Simultaneous determination of benofloxacin, danofloxacin, enrofloxacin and ofloxacin in chicken tissue by high-performance liquid chromatography.

A simple, rapid and reliable high-performance liquid chromatographic (HPLC) method for the simultaneous determination of residual fluoroquinolones (benofloxacin, danofloxacin, enrofloxacin and ofloxacin) in chicken has been developed. The drugs were extracted with 0.2% metaphosphoric acid-acetonitrile (7:3, v/v), followed by a Bond Elut C18 clean-up procedure. The HPLC separation was carried out on a Wakosil II 5C18-HG column (150 x 4.6 mm I.D.) with 0.05 M phosphate buffer (pH 2.4)-acetonitrile (80:20, v/v) containing 2.5 mM 1-heptanesulfonic acid as the mobile phase. A fluorescence detector was used at an excitation wavelength of 295 nm and an emission wavelength of 455 nm. The calibration graphs were linear from 0.1 to 10 ng for danofloxacin and from 1 to 100 ng for benofloxacin, enrofloxacin and ofloxacin. The recoveries of the drugs from tissues fortified at a level of 0.2 microgram/g were 81.1-89.6%, and the detection limits were 0.01 microgram/g for ofloxacin, danofloxacin and enrofloxacin and 0.02 microgram/kg for benofloxacin. The time needed per sample was less than 60 min.