Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance upgrade on Thursday 4th of May 2017 from 8.00am to 9.00am (BST).

During this time our websites will be offline temporarily. If you have any questions please use the feedback button on this page. We apologise for any inconvenience this might cause and thank you for your patience.

Issue 6, 1996
Previous Article Next Article

Reaction/diffusion with Michaelis–Menten kinetics in electroactive polymer films. Part 1. The steady-state amperometric response


The theoretical analysis of the steady-state amperometric response for a polymer-modified electrode system whcih exhibits Michaelis–Menten kinetics is discussed. In particular, the interplay between substrate diffusion within the polymer matrix and substrate reaction at the catalytic polymer sites is examined. A non-linear reaction/diffusion equation describing the substrate transport and reaction kinetics within the film is formulated and approximate analytical solutions for the substrate concentration profiles and corresponding current responses are developed. Four distinct limiting cases are developed and are represented schematically in a kinetic case diagram. The theoretical analysis is extended to consider the complicating situation of substrate diffusion in the Nernst diffusion layer adjacent to the polymer film. The allied problem of the response of a potentiometric sensor exhibiting Michaelis–Menten kinetics is also examined. The theoretical model developed in the paper is validated by examining the electro-oxidation of dopamine, adrenaline and noradrenaline at surfactant-doped polypyrrole-modified electrodes. Good agreement between the amperometric current response predicted from the theoretical model and the current response obtained experimentally from batch amperometry is obtained. Non-linear least-squares analysis of the batch amperometric data in tandem with the theoretical expression derived for the steady-state current response produces reasonable values for the Michaelis constant, Km, the catalytic rate constant, Kc, and the substrate diffusion coefficient, Ds, for each of the three catecholamine substrates examined.

Back to tab navigation
Please wait while Download options loads

Article type: Paper
DOI: 10.1039/AN9962100715
Citation: Analyst, 1996,121, 715-731
  •   Request permissions

    Reaction/diffusion with Michaelis–Menten kinetics in electroactive polymer films. Part 1. The steady-state amperometric response

    M. E. G. Lyons, J. C. Greer, C. A. Fitzgerald, T. Bannon and P. N. Barlett, Analyst, 1996, 121, 715
    DOI: 10.1039/AN9962100715

Search articles by author