Modification of Elemental Analysis-Stable Isotope Ratio Mass Spectrometer Combined Instrument for Determination of Sulfur Isotopes in Solid Samples

In this paper, the elemental analysis-stable isotope ratio mass spectrometer (EA-IRMS) is modified to testing different forms of sulfur isotope standard material and sample. A SO2 gas trap tube is installed after chromatographic column to trap the SO2 gas generated by redox reaction and the captured SO2 can be used as reference gas several times, there is no need to introduce high-purity SO2 gas externally, which reduces the damage to the instrument pipeline corrosion and laboratory environment. When the amount of barium sulfate is about 400 μg, SO2 gas in the trap tube can provide at least 20 peak center focus. Modified EA-IRMS system testing sulfur isotope standard material (IAEA-SO-5, IAEA-S-2, IAEA-S-3, EMA-P1), when the sulfur element injection volume is 20 μg, the δ34S value test accuracy achieve 0.2‰(n=3), 4 kinds of international standard material measured value and true value have a good correlation coefficient (R2=1), it indicates that the δ34S value of different compounds of sulfur can be mutual calibration, and the modified EA-IRMS can meet the accuracy requirement of the sulfur isotope test.