离子选择电极法测定水中氟化物的不确定度评定

Uncertainty Evaluation for the Determination of Fluoride in Water by Ion Selective Electrode Method

目的:采用离子选择电极法测定生活饮用水中氟化物的含量,评定测定过程中的不确定度分量。方法:依据标准《测量不确定度评定与表示》(JJF 1059.1—2012)和《化学分析中不确定度的评估指南》(CNAS-GL006:2019),分析不确定度来源,建立数学模型,对测定过程中的各不确定度分量进行分析和计算,综合评估氟化物含量的不确定度。结果:当生活饮用水中氟化物的含量为0.915 mg·L^(-1)时,其扩展不确定度为0.038 mg·L^(-1)(k=2),测定结果可表示为(0.915±0.038)mg·L^(-1)(k=2)。结论:影响检测结果不确定度的因素主要是标准系列溶液的配制,在实验中可以通过严格控制标准系列溶液的配制过程提高检测结果的准确性。

Objective:The content of fluoride in drinking water was determined by ion selective electrode method,and the uncertainty which might be introduced in the process of determination was evaluated.Method:According to JJF 1059.1—2012,CNAS-GL006:2019,the source of uncertainty was identified and the measurement model was established,the component of uncertainty is analyzed and calculated,and the uncertainty of fluoride content was evaluated comprehensively.Result:When fluoride content in drinking water was 0.915 mg·L^(-1),the expanded uncertainty was 0.038 mg·L^(-1)(k=2),and the measurement result was expressed as(0.915±0.038)mg·L^(-1)(k=2).Conclusion:The main factor that affects the uncertainty of the test results was the preparation of the standard series of solutions.In the experiment,the accuracy of the test results can be improved by strictly controlling the preparation process of the standard series of solutions.