Applied Physics B

, Volume 85, Issue 2, pp 257–263

High precision determinations of NH3 concentration by means of diode laser spectrometry at 2.005 μm


DOI: 10.1007/s00340-006-2322-y

Cite this article as:
De Tommasi, E., Casa, G. & Gianfrani, L. Appl. Phys. B (2006) 85: 257. doi:10.1007/s00340-006-2322-y


This paper reports on the development of a compact analyzer for ammonia monitoring in air, based on a distributed feedback diode laser at 2.005 μm. A dual-beam long-path technique was combined with wavelength modulation detection of absorption in order to reach a detection limit of about 25 ppb, with a 0.2-Hz equivalent noise bandwidth. Retrieval of NH3 concentration was accomplished through a careful spectra analysis procedure based on the formalism of Fourier expansion of the 2nd harmonic signals, also taking into account residual-amplitude-modulation effects. The system was tested on certified gas-mixtures and revealed a good performance in terms of accuracy and reproducibility. Particularly, the short-term precision was found to be about 1 ‰, for NH3 mixing ratios of 10 ppm. Finally, the possibility to make use of the analyzer for measurements of ammonia fluxes from soils is discussed.

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Dipartimento di Scienze Ambientali della Seconda Università di NapoliCNISM – Unità di Napoli 2CasertaItaly