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Abstract No.: ThP-113
Session: Environmental Analysis
Presentation date: Thu, Aug 31, 2006
Presentation time: 09:50 – 11:20

Intercomparison of Oxygenated Organic Trace Gas Measurements

Armin Wisthaler1, Armin Hansel1, et al.2

1 Institut fuer Ionenphysik und Angewandte Physik, Innsbruck, Austria
2 ACCENT OVOC Intercomparison Team, various, various*

Correspondence address: Armin Wisthaler, Institut fuer Ionenphysik und Angewandte Physik, Leopold-Franzens-Universitaet Innsbruck, Technikerstrasse 25, Innsbruck, 6020 Austria.

Keywords: Ionization, Chemical; Mass Spectrometry, Field Portable; Real-Time Monitoring; Volatile Organic Analysis.

Novel aspect: A novel quality assurance test for oxygenated organic trace gas measurements is presented.

 

Volatile organic compounds (VOCs) are an important class of trace gases in air. Ongoing research on VOCs is being conducted in environmental sciences (photochemical ozone and particle formation, health effects, climate impact), in food science and technology (aroma release, markers for quality and process control) but increasingly also in the medical field (potential diagnostic markers in human breath). Oxygenated volatile organic compounds OVOCs (such as alcohols, ketones and aldehydes) are an important VOC subgroup which is, however, not routinely measured because of analytical problems mainly associated with sample alternation during pre-treatment for gas chromatographic (GC) analysis. In the past decade, a variety of methods has been developed for OVOC analysis ranging from sophisticated spectroscopic methods to improved GC-MS methods to direct mass spectrometric analysis using chemical ionization via ion-molecule reactions. Amongst them, Proton-Transfer-Reaction Mass Spectrometry developed at the Institute of Ion Physics in Innsbruck is a promising candidate allowing for on-line OVOC analysis at pptV (10-12 v/v) levels. In view of the absence of a standard method for OVOC analysis international comparability of results and quality assurance (QA) has been identified as a prioritary task within the European atmospheric science community. Thus, within the ACCENT (Atmospheric Composition Change The European Network of Excellence) QA Integration Task an experiment was carried out in the atmosphere simulation chamber SAPHIR at the Research Centre Jülich, Germany, to intercompare methods for OVOC measurements at ambient concentrations. 12 groups participated in this intercomparison with a variety of different instruments covering a broad range of methods. The intercomparison was conducted as a formal "blind" intercomparison with an independent referee. The compounds intercompared in this experiment were formaldehyde, acetaldehyde, butanal, hexanal, methanol, ethanol, 1-propanol, 1 butanol, methacrolein, methyl vinyl ketone, acetic acid methyl ester, acetone, benzaldehyde, and 2-methyl-3-buten-2-ol. The results of this activity, which confirm a superior PTR-MS performance, will be presented and discussed.