Departament de Química Analítica and Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, E-08028 Barcelona, Spain.
J Chromatogr A. 2013 Mar 1;1279:108-16. doi: 10.1016/j.chroma.2013.01.018. Epub 2013 Jan 10.
The IS-CE method is developed for pK(a) determination of polyprotic compounds. In this method, the internal standard (IS) and the polyprotic test compound are injected into the capillary electrophoresis (CE) system in buffers with appropriate pH. The pH of the buffers is not externally measured, but determined inside the capillary from the mobilities of the internal standards. Then the pK(a) values of the polyprotic compounds are obtained by fitting its mobilities to the in situ pH values. The method is faster than the classical CE method (a diprotic compound can be done in less than 15 min), and also than other methods like potentiometric and spectrophotometric titrations. The method has been successfully applied to 20 polyprotic test compounds of different chemical nature, including compounds with extreme or very close pK(a) values.
IS-CE 法用于测定多质子化合物的 pKa 值。在该方法中，内标（IS）和多质子测试化合物被注入到具有适当 pH 值的缓冲液中的毛细管电泳（CE）系统中。缓冲液的 pH 值不是外部测量的，而是从内标物的迁移率在毛细管内确定的。然后，通过将多质子化合物的迁移率拟合到原位 pH 值来获得 pKa 值。该方法比经典的 CE 方法（可在 15 分钟内完成二质子化合物的测定）以及其他方法（如电位滴定法和分光光度滴定法）更快。该方法已成功应用于 20 种不同化学性质的多质子测试化合物，包括具有极端或非常接近 pKa 值的化合物。
