Characterization and design of porphyrins-based broad selectivity chemicalsensors 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 el ectronic noses, which require the presence of broad selectivity sensors. On the other hand for these applications the attention is paid to the develop ment of sensors whose broad selectivity can be oriented towards different c lasses of molecules representing a given environment in order to optimize t he interface between the sensitive layers deposited on transducers and the chemical complexity of the environment itself. In this paper the main probl ems in the design and characterization of such sensors are presented and di scussed in the case of a class of molecules, such as metallo-porphyrins, wh ich have been recently exploited as sensitive layers in electronic nose app lications. (C) 1998 Elsevier Science S.A. All rights reserved.