Hot-wire electrochemistry

Gaines Jr GL (1966) Insoluble monolayers at liquid-gas interfaces. Wiley, New York Grundler P, Kirbs A (1999) The technology of hot-wire electrochemistry. Electroanalysis 11 223-228... 

Direct Electric Heating Hot-Wire Electrochemistry and Hot-Layer Electrochemistry ... 

Direct electric heating has been applied with a large variety of electrode designs including flat structures, heated paste reservoirs, etc. Some of them are /Macroelectrodes which normally are restricted to permanent heating experiments. The familiar term hot-wire electrochemistry traditionally is used preferentially for experiments with pulsed heating where microelectrodes are in use. 

This chapter is dedicated explicitly to the hot-wire electrochemistry , since, at present, it represents the only fully developed technique in the inventory of modem thermoelectrochemistry. It has found its way into the analytical laboratory. Also,... 

Some of the technical characteristics of hot-wire electrochemistry have been summarised in several papers with experimental orientation [1-6]. The term Hot-Wire Electrochemistry became familiar after it had been mentioned first in a scientific discussion. 

Including item (c), the stagnant solution layer in contact with the heated electrode surface, we can state that cylindric microelectrode properties in combination with heat distribution and streaming processes reveal some surprising characteristics which have been utilised in hot-wire electrochemistry much more than this has been done in common applications before. 

The basic configuration of hot-wire electrochemistry is simple. Every commercial potentiostat can be combined with a high frequency heating unit to form the actual bridge circuit which had been outlined schematically in Fig. 4.12c. 

The thermoelectric spectra mentioned above have been recorded in a more extended way for different species. They played an important role in the early time when hot-wire electrochemistry has been established. Extended pictures like that in Fig. 6.11 allow to understand that TPV curves may assume different shapes dependent on the length of heating-up and cooling-down periods. For heat pulses of very long duration, when actual current rise has ceased, the resulting TPV... 

Thin pencil leads 0.3 mm in diameter have been proposed as heated carbonaceous electrodes. Successful determination of riboflavin [41], rutin [42], flavin adenine dinucleotide [43], silybin [44] and luteolin [45] has been reported. Mostly, direct heating was applied following the principles of hot-wire electrochemistry, but a sensor with indirect heating was proposed also [45]. 

Hot-wire electrochemistry with directly pulse-heated microwire electrodes can be considered to be a special branch of high-temperature electrochemistry. It is characterised by two attributes (1) it can be done with common, generally available instruments and (2) in contrast to classical high-T-electrochemistry, the increased temperature is applied only where it is required, but all other regions of the cell content remain unaffected. These characteristics are of practical, not of fundamental, nature. It means that the results of this technology would be available in most cases also with classical high pressure electrochemical cells. 

Commercial instruments are the easiest and the most reliable way but not the cheapest one to get experience in hot-wire electrochemistry. For home constructors among interested scientists who prefer to find a cheaper solution, in the following paragraphs a home-built apparatus will be presented. Capability of this device is on a par with commercial instruments. The inner stmcture of the arrangement is depicted schematically in Fig. Bl. In Fig. B2, the apparatus is shown as it was used in the author s laboratory, i.e. in an experimental state. 

His research interests were mostly coimected with analytical application of electrochemistry, in the past mainly for precision analysis and later for electrochemical sensors of different kinds. In the years after 1990, he picked up an idea which he had since long and started working with heated microelectrodes. The resulting package of methods, named later hot-wire electrochemistry , finally became the origin of a critical reconsideration of the scientific subject thermoelectrochemistry as a whole. 

After being used in many different regions of the world and discussed at many conferences, hot wire electrochemistry has become part of a larger field. It has therefore been decided to summarize all the effort made to apply temperature changes to the surface of an electrode as an intentionally varied external parameter. The history of all that is known as thermoelectrochemistry is also related, and these areas represent the main subjects covered in this book. Experimental experiences are also related, together with many useful tricks . 

I thank all my young friends who worked together with me during one of the most fruitful and happy periods of my life, when we worked out together the hot-wire electrochemistry. Thank you, Tadesse, Andreas, Torsten, Andre, Markus and Bello ... 

I am very grateful to my late friend Lothar Dunsch who offered me the chance to continue to work with hot-wire electrochemistry after my retirement from the university, in the wonderful atmosphere of his group. 

Grundler, P, Degenring, D. The limits of aqueous hot-wire electrochemistry Near-critical and supercritical fluids in electrochemical sensors Electroanalysis 2001,13,755-759. 

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