Planar chromatography for the multiclass, multiresidue screening of chloramphenicol, nitrofuran, and sulfonamide residues in pork and beef

Abstract

A method is described for multiclass and multiresidue qualitative detection of chloramphenicol, nitrofuran, and sulfonamide residues in animal muscle. The drugs are extracted from 1 g tissue with 2 mL ethyl acetate and purified by silica solid-phase extraction. After elution of the cartridge, the collected solution is evaporated, and the residue is dissolved in methanol and chromatographed on a Si60 high-performance thin-layer chromatography plate. After evaporation of solvent, nitrofurans are visualized first by their specific UV photochemical reaction with pyridine. Then chloramphenicol is reduced to its amino derivative, and this derivative and the sulfonamides are visualized by long-wave UV after reaction with fluorescamine. Chloramphenicol, nitrofurans, and sulfonamides are detected at residue level of 10, 5, and 100 micrograms/kg, respectively, or less in pork and beef.