Disk electrodes central

A replaceable C disk electrode (two-electrode system) was used for end-column amperometric detection of biogenic amines. The electrode was inserted through a guide tube and was 30 5 [tm away from the capillary exit. This configuration allowed easy replacement of the electrode, especially after biofouling. The electrode was situated at a central position to maximize coulombic... 

Electrode geometry — Figure 4. Rotating disk electrode (RDE). The RDE rotates around a central axis. The solvent is pulled up vertically to the disk surface and then flung outward from the center in a radial direction... 

Fig. 2.7 Different methods for creating solution flow (see also Chapter 3) a. rotating disk electrode b. rotating cylinder electrode c. pipe stem with one test pipe as WE and two as AE d. pipe stem with one test pipe as WE and a central rod or wire as AE. In cases c and d the RE can be connected via a hole through the wall of the WE.

A RRDE consists of a central disk electrode, and a thin insulating barrier and a ring electrode, both of which are sequentially surroimding the disk electrode in the shape of concentric circle, as shown in Figure 6.1. On the RRDE, the radius of the disk, ri, and the inner radius, rz, and the outer radius, r, of the ring are the key parameters of an RRDE. 

The success of the RDE method has stimulated the development of several other rotating configurations. The RRDE is perhaps the most useful extension of the idea of the RDE. The RRDE was first developed by Frumkin and Nekrasov to detect unstable intermediates in electrode reactions. The RRDE, Fig. 4, consists of a central disk electrode surrounded by... 

Fig. 4 The RRDE consisting of a central disk electrode surrounded by a concentric insulating annulus and a concentric ring electrode.

A rotating-ring-disk electrode (RRDE) consists of a central disk of the material... 

The rotating ring-disk electrode was first proposed by Frumkin et al in 1959 [24], This system can be used two different potentials, causing a reaction in the central electrode and then another subsequent reaction at the forward ring electrode, as the transport stream shown above. The proposed modem adaptation from Fmmkin for analysis is illustrated in Figure 8. 

Fig. 7.2 Discontinuous cells used in the experiments - cell with rotating anode (left) and flowthrough cell with parallel plate electrodes (right). (1) Rotating contact, (2) electronically controlled stirrer, (3) thermostated beaker, (4) plate cathode with central hole or expanded mesh cathode, (5) rotating disk or expanded mesh anode, (6) parallel plate cell, (7) centrifugal pump, (8) stirred dark container for sampling, (9) magnetic stirrer, (10) cryostat...

Fig. 2.4. Schematic diagram of a swarm experiment to measure the ratio Dt/h-Gi is an electrode containing a small central hole and C is a collector containing a central disk At and a surrounding annulus A2.

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