Quick and Sensitive Determination of Fluoroquinolones by Capillary Electrophoresis–Potential Gradient Detection

A rapid, capillary electrophoresis–potential gradient detection method was developed for determining three fluoroquinolones: rufloxacin, enoxacin, and moxifloxacin. The fluoroquinolones were baseline separated within 3.5 min with background electrolyte composed of 50 mM acetic acid and 6 mM potassium hydroxide at pH 3.7. For the first time, electrokinetic injection was applied in capillary electrophoretic separation of fluoroquinolones, and an average of ca. 10-fold improvement in detection limits was observed. The method was applied to a fortified chicken tissue sample with detection limits (S/N = 3) of 22–24 ng g−1, suggesting the potential of the method for determining fluoroquinolone residues in real samples.