Theory and practice of electrochemical titrations with dual microband electrodes

Rajantie, H.; Strutwolf, Jörg; Williams, David E.

doi:10.1016/s0022-0728(00)00426-5

Cited by 42 publications

(48 citation statements)

References 22 publications

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“…During the time stepping process diffusion in each space direction is then treated simultaneously implicit. For the simulation of two dimensional electrochemical diffusion problems this approach has been used employing the CrankNicholson [33], BDF [16,18,32], Rosenbrock [34] and extrapolation [18] (note that extrapolation can also be performed with only one space direction treated implicitly per time sub-step, as has been applied to microband [35], double band [36] and interdigitated array electrode simulation [28]). A disadvantage of taking all space directions implicitly during the time increment is the amount of computer memory and cpu-time necessary for solving the system of (N X þ 1) Â (N Y þ 1) equations during each time step, when the number of grid points in the X and Y direction, N X and N Y becomes high and small time steps are used.…”

Section: The Douglas-gunn Adi Schemementioning

confidence: 99%

Computational Study of Chronoamperometry at Rectangular Microelectrodes

Strutwolf

2005

Electroanalysis

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Three (space) dimensional diffusion to a rectangular microelectrode of length l and width w, embedded in an infinite coplanar insulator is simulated with boundary conditions for a chronoamperometric experiment. An alternating direction implicit finite difference method (Douglas-Gunn algorithm) utilizing a problem adapted grid is used to solve the diffusion equation. Current transients are computed for different values of the dimensionless length parameter L ¼ l/w, starting with L ¼ 1, i.e., a square electrode. Edge effects at the four sides of the rectangular electrode as well as the vertex effect contribute to the total current. With increasing L the transients approach the behavior of a microband electrode transient, where diffusion is essentially two dimensional. The breakdown of the two dimensional diffusion approach with decreasing values of L is analyzed and quantified. This serves as a guideline for analyzing transients measured with electrodes where the condition l » w is not fulfilled.

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Section: The Douglas-gunn Adi Schemementioning

confidence: 99%

Computational Study of Chronoamperometry at Rectangular Microelectrodes

Strutwolf

2005

Electroanalysis

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“…Nekresov's original rotating ring disc 2 (also extensively studied by Albery and coworkers ), wall jet ring discs, 27-29 dual band electrodes (used both in static solution [30][31][32][33] and hydrodynamic electrochemistry in a flow cell [34][35][36][37] ), dual discs [38][39][40] and hemispheres, [41][42][43][44] and ring-or planerecessed disc electrodes. [45][46][47] The uses of collector-generator systems have proved at least as varied as their geometries!…”

Section: Introductionmentioning

confidence: 99%

“…al. [30][31][32] in electrochemical titration experiments, where a species which has been electrogenerated at the generator electrode undergoes a reaction with a target analyte in solution. Any surviving electrogenerated species is then detected at the collector electrode:…”

Section: Introductionmentioning

confidence: 99%

Dual band electrodes in generator–collector mode: Simultaneous measurement of two species

Barnes

Lewis

Dale

et al. 2013

Journal of Electroanalytical Chemistry

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A computational model for the simulation of a double band collector-generator experiment is applied to the situation where two electrochemical reactions occur concurrently. It is shown that chronoamperometric measurements can be used to take advantage of differences in diffusion coefficients to measure the concentrations of both electroactive species simultaneously, by measuring the time at which the collection efficiency reaches a specific value. The separation of the electrodes is shown to not affect the sensitivity of the method (in terms of percentage changes in the measured time to reach the specified collection efficiency), but wider gaps can provide a greater range of (larger) absolute values of this characteristic time. It is also shown that measuring the time taken to reach smaller collection efficiencies can allow for the detection of smaller amounts of whichever species diffuses faster. The case of a system containing both ascorbic acid and dopamine in water is used to exemplify the method, and it is shown that mole fractions of ascorbic acid between 0.055 and 0.96 can, in principle, be accurately measured.

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“…Conformal maps for modelling the collector-generator behavior as a function of the widthto-gap ratio for a double [2] and a triple band configuration [3] have shown a good agreement between models and experimental data. Later, the application-specific modelling based on conformal mapping was successfully adopted for simulating the current distribution at dual microband electrodes and their efficiency in electrochemical titrations [4,5]. A diffusion model was also exploited for characterizing the flow rates in microchannels [6].…”

Section: Introductionmentioning

confidence: 99%

Theoretical treatment and computer simulation of microelectrode arrays

Morf¹,

Koudelka‐Hep²,

Rooij³

2006

Journal of Electroanalytical Chemistry

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New relations for and interrelations between the current responses of different microelectrode arrays are presented. Interdigitated microelectrode arrays (IDAs: alternating cathodes and anodes) and uniform microband electrode arrays (MEAs: only cathodes or anodes) are treated, and miniaturized systems with planar band electrodes or hemicylinder electrodes are discussed. A common basis was found for the specific response characteristics of IDAs and MEAs. The theoretical expressions were verified by results from computer modelling. The numerical simulations made use of finite-element procedures to evaluate steady-state and time-dependent mass fluxes and concentration profiles of electroactive species at the surfaces of different microelectrode arrays. It was shown that the response behavior of a given array can be exactly predicted from the current data of other arrays.

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Theory and practice of electrochemical titrations with dual microband electrodes

Cited by 42 publications

References 22 publications

Computational Study of Chronoamperometry at Rectangular Microelectrodes

Computational Study of Chronoamperometry at Rectangular Microelectrodes

Dual band electrodes in generator–collector mode: Simultaneous measurement of two species

Theoretical treatment and computer simulation of microelectrode arrays

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