T23:59:59.000Z

324

Standard test method for analysis of urine for uranium-235 and uranium-238 isotopes by inductively coupled plasma-mass spectrometry  

E-Print Network [OSTI]

1.1 This test method covers the determination of the concentration of uranium-235 and uranium-238 in urine using Inductively Coupled Plasma-Mass Spectrometry. This test method can be used to support uranium facility bioassay programs. 1.2 This method detection limits for 235U and 238U are 6 ng/L. To meet the requirements of ANSI N13.30, the minimum detectable activity (MDA) of each radionuclide measured must be at least 0.1 pCi/L (0.0037 Bq/L). The MDA translates to 47 ng/L for 235U and 300 ng/L for 238U. Uranium– 234 cannot be determined at the MDA with this test method because of its low mass concentration level equivalent to 0.1 pCi/L. 1.3 The digestion and anion separation of urine may not be necessary when uranium concentrations of more than 100 ng/L are present. 1.4 Units—The values stated in picoCurie per liter units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1....

American Society for Testing and Materials. Philadelphia

2010-01-01T23:59:59.000Z

325

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)

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.

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

2014-08-21T23:59:59.000Z

326

CHEMICAL EVOLUTION IN HIGH-MASS STAR-FORMING REGIONS: RESULTS FROM THE MALT90 SURVEY  

SciTech Connect (OSTI)

The chemical changes of high-mass star-forming regions provide a potential method for classifying their evolutionary stages and, ultimately, ages. In this study, we search for correlations between molecular abundances and the evolutionary stages of dense molecular clumps associated with high-mass star formation. We use the molecular line maps from Year 1 of the Millimetre Astronomy Legacy Team 90 GHz (MALT90) Survey. The survey mapped several hundred individual star-forming clumps chosen from the ATLASGAL survey to span the complete range of evolution, from prestellar to protostellar to H II regions. The evolutionary stage of each clump is classified using the Spitzer GLIMPSE/MIPSGAL mid-IR surveys. Where possible, we determine the dust temperatures and H{sub 2} column densities for each clump from Herschel/Hi-GAL continuum data. From MALT90 data, we measure the integrated intensities of the N{sub 2}H{sup +}, HCO{sup +}, HCN and HNC (1-0) lines, and derive the column densities and abundances of N{sub 2}H{sup +} and HCO{sup +}. The Herschel dust temperatures increase as a function of the IR-based Spitzer evolutionary classification scheme, with the youngest clumps being the coldest, which gives confidence that this classification method provides a reliable way to assign evolutionary stages to clumps. Both N{sub 2}H{sup +} and HCO{sup +} abundances increase as a function of evolutionary stage, whereas the N{sub 2}H{sup +} (1-0) to HCO{sup +} (1-0) integrated intensity ratios show no discernable trend. The HCN (1-0) to HNC(1-0) integrated intensity ratios show marginal evidence of an increase as the clumps evolve.

Hoq, Sadia; Jackson, James M.; Foster, Jonathan B.; Sanhueza, Patricio; Claysmith, Christopher [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Guzmán, Andrés [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Whitaker, J. Scott [Physics Department, Boston University, Boston, MA 02215 (United States); Rathborne, Jill M. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Epping, NSW (Australia); Vasyunina, Tatiana; Vasyunin, Anton, E-mail: shoq@bu.edu, E-mail: jackson@bu.edu, E-mail: patricio@bu.edu, E-mail: claysmit@bu.edu, E-mail: jonathan.b.foster@yale.edu, E-mail: aguzmanf@cfa.harvard.edu, E-mail: scott@bu.edu, E-mail: rathborne@csiro.au, E-mail: tv3h@virginia.edu, E-mail: aiv3f@virginia.edu [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States)

2013-11-10T23:59:59.000Z

327

Charge and frequency resolved isochronous mass spectrometry in storage rings: First direct mass measurement of the short-lived neutron-deficient $^{51}$Co nuclide  

E-Print Network [OSTI]

Revolution frequency measurements of individual ions in storage rings require sophisticated timing detectors. One of common approaches for such detectors is the detection of secondary electrons released from a thin foil due to penetration of the stored ions. A new method based on the analysis of intensities of secondary electrons was developed which enables determination of the charge of each ion simultaneously with the measurement of its revolution frequency. Although the mass-over-charge ratios of $^{51}$Co$^{27+}$ and $^{34}$Ar$^{18+}$ ions are almost identical, and therefore, the ions can not be resolved in a storage ring, by applying the new method the mass excess of the short-lived $^{51}$Co is determined for the first time to be ME($^{51}$Co)=-27342(48) keV. Shell-model calculations in the $fp$-shell nuclei compared to the new data indicate the need to include isospin-nonconserving forces.

P. Shuai; H. S. Xu; X. L. Tu; Y. H. Zhang; B. H. Sun; Yu. A. Litvinov; X. L. Yan; K. Blaum; M. Wang; X. H. Zhou; J. J. He; Y. Sun; K. Kaneko; Y. J. Yuan; J. W. Xia; J. C. Yang; G. Audi; X. C. Chen; G. B. Jia; Z. G. Hu; X. W. Ma; R. S. Mao; B. Mei; Z. Y. Sun; S. T. Wang; G. Q. Xiao; X. Xu; T. Yamaguchi; Y. Yamaguchi; Y. D. Zang; H. W. Zhao; T. C. Zhao; W. Zhang; W. L. Zhan

2014-04-08T23:59:59.000Z

328

Determination of the Relative Amount of Fluorine in Uranium Oxyfluoride Particles using Secondary Ion Mass Spectrometry and Optical Spectroscopy  

SciTech Connect (OSTI)

Both nuclear forensics and environmental sampling depend upon laboratory analysis of nuclear material that has often been exposed to the environment after it has been produced. It is therefore important to understand how those environmental conditions might have changed the chemical composition of the material over time, particularly for chemically sensitive compounds. In the specific case of uranium enrichment facilities, uranium-bearing particles stem from small releases of uranium hexafluoride, a highly reactive gas that hydrolyzes upon contact with moisture from the air to form uranium oxyfluoride (UO{sub 2}F{sub 2}) particles. The uranium isotopic composition of those particles is used by the International Atomic Energy Agency (IAEA) to verify whether a facility is compliant with its declarations. The present study, however, aims to demonstrate how knowledge of time-dependent changes in chemical composition, particle morphology and molecular structure can contribute to an even more reliable interpretation of the analytical results. We prepared a set of uranium oxyfluoride particles at the Institute for Reference Materials and Measurements (IRMM, European Commission, Belgium) and followed changes in their composition, morphology and structure with time to see if we could use these properties to place boundaries on the particle exposure time in the environment. Because the rate of change is affected by exposure to UV-light, humidity levels and elevated temperatures, the samples were subjected to varying conditions of those three parameters. The NanoSIMS at LLNL was found to be the optimal tool to measure the relative amount of fluorine in individual uranium oxyfluoride particles. At PNNL, cryogenic laser-induced time-resolved U(VI) fluorescence microspectroscopy (CLIFS) was used to monitor changes in the molecular structure.

Kips, R; Kristo, M J; Hutcheon, I D; Amonette, J; Wang, Z; Johnson, T; Gerlach, D; Olsen, K B

2009-05-29T23:59:59.000Z

329

Rapid characterization of lignocellulosic feedstocks for fuels and chemicals: Molecular beam mass spectrometric approach  

SciTech Connect (OSTI)

Rapid characterization of biomass feedstocks has a pivotal role in the development of biomass energy because of the large number of samples that must be analyzed due to the diversity of biomass feedstocks and the significant differences in the chemical and physical properties of these feedstocks. Several biomass feedstocks (herbaceous, woody, and agricultural residues) were screened for the effects of storage, season of harvest, geographic location, clonal, and species variation on the pyrolysis products of the feed stocks. For herbaceous species such as sericea lespedeza, the season of harvest had a significant effect on the pyrolysis products. Effects of clonal variation on the composition of hybrid poplar feedstocks was easily discerned with the molecular beam mass spectrometric analysis. The effect of geographic location on the poplar clones pyrolysis products was minimal. However in the case of switchgrass, varietal influence on the pyrolysis products was minimal, but where the plant was grown had a strong influence on the pyrolysis products of the feedstock. Significant differences because of species variation could also be shown from the pyrolysis products of various biomass feedstocks. The influence of storage time on biomass samples stored outside in the open could also be discerned from the pyrolysis products of the feedstocks. The differences noted in the pyrolysis products of the feedstocks were noted for samples which were significantly degraded during storage either through the action of microflora or weathering.

Agblevor, F.A.; Davis, M.F. [National Renewable Energy Lab., Golden, CO (United States)

1996-12-31T23:59:59.000Z

330

Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) - Part 1: Fine particle composition and organic source apportionment  

SciTech Connect (OSTI)

Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM{sub 2.5} chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM{sub 2.5} emissions by a factor of {approx}4, and it is {approx}16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is at least an order-of-magnitude larger than in the inventory.

Aiken, A.C.; Wang, J.; Salcedo, D.; Cubison, M. J.; Huffman, J. A.; DeCarlo, P. F.; Ulbrich, I. M.; Docherty, K. S.; Sueper, D.; Kimmel, J. R.; Worsnop, D. R.; Trimborn, A.; Northway, M.; Stone, E. A.; Schauer, J. J.; Volkamer, R. M.; Fortner, E.; de Foy, B.; Laskin, A.; Shutthanandan, V.; Zheng, J.; Zhang, R.; Gaffney, J.; Marley, N. A.; Paredes-Miranda, G.; Arnott, W. P.; Molina, L. T.; Sosa, G.; Jimenez, J. L.

2009-09-01T23:59:59.000Z

331

Chemical Analysis of Complex Organic Mixtures Using Reactive...  

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

Mass Spectrometry. Abstract: Reactive nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was utilized for the analysis of...

