skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy

Abstract

A cavity ring-down spectroscopy (CRDS) instrument was developed using mature, robust hardware for the measurement of carbon-14 in biological studies. The system was characterized using carbon-14 elevated glucose samples and returned a linear response up to 387 times contemporary carbon-14 concentrations. Carbon-14 free and contemporary carbon-14 samples with varying carbon-13 concentrations were used to assess the method detection limit of approximately one-third contemporary carbon-14 levels. Sources of inaccuracies are presented and discussed, and the capability to measure carbon-14 in biological samples is demonstrated by comparing pharmacokinetics from carbon-14 dosed guinea pigs analyzed by both CRDS and accelerator mass spectrometry. Here, the CRDS approach presented affords easy access to powerful carbon-14 tracer techniques that can characterize complex biochemical systems.

Authors:
 [1];  [1];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1367975
Report Number(s):
LLNL-JRNL-693042
Journal ID: ISSN 0003-2700
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Analytical Chemistry
Additional Journal Information:
Journal Volume: 88; Journal Issue: 17; Journal ID: ISSN 0003-2700
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 07 ISOTOPES AND RADIATION SOURCES

Citation Formats

McCartt, A. Daniel, Ognibene, Ted J., Bench, Graham, and Turteltaub, Kenneth W. Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy. United States: N. p., 2016. Web. doi:10.1021/acs.analchem.6b02054.
McCartt, A. Daniel, Ognibene, Ted J., Bench, Graham, & Turteltaub, Kenneth W. Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy. United States. doi:10.1021/acs.analchem.6b02054.
McCartt, A. Daniel, Ognibene, Ted J., Bench, Graham, and Turteltaub, Kenneth W. 2016. "Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy". United States. doi:10.1021/acs.analchem.6b02054. https://www.osti.gov/servlets/purl/1367975.
@article{osti_1367975,
title = {Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy},
author = {McCartt, A. Daniel and Ognibene, Ted J. and Bench, Graham and Turteltaub, Kenneth W.},
abstractNote = {A cavity ring-down spectroscopy (CRDS) instrument was developed using mature, robust hardware for the measurement of carbon-14 in biological studies. The system was characterized using carbon-14 elevated glucose samples and returned a linear response up to 387 times contemporary carbon-14 concentrations. Carbon-14 free and contemporary carbon-14 samples with varying carbon-13 concentrations were used to assess the method detection limit of approximately one-third contemporary carbon-14 levels. Sources of inaccuracies are presented and discussed, and the capability to measure carbon-14 in biological samples is demonstrated by comparing pharmacokinetics from carbon-14 dosed guinea pigs analyzed by both CRDS and accelerator mass spectrometry. Here, the CRDS approach presented affords easy access to powerful carbon-14 tracer techniques that can characterize complex biochemical systems.},
doi = {10.1021/acs.analchem.6b02054},
journal = {Analytical Chemistry},
number = 17,
volume = 88,
place = {United States},
year = 2016,
month = 7
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

