Insights into dissolved organic matter complexity in rainwater from continental and coastal storms by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry 1Department of Chemistry and Biochemistry University of North Carolina, Wilmington, NC 28403-5932, USA
14 May 2013
2National High Magnetic Field Laboratory 1800 East Paul Dirac Dr., Tallahassee, FL 32310-4005, USA
Received: 24 October 2012 – Published in Atmos. Chem. Phys. Discuss.: 06 December 2012 Abstract. A series of seven rainwater samples were collected in Wilmington, North
Carolina USA originating from both continental and coastal storms and
analyzed by ultrahigh resolution Fourier transform ion cyclotron resonance
mass spectrometry (FT-ICR MS). This data set is unique in that it represents
a detailed comparison of the molecular level composition of DOM in rainwater
collected from distinctly different air mass back trajectories by FT-ICR MS.
Approximately 25% of the roughly 2000 assigned CHO molecular formulas are
unique to a single storm classification indicating the importance of air mass
back trajectory on the composition of rainwater dissolved organic matter
(DOM). Analysis of the unique molecular formula assignments highlighted
distinct groupings of various bio- and geo-molecule classes with coastal
storms containing unique formulas representative of lignin and cellulose-like
formulas while continental storms had lipid-like formulas. A series of 18
distinct methylene oligomers were identified in coastal storms and 13 unique
methylene oligomers in continental storms, suggesting oligomer formation is
ubiquitous in rainwater albeit different for each storm classification.
Oligomers of small acids and C3H4O2 were detected in both
storm types indicating their processing may be similar in both back
trajectories. Condensed aromatic hydrocarbons were detected in continental
storms with phenol moieties that are not as oxidized as similar compounds
detected in aquatic DOM.
Revised: 09 April 2013 – Accepted: 13 April 2013 – Published: 14 May 2013
Citation: Mead, R. N., Mullaugh, K. M., Brooks Avery, G., Kieber, R. J., Willey, J. D., and Podgorski, D. C.: Insights into dissolved organic matter complexity in rainwater from continental and coastal storms by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry, Atmos. Chem. Phys., 13, 4829-4838, doi:10.5194/acp-13-4829-2013, 2013.