Characterization and design of porphyrins-based broad selectivity chemical sensors for electronic nose applications

The absolute selectivity of chemical sensors ceased in the last years to be a fundamental feature due to the uprising of many applications, such as electronic noses, which require the presence of broad selectivity sensors. On the other hand for these applications the attention is paid to the development of sensors whose broad selectivity can be oriented towards different classes of molecules representing a given environment in order to optimize the interface between the sensitive layers deposited on transducers and the chemical complexity of the environment itself. In this paper the main problems in the design and characterization of such sensors are presented and discussed in the case of a class of molecules, such as metallo-porphyrins, which have been recently exploited as sensitive layers in electronic nose applications.