Mercury jet electrode

June 24, 1922, Pfsek, then Czechoslovakia - May 30, 1994, Prague, Czech Republic) Professor of physical chemistry at Charles University, leading scientific worker of the Polarographic Institute, Prague. Koryta studied processes at the mercury jet electrode [i-ii], the electrochemical behavior of complex compounds [iii], and the effect of adsorption of electroinactive compounds on electrode processes [iv]. Later he concentrated on processes at the interface of immiscible electrolyte solutions (- interface between two immiscible electrolyte solutions, ion transfer at liquid-liquid interfaces) [v, vi]. He co-authored a textbook on electrochemistry ([vii]), which was translated into several languages. 

Streaming mercury electrode (mercury jet electrode) — Figure. In... 

Mercury cell process alkali chloride electrolysis Mercury jet electrode streaming mercury electrode... 

A. G. Fogg and A. M. Summan, Simple Wall-Jet Detector Cell Holding Either a Solid Electrode or a Sessile Mercury-Drop Electrode and an Illustration of Its Use in the Oxidative and Reductive Flow Injection Voltammetric Determination of Food Colouring Matters. Analyst, 109 (1984) 1029. 

This arrangement is in fact a refinement to an in situ cell designed by Scholz and coworkers Fig. 29 [93], in which a jet of electrolyte impinges on a wire or mercury drop electrode. The modifications by Compton and coworkers [98] allow for controlled convection and enhancement of its sensitivity towards unstable radicals. The cell itself consists of a silica tube with a mercury working electrode placed at one end. Solution flows into the cell via the steel jet so that it impinges normally and centrally on the electrode surface. 

Fig. 30 The flow pattern between the jet and the mercury working electrode under thin-layer conditions.

In the opinion of Pitzer (28), this experimental procedure, with improvements in sensitivity, may provide useful data in the future for the thermodynamic functions of single ionic species. That this goal may be achieved in the near future is suggested by the study of Farrell and McTigue (23). These investigators obtained a precision of 0.1 mV in the potential differences between a mercury jet and Pt H2 and AgCl Ag electrodes in aqueous solutions of HCl. 

Fig. 8.6 The linear dependence of /ijjn on for the reduction of BQ in acetonitrile at a mercury working electrode in a wall-jet cell. Reproduced from R.G. Compton et a/., /. Electroanal. Chem. Ill (1990) 83, with permission from Elsevier.

One can imagine that to go from the VDME to a streaming mercury electrode would be another obvious step many experiments in this connection have been carried out, e.g., the use of a jet-type Hg electrode as depicted in Fig. 3.70. However, the results obtained so far are not sufficiently reliable, so that the streaming Hg electrode has not found general acceptance. 

A natural extension of the VDME is the streaming mercury electrode [74] where a fine jet of mercury issues from the capillary and is limited by a glass plate. Although some theoretical treatments are available, the poor definition of the length, radius and surface velocity of the mercury... 

The portable instrumentation and low power demands of stripping analysis satisfy many of the requirements for on-site and in situ measurements of trace metals. Stripping-based automated flow analyzers were developed for continuous on-line monitoring of trace metals since the mid-1970s [16,17]. These flow systems involve an electrochemical flow detector based on a wall-jet or thin-layer configuration along with a mercury-coated working electrode, and downstream reference and counter electrodes. 

Convection terms commonly crop up with the dropping mercury electrode, rotating disk electrodes and in what has become known as hydrodynamic voltammetry, where the electrolyte is made to flow past an electrode in some reproducible way (e.g. the impinging jet, channel and tubular flows, vibrating electrodes, etc). This is discussed in Chap. 13. 

It is evident that the solution of equations such as eqn. (1) requires a knowledge of the terms vx,vy, and vz. It transpires (vide infra) that theoretical treatments of channel electrode problems are generally mathematically simpler than the corresponding analyses for dropping mercury, rotating disc, wall-jet, or microelectrodes. This arises since the solution flowing over the electrode may, to a good approximation, be considered to have a velocity which, close to the electrode surface, increases linearly with distance away from the electrode. Thus, for channel electrodes, vx,vy, and vz are described by the equations... 

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