原子荧光法测定灌木枝叶中砷的不确定度评定

Uncertainty evaluation of the arsenic in the bush twigs and leaves by atomic fluorescence spectrometry

目的对原子荧光法测定灌木枝叶中砷不确定度进行评定,为实验室质量控制提供理论依据。方法按照测量不确定度评定的通用法则,建立数学模型,计算各分量的不确定度。结果在95%的置信概率下得到其扩展不确定度为0.05mg.kg-1,总砷含量的标准不确定度最终结果为(1.0714±0.05)mg.g-1。结论测量重复性及标准系列溶液配制是该方法不确定度的主要来源,其他分量相对很小可以忽略。

OBJECTIVE To evaluate the uncertainty for the total arsenic in bush twigs and leaves by Atomic Fluorescence Spectrometry,it would provide certain theoretical basis for laboratory quality control.METHODS According to the expression of uncertainty in measurement of universal law,the mathematical model was established.The impact of every uncertainty component for the measurement uncertainty was estimated.RESULTS On the basis of 95% confidence probability.The extended uncertainty of measurement results which was obtained from standard uncertainty synthesis of uncertainties from each source was 0.05mg·kg-1.The final levels of standard uncertainty of total arsenic were（1.0714±0.05）mg·g-1.CONCLUSION The determination repeatability and concentration of standard solution were the primary sources of uncertainty.Other components were relatively so small that they could be ignored.