Online methodology for determining compound‐specific hydrogen stable isotope ratios of trichloroethene and 1,2‐<i>cis</i>‐dichloroethene by continuous‐flow isotope ratio mass spectrometry

Shouakar-Stash, Orfan; Drimmie, R.J.

doi:10.1002/rcm.6578

Cited by 15 publications

(14 citation statements)

References 45 publications

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“…The inability of traditional off‐line and conventional HTC methods to quantitatively generate H 2 and accurately measure δ 2 H values of halogenated organic compounds prompted the development of chromium‐based reactor systems that are not affected by incomplete H 2 yields and isotope fractionation. The underlying principle of chromium‐HTC (Cr/HTC) applications is chrome's ability to quantitatively scavenge carbon, nitrogen, oxygen, sulfur and halogens (F, Cl, Br, I) at elevated temperatures while quantitatively releasing H 2 into the carrier stream of an inert noble gas …”

Section: δ2h Values For N‐alkane and Diverse Halogen‐bearing Referencmentioning

confidence: 99%

Compound‐specific hydrogen isotope analysis of fluorine‐, chlorine‐, bromine‐ and iodine‐bearing organics using gas chromatography–chromium‐based high‐temperature conversion (Cr/HTC) isotope ratio mass spectrometry

Renpenning

Schimmelmann

Gehre

2017

Rapid Comm Mass Spectrometry

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Section: δ2h Values For N‐alkane and Diverse Halogen‐bearing Referencmentioning

confidence: 99%

Compound‐specific hydrogen isotope analysis of fluorine‐, chlorine‐, bromine‐ and iodine‐bearing organics using gas chromatography–chromium‐based high‐temperature conversion (Cr/HTC) isotope ratio mass spectrometry

Renpenning

Schimmelmann

Gehre

2017

Rapid Comm Mass Spectrometry

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“…Analytical techniques for CSIA evolved to include the evaluation of carbon, chlorine, and nitrogen isotope ratios of organic compounds that are often targets of remediation efforts . These, combined with the hydrogen CSIA of chlorinated contaminants, − can provide useful information to discriminate between reaction mechanisms . Large primary isotope effects, due to large differences in bond strength of 1 H vs 2 H, can be expected where hydrogen is directly involved in the rate-limiting step (e.g., carbon–hydrogen bond oxidation) .…”

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confidence: 99%

Requirements for Chromium Reactors for Use in the Determination of H Isotopes in Compound-Specific Stable Isotope Analysis of Chlorinated Compounds

et al. 2020

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There is a strong need for careful quality control in hydrogen compound-specific stable isotope analysis (CSIA) of halogenated compounds. This arises in part due to the lack of universal design of the chromium (Cr) reactors. In this study, factors that optimize the critical performance parameter, linearity, for the Cr reduction method for hydrogen isotope analysis were identified and evaluated. These include the effects of short and long vertically mounted reactors and temperature profiles on trapping of Cl to ensure accurate and precise hydrogen isotope measurements. This paper demonstrates the critical parameters that need consideration to optimize any Cr reactor applications to ensure the accuracy of δ2H analysis for organic compounds and to enhance intercomparability for both international standards and reference materials run by continuous flow versus an elemental analyzer.

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“…However, the C 2 HCl 2 isotopomer signatures of technical and environmental DDD formation respectively induce more positive or negative whole-molecule δ 2 H values of DDD, as compared to DDT. Compound-specific IRMS methods for δ 2 H measurements for polyhalogenated compounds [29] , [30] have recently been introduced; therefore comparison of δ 2 H values of DDD and DDT may allow tracing sources of DDD to technical synthesis or breakdown of DDT in the environment.…”

Section: Resultsmentioning

confidence: 99%

Elucidating Turnover Pathways of Bioactive Small Molecules by Isotopomer Analysis: The Persistent Organic Pollutant DDT

et al. 2014

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The persistent organic pollutant DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) is still indispensable in the fight against malaria, although DDT and related compounds pose toxicological hazards. Technical DDT contains the dichloro congener DDD (1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethyl]benzene) as by-product, but DDD is also formed by reductive degradation of DDT in the environment. To differentiate between DDD formation pathways, we applied deuterium NMR spectroscopy to measure intramolecular deuterium distributions (2H isotopomer abundances) of DDT and DDD. DDD formed in the technical DDT synthesis was strongly deuterium-enriched at one intramolecular position, which we traced back to 2H/1H fractionation of a chlorination step in the technical synthesis. In contrast, DDD formed by reductive degradation was strongly depleted at the same position, which was due to the incorporation of 2H-depleted hydride equivalents during reductive degradation. Thus, intramolecular isotope distributions give mechanistic information on reaction pathways, and explain a puzzling difference in the whole-molecule 2H/1H ratio between DDT and DDD. In general, our results highlight that intramolecular isotope distributions are essential to interpret whole-molecule isotope ratios. Intramolecular isotope information allows distinguishing pathways of DDD formation, which is important to identify polluters or to assess DDT turnover in the environment. Because intramolecular isotope data directly reflect isotope fractionation of individual chemical reactions, they are broadly applicable to elucidate transformation pathways of small bioactive molecules in chemistry, physiology and environmental science.

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Online methodology for determining compound‐specific hydrogen stable isotope ratios of trichloroethene and 1,2‐cis‐dichloroethene by continuous‐flow isotope ratio mass spectrometry

Cited by 15 publications

References 45 publications

Compound‐specific hydrogen isotope analysis of fluorine‐, chlorine‐, bromine‐ and iodine‐bearing organics using gas chromatography–chromium‐based high‐temperature conversion (Cr/HTC) isotope ratio mass spectrometry

Compound‐specific hydrogen isotope analysis of fluorine‐, chlorine‐, bromine‐ and iodine‐bearing organics using gas chromatography–chromium‐based high‐temperature conversion (Cr/HTC) isotope ratio mass spectrometry

Requirements for Chromium Reactors for Use in the Determination of H Isotopes in Compound-Specific Stable Isotope Analysis of Chlorinated Compounds

Elucidating Turnover Pathways of Bioactive Small Molecules by Isotopomer Analysis: The Persistent Organic Pollutant DDT

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