Theoretical Contribution Towards Understanding Specific Behaviour of “Simple” Protein‐film Reactions in Square‐wave Voltammetry

Gulaboski, Rubin (2018) Theoretical Contribution Towards Understanding Specific Behaviour of “Simple” Protein‐film Reactions in Square‐wave Voltammetry. Electroanalysis, 30. pp. 1-10. ISSN 1040-0397

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Surface reactions of uniformly adsorbed redox
molecules at working electrode surface are seen as
adequate models to studying chemical reactivity of many
lipophilic enzymes. When considered under pulse voltammetric
techniques, these systems show several uncommon
features, whose origin is still not completely clear. The
phenomena of “quasireverible maximum”, “splitting” of
the net peak in square-wave voltammetry, and the very
steep descent of Faradaic currents of simple surface redox
reactions exhibiting fast electron transfer are just some of
the features that make these systems quite interesting for
further elaborations. In this work, we present a set of
theoretical calculations under conditions of square-wave
voltammetry in a way to try to explain some of aforementioned phenomena. The major goal of our work is to get insight to some voltammetric and chrono-amperometric
features of two considered surface reactions, i.e. (1) the
“simple” surface redox reaction, and (2) surface redox
reaction coupled to follow-up irreversible chemical reaction
of electrochemically generated redox species (or
surface ECirr). We focus on the role of created Red(ads)
(here in the reduction pulses only) to the current
components of calculated square-wave voltammograms
exhibiting fast electrode reaction. We show that the
irreversible chemical removal of electrochemically generated
Red(ads) species, created in the potential pulses
where half-reaction of reduction Ox(ads)+ne- ---> Red(
ads) is “defined” to take place, causes significant
increase of all square-wave current components. The
results presented in this work show how complex the
chrono-amperometric features of surface redox reactions
under pulse voltammetric conditions might be. In addition,
we point out that both half reactions of a given
simple surface redox process can occur, at both, “only
reduction” and “only oxidation” potential pulses in
square-wave voltammetry. This, in turn, contributes to the
occurrence of many phenomena observed in simple
protein-film voltammetry reactions. The effects of chemical
reaction rate to the features of calculated squarewave
voltammograms of surface ECirr systems with fast
electrode reaction are reported for the first time in this

Item Type: Article
Subjects: Medical and Health Sciences > Basic medicine
Natural sciences > Biological sciences
Natural sciences > Chemical sciences
Natural sciences > Computer and information sciences
Natural sciences > Matematics
Natural sciences > Physical sciences
Divisions: Faculty of Medical Science
Depositing User: Rubin Gulaboski
Date Deposited: 13 Dec 2018 11:37
Last Modified: 13 Dec 2018 11:38

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