石墨炉原子吸收分光光度法测定水样中铬的不确定度

[目的]通过对影响测定结果的不确定度因素的分析和量化,评价石墨炉原子吸收光谱法测定水样中铬的不确定度。[方法]调节仪器最佳测定条件,测定铬标准工作溶液系列并依据工作软件自动建立工作曲线和数学模型;连续测量10次水样,根据标准曲线获得未知样品铬浓度;分析石墨炉原子吸收分光光度法测定水样中铬的误差性质和来源,确定不确定度的主要因素,计算水样中铬的测量不确定度。[结果]扩展不确定度U95=0.016mg/L（Veff=20）。[结论]根据分析仪器的测定数据输出方式建立数学模型,进行不确定度评定,方法直观简明,与实际工作相符合。

Uncertainty on the Determination of Chromium in Water Samples with Graphite Oven Atomic Absorption Spectrophotometry

[Objectives] To standardize and rationalize the uncertainty analyzing procedure for the determination of chromium in water samples with Graphite Oven atomic absorption spectrophotometry.[Methods] The calibration curve of the standard series at the best working conditions of the instrument was established,the water sample was measured 6 times consecutively to determine the chromium concentration of the unknown samples.Mathematical models were established with the aid of advanced software.The errors in the measurement were analyzed to confirm the main factors for the uncertainty.[Results] The expanded uncertainty was U95=0.016 mg/ L（Veff=20）.[Conclusions] Uncertainty analysis based on the mathematical models computed from the measured data output was proved to be simple and practical.