电感耦合等离子体质谱法测定米豆腐中镉元素的不确定度评价

Uncertainty evaluation of determination of cadmium in rice tofu by inductively coupled plasma mass spectrometry

目的对电感耦合等离子体质谱法测定米豆腐中镉元素的不确定度进行评价。方法样品经微波消解,超纯水定容,用电感耦合等离子体质谱法测定镉含量。分析标准溶液的配制、曲线拟合、样品称量、消解过程、定容体积、仪器测量重复性等影响不确定度的因素,按照JJF 1059.1-2012《测量不确定度评定与表示》中的方法进行合成,计算扩展不确定度。结果扩展不确定度为0.020 mg/kg,不确定度的影响因素从大到小依次为样品消解、样品重复测定、标准溶液配制、标准曲线拟合、样品定容、样品称量。结论本研究为电感耦合等离子体质谱法测量米豆腐中重金属元素的不确定度评价和质量控制提供参考。

Objective To evaluate the uncertainty of determination of cadmium in rice tofu by inductively coupled plasma mass spectrometry（ICP-MS）. Methods The sample was digested by microwave, and the solvent was ultra pure water. The content of cadmium was determined by ICP-MS. Uncertainty components such as preparation of standard solutions, curve fitting, sample weighing, the process of digestion, the volume size, measurement repeatability were analyzed and synthesized according to JJF 1059.1-2012 Evaluation and expression of uncertainty in measurement, and the expanded uncertainty was calculated. Results The expanded uncertainty was 0.020 mg/kg. The factors which affected the uncertainty from large to small were as follows： sample digestion, repeated sample determination, standard solution preparation, standard curve fitting, sample volume determination and sample weighing. Conclusion This research provides reference for the uncertainty evaluation and quality control for measurement of heavy metals in rice tofu by ICP-MS.