伏特加碱度测定的不确定度分析

Analysis of Uncertainty in the Determination of Alkalinity of Vodka

采用滴定法对于伏特加的碱度进行试验分析。以盐酸为滴定剂,以甲基红为指示剂,通过盐酸标准滴定溶液消耗量去计算试样的碱度。通过数学模型的建立,对于试验中的各个影响因素进行了分析评定,主要分析了容量瓶的容量允差、标准滴定溶液浓度、滴定操作过程以及重复性测定4个要素对于试验结果不确定度的贡献,其中贡献最大的两个要素为容量瓶的容量允差和滴定操作过程。通过针对各个不确定度的分量进行量化计算和合成,得出此试验用的伏特加碱度的不确定度表示为:2.0mL±0.054 mL。

The alkalinity of vodka was detected and analyzed by titration.Using hydrochloric acid as the titrant and methyl red as the indicator,the alkalinity of the sample was calculated by the consumption of the titrant.Through establishing the mathematical model,the various influencing factors in the experiment were analyzed and evaluated,and the uncertainty contributions of the volume tolerance,the titrant concentration,the titration operation and the repeatability determination were analyzed.The two factors that contributed the most were the volume tolerance of the volumetric flask and the titration operation process.Through quantitative calculation and synthesis of each uncertainty component,the uncertainty of the alkalinity of the vodka sample used in this test was 2.0 mL±0.054 mL.