SAW mono sensor for identification of harmful vapors using PCA and ANN

A functionalized polymer (SXFA: fluoroalcoholpolysiloxane) coated single surface acoustic wave (SAW) sensor E-Nose is proposed for the detection of harmful vapors by operating at different temperature. The polymer coated SAW sensor is used along with a reference SAW device in dual Colpitt's oscillator configuration. The sensor is tested with four different classes of vapors at different concentrations in an environmental chamber whose temperature can be varied in the range −20 to +70 °C. The sensor showed variation in response with exposure to benzene, methanol, diesel and DMMP vapors at different temperatures. The polymer coated SAW sensor was giving frequency shifts of 0.21–1.12 kHz for methanol (1000–4000 ppm), 0.3–2.69 kHz for benzene (400–1600 ppm), 0.81–7.39 kHz for diesel (12–48 ppm) and 4.27–8.07 kHz for DMMP (1–10 ppm) vapors at 30 °C operating temperature. Principal component analysis and artificial neural network algorithms are successfully implemented to classify and detect the target vapors.