ISSN:
1040-0397
Keywords:
Polyaniline
;
Biosensor
;
Benzoquinone
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The enzyme-mediator-conducting polymer model provides a convenient charge transporting immobilization matrix for redox enzymes in potential biosensor constructions. This study considers the charge transport mechanism in the benzoquinone (Q)-polyaniline (Pani) system. An enhanced current can be obtained on Pani, compared with Pt, using Q as enzyme mediator. Two-electron redox pathways are available for the Q/H2Q (hydroquinone) system, but the kinetics limit this conversion. On Pt, one-electron equivalent is estimated. On Pani-modified electrodes, reduction of Q on Pani is a nearly reversible two-electron process at stationary electrodes at low pH. At rotating electrodes, the initial reaction occurs at the surface of the polymer at pH 1.1, but the second electron transfer is prevented by loss of the intermediate from the surface before it can migrate into the film. At stationary electrodes, the H2Q product is stabilized, possibly by the formation of a charge-compensating complex between the H2Q anion/radical and the polymer. At higher pH, charge transfer through the polymer is slow and no reduction of Q occurs on the outside of the film, instead occurring in a layer at the electrode limited by the exchange kinetics there. Promotion of the two-electron pathways on Pani is proposed as the source of current enhancement when Q is employed as an enzyme mediator.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elan.1140050504
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