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A versatile, refrigerant- and cryogen-free cryofocusing–thermodesorption unit for preconcentration of traces gases in air

Obersteiner, Florian ORCID iD icon; Bönisch, Harald 1; Keber, Timo; O& apos; Doherty, Simon; Engel, Andreas
1 Institut für Meteorologie und Klimaforschung (IMK), Karlsruher Institut für Technologie (KIT)


We present a compact and versatile cryofocusing– thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in situ measurements, in situ monitoring and laboratory operation for the analysis of flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. - 80° C) and subsequently desorbed by rapid heating of the adsorptive material (e.g. +200° C). The set-up involves neither the exchange of adsorption tubes nor any further condensation or refocusing steps. No moving parts are used that would require vacuum insulation. This allows for a simple and robust design. Reliable operation is ensured by the Stirling cooler, which neither contains a liquid refrigerant nor requires refilling a cryogen. At the same time, it allows for significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography – mass spectrometry (GC–MS) for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately -80 to +150° C and a substance mixing ratio range of less than 1 ppt (pmol mol$^{-1}$) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. ... mehr

Volltext §
DOI: 10.5445/IR/1000062443
DOI: 10.5194/amt-9-5265-2016
Zitationen: 9
Zitationen: 14
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Atmosphärische Spurenstoffe und Fernerkundung (IMK-ASF)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2016
Sprache Englisch
Identifikator ISSN: 1867-8548, 1867-1381
KITopen-ID: 1000062443
HGF-Programm 12.04.03 (POF III, LK 01) Stratospheric Ozone and Climate Change
Erschienen in Atmospheric measurement techniques
Verlag Copernicus Publications
Band 9
Heft 11
Seiten 5265–5279
Nachgewiesen in Web of Science
KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft
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