Determination of Residual Tetracyclines in Meats by High Performance Liquid Chromatography

A simple and sensitive method for determination of residual tetracyclines (TCs) in meats by high performance liquid chromatography (HPLC) after chelate formation with magnesium ion was developed.Oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in a sample were extracted with McIlvaine buffer (pH 5.5)-methanol (3:7). The extract was concentrated and defatted with petroleum ether. The defatted solution was passed through a Sep-pak C18 cartridge. After washing the cartridge with water, TCs were eluted with methanol. The eluate was evaporated to dryness. The residue was dissolved in 1M imidazole buffer containing 50mM magnesium acetate-methanol (77:23), and the solution was injected into a YMC-PACK ODS HPLC column. TCs were separated with 1M imidazole buffer containing 50 mM magnesium acetate-methanol (77:23) as a mobile phase and detected with a flourometric detector.The recoveries of TCs from beef fortified with 0.5, 2ppm of OTC and TC and 2, 10ppm of CTC were 81.7-82.8% for OTC, 65.9-80.7% for TC and 53.0-80.1% for CTC.