Ozone-induction coupled with plasma assistance to enhance cataluminescence for monitoring of volatile organic compounds.

Abstract

The authors describe a strategy for ozone-induction coupling with plasma assistance (O3-I/PA) to enhance cataluminescence (CTL) based sensing of volatile organic compounds (VOCs). A homemade O3-I/PA CTL sensor system was constructed based on this strategy. O3-I/PA can significantly enhance the CTL response to many compounds that were hardly detectable previously with adequate sensitivity. Without any preconcentration, the limits of detection (for S/N = 3) are 20μg.m-3 (= 5 ppbv) for toluene and 8μg.m-3 (6.4 ppbv) for formaldehyde. VOCs including benzene, alkanes, halohydrocarbons, alkenes alcohols, aldehydes, ketones and ethers are found to produce a strong response when using this sensor system. Mechanistic studies showed that the synergistic effect of ozone-induction and plasma assistance promote the oxidation of the VOCs under formation of CO2. This strongly favors CTL emission. The sensor system can be used as a direct-reading detector for on-line and real-time monitoring of total VOCs. It also can be used as a detector in gas chromatography for the identification of individual VOCs. It is perceived that this work paves the way to both a new kind of vapor sensor and to a detection scheme in gas chromatography. Graphical abstract The synergistic effect of ozone-induction and plasma assistance promote the deep oxidation of the VOCs into CO2, which strongly favors cataluminescence emission.