Matrix solid-phase dispersion extraction versus solid-phase extraction in the analysis of combined residues of hexachlorocyclohexane isomers in plant matrices

This paper describes a method based on matrix solid-phase dispersion (MSPD) to determine the presence of combined residues of hexachlorocyclohexane (HCH) isomers,(alpha-, beta-, gamma- and delta-) in various:plant matrices including vegetables, fruits, leaves, grains and roots, by gas chromatography with Ni-63 electron-capture,detection. The MSPD method consists of sample homogenization, cellular disruption, exhaustive extraction, fractionation and clean up by simple,processes:in which a small amount of sample (5 g) was blended with Florisil and the,mixture passed into a small chromatographic column and,eluted with 10ml of n-hexane-ethyl acetate solvent mixture (70:30; v/v) and repeated with another 10ml of the same solvent mixture. A comparison with classical solid-phase extraction (SPE) showed MSPD to be efficient, fast, simple and,easy to perform. The,detection limit of various HCH isomers was-found lobe in the range of 2.15-5.68 ng and method detection limit varied-from 0.465 to 1.136 ng g(-1). Mean recoveries were found in,the range of 91-98%. Till date, there are no official methods or standards,by,Central Pollution Control Board or Bureau of Indian standards,that take into account India's real life conditions in the:analysis of pesticide residues in,plant matrices and the MSPD method described herein has proved to be a feasible one for the analysis of combined residues of HCH isomers in various plant materials. (c) 2007 Elsevier B.V. All rights reserved.