Thermal desorption/pyrolysis coupled with photo ionisation time-of-flight mass spectrometry for the analysis and discrimination of pure tobacco samples
Three different tobacco samples (Burley, Virginia, and Oriental) were thermally desorbed at varying temperatures (190, 250, and 310 °C) and the evolved gas phase at every temperature step has been analyzed applying single photon ionisation (SPI)-time-of-flight mass spectrometry (TOFMS) and resonance enhanced multiphoton ionisation (REMPI)-time-of-flight mass spectrometry. These soft and selective ionisation techniques allow fast and comprehensive on-line monitoring of a large variety of aliphatic and aromatic substances with almost no fragmentation of molecular ions. Many oxygen containing compounds could be detected such as phenol, hydroquinone, and (vinyl)guiacol along with unsaturated hydrocarbons and nicotine. In addition, with REMPI a large variety of PAH are accessible. Different tobacco types yield slightly distinguished mass spectra. By utilizing statistical tools (Fisher criterion and PCA) the three tobaccos can be discerned rather rapidly from each other and possible marker compounds for a given tobacco can be identified. Extension of this newly conceived method to other biomass material and potential coupling to other methods of thermal analysis seems feasible in the future.