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. The complementary character of both PIMS methods is demonstrated. SPI allows the detection of various aliphatic and aromatic compounds in smoke up to approximately 120 m/z while REMPI is well suited for aromatic compounds. The capability of the instrument coupled to the novel sampling system for puff-by-puff resolved measurements is demonstrated. The feasibility of using the experimental system for intrapuff smoke measurements is also shown. Two main patterns of puff-by-puff behaviors are observed for different smoke constituents. The first group exhibits a constant increase in smoke constituent yield from the first to the last puff. The second group shows a high yield of the constituent in the first puff, with lower and constant or slowly increasing yields in the following puffs. A third group cannot be clearly classified and is a combination of both observed profiles.

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. This is especially the case for analysis in which a glass fiber filter is used to separate the smoke particulate and gas phases because material is desorbed from the filter and influences succeeding puffs. Regarding whole smoke measurements, succeeding puffs are affected by contamination and memory effects of the smoking machine itself, but to a lower extent. Quantitative puff-resolved smoke profiles show that the puff yields of the various constituents can differ tremendously. Most species' concentrations increase gradually with puff number, which is mainly due to the reduction in length of the cigarette. However, high yields in the first puff are observed for butadiene and isoprene, suggesting different formation mechanisms for these compounds. First results are presented in which these high yields in the first puff are mainly associated with the gaseous fraction of the smoke.

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. However, if soft (i.e., fragmentation-free) ionization techniques are applied, the inherent separation character of MS is emphasized, which has similarities to a GC boiling point separation. By combining polar column GC separation and fast soft ionization time-of-flight mass spectrometry technology, a comprehensive separation of complex petrochemical samples can be obtained (GC x MS approach). Compounds of comparable physical-chemical properties are characteristically grouped together in a two-dimensional retention time-m/z representation. This resembles the separation characteristics of comprehensive two-dimensional gas chromatography (GC x GC) and, thus, represents a novel multidimensional separation approach. In this work, a gas chromatograph equipped with a polar separation column was coupled to a home-built laser ionization time-of-flight mass spectrometer. Laser-based, single-photon ionization was used for universal soft ionization and resonance-enhanced multiphoton ionization for selective ionization of aromatic compounds. A novel capillary-jet inlet system was used for the coupling. Multidimensional comprehensive analysis of complex petrochemical hydrocarbon samples using gas chromatography coupled to mass spectrometry with soft and selective photo ionization sources is first demonstrated.

Application of comprehensive two-dimensional gas chromatography mass spectrometry and different types of data analysis for the investigation of cigarette particulate matterIn tobacco research, the comparison of different tobacco blends as well as the puffdependent behaviour of cigarettes is a matter of particular interest. For the investigation of smoke characteristics, GC6GC 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. In addition, new aspects about the recently discovered puff-dependent behaviour of compounds in cigarette smoke will be presented. Automated peak-based compound classification including mass spectrometric pattern recognition is used for the classification of tobacco particulate matter samples and the puff-dependent investigation of different compound classes. This compound group specific analysis is further reinforced by applying an even more comprehensive pixel-based analysis. This kind of analysis is used to generate fingerprints of different types of cigarettes. The combination of fast feature reduction methods like analysis of variance (ANOVA) and t-test with multivariate feature transformation methods like partial least squares discriminate analysis (PLSDA) for feature selection provides a powerful tool for a detailed inspection of different types of cigarettes.

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Several ionization potentials (IPs) of security relevant substances were determined with single photon ionization time of flight mass spectrometry (SPI-TOFMS) using monochromatized synchrotron radiation from the "Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung" (BESSY). In detail, the IPs of nine explosives and related compounds, seven narcotics and narcotics precursors, and one chemical warfare agent (CWA) precursor were determined, whereas six IPs already known from the literature were verified correctly. From seven other substances, including one CWA precursor, the IP could not be determined as the molecule ion peak could not be detected. For these substances the appearance energy (AE) of a main fragment was determined. The analyzed security-relevant substances showed IPs significantly below the IPs of common matrix compounds such as nitrogen and oxygen. Therefore, it is possible to find photon energies in between, whereby the molecules of interest can be detected with SPI in very low concentrations due to the shielding of the matrix. All determined IPs except the one of the explosive EGDN were below 10.5 eV. Hence, laser-generated 118 nm photons can be applied for detecting almost all security-relevant substances by, e.g., SPI-TOFMS.

Pyrolysis single-photon ionisation (SPI)-time-of-flight mass spectrometry (TOFMS) and statistical analysis techniques have been applied to differentiate three major tobacco types, Burley, Virginia and Oriental, by means of the gas phase. SPI is known as a soft ionisation technique that allows fast and comprehensive on-line monitoring of a large variety of aliphatic and aromatic substances without fragmentation of the molecule ions. The tobacco samples were pyrolysed at 800 degrees C in a nitrogen atmosphere. The resulting pyrolysis gas contained signals from more than 70 masses between m/z 5 and 170. Mass spectra obtained were analysed by principal component analysis (PCA) and linear discriminant analysis (LDA) to distinguish between different tobacco types. Prior variable reduction of the data set was carried out by calculation of the Fisher ratios. Results achieved give information about chemical composition and characteristics of the smoke derived from each tobacco type and enable conclusions on plant cultivation to be drawn. Based on LDA, a model for tobacco type recognition of unknown samples was established, which was cross-checked by additional measurements of each tobacco type. Furthermore, first results on the recognition of tobacco mixtures based on principal component regression (PCR) are presented.