Application of time-of-flight mass spectrometry with laser-based photoionization methods for time-resolved on-line analysis of mainstream cigarette smoke.

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.