Authors: M. Righettoni, A. Tricoli, S. Gass, S.E. Pratsinis
Affilation: ETH Zürich, Switzerland
Pages: 9 - 11
Keywords: gas sensor, WO3, breath analysis, diabetes
The detection of acetone in the human breath is a promising method for the noninvasive diagnosis and monitoring of diabetes. Here, a portable and highly selective acetone-sensor was developed by direct flame synthesis and deposition of a chemo-resistive nanostructured SiO2-doped WO3 film on back-heated interdigitated Pt electrodes on an alumina substrate inside a T-shape chamber of similar size to a mobile telephone. This device enables real-time measurements of ultra low (≤ 20 ppb) acetone concentrations at realistic breath conditions (90% relative humidity). The sensing properties (selectivity, detection limit, sensor response and recovery times) were investigated as a function of operating temperature, relative humidity, interfering analyte concentration (ethanol) and inlet flow-rate. The optimized device resulted in short (10 - 20 s) total response and recovery times. Furthermore, the sensor response was robust against changes in the inlet volumetric flow-rate.