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Gas chromatography flow rates for determining deuterium/hydrogen ratios of natural gas by gas chromatography/high‐temperature conversion/isotope ratio mass spectrometry
Author(s) -
Jia Wanglu,
Peng Ping'an,
Liu Jinzhong
Publication year - 2008
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3641
Subject(s) - chemistry , isotope ratio mass spectrometry , gas chromatography , deuterium , volumetric flow rate , analytical chemistry (journal) , propane , mass spectrometry , methane , chromatography , hydrogen , organic chemistry , thermodynamics , quantum mechanics , physics
The effects of the gas chromatography flow rate on the determination of the deuterium/hydrogen (D/H) ratios of natural gas utilising gas chromatography/high‐temperature conversion/isotope ratio mass spectrometry (GC/TC/IRMS) have been evaluated. In general, the measured δ D values of methane, ethane and propane decrease with increase in column flow rate. When the column flow rate is 1 mL/min or higher, which is commonly used for the determination of D/H ratios of natural gas, the organic H in gas compounds may not be completely converted into hydrogen gas. Based on the results of experiments conducted on a GC column with an i.d. of 0.32 mm, a GC flow rate of 0.6 mL/min is proposed for determining the D/H ratios of natural gas by GC/TC/IRMS. Although this value may be dependent on the instrument conditions used in this work, we believe that correct δ D values of organic compounds with a few carbon atoms are obtained only when relatively low GC flow rates are used for D/H analysis by GC/TC/IRMS. Moreover, as the presence of trace water could significantly affect the determination of D/H ratios, a newly designed inlet liner was used to remove trace water contained in some gas samples. Copyright © 2008 John Wiley & Sons, Ltd.