改装元素分析-稳定同位素比值质谱联用仪测定固体样品硫同位素

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

本文对元素分析—稳定同位素比值质谱联用仪(EA-IRMS)进行改装,并利用其测定不同形态硫同位素标准物质和样品。结果表明,在色谱柱后加装SO_(2)气体捕集管,可捕集氧化还原产生的SO_(2)气体,并重复调用作为参考气使用,无需外部引入高纯SO_(2)气体,减小了其对仪器管路腐蚀和实验室环境危害;硫酸钡进样量约400μg时,捕集管中的SO_(2)气体可提供至少20次峰中心聚焦;改装后的EA-IRMS系统测试硫同位素标准物质(IAEA-SO-5、IAEA-S-2、IAEA-S-3、EMA-P1),当硫元素进样量为20μg时,δ^(34)S值测试精度达到0.2‰(n=3),4种国际标准物质测量值与真实值相关系数良好(R^(2)=1),表明硫的不同化合物δ^(34) S值可以相互校准,也表明EA-IRMS改装后可以满足硫同位素测试精度的要求。

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 SO_(2)gas trap tube is installed after chromatographic column to trap the SO_(2)gas generated by redox reaction and the captured SO_(2)can be used as reference gas several times,there is no need to introduce high-purity SO_(2)gas externally,which reduces the damage to the instrument pipeline corrosion and laboratory environment.When the amount of barium sulfate is about 400μg,SO_(2)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 20μg,the δ^(34) S value test accuracy achieve 0.2‰(n=3),4 kinds of international standard material measured value and true value have a good correlation coefficient(R^(2)=1),it indicates that the δ^(34) S 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.