Determination of quinolones in animal tissues and eggs by high-performance liquid chromatography with photodiode-array detection.

A rapid, specific reversed-phase HPLC method is described, with solid-phase extraction, for assaying five quinolones (ciprofloxacin, difloxacin, enrofloxacin, norfloxacin and marbofloxacin) with confirmative diode-array detection in samples of bovine kidney, muscle and eggs. The least efficient extraction was marbofloxacin from kidney tissue (64%). The lower detection limit for each quinolone was: enrofloxacin and ciprofloxacin, 1 ng; norfloxacin and difloxacin, 2 ng; marbofloxacin, 4 ng injected. The intra-day relative standard deviations were lower than 7.9% and lower than 8.6% for inter-day assays. These results indicate that the developed method had an acceptable precision.