Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer
Item
Title (Dublin Core)
Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer
Description (Dublin Core)
We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide (NO<sub>2</sub>) using cavity enhanced absorption spectroscopy with a broadband light source. The output of a Xenon arc lamp is coupled into a 1 m optical cavity, and the spectrum of light exiting the cavity is recorded by a grating spectrometer with a charge-coupled device (CCD) array detector. The mirror reflectivity and effective path lengths are determined from the known Rayleigh scattering of He and dry zero air (N<sub>2</sub>+O<sub>2</sub>). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, NO<sub>2</sub>, O<sub>4</sub>, and H<sub>2</sub>O in the 441 to 469 nm spectral range. For a 1-min sampling time, the precision (±1σ) on signal for measurements of CHOCHO and NO<sub>2</sub> is 29 pptv and 20 pptv, respectively. We directly compare measurements made with the incoherent broadband cavity enhanced absorption spectrometer with those from cavity ringdown instruments detecting CHOCHO and NO<sub>2</sub> at 404 and 532 nm, respectively, and find linear agreement over a wide range of concentrations. The instrument has been tested in the laboratory with both synthetic and real air samples, and the demonstrated sensitivity and specificity suggest a strong potential for field measurements of both CHOCHO and NO<sub>2</sub>.
Creator (Dublin Core)
Washenfelder, R. A.
Langford, A. O.
Fuchs, H.
Brown, S. S.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-8-7779-2008
https://acp.copernicus.org/articles/8/7779/2008/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
