火焰原子吸收法测定水中镁元素含量的不确定度评定

Evaluation on Uncertainty of Determining Magnesium in Drinking Water by Flame Atomic Absorption Spectrophotometry

摘要:
目的通过火焰原子吸收光谱法测定饮用水中镁的含量, 分析测试过程中不确定度的来源, 并对各不确定度的分量进行评定。
方法根据测量不确定度的评定理论, 通过对实际水样的测定, 分析和计算测定过程中不确定的来源。
结果分析结果显示不确定度主要来源于标准溶液测定(包括标准储备液的不确定度, 标准应用液的稀释, 标准系列的配置, 标准曲线的拟合)、样品溶液的稀释和重复测量样品等。
结论计算出各种不确定度分量并将其合成, 以此计算出水中镁的测试结果为:C_Mg=(0.395±0.012) mg/L, k=2(置信水平约为95%)。

Abstract:
Objectives According to the content of magnesium in drinking water with flame atomic absorption spectrophotometry, analyze and assess factors influencing the uncertainty in testing process.
Methods Based on the theory of evaluating uncertainty, the sources of uncertainty in whole testing process were analyzed and calculated.
Results The main sources of uncertainty were from developing standard solution (including the preparation of standard stock solution, and the dilution of standard solution) and standard curve fitting, the degree of sample dilution and preparation and repeated sample measurements.
Conclusions The test results of magnesium in drinking water were C_Mg=(0.395±0.012) mg/L, k=2 (confidence level≈95%).