Preparation and characterization of nanostructured materials for an artificial olfactory sensing system

Pure and Ni-, Pt-, Pd-, Os-doped tin oxide and pure and Fe-doped indium oxide thin films have been prepared by the sol–gel process. The microstructural properties of the as-prepared films have been investigated by means of X-ray diffraction (XRD). All the samples showed a polycrystalline structure that resulted to be dependent on the presence of the particular doping element. Integrated gas microsensor devices based on both pure and doped sol–gel thin films of these two different metal oxides (SnO2 and In2O3) were realized. They were linked in an array configuration and exposed to the volatile compounds of different commercial olive oils samples in order to test the application of the array in an electronic nose for the discrimination among different commercial olive oils. The differently modified sensitive materials showed different sensing characteristics to the headspace of the olive oil, hence modulating the selectivity of the array. PCA analysis was performed on the array responses and the results showed the capability to discriminate olive oils of different quality.