Development and Validation of a GC-MS/MS Method for cis- and trans-Resveratrol Determination: Application to Portuguese Wines

Abstract

Resveratrol is a naturally occurring phytoalexin produced by the Vitis vinifera L. plant. It exists as two isomers (cis and trans), both present in wines. This work describes the development and validation of a GC-MS/MS analytical procedure for their determination in wines, which include five steps for sample preparation: pre-treatment, SPE extraction, acetyl derivatization, liquid/liquid extraction, and sample concentration. The developed GC-MS/MS method showed to be linear, with coefficients of determination higher than 0.99 for both isomers, and sensible in the range from 1.0 to 2000.0 μg/L for cis-resveratrol and 5.0 to 2000.0 μg/L for trans-resveratrol. Intra- and inter-day precision evaluation resulted in coefficient of variation values (CV) lower than 15%. The validated methodology was then applied in the determination of resveratrol in 33 red wines (from 8 Portuguese Protected Geographical Indications). For cis-resveratrol the content ranged from 45.8 to 2439.5 μg/L, while for trans-resveratrol it ranged from 45.8 to 2385.0 μg/L. No statistically significant differences were found between the studied regions.