Applied Physics B

, Volume 77, Issue 4, pp 381–385

Ultra-sensitive ambient ammonia detection using CO2-laser-based photoacoustic spectroscopy

Rapid communication

DOI: 10.1007/s00340-003-1266-8

Cite this article as:
Pushkarsky, M., Webber, M. & Patel, C. Appl. Phys. B (2003) 77: 381. doi:10.1007/s00340-003-1266-8


An ambient trace-ammonia sensor that uses resonant photoacoustic spectroscopy and a line-tunable CO2 laser has been developed. This system achieves a 1σ replicate precision of 32 parts-per-trillion (ppt) with an averaging time of 5 s and a total measurement time of 40 s. This 32-ppt precision corresponds to a minimum detectable fractional absorbance of 8.8×10-9, a minimum detectable absorption coefficient of 9.6×10-10 cm-1, and a minimum path-length-normalized detectivity of 1.1×10-8 W cm-1/Hz1/2. Background interference from CO2, H2O, and cell-window absorption were subtracted by switching to a neighboring off-resonance laser wavelength .

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Pranalytica, Inc. Santa MonicaUSA

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