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目的分析电感耦合等离子体质谱法(ICP-MS)测定紫菜中砷(As)、镉(Cd)含量的不确定度来源,提高检测结果的准确性。方法主要对样品称量、样品消解、样品定容、样品溶液中元素的测定、样品均匀性等因素进行分析,确定不确定度来源,计算合成不确定度。结果本方法测定紫菜中As、Cd含量的扩展不确定度分别为5.081、0.138 mg·kg~(-1),其不确定度的主要来源为元素浓度的测定过程。结论该方法适用于紫菜粉中As、Cd含量的不确定度评定。
Objective To analyze the sources of uncertainty of determination of arsenic (As) and cadmium (Cd) in seaweed by inductively coupled plasma mass spectrometry (ICP-MS), and to improve the accuracy of the detection results. The method mainly analyzes the factors such as sample weighing, sample digestion, sample volume determination, elemental determination in sample solution, sample homogeneity and other sources to determine the uncertainty and calculate the synthesis uncertainty. Results The results showed that the uncertainty of determination of As and Cd in seaweed was 5.081 and 0.138 mg · kg -1, respectively. The main source of uncertainty was determination of elemental concentration. Conclusion The method is suitable for the evaluation of the uncertainty of As and Cd content in seaweed powder.