HPLC Determination of Several Residual Veterinary Medicines in Chicken

A HPLC method for the determination of 4 residual quinolone antimicrobials (ofloxacin,norfloxacin,ciprofloxacin and enrofloxacin) in chicken was proposed.The residual medicines in chicken sample were extracted with acetonitrile,protein and fatty substances in the acetonitrile extract were removed by liquid-liquid partition with n-hexane.The acetonitrile layer was collected and evaporated with a rotary evaporator.Finally the residue was taken up with acetonitrile-water (6+4) mixture and used for HPLC determination with fluorescence detector and external standard calibration curve method.Linear relationship between chromatographic peaks and mass concentrations of all the 4 antimicrobials were kept in the range of 0.05-1.2 mg·L-1,with correlation coefficients from 0.999 7 to 0.999 9.Average values of recovery tested in the concentration range of 0.05-1.00 mg·kg-1 were in range from 78.3% to 101.8%,with RSD′s (n=7) from 3.89% to 12.43%.Detection limits of this method were found to be 0.003 7 mg·kg-1 (for ofloxacin,norfloxacin),0.003 5 mg·kg-1 (for ciprofloxacin) and 0.002 2 mg·kg-1 (for enrofloxacin).