title: Multiresidue method for the analysis of multiclass pesticides in agricultural products by gas chromatography-tandem mass spectrometry.
abstract: A multiresidue method is described for determining 55 organophosphorus and organochlorinated compounds and pyrethroids commonly used in crop protection. Pesticide residues are extracted from samples with a mixture of ethyl acetate and sodium sulfate, obtaining a final preconcentration of I mg sample (ml extract)(-1). No additional clean-up steps are necessary. Analysis is performed by gas chromatography by using a combination of positive chemical ionisation (PCI) and electron impact (EI) ionisation modes and tandem mass spectrometry (GC-PCI/EI-MS-MS). Good sensitivity and selectivity of the method are obtained with limits of detection (LODs) ranging from 0.07 to 4.21 microg kg(-1) in all the cases, except for methamidophos, permethrin, cypermethrin and difenconazol. Average recoveries between 52 and 114% are obtained and good linearity is observed in the studied ranges (r > or = 0.994). The RSD values are < or = 29% in all the cases. The method has been applied to the analysis of 178 vegetable samples, as a part of the monitoring programme of the Association of Producers and Exporters of Fruits and Vegetables of Almería (COEXPHAL) and quality control systems applied during the assays have demonstrated a good performance and stability with time.
authors: Pesticide Residue Research Group, University of Almería, Spain.
authors: Ana
authors: A
authors: Agüera
authors: Mariano
authors: M
authors: Contreras
authors: Juan
authors: J
authors: Crespo
authors: Amadeo R
authors: AR
authors: Fernández-Alba
mesh_terms: D005506:Food Contamination; D008401:Gas Chromatography-Mass Spectrometry; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization; D014675:Vegetables
chemical_list: D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D010573:Pesticide Residues