title: Resonance-enhanced multiphoton ionization for real-time monitoring of trichloroethylene formed by degradation of tetrachloroethylene using zero-valent zinc.
abstract: Resonance-enhanced multiphoton ionization (REMPI) is investigated as a potential technique for real-time monitoring of selected volatile organochloride compounds (VOCs). In a proof-of-concept experiment, the progress of the reductive-degradation of tetrachloroethylene (PCE) to trichloroethylene (TCE) by zero-valent zinc was monitored by REMPI measurements performed in the headspace above the PCE solution. Two-photon resonant REMPI spectra of TCE and PCE were recorded over the wavelength range 305-320 nm. The concentrations of PCE and TCE in the headspace were monitored by measurement of the ionization signal with 315.64- and 310.48-nm excitation for PCE and TCE, respectively. Calibration curves yielded a linear range of more than 2 orders of magnitude for both compounds. The REMPI headspace results agreed well with the solution-phase results from gas chromatography analysis, which was used for independent verification of the progress of the reaction.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
authors.forename: Kui
authors.initials: K
authors.lastname: Chen
authors.forename: Jack E
authors.initials: JE
authors.lastname: Pender
authors.forename: John L
authors.initials: JL
authors.lastname: Ferry
authors.forename: S Michael
authors.initials: SM
authors.lastname: Angel