食盐中碘含量的测量不确定度

根据《测量不确定度评定与表示》（JJF 1059-1999），对食盐中碘含量的测量不确定度进行评定。建立数学模型，对测量不确定度分量进行分析和量化。当食盐中碘含量为45．86mg／kg时，合成标准不确定度为0．21mg／kg，扩展不确定度为0．42mg／kg。食盐中碘含量的测量不确定度主要来源于硫代硫酸钠标准溶液的浓度和滴定消耗的体积。

EVALUATION OF THE UNCERTAINTY OF MEASUREMENT FOR THE DETERMINATION OF IODIN CONTENT IN TABLE SALT

The uncertainty of measurement for the determination of the iodin content in table salt was evaluated according to Evaluation and Expression of Uncertainty in Measurement(JJF 1059-1999).The mathematics model was established,and the components of uncertanity in measurement were analysed and calculated.When the result of iodin content in table salt was 45.86 mg/kg,the combined uncertainty was 0.21 mg/kg,and the expanded uncertainty was 1.6 mg/kg.The major source of uncertainty were the concentration of Na_2S_2O_(3) standard titrion solution and the lost volume in titrion.