Real-time analysis of toluene removal in dry air by a dielectric barrier discharge using proton transfer reaction mass spectrometry

The proton transfer reaction mass spectrometry (PTR-MS) is used to follow the toluene concentration at the exit of a dielectric barrier discharge, for an inlet gas mixture of dry air with organic molecules at a concentration in the range 10–100 ppm, at atmospheric pressure and room temperature. The precursor ion is H3O+, and toluene is detected at mass 93 u, corresponding to the (C6H5CH3)–H+ ion. The PTR-MS is used together with optical absorption spectroscopies to follow ozone and carbon dioxide molecules. Two different discharge regimes are studied: without or with significant self-warming effects. The PTR-MS diagnostic appears as a very useful tool for precise monitoring of the concentration of this organic molecule, and to get real-time information about the energy efficiency for the removal of the pollutant during the discharge operation, as function of the discharge regime.