Determination of pKa values of benzimidazole derivatives from mobility obtained by capillary electrophoresis.

Dissociation constants of benzimidazole derivatives have been determined using capillary zone electrophoresis (CZE). Since CZE is a separation method, high purity and known concentration for the samples is not necessary because only mobilities are measured. The precision of pK(a) measurements of seven compounds is useful to observe pK(a) shifts induced by chemical variations. Some of them were compared to potentiometry and spectroscopy experiments. Good correlated pK(a) values are observed between the three analytical techniques.