A Pre-Concentration System Design for Electronic Nose via Finite Element Method

Volatile organic compounds (VOCs), which is measured by electronic nose (e-nose), have utilities as biomarkers for classification and detection. However, the concentration of biomarker in VOCs is usually lower than the detection limit of gas sensors of e-nose, which results in systematic failure. The VOCs enrichment technology can be used to break through the limitations via enriching the low concentration of VOCs with adsorption tubes. In this paper, a pre-concentration system is designed based on the finite element method. Through the finite element analysis, the pre-concentration system can efficiently determine parameters to control the temperature field. In addition, with the expanded adsorption range of VOCs C3-C30, the lower bound of adsorption is analytically proved by C3H8O (including n-propanol and isopropanol). Moreover, the conformal technique is exploited to improve the enrichment efficiency. Also, the upper bound of adsorbable VOCs can be further improved via the double adsorption tubes structure design. Finally, gas chromatography-mass spectrometry (GC-MS) and e-nose are used to detect the concentration of the different sample gas before and after the pre-concentration device, and the results show the effectiveness of the design.