pH indicator titration: A novel fast pKa determination method

被引：8
作者：
Kong, Xiaole
Zhou, Tao
Liu, Zudong
Hider, Robert C.
机构：
[1] Kings Coll London, Div Pharmaceut Sci, London SE1 9NH, England
[2] Kings Coll London, Ctr Nat Med Res, London SE1 9NH, England
来源：
JOURNAL OF PHARMACEUTICAL SCIENCES | 2007年 / 96卷 / 10期
关键词：
fast determination; ionization constants pKa values; protonation constants; spectrophotometic titration;
D O I：
10.1002/jps.20959
中图分类号：
R914 [药物化学];
学科分类号：
100701 ;
摘要：
This study describes a fast spectrophotometic titration method for apparent ionization constant (pKa.) determination. In this method, a Universal pH indicator is utilized instead of the conventional pH electrode. An autoburette is set to add HCl at a constant rate to a vigorously stirred 1 cm UV cuvette which contains sample and indicator solution. A spectrophotometer continuously records the spectra. Acquired spectral data are processed by calculating the pH from the indicator spectra in the visible region and extracting sample spectra from the UV region. Five compounds possessing pKa values in the range 2-10 were investigated. These results differed from measurements by conventional spectrophotometric titration by +/- 0.05 to +/- 0.10 log unit. (c) 2007 Wiley-Liss, Inc.
引用
收藏
页码：2777 / 2783
页数：7
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