High precision determinations of NH3 concentration by means of diode laser spectrometry at 2.005 mu m
Anno: 2006
Autori: De Tommasi E., Casa G., Gianfrani L.
Affiliazione autori: Seconda Università di Napoli, Dipartimento di Scienze Ambientali, Caserta, Italia;
CNISM, Unita Napoli 2, I-81100 Caserta, Italy
Abstract: 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 mu m. 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 parts per thousand, 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.
Giornale/Rivista: APPLIED PHYSICS B-LASERS AND OPTICS
Volume: 85 (2-3) Da Pagina: 257 A: 263
Parole chiavi: Semiconductor lasers, laser diodes; Laser spectroscopy; Analytical methods involving vibrationalDOI: 10.1007/s00340-006-2322-yCitazioni: 16dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-05-12Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui