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 analysis of wine ethanol for the assignment of origin and the proof of adulteration of Italian, French and German wines. At first the comparability of the results from three laboratories is demonstrated by the results of interlaboratory comparison measurement and by tests of the distillation procedures applied to the same samples. Furthermore, a close correlation of carbon isotope content in sugars from must and ethanol from the related wine could be found for samples from all countries. Using the delta(13)C values of EC data bank wines from 1991 to 1993 for Italy, 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 analysis in the detection of certain types of wine enrichment is demonstrated; especially if the carbon isotope analysis by C-13-8 isotope ratio mass spectrometry is employed as an additional tool for improving the security of the already officially performed determination of the site-specific hydrogen isotope content in wine ethanol by H-2-NMR.