Multiresidue method for simultaneous determination of quinolone antibacterials in pig kidney samples by liquid chromatography with fluorescence detection.

A new analytical method for simultaneous determination of eight quinolones namely, ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, oxolinic acid and sarafloxacin, in pig kidney samples was developed. The procedure involves the extraction of the quinolones from the samples by traditional extraction, a step for clean-up and preconcentration of the analytes by solid-phase extraction (SPE) and subsequent liquid chromatography separation with fluorescence detection (LC-FD). The mobile phase was composed of acetonitrile and 10 mM citrate buffer solution of pH 4.5, with an initial composition of acetonitrile-water 12:88 (v/v) and using linear gradient elution. Norfloxacin was used as internal standard. The limits of detection (1-8 microg kg(-1)) and the limits of quantification (5-27 microg kg(-1)) found were lower than the maximum residue limits regulated by the European Union for these compounds in pig kidney.

Multiresidue determination of quinolone antibacterials in eggs of laying hens by liquid chromatography with fluorescence detection.

An analytical method for the simultaneous determination of seven quinolones (ciprofloxacin, enrofloxacin, danofloxacin, difloxacin, flumequine, oxolinic acid and sarafloxacin) in egg samples of laying hens was developed. Their use is totally prohibited in animals from which eggs are produced for human consumption. Protein precipitation was achieved by addition of acetonitrile and ammonia, removal of acetonitrile with dichloromethane, the quinolones remaining in the basic aqueous extract. The aqueous extract was analysed by liquid chromatography with fluorescence detection (LC-FD). The mobile phase was composed of acetonitrile and 10 mM citrate buffer solution of pH 4.5, with an initial composition of acetonitrile-water (12:88, v/v) and using linear gradient elution. Norfloxacin was used as an internal standard. The limits of detection found were 4-12 ng g(-1). These values were lower than the maximum residue limits (MRLs) established by the European Union for these compounds in different tissues of eggs-producing animals.