Determination of Organophosphorous Pesticide Residues In Selected Fruits by Gas Chromatography - Mass Spectrometry
A multiresidue method for the determination of eight organophosphorous (OP) pesticide residues in selected Malaysian fruits is described. Residues are extracted from samples with 5% ethanol in ethyl acetate (v/v) and cleaned up by a Florisil column with 80 ml of 40% diethyl ether in petroleum ether (v/v). Analysis is performed by gas chromatography - mass spectrometry (GC-MS) using the selected ion monitoring (SIM) mode. Pesticides are positively confirmed by retention times and ion ratios. Recoveries were determined by spiking 4 matrices (papaya, Carica papaya; honeydew melon, Cucumis melo var. saccharinus; guava, Psidium guajava and belimbing, Averrhoa carambola) with target OP pesticides. Their recoveries ranged between 71% and 126% with coefficient of variations of 1.5% – 14.5%. Limits of detection ranged from 0.02 – 0.15 mg-1kg depending on the pesticide.