Analysis of pesticide residues in rice using matrix solid-phase dispersion (MSPD)

this work reports a multi-residue extraction method based on matrix solid-phase dispersion (mspd) and capillary gas chromatography - electron capture detection for quantification of two widely used organophosphorus insecticides (malathion and parathion-methyl) and an organochlorine pesticide (b-endosulfan) in rice. a set of experiments was done with a spiked matrix with a standard mix, varying sample and solid phase amounts, solid phase and eluting solvent. analyses of fortified rice samples were performed at different levels (0.5-10.0 mg kg-1). mean recoveries from three replicates ranged from 75.5% to 116.0%, with coefficients of variation from 0.5% to 10.9%. the limit of detection was in the range of 20 to 105 pg for the pesticides. commercial rice was analyzed for method application.