石墨炉原子吸收光谱法测定葛根粉中铅的不确定度评定

Uncertainty Evaluation for the Determination of Plumbum in Kudzuvine Root Powder by Graphite Furnace Atomic Absorption Spectrometry

目的:采用石墨炉原子吸收光谱法对葛根粉中铅含量进行测定,并对检测结果不确定度进行评定与表示。方法:通过表述铅的测量程序,列出和量化影响不确定度的主要分量,计算合成标准不确定度和扩展不确定度。结果:石墨炉原子吸收光谱法测定葛根粉中铅的含量(以Pb计)为(0.032±0.014)mg·kg^(-1)(k=2)。结论:对铅的测量不确定度影响较大的两组分量为标准曲线拟合和重复测定,空白试验观测值对痕量分析结果影响较大,合理设计标准曲线和优化标准曲线拟合、规范实验操作和控制测量精密度可以减小测量不确定度。

Objective:To determine the lead content in kudzuvine root powder by graphite furnace atomic absorption spectrometry,and to evaluate and express the uncertainty of the result.Method:By describing the measuring procedure of lead,the main components of influencing uncertainty were listed and quantified,and the synthetic standard uncertainty and extended uncertainty were calculated.Result:The content of Pb in kudzuvine root powder measured by graphite furnace atomic absorption spectrometry was(0.032±0.014)mg·kg^(-1)(k=2).Conclusion:Standard curve fitting and parallel multiple measurements are the two components that have a great influence on the measurement uncertainty of lead.The observation value of blank test has a significant influence on the trace analysis results.Reasonable design of standard curve and optimization of standard curve fitting,standardized experimental operation and control of measurement precision can reduce the measurement uncertainty.