Authors: T Galeano Díaz I Durán Merás D Airado Rodríguez
Publish Date: 2006/12/20
Volume: 387, Issue: 6, Pages: 1999-2007
Abstract
Basic studies on the photochemical behaviour of transresveratrol and its photoproduct are reported Photometrically and fluorimetrically calculated acidity constants of the former were determined The usefulness of the determination of resveratrol by photochemically induced fluorescence and secondderivative photochemically induced fluorescence was also examined The very weakly fluorescent transresveratrol is converted into a highly fluorescent photoproduct by irradiating hydroethanolic solutions of transresveratrol containing 40 v/v of ethanol for 60 s with intense UV radiation The photoproduct presents excitation and emission maxima centred at 260 nm and 364 and 382 nm respectively Under these conditions a linear relationship between fluorescence intensity and transresveratrol concentration was found between 66 and 66 ng mL−1 Optimum conditions for the extraction of transresveratrol from an aqueous phase at pH 50 with diethylether were a phase ratio aqueous/organic of 2 a shaking time of 60 s and a buffer concentration of 015 mol L−1 An extraction recovery of 100 was reached under these conditions The optimized extraction procedure was applied to the analysis of resveratrol in wine samples employing the amplitude between 356 and 364 nm of the secondderivative photoinduced emission spectrum as analytical signal It was found that there is not matrix effect and recoveries around 100 were obtained at different fortification levelsThe authors acknowledge to Consejería de Educación y Ciencia de la Junta de Extremadura Exp 2PR03A073 for financial support Diego Airado Rodríguez is grateful to the Consejería de Infraestructura y Desarrollo Tecnológico de la Junta de Extremadura for a fellowship DOE 22/06/04 Lda Dolores López Soto Viñaoliva SC is also thanked for providing wine samples
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