离子色谱法测定饮用矿泉水中硝酸盐的不确定性分析

目的了解用离子色谱法测定饮用矿泉水中硝酸盐离子的不确定度评定。方法利用离子色谱仪对饮用矿泉水中硝酸盐离子进行测定实践,建立测量数学模式,分析影响因素主要有:①来自重复测量引入的A类不确定度;②来自工作曲线的不确定度;③来自标准溶液的不确定度。结果利用离子色谱法测定饮用矿泉水中硝酸盐离子浓度为0.800 mg/L时,其扩展不确定度为U=0.086 mg/L,k=2。扩展相对不确定度为Urel=10.8%。结论测定过程中,不确定度的主要来源是来自工作曲线的标准不确定度。

Analysis of Uncertainty in Determination of Nitrate in Drinking Mineral Water by Ion Chromatography

[Objective]To understand the uncertainty evaluation of nitrate determination in drinking mineral water by ion chromatography.[Methods]Ion chromatography was used to drink mineral water on the determination of nitrate ion in practice.The mathematical model was established for influencing factors analysis： ① the class A uncertainty induced by repeated measurement;② the uncertainty from the working curve;③ the uncertainty from the standard solution.[Results]When using ion chromatography to detect nitrate ion concentration in drinking mineral water as 0.800 mg/L,the expanded uncertainty was U=0.086 mg/L,k=2,and expanded relative uncertainty was Urel=10.8%.[Conclusion]In the determination process,the main source of uncertainty comes from standard uncertainty of working curve.