title: Multifunctional sorbents for the extraction of pesticide multiresidues from natural waters.
abstract: In this work multifunctional sorbents, based on surfactant-coated mineral oxides, are assessed for the simultaneous extraction/preconcentration of pesticide multiresidues from aqueous environmental samples. Seventeen pesticides, representative of all the common groups (triazines, phenylureas, carbamates, azols, anilides, chloroacetanilides, organophosphorous, phenoxyacids, aryloxy acids and phenols), are selected for this study. The sorbents assessed are pure sodium dodecyl sulphate (SDS) and mixed tetrabutylammonium (TBA)-SDS hemimicelles and/or admicelles adsorbed onto alumina. Because of their multifunctional character, these sorbents provide different retention mechanisms (i.e. hydrophobic, ionic and/or pi-cation interactions), which highly contribute to the efficient retention of pesticides with different polarities and acidities (bases, neutrals and acids). In addition, the low volume of eluent required for complete elution of analytes (typically 1-2mL) avoided the need of using time-consuming and tedious evaporation steps that generally are needed when cross-linked polymeric resins or carbon materials are used as sorbents. The performance of two sorbents, i.e. SDS and TBA-SDS mixed hemimicelles/admicelles, for the admicellar solid-phase extraction (ASPE) of pesticide multiresidue was comparatively investigated. The latter was selected on the basis of the higher breakthrough volumes permitted, the lower volume of eluent required and the higher sample and eluent flow rates allowed. The proposed ASPE/LC/UV approach provided detection limits lower than 100 ngL(-1) for the determination of the 17 pesticides tested. Recoveries from spiked (at the ngL(-1) level) river and underground water samples was quantitative for most of the pesticides tested.
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, Edificio Anexo Marie Curie, Campus de Rabanales, 14071-Córdoba, Spain.
authors.forename: Antonia
authors.initials: A
authors.lastname: Moral
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Sicilia
authors.forename: Soledad
authors.initials: S
authors.lastname: Rubio
authors.forename: Dolores
authors.initials: D
authors.lastname: Pérez-Bendito
mesh_terms: D002118:Calcium / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods; D007477:Ions; D007700:Kinetics; D008823:Micelles; D010573:Pesticide Residues / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D045483:Rivers; D012967:Sodium Dodecyl Sulfate / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013501:Surface-Active Agents; D014867:Water / Q000737:chemistry
chemical_list: D007477:Ions; D008823:Micelles; D010573:Pesticide Residues; D010575:Pesticides; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014867:Water; D012967:Sodium Dodecyl Sulfate; C009405:tetrabutylammonium; D002118:Calcium