目的 通过分析实验中的各不确定度分量,评定测量结果的不确定度。方法 使用GB/T5009.12-2010采用石墨炉原子吸收法测定大米中的铅,参照JJF 1059.1-2012建立数学模型,对每个不确定分量进行评估。结果 通过对每个不确定度分量的计算,得出最终扩展不确定度为0.030 mg/kg(包含因子k=2),结果报告为0.70±0.030 mg/kg。结论 石墨炉原子吸收法测定大米中铅,对不确定度影响较大的主要为重复性引入的不确定度和拟合曲线引入的不确定度。

Objective To evaluate uncertainty of measurement results by analyzing the uncertainty components in the experiment. Methods The lead in rice was determined by graphite furnace atomic absorption according to GB/T5009.12-2010. The mathematical model was established according to JJF 1059.1-2012 to evaluate each uncertainty component. Results By the calculation of each uncertainty component, it was concluded that eventually extended uncertainty was 0.030mg/kg (including factor k=2), the report result was (0.70±0.030) mg/kg. Conclusion The uncertainty were mainly influenced by uncertainties in the introduction of repeatability and fitting curve