电感耦合等离子体质谱法测定水中重金属含量的不确定度评定

Uncertainty evaluation of heavy metal content determination in water by inductively coupled plasma mass spectrometry

中文关键词:  不确定度  电感耦合等离子体质谱法  重金属  标准物质  标准曲线

英文关键词:uncertainty  inductively coupled plasma mass spectrometry  heavy metal  standard material  standard curve

中文摘要:

      目的 对电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)测定水中6种重金属(铬、铜、镍、锰、镉、铅)及类金属砷7种元素的测量结果不确定度进行评估。方法 根据JJF 1059.1-2012《测量不确定度评定与表示》和CNAS-GL 006: 2018《化学分析中不确定度的评估指南》对测定不确定度的相关要求, 建立了不确定度评定的数学模型, 分析不确定度的主要来源, 并将各分量进行合成。结果 当砷浓度为9.68 μg/L, 置信区间为95%时, 其扩展不确定度为1.39 μg/L (k=2)。标准物质和标准曲线拟合是引入不确定度分量的最主要分量。在实验过程中应选用国家认可的、给定的相对扩展不确定度较小的标准物质，合适的标准曲线范围能提高测量结果准确度。结论 该不确定度评定研究可为ICP-MS测定水中重金属含量的不确定度评定提供参考。

英文摘要:

      Objective To evaluate the uncertainty of content determination of six heavy metals (chromium, copper, nickel, manganese, cadmium and lead) and arsenic in water by inductively coupled plasma mass spectrometry (ICP-MS). Methods According to the relevant requirements of JJF 1059.1-2012 Evaluation and expression of measurement uncertainty and CNAS-GL 006: 2018 Guide for evaluation of uncertainty in chemical analysis for measuring uncertainty, a mathematical model for uncertainty assessment was established, the main sources of uncertainty were analyzed, and the components were synthesized. Results When the arsenic concentration was 9.68 μg/L and the confidence interval was 95%, the expanded uncertainty was 1.39 μg/L (k=2). It was found that standard material and standard curve fitting were the most important components to introduce uncertainty component. In the process of the experiment, the standard material which was approved by the state and given with less uncertainty of relative extension should be selected. Appropriate standard curve range could improve the accuracy of measurement results. Conclusion The uncertainty evaluation study can provide reference for the uncertainty evaluation of ICP-MS in the determination of heavy metal content in water.