Abstract. The sources and atmospheric chemistry of gas-phase organic acids are
currently poorly understood, due in part to the limited range of measurement
techniques available. In this work, we evaluated the use of SF6-
as a sensitive and selective chemical ionization reagent ion for real-time
measurements of gas-phase organic acids. Field measurements are made using
chemical ionization mass spectrometry (CIMS) at a rural site in Yorkville,
Georgia, from September to October 2016 to investigate the capability of this
measurement technique. Our measurements demonstrate that SF6-
can be used to measure a range of organic acids in the atmosphere. One-hour
averaged ambient concentrations of organic acids ranged from a few parts per
trillion by volume (ppt) to several parts per billion by volume (ppb). All
the organic acids displayed similar strong diurnal behaviors, reaching
maximum concentrations between 17:00 and 19:00 EDT. The organic acid
concentrations are dependent on ambient temperature, with higher organic acid
concentrations being measured during warmer periods.
Non-radioactive Chemical Ionization Mass Spectrometry Using Acetic Acid–Acetate Cluster as a Reagent Ion for the Real-time Measurement of Acids and Hydroperoxides
