Publications by authors named "Stefan Mitschke"

An in-house-built ion trap mass spectrometer combined with a soft ionization source has been set up and tested. As ionization source, an electron beam pumped vacuum UV (VUV) excimer lamp (EBEL) was used for single-photon ionization. It was shown that soft ionization allows the reduction of fragmentation of the target analytes and the suppression of most matrix components.

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In tobacco research, the comparison of different tobacco blends as well as the puff-dependent behaviour of cigarettes is a matter of particular interest. For the investigation of smoke characteristics, GC x GC offers different ways for data analysis, namely, compound target analysis, automated peak-based compound classification and comprehensive pixel-based data analysis. This study will show the application as well as the pros and cons of these types of data analysis for very complex matrices like cigarette particulate matter.

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Soft single photon ionisation (SPI)-time-of-flight mass spectrometry (TOFMS) is applied for the characterisation and comparison of puff-by-puff resolved and total yields of cigarette mainstream smoke from single tobacco type cigarettes (Virginia, Oriental, Burley, and Maryland) and the 2R4F University of Kentucky research cigarette. Puff-by-puff characteristics of various smoke components within one cigarette type as well as between different cigarette types can differ tremendously. This is demonstrated by means of a few selected compounds.

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The hyphenation of gas chromatography and mass spectrometry (GC/MS) revolutionized organic analysis. In GC/MS coupling, usually electron impact ionization is applied, and molecules are identified by their fragment pattern. Although mass spectrometry in principle is a separation method, it is used predominantly as a spectrometric technique.

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Atmospheric aerosols are subject to be responsible for human health effects. In this context, besides mass and number concentration of particles, their chemical composition has gained interest recently. However, knowledge about the organic content of particulate matter is still relatively scarce; i.

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Soft single photon ionization (SPI)-time-of-flight mass spectrometry (TOFMS) has been applied for the quantitative puff-by-puff-resolved characterization of selected toxic species in cigarette mainstream smoke, namely, nitric oxide (NO), acetaldehyde, butadiene, acetone, isoprene, benzene, toluene, ethyl benzene, and xylene. The 2R4F research cigarette was investigated for whole smoke (unfiltered) and gas phase (filtered). It has been demonstrated that the existing smoking regime for total smoke analysis (smoke from a complete cigarette) features deficiencies when applied to puff-resolved measurements.

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The application of soft photoionization mass spectrometry methods (PIMS) for cigarette mainstream smoke analysis is demonstrated. Resonance-enhanced multiphoton ionization (REMPI) at 260 nm and vacuum ultraviolet light single-photon ionization (SPI) at 118 nm were used in combination with time-of-flight mass spectrometry (TOFMS). An optimized smoking machine with reduced memory effects of smoke components was constructed, which in combination with the REMPI/SPI-TOFMS instrument allows PIMS smoke analysis with a time resolution of up to 10 Hz.

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