Optimization of Measuring Methods for Methane Clumped Isotopologues 12CH2D2

KeyWord:methane  clumped isotope  high-resolution gas stable isotope ratio mass spectrometer£¨HR£­IRMS£©  precision

Abstract:

      Recently developed methane clumped isotope techniques provide fresh and novel insights into methane production and transformation£¬which have been unobtainable through other techniques such as traditional stable isotope£®Methane clumped isotope techniques have the advantages of high resolution and low detection limit£®13CH3D and 12CH2D2 have their unique chemical and physical properties recording information on methane isotopic equilibrium states£®The measuring methods for paired clumped isotopologues have just been established in China£¬and the precision of ¦Ä12CH2D2 need to be further improved£®Based on the first high-resolution gas stable isotope mass spectrometer£¨HR£­IRMS£© in China£¬the measuring method for 12CH2D2 was optimized by balancing the resolution and sensitivity of the instrument£®The £Û12CH2D2+£Ý intensity was effectively improved£®The analysis precision was successfully improved to 1.29¡ë by using H2O+ peak simulation calculation for the contribution of adjacent 13CH3D and 13CH5 peaks to the total background.