title: Multiresidue analysis of pesticides in animal liver by gas chromatography using triple quadrupole tandem mass spectrometry.
abstract: Two methods for extracting organochlorine (OCs) and organophosphorus (OPs) pesticides from animal liver have been developed. The determination was carried out by gas chromatography with electron impact ionization tandem mass spectrometry (GC-(EI-)MS/MS) using a triple quadrupole (QqQ) analyzer. First, a liquid-solid extraction performed with a high-speed homogenizer (Polytron) using ethyl acetate as solvent, and a subsequent clean-up by gel permeation chromatography (GPC) was applied, determining 34 pesticides. Secondly, a matrix solid phase dispersion (MSPD) extraction with octadecylsilyl (C(18)) sorbent combined with a Florisil clean-up and ethyl acetate elution was performed, analyzing 25 compounds. These methodologies have been tested and compared in the sample pre-treatment due to the fatty nature of the matrix. The GPC method was finally selected and validated, yielding recoveries in the range 70-115%, with precision values expressed as relative standard deviation (RSD) lower or equal to 20%, at the spiking levels of 25 and 50 microg kg(-1), and limits of quantification (LOQs) lower than the maximum residue levels (MRLs) set by the European Union in animal products, except for isofenphos. Linearity was also studied ranging between 5 and 300 microg kg(-1) for most of pesticides. This method was applied to the analysis of real liver samples of chicken, pork and lamb.
authors.affiliation: Analytical Chemistry of Pollutants Research Group (ISO 9001 Certificate), Department of Analytical Chemistry, University of Almería, 04120 Almería, Spain. agarrido@ual.es
authors.forename: Antonia Garrido
authors.initials: AG
authors.lastname: Frenich
authors.forename: Patricia Plaza
authors.initials: PP
authors.lastname: Bolaños
authors.forename: José Luis Martínez
authors.initials: JL
authors.lastname: Vidal
mesh_terms: D053000:Analytic Sample Preparation Methods; D000818:Animals; D002645:Chickens; D002850:Chromatography, Gel; D004726:Endosulfan / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006846:Hydrocarbons, Halogenated / Q000032:analysis; D008099:Liver / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D012756:Sheep; D034421:Sus scrofa; D053719:Tandem Mass Spectrometry / Q000379:methods*; D035501:Uncertainty
chemical_list: D006846:Hydrocarbons, Halogenated; D010573:Pesticide Residues; D004726:Endosulfan