石墨炉原子吸收光谱法测定尿铅的不确定度分析

目的分析石墨炉原子吸收光谱法测定尿铅过程中不确定度的主要来源,找出关键的影响因素,为实验室质量控制提供一定的理论依据。方法采用石墨炉原子吸收光谱法测定尿液中铅的浓度,同时构建数学模型,对各部分分量进行分析。结果对于尿样中铅浓度为25.15μg/ml的样品,取包含因子k=2,其扩展不确定度为1.2μg/ml,最终报告尿铅含量（334.5±12.0）μg/L;同时对影响测定结果的不确定度的各部分因素进行了量化,标准储备液及稀释校准过程引入的不确定度u（sta）为5.13×10^-3;样品制备过程引入的不确定度u（pre）为4.56×10^-3;标准曲线拟和引入的不确定度u（C0）为0.0187;重复条件下的标准偏差u（ ）为3.60×10^-3。结论影响尿铅测定结果不确定度的主要因素是工作曲线拟合引入的误差。

Analysis of the uncertainty in the determination of the lead in human urine by graphite furnace atomic absorption spectrographic method

Objective Analysis of the uncertainty in the measurement of lead in human urine by graphite furnace atomic absorption spectrometer was intreduced in this article.The sources of uncertainty and their effects on the total uneertainty were also analyzed.Methods Construct the mathematical model for evaluation of uncertainty in measurement based on a comprehensive understanding of the whole procedure of the determination.Results The measurement result of lead in human urine was given as (334.5±12.0)μg/L.Conclusions The major factor in influence on the determination of lead in human urine was the working curve fitting introduction error.