DETERMINATION OF METHOXYPYRAZINES IN RED WINES BY STABLE-ISOTOPE DILUTION GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

Quantitative analysis of methoxypyrazines in a range of red wines is reported for the first time. By stable isotope dilution gas chromatography-mass spectrometry, 2-methoxy-3-(2-methylpropyl) pyrazine was determined in 12 Australian and New Zealand Cabernet Sauvignon wines (mean concentration, 19.4 ng/L) and in 6 Bordeaux wines that are blends, to varying degrees, of Cabernet Sauvignon, Merlot, and Cabernet Franc (mean concentration, 9.8 ng/L). These findings suggest that the concentration of the methoxypyrazine in wines of these varieties is ca. 30 times lower than that indicated in a previous study. In these 18 wines, the concentration of the methoxypyrazine exceeded its sensory detection threshold in water, consistent with its contributing to wine flavor. The concentration two French Pinot noir wines was below the sensory detection threshold. In all wines, the level of 2-methoxy-3-(1-methylpropyl)pyrazine was less than 2 ng/L.