title: Optimization of a solid-phase microextraction procedure for the determination of herbicides by micellar electrokinetic chromatography.
abstract: The use of a different optimization procedure that involves Experimental Design (ED) and Artificial Neural Networks (ANN) for the off-line coupling solid-phase microextraction-micellar electokinetic chomatography (SPME-MEKC) is presented. This combination of ED and ANN, mathematical tools not previously used in SPME-MEKC optimization, allowed us to obtain good extraction efficiencies in the SPME procedure for the determination of a group of eleven triazine herbicides in groundwater samples. Both extraction and desorption steps were carried out by solution stirring at 900 rpm. Optimal conditions for the off-line SPME procedure were: extraction with a poly(dimethylsiloxane)/divinylbenzene SPME fiber for 120 min, 10% (w/v) NaCl, desorption time 40 min, and 70% (v/v) of methanol/buffer as desorption mixture. Detection limits lay between 0.80 microg L(-1) and 4.89 microg L(-1). Finally, the optimized method was applied to the determination of these compounds in spiked and non-spiked groundwater samples using a previously optimized MEKC separation.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Science, Faculty of Chemistry, University of La Laguna, Av. Fco. Sánchez s/n, 38206 La Laguna, Tenerife, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Frías-García
authors.forename: M J
authors.initials: MJ
authors.lastname: Sánchez
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rodríguez-Delgado
mesh_terms: D002845:Chromatography / Q000295:instrumentation / Q000379:methods*; D006540:Herbicides / Q000032:analysis*; D016571:Neural Networks, Computer; D010573:Pesticide Residues / Q000032:analysis*; D014227:Triazines; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical
chemical_list: D006540:Herbicides; D010573:Pesticide Residues; D014227:Triazines; D014874:Water Pollutants, Chemical