Abstract: A micellar capillary electrophoresis(MCE) method based on on-line sweeping technique was developed for a determination of trace quinolones, ciprofloxacin ofloxacin and enrofloxacin in pork tissue. The pork tissue samples were deproteinized with trichloroacetic acid and in the running buffer of 20 mmol/L Na₂B₄O₇+80 mmol/L sodium dodecyl sulfate(SDS), pH=9.6, the ciprofloxacin, ofloxacin and enrofloxacin in the sample were successfully separated and detected within 200 s, in a non-coating fused-silica capillary column(48.5 cm×75 μm i.d., effective length 40 cm) at separation voltage of 18 kV, and the injection pressure of 15×10² Pa, with UV detection at 278 nm. The detection limits of ciprofloxacin, ofloxacin and enrofloxacin were 0.007, 0.016 and 0.020 mg/L, and RSD were 2.0%, 2.4% and 2.6%, respectively. This method allows of up to 600-fold accumulation concentration of ciprofloxacin and can be used to separate and detect the residuals of trace medicines in animal food.

Key words: Micellar capillary electrophoresis(MCE), On-line sweeping technique, Trace, Quinolones, Pork tissue