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| Titel |
Dynamic Solution Injection: a new method for preparing pptv–ppbv standard atmospheres of volatile organic compounds |
| VerfasserIn |
K. J. Jardine, W. M. Henderson, T. E. Huxman, L. Abrell |
| 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 ; 3, no. 6 ; Nr. 3, no. 6 (2010-11-16), S.1569-1576 |
| Datensatznummer |
250001360
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| Publikation (Nr.) |
 copernicus.org/amt-3-1569-2010.pdf |
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| Zusammenfassung |
| Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and thermal desorption
Gas Chromatography-Mass Spectrometry (GC-MS) allow for absolute
quantification of a wide range of atmospheric volatile organic compounds
(VOCs) with concentrations in the ppbv to pptv range. Although often
neglected, routine calibration is necessary for accurate quantification of
VOCs by PTR-MS and GC-MS. Several gas calibration methods currently exist,
including compressed gas cylinders, permeation tubes, diffusion tubes, and
liquid injection. While each method has its advantages and limitations, no
single technique has emerged that is capable of dynamically generating known
concentrations of complex mixtures of VOCs over a large concentration range
(ppbv to pptv) and is technically simple, field portable, and affordable. We
present the development of a new VOC calibration technique based on liquid
injection with these features termed Dynamic Solution Injection (DSI). This
method consists of injecting VOCs (0.1–0.5 mM) dissolved in cyclohexane
(PTR-MS) or methanol (GC-MS) into a 1.0 slpm flow of purified dilution gas
in an unheated 25 ml glass vial. Upon changes in the injection flow rate
(0.5–4.0 μl min−1), new VOC concentrations are reached within
seconds to minutes, depending on the compound, with a liquid injection flow
rate accuracy and precision of better than 7% and 4% respectively. We
demonstrate the utility of the DSI technique by calibrating a PTR-MS to
seven different cyclohexane solutions containing a total of 34 different
biogenic compounds including volatile isoprenoids, oxygenated VOCs, fatty
acid oxidation products, aromatics, and dimethyl sulfide. We conclude that
because of its small size, low cost, and simplicity, the Dynamic Solution
Injection method will be of great use to both laboratory and field VOC
studies. |
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