APPLICATION OF THE MATRIX SOLID-PHASE DISPERSION TECHNIQUE FOR THE DETERMINATION OF IVERMECTIN RESIDUES IN FISH MUSCLE-TISSUE

A modified high-performance liquid chromatographic method has been dev eloped for the determination of ivermectin (IVM) residues in fish musc le tissue. The extraction and clean-up procedure is based on the matri x solid phase dispersion technique. Control and IVM-fortified fish mus cle samples (0.5 g) are blended with octadecyl (C-18 end-capped) packi ng material. A column made from the C-18-fish tissue blend is washed w ith hexane (8 mi) and the IVM is eluted with 8 mi of dichloromethane-e thyl acetate (3 + 1). Ivermectin is derivatized and analyzed by high-p erformance liquid chromatography (HPLC) with fluorescence detection. T he recovery from fortified samples was greater than 80% in the concent ration range 20-100 ng g(-1) of tissue. The limit of determination was 10 ng g(-1) of tissue. This method and another, using solvent extract ion and clean-up of the extract on a solid phase extraction cartridge, gave comparable results for an incurred sample containing IVM residue . This method incorporates a rapid sample pre-treatment step which mak es it an attractive and useful method for routine analysis of IVM in f ish muscle tissue.