石墨炉原子吸收光谱法测定参苓颗粒中铅的不确定度评定

Uncertainty evaluation on the determination of Pb content in Shen ling granules with microwave digestion-graphite furnace atomic absorption spectrophotometry

目的建立微波消解-石墨炉原子吸收光谱法测定参苓颗粒中铅的不确定度评定的方法,分析影响不确定度测量的主要因素。方法采用微波消解法进行样品前处理,石墨炉原子吸收光谱法对参苓颗粒中铅的含量进行测定,建立数学模型,对模型中各不确定因素进行量化处理。结果样品前处理过程是影响测量结果不确定度的主要因素,样品称量、定容等过程带来的不确定度相对较小。对合成不确定度进行计算,当参苓颗粒中铅质量浓度为0.073 mg/kg时,扩展不确定度为0.003 mg/kg(k=2)。结论该评价方法适用于微波消解-石墨炉原子吸收分光光度法测定参苓颗粒中铅含量不确定度的分析。

Objective To study a method of uncertainty evaluation on the determination of Pb in Shenling granules with microwave digestion-graphite furnace atomic absorption spectrophotometry. Methods The concentration of Pb in Shenling granules was detected by graphite furnace atomic absorption spectrophotometry with microwave digestion, the corresponding mathematical model was established, and uncertainty factors in the mathematical model were quantified. Results The preparation of sample are the main factor which affects the uncertainty of measurement result. And weighing of the sample,volume and other processes factors were smaller than other sources on the uncertainty relative.The determination of Pb in Shenling granules was 0.073 mg/kg, the uncertainty was 0.003 mg/kg（k =2）. Conclusionn This evaluation method is suitable to determining the uncertainty of Pb in Shenling granules by microwave digestion-graphite furnace atomic absorption spectrophotometry.