332

Soluble arsenic and selenium species in fly ash/organic waste-amended soils using ion chromatography-inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

Mixing coal fly ash with an organic waste increases macronutrient content and may make land application of fly ash a viable disposal alternative. However, trace element chemistry of these mixed waste products warrants investigation. Speciation of As and Se in soil solutions of fly ash-, poultry litter- and sewage sludge-amended soils was determined over a 10-day period by ion chromatography coupled to inductively coupled plasma mass spectrometry (IC-ICP-MS). Detection limits were 0.031, 0.028, 0.051, 0.161, 0.497, and 0.660 {micro}g L{sup {minus}1} for dimethylarsinate (DMA), As(III), monomethylarsonate (MMA), As(V), Se(IV), and Se(VI), respectively. Arsenic was highly water-soluble from poultry litter and appeared to be predominantly As(V). Arsenic(V) was the predominant species in soil amended with two fly ashes. Application of fly ash/poultry litter mixtures increased As solubility and led to the prevalence of DMA as the major As species. DMA concentrations of these soil solutions decreased rapidly over the sampling period relative to As(V), suggesting that DMA readily underwent mineralization in the soil solution. Se(VI) was the predominant soluble Se species in all treatments indicating rapid oxidation of Se(IV) initially solubilized from the fly ashes.

Jackson, B.P.; Miller, W.P. [Univ. of Georgia, Athens, GA (United States). Dept. of Crop and Soil Sciences] [Univ. of Georgia, Athens, GA (United States). Dept. of Crop and Soil Sciences

1999-01-15T23:59:59.000Z

333

Gadolinium speciation with Tetradentate, N-donor extractants for minor actinide/lanthanide separation: an XRD, mass spectrometry and EPR study  

SciTech Connect (OSTI)

The hydrophobic organic molecules CyMe{sub 4}-BTPhen (1) and CyMe{sub 4}-BTBP (2) have been developed and tuned over many years to be able to separate the trivalent actinides from the trivalent lanthanides (Ln) selectively in bi-phasic solvent extraction processes for the separation of the long-lived radio-toxic minor actinides from spent nuclear fuel. The ability of these N-donor ligands to perform this separation is poorly understood, as is their speciation with the metal ions when extracted into the organic phase. Our previous work has shown Ln{sup 3+} speciation to be largely 1:2 Ln:L in nature with another small molecule, either water or nitrate, occupying a cavity between the tetradentate bound N-donor ligands. The identity of the small molecule changes across the lanthanide series, and here we continue investigations into this speciation. Complexes of these N-donor ligands with Gd{sup 3+} have been synthesised and characterised by X-ray crystallography, mass spectrometry and EPR spectroscopy. We show that the N-donor ligands have no effect on the electronic configuration of Gd{sup 3+} and that the lanthanide contraction with the steric rigidity of the N-donor ligand appears to determine the size of the cavity between the coordinated ligands. This in turn appears to control the identity of the small molecule on the ninth site in the 1:2 Gd:L species. (authors)

Whittaker, D.M. [School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Sharrad, C.A. [School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Research Centre for Radwaste and Decommissioning, Dalton Nuclear Institute, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Sproules, S. [Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2013-07-01T23:59:59.000Z

334

Analysis of Nitro-Polycyclic Aromatic Hydrocarbons in Conventional Diesel and Fischer--Tropsch Diesel Fuel Emissions Using Electron Monochromator-Mass Spectrometry  

SciTech Connect (OSTI)

The presence of nitro-polycyclic aromatic hydrocarbons (NPAHs) in diesel fuel emissions has been studied for a number of years predominantly because of their contribution to the overall health and environmental risks associated with these emissions. Electron monochromator-mass spectrometry (EM-MS) is a highly selective and sensitive method for detection of NPAHs in complex matrixes, such as diesel emissions. Here, EM-MS was used to compare the levels of NPAHs in fuel emissions from conventional (petroleum) diesel, ultra-low sulfur/low-aromatic content diesel, Fischer-Tropsch synthetic diesel, and conventional diesel/synthetic diesel blend. The largest quantities of NPAHs were detected in the conventional diesel fuel emissions, while the ultra-low sulfur diesel and synthetic diesel fuel demonstrated a more than 50% reduction of NPAH quantities when compared to the conventional diesel fuel emissions. The emissions from the blend of conventional diesel with 30% synthetic diesel fuel also demonstrated a more than 30% reduction of the NPAH content when compared to the conventional diesel fuel emissions. In addition, a correlation was made between the aromatic content of the different fuel types and NPAH quantities and between the nitrogen oxides emissions from the different fuel types and NPAH quantities. The EM-MS system demonstrated high selectivity and sensitivity for detection of the NPAHs in the emissions with minimal sample cleanup required.

Havey, C. D.; McCormick, R. L.; Hayes, R. R.; Dane, A. J.; Voorhees, K. J.

2006-01-01T23:59:59.000Z

335

Probing Molecular Associations of Field-Collected and Laboratory-Generated SOA with Nano-DESI High-Resolution Mass Spectrometry  

SciTech Connect (OSTI)

Aerosol samples from the 2010 CalNex field study in Bakersfield (BF) and Los Angeles (LA) were analyzed using positive mode nanospray-desorption electrospray ionization mass spectrometry (nano-DESI-MS). Secondary organic aerosol (SOA) produced in a photochemical chamber by photooxidation of diesel (DSL) fuel and isoprene (ISO) under humid, high-NOx conditions, was analyzed for comparison. Three groups of organic compounds with zero, one, or two nitrogen atoms in their molecular formulas (0N, 1N, 2N) were compared in detail. The composition of ambient SOA exhibited greater overlap with DSL than with ISO. The overlap of the chamber experiments with the BF data was relatively consistent throughout the day while the overlap with LA data increased significantly in the noon-6pm sample, consistent with the SOA plume arriving from downtown Los Angeles. BF samples were more oxidized, contained more organic nitrogen, and had more overlap with the chamber data compared to LA samples. The addition of gaseous ammonia (NH3) to the DSL experiment was necessary to generate many of the 2N compounds observed in BF. This analysis demonstrates that DSL and ISO were important sources but cannot account for all of the observed ambient compounds indicating that other sources of organics were also likely important.

O'Brien, Rachel E.; Nguyen, Tran B.; Laskin, Alexander; Laskin, Julia; Hayes, Patrick L.; Liu, Shang; Jimenez, Jose L.; Russell, Lynn M.; Nizkorodov, Sergey; Goldstein, Allen H.

2013-01-30T23:59:59.000Z

336

Atmospheric Amines and Ammonia Measured with a Chemical Ionization Mass Spectrometer (CIMS)  

SciTech Connect (OSTI)

We report ambient measurements of amines and ammonia with a fast response chemical ionization mass spectrometer (CIMS) in a Southeastern U.S. forest in Alabama and a moderately polluted Midwestern site during the summer. In the Alabama forest, mostly C3-amines (from pptv to tens of pptv) and ammonia (up to 2 ppbv) were detected on a daily basis. C3-amines and ammonia showed similar diurnal trends and temperature and wind direction dependences, and were not associated with transported CO and SO2 plumes. Consistent with temperature dependences, amine and ammonia in the gas and aerosol phases showed opposite diurnal trends, indicating gas-to-particle partitioning of amines and ammonia. Temperature dependences also imply reversible processes of amines and ammonia evaporation from soil surfaces in daytime and deposition of amines and ammonia to soil surfaces at nighttime. Various amines (C1-C6) at the pptv level were observed in the transported biomass burning plumes, showing that biomass burning can be a substantial source of amines in the Southeast U.S. At the moderately polluted Kent site, higher concentrations of amines (C1-C6, from pptv to tens of pptv) and ammonia (up to 6 ppbv) were detected. Diurnal variations of C1- to C3-amines and ammonia were correlated with the ambient temperature. C4- to C6-amines showed abrupt increases during the nighttime, suggesting that they were emitted from local sources. These abundant amines and ammonia may in part explain the frequent new particle formation events reported from Kent. Lower amine concentrations at the rural forested site highlight the importance of constraining anthropogenic sources of amines.

You, Y.; Kanawade, V. P.; de Gouw, J. A.; Guenther, Alex B.; Madronich, Sasha; Sierra-Hernandez, M. R.; Lawler, M.; Smith, James N.; Takahama, S.; Ruggeri, G.; Koss, A.; Olson, K.; Baumann, K.; Weber, R. J.; Nenes, A.; Guo, H.; Edgerton, Eric S.; Porcelli, L.; Brune, W. H.; Goldstein, Allen H.; Lee, S.-H

2014-11-19T23:59:59.000Z

337

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)

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 (300–630 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.

Leplat, N.; Rossi, M. J. [Laboratory of Atmospheric Chemistry (LAC), Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland)] [Laboratory of Atmospheric Chemistry (LAC), Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland)

2013-11-15T23:59:59.000Z

338

Studies of the combustion of coal/refuse derived fuels using thermogravimetric-Fourier transform infrared-mass spectrometry  

SciTech Connect (OSTI)

The materials used in this project included two bituminous coals, a medium molecular weight PVC resin, cellulose, and shredded newspaper. Analytical data for the samples are given. A TA Instruments Model 951 Thermogravimetric Analyzer (TG) interfaced to a Perkin Elmer 1650 Fourier Transform Infrared Spectrometer (FTIR) was used in this study. The horizontal quartz furnace of the TG was connected to the 10 cm gas cell of the FTIR using an insulated teflon tube heated to a temperature of 150{degrees}C. The TG was also interfaced to a VG Thermolab Mass Spectrometer (MS) using a fused silica capillary sampling tube heated to approximately 170{degrees}C. A teflon splitter divides the gases from the TG into two parts, one to the FTIR ({approximately}95%), and the other to the MS ({approximately}5%). A schematic of the TG-FTIR-MS system, is presented. In the TG experiments, all samples ({approximately}300 mg each) were heated in air (50 ML/min) at a rate of 10{degrees}C/min to 700{degrees}C. The spectra and profiles of gaseous species evolving from the TG system were recorded and analyzed by the TGA-FTIR-MS analytical system. The results of the experiments are given.

Lu, H.; Li, J.; Lloyd, W.G. [and others

1995-08-01T23:59:59.000Z

339

C60 Secondary Ion Fourier Transform Ion Cyclotron Resonance Mass...  

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

C60 Secondary Ion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. C60 Secondary Ion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. Abstract: Secondary...

340

A Hybrid Approach to Protein Differential Expression in Mass...  

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

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

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

E-Print Network 3.0 - alpha spectrometry 232u Sample Search Results  

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

for thermal ionization mass spectrometry (TIMS) and 800 mg for alpha spectrom- etry. Uranium-thorium TIMS... . Alpha spectrometry was performed at the University of Iowa....

342

Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry  

SciTech Connect (OSTI)

RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injection volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.

Bhandari, Deepak [ORNL] [ORNL; Kertesz, Vilmos [ORNL] [ORNL; Van Berkel, Gary J [ORNL] [ORNL

2013-01-01T23:59:59.000Z

343

Targeted Peptide Measurements in Biology and Medicine: Best Practices for Mass Spectrometry-based Assay Development Using a Fit-for-Purpose Approach  

SciTech Connect (OSTI)

Adoption of targeted mass spectrometry (MS) approaches such as multiple reaction monitoring (MRM) to study biological and biomedical questions is well underway in the proteomics community. Successful application depends on the ability to generate reliable assays that uniquely and confidently identify target peptides in a sample. Unfortunately, there is a wide range of criteria being applied to say that an assay has been successfully developed. There is no consensus on what criteria are acceptable and little understanding of the impact of variable criteria on the quality of the results generated. Publications describing targeted MS assays for peptides frequently do not contain sufficient information for readers to establish confidence that the tests work as intended or to be able to apply the tests described in their own labs. Guidance must be developed so that targeted MS assays with established performance can be made widely distributed and applied by many labs worldwide. To begin to address the problems and their solutions, a workshop was held at the National Institutes of Health with representatives from the multiple communities developing and employing targeted MS assays. Participants discussed the analytical goals of their experiments and the experimental evidence needed to establish that the assays they develop work as intended and are achieving the required levels of performance. Using this “fit-for-purpose” approach, the group defined three tiers of assays distinguished by their performance and extent of analytical characterization. Computational and statistical tools useful for the analysis of targeted MS results were described. Participants also detailed the information that authors need to provide in their manuscripts to enable reviewers and readers to clearly understand what procedures were performed and to evaluate the reliability of the peptide or protein quantification measurements reported. This paper presents a summary of the meeting and recommendations. Molecular & Cellular Proteomics 13: 10.1074/mcp.M113.036095, 907–917, 2014.

Carr, Steven A.; Abbateillo, Susan E.; Ackermann, Bradley L.; Borchers, Christoph H.; Domon, Bruno; Deutsch, Eric W.; Grant, Russel; Hoofnagle, Andrew N.; Huttenhain, Ruth; Koomen, John M.; Liebler, Daniel; Liu, Tao; MacLean, Brendan; Mani, DR; Mansfield, Elizabeth; Neubert, Hendrik; Paulovich, Amanda G.; Reiter, Lukas; Vitek, Olga; Aebersold, Ruedi; Anderson, Leigh N.; Bethem, Robert; Blonder, Josip; Boja, Emily; Botelho, Julianne; Boyne, Michael; Bradshaw, Ralph A.; Burlingame, Alma S.; Chan, Daniel W.; Keshishian, Hasmik; Kuhn, Eric; Kingsinger, Christopher R.; Lee, Jerry S.; Lee, Sang-Won; Moritz, Robert L.; Oses-Prieto, Juan; Rifai, Nader; Ritchie, James E.; Rodriguez, Henry; Srinivas, Pothur R.; Townsend, Reid; Van Eyk , Jennifer; Whiteley, Gordon; Wiita, Arun; Weintraub, Susan

2014-01-14T23:59:59.000Z

344

Sandia National Laboratories: mass spectrometry  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1developmentturbine bladelifetime is the cumulative time underpower measurementmass

345

Quantification of absorption, retention and elimination of two different oral doses of vitamin A in Zambian boys using accelerator mass spectrometry  

SciTech Connect (OSTI)

A recent survey indicated that high-dose vitamin A supplements (HD-VAS) had no apparent effect on vitamin A (VA) status of Zambian children <5 y of age. To explore possible reasons for the lack of response to HD-VAS among Zambian children, we quantified the absorption, retention, and urinary elimination of either a single HDVAS (60 mg) or a smaller dose of stable isotope (SI)-labeled VA (5 mg), which was used to estimate VA pool size, in 3-4 y old Zambian boys (n = 4 for each VA dose). A 25 nCi tracer dose of [{sup 14}C{sub 2}]-labeled VA was co-administered with the HD-VAS or SI-labeled VA, and 24-hr stool and urine samples were collected for 3 and 7 consecutive days, respectively, and 24-hr urine samples at 4 later time points. Accelerator Mass Spectrometry (AMS) was used to measure the cumulative excretion of {sup 14}C in stool and urine 3d after dosing to estimate, respectively, absorption and retention of the VAS and SI-labeled VA. The urinary elimination rate (UER) was estimated by plotting {sup 14}C in urine vs. time, and fitting an exponential equation to the data. Estimates of mean absorption, retention and the UER were 83.8 {+-} 7.1%, 76.3 {+-} 6.7%, and 1.9 {+-} 0.6%/d, respectively, for the HD-VAS and 76.5 {+-} 9.5%, 71.1 {+-} 9.4%, and 1.8 {+-} 1.2%/d, respectively for the smaller dose of SI-labeled VA. Estimates of absorption, retention and the UER did not differ by size of the VA dose administered (P=0.26, 0.40, 0.88, respectively). Estimated absorption and retention were negatively associated with reported fever (P=0.011) and malaria (P =0.010). HD-VAS and SI-labeled VA were adequately absorbed, retained and utilized in apparently healthy Zambian preschool-age boys, although absorption and retention may be affected by recent infections.

Aklamati, E K; Mulenga, M; Dueker, S R; Buchholz, B A; Peerson, J M; Kafwembe, E; Brown, K H; Haskell, M J

2009-10-12T23:59:59.000Z

346

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Free Acid by Titration in an Oxalate Solution 8 to 15 Free Acid by Iodate Precipitation-Potentiometric Titration Test Method 16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33 Thorium by Thorin Spectrophotometric Test Method 34 to 42 Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50 Impurities by ICP-AES Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58 Fluoride by Distillation-Spectrophotometric Test Method 59 to 66 Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74 Isotopic Composition by Mass Spectrom...

American Society for Testing and Materials. Philadelphia

2010-01-01T23:59:59.000Z

347

Mass densification and defect restoration in chemical vapor deposition silicon dioxide film using Ar plasma excited by microwave  

SciTech Connect (OSTI)

Silicon dioxide (SiO{sub 2}) films formed by chemical vapor deposition (CVD) have been treated with Ar plasma excited by microwave. The changes of the mass densities, carrier trap densities, and thicknesses of the CVD-SiO{sub 2} films with the Ar plasma treatments were investigated. The mass density depth profiles were estimated with X-Ray Reflectivity (XRR) analysis using synchrotron radiation. The densities of carrier trap centers due to defects of Si-O bond network were estimated with X-ray Photoelectron Spectroscopy (XPS) time-dependent measurement. The changes of the thicknesses due to the oxidation of Si substrates were estimated with the XRR and XPS. The mass densities of the CVD-SiO{sub 2} films are increased by the Ar plasma treatments. The carrier trap densities of the films are decreased by the treatments. The thicknesses of the films are not changed by the treatments. It has been clarified that the mass densification and defect restoration in the CVD-SiO{sub 2} films are caused by the Ar plasma treatments without the oxidation of the Si substrates.

Kawase, Kazumasa, E-mail: Kawase.Kazumasa@ak.MitsubishiElectric.co.jp; Motoya, Tsukasa; Uehara, Yasushi [Advanced Technology R and D Center, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-honmachi, Amagasaki, Hyogo 661-8661 (Japan); Teramoto, Akinobu; Suwa, Tomoyuki; Ohmi, Tadahiro [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

2014-09-01T23:59:59.000Z

348

Chemical Abundances of the Highly Obscured Galactic Globular Clusters 2MASS GC02 and Mercer 5  

E-Print Network [OSTI]

We present the first high spectral resolution abundance analysis of two newly discovered Galactic globular clusters, namely Mercer 5 and 2MASS GC02 residing in regions of high interstellar reddening in the direction of the Galactic center. The data were acquired with the Phoenix high-resolution near-infrared echelle spectrograph at Gemini South (R~50000) in the 15500.0 A - 15575.0 A spectral region. Iron, Oxygen, Silicon, Titanium and Nickel abundances were derived for two red giant stars, in each cluster, by comparing the entire observed spectrum with a grid of synthetic spectra generated with MOOG. We found [Fe/H] values of -0.86 +/- 0.12 and -1.08 +/- 0.13 for Mercer 5 and 2MASS GC02 respectively. The [O/Fe], [Si/Fe] and [Ti/Fe] ratios of the measured stars of Mercer 5 follow the general trend of both bulge field and cluster stars at this metallicity, and are enhanced by > +0.3. The 2MASS GC02 stars have relatively lower ratios, but still compatible with other bulge clusters. Based on metallicity and abund...

Penaloza, Francisco; Vasquez, Sergio; Borissova, Jura; Kurtev, Radostin; Zoccali, Manuela

2015-01-01T23:59:59.000Z

349

Magnetic fields and chemical peculiarities of the very young intermediate-mass binary system HD 72106  

E-Print Network [OSTI]

The recently discovered magnetic Herbig Ae and Be stars may provide qualitatively new information about the formation and evolution of magnetic Ap and Bp stars. We have performed a detailed investigation of one particularly interesting binary system with a Herbig Ae secondary and a late B-type primary possessing a strong, globally ordered magnetic field. Twenty high-resolution Stokes V spectra of the system were obtained with the ESPaDOnS instrument mounted on the CFHT. In these observations we see clear evidence for a magnetic field in the primary, but no evidence for a magnetic field in the secondary. A detailed abundance analysis was performed for both stars, revealing strong chemical peculiarities in the primary and normal chemical abundances in the secondary. The primary is strongly overabundant in Si, Cr, and other iron-peak elements, as well as Nd, and underabundant in He. The primary therefore appears to be a very young Bp star. In this context, line profile variations of the primary suggest non-unifo...

