Nanocomposite-Based Chemiresistive Electronic Nose and Application in Coffee Analysis

The demand for accurate and rapid quality inspection of agricultural and food products has progressively increased since it is one of the important key attributes in determining consumer preference. In this sense, electronic nose (e-nose) devices capable of capturing a "smellprint" of food products, combined to pattern recognition tools are advantageous for the discrimination of similar complex mixtures. The design of the sensing units composing the e-nose requires a judicious choice of materials with distinct selectivity and specificity for achieving outstanding performance. The present work reports on the development of an e-nose based on nanocomposites obtained by the combination of ZnO, In2O3, and ZnO/In2O3 nanoparticles with polypyrrole and poly(styrenesulfonate). The sensor array was composed by six sensing units, which were exposed to 17 coffee samples. The coffee samples were successfully discriminated by quality level with the aid of principal components analysis and Euclidian distances by dendrograms. Therefore, the sensor array made with nanocomposites is promising as an alternative tool for monitoring the quality and classification of coffee samples.