title: Residue determination of captan and folpet in vegetable samples by gas chromatography/negative chemical ionization-mass spectrometry.
abstract: A gas chromatography/negative chemical ionization-mass spectrometry (GC/NCI-MS) method has been developed for the simultaneous determination of the fungicides captan and folpet in khaki (persimmon; flesh and peel) and cauliflower. Samples were extracted with acetone in the presence of 0.1 M zinc acetate solution in order to avoid degradation of fungicides and were purified using solid-phase extraction with divinylbenzene polymeric cartridges. Purified extracts were evaporated and dissolved in hexane prior to injection into the GC/NCI-MS system. Isotope-labeled captan and folpet were used as surrogate/internal standards, and quantification was performed using matrix-matched calibration. The method showed linear response in the concentration range tested (50-2500 ng/mL). The method was fully validated with untreated blank samples of khaki (flesh and peel) and cauliflower spiked at 0.05 and 0.5 mg/kg. Satisfactory recoveries between 82 and 106% and relative standard deviations lower than 11% in all cases (n = 5) were obtained. The limit of detection for both compounds were estimated to be 0.01 mg/kg. The developed method has been applied to treated and untreated samples collected from residue trials.
authors.affiliation: Universidad Jaume I, Research Institute for Pesticides and Water, 12071, Castellón, Spain. hernandf@exp.uji.es
authors.forename: Mercedes
authors.initials: M
authors.lastname: Barreda
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: López
authors.forename: Mercedes
authors.initials: M
authors.lastname: Villarroya
authors.forename: Joaquim
authors.initials: J
authors.lastname: Beltran
authors.forename: Jose María
authors.initials: JM
authors.lastname: García-Baudín
authors.forename: Felix
authors.initials: F
authors.lastname: Hernández
mesh_terms: D002138:Calibration; D002215:Captan / Q000032:analysis*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002849:Chromatography, Gas / Q000379:methods*; D005504:Food Analysis / Q000379:methods*; D006586:Hexanes / Q000737:chemistry; D008956:Models, Chemical; D010575:Pesticides / Q000032:analysis; D010797:Phthalimides / Q000032:analysis*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013696:Temperature; D014675:Vegetables; D014867:Water / Q000032:analysis; D019345:Zinc Acetate / Q000494:pharmacology
chemical_list: D006586:Hexanes; D010575:Pesticides; D010797:Phthalimides; D014867:Water; D002215:Captan; D019345:Zinc Acetate; C005020:folpet