Determination of tetracycline residues in animal tissues by liquid chromatography

Abstract

A simple liquid chromatographic (LC) method was developed for the determination of tetracyclines (oxytetracycline, tetracycline and chlortetracycline) in animal tissues. Isolation of tetracyclines from biological matrices was performed with oxalic buffer followed by dechelation and deproteinization with oxalic acid – acetonitrile solution. For clean-up solid phase extraction with a SDBI (styrene-divinylbenzene) cartridge was used. LC analysis was performed on a polymeric analytical column (PLRP-S 5μm, 150 × 4.6 mm) and using an oxalic acid mobile phase (0.01 M oxalic acid – acetonitrile 75:25, v/v). The whole procedure was validated for intra- and inter-assay reproducibility determination by assaying muscle, liver and kidney samples supplemented with tetracyclines at the level of 50, 100 and 200 ng/g, respectively. The statistical evaluation demonstrates high absolute recovery (> 80%) and low coefficient of variation (< 10%) for all analysed samples. The detection limits for tetracyclines were 10–15 ng/g in muscle, and 20–25 ng/g in liver and kidney samples, depending on the analyte. © 1998 John Wiley & Sons, Ltd.