STABLE CARBON-ISOTOPE CONTENT IN ETHANOL OF EC DATA-BANK WINES FROM ITALY, FRANCE AND GERMANY

In the present work we discuss the usefulness of carbon isotope analys is of wine ethanol for the assignment of origin and the proof of adult eration of Italian, French and German wines. At first the comparabilit y of the results from three laboratories is demonstrated by the result s of interlaboratory comparison measurement and by tests of the distil lation procedures applied to the same samples. Furthermore, a close co rrelation of carbon isotope content in sugars from must and ethanol fr om the related wine could be found for samples from all countries. Usi ng the delta(13)C values of EC data bank wines from 1991 to 1993 for I taly, France and Germany, we describe and discuss the main factors of influence which are responsible for the variation of those values. By examination of spiked samples, the usefulness of the delta(13)C analys is in the detection of certain types of wine enrichment is demonstrate d; especially if the carbon isotope analysis by C-13-8 isotope ratio m ass spectrometry is employed as an additional tool for improving the s ecurity of the already officially performed determination of the site- specific hydrogen isotope content in wine ethanol by H-2-NMR.