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 developed for the determination of ivermectin (IVM) residues in fish muscle tissue. The extraction and clean-up procedure is based on the matrix solid phase dispersion technique. Control and IVM-fortified fish muscle samples (0.5 g) are blended with octadecyl (C18 end-capped) packing material. A column made from the C18-fish tissue blend is washed with hexane (8 ml) and the IVM is eluted with 8 ml of dichloromethane-ethyl acetate (3 + 1). Ivermectin is derivatized and analyzed by high-performance liquid chromatography (HPLC) with fluorescence detection. The recovery from fortified samples was greater than 80% in the concentration 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 extraction 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 makes it an attractive and useful method for routine analysis of IVM in fish muscle tissue.