原子吸收法测定泡菜中铅含量的不确定度评定

目的采用原子吸收法对泡菜中铅含量进行测定不确定度评定。方法对泡菜中铅含量测定过程中各影响因素,包括称量、标准溶液配制、微波消解过程、仪器、标准曲线拟合等进行分析评定。结果该方法检测泡菜中铅的合成不确定度为3.02%,扩展不确定度为6.04%。本实验测定的泡菜中铅含量结果为(2.46±0.15)mg/kg(P=95%,k=2)。结论本实验的不确定度主要由微波消解过程、标准曲线拟合和仪器允差引入。

Uncertainty evaluation for determination of lead in pickled vegetables by atomic absorption spectrometry

Objective To evaluate the uncertainty in determination of lead in pickled vegetables by atomic absorption spectrometry (AAS). Methods The uncertainty caused by various factors in the whole process of determination was analyzed, including weighing, solution preparation, microwave digestion, the apparatus and calibration fitting. Results The synthetic uncertainty in determination of lead in pickled vegetables was 3.02% and the expanded uncertainty was 6.04%. The content of lead in pickled vegetables was (2.46±0.15) mg/kg (P=95%, k=2). Conclusion The uncertainty of this method is mainly caused by microwave digestion, calibration fitting and AAS error.