Microband Arrays

Actually, there are reports on transforming the negative effect of separation electric field into new detection approaches. A potentiostat-less detection scheme for amperometric detection in CE based on the use of microband array electrodes situated in the CE electric field has been proposed [53] as well as the use of an indirect amperometric detection with a carbon fibre in-channel configuration [54]. In this case, the potential difference induced by the CE separation electric field produces a change in the reduction potential of oxygen, which can be used to determine nonelectroactive analytes. 

Apart from this change in boundary condition, the simulation space for a microband array is exactly the same as for the single microband, depicted in Figure 9.8. As with the microdisc array, it is necessary to alter the spatial grid in the X-direction so that there is a high concentration of spatial points at this outer boundary to ensure accurate simulation. 

Interdigitated microband arrays (IDAs) are another example of an electrode system with spatially variant electrode kinetics. The sj tem consists of two... 

The simulation model is similar to that used for the microband array but with altered surface z = 0) boundary conditions and an x-grid spacing modified to take account of the newly introduced singularity at x = d — Xe-The surface boundary conditions are different for each species and vary with X according to the following ... 

Cooper JA, Compton RG (1998) Photoelectrochemical reduction of p-bromonitrobenzene mechanistic discrimination via channel microband array voltammetry. Electroanalysis 10 (17) 1182-1187. doi 10.1002/(sici)1521-4109(199811)10 17<1182 aid-elanll82>3.0.co 2-k... 

J.M. Slater and E.J. Watt, On-chip microband array electrochemical detector for use in capillary electrophoresis. Analyst, 1994, 119, 2303-2307. 

Tezuka, Y., and Aoki, K., Direct demonstration of the propagation theory of a conductive zone in a polypyrrole film by observing temporal and spatial variations of potentials at addressable microband array electrodes, J. Electroanal. Chem., 273, 161-168 (1989). 

Fig. 7 (A) SEM image of the 1.5 imn x 1.5 mm interdigitated gold microband array electrode with 7 jm gold bands separated by 13 pm gaps. (B) Schematic drawing of a PPP droplet containing Co(II)phthalocyanine situated between generator and collector on the gold band array and immersed into aqueous electrolyte solution. Oxidation at the generator electrode (in the triple phase boundary reaction zone) causes anion transfer from the aqueous into the organic phase and reduction at the collector electrode causes transfer of the anion back into the aqueous phase (taken from ref 50).

Fig. 2.18 The most important geometries of microelectrodes and microelectrode arrays a microdisk b microring c microdisk array (a composite electrode) d lithographically produced microband array e microband f single fibre (microcylinder) g microsphere h microhemisphere i fibre array j interdigitated array. Image reproduced with permission from Ref. [7], copyright 2000 International Union of Pure and Applied Chemistry...

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