塑料中镉的测定不确定度评定

Study on estimation of uncertainty in measurement of cadmium element in plastics

建立了用实验室内精密度和偏差的数据来评定塑料中镉的测定不确定度的方法。通过研究不同基体和不同含量水平的样品,考察了方法的精密度和回收率,分别计算并合并了两者的测量不确定度。结果表明精密度和回收率的相对不确定度分量分别为0.026和0.068,合成不确定度为0.072,扩展不确定度为0.14。此评定过程为实验室评定测量不确定度提供了一种新的方法,简单、合理,计算结果可靠。

A novel method was established to estimate the uncertainty in the measrement of Cadmium in plastics by Flame Atomic Absorption Spectrometry （FAAS） based on the repeatability and bias data within laboratory in this paper. A representative range of samples covering typical matrices and Cadmium concentration levels were employed to investigate the whole method performance parameters of method precision and method recovery, and the measurement uncertainty of both parameters were calculated, respectively, and then combined. The results reveal that the individual uncertainty of precision and recovery is, respectively, 0.026 and 0.068, the combined measurement uncertainty is 0. 072, and the expanded uncertainty is 0.14. This procedure of estimation of measurement uncertainty provides a new method for estimation of measurement uncertainty for analytical laboratory, and it is simple, reasonable and the result is reliable.