Determination of molecular line parameters for acrolein (C(3)H(4)O) using infrared tunable diode laser absorption spectroscopy.

Acrolein (C(3)H(4)O) molecular line parameters, including infrared (IR) absorption positions, strengths, and nitrogen broadened half-widths, must be determined since they are not included in the high resolution transmission (HITRAN) molecular absorption database of spectral lines. These parameters are required for developing a quantitative analytical method for measuring acrolein in a single puff of cigarette smoke using tunable diode laser absorption spectroscopy (TDLAS). The task is complex since acrolein has many highly overlapping infrared absorption lines in the room temperature spectrum and the cigarette smoke matrix contains thousands of compounds. This work describes the procedure for estimating the molecular line parameters for these overlapping absorption lines in the wavenumber range (958.7-958.9 cm(-1)) using quantitative reference spectra taken with the infrared lead-salt TDLAS instrument at different pressures and concentrations. The nitrogen broadened half-width for acrolein is 0.0937 cm(-1)atm(-1) and to our knowledge, is the first time it has been reported in the literature.

Determination of molecular parameters for 1,3-butadiene and propylene using infrared tunable diode laser absorption spectroscopy.

A technique has been developed for the determination of molecular parameters, including infrared absorption line positions, strengths, and nitrogen-broadened half-widths for 1,3-butadiene (C(4)H(6)) and propylene (C(3)H(6)). The parameters for these two molecules are required for quantitation using Tunable Diode Laser Absorption Spectroscopy (TDLAS). These molecules have populations of highly overlapping infrared absorption lines in their room temperature spectra. The technique reported here provides a procedure for estimating the molecular parameters for these overlapping absorption lines from quantitative reference spectra taken with the TDLAS instrument at different pressures and concentrations. The system was developed for the quantitation of gaseous constituents in a single puff of cigarette smoke and this paper will describe the procedure and some of the factors that influence the accuracy of quantitation for 1,3-butadiene, including the approach taken to minimize the adverse effects of the absorption due to propylene in the same spectral region.

Quad quantum cascade laser spectrometer with dual gas cells for the simultaneous analysis of mainstream and sidestream cigarette smoke.

A compact, fast response, infrared spectrometer using four pulsed quantum cascade (QC) lasers has been applied to the analysis of gases in mainstream (MS) and sidestream (SS) cigarette smoke. QC lasers have many advantages over the traditional lead-salt tunable diode lasers, including near room temperature operation with thermoelectric cooling and single mode operation with improved long-term stability. The new instrument uses two 36 m, 0.3 l multiple pass absorption gas cells to obtain a time response of 0.1s for the MS smoke system and 0.4s for the SS smoke system. The concentrations of ammonia, ethylene, nitric oxide, and carbon dioxide for three different reference cigarettes were measured simultaneously in MS and SS smoke. A data rate of 20Hz provides sufficient resolution to determine the concentration profiles during each 2s puff in the MS smoke. Concentration profiles before, during and after the puffs also have been observed for these smoke constituents in SS smoke. Also, simultaneous measurements of CO(2) from a non-dispersive infrared (NDIR) analyzer are obtained for both MS and SS smoke. In addition, during this work, nitrous oxide was detected in both the MS and SS smoke for all reference cigarettes studied.