Redox Mechanisms of Nodularin and Chemically Degraded Nodularin |
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| Authors: | Paulina V F Santos Ilanna C Lopes Victor C Diculescu Mário César U de Araújo Ana Maria Oliveira‐Brett |
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| Institution: | 1. Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004‐535 Coimbra, Portugal, Tel/fax: +351‐239‐835295;2. Departamento de Química, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, 58059‐900, Paraíba, Brasil |
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| Abstract: | The electrochemical behaviour of Nodularin (NOD), a hepatotoxic cyclic pentapeptide, was studied at a glassy carbon electrode. NOD electrochemical oxidation is an irreversible, pH‐independent process, involving the transfer of one electron. Upon incubation in different pH electrolytes, chemical degradation of NOD was electrochemically detected by the appearance of a new oxidation peak. The chemically degraded NOD (cdNOD), undergoes an irreversible, pH‐dependent oxidation, and its redox products are reversibly oxidised. The charge transfer properties of cdNOD as well as of its redox metabolites were investigated. Mechanisms for NOD oxidation, NOD chemical degradation and oxidation of cdNOD and its metabolites were proposed. |
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| Keywords: | Nodularin Cyanobacteria Degradation products Oxidation pH effect |
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