Silicate electrochemical measurements in seawater: Chemical and analytical aspects towards a reagentless sensor

Marielle Lacombe (1) , Veronique Garçon (1) , Danièle Thouron (1) , Nadine Le Bris (2) , Maurice Comtat (3)

1 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
2 EEP - Etudes des Ecosystèmes Profonds
3 LGC - Laboratoire de Génie Chimique

From the study of molybdenum oxidation in aqueous solutions we developed a semi-autonomous method to detect silicate in aqueous samples. Molybdenum oxidation was used to form molybdate in acidic media. The silicomolybdic complex formed with silicate is detectable by amperometry or cyclic voltammetry. The new electrochemical method is in good agreement with the method conventionally used for environmental water silicate analysis. In the second stage, a completely reagentless method was developed using molybdate and proton produced during molybdenum oxidation. Reproducibility tests show a precision of 2.6% for a concentration of 100 [mu]mol L-1. This new method will be very suitable for the development of new autonomous silicate sensors easy to handle and without reagents. In this paper we present the analytical and chemical aspects necessary for a complete documentation of the method before the development of a new reagentless sensor.

Mots clés: Amperometry; Cyclic voltammetry; Molybdenum; Reagentless; Silicate

Domaines: Océan, Atmosphère

Marielle Lacombe, Veronique Garçon, Danièle Thouron, Nadine Le Bris, Maurice Comtat. Silicate electrochemical measurements in seawater: Chemical and analytical aspects towards a reagentless sensor. Talanta, 2008, 77 (2), pp.744-750. ⟨10.1016/j.talanta.2008.07.023⟩. ⟨hal-00402513⟩