气相分子吸收光谱法测定水中硝酸盐氮浓度不确定度评定

Uncertainty evaluation of determination of nitrate nitrogen in the water by the gas-phase molecular absorption spectrometry

采用气相分子吸收光谱仪法测定水样中硝酸盐氮的浓度,对其不确定度来源进行分析、评估,结果表明,当水样浓度为2.05mg/L时,考虑测定过程的标准曲线拟合、标准溶液的配制、样品测量重复性等因素对测定结果造成影响,测得硝酸盐氮的相对合成标准不确定度为0.12mg/L,其中由标准曲线拟合过程引起的测量不确定度和样品测量重复性引入的不确定度相当,是最主要的不确定分量。

The concentration of Nitrate Nitrogen in the solution is measured by the gasphase molecular absorption spectrometry in this paper.And the major sources of measurement uncertainty were discussed and evaluated.Uncertainty components such as standard curve fitting,preparation of standard solutions,measurement repeatability were analyzed and synthesized.The results show that the total combined standard uncertainty was 0.12 mg/L when the concentration of Nitrate Nitrogen is 2.05mg/L.And the standard curve fitting and measurement repeatability have the same contribution,which are the main source of uncertainty among these components.