Oligomers, organosulfates, and nitrooxy organosulfates in rainwater identified by ultra-high resolution electrospray ionization FT-ICR mass spectrometry K. E. Altieri1, B. J. Turpin2, and S. P. Seitzinger1,3 1Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA 2Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA 3Rutgers/NOAA CMER Program, Rutgers University, New Brunswick, NJ, USA
Abstract. Wet deposition is an important removal mechanism for atmospheric organic
matter, and a potentially important input for receiving ecosystems, yet less
than 50% of rainwater organic matter is considered chemically
characterized. Precipitation samples collected in New Jersey, USA, were
analyzed by negative ion ultra-high resolution electrospray ionization
Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).
Elemental compositions of 552 unique molecular species were determined in
the mass range 50–500 Da in the rainwater. Four main groups of organic
compounds were identified: compounds containing carbon, hydrogen, and oxygen
(CHO) only, sulfur (S) containing CHOS compounds, nitrogen (N) containing
CHON compounds, and S- and N- containing CHONS compounds. Organic acids
commonly identified in precipitation were detected in the rainwater. Within
the four main groups of compounds detected in the rainwater, oligomers,
organosulfates, and nitrooxy-organosulfates were assigned based on elemental
formula comparisons. The majority of the compounds identified are products
of atmospheric reactions and are known contributors to secondary organic
aerosol (SOA) formed from gas phase, aerosol phase, and in-cloud reactions
in the atmosphere. It is suggested that the large uncharacterized component
of SOA is the main contributor to the large uncharacterized component of
rainwater organic matter.
Citation: Altieri, K. E., Turpin, B. J., and Seitzinger, S. P.: Oligomers, organosulfates, and nitrooxy organosulfates in rainwater identified by ultra-high resolution electrospray ionization FT-ICR mass spectrometry, Atmos. Chem. Phys., 9, 2533-2542, doi:10.5194/acp-9-2533-2009, 2009.