石墨炉原吸光谱法测定土壤铅的不确定度评定

Evaluation of Uncertainty in Determination of Lead in Soil by Graphite Furnace Atomic Absorption Spectroscopy

论述以石墨炉原子吸收光谱法测定土壤中铅的方法原理和分析过程,通过应用数理统计学中最小二乘法建立回归方程,在回归方程基础上建立数学模型,针对标准物质、标准曲线、样品消解过程、重复测定等分析过程识别不确定度的来源和因素,并加以评定分析,得出利用石墨炉原子吸收仪测定土壤中铅的浓度为x′=25.9 mg/kg时,扩展不确定度为U=2.22 mg/kg,k=2,并给出测量不确定评定报告。

The methodology and analytical process for the determination of lead in soil by graphite furnace atomic absorption spectroscopy were described.A regression equation was established by applying the least squares in the mathematical statistics and a mathematical model was established on the basis of the regression equation,the sources and factors of uncertainty were identified and evaluated for reference materials,standard curve,sample digestion process,repeated determination,etc.it was concluded that the expanded uncertainty was given as U=2.22 mg/kg,k=2,when the lead concentration in soil was determined by graphite furnace atomic absorption spectrometry as x′=25.9 mg/kg,and the evaluation report of measurement uncertainty was given.