SIMULTANEOUS DETERMINATION OF ENROFLOXACI N AND ITS PRIMARY METABOLITE CIPROFLOXACIN IN MEAT AND FISH BY HPLC

A simple, reliable and sensitive method for the simultaneous determina tion of residual enrofloxacin and its primary metabolite, ciprofloxaci n, in meat and fish by HPLC has been developed. The drugs were extract ed with 0.3% metaphosphoric acid-acetonitrile (6:4), and the extracts were cleaned up on an Oasis HLB cartridge. The HPLC separation was car ried out on a TSK-GEL Super ODS column(100 x 4.6 mm i.d.) with 0.05 mo l/L phosphate buffer (pH 2.5)-acetonitrile (70 : 30) containing 1.0 mm ol/L sodium dodecyl sulfate (SDS) as the mobile phase at a flow rate o f 0.5 mL/min. A fluorescence detector was operated at an excitation wa velength of 278 nm and an emission wavelength of 445 nm. The calibrati on graphs were rectilinear from 0.5 to 20 ng for both drugs. The recov eries of the drugs from tissues fortified at the level of 0.2 mu g/g w ere greater than 80%, and the detection limits were 0.005 mu g/g for b oth drugs. The influence of baking on enrofloxacin and ciprofloxacin r esidues in flatfish was investigated. Both drugs showed excellent ther mal stability.