title: Single drop microextraction and gas chromatography-mass spectrometry for the determination of diflufenican, mepanipyrim, fipronil, and pretilachlor in water samples.
abstract: An analytical method for the determination of diflufenican, mepanipyrim, pretilachlor, and fipronil in water samples was developed using single drop microextraction in the direct immersion mode and gas chromatography-mass spectrometry. A factorial fractionated design of type 2(6-1) at two levels was performed, to study the influence of experimental variables such as ionic strength, pH, agitation speed, extraction time, drop volume, and sample volume. To establish the optimal conditions for the variables that were significant, a Doehlert design was performed. The optimum conditions of extraction were 1 μL of heptane immersed in 4.0 mL of sample with continuous agitation at 500 rpm for 30 min at room temperature. The developed method proved to have good linearity for the range studied. The detection limits were 0.07 μg L(-1) for diflufenican, 0.03 μg L(-1) for mepanipyrim, 0.08 μg L(-1) for pretilachlor, and 1.39 μg L(-1) for fipronil. The method was validated on river water samples, showing the absence of matrix effect and recoveries ranged from 90.1 to 107.8 %. The results show that the method developed is accurate, sensitive, rapid, simple, and low cost, so it is recommended for application in the analysis of these different classes of pesticides in water samples.
authors.affiliation: Laboratory of Analytical Chemistry and Electrochemistry, Faculty of Engineering, University of Zulia, P.O. Box 4011-A-526, Maracaibo, Venezuela, laraujo@fing.luz.edu.ve.
authors.forename: Lilia
authors.initials: L
authors.lastname: Araujo
authors.forename: María E
authors.initials: ME
authors.lastname: Troconis
authors.forename: Dalia
authors.initials: D
authors.lastname: Cubillán
authors.forename: Jair
authors.initials: J
authors.lastname: Mercado
authors.forename: Noreiva
authors.initials: N
authors.lastname: Villa
authors.forename: Avismelsi
authors.initials: A
authors.lastname: Prieto
mesh_terms: D000083:Acetanilides / Q000032:analysis; D005591:Chemical Fractionation / Q000379:methods*; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D009536:Niacinamide / Q000031:analogs & derivatives / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D011720:Pyrazoles / Q000032:analysis; D011743:Pyrimidines / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D000083:Acetanilides; D010575:Pesticides; D011720:Pyrazoles; D011743:Pyrimidines; D014874:Water Pollutants, Chemical; D009536:Niacinamide; C072847:diflufenican; C118050:pretilachlor; C104083:mepanipyrim; C082360:fipronil