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Silicate determination in sea water: toward a reagentless electrochemical method

Comtat, Maurice and Garçon, Véronique and Lacombe, Marielle and Le Bris, Nadine and Oriol, Louise and Provost, Christine and Thouron, Danièle and Sudre, Joel Silicate determination in sea water: toward a reagentless electrochemical method. (2007) Marine Chemistry, vol. 106 (n° 3-4). pp. 489-497 . ISSN 0304-4203

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Official URL: http://dx.doi.org/10.1016/j.marchem.2007.05.002

Abstract

ilicate has been determined in sea water by four different electrochemical methods based on the detection of the silicomolybdic complex formed in acidic media by the reaction between silicate and molybdenum salts. The first two methods are based on the addition of molybdate and protons in a seawater sample in an electrochemical cell. Cyclic voltammetry presents two reduction and two oxidation peaks giving four values of the concentration and therefore increasing the precision. Then chronoamperometry is performed on an electrode held at a constant potential. A semi-autonomous method has been developed based on the electrochemical anodic oxidation of molybdenum, the complexation of the oxidation product with silicate and the detection of the complex by cyclic voltammetry. This method is tested and compared with the classical colorimetric one during ANT XXIII/3 cruise across Drake Passage (January–February 2006). The detection limit is 1 μM and the deviation between both methods is less than 3% for concentrations higher than 10 μM. Finally a complete reagentless method with a precision of 2.6% is described based on the simultaneous formation of the molybdenum salt and protons in a divided electrochemical cell. This latter method should be very useful for developing a reagentless sensor suitable for long term in situ deployments on oceanic biogeochemical observatories.

Item Type:Article
Additional Information:This article is available at http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VC2-4NTB99N-1&_user=1072870&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=965075303&_rerunOrigin=google&_acct=C000043979&_version=1&_urlVersion=0&_userid=1072870&md5=54754a45ed0044928e3ddb7d268150eb
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
French research institutions > Institut Français de Recherche pour l'Exploitation de la MER - IFREMER
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
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Deposited By: Guylène Abadie
Deposited On:23 Jul 2009 09:51

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