Folsom, C P; Kochukhov, O; Alecian, E; Catala, C; Bagnulo, S; Böhm, T; Bouret, J -C; Donati, J -F; Grunhut, J; Hanes, D A; Landstreet, J D

2008-01-01T23:59:59.000Z

350

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

American Society for Testing and Materials. Philadelphia

1999-01-01T23:59:59.000Z

351

Device for collecting chemical compounds and related methods  

DOE Patents [OSTI]

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine

2013-01-01T23:59:59.000Z

352

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

SciTech Connect (OSTI)

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 ensemble. This would cause the analysis to be skewed. The use of a gelatin substrate allows the ablation a particle ensemble without disturbing other particles or the gelatin surface. A method to trap and ablate particles on filter paper using collodion was also investigated. The laser was used to dig through the collodion layer and into the particle ensemble. Both of these methods fix particles to allow spatial resolution of the particle ensembles. The use of vanillic acid as a possible enhancement to ablation was also studied. A vanillic acid coating of the particles fixed on top of the gelatin substrate was not found to have any positive effect on either signal intensity or precision. The mixing of vanillic acid in the collodion solution used to coat the filter paper increased ablation signal intensity by a factor of 4 to 5. There was little effect on precision, though. The collodion on filter paper method and the gelatin method of resolving particles have shown themselves to be possible tools in fighting proliferation of nuclear weapons and material. Future applications of LA-ICP-MS are only limited by the imagination of the investigator. Any material that can be ablated and aerosolized is a potential material for analysis by LA-ICP-MS. Improvements in aerosol transport, ablation chamber design, and laser focusing can make possible the ablation and analysis of very small amounts of material. This may perhaps lead to more possible uses in forensics. A similar method to the one used in Chapter 3 could perhaps be used to match drug residue to the place of origin. Perhaps a link could be made based on the elements leached from the soil by plants used to make drugs. This may have a specific pattern based on where the plant was grown. Synthetic drugs are produced in clandestine laboratories that are often times very dirty. The dust, debris, and unique materials in the lab environment could create enough variance to perhaps match drugs produced there to samples obtained off the street. Even if the match was not strong enough to be evidence, the knowledge that many sa

Messerly, Joshua D.

2008-08-26T23:59:59.000Z

353

Chemical analysis of biomass fast pyrolysis oils  

SciTech Connect (OSTI)

This paper reviews the development of the field of chemical analysis of biomass fast pyrolysis oils. The techniques applied to pyrolysis oil analysis are reviewed including proximate and ultimate analysis, water (moisture) analysis, and chemical component analysis by various forms of chromatography, solvent separations, and spectrophotometric analyses, like infrared and ultraviolet. Advanced analytical techniques such as nuclear magnetic resonance and molecular beam -- mass spectrometry are also discussed. This paper reviews and compares the methods and the results of the analyses. The advantages and shortcomings of the various methods applied are identified. Comparisons derived from the IEA Round Robin are incorporated.

Elliott, D.C.

1994-09-01T23:59:59.000Z

354

Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids  

SciTech Connect (OSTI)

Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

Charles J Werth; Albert J Valocchi, Hongkyu Yoon

2011-05-21T23:59:59.000Z

355

High Mass Accuracy and High Mass Resolving Power FT-ICR Secondary...  

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

High Mass Accuracy and High Mass Resolving Power FT-ICR Secondary Ion Mass Spectrometry for Biological Tissue Imaging. High Mass Accuracy and High Mass Resolving Power FT-ICR...

356

Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets  

E-Print Network [OSTI]

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 ?g/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 ?g. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 ?g. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

American Society for Testing and Materials. Philadelphia

1999-01-01T23:59:59.000Z

357

Mexico City Aerosol Analysis During Milagro Using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0) - Part 1: Fine Particle Composition and Organic Source Apportionment.  

E-Print Network [OSTI]

Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS) and complementary instrumentation. Positive ...

Aiken, A. C.

358

New constraints on methane fluxes and rates of anaerobic methane oxidation in a Gulf of Mexico brine pool via in situ mass spectrometry  

E-Print Network [OSTI]

New constraints on methane fluxes and rates of anaerobic methane oxidation in a Gulf of Mexico Keywords: Methane flux Mass spectrometer Brine pool Methane oxidation Gulf of Mexico a b s t r a c t Deep heterogeneity. In particular, biogeochemical fluxes of volatiles such as methane remain largely unconstrained

Girguis, Peter R.

359

Method for quantitative determination and separation of trace amounts of chemical elements in the presence of large quantities of other elements having the same atomic mass  

DOE Patents [OSTI]

Photoionization via autoionizing atomic levels combined with conventional mass spectroscopy provides a technique for quantitative analysis of trace quantities of chemical elements in the presence of much larger amounts of other elements with substantially the same atomic mass. Ytterbium samples smaller than 10 ng have been detected using an ArF* excimer laser which provides the atomic ions for a time-of-flight mass spectrometer. Elemental selectivity of greater than 5:1 with respect to lutetium impurity has been obtained. Autoionization via a single photon process permits greater photon utilization efficiency because of its greater absorption cross section than bound-free transitions, while maintaining sufficient spectroscopic structure to allow significant photoionization selectivity between different atomic species. Separation of atomic species from others of substantially the same atomic mass is also described.

Miller, C.M.; Nogar, N.S.

1982-09-02T23:59:59.000Z

360

Chemical Consequences of Heme Distortion and the Role of Heme Distortion in Signal Transduction of H-NOX Proteins  

E-Print Network [OSTI]

scintillation liquid (MP Biomedicals) and measured with LS 650 (Beckman Coulter). Mass Spectrometry.

Olea, Jr., Charles

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

LipidMiner: A Software for Automated Identification and Quantification of Lipids from Multiple Liquid Chromatography-Mass Spectrometry Data Files  

SciTech Connect (OSTI)

We have developed a tool for automated, high-throughput analysis of LC-MS/MS data files, which greatly simplifies LC-MS based lipidomics analysis. Our results showed that LipidMiner is accurate and comprehensive in identification and quantification of lipid molecular species. In addition, the workflow implemented in LipidMiner is not limited to identification and quantification of lipids. If a suitable metabolite library is implemented in the library matching module, LipidMiner could be reconfigured as a tool for general metabolomics data analysis. It is of note that LipidMiner currently is limited to singly charged ions, although it is adequate for the purpose of lipidomics since lipids are rarely multiply charged,[14] even for the polyphosphoinositides. LipidMiner also only processes file formats generated from mass spectrometers from Thermo, i.e. the .RAW format. In the future, we are planning to accommodate file formats generated by mass spectrometers from other predominant instrument vendors to make this tool more universal.

Meng, Da; Zhang, Qibin; Gao, Xiaoli; Wu, Si; Lin, Guang

2014-04-30T23:59:59.000Z

362

Quadrupole mass spectrometry and time-of-flight analysis of ions resulting from 532 nm pulsed laser ablation of Ni, Al, and ZnO targets  

SciTech Connect (OSTI)

This work describes the design and validation of an instrument to measure the kinetic energies of ions ejected by the pulsed laser ablation (PLA) of a solid target. Mass spectra show that the PLA of Ni, Al, and ZnO targets, in vacuum, using the second harmonic of a Nd:YAG laser (532 nm, pulse duration {approx}10 ns) generates abundant X{sup n+} ions (n{<=}3 for Ni, {<=}2 for Al, {<=}3 and {<=}2 for Zn and O respectively from ZnO). Ions are selected by their mass/charge (m/z) ratio prior to the determination of their times of flight. PLA of Ni has been studied in most detail. The mean velocities of ablated Ni{sup n+} ions are shown to follow the trend v(Ni{sup 3+})>v(Ni{sup 2+})>v(Ni{sup +}). Data from Ni{sup 2+} and Ni{sup 3+} are fitted to shifted Maxwellian functions and agree well with a model which assumes both thermal and Coulombic contributions to ion velocities. The dependence of ion velocities on laser pulse energy (and fluence) is investigated, and the high energy data are shown to be consistent with an effective accelerating voltage of {approx}90 V within the plume. The distribution of velocities associated with Ni{sup 3+} indicates a population at cooler temperature than Ni{sup 2+}.

Sage, Rebecca S.; Cappel, Ute B.; Ashfold, Michael N. R.; Walker, Nicholas R. [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)

2008-05-01T23:59:59.000Z

363

Standard test method for analysis of isotopic composition of uranium in nuclear-grade fuel material by quadrupole inductively coupled plasma-mass spectrometry  

E-Print Network [OSTI]

1.1 This test method is applicable to the determination of the isotopic composition of uranium (U) in nuclear-grade fuel material. The following isotopic weight percentages are determined using a quadrupole inductively coupled plasma-mass spectrometer (Q-ICP-MS): 233U, 234U, 235U, 236U, and 238U. The analysis can be performed on various material matrices after acid dissolution and sample dilution into water or dilute nitric (HNO3) acid. These materials include: fuel product, uranium oxide, uranium oxide alloys, uranyl nitrate (UNH) crystals, and solutions. The sample preparation discussed in this test method focuses on fuel product material but may be used for uranium oxide or a uranium oxide alloy. Other preparation techniques may be used and some references are given. Purification of the uranium by anion-exchange extraction is not required for this test method, as it is required by other test methods such as radiochemistry and thermal ionization mass spectroscopy (TIMS). This test method is also described i...

American Society for Testing and Materials. Philadelphia

2000-01-01T23:59:59.000Z

364

Liquid Microjunction Surface Sampling Coupled with High-Pressure Liquid Chromatography-Electrospray Ionization-Mass Spectrometry for Analysis of Drugs and Metabolites in Whole-Body Thin Tissue Sections  

SciTech Connect (OSTI)

In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, two isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent.

Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2010-01-01T23:59:59.000Z

365

Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals  

SciTech Connect (OSTI)

In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

2009-03-01T23:59:59.000Z

366

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)

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.

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

2011-02-01T23:59:59.000Z

367

Applications of High-Resolution Electrospray Ionization Mass...  

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

High-Resolution Electrospray Ionization Mass Spectrometry to Measurements of Average Oxygen to Carbon Ratios in Applications of High-Resolution Electrospray Ionization Mass...

368

Nuclear Masses in Astrophysics  

E-Print Network [OSTI]

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

369

Licenses Available in Chemicals | Tech Transfer | ORNL  

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

Soot Synthesis of Fullerenes and Nanotubes without Carbonaceous Soot 200100968 Melt-spun Carbon Fiber Precursors Containing Lignin 200100974 Real-Time Ion Trap Mass Spectrometry...

370

Chemical Characterization of Crude Petroleum Using Nanospray...  

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

Coupled with High-Resolution Abstract: Nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was used for the first time for...

371

ablation-absorption ratio spectrometry: Topics by E-print Network  

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

isotopes 2 A gas chromatographypyrolysisisotope ratio mass spectrometry system for high-precision dD measurements Environmental Sciences and Ecology Websites Summary: of...

372

Separation and Classification of Lipids Using Differential Ion Mobility Spectrometry  

SciTech Connect (OSTI)

Correlations between the dimensions of a 2-D separation create trend lines that normally depend on structural or functional characteristics of the compound class and thus facilitate classification of unknowns. This broadly applies to conventional ion mobility spectrometry (IMS)/mass spectrometry (MS), where the major biomolecular classes (e.g., lipids, peptides, nucleotides) occupy different trend line domains. However, strong correlation between the IMS and MS separations for ions of same charge has impeded finer distinctions. Differential IMS (or FAIMS) is generally much less correlated to MS and thus should better separate the trend lines and associated domains. We report the first observation of chemical class separation by trend lines using FAIMS, here for lipids. For all lipids, FAIMS is indeed more independent of MS than conventional IMS, and subclasses (such as phospho-, glycero-, or sphingolipids) form distinct, often non-overlapping domains. Even finer categories with different functional groups or degrees of unsaturation are often separated. As expected, resolution improves in He-rich gases: at ~70% He, glycerolipid isomers with different positions of fatty acid attachment can be resolved. These results open the door for lipidomics application of FAIMS, particularly shotgun lipidomics and targeted analyses of bioactive lipids.

Shvartsburg, Alexandre A.; Isaac, Georgis; Leveque, Nathalie; Smith, Richard D.; Metz, Thomas O.

2011-04-12T23:59:59.000Z

373

Laboratory investigation of chemical and physical properties of soot-containing aerosols  

E-Print Network [OSTI]

....................................................................................44 3-6 Hygroscopic growth factor of H2SO4-coated (a) propane (b) methane and (c) kerosene soot aerosols of selected dry particle sizes as a function of RH... on the surfaces of soot generated from methane, hexane and kerosene combustion. The kinetic experiments are conducted with a low-pressure, coated-wall laminar flow reactor 8 apparatus equipped with ion drift - chemical ionization mass spectrometry...

Zhang, Dan

2006-08-16T23:59:59.000Z

374

Mass spectrometry with a very small cyclotron  

SciTech Connect (OSTI)

It is proposed that direct detection of natural radioisotopes can be accomplished by using a very low energy (20 to 100 keV) cyclotron accelerating negative ions.

Muller, R.A.; Tans, P.P.; Mast, T.S.; Welch, J.J.

1981-05-01T23:59:59.000Z

375

Mapping Molecular Space with Mass Spectrometry /  

E-Print Network [OSTI]

L & Owende P (2010) Biofuels from microalgae—A review of2009) Microalgae as a raw material for biofuels production.microalgae. Current research aims to produce traditional biofuels

Nguyen, Don Duy

2013-01-01T23:59:59.000Z

376

Signatures for Mass Spectrometry Data Quality  

SciTech Connect (OSTI)

Ensuring data quality and proper instrument functionality is a prerequisite for scientific investigation. Manual validation for quality assurance is time consuming, expensive and subjective. Metrics for describing various features of LC-MS data have been developed to assist operators in discriminating poor (out of control) and good (in control) datasets. However, the wide variety of instrument specifications and LC-MS configurations precludes applying a simple range of acceptable values or cutoffs for such metrics. We explored a variety of statistical modeling approaches to predict the quality of LC-MS data. Using 1164 manually classified quality control (QC) LC-MS datasets, we fit logistic regression classification models to the QC data to predict whether a dataset is in or out of control. Model parameters were optimized by minimizing a loss function that accounts for the tradeoff between false positive and false negative errors. The optimal logistic regression classifier models detected bad data sets with high sensitivity (i.e. low false negative rate) while maintaining high specificity (i.e. controlling the false positive rate). As an example, predictions for Velos-Orbitrap instrumentation data had a sensitivity of 93.7% in detecting out of control datasets with a false positive rate of 8.3%. In comparison, we investigated the performance of several single metrics in predicting dataset quality. While maintaining a sensitivity of 93.7%, the corresponding false positive rates for these single-metric models unacceptably ranged from 32% to 97.7%. Finally, we evaluated the performance of the

Amidan, Brett G.; Orton, Daniel J.; Lamarche, Brian L.; Monroe, Matthew E.; Moore, Ronald J.; Venzin, Alexander M.; Smith, Richard D.; Sego, Landon H.; Tardiff, Mark F.; Payne, Samuel H.

2014-03-10T23:59:59.000Z

377

Mapping Molecular Space with Mass Spectrometry /  

E-Print Network [OSTI]

microalgae. Current research aims to produce traditional biofuels from algae, but their potential to generate sustainable energy

Nguyen, Don Duy

2013-01-01T23:59:59.000Z

378

PHOTOIONIZED TOF MASS SPECTROMETRY OF ATOMIC CLUSTERS  

E-Print Network [OSTI]

for sev eral cluster sou rce nozzle condition s. Heliu m gas pressu re at the tim e of v aporization of solid m aterial played the key role in cluster size range obtain ed. Th e effect of pressu re was thorou

Maruyama, Shigeo

379

Aerosol mass spectrometry systems and methods  

DOE Patents [OSTI]

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.

Fergenson, David P.; Gard, Eric E.

2013-08-20T23:59:59.000Z

380

Mapping Molecular Space with Mass Spectrometry /  

E-Print Network [OSTI]

L & Oliveira AC (2009) Microalgae as a raw material forP (2010) Biofuels from microalgae—A review of technologiesThe tide turns towards microalgae. Current research aims to

Nguyen, Don Duy

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Improving liquid chromatography-mass spectrometry sensitivity...  

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

sensitivity using a subambient pressure ionization with nanoelectrospray (SPIN Abstract: In this work the Subambient Pressure Ionization with Nanoelectrospray (SPIN) ion...

382

Ultrasensitive Nanoelectrospray Ionization-Mass Spectrometry using  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layeredof2014 EIAUltrafast Transformations

383

Next-Generation Mass Spectrometry | EMSL  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andDataNationalNewport News Business55NewsNext Jefferson

384

CAMS Center for Accelerator Mass Spectrometry  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home| Visitors| Education|About NationalEnergyWhy the

385

Application of Electron Transfer Dissociation Mass Spectrometry...  

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

glycation of peptides and proteins by D-glucose has important implications in diabetes mellitus research, particularly in the context of development of diabetic...

386

Beyond single particle mass spectrometry: multidimensional characterisation  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6 M. Babzien, I.Program Information AboutBetterBetter Nationalof

387

Electrospray Mass Spectrometry | The Ames Laboratory  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing Zirconia Nanoparticles as SelectiveElectronic Structurefunctional

388

Signatures for Mass Spectrometry Data Quality. | EMSL  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing Smart GridShift EndSidney D.Christopher

389

In Silico Identification Software (ISIS): A Machine Learning Approach to Tandem Mass Spectral Identification of Lipids  

SciTech Connect (OSTI)

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.

Kangas, Lars J.; Metz, Thomas O.; Isaac, Georgis; Schrom, Brian T.; Ginovska-Pangovska, Bojana; Wang, Luning; Tan, Li; Lewis, Robert R.; Miller, John H.

2012-05-15T23:59:59.000Z

390

Decommissioning samples from the Ft. Lewis, WA, solvent refined coal pilot plant: chemical analysis and biological testing  

SciTech Connect (OSTI)

This report presents the results from chemical analyses and limited biological assays of three sets of samples from the Ft. Lewis, WA solvent refined coal (SRC) pilot plant. The samples were collected during the process of decommissioning this facility. Chemical composition was determined for chemical class fractions of the samples by using high-resolution gas chromatography (GC), high-resolution GC/mass spectrometry (MS) and high-resolution MS. Biological activity was measuring using both the histidine reversion microbial mutagenicity assay with Salmonella typhimurium, TA98 and an initiation/promotion mouse-skin tumorigenicity assay. 19 refs., 7 figs., 27 tabs.

Weimer, W.C.; Wright, C.W.

1985-10-01T23:59:59.000Z

391

High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray...  

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

in Situ Imaging by Nanospray Desorption Electrospray Ionization Mass Spectrometry. High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray Desorption Electrospray...

392

Electrospray ionization mass spectrometric characterization of acrylamide adducts to hemoglobin  

SciTech Connect (OSTI)

The most common procedure to identify hemoglobin adducts has been to cleave the adducts from the protein and characterize the adducting species, by, for example, derivatization and gas chromatography/mass spectrometry. To extend these approaches we used electrospray ionization mass spectrometry (ESI-MS) to characterize adducted hemoglobin. For this we incubated [[sup 14]C]acrylamide with the purified human hemoglobin (type A[sub 0]) under conditions that yielded high adduct levels. When the hemoglobin was separated by reversed-phase high-performance liquid chromatography (HPLC), 65% of the radioactivity copurified with the [beta]-subunit. Three adducted species were prominent in the ESI mass spectrum of the intact [beta]-subunit, indicating acrylamide adduction (i.e., mass increase of 71 Da) and two addition unidentified moieties with mass increments of 102 and 135 Da. Endoproteinase Glu-C digestion of the adducted [beta]-subunit resulted in a peptide mixture that, upon reversed-phase HPLC separation, provided several radiolabeled peptides. Using ESI-MS we identified these as the V[sub 91-101] and V[sub 102-122] peptides that represent the cysteine-containing peptides of the [beta]-subunit. These results provide definitive information on acrylamide-modified human hemoglobin and demonstrate that ESI-MS provides valuable structure information on chemically adducted proteins. 30 refs., 9 figs., 3 tabs.

