Effects of the matrix and sample preparation on the determination of fluoroquinolone residues in animal tissues

The effects of aqueous–organic solvent extraction and enzymic digestion sonication procedure on the isolation of spiked fluoroquinolones from poultry tissue have been studied. The highest recovery from spiked tissue was obtained using a mixture of trichloroacetic acid–acetonitrile (8:2) as extractant and an SDB1 cartridge for clean-up purposes. Validation data are presented for enrofloxacin, ciprofloxacin, sarafloxacin and difloxacin. The spiking procedure (spike contact time, spike solvent and matrix) had a small influence on the recovery of fluroquinolones from poultry muscle or liver. The effects of a different extraction on the determination of incurred enrofloxacin and its metabolite, ciprofloxacin, residues in poultry tissues have been investigated. The extraction procedures investigated – aqueous–organic solvent extraction, enzymic digestion or sonication – all gave similar results for incurred fluoroquinolone concentration in poultry muscle after correlation for spike recovery. The highest results were obtained in poultry liver when enzymic digestion has been used.