Abstract: Sitafloxacin epimers were separated by capillary zone electrophoresis using γ-cyclodextrin(γ-CD) and D-phenylalanine (D-Phe) as chiral selector．The effects of the concentrations of γ-CD, D-Phe, Cu2+ and pH of buffer were investigated．An uncoated fused-silica capillary of 50 μm i.d. and 60 cm (effective length 52.5 cm) was used．The capillary temperature was maintained at 25 ℃．Samples were injected under a pressure of 7 kPa for 5 s and separated at 15 kV．A baseline separation of sitafloxacin epimers was achieved with a background electrolyte of 10 mmol/L KH2PO4-K2HPO4 (pH 4.5), 10 mmol/L CuSO4, 20 mmol/L γ-CD and 10 mmol/L D-Phe．The linear range for sitafloxacin was 32-400 mg/L (0.996)．The relative standard deviations (RSDs) of migration time and peak area were less than 1.9% and 3.8% respectively．This method can be applied in qualitative and quantitative analysis for sitafloxacin epimers.

Key words: epimers , sitafloxacin, capillary electrophoresis (CE)