Simultaneous determination of cis- and trans-resveratrol in wines by capillary zone electrophoresis

Abstract

A capillary zone electrophoresis method for determining cis- and trans-resveratrol isomers is proposed. Optimal conditions for the quantitative separation were investigated. A background electrolyte solution consisting of

40 mM borate buffer adjusted to pH 9.5, hydrodynamic injection and 5 kV of separation voltage were used. Good linearity and precision were obtained for the two isomers. Detection limits of 0.06 mg L^–1 for trans-resveratrol and 0.08 mg L^–1 for cis-reveratrol were obtained. The developed method is rapid and sensitive and it has been applied to determine cis- and trans-resveratrol in several red wines. The samples were purified and enriched by passing them through a preconditioned C₁₈ cartridge and eluting the isomers with acetonitrile–water (3 + 7).