Save / Share:
  • Accelerator Mass Spectrometry (AMS) is the most sensitive method for quantitation of 14C in biological samples. This technology has been used in a variety of low dose, human health related studies over the last 20 years when very high sensitivity was needed. AMS helped pioneer these scientific methods, but its expensive facilities and requirements for highly trained technical staff have limited their proliferation. Quantification of 14C by cavity ring-down spectroscopy (CRDS) offers an approach that eliminates many of the shortcomings of an accelerator-based system and would supplement the use of AMS in biomedical research. Our initial prototype, using a non-idealmore » wavelength laser and under suboptimal experimental conditions, has a 3.5-modern, 1-σ precision for detection of milligram-sized, carbon-14-elevated samples. Furthermore, these results demonstrate proof of principle and provided a starting point for the development of a spectrometer capable of biologically relevant sensitivities.« less
  • We have made a prototype based on CRDS with 2 {mu}m diode laser for carbon isotope analysis of CO{sub 2} in air. The carbon isotope ratio was obtained to be (1.085{+-}0.012)x10{sup -2} which shows good agreement with the isotope ratio measured by the magnetic sector-type mass spectrometer within uncertainty. Hence, we demonstrated the carbon isotope analysis based on CRDS with 2 {mu}m tunable diode laser.
  • By using an acousto-optic modulator, we have stabilized a free-running continuous wave (CW) laser diode in the presence of strong reflections from a high finesse Fabry{endash}Perot resonator. The laser diode linewidth can be stabilized from several MHz, for high resolution spectroscopy of species at low pressures, to several hundred MHz, for lower resolution spectroscopy of species at atmospheric pressures. We demonstrated CW cavity ring-down spectroscopy of water vapor at both 1 atm and 5 Torr. We achieved ring-down repetition rates of 10{endash}50 kHz, and a noise level of 2{times}10{sup {minus}8} cm{sup {minus}1}. {copyright} {ital 1997 American Institute of Physics.}
  • By using cavity ring-down absorption spectroscopy technique, we have observed the channel of Br{sub 2} molecular elimination following photodissociation of CF{sub 2}Br{sub 2} at 248 nm. A tunable laser beam, which is crossed perpendicular to the photolyzing laser beam in a ring-down cell, is used to probe the Br{sub 2} fragment in the B {sup 3}{pi}{sub ou}{sup +}-X {sup 1}{sigma}{sub g}{sup +} transition. The vibrational population is obtained in a nascent state, despite ring-down time as long as 500-1000 ns. The population ratio of Br{sub 2}(v=1)/Br{sub 2}(v=0) is determined to be 0.4{+-}0.2, slightly larger than the value of 0.22 evaluatedmore » by Boltzmann distribution at room temperature. The quantum yield of the Br{sub 2} elimination reaction is also measured to be 0.04{+-}0.01. This work provides direct evidence to support molecular elimination occurring in the CF{sub 2}Br{sub 2} photodissociation and proposes a plausible pathway with the aid of ab initio potential-energy calculations. CF{sub 2}Br{sub 2} is excited probably to the {sup 1}B{sub 1} and {sup 3}B{sub 2} states at 248 nm. As the C-Br bond is elongated upon excitation, the coupling of the {sup 1}A{sup '}({sup 1}B{sub 1}) state to the high vibrational levels of the ground state X-tilde {sup 1}A{sup '}({sup 1}A{sub 1}) may be enhanced to facilitate the process of internal conversion. After transition, the highly vibrationally excited CF{sub 2}Br{sub 2} feasibly surpasses a transition barrier prior to decomposition. According to the ab initio calculations, the transition state structure tends to correlate with the intermediate state CF{sub 2}Br+Br(CF{sub 2}Br{center_dot}{center_dot}{center_dot}Br) and the products CF{sub 2}+Br{sub 2}. A sequential photodissociation pathway is thus favored. That is, a single C-Br bond breaks, and then the free-Br atom moves to form a Br-Br bond, followed by the Br{sub 2} elimination. The formed Br-Br bond distance in the transition state tends to approach equilibrium such that the Br{sub 2} fragment may be populated in cold vibrational distribution. Observation of a small vibrational population ratio of Br{sub 2}(v=1)/Br{sub 2}(v=0) agrees with the proposed mechanism.« less
  • Following photodissociation of CH{sub 2}Br{sub 2} at 248 nm, Br{sub 2} molecular elimination is detected by using a tunable laser beam, as crossed perpendicular to the photolyzing laser beam in a ring-down cell, probing the Br{sub 2} fragment in the B {sup 3}{pi}{sub ou}{sup +}-X {sup 1}{sigma}{sub g}{sup +} transition. The nascent vibrational population is obtained, yielding a population ratio of Br{sub 2}(v=1)/Br{sub 2}(v=0) to be 0.7{+-}0.2. The quantum yield for the Br{sub 2} elimination reaction is determined to be 0.2{+-}0.1. Nevertheless, when CH{sub 2}Br{sub 2} is prepared in a supersonic molecular beam under cold temperature, photofragmentation gives no Br{submore » 2} detectable in a time-of-flight mass spectrometer. With the aid of ab initio potential energy calculations, a plausible pathway is proposed. Upon excitation to the {sup 1}B{sub 1} or {sup 3}B{sub 1} state, C-Br bond elongation may change the molecular symmetry of C{sub s} and enhance the resultant 1 {sup 1,3}A{sup '}-X-tilde{sup 1}A{sup '} (or 1 {sup 1,3}B{sub 1}-X-tilde{sup 1}A{sub 1} as C{sub 2v} is used) coupling to facilitate the process of internal conversion, followed by asynchronous concerted photodissociation. Temperature dependence measurements lend support to the proposed pathway.« less