Abstract: The measurement uncertainty was estimated for the determination of calcium and magnesium in milk using microwave plasma torch atomic emission spectrometry (MPT-AES) and the uncertainty parameters were discussed and compared in detail. The results show that the "whole method" performance parameters, such as precision and recovery, and sampling are the three main contributors to uncertainty. In addition, the content of calibration solution is the main contributor to measurement uncertainty in the determination of magnesium. When coverage factor k=2 and confidence level approximately 95%, the expanded uncertainties were determined as 18.6 and 3.2 mg/L for Ca and Mg, respectively.

Key words: Microwave plasma torch-atomic emission spectrometry , Measurement uncertainty ,  Milk ,  Calcium ,  Magnesium

摘要： 　    研究了微波等离子体原子发射光谱法测定钙、镁质量浓度的各种不确定度因素，评定了该方法测定钙、镁质量浓度的不确定度。实验结果表明，两个综合性因素（方法的精密度和准确度）以及取样过程是方法不确定度的主要来源，另外，校准溶液浓度的不确定度是评定镁质量浓度不确定度的主要来源；在置信水平为９５％和包含因子ｋ＝２的条件下，测定钙、镁质量浓度的扩展不确定度分别为１８．６和３．２ｍｇ／Ｌ。

关键词: 　微波等离子体原子发射光谱法 , 　测量不确定度 , 　牛奶 , 　钙 , 　镁