Adam W. Birdsall1, Ulrich K. Krieger2, and Frank N. Keutsch1,3
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
2Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zurich, Switzerland
3School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
Received: 19 Sep 2017 – Discussion started: 21 Sep 2017
Revised: 17 Nov 2017 – Accepted: 24 Nov 2017 – Published: 08 Jan 2018
Abstract. New analytical techniques are needed to improve our understanding of the intertwined physical and chemical processes that affect the composition of aerosol particles in the Earth's atmosphere, such as gas–particle partitioning and homogenous or heterogeneous chemistry, and their ultimate relation to air quality and climate. We describe a new laboratory setup that couples an electrodynamic balance (EDB) to a mass spectrometer (MS). The EDB stores a single laboratory-generated particle in an electric field under atmospheric conditions for an arbitrarily long length of time. The particle is then transferred via gas flow to an ionization region that vaporizes and ionizes the analyte molecules before MS measurement. We demonstrate the feasibility of the technique by tracking evaporation of polyethylene glycol molecules and finding agreement with a kinetic model. Fitting data to the kinetic model also allows determination of vapor pressures to within a factor of 2. This EDB–MS system can be used to study fundamental chemical and physical processes involving particles that are difficult to isolate and study with other techniques. The results of such measurements can be used to improve our understanding of atmospheric particles.
Citation:
Birdsall, A. W., Krieger, U. K., and Keutsch, F. N.: Electrodynamic balance–mass spectrometry of single particles as a new platform for atmospheric chemistry research, Atmos. Meas. Tech., 11, 33-47, https://doi.org/10.5194/amt-11-33-2018, 2018.