Breath acetone monitoring by portable Si:WO3 gas sensors

Breath analysis has the potential for early stage detection and monitoring of illnesses to drastically reduce the corresponding medical costs. Here, a portable acetone sensor consisting of flame-deposited and in-situ annealed, Si-doped epsilon-WO3 nanostructured films was developed. The chamber volume was miniaturized, reaction- and diffusion-limited gas flow rates were identified and sensing temperatures were optimized resulting in low limits of detection and short responses at realistic relative humidities. The acetone content in the breath of test persons was monitored continuously (even in the presence of isoprene) and was in good agreement with state-of-the-art proton transfer reaction- mass spectrometry (PTR-MS). Such chemo-resistive sensors can accurately track acetone concentration and become an alternative to more elaborate breath analysis techniques.