An experimental setup for kinetic and product studies in a flow system has been developed. For detection, a nonresonant optoacoustic technique combined with a tunable lead-salt diode laser has been employed. The performance of the system was tested on ammonia in argon, and a detection limit (S/N = 2) of 8 × 1012 molecules cm−3 (corresponding to 320 ppb at atmospheric pressure) was obtained at a pressure of about 7 kPa when frequency modulation was employed. At 1.5 kPa the detection limit was about 2 × 1014 molecules cm−1. With a multipass cell the sensitivity was increased by a factor of four.
Finlayson-PittsB. J. and PittsJ. N., Atmospheric Chemistry: Fundamentals and Experimental Techniques (John Wiley and Sons, New York, 1986).
2.
JohnsonS. A., Anal. Proc.23, 1 (1986).
3.
SchiffH. I.HastieD. R.MackayG. I. and IguchiT, and RidleyB. A., Environ. Sci. Technol.17, 352A (1983).
4.
VansteenkisteT. H. and FaxvogF. R, and RoesslerD. M., Appl. Spectrosc.35, 194 (1981).
5.
StephanK. and HurdelbrinkW., “Line Strength Measurement Using Optoacoustic Spectroscopy”, in Monitoring Gaseous Pollutants by Tunable Diode Lasers, GrisarR.SchmidtkeG. and TackeM, and RestelliG., Eds. (Kluwer, Dordrecht, The Netherlands, 1989), p. 263.
6.
FehérM.RohrbacherA. and MaierJ. P, and MiklósA., Chem. Phys. Lett.211, 171 (1993).
7.
FehérM.JiangY. and MaierJ. P, and MiklósA., Appl. Opt.33, 1655 (1994).
8.
PoynterR. L. and MargolisJ. S., Molec. Phys.51, 393 (1984).
9.
KeyserL. F., J. Phys. Chem.88, 4750 (1984).
10.
DavidssonJ. and GutowH. J, and ZareN. R., J. Phys. Chem.94, 4069 (1990).
11.
GoldanP. D. and GotoK., J. Appl. Phys.45, 4350 (1974).
