Multiresidue analysis of fluoroquinolone antibiotics in chicken tissue using liquid chromatography-fluorescence-multiple mass spectrometry

An efficient liquid chromatographic method for the multiresidue analysis of fluoroquinolone antibiotics in chicken tissue has been developed in which quantitation using fluorescence and confirmation with multiple mass spectrometry (MSn) was achieved simultaneously. Using this method, eight fluoroquinolones were analyzed in fortified samples of chicken liver and muscle tissue with recoveries at levels of 10–200 ng/g generally in the range of 60–93%, except for desethylene ciprofloxacin, which consistently gave recoveries ≥45%. Relative standard deviations were excellent in all cases, and the limits of detection in ng/g were determined as follows in liver and (muscle): desethylene ciprofloxacin 0.3 (0.1), norfloxacin 1.2 (0.2), ciprofloxacin 2 (1.5), danofloxacin 0.2 (0.1), enrofloxacin 0.3 (0.2), orbifloxacin 1.5 (0.5), sarafloxacin 2 (0.6), difloxacin 0.3 (0.2). Confirmation of the identities of the fluoroquinolones was achieved by monitoring the ratios of two prominent product ions in MS2 (desethylene ciprofloxacin) or MS3 (all others). Levels of confirmation as related to ion ratio variability criteria were established. Enrofloxacin and ciprofloxacin were also determined in enrofloxacin incurred chicken liver and muscle using this method.