ICP-MS法测量乳中重金属铅含量的不确定度评定

Uncertainty evaluation of determination of Pb content in milk by ICP-MS.

根据GB 5009.268-2016《食品安全国家标准食品中多元素的测定》第一法电感耦合等离子体质谱仪法[1]来测定生鲜乳质控样中铅含量。通过分析检测过程建立数学模型,对模型中各影响因素的不确定度进行评定和计算,合成相对标准不确定度,计算扩展不确定度。结果表明,当取置信概率为95%时,最终得到铅元素的测量扩展不确定度U=0.03mg/kg(k=2),即该生鲜乳质控样重金属铅含量的结果x=(0.247±0.03)mg/kg(k=2)。

The determination is carried out according to GB 5009.268-2016.A mathematical model for the analysis was set up,the uncertainty of each influencing factor in the model is evaluated and calculated,the relative standard uncertainty is synthesized,and the expanded uncertainty is calculated.The results show that the confidence probability is 95%,the extended uncertainty of Pb is U=0.03mg/kg(k=2),the result of Pb content in the milk quality control sample is x=(0.247±0.03)mg/kg(k=2).