Electrophoretic behaviour of zwitterionic compounds in capillary electrophoresis: Prediction of mobility of several quinolones Original Research Article

A model of electrophoretic behaviour is studied in order to optimize the separation of zwitterionic substances by capillary electrophoresis. The equations derived allow the electrophoretic mobilities of substances at each pH to be predicted and, consequently the resolution between pairs of substances. The model considers the effect of ionic strength and can be applied to zwitterionic substances with very close pKa values. The model is tested to obtain the optimum pH values for the separation of a series of eight quinolones on the basis of a few initial experiments.