Analysis of vapours and foods by means of an electronic nose based on a sol–gel metal oxide sensors array

In this paper, a novel electronic nose based on a metal oxide gas sensors array, prepared by means of the sol–gel method in the form of thin films, is described, including the fabrication process. Two different configurations of the array were developed: one consisting of sensors with the same sensing layer (SnO2) but different geometry and material for the electrical electrodes, and another consisting of chemically modified SnO2 thin films. Examples of application to the analysis of air pollutants (CO, NO2, CH4, C2H5OH and CH3OH) and different foods (oil, milk, tomato, wine, ground coffee). Recognition of different air contaminants and of the aroma of foods is achieved by using the principal component analysis (PCA). Good discrimination among the clusters has been obtained indicating promising results for the application of our sensor array as electronic nose, in particular in the food industry for the classification of different olive oils.