封闭酸溶样ICP-MS法直接测定地质样品中镓、铟、铊、锗

Determination of gallium,indium,thallium and germanium in geological samples after pressurized acid digestion by inductively coupled plasma mass spectrometry

采用封闭酸溶的低空白、元素挥发少的特点以及ICP-MS多元素同时分析的优势,建立了封闭酸溶样ICP-MS法直接测定稀散元素Ga,In,Tl,Ge的分析方法。考察了实验过程中的水、气以及试剂空白对元素信号的影响情况;对比了敞开酸溶、封闭酸溶与微波消解3种样品消解效果;探讨了各元素分析同位素的选择及其质谱干扰校正。在优化的实验条件下,Ga,In,Tl和Ge方法检出限分别为0.78,0.05,0.04和0.06μg/g。测定了GSR系列12个国家标准物质中的Ga,Ge,In,Tl,各元素测定值均与其推荐值吻合,RSD(n=5)均在8%以内。

In a conventional method,scattered elements analysis in geological samples often needs to combine several methods due to the different elements and contents. In this paper we established a method for direct detection of Ga,In,Tl and Ge by taking advantage of low reagents blank and volatility during pressurized acid digestion and multi-element simultaneous determination in ICP-MS. We investigated the influence of water,air and reagent blank on the signal intensity,compared the digestion efficiency of the open acid digestion system,pressurized acid digestion and microwave digestion,and discussed the selection of each isotope and mass spectrum interference correction. Under the optimized experimental conditions,the detection limits of the method for Ga,In,Tl and Ge were 0. 78,0. 05,0. 04 and 0. 06 μg / g respectively. The method was applied to the determination of Ga,In,Tl and Ge in GSR series national standard samples. Analysis results agreed well with the standard values with all the relative standard deviations（ RSD,n = 5） within 8%.