A new rapid and simple method to determine the kinetics of electrode reactions of biologically relevant compounds from the half-peak width of the square-wave voltammograms

Gulaboski, Rubin and Lovrić, Milivoj and Mirceski, Valentin and Bogeski, Ivan and Hoth, Markus (2008) A new rapid and simple method to determine the kinetics of electrode reactions of biologically relevant compounds from the half-peak width of the square-wave voltammograms. Biophysical Chemistry, 138 (3). pp. 130-137. ISSN 03014622

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Abstract

A new method is introduced to determine the kinetic parameters of electron transfer reactions of biologically
important compounds, based on the measurements of the half-peak width (ΔEp/2) of the square-wave
voltammograms. A simple surface (diffusionless) redox reaction, and a simple electrode reaction occurring
from dissolved state are considered as model systems. In the region of quasireversible electron transfer,
the half-peak widths of theoretical square-wave voltammograms are linear functions of the logarithm of the
dimensionless kinetic parameter ln(K) that characterizes the rate of the electron transfer reaction. The
dimensionless kinetic parameter K is defined as K=ks(fD)−0.5 for the redox reaction taking place from
dissolved state, whereas for the surface redox reaction K is defined as K=ks/f (ks is the standard rate constant
of electron transfer, f is the SW frequency, and D is the diffusion coefficient). A set of linear regression
equations for the dependences ΔEp/2 vs. ln(K) are derived, which can be used for rapid and precise
determination of the charge-transfer kinetic parameters. The estimated values for the standard rate
constants of various biologically relevant redox systems using this approach are in very good agreement with
the experimental values determined by other square-wave voltammetric methods. The square-wave
voltammetric half-peak width method can be used as a simple and reliable alternative to other voltammetric
methods developed for the kinetic characterization of electron transfer rates.

Item Type: Article
Uncontrolled Keywords: square-wave voltammetry, mathematical modeling, kinetic parameters, half-peak width, standard rate constant of electron transfer, electron transfer coefficient, amperometry
Subjects: Natural sciences > Chemical sciences
Divisions: Faculty of Agriculture
Depositing User: Rubin Gulaboski
Date Deposited: 31 Oct 2012 10:26
Last Modified: 31 Oct 2012 10:26
URI: https://eprints.ugd.edu.mk/id/eprint/134

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