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Electrosynthesis and electrochemical characterisation of phenazine polymers for application in biosensors

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Resumo:A comparative investigation has been undertaken of the electrosynthesis and electrochemical properties of three different electroactive polymers on carbon film electrode substrates: poly(neutral red) from the phenazine dye neutral red, and poly(methylene green) and poly(methylene blue), from the corresponding phenothiazine dyes. The formation of the radical cation at different potentials and the chemical structures of the monomers both influence the electropolymerisation process of the three polyaromatic dyes. Of the three, poly(neutral red) is shown to have the best adhesion at carbon film electrodes. The influence of the electrolyte and pH on film growth and on electrochemical properties was investigated. The formal potential decreased linearly with increase in pH, in the pH range from 1 to 7 for all three polymers. The modified electrodes were also characterised by electrochemical impedance spectroscopy. The bulk and interfacial characteristics of the two phenothiazine polymers were similar and oxygen-dependent, but different to those of the phenazine polymer, poly(neutral red), which were not significantly influenced by the presence of oxygen in solution. Perspectives for use in electrochemical biosensors are indicated.
Autores principais:Barsan, Madalina M.
Outros Autores:Pinto, Edilson M.; Brett, Christopher M. A.
Assunto:Poly(neutral red) Poly(methylene green) Poly(methylene blue) Electropolymerisation Electroactive polymers
Ano:2008
País:Portugal
Tipo de documento:artigo
Tipo de acesso:acesso aberto
Instituição associada:Universidade de Coimbra
Idioma:inglês
Origem:Estudo Geral - Universidade de Coimbra
Descrição
Resumo:A comparative investigation has been undertaken of the electrosynthesis and electrochemical properties of three different electroactive polymers on carbon film electrode substrates: poly(neutral red) from the phenazine dye neutral red, and poly(methylene green) and poly(methylene blue), from the corresponding phenothiazine dyes. The formation of the radical cation at different potentials and the chemical structures of the monomers both influence the electropolymerisation process of the three polyaromatic dyes. Of the three, poly(neutral red) is shown to have the best adhesion at carbon film electrodes. The influence of the electrolyte and pH on film growth and on electrochemical properties was investigated. The formal potential decreased linearly with increase in pH, in the pH range from 1 to 7 for all three polymers. The modified electrodes were also characterised by electrochemical impedance spectroscopy. The bulk and interfacial characteristics of the two phenothiazine polymers were similar and oxygen-dependent, but different to those of the phenazine polymer, poly(neutral red), which were not significantly influenced by the presence of oxygen in solution. Perspectives for use in electrochemical biosensors are indicated.

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