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| Titel |
A smog chamber comparison of a microfluidic derivatisation measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques |
| VerfasserIn |
X. Pang, A. C. Lewis, A. R. Rickard, M. T. Baeza-Romero, T. J. Adams, S. M. Ball, M. J. S. Daniels, I. C. A. Goodall, P. S. Monks, S. Peppe, M. Ródenas García, P. Sanchez, A. Muñoz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 2 ; Nr. 7, no. 2 (2014-02-03), S.373-389 |
| Datensatznummer |
250115592
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| Publikation (Nr.) |
 copernicus.org/amt-7-373-2014.pdf |
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| Zusammenfassung |
| A microfluidic lab-on-a-chip derivatisation technique has been developed to
measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and
methylglyoxal (MGLY), and the method is compared with other techniques in a
smog chamber experiment. The method uses o-(2, 3, 4, 5, 6-pentafluorobenzyl)
hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated
planar glass micro-reactor comprising an inlet, gas and fluid splitting and
combining channels, mixing junctions, and a heated capillary reaction
microchannel. The enhanced phase contact area-to-volume ratio and the high
heat transfer rate in the micro-reactor resulted in a fast and highly
efficient derivatisation reaction, generating an effluent stream ready for
direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A
linear response for GLY was observed over a calibration range 0.7 to 400 ppbV,
and for MGLY of 1.2 to 300 ppbV, when derivatised under optimal
reaction conditions. The analytical performance shows good accuracy (6.6% for GLY and 7.5% for MGLY), suitable precision (<12.0%)
with method detection limits (MDLs) of 75 pptV for GLY and 185 pptV
for MGLY, with a time resolution of 30 min. These MDLs are below or
close to typical concentrations of these compounds observed in ambient air.
The feasibility of the technique was assessed by applying the methodology to
quantify α-dicarbonyls formed during the photo-oxidation of
isoprene in the EUPHORE chamber. Good correlations were found between
microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR)
with a correlation coefficient (r2) of 0.84, Broadband Cavity Enhanced
Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro
extraction (SPME) (r2 = 0.89), and a photochemical chamber box
modelling calculation (r2 = 0.79) for GLY measurements. For MGLY
measurements, the microfluidic technique showed good agreement with BBCEAS
(r2 = 0.87), SPME (r2 = 0.76), and the modeling simulation
(r2 = 0.83), FTIR (r2 = 0.72) but displayed a discrepancy with
Proton-Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) with
r2 value of 0.39. |
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