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

Sensors: From biosensors to the electronic nose

“…It is easy to interpret and it is not necessary to invert the matrix when carrying out this analysis. PCA has been used (Capone et al 2000) to remove the variable redundancy, to detect the outliers (Amine et al 1999), and as pre-treatment of data previously to use neural network (Pardo et al 2000a). …”

Characterization of virgin olive oils according to its triglycerides and sterols composition by chemometric methods

“…More recently, other different techniques to the chromatographic ones have been also used. This way, classification of olive oils of different origin has been gotten using near IR spectral data in combination with an artificial neural network or with the logistic regression (Bertran et al, 2000); the high-field 1 H NMR spectroscopic data corresponding to minor constituents subjected to principal component analysis or to cluster analysis (Mannina, Patumi, Proietti, Bassi, & Segre, 2001;Sacchi et al, 1998); or the data corresponding to aroma compounds obtained by means of sensors constituting an electronic nose (Capone et al, 2000;Guadarrama, Rodr ıguez-M endez, Sanz, R ıos, & de Saja, 2001;Pardo, Sberveglieri, Gardini, & Dalcanale, 2000).…”

A new sensor for ammonia based on cyanidin-sensitized titanium dioxide film operating at room temperature

“…The response time, defined as the time taken for the sensor's resistance to reach the 90% of the steady-state resistance, is around 180-220 s. Likewise, the recovery time represents the time required by the sensitivity factor to return to 10% below its equilibrium value in air following the zeroing of the test gas ammonia and it was found to be around 240-270 s. The response and recovery times were not as high as those reported in the literature [32] and [33], indicating that NH 3 molecules are weakly attached to the sensing materials, or previously adsorbed ammonia molecules. These results indicate that cyanidin is responsible for the sensing action.…”