Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 6 5 2006 10.5194/acpd-6-10247-2006 http://www.atmos-chem-phys-discuss.net/6/10247/2006/ http://www.atmos-chem-phys-discuss.net/6/10247/2006/acpd-6-10247-2006.html http://www.atmos-chem-phys-discuss.net/6/10247/2006/acpd-6-10247-2006.pdf 10247 10274 2006-10-12 Performance of Chemical Ionization Reaction Time-of-Flight Mass Spectrometry (CIR-TOF-MS) for the measurement of atmospherically significant oxygenated volatile organic compounds K. P. Wyche R. S. Blake A. M. Ellis P. S. Monks T. Brauers R. Koppmann E. Apel Department of Chemistry, University of Leicester, Leicester, UK Institut für Chemie und Dynamik der Geosphäre II, Forschungszentrum Jülich, Jülich, Germany National Centre for Atmospheric Research, Boulder, CO, USA now at: Bergische Universität Wuppertal, Fachbereich C, Atmosphärenphysik, Wuppertal, Germany The performance of a new chemical ionization reaction time-of-flight mass spectrometer (CIR-TOF-MS) utilising the environment chamber SAPHIR (Simulation of Atmospheric Photochemistry In a large Reaction Chamber – Forschungzentrum Jülich, Germany) is described. The work took place as part of the ACCENT (Atmospheric Composition and Change the European NeTwork for excellence) supported oxygenated volatile organic compound (OVOC) measurement intercomparison during January 2005. The experiment entailed the measurement of 14 different atmospherically significant OVOCs at various mixing ratios in the approximate range 10.0–0.6 ppbV. The CIR-TOF-MS operated throughout the exercise with the hydronium ion (H₃O⁺) as the primary chemical ionization (CI) reagent in order to facilitate proton transfer to the analyte OVOCs. The results show the CIR time-of-flight mass spectrometer is capable of detecting a wide range of atmospheric OVOCs down to sub-ppbV mixing ratios with high accuracy and precision. It is demonstrated that the technique has rapid multi-channel response at the required sensitivity, accuracy and precision for atmospheric OVOC measurements.