title: Demonstration of compound-specific isotope analysis of hydrogen isotope ratios in chlorinated ethenes.
abstract: High-temperature pyrolysis conversion of organic analytes to H(2) in hydrogen isotope ratio compound-specific isotope analysis (CSIA) is unsuitable for chlorinated compounds such as trichloroethene (TCE) and cis-1,2-dichloroethene (DCE), due to competition from HCl formation. For this reason, the information potential of hydrogen isotope ratios of chlorinated ethenes remains untapped. We present a demonstration of an alternative approach where chlorinated analytes reacted with chromium metal to form H(2) and minor amounts of HCl. The values of δ(2)H were obtained at satisfactory precision (± 10 to 15 per thousand), however the raw data required daily calibration by TCE and/or DCE standards to correct for analytical bias that varies over time. The chromium reactor has been incorporated into a purge and trap-CSIA method that is suitable for CSIA of aqueous environmental samples. A sample data set was obtained for six specimens of commercial product TCE. The resulting values of δ(2)H were between -184 and +682 ‰, which significantly widened the range of manufactured TCE δ(2)H signatures identified by past work. The implications of this finding to the assessment of TCE contamination are discussed.
authors.affiliation: School of Geology and Geophysics, University of Oklahoma, 100 E. Boyd Street, SEC 710, Norman, Oklahoma 73019, United States. tkuder@ou.edu
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kuder
authors.forename: Paul
authors.initials: P
authors.lastname: Philp
mesh_terms: D001554:Benzene / Q000032:analysis; D002247:Carbon Isotopes; D002849:Chromatography, Gas; D004000:Dichloroethylenes / Q000032:analysis; D004777:Environment; D005030:Ethylenes / Q000032:analysis*; D054879:Halogenation; D006859:Hydrogen / Q000032:analysis*; D007553:Isotope Labeling / Q000379:methods*; D013058:Mass Spectrometry; D012015:Reference Standards; D014241:Trichloroethylene / Q000032:analysis; D035501:Uncertainty
chemical_list: D002247:Carbon Isotopes; D004000:Dichloroethylenes; D005030:Ethylenes; D014241:Trichloroethylene; D006859:Hydrogen; C036216:ethylene; D001554:Benzene; C035384:1,2-dichloroethylene