葡萄酒中总酸测量的不确定度评定

目的评定酸碱滴定法测定葡萄酒中总酸的不确定度。方法依据JJF1059.1-2012《测量不确定度评定与表示》,分析总酸含量测定过程中的不确定度来源,通过建立数学模型量化不确定度分量,计算合成不确定度及扩展不确定度。结果该方法检测葡萄酒中总酸的合成不确定度为0.063 g/L,扩展不确定度为0.13g/L。本实验测定的葡萄酒中总酸含量结果为(5.53±0.13)g/L(k=2,置信区间P为95%)。结论本方法的不确定度主要由重复性、标准溶液滴定体积、取样体积等引入。

Uncertainty evaluation of determination of total acid in wine

Objective To evaluate the uncertainty in determination of total acid in wine by acid base titration. Methods According to the JJF 1059.12-2012 Evaluation and expression of uncertainty in measurement, the sources of uncertainty in determination of total acid were analyzed. Furthermore, the combined uncertainty and expanded uncertainty were calculated based on the established mathematic models. Results The combined uncertainty of the whole experiment process was 0.063 g/L, and the expanded uncertainty was 0.13 g/L. The content of total acid in wine was (5.53±0.13) g/L (k=2, P=95%). Conclusion The uncertainty of this method is mainly caused by repeatability, titration volume of standard solution and sampling volume.