MASS-SPECTROMETRY ONLINE MONITORING AND MS2 PRODUCT CHARACTERIZATION OF TIO2 UV PHOTOCATALYTIC DEGRADATION OF CHLORINATED VOLATILE ORGANIC-COMPOUNDS/

On-line Mass Spectrometry and MS2 are applied to monitor and identify the by-products and total mineralization products of TiO2/UV photocata lytic degradation of four chlorinated volatile organic compounds (VOCs ): trichloroethylene (TCE), tetrachloroethylene (TeCE), chloroform, an d dichloromethane. Selected multiple ion mass spectrometry monitoring using characteristic 70 eV electron ionization ionic fragments monitor s in real time the destruction of the starting VOC and the formation o f by-products, i.e., the degrees of VOC mineralization, as a function of the flow and relative humidity of the carrier gas (synthetic air). Several by-products were detected: phosgene for TCE, TeCE, and chlorof orm dichloroacetyl chloride for TCE; and trichloroacetyl chloride for TeCE. Cl-2 and CO2 were also detected as final mineralization products of the four chlorinated VOCs. Structural characterization of byproduc ts was accomplished via MS2 collision-induced dissociation of molecula r ions or characteristic ionic fragments. (C) 1998 American Society fo r Mass Spectrometry.