石墨炉原子吸收法测定稻谷中铅、镉含量的不确定度评定

Evaluation of Uncertainty in the Determination of Lead and Cadmium Content in Rice by Graphite Furnace Atomic Absorption Spectrometry

目的:探讨石墨炉原子吸收法测定稻谷中铅、镉含量的不确定度影响因素,对不确定度进行评定。方法:对测量结果重复性、样品称量、样品溶液定容、配制标准溶液和拟合标准曲线计算样品含量引入的不确定度进行分析计算。结果:稻谷中铅含量为(0.080±0.013)mg·kg^(-1),k=2;镉含量为(0.091±0.009)mg·kg^(-1),k=2。结论:测量稻谷中铅、镉含量的不确定度影响因素一致,拟合标准曲线计算样品含量和标准溶液配制引入的不确定度影响最大。

Objective:To explore the factors affecting the uncertainty of the determination of lead and cadmium content in rice by graphite furnace atomic absorption spectrometry,and to evaluate the uncertainty.Method:Analyze and calculate the uncertainty introduced by the repeatability of measurement results,sample weighing,constant volume of sample solution,preparation of standard solution,and fitting of standard curve to calculate sample content.Result:The lead content in rice is(0.080±0.013)mg·kg^(-1),k=2;the cadmium content is(0.091±0.009)mg·kg^(-1),k=2.Conclusion:The uncertainty influencing factors for measuring lead and cadmium content in rice are consistent,and the uncertainty introduced by fitting standard curves to calculate sample content and preparing standard solutions has the greatest impact.