电位滴定法测定槟榔中游离碱度的不确定度评定

目的对电位滴定法测定槟榔中游离碱度含量进行不确定度评定。方法建立影响槟榔中游离碱度测量结果的数学模型,并对电位滴定法测量槟榔中游离碱度的测量结果进行不确定度评定。结果样品槟榔中游离碱度含量为6.5 mg/g时,测定结果的合成标准不确定度为0.065 mg/g,扩展不确定度为0.13 mg/g。结论DB43/132-2004《食用槟榔》标准方法测定槟榔中游离碱度不确定度的最主要来源是盐酸标准滴定溶液体积引入的不确定度,因此在实验过程中应该严格控制滴定终点,确保实验结果准确可靠。

Uncertainty evaluation for determination of free alkalinity in edible betelnut by potentiometric titration

Objective To evaluate the uncertainty of determination of free alkalinity in edible betelnut by potentiometric titration. Methods A mathematical model for affecting factors of the results of free alkalinity in edible betelnut was established, and the uncertainty evaluation of free alkalinity in edible betelnut by potentiometric titration was estimated. Results The results showed that the combined standard uncertainty was 0.065 mg/g and the expanded uncertainty was 0.13 mg/g when the free alkalinity was 6.5 mg/g in the edible betelnut sample. Conclusion The main source of the standard method for determination of free alkalinity in edible betelnut by DB43/132-2004 Edible betelnut is the uncertainty of the volume of hydrochloric acid standard titrition solution, so we should strictly control the titration end in the experimental process so as to ensure accurate and reliable results.