Electrochemical Multichannel-Microelectrodes 電化學多通道微電極

Thomas RECORDING electrochemical disc micro-electrodes were originally designed for SECM (Scanning ElectroChemical Microscopy), but they are also suitable as working electrodes for other electrochemical applications like voltammetry or amperometry.

The electrodes are based on unique multicore metal fiber of platinumtungsten alloy, insulated with quartz glass.

Figure 1 Tip of a Thomas 7 channel microelectrode for electrochemical appliactions (tip shape D, other tip shapes are available , see figure 2 and pdf product brochure below). The 7 metal wires (alloy of 95% platinum and 5% tungsten) are insulated from each other by quartz glass.

Figure 2 For the 7 channel microelectrode the tip shapes C and D are available, for the 4 channel version of the microelectrode tip shapes A-D are available

A special manufacturing process guarantees a highly centered metal core within the glass insulation and a high reproducibility of the tip geometry. Thomas multicore fibers are produced in a circular alignment, with one central metal core and three or six surrounding electrode wires.
 
Thomas multicore-microelectrodes may serve as quasi ring-disk-electrodes with the central core as disk and the surrounding six cores hot-wired as ring electrode (see figure 3).

Figure 3 Cross section of a 7 channel microelectrode for electrochemical applications.

These electrodes combine the stationary diffusion field of an ultramicroelectrode with the concentric arrangement of a ring-disk electrode, serving as micro-analogon to the rotating ring-disk electrode. With these unique electrodes it is possible to run a SECM in generationcollection mode without the need of a conducting sample, and without an influence of scan direction. Another possible application is kinetic research in small volumes, which is appreciable for analysis of expensive or rare substances like natural products or noble metal compounds. 
 
The use of Thomas seven-core electrodes as micro ring-disk electrodes for SECM was first introduced by Heinze et. al. in 2002, followed by a comparison of experimental data with theoretical simulations by BEM-Method. They were also successfully applied as functionalized SECM-Sensors for active site mapping on nafion-membranes for fuel cells.
 
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