Compound-specific hydrogen isotope analysis of heteroatom-bearing compounds via gas chromatography-chromium-based high-temperature conversion (Cr/HTC)-isotope ratio mass spectrometry.
The traditional high-temperature conversion (HTC) approach toward compound-specific stable isotope analysis (CSIA) of hydrogen for heteroatom-bearing (i.e., N, Cl, S) compounds has been afflicted by fractionation bias due to formation of byproducts HCN, HCl, and H2S. This study presents a chromium-based high-temperature conversion (Cr/HTC) approach for organic compounds containing nitrogen, chlorine, and sulfur. Following peak separation along a gas chromatographic (GC) column, the use of thermally stable ceramic Cr/HTC reactors at 1100-1500 °C and chemical sequestration of N, Cl, and S by chromium result in quantitative conversion of compound-specific organic hydrogen to H2 analyte gas. The overall hydrogen isotope analysis via GC-Cr/HTC-isotope ratio mass spectrometry (IRMS) achieved a precision of better than ± 5 mUr along the VSMOW-SLAP scale. The accuracy of GC-Cr/HTC-IRMS was validated with organic reference materials (RM) in comparison with online EA-Cr/HTC-IRMS and offline dual-inlet IRMS. The utility and reliability of the GC-Cr/HTC-IRMS system were documented during the routine measurement of more than 500 heteroatom-bearing organic samples spanning a δ(2)H range of -181 mUr to 629 mUr.
Department for Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research-UFZ , Permoserstrasse 15, D-04318 Leipzig, Germany.
Julian
J
Renpenning
Department for Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research-UFZ , Permoserstrasse 15, D-04318 Leipzig, Germany.
Steffen
S
Kümmel
Department for Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research-UFZ , Permoserstrasse 15, D-04318 Leipzig, Germany.
Kristina L
KL
Hitzfeld
Department of Geological Sciences, Indiana University , Bloomington, Indiana 47405-1405, United States.
Arndt
A
Schimmelmann
Department for Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research-UFZ , Permoserstrasse 15, D-04318 Leipzig, Germany.
Matthias
M
Gehre
D002857:Chromium / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D013696:Temperature
D002857:Chromium; D003903:Deuterium