DETERMINATION OF TETRACYCLINE ANTIBIOTICS IN ANIMAL-TISSUES OF FOOD-PRODUCING ANIMALS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING SOLID-PHASE EXTRACTION

A high-performance liquid chromatographic (HPLC) method was developed for the determination of oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) residues in bovine and porcine muscles. The me thod involved the homogenization of the sample in EDTA-McIlvaine buffe r with added n-hexane and dichloromethane, centrifugation, precipitati on of the supernatant using trichloroacetic acid and filtration. Preco ncentration on Separcol SI C-18 cartridges improved the clean-up and t he recovery of tetracyclines that were separated by HPLC using the opt imized mobile phase of 0.01 M oxalic acid-acetonitrile-methanol (45:35 :20) on a Spherisorb ODS 2 column (250 x 4 mm I.D.). UV detection at 3 60 nm was applied with a detection limit of about 50 ng/g. The diode-a rray spectra confirmed the applicability of this method to the study o f tetracycline residues in carcasses.