AN HPLC WITH PHOTODIODE ARRAY DETECTION METHOD FOR SIMULTANEOUS DETERMINATION OF ENROFLOXACIN AND ITS ACTIVE METABOLITE, CIPROFLOXACIN, IN CHICKEN MEAT

A reverse-phase liquid chromatography (LC) method was developed for the simultaneous estimation of enrofloxacin and its active metabolite ciprofloxacin residues in chicken meat. These two fluoroquinolones were extracted from homogenized tissues with phosphate buffer under acidic conditions, followed by acetonitrile. The isocratic LC analysis was performed on Phenonmenax, C18 RP column (250 × 4.6 mm, 5 μ) using a mobile phase composed of 0.025M potassium phosphate solution (pH 3.25) and acetonitrile in the ratio of 75:25 (v/v), at a flow rate of 0.500 ml/ min. Quantitation of enrofloxacin and its metabolite were performed using a PDA detector set at the wavelength of 277 nm. The temperature of the column was 30⁰C, and the total run time was 20 min for the analysis of both drugs. The retention time was found to be 10 min for ciprofloxacin and 13 min for enrofloxacin. The r² values for linearity studies were greater than 0.98, and the accuracy (% recovery) was greater than 88% for both the drugs. The linearity was observed in the range of 10 to 1000 ng/ml with correlation coefficient, r² = 0.9895 and 0.9801 for enrofloxacin and ciprofloxacin, respectively. The average recovery of enrofloxacin and ciprofloxacin from fortified control tissue samples was in the range of 88 to 94%. The limits of quantification for enrofloxacin and ciprofloxacin were 30 and 35 µg/kg in chicken tissues under photodiode array detection. The linearity, recovery, and detection limits of the method were evaluated from spiked tissue samples and results were found good and within range.