Abstract
The common tetracyclines (TCs) in fish tissues which are used in agriculture, tetracycline, oxytetracycline, and chlortetracycline, are analysed using an ODS-cartridge extraction device, and high performance thin layer chromatography (HPTLC) followed by densitometry. Fish tissue is blended in 0.1 M disodium ethylenediaminetetraacetate (di-Na EDTA)-McIlvaine buffer (pH 4.0) and centrifuged. The supernatant is adsorbed on the pretreated ODS-cartridge with 0.2 M di-Na EDTA aqueous solution, the cartrige is washed with water, and TCs are eluted with ethanol. The concentrated residue is spotted on a silica gel HPTLC plate predeveloped with saturated di-Na EDTA aqueous solution. The plate is then developed with chloroform-methanol-5% di-Na EDTA aqueous solution (65 : 20 : 5, lower layer). The amounts of TCs present on the developed plate are determined by ultraviolet absorption densitometry. Recoveries of TCs from fish samples fortified at level of 1 ppm are 60.2-78.6%.
