DETERMINATION OF TETRACYCLINE RESIDUES IN ANIMAL-TISSUES BY LIQUID-CHROMATOGRAPHY

A simple liquid chromatographic (LC) method was developed for the dete rmination of tetracyclines (oxytetracycline, tetracycline and chlortet racycline) in animal tissues. Isolation of tetracyclines from biologic al matrices was performed with oxalic buffer followed by dechelation a nd deproteinization with oxalic acid - acetonitrile solution. For clea n-up solid phase extraction with a SDBI (styrene-divinylbenzene) cartr idge was used. LC analysis was performed on a polymeric analytical col umn (PLRP-S 5 mu m, 150 x 4.6mm) and using an oxalic acid mobile phase (0.01 M oxalic acid - acetonitrile 75:25, v/v), The whole procedure w as validated for intra- and inter-assay reproducibility determination by assaying muscle, liver and kidney samples supplemented with tetracy clines at the level of 50, 100 and 200 ng/g, respectively. The statist ical evaluation demonstrates high absolute recovery (> 80%) and low co efficient 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. (C) 1998 John Wil ey & Sons, Ltd.