Ambient measurements of amines and related nitrogen-containing compounds in a rural environment using protonated ethanol chemical ionization high-resolution mass spectrometry

 
Poster PDF

Authors

Harald Stark — Aerodyne Research, Inc.
John B Nowak — Aerodyne Research, Inc.
Aroob Abdelhamid — University of Colorado
Eleanor Browne — University of Colorado
Joel K Kimmel — Aerodyne Research, Inc./Tofwerk
Roy Leon Mauldin — University of Colorado, Boulder
James Smith — University of California, Irvine
Rod Soper — Southern Great Plains
John R Schatz — ARM Climate Research Facility
John T Jayne — Aerodyne Research, Inc.
Douglas R Worsnop — Aerodyne Research, Inc.

Category

General topics – Aerosols

Description

Ammonia and amines are important atmospheric constituents that originate from biogenic and anthropogenic processes. Their tropospheric mixing ratios are expected to be very low, often in the sub-pptv levels and poorly known. Even at these extremely low levels, they can be important for atmospheric nucleation processes, often as basic counterparts to sulfuric acid, and can also serve as reducing agents in the otherwise oxidative troposphere. Their atmospheric fate is largely unknown; it is expected that they can be converted to other compounds through atmospheric oxidation, with unknown formation timescales, mechanisms, and products. In this SBIR Phase II project, we have deveoped an ethanol-CIMS technique that uses chemical ionization by protonated ethanol ions and detection by a a high-resolution time-of-flight mass spectrometer. We present field measurements from the HISCALE campaign that took place at the ARM-SGP site in Billings, Oklahoma, in August and September of 2016. We report measurements of ammonia, amines, amides, imides, urea, and other reduced nitrogen-containing compounds with ethanol-CIMS. The time resolution and detection limits of this instrument are improved compared to previously used techniques. Further, the high-resolution mass spectra allow formula assignment to ions related to new compounds that have not been known to exist in the atmosphere and investigate their temporal behavior, which can help in understanding the atmospheric fate of reduced nitrogen compounds. This work was supported by Award No. DE-SC0011218.