title: An evaluation method for determination of non-polar pesticide residues in animal fat samples by using dispersive solid-phase extraction clean-up and GC-MS.
abstract: A rapid and easy method has been proposed, optimized and evaluated for quantitative determination at trace level of a representative group of non-polar pesticides in fat samples. The method includes n-hexane-saturated acetonitrile extraction, fat precipitation by cooling pre clean-up followed by dispersive solid-phase extraction (d-SPE) based on QuEChERS procedure clean-up. Determination was performed by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Efficiency of the d-SPE clean-up step was evaluated by comparison with fat oxidation treatment and gel permeation chromatography. Different combinations of d-SPE extraction reagents and sample amounts were tested in order to minimize matrix co-extractives and interferences. Best recoveries were obtained with 1200 mg of MgSO(4), 400 mg of end-capped C(18), 400 mg of PSA and 1 g of sample amount. SIM method, matrix effect, precision, and accuracy were evaluated with spiked pork fat samples for 38 representative pesticides. Results of this study showed that this technique is applicable in routine analysis for its application into monitoring programs. It simplifies time-consuming clean-up steps and allows a satisfactory long-term chromatographic performance.
authors.affiliation: Public Health Research Center of Valencia (CSISP), Food Safety Area, Av. Cataluña, 21, 46020 Valencia, Spain. castillo_mer@gva.es
authors.forename: Mercedes
authors.initials: M
authors.lastname: Castillo
authors.forename: Carmen
authors.initials: C
authors.lastname: González
authors.forename: Ana
authors.initials: A
authors.lastname: Miralles
mesh_terms: D000097:Acetonitriles; D000818:Animals; D005223:Fats / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000191:economics / Q000379:methods*; D006586:Hexanes; D008461:Meat Products / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis* / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000191:economics / Q000379:methods*; D013552:Swine
chemical_list: D000097:Acetonitriles; D005223:Fats; D006586:Hexanes; D010573:Pesticide Residues; C026385:n-hexane; C032159:acetonitrile