水中总硬度测定的不确定度评定

Assessment of uncertainty about the determination of water hardness

目的探讨水中总硬度测定的不确定度评价方法。方法采用Na2EDTA滴定法测定某水样的总硬度,并对测定结果的质量进行不确定度的评定和说明。结果按数据模型计算该水样的总硬度为167.0mg/L。相对不确定度为0.00670,扩展不确定度为2.2mg/L,不确定度的表达为(137.0±2.2)mg/L;k=2。结论该方法对评价水中总硬度测定的容量分析法的不确定度有一定的参考价值。

Objective To Investigate the method of water assessment of uncertainty about the determination of water hardness.Methods Determination by Na2EDTA total hardness of a water sample,and the quality determination results and description of Uncertainty.Results According to the data model,the total water hardness was 167.0mg / L.The relative uncertainty was 0.00670,the expanded uncertainty was 2.2 mg / L,the expression of uncertainty was（137.0 ± 2.2） mg / L;k = 2.Conclusions This method for evaluating the capacity of the water hardness test uncertainty analysis has some reference value.