title: Determination of pesticide residues in high oil vegetal commodities by using various multi-residue methods and clean-ups followed by liquid chromatography tandem mass spectrometry.
abstract: Several extraction methods were evaluated in terms of recoveries and extraction precision for 113 pesticides in avocado: QuEChERS with various d-SPE clean-ups (Z-Sep, Z-Sep+, PSA+C18 and silica), miniLuke and ethyl acetate. Extracts were analysed using liquid chromatography coupled with triple quadrupole mass spectrometer working in multi-reaction monitoring mode. Z-Sep and Z-Sep+ are new types of material for high lipid matrices - these two sorbents contain ZrO2, which improves fat removal from the extracts. The QuEChERS protocol with Z-Sep provided the highest number of pesticides with recoveries in the 70-120% range along with the lowest amount of coextracted matrix compounds. Subsequently, this method was validated in two matrices - avocado and almonds. In the validation recoveries at two levels - 10 and 50μg/kg - limit of quantitation, linearity, matrix effects, as well as the inter- and intraday precision were studied. In the avocado samples, 107 analytes had LOQs equal to 10μg/kg (signal to noise of quantitative transition was equal 20 or more). In the almond samples, 92 pesticides had LOQs equal to 10μg/kg (S/N≥20) and 2 pesticides at 50μg/kg. The validated method was employed in the analysis of real avocado and almond samples.
authors.affiliation: Pesticide Residue Research Group, European Union Reference Laboratory (EURL), Department of Hydrogeology and Analytical Chemistry, University of Almería, Ctra. Sacramento S/N°, La Cañada de San Urbano, 04120, Almería, Spain.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Rajski
authors.forename: Ana
authors.initials: A
authors.lastname: Lozano
authors.forename: Ana
authors.initials: A
authors.lastname: Uclés
authors.forename: Carmen
authors.initials: C
authors.lastname: Ferrer
authors.forename: Amadeo R
authors.initials: AR
authors.lastname: Fernández-Alba
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D005223:Fats / Q000302:isolation & purification; D057230:Limit of Detection; D027421:Persea / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D027861:Prunus / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D015040:Zirconium / Q000737:chemistry
chemical_list: D005223:Fats; D010573:Pesticide Residues; D015040:Zirconium; C028541:zirconium oxide
keywords: High oil matrices; LC–MS/MS; Multiresidue methods; Pesticides analysis