Cyclic voltammetry sensors, amperometric

If one wishes to verify whether the prewave can form the basis for an amperometric sensor, one would preferably dispose of as much information as possible concerning the nature and the properties of this wave. An obvious technique for diagnosis is cyclic voltammetry. Hydrogen peroxide can be oxidised as well as reduced at glassy-carbon electrodes however, the potential ranges within which the reactions occur are situated relatively distant from each other, as can be seen in Fig. 4.3 and Fig. 4.5. 

Figure 2. Cyclic voltammetry showing oxygen interference on chlorine detection. Bare amperometric sensor in a 0.1 M KC1 solution, 1) N2, 2) N2 +...

Oxygen ion conductors are used in amperometric sensors for a variety of gas species. The selectivity is controlled by selecting electrode materials that catalyze particular reactions hence, multiple electrodes are required for some multicomponent gas mixtures. In such cases, the system is designed so that each electrode removes a particular gas from the gas stream. The particular gas removed by a particular electrode can also be controlled by the voltage at the electrode, just as in cyclic voltammetry, which has also been used in solid-electrolyte based sensors [34]. In addition to providing selectivity, control of the applied voltage can be used to improve the magnitude of the response [35]. 

Preliminary results are presented for the use of cyclic voltammetiy as a method for pattern recognition. The current at eight potentials of a cyclic voltammgramm was analyzed and these values served as a simulation of eight amperometric sensors. It is shown that on the basis of this procedure, different explosives and apple juices are easily distinguished by the use of one electrode alone These results clearly show that cyclic voltammetry could easily be used for a so called electronic tongue. In the future it is planned to use cyclic voltammetry as a method in combination with different sensor methods and also for the vapour detection. 

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