FLUOROMETRIC-DETERMINATION OF RESIDUAL ER YTHROMYCIN IN ANIMAL-DERIVED FOOD AFTER DERIVATIZATION WITH FMOC AND HPLC SEPARATION

A high-performance liquid chromatographic (HPLC) method for the determ ination of the macrolide antibiotic erythromycin in eggs, milk, swine muscle, kidney and liver was developed. The drug was extracted from th e matrix with acetonitrile. The raw extract was purified by liquid-liq uid partitioning and fractionation by reversed-phase HPLC for addition al cleanup. Erythromycin was reacted in a pre-column procedure with 9- fluorenylmethylchloroformate (FMOC) to enable fluorimetric detection ( excitation 255 nm, emission 315 nm) after isocratic separation on an a nalytical RP-18 HPLC column. Mean recoveries ranged from 99% at fortif ication levels of 0.03 mg/kg in egg to 38% at 0.06 mg/kg in liver. Wit h the exception of liver all detection limits were below 0.01 mg/kg an d precision for all other matrices and tested concentrations (0.015-0. 09 mg/kg) better than 20% (coefficient of variation).