Examinando por Autor "Bosque-Sendra, Juan Manuel"
Mostrando 1 - 2 de 2
- Resultados por página
- Opciones de ordenación
Ítem Dispersive liquid-liquid microextraction using a low density extraction solvent for the determination of 17 N-methylcarbamates by micellar electrokinetic chromatography-electrospray-mass spectrometry employing a volatile surfactant.(Elsevier, 2012-07) Moreno-González, David; Gámiz-Gracia, Laura; Bosque-Sendra, Juan Manuel; García-Campaña, Ana MaríaA new analytical method based on micellar electrokinetic chromatography tandem mass spectrometry (MEKC–ESI–MS/MS) employing a MS friendly surfactant (ammonium perfluorooctanoate) is proposed and validated for the identification and simultaneous quantification of 17 N-methylcarbamate pesticides in environmental and drinking water samples. MS/MS detection using an ion trap as analyzer operating in the multiple reaction monitoring mode was used. Different parameters were optimized in order to obtain an adequate CE separation combined with the highest sensitivity in MS/MS. Dispersive liquid–liquid microextraction (DLLME) using a low-density extraction solvent has been proposed for extraction, obtaining a preconcentration factor of 10. Under optimum conditions, recoveries for fortified samples ranged from 83% to 101%, with relative standard deviations lower than 8%. The limits of detection ranged from 1 to 144 ng l−1, demonstrating the sensitivity and applicability of this fast, simple, and environmentally friendly method.Ítem Use of dispersive liquid–liquid microextraction for the determination of carbamates in juice samples by sweeping-micellar electrokinetic chromatography(Springer, 2011-01-31) Moreno-González, David; Gámiz-Gracia, Laura; García-Campaña, Ana María; Bosque-Sendra, Juan ManuelDispersive liquid–liquid microextraction (DLLME) has been proposed for the extraction and preconcentra- tion of 12 carbamate pesticides in juice samples, followed by their determination by micellar electrokinetic chromatography with diode-array detection. To improve sensitivity, an on-capillary sample concentration method based on sweeping has been developed. Also, separations were performed in an extended light path fused-silica capillary; the separation buffer consisted of 100 mM borate and 50 mM SDS (pH 9.0) with 5% acetonitrile. Samples were introduced by hydrodynamic injection, dissolved in the separation buffer, but free of micelles. Several parameters of the DLLME procedure (such as type and volume of extraction and dispersive solvents, pH, salt addition, and extraction time) were optimized. Recoveries obtained for fortified juice samples (banana, pineapple, and tomato) at three different concentration levels, ranged from 78% to 105%, with relative standard deviations lower than 9%. The limits of detection ranged from 1 to 7 μg l−1. Moreover, the method is fast, simple, and environmentally friendly.