Electronic Nose Based on Conducting Polymers for the Discrimination of Medicinal Plants

Abstract

An electronic nose based on chemiresistors employing conducting polymers as the sensing material was developed for the discrimination of medicinal plants. The conducting polymers were synthesized through potentiostatic electropolymerization and deposited between two gold wires set 200 μm apart on a Teflon substrate. The polymers were doped with several counter ions. The resistance of the doped polymers changed upon exposure to the headspace of of finely-chopped leaves of the following medicinal plants: Vitex negundo (Lagundi), Mentha arvensis (Yerba Buena), Mentha piperita (Peppermint), Artemisia dracunculus (Taraggon), Blumea balsafimera (Sambong), and Plectranthus amboinicus (Cuban Oregano). The different plant samples yielded distinct responses from the sensor array. The results were subjected to pattern recognition techniques, such as radar plots, principal component analysis (PCA) and dendrogram analysis (DA). PCA showed good discrimination among plant samples. DA confirmed the observed clustering in PCA.