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 (beta-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.