Laser-induced molecular ion formation and gas-phase ion formation from polycyclic aromatic hydrocarbons,coals and coal products detected by Fourier transform mass spectrometry |
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Authors: | Paul F Greenwood Michael G Strachan Gary D Willett Michael A Wilson |
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Abstract: | The results from the laser-ablation Fourier transform mass spectrometric examination of a variety of polyaromatic hydrocarbons (PAHs), coals and other geochemically related materials are presented. Both molecular and quasi-molecular ions have been detected from different ring-sized PAHs. A relationship between the ease of sodium-adduct ion formation and the size of the aromatic array is observed. Nevertheless, suppression of M + Na]+ ion formation in PAHs can be achieved by the addition of coal. In addition, distributions of low-mass positive- and negative-ion carbon clusters (Cn +, 14 ? n ? 27 and Cn, ?, 4 ? n ? 30), high-mass positive-ion carbon clusters (Cn+, 60 ? n ? 260) and low relative molecular mass organic compounds (< 600 daltons) have been observed from the coals. It appears that the ease of C formation may be used as an indicator of coal rank. Irradiance conditions also influence the observed distribution of high-mass positive-ion carbon clusters. Furthermore, distributions of the high-mass positive-ion carbon clusters at different irradiances supports an earlier proposal that their formation is kinetically controlled. |
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