Elemental characterization of sparkling wine and cork stoppers

The variations of the elemental concentrations in sparkling white wine and respective cork stoppers throughout 18 months of storage time were determined with the PIXE (Particle-Induced X-ray Emission) technique. Three portions of the cork stoppers were analyzed: the top part (external layer), the inner part (bulk layer) and the bottom layer (which was in contact with the sparkling wine). Elements such as Na, Mg, Si, P, S, Cl, K, Ca, Mn, Fe, Zn and Rb were determined for both cork stoppers and sparkling wine samples. Similar concentrations of Si, P, S, Cl and Ca were found in the external and bottom layers of the corks. Distinct behaviors of the changes in the elemental concentrations as a function of the time were observed for cork stoppers and sparkling wines. The concentrations of Mg, S, K, Ca, Cu, Sr and Ba increased in the bottom layer of the cork as a function of storage time. On the other hand, concentrations of Al, Si, Cl, Ti, Zn and Br proved to be invariant, while the concentrations of P and Fe showed a slight decrease. Concerning the sparkling wine, an increasing trend of elemental concentrations was observed for most elements throughout the storage time. A diffusion mechanism of elements in the cork and the role of the secondary fermentation in the bottle are discussed.