Comparison of Different Extraction Methods Applied to Volatile Compounds in Wine Samples Previous to the Determination by Gas Chromatography

Abstract

This paper describes the optimization and comparison of discontinuous liquid-liquid extraction, continuous liquid-liquid extraction and solid-phase extraction as methods for separating and concentrating volatile compounds from wine. The study has been applied to 11 compounds present in wine: 3-methyl-butyl acetate, 3-methyl-1-butanol, ethyl hexanoate, 1-hexanol, ethyl octanoate, diethyl succinate, 2-phenyl-ethyl acetate, hexanoic acid, 2-phenyl-ethanol, octanoic acid, and decanoic acid. These compounds were selected from those identified by gas chromatography-mass spectrometry (GC-MS) analysis of a natural wine sample. Factors such as the sample volume, the extraction time, and the solvent volume were considered. In all cases, the determination was performed by gas chromatography, using a flame ionization detector and the internal standard method (3-octanol) as the quantification procedure. The optimization study was performed with synthetic wine samples containing all the volatile compounds under study. The solid-phase extraction was subsequently applied to samples of red wines from La Rioja.