Thermoelectric Array Sensors with Selective Combustion Catalysts for Breath Gas Monitoring.

ABSTRACT: Inflammable breath gases such as H? and CH? are used as bio markers for monitoring the condition of the colon. However, their typical concentrations of below 100 ppm pose sensitivity and selectivity challenges to current gas sensing systems without the use of chromatography. We fabricated a compact, gas-selective thermoelectric array sensor (TAS) that uses micro-machined sensor devices with three different combustion catalysts to detect gases such as H?, CO, and CH? in breath. Using Pt/Pt-W thin-film micro-heater meanders, Pd/Al?O?, Pt,Pd,Au/Co?O?, and Pt/Al?O? catalysts were heated to 320, 200, and 125 °C, respectively, and the gas sensing performances of the TAS for each gas and for a model breath gas mixture of 100 ppm H?, 25 ppm CO, 50 ppm CH?, and 199 ppm CO? in air were investigated. Owing to its high catalyst temperature, the Pd/Al?O? catalyst burned all three gases, while the Pt,Pd,Au/Co?O? burned CO and H? and the Pt/Al?O? burned H? selectively. To calibrate the gas concentration of the mixture gas without the use of a gas separation tool, linear discriminant analysis was applied to measure the sensing performance of TAS. To enhance the gas selectivity against H?, a double catalyst structure was integrated into the TAS sensor.

SUBMITTER: Shin W 

PROVIDER: S-EPMC5982651 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature