Campo F., Blanco-Rodriguez A., Valiente R., Lambert B., Becherán L., De Melo Lisboa H., Durán A., 2016, Application of an Electronic Nose Coupled to a Gas Analyser for Measuring Ammonia, Chemical Engineering Transactions, 54, 127-132.
This work presents the application of an electronic nose (e-nose) based on MOS sensors, for quantitative analysis of ammonia, and its calibration regarding a commercial gas analyser. Features were extracted from the sensors responses in the time domain, the phase space and the frequency domain. Each feature was evaluated considering its repeatability discrimination capability, information content and redundancy, by using a signal to standard deviation ratio (S/s) and Principal Components Analysis (PCA). Based on this assessment, two parameters were selected from the responses of two sensors: the slope of the desorption transient and the first coefficient of a Daubechies 1 Wavelet decomposition of 11 levels. Afterwards, the four features selected were used as predictor variables in a Partial Least Square (PLS) regression, for correlating the e-nose response with the ammonia concentration measured with a gas analyser. This regression model allows the e-nose to predict the ammonia concentration values with a R2 = 0.99 and RMESCV of 1.40 ± 0.04 ppm.
