Effects of extraction and spiking procedures on the determination of incurred residues of oxytetracycline in cattle kidney

Abstract

The effects of different extraction and spiking procedures on the determination of incurred oxytetracycline residues in animal tissues have been investigated. The extraction procedures investigated—direct aqueous or organic solvent extraction, enzymic digestion or sonication—all gave similar results for incurred oxytetracycline concentration in cattle kidney after correction for spike recovery. There was therefore no evidence for binding or conjugation of oxytetracycline in this tissue. Highest recovery from spiked tissue was obtained using ethyl acetate as extractant. The effects of spiking procedure (spike contact time, spike solvent and tissue state) on recovery from spiked cattle kidney were also small, indicating that added oxytetracycline spike does not interact with the tissue.