| Title: | Quantification of Polyfunctional Thiols in Wine by HS-SPME-GC-MS Following Extractive Alkylation |
| Author(s): | Musumeci LE; Ryona I; Pan BS; Loscos N; Feng H; Cleary MT; Sacks GL; |
| Address: | "Department of Food Science, Cornell University, Stocking Hall, 411 Tower Road, Ithaca, NY 14853, USA. lem248@cornell.edu. Department of Food Science, Cornell University, Stocking Hall, 411 Tower Road, Ithaca, NY 14853, USA. ir45@cornell.edu. Gallo Winery, 600 Yosemite Boulevard, Modesto, CA 95354, USA. Bruce.Pan@ejgallo.com. Gallo Winery, 600 Yosemite Boulevard, Modesto, CA 95354, USA. Natalia.Loscos@ejgallo.com. Gallo Winery, 600 Yosemite Boulevard, Modesto, CA 95354, USA. Hui.Feng@ejgallo.com. Gallo Winery, 600 Yosemite Boulevard, Modesto, CA 95354, USA. Mike.Cleary@ejgallo.com. Department of Food Science, Cornell University, Stocking Hall, 411 Tower Road, Ithaca, NY 14853, USA. gls9@cornell.edu" |
| DOI: | 10.3390/molecules200712280 |
| ISSN/ISBN: | 1420-3049 (Electronic) 1420-3049 (Linking) |
| Abstract: | "Analyses of key odorous polyfunctional volatile thiols in wines (3-mercaptohexanol (3-MH), 3-mercaptohexylacetate (3-MHA), and 4-mercapto-4-methyl-2-pentanone (4-MMP)) are challenging due to their high reactivity and ultra-trace concentrations, especially when using conventional gas-chromatography electron impact mass spectrometry (GC-EI-MS). We describe a method in which thiols are converted to pentafluorobenzyl (PFB) derivatives by extractive alkylation and the organic layer is evaporated prior to headspace solid phase microextraction (HS-SPME) and GC-EI-MS analysis. Optimal parameters were determined by response surface area modeling. The addition of NaCl solution to the dried SPME vials prior to extraction resulted in up to less than fivefold improvement in detection limits. Using 40 mL wine samples, limits of detection for 4-MMP, 3-MH, and 3-MHA were 0.9 ng/L, 1 ng/L, and 17 ng/L, respectively. Good recovery (90%-109%) and precision (5%-11% RSD) were achieved in wine matrices. The new method was used to survey polyfunctional thiol concentrations in 61 commercial California and New York State wines produced from V. vinifera (Riesling, Gewurztraminer, Cabernet Sauvignon, Sauvignon blanc and non-varietal rose wines), V. labruscana (Niagara), and Vitis spp. (Cayuga White). Mean 4-MMP concentrations in New York Niagara (17 ng/L) were not significantly different from concentrations in Sauvignon blanc, but were significantly higher than 4-MMP in other varietal wines" |
| Keywords: | Alkylation Gas Chromatography-Mass Spectrometry/*methods Limit of Detection Reproducibility of Results Solid Phase Microextraction/*methods Sulfhydryl Compounds/*analysis Wine/*analysis Vitis labruscana extractive alkylation polyfunctional thiols wine; |
| Notes: | "MedlineMusumeci, Lauren E Ryona, Imelda Pan, Bruce S Loscos, Natalia Feng, Hui Cleary, Michael T Sacks, Gavin L eng Switzerland 2015/07/15 Molecules. 2015 Jul 6; 20(7):12280-99. doi: 10.3390/molecules200712280" |
