天然气单体烃氢同位素组成质谱分析

用色谱 -热转换 -质谱 ( GC/ TC/ MS)对天然气单体烃氢同位素组成进行了测定。实验表明 :热转换温度、进样量和分流比等条件的改变对氢同位素组成的测量结果有影响。以文 3 1井甲烷氢同位素组成 ( -1 5 4‰ )为参考 ,对天然气中甲烷、乙烷和丙烷氢同位素组成的测量不确定度进行了分析。结果表明 :甲烷和乙烷的测量精度都较高 ,但由于参考标准的不确定度较大 ,所以测量结果的不确定度较大

Analysis of Hydrogen Isotopic Composition in Single Hydrocarbon by Mass Spectrometry

The hydrogen isotopic compositions in single hydrocarbons was measured by gas chromatography-thermoconversion-mass spectrometry (GC/TC/MS). The results showed that the temperature in the reactor, the gas amount injected into GC and the split ratio of natural gas injected into GC inlet affect the determination result of the hydrogen isotopic composition. Using the certified reference natural gas, the hydrogen isotopic of methane in Wen31 well is δD v-smow= -154‰. The uncertainties of the hydrogen isotopic measurement of methane, ethane and propane were researched. Although their measuring standard deviation is less, the uncertainty of results is larger because of the larger uncertainty of the certified reference natural gas.