Optimization of the separation of beta-agonists by capillary electrophoresis on untreated and C18 bonded silica capillaries.

The conditions of the separation of ten beta-agonists by capillary zone electrophoresis were studied. Several buffers were tested at different ionic strengths and different pH values. The experiments were carried out on two different supports, i.e. an untreated fused-silica capillary and a C18 covalently bonded silica capillary. The results showed that the optimum pH value was the same for the two capillaries. Separation efficiencies were slightly better for the fused-silica capillary whereas better selectivity and repeatability were obtained with the C18 bonded capillary, under optimal conditions.