直接碘量法测定葡萄酒中总二氧化硫含量的不确定度评定

摘要

According to Evaluation of the Uncertainty in Chemical Analysis Measurement, the uncertainty of total sulfur dioxide content in grape wine by direct iodimetric analysis was analysed, and the factors influencing the determination results were investigated. The results showed that the uncertainty induced by the molar mass of potassium dichromate and sulfur dioxide had no significant effects on determination results, the un- certainty induced by repeatability had greatest effects, and the uncertainty induced by the use level of iodine standard volume had significant effects. Total sulfur dioxide content in grape wine was finally summed up as 136 mg/L±1 mg/L;k=2.%根据《化学分析中不确定度的评估指南》，通过对直接碘量法测定葡萄酒中总二氧化硫含量的不确定度进行分析。结果表明，由重铬酸钾及二氧化硫摩尔质量引起的不确定度较小，对结果无显著影响；由重复性引起的不确定度最大；测定样品时，碘标准溶液体积的用量引入的不确定度也较大；测定分析得葡萄酒中总二氧化硫含量的最后结果为136mg／L＋lmg／L；k=2，