High pure CO2 gas was tested in different intensity through MAT253&GasBench to determine the relationship between CO2 intensity and its isotope ratio under different extractions.10 points’ trend lines show that relative variations of 4544 are-0.06‰,-0.03‰ and-0.005‰ respectively,corresponding to the extraction values of 15%,50% and 95%,with sensitivity’s slight decreasing.The results show that extraction forms main influence on the linearity of gas isotope mass spectrometer,and that the best linearity can be found when using high percent value of extraction.Emission,trap voltage and electron energy are indirect factors to slightly affect linearity,extraction should properly match them to acquire better linearity,because they influence the ions ratio to some extent during the ionization.
