Stripping Voltammetry at Microdisk Electrode Arrays: Theory

Abstract

Anodic stripping voltammetry (ASV) is an extremely powerful tool for detection of metal ions in solution through a two step process of preconcentration of the metal at the electrode surface, followed by electrodissolution. The second phase produces an electroanalytical response proportional to the amount of material deposited in the first phase. This paper utilizes theory to explore the electrochemical signals produced when considering ASV at a microelectrode or ultramicroelectrode arrays. The theory outlined is applicable mostly to thin mercury film absorption and metal adsorption.

Dual-microdisk electrodes in transient generator–collector mode: Experiment and theory

“…Baur et al assumed a semi-infinite boundary at a distance of 12 radii divided by the diffusional distance moved each step -for example, where a semi-infinite boundary is set at 60 diffusional distances from the electrode surface, and thus after 60 steps, an element could have hit the electrode, then a side boundary, and re-enter the other side, much like an array, despite the simulation being run over 10,000 steps. This is in contrast to common simulation practice, where a diffusion domain size proportional to the experimental time has been extensively used successfully [43,[54][55][56][57][58][59] and is known to sufficiently exceed the diffusion layer in all cases [60]. Also of note, is the method by which Brownian diffusion was modelled -a pseudo pyramidal diffusion from the electrode is observed due to tri-axial random movement being considered, rather than an easily implementable spherical diffusion model.…”

Using graphics processors to facilitate explicit digital electrochemical simulation: Theory of elliptical disc electrodes

“…Using grid definitions previously published [35], and the substitutions given in Table 3, Eq. (7) expands explicitly by finite differences to give Eq.…”

“…As a result, one-quarter of the ellipse is simulated only, and appropriate boundary conditions (Section 2.2) are applied. Mesh generation for this work combines the expanding mesh principles devised by Gavaghan [4] and ourselves previously [35] combined with those used by Streeter et al [36] to deal with spherical electrodes. To mimic the curvature of an elliptical electrode, high density rectangular grids are used over the electrode surface in the X-Y plane, and Gavaghan-style expanding grids thereafter.…”

Electrochemical random-walk theory

“…The boundaries set away from the electrode are semi-infinite boundaries, positioned sufficiently far away from the electrode to exceed the diffusion layer. This has been shown to be a distance from the electrode of six times the square root of the maximum dimensionless time reached by the simulation, 6 ffiffiffiffiffiffiffiffiffi ffi s max p , by Gavaghan [39], and has been used extensively in previous work [6,15,40]. Eqs.…”