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Laser Plasma Induced Ionization of Volatile Organic Compounds - Study of the Processes and Subsequent Ion/Molecule Reactions by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Gas phase ion/molecule reactions between laser-produced positive or negative ions and organic molecules were studied by Fourier transform ion cyclotron resonance mass spectrometry. Pure metal, metal halide salt and silicon wafer targets were irradiated by laser pulse, and positive and negative ions as well as electrons were formed. Their reactivity towards volatile organic molecules was studied and reaction mechanisms established. Acetophenone was tested as a model compound for reactions with metal and silicon cations. Reactivities of different cations were correlated to their electronic configuration and promotion energy. Established experimental procedures were applied for ionization and ion-molecule reactions of polyhalogenated molecules. Perfluorotributylamine was allowed to react with 21 different elemental cations and reaction products and mechanisms were defined. Some other environmental polyhalogenated derivatives (dichlorodifluoromethane, halothane and endosulfane) were analyzed by the same method. As a complementary ionization method, negative mode ionization (reactions) were studied. Three different ionizing projectiles: laser-produced electrons and halide ions as well as fragment halide ions were used to ionize (react with) the above mentioned molecules. Electron attachment mechanisms are concurrent to negative ion/molecule reactions.

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry ; laser plasma ; ion/molecule reactions ; (negative) chemical ionization ; metal ions

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