RESUMEN
A high-performance liquid chromatographic (HPLC) method for the determination of the macrolide antibiotic erythromycin in eggs, milk, swine muscle, kidney and liver was developed. The drug was extracted from the matrix with acetonitrile. The raw extract was purified by liquid-liquid partitioning and fractionation by reversed-phase HPLC for additional 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 analytical RP-18 HPLC column. Mean recoveries ranged from 99% at fortification levels of 0.03 mg/kg in egg to 38% at 0.06 mg/kg in liver. With the exception of liver all detection limits were below 0.01 mg/kg and precision for all other matrices and tested concentrations (0.015-0.09 mg/kg) better than 20% (coefficient of variation).