Optimization of a solid-phase microextraction procedure for the determination of herbicides by micellar electrokinetic chromatography |
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Authors: | Frías-García Sergio Sánchez M J Rodríguez-Delgado Miguel A |
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Institution: | 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. |
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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. |
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Keywords: | Solid-phase microextraction Experimental design Artificial neural networks Triazines Micellar electrokinetic chromatography |
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