Aroma detection using a gas sensor array with different polyaniline films

This paper presents a gas sensor array designed to be an electronic nose system characterized for the detection of different aromas (grape, apple, and strawberry). The gas sensors were prepared on printed graphite interdigitated electrodes (PGIEs with a tracing paper substrate) or gold interdigitated electrodes (IDEs with a glass substrate). The polyaniline (Pani) sensitive layers, obtained by interfacial and in situ synthesis, were deposited using layer-by-layer (LbL) and direct in situ adsorption polymerization. Experimental results showed that the substrate significantly affected the sensor responses, where sensors fabricated on PGIEs presented the highest sensitivity. On the other hand, the IDE sensors showed the best limit of detection (LOD), and short response times and recovery times for different aromas. The atomic force microscopy technique showed a typical morphology for all Pani films, where films deposited using the LbL technique presented the highest roughness. The sensor array was efficient in aroma discrimination, so it demonstrates excellent potential for food analysis in industrial applications.