title: Multi-analyst, multi-matrix performance of the QuEChERS approach for pesticide residues in foods and feeds using HPLC/MS/MS analysis with different calibration techniques.
abstract: Three different calibration approaches were applied in HPLC/MS/MS using electrospray ionization for the determination of 14 diverse pesticide residues at different levels in a variety of food matrixes. This study was conducted as part of a 4 day training course for 17 chemists to learn the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach to pesticide residue analysis in foods. The analysts were divided into four different teams for the analysis of 12 different matrixes (strawberries, plums, carrots, green peppers, milk, molasses, alfalfa oats, corn silage, dry pet food, soybean, almonds, and foliage). The acetate-buffered QuEChERS protocol gave excellent results in the spiked samples for all matrixes tested. The HPLC/MS/MS calibration techniques consisted of external standardization in solvent solutions, matrix-matching, and the echo-peak technique. Peak areas were normalized to an internal standard in all three approaches. Matrix effects were observed with the corn silage, carrot, and foliage extracts, but they were minimal or nonexistent in the other matrixes. Matrix-matching best compensated for matrix effects, but has logistical difficulties in real-world application and required extra sample preparation compared to the other approaches. The echo-peak technique reduced matrix effects but did not eliminate them.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Lehotay
authors.forename: Katerina
authors.initials: K
authors.lastname: Mastovska
authors.forename: Alan R
authors.initials: AR
authors.lastname: Lightfield
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gates
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005504:Food Analysis; D005506:Food Contamination; D005638:Fruit; D007477:Ions; D010573:Pesticide Residues / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors; D014675:Vegetables
chemical_list: D007477:Ions; D010573:Pesticide Residues; D012997:Solvents