ICP-MS法和HPLC-HG-AFS法测定婴幼儿配方奶粉中硒质量浓度不确定度的比较

摘要

The content of selenium in infant formula milk powder was determined by inductively coupled plasma-mass spectrometry (ICP-MS) and liquid chromatography with atomic fluorescence spectrometry,respectively.The sources of uncertainty in the measurement process were comprehensively considered.The various factors that affect the uncertainty were systematically analyzed.A mathematical model for uncertainty evaluation was established and used to comparatively evaluate the uncertainties of the two analytical methods.The major uncertainty sources were sample pretreatment,tandard curve fitting,measurement repeatability and performance of the instruments.The expanded uncertainty of the two methods was obtained respectively by calculating each variable uncertainty and combined uncertainty.The results sho wed that two methods were 0.020 and 0.034 mg/kg (k =2),respectively.%采用电感耦合等离子体质谱法(ICP-MS)和高效液相色谱-氢化物-原子荧光光谱法(HPLC-HG-AFS)分别测定婴幼儿配方奶粉中硒的质量浓度.比较全面地考虑了整个测定过程的不确定度来源,对影响结果不确定度的各个因素作了系统分析,建立了结果不确定度评估数学模型,探讨了其测定结果不确定度,并对评估结果进行比较.分析不确定度的来源主要包括样品前处理过程、测量过程中的随机效应(测量重复性)、性标准工作曲线拟合及测量仪器等引入的不确定度分量.通过合成得到测量结果的合成不确定度,扩展不确定度及测试结果的报告形式.结果表明:ICP-MS法和HPLC-HG-AFS法扩展不确定度(UI)(k=2)为0.016mg/kg和0.024mg/kg.