自动电位滴定法测定水中总硬度的不确定度评定

Evaluation of Uncertainty of Total Hardness in Water with Automatic Potentiometric Titration

依据测量不确定度的评定原理和方法,通过自动电位滴定法测定水中总硬度的实例,分析了测量重复性、取样、标准溶液浓度、标准溶液配制过程、滴定管、摩尔质量等因素对总硬度测量不确度的影响,确定不确定度数学模型,及不确定度报告的书写形式。在总硬度为103mg/L的水样测定中,测得其合成标准不确定度为0.6168mg/L,扩展不确定度为1.3mg/L。

Evaluation of measurement uncertainty based on principles and methods,with automatic potentiometric titration,and instances of total hardness in water,the measurement repeatability,sample,standard solution concentration,standard solution preparation process,Burette,molar mass and other factors on the overall degree of hardness measurement of the impact of inaccurate were analyzed,the uncertainty of mathematical model was determined,as well as the uncertainty of the report written form.The total hardness of 103mg/L of water sample,the combined standard uncertainty of 0.6168mg/L was obtained,and the expanded uncertainty of 1.3mg/L.