title: Solid-phase microextraction coupled with high performance liquid chromatography using on-line diode-array and electrochemical detection for the determination of fenitrothion and its main metabolites in environmental water samples.
abstract: The aim of this study was to develop a methodology for the analysis of the insecticide fenitrothion and its two main environmental metabolites, fenitrooxon and 3-methyl-4-nitrophenol. For this purpose, a solid-phase microextraction (SPME) method coupled to high performance liquid chromatography (LC) was optimized. Two on-line detectors, diode array (DAD) and direct current amperometrical (DCAD) were used in order to determine sensitivity and selectivity. The effects of the extraction parameters, including exposure and desorption time, pH, temperature, salt concentration and desorption mode on the extraction efficiency were studied. A satisfactory reproducibility for extractions from samples at 20 ppb-level with RSD < 12.5% (n = 10) was obtained. The calibration graphs were linear in the range of 10-1000 microg l(-1) and detection limits for the target compounds were between 1.2 and 11.8 microg l(-1) depending on which detector was used. The method was applied for determining fenitrothion and both its metabolites in river waters which run through forest areas near to aerial application of the pesticide.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, Paseo de la Universidad 7, 01007 Vitoria-Gasteiz, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Sánchez-Ortega
authors.forename: M C
authors.initials: MC
authors.lastname: Sampedro
authors.forename: N
authors.initials: N
authors.lastname: Unceta
authors.forename: M A
authors.initials: MA
authors.lastname: Goicolea
authors.forename: R J
authors.initials: RJ
authors.lastname: Barrio
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D005278:Fenitrothion / Q000032:analysis*; D007306:Insecticides / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007306:Insecticides; D014874:Water Pollutants, Chemical; D005278:Fenitrothion