LIQUID-CHROMATOGRAPHIC ANALYSIS OF MULTIPLE SULFONAMIDE RESIDUES IN CHICKEN MUSCLE USING PRECOLUMN DERIVATIZATION AND FLUORESCENCE DETECTION

A rapid liquid chromatographic (LC) method is described fur the quanti tation of sulfadiazine, sulfamethazine, sulfadimethoxine, and sulfaqui noxaline residues in chicken muscle. The sulfonamides are extracted wi th chloroform, partitioned into hydrochloric acid, and submitted to pr e-column derivatization with fluorescamine. LC analysis of the fluores cent derivatives is performed on a C-18 column using a mobile phase of acetonitrile/20 mM phosphate buffer pH 4, (34/66, v/v), containing 20 mM octanesulfonate sodium salt. Owing to the sensitivity and selectiv ity of the fluorescence detection, residue levels of as low as 3 ng/g for sulfadiazine, 4 ng/g for sulfamethazine, 9 ng/g for sulfadimethoxi ne, and 40 ng/g for sulfaquinoxaline could be readily determined in ch icken muscle. Overall recoveries were found to be 77.7+/-4.8% for sulf adiazine. 84.6+/-4.2% for sulfamethazine, 92.3+/-4.1% for sulfadimetho xine, and 82.5+/-7.0% for sulfaquinoxaline. The linearity of the metho d was quite acceptable ill the range examined (5-100 ng/g for sulfadia zine and sulfamethazine, 15-150 ng/g for sulfadimethoxine, and 50-300 ng/g for sulfaquinoxaline).