The dropping mercury electrode assembly

There are various factors which affect the performance of the DME  

Three-electrode control systems are widely available in the market and there are also four-electrode systems for double working electrodes. The construction is either integral or modular. It is perfectly possible to construct the necessary electronics in-house and, in this case, modular construction is suggested as being more flexible. Operational amplifiers and other components of high quality should be used, particularly for kinetic applications. The elements of a bipotentiostat (independent control of two working electrodes) and a galvanostat are described in ref. 139. 

Three or four-electrode systems together with the use, when appropriate, of a Luggin capillary solve most of the problems of uncompensated resistance in solution. However, at times positive feedback 

Various circuits have been described to measure collection efficiencies based on galvanostatic control of the upstream electrode with the downstream electrode being held at the limiting current for the reaction taking place there. It is also possible to measure N0 by a potentiostatic shielding experiment. For, an irreversible electrode reaction, measurement of N0 in these two different ways will, in principle, give different results if the upstream electrode is not uniformly accessible. 

Analogue control of the electrode potential or current is achieved by a function generator there are now very expensive waveform generators on the market which enable any potential on current waveform to be applied. 

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