电感耦合等离子体质谱法测定高海拔地区地热水中的微量元素

摘要

西藏地区地热水矿化度较高，且西藏地区海拔高分压低，造成电感耦合等离子体质谱／发射光谱仪（ICP －MS ／OES）的工作条件与低海拔地区不同，因此测定样品时无法采用与低海拔地区相同的测定方法。本文通过优化仪器的工作条件、加入内标元素和建立干扰校正方程等方法，消除了低分压和高矿化度的影响，建立了 ICP －MS 同时测定高海拔地区地热水中的12种微量元素的方法，并对地热水中的放射性元素铀进行检测。测定元素校准曲线的相关系数都在0．9995以上，方法检出限为0．012～0．128μg／L，相对标准偏差（RSD）为1．2％～6．8％，样品加标回收率为95．7％～106．5％。结合本课题组前期的研究成果，本文提出，ICP －MS 法更适合较高矿化度地热水中微量和痕量元素的测定，ICP －OES 法则适用于主量元素的测定，两种方法的结合，可建立高海拔地区地热水的分析技术体系。%The mineralization extent of thermomineral water in Tibet is relatively high,together with high altitude and low air pressure,resulting in the differences in the working conditions of Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES)between Tibet and low altitude areas.Therefore,the measuring method in low altitude areas cannot be used in Tibet.By optimizing the working conditions of the instrument,adding internal standard,and establishing an interference correction equation,the influences of low pressure and hyper-salinity are eliminated.Simultaneous determination of 12 trace elements in thermomineral water by ICP-MS was developed in this study.At the same time,the radioactive element uranium in thermomineral water was also detected.Correlative factors of the calibration curve were all above 0.9995.The detection limits of this method were 0.012 -0.128 μg/L,the relative standard deviations were 1.2% -6.8%,and the recoveries of spiked samples were 95.7% -106.5%.Combining with previous findings of this program,ICP-MS is more suitable for measuring trace elements in thermomineral water of hyper-salinity,while ICP-OES is suitable for the determination of major elements.The combination of these two methods can form a system of analytical techniques of thermomineral water in high altitude areas.