Attributes of DC aperiodic and AC harmonic components derived from large amplitude Fourier transformed voltammetry under microfluidic control in a channel electrode

Matthews, Sinead M., Shiddiky, Muhammad J. A., Yunus, Kamran, Elton, Darrell M., Duffy, Noel W., Gu, Yungfeng, Fisher, Adrian C. and Bond, Alan M. (2012) Attributes of DC aperiodic and AC harmonic components derived from large amplitude Fourier transformed voltammetry under microfluidic control in a channel electrode. Analytical Chemistry, 84 15: 6686-6692.


Author Matthews, Sinead M.
Shiddiky, Muhammad J. A.
Yunus, Kamran
Elton, Darrell M.
Duffy, Noel W.
Gu, Yungfeng
Fisher, Adrian C.
Bond, Alan M.
Title Attributes of DC aperiodic and AC harmonic components derived from large amplitude Fourier transformed voltammetry under microfluidic control in a channel electrode
Journal name Analytical Chemistry   Check publisher's open access policy
ISSN 0003-2700
1520-6882
Publication date 2012
Sub-type Article (original research)
DOI 10.1021/ac3017554
Volume 84
Issue 15
Start page 6686
End page 6692
Total pages 7
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2013
Language eng
Abstract The flow rate dependencies of the aperiodic dc and fundamental to eighth ac harmonic components derived from large-amplitude Fourier transformed ac (FT-ac) voltammetry have been evaluated in a microfluidic flow cell containing a 25 µm gold microband electrode. For the oxidation of ferrrocene methanol ([FcMeOH]/[FcMeOH] + process) in aqueous 0.1 M KNO3 electrolyte, standard “Levich-like” dc behavior is observed for the aperiodic dc component, which enables the diffusion coefficient for FcMeOH to be obtained. In experimental studies, the first and second ac harmonic components contain contributions from the double layer capacitance current, thereby allowing details of the non-Faradaic current to be established. In contrast, the higher order harmonics and dc aperiodic component are essentially devoid of double layer capacitance contributions allowing the faradaic current dependence on flow rate to be studied. Significantly, flow rate independent data conforming to linear diffusion controlled theory are found in the sixth and higher ac harmonics at a frequency of 15 Hz and for all ac harmonics at a frequency of 90 Hz. Analysis of FT-ac voltammograms by theory based on stationary microband or planar electrode configurations confirms that stationary microband and planar electrode configuration and experimental data all converge for the higher order harmonics and establishes that the electrode kinetics are very fast (≥1 cms-1). The ability to locate from a single experiment, a dc Faradaic component displaying Levich behavior, fundamental and second harmonics that contain details of the double layer capacitance, and Faradaic ac higher order harmonic currents that are devoid of capacitance, independent of the volume flow rate and also conform closely to mass transport by planar diffusion, provides enhanced flexibility in mass transport and electrode kinetic analysis and in understanding the performance of hydrodynamic electrochemical cells and reactors.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Publication Date (Web): July 6, 2012

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
Australian Institute for Bioengineering and Nanotechnology Publications
 
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Created: Sun, 08 Jul 2012, 23:32:25 EST by Dr Muhammad J. A. Shiddiky on behalf of Aust Institute for Bioengineering & Nanotechnology