Physisorption based sensors

All chemical sensors presently in use or in development are based on a two-step detection mechanism [1]. In the first step, chemical selectivity is achieved by a chemical reaction or chemi- or physisorption on a chemically selective surface as listed in table 1. In the second step, a physical change, which is the result of the first selective chemical step, is transformed by a suitable transducer into an electrical signal. This physical change can be a variation of the chemical potential, caused by the reaction or sorption process, a change in optical properties, a change in mass, conductivity, surface resistance or conductance. The physical effects listed in table 2 in column 1 can now be combined with the various transducers listed in column 2 in a suitable way. They will yield the total spectrum of chemical sensor types presently under investigation. 

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