Abstract: An ion-pair high performance liquid chromatographic method with a fluorescence detector was established to determine four fluoroquinolone residues in fish. The chromatographic conditions were as follows: Waters μBondapakTM C18 column (3.9 mm i.d.×300 mm, 10 μm) was used at 40 ℃ with 11 mmol/L tetrabutylammonium bromide solution (pH 3.0)-acetonitrile (94∶6, v/v) as the mobile phase with a flow rate of 1.0 mL/min, at the excitation wavelength of 280 nm and emission wavelength of 460 nm. The detection limit for fish was 1 μg/kg. The linear range was from 6-100 μg/kg, and correlation coefficients were more than 0.9995. At the levels of 10, 50 and 100 μg/kg, the recoveries were 76%-100% with relative standard deviations of less than 7%. The method developed can meet the requirement for residue analysis.

Key words: ciprofloxacin, enrofloxacin, fish , norfloxacin, ofloxacin, ion-pair high performance liquid chromatography