Electrochemical Sensor for Integral Determination of Toxic Substances in "Electronic Nose" Format at Monitoring Mode

The paper presents the results of research aimed at developing an electrochemical sensor for determination of integral toxicity level in the air. The sensor embodies the electrochemical method of multisensory stripping voltammetry with the accumulation of cathodic reaction products. This method allows analysis of toxic substances of different chemical classes, which are present in low concentrations in the medium under study. A specific feature of the sensor is that its electrochemical test-system is a solution containing a set of metal cations capable of forming complex compounds with toxic substances. In this case, it is not necessary to employ several electrodes with specific selectivity towards toxic substances of different chemical classes. We carried out the analysis using a single electrode, and the role of each sensor was performed by metal cations that made up the test-system. The experimental findings show that the testsystem is able to determine a quite wide range of toxic substances. This means that it can be used to determine the integral level of toxicity of the environmental air since the combined effect of toxic substances on the test-system (due to the formation of complex compounds as a result of reactions between toxic substances and metals of the test-system) produces changes in the resulting voltammograms as compared to the reference one. The time taken to record a voltammogram is small, therefore measurement cycles can be carried out with 20-second intervals. Hence, it is possible to monitor the environmental air for toxic substances in real time. The article provides a schematic diagram of the sensor. The sensor operates as an electronic nose device in a realtime air monitoring mode. The developed software allows air monitoring to be carried out without the direct involvement of the operator. The final results of the evaluation of the integral toxicity of air are produced automatically.

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