Springer, D.L.; Goheen, S.C.; Edmonds, C.G. (Pacific Northwest Lab., Richland, WA (United States)); Bull, R.J.; Sylvester, D.M. (Washington State Univ., Pullman, WA (United States))

1993-01-01T23:59:59.000Z

393

International Journal of Mass Spectrometry 260 (2007) 222–236 Extended data analysis strategies for high resolution imaging MS: New methods to deal with extremely large image hyperspectral datasets  

E-Print Network [OSTI]

The large size of the hyperspectral datasets that are produced with modern mass spectrometric imaging techniques makes it difficult to analyze the results. Unsupervised statistical techniques are needed to extract relevant information from these datasets and reduce the data into a surveyable overview. Multivariate statistics are commonly used for this purpose. Computational power and computer memory limit the resolution at which the datasets can be analyzed with these techniques. We introduce the use of a data format capable of efficiently storing sparse datasets for multivariate analysis. This format is more memory-efficient and therefore it increases the possible resolution together with a decrease of computation time. Three multivariate techniques are compared for both sparse-type data and non-sparse data acquired in two different imaging ToF-SIMS experiments and one LDI-ToF imaging experiment. There is no significant qualitative difference in the use of different data formats for the same multivariate algorithms. All evaluated multivariate techniques could be applied on both SIMS and the LDI imaging datasets. Principal component analysis is shown to be the fastest choice; however a small increase of computation time using a VARIMAX optimization increases the decomposition quality significantly. PARAFAC analysis is shown to be very effective in separating different chemical components but the calculations take a significant amount of time, limiting its use as a routine technique. An effective visualization of the results of the multivariate analysis is as important for the analyst as the computational issues. For this reason, a new technique for visualization is presented, combining both spectral loadings and spatial

Leendert A. Klerk A; Er Broersen B; Ian W. Fletcher C

2006-01-01T23:59:59.000Z

394

Vitrification and testing of a Hanford high-level waste sample. Part 1: Glass fabrication, and chemical and radiochemical analysis  

SciTech Connect (OSTI)

The Hanford radioactive tank waste will be separated into low-activity waste and high-level waste that will both be vitrified into borosilicate glasses. To demonstrate the feasibility of vitrification and the durability of the high-level waste glass, a high-level waste sample from Tank AZ-101 was processed to glass in a hot cell and analyzed with respect to chemical composition, radionuclide content, waste loading, and the presence of crystalline phases and then tested for leachability. The glass was analyzed with inductively coupled plasma-atomic emission spectroscopy, inductively coupled plasma-mass spectrometry, ? energy spectrometry, ? spectrometry, and liquid scintillation counting. The WISE Uranium Project calculator was used to calculate the main sources of radioactivity to the year 3115. The observed crystallinity and the results of leachability testing of the glass will be reported in Part 2 of this paper.

Hrma, Pavel R.; Crum, Jarrod V.; Bates, Derrick J.; Bredt, Paul; Greenwood, Lawrence R.; Smith, H D.

2005-10-01T23:59:59.000Z

395

2, 21672208, 2002 Chemical mass  

E-Print Network [OSTI]

results simulating water soluble organic compound production by gas-to-particle conversion an important role in the atmosphere for several reasons. They transport material through the atmosphere, affect

Boyer, Edmond

396

Investigation of high temperature gaseous species by Knudsen cell mass spectrometry above the condensed systems Cu-Y-Ru-C, Ag-Y-Ru-C, and Au-Y- Ru-C  

E-Print Network [OSTI]

of the total ion intensities listed in Tables 2 through 5, + + except those for RuC and YC2, were calculated by dividing the individual isotopic species by the isotopic abundance of that species according to Equation 1, where I is the total intensity of all... not be used because their mass to charge ratios overlap. For these iona, an + algebraic equation was used which compared the ratios of YC (Mass 113), YC2 (Mass 114), RuC (Mass 113), and RuC (Mass 114). The + + + calculated isotopic abundances...

Wilhite, Dale Wayne

1988-01-01T23:59:59.000Z

397

CHEMICAL SENSORS School of Chemistry and Biochemistry  

E-Print Network [OSTI]

CHEMICAL SENSORS CHEM 6282 School of Chemistry and Biochemistry Chemical sensors physics and electronics or a chemical instrumentation course. The topics covered will include general theory of chemical recognition, electrochemical, optical, mass sensors and data reduction. Text: J

Sherrill, David

398

12.141 Electron Microprobe Analysis by Wavelength Dispersive X-ray Spectrometry, January IAP 2010  

E-Print Network [OSTI]

This lab-oriented course introduces the student to the subject of X-ray spectrometry and micro-scale chemical quantitative analysis of solid samples through an intensive series of hands-on laboratory exercises that use the ...

Chatterjee, Nilanjan

2010-01-01T23:59:59.000Z

399

0 Copyright 1994 by the American Chemical Society Accelerated Publications  

E-Print Network [OSTI]

and its covalent linkage to the protein. Elemental composition data from high-resolution mass spectrometry; MS, mass spectrometry; UV, ultraviolet; LC, liquid chromatography; HPLC, high-performance LC; FAB to capture and use energy from a photon of light depends on the chromophore, its linkage to the protein

Borgstahl, Gloria

400

Chemical compounds and toxicological assessments of drinking water stored in polyethylene terephthalate (PET)  

E-Print Network [OSTI]

Chemical compounds and toxicological assessments of drinking water stored in polyethyleneMS, gas chromatographyemass spectrometry; HDPE, high density polyethylene; HULYs, human blood lymphocytes

Short, Daniel

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

JOURNAL DE PHYSIQUE Colloque C 2, supplkment au no 3-4, Tome 28, mars-avril1967, page C 2 -87 RAPID SCANNING FOURIER TRANSFORM SPECTROMETRY  

E-Print Network [OSTI]

scanning serves to mitigate the problems of scintillation and dynamic range for Fourier spectrometry. Scintillation noise due to atmospheric turbulence can easily relegate astronomical spectrometry to the last RAPID SCANNING FOURIER TRANSFORM SPECTROMETRY Block Associates, Inc., Cambridge, Mass., U. S. A. Rksumk

Paris-Sud XI, Université de

402

Standard practices for dissolving glass containing radioactive and mixed waste for chemical and radiochemical analysis  

E-Print Network [OSTI]

1.1 These practices cover techniques suitable for dissolving glass samples that may contain nuclear wastes. These techniques used together or independently will produce solutions that can be analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), radiochemical methods and wet chemical techniques for major components, minor components and radionuclides. 1.2 One of the fusion practices and the microwave practice can be used in hot cells and shielded hoods after modification to meet local operational requirements. 1.3 The user of these practices must follow radiation protection guidelines in place for their specific laboratories. 1.4 Additional information relating to safety is included in the text. 1.5 The dissolution techniques described in these practices can be used for quality control of the feed materials and the product of plants vitrifying nuclear waste materials in glass. 1.6 These pr...

American Society for Testing and Materials. Philadelphia

2000-01-01T23:59:59.000Z

403

Journal of Chemical Ecology, Vol.23, No. 4, 1997 CUTICULAR HYDROCARBONS OF TERMITES OF THE  

E-Print Network [OSTI]

--Cuticularhydrocarbons, chemotaxonomy, Isoptera, tropical ter- mites, gas chromatography, mass spectrometry, Virgin Islands, Caribbean scintillation vials over a single 75-W, reflecting incandescent light.

Yorke, James

404

Service Level Agreement for the Analytical Laboratory School of Biological and Chemical Sciences  

E-Print Network [OSTI]

.g.scott@qmul.ac.uk Definition of Service The Analytical Laboratory offers facilities for Atomic Absorption Spectrometry, Chromatography, Mass Spectrometry and Radioisotope Measurement. Users of the service are encouraged to actively Provided · The Atomic Absorption Spectrometry facility is able to provide quantitative analysis of a wide

Chittka, Lars

405

Spectral networks algorithms for de novo interpretation of tandem mass spectra  

E-Print Network [OSTI]

high-energy collision-induced dissociation spectra of singly protonated peptides by ’SeqMS’, a software aid for de novo sequencing by tandem mass spectrometry.

Bandeira, Nuno Filipe Cabrita

2007-01-01T23:59:59.000Z

406

andliquid chromatography-tandem mass: Topics by E-print Network  

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

using isotope dilution high performance liquid chromatography-tandem mass spectrometry. Open Access Theses and Dissertations Summary: ??A method has been developed for...

407

aerosol time-of-flight mass: Topics by E-print Network  

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

Theses and Dissertations Summary: ??The construction of a liquid nitrogen-cooled ion mobility spectrometer coupled with time-of-flight mass spectrometry was implemented to...

408

Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 2: Analysis of the Biomass Burning Contribution and the Modern Carbon Fraction  

SciTech Connect (OSTI)

Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS) and complementary instrumentation. Positive Matrix Factorization (PMF) of high resolution AMS spectra identified a biomass burning OA (BBOA) component, which includes several large plumes that appear to be from forest fires within the region. Here, we show that the AMS BBOA concentration at T0 correlates with fire counts in the vicinity of Mexico City and that most of the BBOA variability is captured when the FLEXPART model is used for the dispersion of fire emissions as estimated from satellite fire counts. The resulting FLEXPART fire impact index correlates well with the observed BBOA, CH3CN, levoglucosan, and potassium, indicating that wildfires in the region surrounding Mexico City are the dominant source of BBOA at T0 during MILAGRO. The impact of distant BB sources such as the Yucatan is very small during this period. All fire tracers are correlated, with BBOA and levoglucosan showing little background, acetonitrile having a well-known tropospheric background of ~100-150 ppt, and PM2.5 potassium having a background of ~160 ng m-3 (two-thirds of its average concentration), which does not appear to be related to BB sources.

