电位返滴定法测定玉叶金花中总有机酸的含量

Determination of total organic acids from Mussaenda Pubescens Ait.f. by potentiometric back titration

目的建立玉叶金花药材中总有机酸含量测定的方法。方法采用电位返滴定法,以水杨酸为对照品,测定样品中总有机酸的含量。结果测定了广东省10个不同产地及广州地区不同月份采集的玉叶金花药材,总有机酸质量分数在2.10%～8.65%范围内(RSD值为0.02%～0.17%,n=5)。结论该方法操作简便、重复性好、准确度高,可作为玉叶金花药材总有机酸含量测定的方法。

Objective To establish a determination method for the total organic acids in Mussaenda Pubescens Ait. f.. Methods Salicylic acid was employed as reference to determine the total organic acids by potentiometric back titration. Results Ten samples of different orgins and the sample of each month were assayed, and the free total organic acids in the extracts of Mussaenda Pubescens Air. f. were between 2. 10% - 8.65 % （ RSD = 0. 02% - 0. 17 % , n = 5 ）. Conclusion This method is simple, accurate and may be used to determine the total organic acid in Mussaenda Pubescens Ait. f..