Determination of ionization constants of heterocyclic aromatic amines using capillary zone electrophoresis

Capillary zone electrophoresis (CZE) is a very convenient technique for the determination of ionization constants. The technique is rapid, precise, uses small quantities of solute, and the exact concentration of the compound is not needed. This work represents the first report on the ionization constants of eight heterocyclic aromatic amines: 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-9H-pyrido[2,3-b]indole, 3-amino-1-methyl-5H-pyrido[4, 3-b]indole acetate, 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline, 2-amino-3,3,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline and 9-H-pyrido[4,3-b]indole. The ionization constants determined using CZE were confirmed with independent determinations by ultraviolet spectrometry. (C) 1999 Elsevier Science B.V. All rights reserved.