Monitoring the TiO₂-Photocatalyzed Destruction of Aqueous Environmental Contaminants at Parts-per-trillion Levels Using Membrane Introduction Mass Spectrometry (MIMS)

Abstract

Membrane introduction mass spectrometry (MIMS) was used to directly monitor the TiO₂/UV-photocatalyzed destruction of acetophenone, toluene, and chloroform in H₂O at ppm to pptr concentrations. The instrument response time was sufficiently rapid for these environmental contaminants (1–6 min) that “real-time” monitoring of their degradation was possible. This method was used to follow the loss of toluene at pptr levels and the concomitant formation of one of its primary photo-oxidation intermediates, methylphenol. These results illustrate the potential use of MIMS as a sensitive on-line measurement technique for monitoring photocatalytic destruction of trace organic contaminants in water at environmentally relevant levels.

Keywords:

• Membrane introduction mass spectrometry
• Membrane inlet mass spectrometry
• Photocatalysis
• Titanium dioxide
• Toluene
• Chloroform
• Acetophenone
• Advanced oxidation

Acknowledgments

The authors wish to thank the Canada Foundation for Innovation (CFI), the British Columbia Knowledge Development Fund (BCKDF), and the Science Council of British Columbia for infrastructure funding (MIMS instrumentation), Malaspina University-College for support of the Applied Environmental Research Laboratories (AERL), and the Malaspina Research Fund (MRF) for partially funding this work.