Chemical Analysis of Tetracycline Residues in Animal Tissues

Abstract

Abstract The common tetracyclines (TCs) which are used in agriculture, tetracycline, oxytetracycline, and chlortetracycline, are analyzed in animal tissues by using chemical-physical methods. Tissue from chicken, beef, pork, or fish is blended in aqueous HC1 and centrifuged. The supernate is adsorbed on an Amberlite X AD-2 column, the column is washed with water, and the TCs are eluted with methanol. For levels of TCs greater than 0.5 ppm in tissues and milk, the concentrated residue is spotted on a thin layer plate coated with kiesclguhr. The amount of TCs present on the developed plate is estimated by comparison of the fluorescence with standards spotted concurrently. Recovery of all 3 TCs from samples fortified at levels of 0.5-2 ppm is 45-80%. For levels less than 0.5 ppm, the residue from the Amberlite column is dissolved in pH 9 aqueous solution containing calcium ions and barbital, TCs are extracted into chloroformethanol, and the concentration is estimated on thin layer plates. Recoveries of TCs from various tissues at levels of 0.1–0.5 ppm are 10–35%.