Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/34728
標題: Square-wave voltammetric determination and ac impedance study of dopamine on preanodized perfluorosulfonated ionomer-coated glassy carbon electrodes
作者: Zen, J.M.
曾志明
Ilangovan, G.
Jou, J.J.
關鍵字: chemically-modified electrode;transmission-line model;differential;capacitance;charge propagation;pyrolytic-graphite;brain-tissue;uric-acid;nafion;diffusion;films
Project: Analytical Chemistry
期刊/報告no:: Analytical Chemistry, Volume 71, Issue 14, Page(s) 2797-2805.
摘要: 
Preanodization of the Nafion-coated glassy carbon electrode (NCGCE) results in a large increase in the square-wave voltammetric peak current of dopamine (DA) with an excellent detection limit cb 4.7 nM (S/N = 3) in pH 7.4 phosphate buffer solution. Chronocoulometry showed an increase in double-layer charge and the adsorption control of charge transfer. The surface coverage was calculated to be 3.1 x 10(-10) mol/cm(2), reminiscent of a monolayer coverage. The cause for such an increase in peak current on preanodization is unraveled using impedance measurements. The result reveals that the bulk resistance of Nafion is reduced progressively, and hence more solvent is found to permeate into the NCGCE, at more anodic preanodization potentials, The increase in the fraction of ion clusters in the bulk polymer exposing more SO3- and thus more cationic DA is exchanged to maintain the electroneutrality, The GCE/Nafion interfacial charge also increased with the preanodization potential due to the induction of >C=O on the GCE surface. The interaction of the >C=O with DA, possibly through hydrogen bonding, is envisaged to further increase the sensitivity in DB detection.
URI: http://hdl.handle.net/11455/34728
ISSN: 0003-2700
DOI: 10.1021/ac981009a
Appears in Collections:化學系所

Show full item record
 

Google ScholarTM

Check

Altmetric

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.