Separation and simultaneous determination of quinolone antibiotics by capillary zone electrophoresis

The potential of capillary zone electrophoresis has been investigated for t he separation and quantitative determination of some quinolone antibiotics. The influence of different conditions, such as the nature and concentratio n of the electrophoretic electrolyte, on migration time, peak symmetry, eff iciency and resolution was studied. A buffer consisting of 100 mM HEPES adj usted to pH 8.5 containing 10 % (v/v) acetonitrile was found to furnish a v ery efficient and stable electrophoretic system for the separation of enoxa cin, ciprofloxacin, ofloxacin, oxolinic acid, nalidixic acid and pipemedic acid. A linear relationship between concentration and peak area for each co mpound was obtained in the concentration range 0.25-40 mu g mL(-1); detecti on limits were approximately 0.25 ng mL(-1). It was demonstrated that the m ethod can be used for the simultaneous determination of these six antibioti cs in serum and urine samples.