火焰原子吸收分光光度法测定精对苯二甲酸中金属含量不确定度的评估

Evaluation of measurement uncertainty for determination of metal in purified terephthalic acid by flame atomic absorption spectrophotometry

以铁元素为例评价了火焰原子吸收分光光度法测定精对苯二甲酸中金属含量的不确定度。建立数学模型,对各不确定度分量进行了分析和评定,对各不确定度分量进行合成,得到铁含量的不确定度。结果表明:测量过程重复性和标准曲线拟合引入的不确定度是整个测量过程不确定度主要来源,通过评定得出铁元素的相对扩展不确定度为0.007×10^(-6)(k=2)。

In this paper,the iron element was taken as an example to evaluate the uncertainty of metal content in purified terephthalic acid by using flame atomic absorption spectrophotometry. Amathematic model was established by analyzing the uncertainty sources from different parts. The uncertainty of iron content was calculated by synthesis of each uncertainty component. The results show that the measurement repeatability and the fitted linear equation for the standard curve is the main source of uncertainties,and the uncertainty of the expansion of the iron element was 0. 007 × 10^-6（ k = 2）.