A single run liquid chromatography-tandem mass spectrometry method for the analysis of varietal thiols and their precursors in wine

This research details the development of a novel LC-MS/MS method involving a QuEChERS-based extraction that, for the first time, achieves the fast and concurrent analysis of both free varietal thiols (3-sulfanylhexan-1-ol, 3-sulfanylhexyl acetate, and 4-methyl-4-sulfanylpentan-2-one) and their S-glutathionylated/S-cysteinylated precursors in wine samples. Limits of detections for the free thiols were comparable to or lower than those obtained with previously reported more laborious methods. Repeatability for the free thiols ranged between 3–19% and from 0.1–7.7% for the thiol precursors. The method was subsequently applied to the analysis of a selection of 22 wines from a range of different grape varieties. The rapidity of this method combined with its sensitivity makes it suitable for both research and industry applications.