Optimization of capillary zone electrophoresis separation and on-line preconcentration of 16 phenolic compounds from wines produced in South America

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A capillary zone electrophoresis method was optimized to simultaneously separate 16 phenolic compounds present in wines, as well as to evaluate sample on-line preconcentration for detectability improvement. The separated compounds were narirutin, (-)-epicatechin, (+)-catechin, rutin, kaempferol, myricetin, quercetin, morin, trans-resveratrol, cinnamic acid, ferulic acid, p-coumaric acid, vanillic acid, caffeic acid, gallic acid, and 3,4-dihydroxybenzoic acid. The optimized separation condition was 175 mmol L-1 boric acid at pH 9.0 and capillary of 50 mu m x 68 cm (60 cm effective length). The injection mode showing the greatest detectability (20 fold improvement) was hydrodynamic injection at 50 mbar for 30 s, followed by voltage inversion (-20 kV for 5 s) before the electrophoretic run. The method was validated and applied with success in a total of 23 samples of red, white, and rose wines. The developed method showed excellent applicability due to the simple extraction procedure and the low volume of reagents used, reducing expenses for reagents and technicians. (C) 2011 Elsevier Ltd. All rights reserved.451136144Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [04/10287-6