Residues of Ciprofloxacin in Eggs of Laying Hens

A high-performance liquid chromatographic method(HPLC) was reported for the quantitative determination of residues of ciprofloxacin in eggs of laying hen.Ciprofloxacin was extracted from eggs with acetonitrile solution.The extract solution was dried in vacuum condition(45℃) and residues were dissolved in mobile phase.Ciprofloxacin was separated on a Symmetry C_ 18 Column(5 μm,3.9 mm×150 mm) by 0.015 mol/L tetrabutyl ammonium bromide/acetonitrile(94/6) and determinated at λ_ EX 280 nm,λ_ EM 455 nm by fluorescence detector.Recoveries of ciprofloxacin added to blank eggs at levels of 0.05,0.50,1.00 mg/kg were(82.2±6.8)%,(84.5±5.9)% and (87.9±4.7)%,respectively.This method permitted the minimum detection limit of ciprofloxacin residues in eggs at 0.01 mg/kg.After the laying hens orally administered successively ciprofloxacin hydrochloride solution of 10 mg/kg and 20 mg/kg of body weight one time every day for 5 days,respectively,residues of ciprofloxacin in eggs were eliminated slowly.Residues of ciprofloxacin in eggs were lower than 0.03 mg/kg at 8 th-9 th withdrawal day.Residues of ciprofloxacin in eggs were all lower than the minimum detection limit(0.01 mg/kg) at 9 th-10 th withdrawal day.With the increase of ciprofloxacin orally adminietered doses,residues of ciprofloxacin in eggs increased accordingly.