Comtat, Maurice and Durliat, Hélène
Critical evaluation of potentiometric redox titration in enology.
(2005)
Analytica Chimica Acta, 545 (2). 173 -181 . ISSN 0003-2670
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(Document in English)
PDF (Author's version) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader 197kB |
Official URL: http://dx.doi.org/10.1016/j.aca.2005.04.084
Abstract
Measurements of the zero current potential of a platinum electrode immersed in solutions of tanins or in wines of various origins, were performed during the additions of a solution of Ti(III), or of a solution of dichlorophenolindophenol (DCPIP), in order to obtain a global indication for the resistance to oxidation of some wines. The steady state intensity–potential curves on a platinum electrode highlight the occurrence of mixed potentials between the oxidation of ethanol or catechin and the reduction of oxygen present at very low concentrations, as well as the irreversibility of the redox system Ti(IV)/Ti(III). The adsorption of various species on the platinum and the slowness of the oxidation reactions by DCPIP exclude use of potentiometric titration theory. The shape of the potential–reagent volume curves depends on the nature of the solution and on the rate of reagent introduction. Generally, due to the slowness of the oxidation reactions with DCPIP it is impossible to find a linear relationship between the volume of titrant solution necessary to reach the inflexion point of the curves and the solution composition.
Item Type: | Article |
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Additional Information: | This article is available at http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TF4-4G94HW2-7&_user=1072870&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=965294731&_rerunOrigin=google&_acct=C000043979&_version=1&_urlVersion=0&_userid=1072870&md5=bd1c785662fed0d510bd252bfc7ebc67 |
Audience (journal): | International peer-reviewed journal |
Uncontrolled Keywords: | |
Institution: | Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE) Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE) French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE) |
Laboratory name: | Laboratoire de Génie Chimique - LGC (Toulouse, France) - Procédés électrochimiques (PE) |
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Deposited On: | 23 Jul 2009 14:59 |
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