Direct continuous supercritical fluid extraction as a novel method of wine analysis: Comparison with conventional indirect extraction and implications for wine variety identification

Direct supercritical fluid extraction (SFE) of wines with carbon dioxide was compared to SFE of the sorbent used for solid-phase extraction of the same wine samples (SPE–SFE). Compared to SPE–SFE, the direct SFE results in a more specific and representative gas chromatographic fingerprint of the wine sample. The multivariate statistical processing of the direct SFE–GC data provides a clear-cut and sharp discrimination among the individual wine varieties while the discrimination based on the SPE–SFE–GC data is relatively poor. This finding reflects the adverse effects of additional analyte–sorbent interactions and sorption/desorption steps involved in SPE–SFE.