Analysis of fluoroquinolone residues in edible chicken tissues using supercritical fluid extraction

We evaluated a procedure that uses high-performance liquid chromatography to determine the levels of four fluoroquinolones (ciprofloxacin, enrofloxacin, norfloxacin, and ofloxacin) remaining in chicken breast muscle, liver, and kidneys after the analytes are extracted using supercritical fluid extraction (SFE). These antimicrobial fluoroquinolones were extracted by SFE using supercritical CO2 containing 30% (v/v) methanol. The recovery, limit of detection, accuracy, and precision of this method were evaluated on the basis of fortified matrices at concentrations of 25 to 250 microg/kg. The method is validated and shown to be linear in the range of 2.5-50 microg/kg. Spike recoveries for muscle, liver and kidney samples prepared at 4 spiking levels were ranged from 56.6-104.3%, 51.2-98.4% and 62.2-97.8%, respectively. The coefficient of variation (CV) for recovery as a measure of relative variability was between 3% and 13%, and the relative standard deviation (RSD) was < 20%. The limits of quantitation (LOQ) were 10 microg/kg for enrofloxacin, 12.5 microg/kg each for ciprofloxacin and norfloxacin and 25 microg/kg for ofloxacin; these values were lower than the maximum residue levels (MRLs) authorized by the European Community. The 4 compounds were evaluated simultaneously, and the method was shown to be applicable for analyzing their residues in edible chicken tissues.