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Isotopes Environ Health Stud

Title:		New methods for fully automated isotope ratio determination from hydrogen at the natural abundance level
Author(s):		Brand WA; Avak H; Seedorf R; Hofmann D; Conradi T;
Address:		"a Finnigan MAT , Bremen , Deutschland"
Journal Title:		Isotopes Environ Health Stud
Year:		1996
Volume:		32
Issue:		2-Mar
Page Number:		263 - 273
DOI:		10.1080/10256019608036319
ISSN/ISBN:		1025-6016 (Print) 1025-6016 (Linking)
Abstract:		"Abstract A variety of methods for measurement of (2)H/(1)H from H(2) are evaluated for their ability to be fully automated and for applicability to automated isotopic analysis of water and organic compounds. Equilibration of water with H(2) gas with the aid of a platinum catalyst has been commercialized into a fully automated sample preparation device. A second and newer technique, involving injecting water, methane, or other volatile organic compounds onto hot chromium in a reactor attached to the dual inlet system of a gas isotope ratio mass spectrometer, can be integrated with a conventional GC-autosampler to allow automated analysis of a variety of substrates. Both techniques result in precisions around 1 per thousand (delta notation) on the VSMOW scale, and are fast and accurate, and with appropriate mass spectrometers require only negligible scaling for the SLAP/VSMOW difference. Several experimental methods which show considerable promise employ 'isotope ratio monitoring' (irm) inlet systems, in which a carrier gas is used for transport of H(2) to the mass spectrometer. Any such method has to address the problem of He ions corrupting the measurement of the H(2) ions. One such approach uses a heated palladium membrane for selective introduction of H(2) into the mass spectrometer, and a second involves modifications to the ion optics to control the stray helium ions. Both approaches have significant limitations that must be overcome before irm techniques can be used in routine applications, in particular for measuring hydrogen isotopes from GC effluents (irm-GCMS)"
Keywords:
Notes:		"PubMed-not-MEDLINEBrand, W A Avak, H Seedorf, R Hofmann, D Conradi, T eng England 1996/08/01 Isotopes Environ Health Stud. 1996 Aug; 32(2-3):263-73. doi: 10.1080/10256019608036319"