Aiken, Allison; de Foy, B.; Wiedinmyer, Christine; DeCarlo, Peter; Ulbrich, Ingrid M.; Wehrli, M. N.; Szidat, S.; Prevot, A. S. H.; Noda, J.; Wacker, L.; Volkamer, Rainer M.; Fortner, Edward; Wang, J. X.; Laskin, Alexander; Shutthanandan, V.; Zheng, J.; Zhang, Renyi; Paredes-Miranda, Guadalupe L.; Arnott, W. P.; Molina, Luis; Sosa, G.; Querol, X.; Jimenez, J. L.

2010-06-16T23:59:59.000Z

409

Anal. Chem. 1981, 53, 1241-1244 1241 Comparison of Mass Spectra Obtained with Low-Energy Ion  

E-Print Network [OSTI]

and High-Energy Californium-252 Fission Fragment Bombardment Werner Ens and K. G. Standing Physics mass spectrometry (1,2)and low-energy ion bombardment mass spectrometry (3-5). In these techniquesAnal. Chem. 1981, 53, 1241-1244 1241 Comparison of Mass Spectra Obtained with Low-Energy Ion

Chait, Brian T.

410

Separation and Quantification of Chemically Diverse Analytes in Neutron Irradiated Fissile Materials  

SciTech Connect (OSTI)

Quantitative measurement of fission and activation products resulting from neutron irradiation of fissile materials is of interest for applications in environmental monitoring, nuclear waste management, and national security. To overcome mass and spectral interferences, and the relative small quantities of some target analytes, an extensive series of chemical separations is necessary. Based on established separations processes involving co-precipitation, solvent extraction, and ion-exchange and extraction chromatography, we have been evaluating and optimizing a proposed sequence of separation steps to allow for the timely quantification of analytes of interest. For simplicity, much of the chemical separation development work has been performed using stable elements as surrogates for the radioactive material. We have recently evaluated the optimized procedures using an irradiated sample to examine the adequacy of separations for measurement of desired analytes by gamma spectrometry. Here we present the results of this evaluation and describe the radiochemical separations utilized.

Douglas, Matthew; Friese, Judah I.; Greenwood, Lawrence R.; Farmer, Orville T.; Thomas, Linda MP; Maiti, Tapas C.; Finn, Erin C.; Garofoli, Stephanie J.; Gassman, Paul L.; Huff, Morgan M.; Schulte, Shannon M.; Smith, Steven C.; Thomas, Kathie K.; Bachelor, Paula P.

2009-10-01T23:59:59.000Z

411

Formation of iron complexs from trifluoroacetic acid based liquid chromatography mobile phases as interference ions in liquid chromatography/electrospray ionization mass spectrometric analysis  

SciTech Connect (OSTI)

Two unexpected singly charged ions at m/z 1103 and 944 have been observed in mass spectra obtained from electrospray ionization-mass spectrometric analysis of liquid chromatography effluents with mobile phases containing trifluoroacetic acid. Accurate mass measurement and tandem mass spectrometry studies revealed that these two ions are not due to any contamination from solvents and chemicals used for mobile and stationary phases or from the laboratory atmospheric environment. Instead these ions are clusters of trifluoroacetic acid formed in association with acetonitrile, water and iron from the stainless steel union used to connect the column with the electrospray tip and to apply high voltage; the molecular formulae are Fe+((OH)(H2O)2)9(CF3COOH)5 and Fe+((OH)(H2O)2)6 (CF3COOH)5.

Shukla, Anil K.; Zhang, Rui; Orton, Daniel J.; Zhao, Rui; Clauss, Therese RW; Moore, Ronald J.; Smith, Richard D.

2011-05-30T23:59:59.000Z

412

Algorithms for tandem mass spectrometry-based proteomics  

E-Print Network [OSTI]

An introduction to the conjugate gradient method without theusing a nonlinear Conjugate Gradient method [196]. LogisticA nonlinear Conjugate Gradient method [196] was used to

Frank, Ari Michael

2008-01-01T23:59:59.000Z

413

Mass Spectrometry and Density Functional Theory Characterizations of DNA Modifications  

E-Print Network [OSTI]

alkaline phosphatase (CIP). We chose Incorporation of DNADigestion NP1, exoPII, CIP, exoPI + Internal Standard Enzymethe addition of exoPI and CIP. Similar to NPI, exoPI creates

Williams, Renee Therese

2012-01-01T23:59:59.000Z

414

Plasma desorption mass spectrometry of organics at low temperatures  

E-Print Network [OSTI]

The desorption/ionization of volatile hydrocarbons by Plasma Desorption (PD) produces a series of molecular ions. Among these are deprotonated molecular ions, which are not usually observed in PD. The H-loss phenomenon was examined as a function...

Shirey, Eldon Lynn

1993-01-01T23:59:59.000Z

415

Extending the Capabilities of Single Particle Mass Spectrometry...  

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

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...

416

Quantitative analysis of amino acid mixtures by mass spectrometry  

E-Print Network [OSTI]

C~hto Gibert& and J. Oro, 'l, 604 (1969). 16. S. D. Cliristian, 0. Chem. Educ. , 42, 604 (1965) 17. L. G. Sillcri, Acta Chem. Scancl. , I8, 1085 (1964) 18. R. D. Gr i@shy, C. O. Ilaiisen, D. G. I"lai, ne. in9, G. Eox, and R. II. Cole, Ar al...

Bird, James Spencer

1971-01-01T23:59:59.000Z

417

Algorithms for tandem mass spectrometry-based proteomics  

E-Print Network [OSTI]

By restricting this advanced search to the set of unidenti?require time-consuming advanced search techniques. Insteadimplementation of the advanced database searches such as the

Frank, Ari Michael

2008-01-01T23:59:59.000Z

418

Deuterium exchange mass spectrometry studies of the phospholipase A? superfamily  

E-Print Network [OSTI]

of inhibitor bound GIVA PLA 2 using molecular modeling andDXMS Studies of Group IA PLA 2 Utilizing Novel Methods forIA phospholipase A 2 (GIA PLA 2 ) was carried out in the

Burke, John Edmund

2008-01-01T23:59:59.000Z

419

Mass spectrometry-based discovery of circadian peptides  

E-Print Network [OSTI]

with space and time. Two solid-phase extraction collection strategies are presented that relate time in the brain. little SAAS neuropeptides solid-phase extraction peptidomics suprachiasmatic nucleus neuropeptide- based transmitters and modulators within dynamic neural net- works. Neuropeptides include a broad

Gillette, Martha U.

420

Isoelectric Trapping and Mass Spectrometry: Tools for Proteomics  

E-Print Network [OSTI]

extremely complex mixtures leading to the coupling of different chromatographic and/or electrophoretic techniques.14 MULTI-DIMENSIONAL PROTEIN IDENTIFICATION TEHCHNOLOGY One of the most utilized techniques for bottom-up proteomic studies... researchers prefer an experimental platform that utilizes 1D or 2D-GE followed by excision of each protein band (or entire gel lanes) and tryptic digestion.25 The resulting peptides are then subjected to MS analysis or are separated using LC (GeLC) prior...

Cologna, Stephanie Marie

2012-02-14T23:59:59.000Z

Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Applications of Ionic Clusters in High Resolution Mass Spectrometry  

E-Print Network [OSTI]

with the solvation energies of the reactant E solv (3+)and product E solv (2+) clusters (eq 2 and 3) obtained from6 (H 2 O) n 3+(g) #G = –E solv (3+) Ru(NH 3 ) 6 (H 2 O) n 2

Leib, Ryan David

2010-01-01T23:59:59.000Z

422

Targeted Tandem Mass Spectrometry for High-Throughput Comparative  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystallineForeign ObjectOUR8, 2013 FINAL MEETINGEnergy

423

New Mass Spectrometry Techniques for Studying Physical Chemistry of  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andDataNational Library of1,Department ofNewofLaser'sLocalNew

424

Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2) Sr (2)ScienceScientistsON THE ANALYSIS O Fcompleted;

425

Absorption Mode FT-ICR Mass Spectrometry Imaging. | EMSL  

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426

21 Tesla mass spectrometry magnet arrives at EMSL | EMSL  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience hands-onASTROPHYSICS H.CarbonMarch Value of the verb5Np,331.0 -21

427

Investigation of Metalloproteins Utilizing High Resolution Mass Spectrometry  

E-Print Network [OSTI]

.............................................................. 79 30 Fragment ion spectra of the [M+H]+ ions (a) Ac- Y(AEAAKA)2F-NH2 (-OCH3), (b) Ac-Y(AEAAKA)2F-NH2 (- 2OCH3) and (c) Ac-Y(AEAAKA)2F-NH2 (-3CH3)................. 82 31 Arrival time distribution (ATD) of the [M+H]+ ions of (a) Ac- Y...(AEAAKA)2F-NH2 (3OCH3) (FWHM:14), (b) Ac- Y(AEAAKA)2F-NH2 (2OCH3) (FWHM:25), (c) Ac- Y(AEAAKA)2F-NH2 (OCH3) (FWHM:21) and (d) Ac- Y(AEAAKA)2F-NH2 (FWHM:31)......................................... 85 32 Arrival time distribution (ATD) of the [M...

Wu, Zhaoxiang

2011-08-08T23:59:59.000Z

428

Monitoring Trace Radionuclides by ICP Mass Spectrometry with Femtosecond  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment SurfacesResource ProgramModification andinterface of water.OrganicNov 4 5 6Laser

429

Multiplexed Ion Mobility Spectrometry - Orthogonal Time-Of-Flight Mass  

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

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430

The future of liquid chromatography-mass spectrometry in metabolic  

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

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431

High-Resolution Desorption Electrospray Ionization Mass Spectrometry for  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinement plasmas in thein theSurfactant-Assisted Fabrication.

