微波消解-AFS法测定婴幼儿配方奶粉中硒的测量不确定度评定

Uncertaintiy Evaluation in the Measurement of Selenium in Milk Powder for Infant and Young Children with Microwave Digestion-AFS

建立微波消解-AFS法测定婴幼儿配方奶粉中硒含量的测量不确定度的测量模型,根据模型分析并计算不确定度各个分量、结果的不确定度以及扩展不确定度。结果表明,引起测量不确定度的最主要来源是测定C值时用最小二乘法拟合标准工作曲线所引入的不确定度。计算得到在婴幼儿奶粉中硒含量为0.310 mg/kg时,扩展不确定度为0.046 mg/kg,包含因子k为2。该方法适用于婴幼儿配方奶粉中硒含量的测量不确定度评定。

A measurement model was established, the independent uncertainty, standard uncertainty and ex- panded uncertainty coming from analysis procedure were obtained. The major source of the uncertainty was the calibration curve calculated on the basis of the principle of method of least squares when determining C. As sele nium content in milk powder for infant and young children was 0.310 mg/kg, the expanded uncertainty was 0.046 mg/kg and the coverage factor k was 2. This method was suitable for evaluating the uncertainties in the measurement of selenium in milk powder for infant and young children.