Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer

Content Provider	Scilit
Author	Washenfelder, R. A. Langford, A. O. Fuchs, H. Brown, S. S.
Copyright Year	2008
Description	We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide $(NO_{2}$) 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 $(N_{2}+O_{2}$). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, $NO_{2}$, $O_{4}$, and $H_{2}$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 $NO_{2}$ 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 $NO_{2}$ 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 $NO_{2}$.
Ending Page	7793
Page Count	15
Starting Page	7779
DOI	10.5194/acpd-8-16517-2008
Alternate Webpage(s)	http://juser.fz-juelich.de/record/3832/files/acp-8-7779-2008.pdf
Issue Number	24
Volume Number	8
Language	English
Publisher	Copernicus GmbH
Publisher Date	2008-08-29
Access Restriction	Open
Subject Keyword	Incoherent Broadband Cavity Enhanced Absorption Spectrometer
Content Type	Text
Resource Type	Article