电感耦合等离子体质谱法测定食品中铅的不确定度评定

Uncertainty evaluation for the determination of lead in food by inductively coupled plasma-mass spectrometry

目的评定电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测定食品中铅的不确定度。方法根据GB 5009.12《食品安全国家标准食品中铅的测定》,采用电感耦合等离子体质谱法测定食品中铅,根据不确定度评定规程,建立不确定度评定的数学模型,系统性评价测量过程的不确定度。结果当食品中铅含量为0.333mg/kg时,其扩展不确定度为0.03mg/kg(P=95%,k=2),测定结果为(0.333±0.03) mg/kg。结论标准曲线拟合引入的不确定度是食品中铅测量不确定度的主要贡献因子。

Objective To evaluate the uncertainty of determination of lead in food by inductively coupled plasma-mass spectrometry(ICP-MS).Methods Based on the method of GB 5009.12—2017“National food safety standard determination of lead in foods”,the lead in food was measured by ICP-MS.According to the evaluation rules of uncertainty,the mathematical model of uncertainty evaluation was established,then the systematic evaluation of uncertainty was evaluated in the whole measurement process.Results When the concentration of lead in food was 0.333 mg/kg,the expanded uncertainty was 0.03 mg/kg and the result was expressed as(0.333±0.03)mg/kg。Conclusion The uncertainty introduced by standard curve fitting is the main factor contributing to the uncertainty of the measurement of lead in food.