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Electrochemical methods for autonomous monitoring of chemicals (oxygen and phosphate) in seawater: Application to the Oxygen Minimum Zone

Justyna Elzbieta Jonca 1
1 DYNBIO LEGOS
LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
Abstract : Developing new sensors for improving our understanding of the coupled biogeochemical cycles constitutes an immense challenge. Electrochemistry provides promising reagentless methods by going further in miniaturization, decreasing the response time and energy requirements and thus increasing our observing capacities in the ocean. This study is focused on phosphate and oxygen, two key compounds of the marine ecosystems. Improvement of the amperometric STOX sensor for ultra-low oxygen detection in seawater is presented. The improvement was achieved by changing sensor construction and preliminary studies showed higher sensitivity and faster response time. A novel electrochemical method for phosphate detection was developed. The method is based on anodic oxidation of molybdenum in seawater in order to form the phosphomolybdic complex, electrochemically detectable by means of amperometry or voltammetry. Thanks to special construction of an electrochemical cell including specific membrane technology, the method does not require addition of reagents and is free from silicate interferences. The method was tested during Pelagico 1011- 12-BIC OLAYA cruise offshore Peru in 2010. The Peruvian water masses analysis was also performed using data collected during this cruise
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Justyna Elzbieta Jonca. Electrochemical methods for autonomous monitoring of chemicals (oxygen and phosphate) in seawater: Application to the Oxygen Minimum Zone. Analytical chemistry. Université Paul Sabatier - Toulouse III, 2012. English. ⟨tel-00776773⟩

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