title: Determination of fenthion and fenthion-sulfoxide, in olive oil and in river water, by square-wave adsorptive-stripping voltammetry.
abstract: Square-wave adsorptive-stripping voltammetry technique has been used to develop a method for the determination of fenthion in olive oil. Due to the fact that fenthion does not give any electrochemical signal at mercury electrode, the method has been based on a previous oxidation of fenthion to its metabolite, fenthion-sulfoxide, by using KMnO(4). The metabolite gives rise to a peak due to an adsorptive-reductive process at -0.786 V. Fenthion is isolated from olive oil by carrying out a solid-liquid extraction procedure using silica cartridge, followed by a liquid-liquid partitioning with acetonitrile. The detection limit in olive oil is 78.8 ng g(-1) and recoveries for four levels of fortification are ranged from 85% to 109%. On the other hand, it has been developed a method for the simultaneous determination of fenthion and its metabolite fenthion-sulfoxide, in river water. Pesticides are isolated from water by carrying out a liquid-liquid partitioning with trichloromethane. The detection limits are 0.41 ng g(-1) and 0.44 ng g(-1), for fenthion and fenthion-sulfoxide, respectively. Recoveries for three levels of fortification are ranged from 96% to 103% for fenthion and 94% to 104% for fenthion-sulfoxide.
authors.affiliation: Department of Analytical Chemistry, University of Extremadura, Avd. Elvas s/n 06071, Badajoz, Spain. tgaleano@unex.es
authors.forename: T Galeano
authors.initials: TG
authors.lastname: Díaz
authors.forename: A Guiberteau
authors.initials: AG
authors.lastname: Cabanillas
authors.forename: M D López
authors.initials: MD
authors.lastname: Soto
authors.forename: J M
authors.initials: JM
authors.lastname: Ortiz
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000327:Adsorption; D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000379:methods; D004563:Electrochemistry / Q000379:methods; D005284:Fenthion / Q000032:analysis*; D005504:Food Analysis / Q000379:methods*; D005618:Fresh Water; D006863:Hydrogen-Ion Concentration; D000069463:Olive Oil; D010573:Pesticide Residues / Q000032:analysis; D010938:Plant Oils / Q000378:metabolism*; D045483:Rivers; D012451:Safrole / Q000031:analogs & derivatives* / Q000032:analysis; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000069463:Olive Oil; D010573:Pesticide Residues; D010938:Plant Oils; D014867:Water; D005284:Fenthion; D012451:Safrole; C005746:sulfoxide; C032159:acetonitrile