Extraction and cleanup method optimization and validation in solid phase for determining organophosphorus insecticides on green onion (Allium fistulosum L.) and coriander (Coriandrum sativum L.)

An analytical method for extraction and cleanup of organophosphorus pesticides residues (OPs: diazinon, Malathion, parathion, disulfoton, fenitrothion, fenchlorphos, chlorfenvinphos, and methidathion) in green onion (Allium fistulosum L.) and coriander (Coriandrum sativum L.) was validated and optimized. The percentage of recovery of the OPs were calculated to evaluate the efficiency of the method, adding to 4g of sample of each matrix, free of insecticide residues, a known concentration of the OPs (0.2-10 mu g.g(-1)). The quantification was carried out employing capillary gas chromatography (GCC) with selective detection nitrogen phosphorus. The solid phase activated charcoal/florisil. (200:700mg), allowed the obtaining of highly percentages of recovery (96-105%) and clean extracts. The extraction method proposed showed a high precision in terms of repeatability (RSD <3%) and reproducibility (RSD<7%), and low detection limits (0.006-0.020 mu g.g(-1)), could be used for the routine monitoring of residual levels of OPs in the vegetable materials evaluated here in.