title: Determination of pesticide residues in lettuce by gas chromatography with electron-capture detection.
abstract: A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesticides in different varieties of lettuce (Lactuca sativum) was developed. Lettuce samples were extracted by homogenization with acetone and partitioned into ethyl acetate-cyclohexane. Subsequent sample cleanup was not needed. Final determination was made by capillary gas chromatography (GC) with electron-capture detection (ECD). Confirmation analysis of pesticides was performed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recovery by the GC-ECD method obtained for these compounds varied from 66.4 to 119.2% with relative standard deviations < 7.7%. The GC-ECD method has good linearity, and the detection limit for the pesticides studied varied from 0.1 to 3.8 microg/kg. The proposed method was used to determine pesticide levels in different types of lettuce grown in soils from experimental fields.
authors.affiliation: Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/Mayor s/n, La Alberca, 30150 Murcia, Spain. jose.fenoll@carm.es
authors.forename: Jose
authors.initials: J
authors.lastname: Fenoll
authors.forename: Pilar
authors.initials: P
authors.lastname: Hellin
authors.forename: Josefa
authors.initials: J
authors.lastname: Lopez
authors.forename: Alberto
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Pilar
authors.initials: P
authors.lastname: Flores
mesh_terms: D002849:Chromatography, Gas; D004563:Electrochemistry; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D018545:Lactuca / Q000737:chemistry*; D013058:Mass Spectrometry; D010573:Pesticide Residues / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results; D012997:Solvents
chemical_list: D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D012997:Solvents