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  • Photosensitized degradation kinetics of trace halogenated contaminants in natural waters using membrane introduction mass spectrometry as an in situ reaction monitor.

Photosensitized degradation kinetics of trace halogenated contaminants in natural waters using membrane introduction mass spectrometry as an in situ reaction monitor.

Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology (2015-10-07)
Dane R Letourneau, Chris G Gill, Erik T Krogh
RESUMEN

The photochemically mediated dechlorination of polyhalogenated compounds represents a potential decontamination strategy and a relevant environmental process in chemically reducing media. We report the UV irradiation of natural and artificial waters containing natural dissolved organic matter to effect the photo-sensitized degradation of chlorinated organic compounds, including tetrachloromethane, 1,1,1-tricloroethane, perchloroethene, 1,2-dibromo-3-chloropropane and chlorobenzene at trace (ppb) levels in aqueous solution. The degradation kinetics are followed in situ using membrane introduction mass spectrometry. By re-circulating the reaction mixture in a closed loop configuration over a semi-permeable hollow fiber polydimethylsiloxane membrane in a flow cell interface, volatile and semi-volatile compounds are continuously monitored using a quadrupole ion trap mass spectrometer. The time resolved quantitative information provides useful mechanistic insights, including kinetic data. Pseudo first-order rate constants for the degradation of contaminant mixtures in natural waters are reported.

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