Hydrogen cyanide sensor

Other usefiil gas sensors include the potentiometric ammonia (64) or hydrogen cyanide probes (65), and amperometric carbon monoxide (66) and nitrogen dioxide (67) devices. The hydrogen cyanide probe is an example of a modem device that relies on changes in the conductivity of electropolymerized film (polyanihne) in the presence of a given gas. 

An alternative approach, adopted by Albery et al. [59-61], is to determine the mechanism giving rise to the sensor response and to use this information together with the measured data at short times to calculate the final response. This was used for an electrochemical sensor system incorporating cytochrome oxidase where the steady-state responses of the measurement system were insufficiently fast for useful measurement of respiratory inhibitors such as cyanide, hydrogen sulphide, etc. By using mechanistic information, it was possible to successfully calculate the concentration in a test sample by real-time analysis of the sensor signals at short times after exposure to the test sample. The analysis could cope with the gradual loss of enzyme activity commonly found in these biosensor devices. 

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