Polypyrrole based aroma sensor

The change in conductivity of conducting polymers when exposed to volatile gases can be exploited for the construction of aroma sensors. In this communication we report the preliminary tests of two versions of an aroma sensor based on arrays of doped polypyrrole films. We have used these prototypes for the identification of simple organic vapors and complex aromas. The input signal was the fractional change in the resistance of the films and the data acquisition was performed automatically. The pattern recognition process was implemented by a multivariate analysis and by neural network processing. The discriminating power among different odorants was better than 90%.