X-射线荧光光谱法测定石灰石中三种组分含量的不确定度评定

Evaluation of Uncertainty in Determinations of Six Components in Limestone by X-Ray Fluorescence Spectrometry

采用压片制样-X射线荧光光谱法测定石灰石中氧化钙、氧化镁和二氧化硅的含量,分析了测量结果的不确定度来源。对测量重复性、标准物质、工作曲线变动性、制样因素、检测环境和仪器稳定性引起的不确定度分量进行评定,计算了合成标准不确定度和扩展不确定度。评定结果表明,工作曲线变动性引入的不确定度分量对总的不确定度影响最大。

The contents of calcium oxide,magnesium oxide and silicon dioxide in limestone were determined by X-ray fluorescence spectrometry with pressed powder pellet. The sources of the uncertainty were analyzed. The factors influencing the uncertainty of determination results were evaluated,such as measurement repeatability,reference material,variability of working curve,sample preparation,testing environment and stability of instrument. Based on the results,combined relative standard uncertainty and expanded uncertainty were calculated. The evaluation results indicated that the uncertainty caused by the variability of working curve had the greatest influence on the total uncertainty.