容量法测定卤水中碘含量的不确定度评定

Uncertainty evaluation in determination of iodine content in brine by volumetric method

为提高容量法测定卤水中碘含量的准确度,对饱和溴水法测定碘含量做了评定。从碘酸钾标准溶液配制、硫代硫酸钠标准溶液标定、卤水样品测定3个方面归纳不确定度来源。通过建立数学模型,给出了测定卤水中碘含量的各不确定度分量的详细评定过程,由各不确定度分量求得了碘含量的合成标准不确定度及扩展不确定度,当置信水平为95%时,得出卤水中碘含量的测定不确定度为17.52±0.116 mg/L。

In order to improve the accuracy of the volumetric method for the determination of iodine content in brine,the determination of iodine content by saturated bromine water method was evaluated.The source of uncertainty was summarized from three aspects,such as the preparation of potassium iodate standard solution,calibration of Na2 S2 O3 standard solution and brine sample determination.The detailed evaluation process of uncertainty components in measurement of iodine content in brine was given by establishing mathematics model.Synthesis standard uncertainty and expanded uncertainty of iodine content were obtained by the uncertainty components.The uncertainty of measurement of iodine content in brine was 17.52±0.116 mg/L in the level of 95%confidence level.