Electrochemical evaluation of the a carbon-paste electrode modified with spinel manganese(IV) oxide under flow conditions for amperometric determination of lithium

Autor(es)

Raymundo-Pereira, Paulo A. ^[1] ; Martin, Cibely S. ^[1] ; Bergamini, Marcio F. ^[2] ; Bocchi, Nerilso ^[3] ; Teixeira, Marcos F. S. ^[1]

Afiliação do(s) autor(es)

^[1] Univ State Sao Paulo UNESP, Fac Sci & Technol, Dept Phys Chem & Biol, BR-19060900 Presidente Prudente, SP - Brazil

^[2] Univ Fed Parana, Dept Quim, BR-80060000 Curitiba, Parana - Brazil

^[3] Univ Fed Sao Carlos, Dept Quim, BR-13560 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Electrochimica Acta; v. 56, n. 5, p. 2552-2558, FEB 1 2011.
• Citações Web of Science: 7

Resumo

The participation of cations in redox reactions of manganese oxides provides an opportunity for development of chemical sensors for non-electroactive ions. This paper describes the amperometric determination of lithium ions using carbon-paste electrode modified with spinel manganese(IV) oxide under flow conditions. Systematic investigations were made to optimize the experimental parameters for lithium sensor by flow injection analysis. The detection was based on the measurement of anodic current generated by oxidation of Mn(III) to Mn(IV) at the surface of the electrode and consequently the lithium ions extraction into the spinel structure. An operating potential of 0.50 V (vs. Ag/AgCl/3 KCl mol/L) was exploited for amperometric monitoring. The amperometric signal was linearly dependent on the lithium ions concentration over the range 4.0 x 10(-5) to 1.0 x 10(-3) mol L(-1). The equilibrium constant of insertion/extraction of the lithium ion in the spine! structure, apparent Gibbs energy of insertion, and surface coverage of the electrode with manganese oxide, were calculated by peak charge (Q) in different concentration under flow conditions. Considering selectivity, the peak charge of the sensor was found to be linearly dependent on the ionic radius of the alkaline and earth-alkaline cations. (C) 2010 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 08/07298-7 - Estudo de filmes poliméricos de complexos à base de tiofeno-Schiff na construção de sensores eletroquímicos
• Beneficiário: Paulo Augusto Raymundo Pereira
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 09/11079-1 - Utilização de complexo de oxo-manganês-terpiridina como material eletroativo no desenvolvimento de um sensor eletroquímico
• Beneficiário: Cibely da Silva Martin Sonvesso
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica