Technical Note: Performance of Chemical Ionization Reaction Time-of-Flight Mass Spectrometry (CIR-TOF-MS) for the measurement of atmospherically significant oxygenated volatile organic compounds

[摘要] The performance of a new chemical ionization reaction time-of-flightmass spectrometer (CIR-TOF-MS) utilising the environment chamberSAPHIR (Simulation of Atmospheric Photochemistry In a large ReactionChamber- Forschungzentrum Jülich, Germany) is described. Thework took place as part of the ACCENT (Atmospheric Composition andChange the European NeTwork for excellence) supported oxygenatedvolatile organic compound (OVOC) measurement intercomparison duringJanuary 2005. The experiment entailed the measurement of 14different atmospherically significant OVOCs at various mixing ratiosin the approximate range 10.0–0.6 ppbV. The CIR-TOF-MS operatedthroughout the exercise with the hydronium ion (H₃O⁺) asthe primary chemical ionization (CI) reagent in order to facilitateproton transfer to the analyte OVOCs. The results presented showthat the CIR time-of-flight mass spectrometer is capable ofdetecting a wide range of atmospheric OVOCs at mixing ratios ofaround 10 ppbV in "real-time" (i.e. detection on the one-minute timescale), with sub-ppbV measurement also achieved following anincrease in averaging time to tens of minutes.It is shown that ingeneral OVOC measurement is made with high accuracy and precision,with integration time, mixing ratio and compound dependent values asgood as 4–13% and 3–15% respectively.It is demonstratedthat CIR-TOF-MS has rapid multi-channel response at the requiredsensitivity, accuracy and precision for atmospheric OVOCmeasurement.

[学科分类] 大气科学