Chinese Optics Letters, Vol. 5, Issue 11, 677 (2007)
Photoacoustic spectroscopy for fast and sensitive ammonia detection
Wang Zhang1,*, Zhiying Wu1, and Qingxu Yu2
- 1School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023
- 2Informational Engineering Department, Environmental Management College of China, Qinhuangdao 066004
A photoacoustic (PA) spectrometer with H-type first longitudinal resonant cells for ammonia detection is developed. A new PA cell structure is designed to accelerate the drift velocity of the sample gas near the cell surface, so that the short response time at the flow rate of 100 sccm (standard cubic centimeter per minute) is achieved. The response time of 5 min and detection limit of 0.86 ppbv is reached for ammonia concentration measurement with a Teflon polytetrafluoroethylene (PTFE) cell. Further improvement could be expected when using a brass cell with a high quality Teflon fluorinated ethylene propylene (FEP) coating.
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