氢化物-原子荧光光谱法测定地质样中的痕量硒--不同溶样方式的比较

以确定测试基性岩中痕量硒的最佳溶样方式为目的，分别采用加压（PTFE）强酸消解和常压强酸消解两种方法消解标准参考物质和地质样品，直接用氢化物原子荧光光谱法（HG-AFS）测定。实验选用标准参考物质GWB07105、GWB07107对方法准确度和精确度进行验证，所测得总硒量与推荐值相符，标准偏差（SD）小于7．3ng／g，相对标准偏差（RSD）小于8．9％。实验测定了5个硒含量不同的岩石样品，不同方法所测数据基本一致。样品的均匀性在一定程度上影响痕量硒的测定结果。综合评价比较二者的测定结果，可知加压（PTFE）强酸消解（硝酸＋硫酸＋氢氟酸）为最佳溶样方式。

Determination of Trace Selenium in Geological Samples by Hydride Generation Atomic Fluorescence Spectrometry--A Comparative Experiment of Two Different Dissolution Methods

A comparative experiment of two different dissolution methods was carried out for the purpose of selecting the most effective method for dissolving basic rock samples. The referencing standard materials and rock samples were dissolved by strong acid under atmospheric pressure and under the pressure higher than the atmospheric one respectively, in order to prepare solutions for determining trace selenium by hydride generation atomic fluorescence spectrometry (HG-AFS). The referencing standard materials (GWB07105, GWB07107) were applied for verifying the analytical accuracy and precision. The analytical results of their total selenium contents are in accordance with the referencing values with the standard deviation(SD)of less than 7. 3 ng/g and relative standard deviation (RSD) of 8. 9 % ( n = 3) respectively. Then five geological samples were dissolved by the above two methods respectively to prepare solutions for analyzing their total selenium contents with the analytical contents varying from 74. 5 ng/g to 277. 6 ng/g. The analytical results of solutions prepared by different methods using same samples are very similar. The analytical values could be affected in some extent by the homogenization degrees of samples. In general, the most effective way of dissolving samples is believed to be the strong acid ( HNO3+ H2SO4+ HF) dissolution under the applied pressure.