The Compton-Waller Cell

FIGURE 21. The Compton-Waller cell. A, PTFE annulus B, PTFE insulation C, electrode (mercury-plated copper) D, copper E, TEqh cylindrical cavity F, PTFE sheath G, precision-bore silica tubing. The numbers represent the dimensions in millimeters. 

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Fig. 22. The sensitivity of the Compton-Waller cell as a function of distance along its axis. The line drawn represents the theoretical sin2 behaviour.

Fig. 24. Limiting current-flow rate behaviour for the reduction of fluorescein (pH 13) at the Compton-Waller cell.

Figure 8.5 Schematic representation of a typical EPR cell - in this case, the Compton-Waller flow cell - used for in situ spectroelectrochemistry. The working electrode is placed outside of the cavity of the EPR spectrometer, with the counter elecUode being normally an SCE or AgCl,Ag . The working electrode is a flat polished plate of platinum, positioned parallel to the direction of the electric field. Reproduced from Compton, R. G. and Waller, A. M., Comprehensive Chemical Kinetics, Vol. 29, p. 173, Copyright (1989), with permission from Elsevier Science.

Cell Design Waller and Compton [85] effectively mimicked the Allendo-erfer coaxial design vide supra), whilst simultaneously maintaining the mathematically well-defined laminar flow of the channel flow cell. This improved cell for electrochemical EPR [85] allowed an improvement in the channel cell regarding lifetimes of radicals amenable to study, whilst retaining the hydrodynamic flow that is essential for the investigation of electrode reaction mechanisms. 

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