Electrochemical Properties of the Oxo‐Manganese‐Phenanthroline Complex Immobilized on Ion‐Exchange Polymeric Film and Its Application as Biomimetic Sensor for Sulfite Ions |
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Authors: | Wesley B S Machini Marcos F S Teixeira |
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Institution: | Department of Physics, Chemistry and Biology, Faculty of Science and Technology, Sao Paulo State University (UNESP), Presidente Prudente, SP, Brazil |
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Abstract: | A biomimetic sensor containing the oxo‐bridged dinuclear manganese‐phenanthroline complex incorporated into a cation‐exchange polymeric film deposited onto glassy carbon electrode for detection of sulfite was studied. Cyclic voltammetry at the modified electrode in universal buffer showed a two electron oxidation/reduction of the couple MnIV(μ‐O)2MnIV/MnIII(μ‐O)2MnIII. The sensor exhibited electrocatalytic property toward sulfite oxidation with a decrease of the overpotential of 450 mV compared with the glassy carbon electrode. A plot of the anodic current versus the sulfite concentration for potential fixed (+0.15 V vs. SCE) at the sensor was linear in the 4.99×10?7 to 2.49×10?6 mol L?1 concentration range and the concentration limit was 1.33×10?7 mol L?1. The mediated mechanism was derived by Michaelis? Menten kinetics. The calculated kinetics values were Michaelis? Menten rate constant= =1.33 µmol L?1, catalytic rate constant=6.06×10?3 s?1 and heterogeneous electro‐chemical rate constant=3.61×10?5 cm s?1. |
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Keywords: | Biomimetic oxo‐manganese complex Biomimetic activity Electrocatalytic sulfite sensor |
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