| Summary: | Wine samples fermented up to a maximum of 345 days have been monitored, and concentrations of Zn, Cu, Mn and Fe have been measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Results show a decrease throughout the fermentation time for Cu and Fe concentrations while Zn and Mn concentrations remained stable for the same period of time. Electrochemical techniques were used to perform complexation studies from pH 4 buffered solutions (pH of the wine) containing a model ligand, catechin, to prove the applicability of differential pulse anodic stripping voltammetry (DPASV) technique to study samples conditioned at the above mentioned pH. The stoichiometry found for the catechin:metal complexes was 1:1 both for Zn and Cu. The electrochemical behaviour of a diluted wine sample subjected to identical experimental conditions as those applied to the model ligand solutions, suggested that the majority of the natural ligands present in wine, able to complex Zn and Cu, have a very similar structure to that of catechin.
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