title: Development, validation and application of a SDME/GC-FID methodology for the multiresidue determination of organophosphate and pyrethroid pesticides in water.
abstract: A single-drop microextraction (SDME) procedure was developed for the analysis of organophosphorus and pyrethroid pesticides in water by gas chromatography (GC) with flame ionization detection (GC-FID). The significant parameters that affect SDME performance, such as the selection of microextraction solvent, solvent volume, extraction time, and stirring rate, were studied and optimized using a tool screening factorial design. The limits of detection (LODs) in water for the four investigated compounds were between 0.3 and 3.0 microgL(-1), with relative standard deviations ranging from 7.7 to 18.8%. Linear response data were obtained in the concentration range of 0.9-6.0 microg L(-1) (lambda-cyhalothrin), 3.0-60.0 microg L(-1) (methyl parathion), 9.0-60.0 microg L(-1) (ethion), and 9.0-30.0 microg L(-1) (permethrin), with correlation coefficients ranging from 0.9337 to 0.9977. The relative recoveries for the spiked water ranged from 73.0 to 104%. Environmental water samples (n=26) were successfully analyzed using the proposed method and methyl parathion presented concentration up to 2.74 microg L(-1). The SDME method, coupled with GC-FID analysis, provided good precision, accuracy, and reproducibility over a wide linear range. Other highlights of the method include its ease of use and its requirement of only small volumes of both organic solvent and sample.
authors.affiliation: Instituto de Química, Universidade Federal da Bahia, Salvador, BA, Brazil.
authors.forename: Anselmo de Souza
authors.initials: Ade S
authors.lastname: Pinheiro
authors.forename: Jailson B
authors.initials: JB
authors.lastname: de Andrade
mesh_terms: D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods; D008722:Methods; D010755:Organophosphates / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010755:Organophosphates; D010573:Pesticide Residues; D014874:Water Pollutants, Chemical