Purge-and-Trap Coupled with Solid-phase Extraction and Fluorescence Detection (PT-SPE-FD) for the Analysis of Thiophenols in Wine: Toward a Field-Based Approach for Determination of Smoke Taint

Thiophenols have recently emerged as potential smoke taint markers in wine. Here, we report a rapid and accessible screening method for thiophenols in wine based on purge-and-trap solid-phase extraction coupled with fluorescence detection (PT-SPE-FD). In this method, volatile thiophenols are purged from wine samples, trapped on solid-phase extraction sorbents, eluted with methanol, and analyzed using a thiol-reactive fluorescent probe in a microplate format. The method exhibited a linear response between 0 and 75 μg L –1 and achieved a limit of detection of 280 ng L –1 . Application to Pinot Noir wines revealed increased fluorescence response in wine produced from smoke-exposed grapes compared to control wine ( p < 0.01), consistent with increased thiophenol fluorescence response. Recovery in spiked Pinot Noir was 95% with a relative standard deviation of 15%, demonstrating acceptable method performance in a complex matrix. Thus, this approach provides a rapid, low-cost, and practical screening tool for assessing thiophenols in wines.