DETERMINATION OF CLORSULON RESIDUES IN MILK USING A SOLID-PHASE EXTRACTION CLEANUP AND LIQUID-CHROMATOGRAPHIC DETERMINATION

A method for the isolation and liquid chromatographic determination of the antiparasitic drug clorsulon in milk is presented. Milk samples are deproteinized and the supernatant is purified by solid-phase extraction (SPE). The purified extracts are quantified by HPLC analysis with UV detection. The overall recovery of clorsulon from 30 control milk samples spiked at 25-200 ppb was 77.0% (C.V.- 5.3%). This method, a liquid-liquid extraction method, and a matrix solid phase dispersion (MSPD) method for the determination of clorsulon in milk gave comparable values for milk samples with incurred clorsulon residues. However, the SPE method uses less solvent and is more rapid than the liquid-liquid extraction method and is more sensitive than the MSPD method.