气相分子吸收光谱法测定水中亚硝酸盐氮浓度不确定度评定

Evaluation of Uncertainty Measurement of Nitrite-Nitrogen in the Solution by the Gas-phase Molecular Absorption Spectrometry

采用气相分子吸收光谱仪法测定水样中亚硝酸盐氮的浓度,对其不确定度来源进行分析、评估。结果表明,当水样质量浓度为1.02 mg/L时,考虑测定过程的标准溶液的配制、曲线拟合、仪器测量重复性等因素对测定结果造成影响,测得亚硝酸盐氮的相对合成标准不确定度为0.03 mg/L,其中最主要的分量是由亚硝酸盐氮标准溶液引起的测量不确定度。

The nitrite-nitrogen concentration in the water is measured by the gas-phase molecular absorption spectrometry, and the impacts of major sources of uncertainty measurement are researched. The result shows that when nitrite-nitrogen concentration in the solution is 1. 02 mg/ L, considering the effects of preparation of standard solution, curve coupling and the repeatable instrument measurement on the measured results, the expanded standard uncertainty is 0. 03 mg/ L and the standard nitrite-nitrogen solution is the main source of uncertainty among these factors.