SEPARATION OF PHENYLENEDIAMINE, PHENOL AND AMINOPHENOL DERIVATIVES BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY - COMPARISON OF THE ROLE OF ANIONIC AND CATIONIC SURFACTANTS

mixture of phenylenediamine, aminophenol and phenol derivatives was studied with capillary zone electrophoresis (CZE) at different pi-Is. The use of acidic dr alkaline pH did not give separations with a good resolution. Next, separation was performed using micellar electrokinetic capillary chromatography (MEKC), first with the anionic surfactant sodium dodecyl sulfate (SDS) and second with the cationic surfactant cetyl trimethylammoniumchloride (CTACl). In both cases, a study of pH, surfactant concentration and ionic strength of the electrolyte as function of the capacity factor allowed for the determination of the optimum conditions. Since separation was obtained with both surfactants, we studied the distribution coefficient to determine the affinities of the solutes for the aqueous medium and the different surfactants.