茶叶中铅含量的测量不确定度评定

Evaluation of the Uncertainty in Measurement of Lead Content in Tea

运用现代统计学理论对电感耦合等离子体质谱法(ICP-MS)测定茶叶中铅的分析结果的测量不确定度来源进行评定,不确定度来源主要有称量过程、定容过程、仪器测定中标准曲线的拟合、测量过程重复性等。采用A类评定和B类评定方法对影响茶叶中铅分析结果的各个不确定度分量进行评定,确定置信概率95%的扩展不确定度,确定分析结果的置信区间为:[2.66,2.86]。

Based on the modern statistical theory,the uncertainty sources of the analytical results of the determination of lead in tea by inductively coupled plasma mass spectrometry(ICP-MS)were analyzed.The uncertainty sources of the analytical results mainly include the weighing process,the constant volume process,the fitting of the standard curve in the instrument measurement,and the repeatability of the measurement process etc.The uncertainty components that affect the results of lead analysis in tea were evaluated by the methods of A and B,and the expanded uncertainty of 95%confidence probability was determined.The confidence interval of the analysis results was determined as[2.66,2.86].