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| Titel |
Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer |
| VerfasserIn |
R. A. Washenfelder, A. O. Langford, H. Fuchs, S. S. Brown |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 24 ; Nr. 8, no. 24 (2008-12-23), S.7779-7793 |
| Datensatznummer |
250006533
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| Publikation (Nr.) |
 copernicus.org/acp-8-7779-2008.pdf |
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| Zusammenfassung |
| We describe an instrument for simultaneous measurements of glyoxal (CHOCHO)
and nitrogen dioxide (NO2) 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
(N2+O2). Least-squares fitting, using published reference
spectra, allow the simultaneous retrieval of CHOCHO, NO2, O4, and
H2O in the 441 to 469 nm spectral range. For a 1-min sampling time, the
precision (±1σ) on signal for measurements of CHOCHO and
NO2 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 NO2 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 NO2. |
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