Characterization of the geographic origin of Bordeaux wines by a combined use of isotopic and trace element measurements

The authentication potential of combined isotopic and trace element analyse s of wines from a relatively restricted geographical area has been estimate d for the Bordeaux region in France. The natural abundance isotopic ratios of hydrogen, oxygen, and carbon, from water and ethanol extracted from the wine enable some distinctions between subregions. However the SNIF-NMR (Sit e-specific Natural Isotope Fractionation studied by NMR) and IRMS (Isotope Ratio Mass Spectrometry) parameters, which are subject to climatic influenc es, are usually more efficient for characterizing the year of production of a given appellation than for distinguishing different appellations. In thi s respect, significant enhancement of the authentication performances is ac hieved by considering selected trace elements which are specific of the soi l. Appropriate isotopic and trace element databases enable specific subregi ons, even of small size, to be characterized by typical analytical patterns . It is then possible, as illustrated in the case of Pauillac wines, to det ermine whether commercial samples meet the quality criteria required by fam ous appellations.