Optimisation of separation selectivity in capillary zone electrophoresis of inorganic anions using binary cationic surfactant mixtures

Mixtures of different cationic surfactants such as dodecyltrimethylammonium bromide and tetrade-cyltrimethylammonium bromide can be used as carrier electrolyte additives in order to manipulate separation selectivity and resolution of inorganic anions in capillary zone electrophoresis. The migration order is dependent on both the total surfactant concentration and the ratio of the two surfactants. The optimisation of separation selectivity is demonstrated for a nine-anion standard mixture as well as for complex matrices such as Bayer liquor.