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Five gas-phase compounds in fresh sidestream cigarette smoke were determined using Fourier transform infrared (FTIR) spectrometry. Ammonia, carbon dioxide, carbon monoxide, hydrogen cyanide and nitric oxide yields for five different cigarette brands were measured. Gas concentrations in the sidestream smoke were calculated from absorbance measurements made approximately every 30 s. Component yields were calculated by integrating the concentration versus time curves over the cigarette smoking period with incorporation of sample flow and gas cell pressure data. Results of these measurements were compared with measurements made using standard analytical techniques: infrared absorption using non-dispersive infrared (NDIR) analysers for the determination of carbon dioxide and carbon monoxide, chemiluminescence for nitric oxide and spectrophotometric-based methods for ammonia and hydrogen cyanide. Statistical analysis of the results indicates that the FTIR-based method and the standard methods are equivalent for two analytes, ammonia and carbon dioxide, but are significantly different for carbon monoxide, hydrogen cyanide and nitric oxide. The mean yields per cigarette for carbon monoxide, hydrogen cyanide, and nitric oxide using the FTIR-based method are approximately 45% higher than those for the NDIR-, spectrophotometric-and chemiluminescence-based methods used for these compounds.

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The Rydberg states of H2S have been investigated by multiphoton ionization, resonant enhanced at the two-photon and three-photon level (REMPI). The REMPI spectra (ion signal vs laser wavelength) are compared to the one-photon absorption spectrum. In addition, photoelectron spectra (PES) were collected at most of the absorption peaks in both the 2+1 and 3+1 REMPI processes. The vibrational state distribution of H2S+ formed by REMPI at a number of laser wavelengths is highly peaked at a single vibrational level. These intermediate Rydberg states could therefore be assigned on the basis of the PES. The REMPI-PES at other laser wavelengths were more complex probably because of perturbed intermediate Rydberg states. A comparison of the 2+1 and 3+1 REMPI wavelength scans shows significant peak intensity differences, which we attribute to the different Δl selection rules in the two- and three-photon absorption steps. New H2S 4p Rydberg states were observed in the two-photon resonance study, and a number of previously observed peaks have been reassigned on the basis of these results.

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