Abstract:

A study on florfenicol （FF） and florfenicol amine （FFA） residue depletion was conducted in chicken muscle. FF and FFA were extracted from chicken muscle with acetone and dichloromethane. The extract solution was degreased in nhexane saturated with acetonitrile, dried in nitrogen evaporator and residues were dissolved in mobile phase. FF and FFA were determinated by high performance liquid chromatography （HPLC） with fluorescence detector. The mobile phase was acetonitrilemonosodium phosphate solution（0.01 mol·L-1, containing 0.005 mol·L-1 SDS and 0.1% triethylamine）（35:65 by volume）, the flow rate was 1.0 mL ·min-1. The fluorescence detection was with an excitation wavelength of 225 nm and an emission wavelength of 285 nm. Result were as follows: The limits of detection（LODs）of FF and FFA were 1.5 μg·kg-1（S/N=3） and 0.5 μg·kg-1（S/N=3）, respectively. The limits of quantitation （LOQs）were 5 μg·kg-1（S/N=10）and 2 μg·kg-1（S/N=10）, respectively. After the chickens orally administered successively FF capsules of 25.0 mg·kg-1, 50.0 mg·kg-1 and 100.0 mg·kg-1 of body weight one time every day for 5 days, respectively, at the first withdrawal day, the maximum residues of FF and FFA were detected. The residues were rising with the dosage and reducing with the withdrawal time. At the 7th withdrawal day, the total residues of FF and FFA were all lower than the MRLs （100 μg·kg-1）; and all lower than the lowest LOD at 11th withdrawal day. The residues and total residues of FF and FFA in chicken muscle were all positively correlated with FF orally administered doses.