Validation study for the determination of tetracycline residues in animal tissues

An interlaboratory study of the liquid chromatographic (LC) determination o f tetracyclines-oxytetracycline (OTC), tetracycline (TTC), and chlortetracy cline (CTC)-in animal tissues was conducted. Isolation was performed with o xalic buffer followed by dechelation and deproteination with oxalic acid-ac etonitrile. The extract was cleaned with a styrene-divinylbenzene cartridge . LC analysis was performed with a PLRP-S column and 0.01M oxalic acid-acet onitrile (75 + 25, v/v) as mobile phase. Participants analyzed 2 control an d 10 fortified porcine muscle and kidney samples. Additionally, porcine mus cle samples containing incurred residues of tetracyclines were analyzed. Me an recoveries of fortified residues from porcine tissue ranged from 76.00 t o 86.89%. Repeatabilities varied from 2.05% for OTC to 3.61% for TTC for mu scle samples and from 6.75% for CTC to 8.74 for OTC for kidney samples. Rep roducibilities ranged from 2.05 to 4.30% for muscle samples and from 15.77 to 18.81% for kidney samples.