Quantitative analysis of 4-ethylphenol and 4-ethylguaiacol in red wine

2,3,5,6-[H-2(4)]-4-Ethylphenol (d(4)-4-ethylphenol) was synthesised for use as an internal standard in a new, rapid and accurate analytical method, em ploying gas chromatography-mass spectrometry to determine the concentration of the important aroma compounds 4-ethylphenol and 4-ethylguaiacol in red wine. The concentrations of both compounds in wine stored in 44 American an d 47 French new and used oak barrels from several suppliers were measured. Wine stored in shaved and refired oak barrels contained up to 85% less 4-et hylphenol and 4-ethylguaiacol than wine stored in normal barrels of the sam e age that were not shaved. The concentration of 4-ethylphenol found in 61 bottled commercial Australian red wines of various ages ranged from 2 mu g/ l in a Merlot up to 2660 mu g/l in a Shiraz, with a mean concentration of 7 95 mu g/l. 4-Ethylguaiacol was also detected in every red wine analysed, ra nging in concentration from 1 mu g/l (in a Pinot Noir) up to 437 mu g/l (in a Merlot) with a mean concentration of 99 mu g/l. (C) 2000 Elsevier Scienc e BN. All rights reserved.