Molecular characterization of dissolved black nitrogen via electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

TitleMolecular characterization of dissolved black nitrogen via electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry
Publication TypeJournal Article
Year of Publication2015
AuthorsWagner, S, Allred, SRB, Dittmar, T, Jaffé, R
JournalOrganic Geochemistry
Volume79
Pagination21 - 30
Date Published2015/02//
ISBN Number0146-6380
KeywordsBlack carbon, Black nitrogen, Charcoal, Collision induced dissociation fragmentation, Dissolved organic matter, Electrospray ionization, Fire, FT-ICRMS, Molecular characterization, soil
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.

URLhttp://www.sciencedirect.com/science/article/pii/S0146638014002927
Short TitleOrganic Geochemistry