NitroEurope - or NEU for short - is a project for integrated European research into the nitrogen cycle. NitroEurope is part of the EU's Sixth Framework Programme for Research and Technological Development, and will run for 5 years from February 2006 until 2011.
Ammonia monitoring at ppb level using photoacoustic spectroscopy for environmental application
Submitted by Laszlo_Horvath on Mon, 19/01/2009 - 11:05.
Publication Type:
Journal Paper (published)Source:
Sensors and Actuators B, Elsevier, Volume 134, p.1027-1033 (2008)Abstract:
A novel photoacoustic (PA) trace-ammonia analyzer for measuring ambient ammonia concentration in the lower ppb concentration range has been developed. It is based on a wavelength-modulated, telecommunication type, room temperature-operated diode laser light source, an acoustically optimized, longitudinal resonator type small volume photoacoustic cell and a compact multi-functional electronics unit, which ensures the fully automatic long-term operation of the system. It has a response time below 2 min, which is achieved by using a photoacoustic cell made of polyvinylidene fluoride (PVDF) and gas-handling tubes made of polyamide 11 (PA-11). A dual wavelength measurement method with optimized measurement wavelengths and laser modulation parameters was introduced, which proved to efficiently suppress cross-sensitivity to other atmospheric components, most importantly to water vapor, while improving the sensitivity of the system. The developed PA system was tested with reference to a continuous-flow denuder system (AMANDA) under both laboratory and simulated field conditions, and it featured highly reliable, fully automatic operation with a detection limit of about 50 ppb of ammonia. (C) 2008 Elsevier B.V. All rights reserved.
