微波消解-石墨炉原子吸收法测定茶叶中铅含量的测量不确定度评定

Uncertainty Evaluation of Determination of Pb in Tea by Graphite Furnace Atomic Absorption Spectrophotometry with Microwave Digestion

[目的]研究微波消解-石墨炉原子吸收法测定茶叶中铅含量的测量不确定度评定方法。[方法]试验采用微波消解的前处理方法,对茶叶中的铅含量用石墨炉原子吸收光谱法进行测定,建立了相应的数学模型,对数学模型中各种不确定因素进行量化处理。[结果]研究表明,不确定度的主要来源为标准溶液配制、样品称量、容量器具的体积、标准曲线拟合、重复性测定等,茶叶中铅的测量不确定度测定结果为(1.90±0.11)mg/kg。[结论]该评定方法可用于微波消解-石墨炉原子吸收法测定茶叶中铅含量的测量不确定度分析,保证测量结果的准确、可靠。

[ Objective ] To study on uncertainty evaluation of determination of Pb in tea by graphite furnace atomic absorption spectrophotometry with microwave digestion. [ Method] To detect the determination of Pb in tea by graphite furnace atomic absorption spectrophotometry with microwave digestion, corresponding mathematical model was established, and uncertainty factors in the mathematics model were quantified. [ Results ] The result indicated that standard solution, weighing, the volume of a volumetric apparatus, standard curve fitting and repeatability are the main sources of uncertainty. The result of the determination of Pb in tea was （ 1.90 ±0.11 ） mg/kg. [ Conclusion] This method can be used to determine the uncertainty analysis of Pb in tea by graphite furnace atomic absorption spectrophotometry with microwave digestion, to make the determination results more accurate and reliable.