X射线荧光光谱法测定高锶高钡的硅酸盐样品中主量元素

用百分总和检查硅酸盐岩石全分析数据的质量是分析工作者的传统做法,但对于微量元素含量较高的样品,采用X射线荧光光谱法(XRF)进行测定,如果不考虑微量元素的含量及其对主量元素基体效应的影响,往往会使主量元素含量更加偏离真实值。本文针对Sr、Ba含量较高的硅酸盐样品,通过人工配制标准样品,扩大了Sr、Ba校准曲线的定量范围,主量元素校准中加入Sr、Ba的基体校正系数,达到了主量元素定量更加准确可靠的实际效果。采用此方法分析国家标准物质,各主量元素的精密度(RSD)均小于2%;分析不参加回归的标准物质和人工配制的标准样品,主量元素的测量值与标准值(或参考值)基本一致。该方法可以满足硅酸盐的测定要求,主量元素各项结果的加和能够达到《地质矿产实验室测试质量管理规范》的一级标准(99.3%～100.7%)。

Determination of Major Elements in Silicate Samples with High Content Strontium and Barium by X-ray Fluorescence Spectrometry

Traditionally, the percentage sum method is used to check the data quality of total analysis of constituents for silicate rock. For samples with a high content of trace elements, the contents of major elements obtained by X-ray Fluorescence Spectrometry (XRF) will deviate from the true values, regardless of trace elements, as will its corresponding matrix effect to the major element. The method described in this paper improves the accuracy of major element content in silicate samples with a high content of Sr and Ba, through extending the calibration curve's quantitative range of Sr and Ba by Chinese National Standard Materials and artificial standard materials, and applying a matrix correction coefficient of Sr and Ba to the major element calibration procedure. The validity of the method was substantiated by analyzing the national standard materials; the relative standard deviations (RSD) of major elements were less than 2%. Additionally, analysis results of major elements of national standard materials and artificial standard materials, which do not participate in regression were basically in accordance with reference contents. The method can be used to satisfy the analysis of silicate rock and the sum results of all major elements meet the standard of specification of testing quality management for geological laboratories (99.3% to 100.7%).