Title

Molecular Characterization of Dissolved Black Nitrogen via Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Authors

Sasha Wagner, Southeast Environmental Research Center and Department of Chemistry and Biochemistry, Florida International UniversityFollow
Thorsten Dittman, University of Oldenburg
Rudolf Jaffe´, Southeast Environmental Research Center, Department of Chemistry and Biochemistry, Florida International University,Follow

Abstract

Combustion produces a complex mixture of polycondensed aromatic compounds known as black carbon (BC). Such products can become remobilized from char and soil in the form of dissolved BC (DBC). Ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI–FT-ICRMS) analysis of a variety of soil and char leachates showed that a significant proportion of DBC compounds contained one or more nitrogen atoms. While the presence of black nitrogen (DBN) in dissolved organic matter (DOM) has been reported, its molecular features were uncharacterized. Here we present results of FT-ICRMS characterization of DBN, where assigned formulae were validated on the basis on their ¹³C isotope signatures and fragmentation patterns obtained via collision induced dissociation. Possible chemical structures were assigned for several DBN formulae and suggest that nitrogen was incorporated into the core ring system as a pyrrole-type moiety. Most DBN compounds existed as part of homologous series where homologs differed by a mass corresponding to CO₂, suggesting that they were polysubstituted with carboxylic acid groups. The environmental contribution of such novel, aromatic, combustion-derived nitrogen compounds with respect to global nitrogen cycling remains elusive. The biogeochemical implications of the input of such fire-derived products to aquatic ecosystems as part of climate change therefore need to be assessed.

Comments

Copyright © 2014 Elsevier Ltd. All rights reserved.

DOI: http://dx.doi.org/10.1016/j.orggeochem.2014.12.002

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DEB-1237517, #DBI-0620409, and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Wagner, S., T. Dittmar, R. Jaffe. 2015. Molecular characterization of dissolved black nitrogen by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Organic Geochemistry 79: 21-30. DOI: 10.1016/j.orggeochem.2014.12.002