DEVELOPMENT AND VALIDATION OF AN LC-DAD METHOD FOR THE ROUTINE ANALYSIS OF RESIDUAL QUINOLONES IN FISH EDIBLE TISSUE AND FISH FEED. APPLICATION TO FARMED GILTHEAD SEA BREAM FOLLOWING DIETARY ADMINISTRATION

Abstract

The authors in a previous work had reported on the determination of seven quinolone antibiotics in gilthead sea bream using liquid chromatography–tandem mass spectrometry, which is a rather expensive and not always available analytical technique. In this work, photodiode array detection is used, so that no sophisticated instrumentation is necessary, following the same sample preparation procedure. A high performance liquid chromatography method for the determination of seven quinolone antibiotics in fish feed and gilthead sea bream (Sparus aurata L.) tissue was developed and validated in terms of selectivity, linearity, accuracy, precision, sensitivity, robustness, and stability, according to European Decision 2002/657/EC. Ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine were separated on a Perfectsil ODS-3 (250 mm × 4 mm, 5 µm) column by gradient elution, using a mobile phase consisting of 0.1% trifluoroacetic acid (pH = 1), acetonitrile, and methanol at 25°C. Analytes were monitored by diode array detector at 255 nm for acidic quinolones (oxolinic acid, nalidix acid, and flumequine) and 275 nm for ciprofloxacin, danofloxacin, enrofloxacin, and sarafloxacin. The method was successfully applied to gilthead sea bream from aquaculture after dietary administration of flumequine and oxolinic acid.