Highly Selective Ethanol MEMS Sensor and U-Disk Detector Based on Solid Phase Extraction for Breath Alcohol Detection

Drunk driving is a major threat to global traffic safety, accounting for 50% to 60% of traffic accidents. To address the bottleneck problem of insufficient selectivity of metal oxide gas sensors in drunk driving detection, this paper proposes an optimization strategy based on the principle of selective extraction and programmed temperature desorption technology. This strategy uses temperature modulation to control the adsorption processes of target gases, solving the cross-interference problem between ethanol and other volatile organic compounds in exhaled breath. A temperature-modulated on-chip programmed temperature desorption ethanol sensor was developed using ZSM-5 and Pt@SnO₂ as the adsorption and desorption material and gas-sensitive material for ethanol, respectively. By optimizing the temperature modulation parameters (heating and cooling rates, adsorption time), the height of the ethanol desorption peak was precisely quantified. The maximum deviation of the desorption peak height of interfering gases and their mixtures with ethanol (40 ppm) in human exhaled breath from the detection instrument was only equivalent to 5.20 ppm ethanol. The highly selective ethanol sensor was integrated into the USB detection terminal to form a portable U-disk drunk driving detector, which has significantly better sensitivity and anti-interference ability than senior commercial products. The high selectivity is essentially due to the rapid extraction of ethanol from the environment by ZSM-5 in a short time.