Abstract
Non-equilibrium plasma based technologies are currently being developed for the abatement of volatile organic compounds (VOCs). The promising results obtained so far encourage efforts in fundamental research to improve our knowledge of the processes involved. To gain insight into the role played by analyte-derived ionic species we have investigated the ion chemistry of trichlorethylene (TCE), a representative VOC, in air at ambient pressure by means of an atmospheric pressure chemical ionization commercial mass spectrometer. Different experimental conditions were examined with regard to the following parameters: ion source temperature, water and TCE concentrations, and extraction potential. Notably, modulation of the variable extraction potential provided a means to probe structure and reactivity of the ionic species of interest. Products resulting from TCE oxidation were observed in the analysis of both positive and negative ions. Particularly prominent is a C2H2Cl2O+. species, likely of enol structure, due to reaction with water. A reaction scheme is proposed based on nucleophilic addition of water to ionized TCE followed by elimination of HCl. The negative ion chemistry of TCE is dominated by Cl− and its clusters with water and TCE. At low temperature and with water in high concentration very large positive and negative ion hydrate clusters (with up to 50 water molecules) could be observed. © 1997 John Wiley & Sons, Ltd.
Published Version
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