432

High-Resolution Electrospray Ionization Mass Spectrometry Analysis of  

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

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433

Extending the Capabilities of Single Particle Mass Spectrometry: I.  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicy andExsolution Enhanced Oil Recovery with Concurrent CO2students

434

Extending the Capabilities of Single Particle Mass Spectrometry: II.  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicy andExsolution Enhanced Oil Recovery with Concurrent

435

Giga-Dalton Mass Spectrometry - Energy Innovation Portal  

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

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436

21 Tesla mass spectrometry magnet arrives at EMSL | EMSL  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011 Mon, Next2025 Power Marketing Initiative1 Tesla

437

Improvements in Inductively Coupled Plasma - Mass Spectrometry | The Ames  

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438

Improving liquid chromatography-mass spectrometry sensitivity using a  

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

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439

Automated Surface Sampling Probe for Mass Spectrometry - Energy Innovation  

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

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440

Liquid Chromatography Mass Spectrometry-Based Proteomics: Biological and  

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

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Note: This page contains sample records for the topic "mass spectrometry chemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Liquid Chromatography-Mass Spectrometry-based Quantitative Proteomics. |  

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

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442

Mass spectrometry in biomarker applications: from untargeted discovery to  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces andMapping the Nanoscale Landscape PrintSurveyMary

443

Mass spectrometry on bio-renewable fuels | The Ames Laboratory  

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

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444

Mass spectrometry-based proteomics: existing capabilities and future  

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

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445

Anasys licenses ORNL nanoscale mass spectrometry imaging technology |  

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

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446

Applications of High-Resolution Electrospray Ionization Mass Spectrometry  

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447

Mass Spectrometer: Ion Mobility Spectrometry, Time of Flight | EMSL  

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448

Single Cell Analysis Using Microfluidics Coupled to Ultrasensitive Mass Spectrometry  

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

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449

Application of Electron Transfer Dissociation Mass Spectrometry in Analyses  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone by E-mailRadioimmunotherapy of Cancers.Appendix 2015of

450

Applications of High-Resolution Electrospray Ionization Mass Spectrometry  

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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone by E-mailRadioimmunotherapy ofevolved gas

451

Atmospheric Solids Analysis Probe Mass Spectrometry: A New Approach for  

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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone byDear Friend,Arthur J. Nozik -GrownAnAtmosphericAirborne

452

Recovering Sparse Low-rank Blocks in Tandem Mass Spectrometry  

E-Print Network [OSTI]

, Pedro Navarro2, and Richard G. Baraniuk1 1 Rice University, Houston, TX, USA; e-mail: {studer, richb}@rice.edu 2 ETH Z¨urich, Z¨urich, Switzerland; e-mail: graemepope@gmail.com, navarro

453

Anasys licenses ORNL nanoscale mass spectrometry imaging technology...  

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

in imaging resolution as small as 250 nanometers, or 1400th the thickness of a human hair. "This capability could have a tremendous impact on a broad field of applications in...

454

Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants  

SciTech Connect (OSTI)

Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energy’s (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids producing a small plume containing uranium atoms. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement has high relative precision and detection limits approaching the femtogram range for uranium. It is independent of chemical form and degree of dilution with nuisance dust and other materials. High speed sample scanning and pinpoint characterization allow measurements on millions of particles/hour to detect and analyze the enrichment of trace uranium in samples. The spectrometer is assembled using commercially available components at comparatively low cost, and features a compact and low power design. Future designs can be engineered for reliable, autonomous deployment within an industrial plant environment. Two specific applications of the spectrometer are under development: 1) automated unattended aerosol sampling and analysis and 2) on-site small sample destructive assay measurement. The two applications propose game-changing technological advances in gaseous centrifuge enrichment plant (GCEP) safeguards verification. The aerosol measurement instrument, LAARS-environmental sampling (ES), collects aerosol particles from the plant environment in a purpose-built rotating drum impactor and then uses LAARS-ES to quickly scan the surface of the impactor to measure the enrichments of the captured particles. The current approach to plant misuse detection involves swipe sampling and offsite analysis. Though this approach is very robust it generally requires several months to obtain results from a given sample collection. The destructive assay instrument, LAARS-destructive assay (DA), uses a simple purpose-built fixture with a sampling planchet to collect adsorbed UF6 gas from a cylinder valve or from a process line tap or pigtail. A portable LAARS-DA instrument scans the microgram quantity of uranium collected on the planchet and the assay of the uranium is measured to ~0.15% relative precision. Currently, destructive assay samples for bias defect measurements are collected in small sample cylinders for offsite mass spectrometry measurement.

Anheier, Norman C.; Cannon, Bret D.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

2012-07-01T23:59:59.000Z

455

Fragranced consumer products: Chemicals emitted, ingredients unlisted  

SciTech Connect (OSTI)

Fragranced consumer products are pervasive in society. Relatively little is known about the composition of these products, due to lack of prior study, complexity of formulations, and limitations and protections on ingredient disclosure in the U.S. We investigated volatile organic compounds (VOCs) emitted from 25 common fragranced consumer products-laundry products, personal care products, cleaning supplies, and air fresheners-using headspace analysis with gas chromatography/mass spectrometry (GC/MS). Our analysis found 133 different VOCs emitted from the 25 products, with an average of 17 VOCs per product. Of these 133 VOCs, 24 are classified as toxic or hazardous under U.S. federal laws, and each product emitted at least one of these compounds. For 'green' products, emissions of these compounds were not significantly different from the other products. Of all VOCs identified across the products, only 1 was listed on any product label, and only 2 were listed on any material safety data sheet (MSDS). While virtually none of the chemicals identified were listed, this nonetheless accords with U.S. regulations, which do not require disclosure of all ingredients in a consumer product, or of any ingredients in a mixture called 'fragrance.' Because the analysis focused on compounds emitted and listed, rather than exposures and effects, it makes no claims regarding possible risks from product use. Results of this study contribute to understanding emissions from common products, and their links with labeling and legislation.

Steinemann, Anne C., E-mail: acstein@u.washington.ed [University of Washington, Department of Civil and Environmental Engineering, and Evans School of Public Affairs, Seattle, WA 98195-2700 (United States); MacGregor, Ian C.; Gordon, Sydney M. [Battelle Memorial Institute (United States); Gallagher, Lisa G.; Davis, Amy L.; Ribeiro, Daniel S. [University of Washington (United States); Wallace, Lance A. [U.S. Environmental Protection Agency (ret.) (United States)

2011-04-15T23:59:59.000Z

456

Accelerator Mass Spectrometric (AMS) Measurements of Plutonium Activity Concentrations and 240Pu/239Pu Atom Ratios In Soil Extracts Supplied by the Carlsbad Environmental Monitoring & Research Center  

SciTech Connect (OSTI)

Plutonium-239 ({sup 239}Pu) and plutonium-239+240 ({sup 239+240}Pu) activities concentrations and {sup 240}Pu/{sup 239}Pu atom ratios are reported for a series of chemically purified soil extracts received from the Carlsbad Environmental Monitoring & Research Center (CEMRC) in New Mexico. Samples were analyzed without further purification at the Lawrence Livermore National Laboratory (LLNL) using accelerator mass spectrometry (AMS). This report also includes a brief description of the AMS system and internal laboratory procedures used to ensure the quality and reliability of the measurement data.

Hamilton, T F; Brown, T A; Marchetti, A A; Martinelli, R E; Kehl, S R

2005-02-28T23:59:59.000Z

457

Subscriber access provided by Caltech Library Services Analytical Chemistry is published by the American Chemical Society. 1155  

E-Print Network [OSTI]

in Compound-Specific D/H Analysis by Gas Chromatography/Pyrolysis/Isotope-Ratio Mass Spectrometry Ying Wang in Compound-Specific D/H Analysis by Gas Chromatography/Pyrolysis/Isotope-Ratio Mass Spectrometry Ying Wang/H ratios often encounter ranges of 300 or more, and experiments using D-enriched water to study

Sessions, Alex L.

458

Molecular Characterization of Biomass Burning Aerosols Using...  

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Biomass Burning Aerosols Using High Resolution Mass Spectrometry. Molecular Characterization of Biomass Burning Aerosols Using High Resolution Mass Spectrometry. Abstract: Chemical...

459

The Application of High-Resolution Gamma-Ray Spectrometry (HRGS) to Nuclear Safeguards, Nonproliferation, and Arms Control Activities  

SciTech Connect (OSTI)

While well-developed methodologies exist for the employment of high- resolution gamma ray spectrometry (HRGS) in determining the isotopic composition of plutonium samples, the potential capabilities of such measurements in determining the properties of nuclear materials otherwise remain largely unexploited. These measurements contain information sufficiently detailed such that not only can the isotopic composition of uranium and plutonium materials be determined, but the details of the spectrum obtained will depend reproducibly upon other factors including the total mass, density, chemical composition, and geometrical configuration of the material, and for certain materials, the elapsed time since chemical processing. The potential thus exists to obtain a `gamma-ray fingerprint` for typical containers or assemblies of nuclear material which will then serve to identify that class of item in a later confirmatory measurement. These measurements have the additional advantage that, by comparison with active interrogation techniques which usually require the introduction of some extraneous form of radiation or other intrusive activity, they are totally passive, and thus impose only minimal additional safety or regulatory burdens on the operators. In the application of these measurements to the verification of treaty-limited items, where the information acquired may be sensitive in nature, the use of the CIVET (Controlled Intrusiveness Verification Technique) approach, where a computer-based interface is employed to limit access to the information obtained, may be followed.

Kane, Walter R.; Lemley, James R.; Forman, Leon

1997-12-31T23:59:59.000Z

460

7, 64136457, 2007 Single particle mass  

E-Print Network [OSTI]

to use Mexico City as a case study of air pollution mitigation while major advances continue to improve the regional air quality.5 To help decrease particulate matter (PM) pollution in Mexico City, ACPD 7, 6413­6457, 2007 Single particle mass spectrometry of Mexico City aerosols R. C. Moffet

Paris-Sud XI, Université de