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| Titel |
Non-Target Analyses of organic compounds in ice cores using HPLC-ESI-UHRMS |
| VerfasserIn |
Christoph Zuth, Christina Müller-Tautges, Anja Eichler, Margit Schwikowski, Thorsten Hoffmann |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250106259
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| Publikation (Nr.) |
 EGU/EGU2015-5921.pdf |
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| Zusammenfassung |
| To study the global climatic and environmental changes it is necessary to know the
environmental and especially atmospheric conditions of the past. By analysing climate
archives, such as for example ice cores, unique environmental information can be obtained. In
contrast to the well-established analysis of inorganic species in ice cores, organic
compounds have been analysed in ice cores to a much smaller extent. Because of
current analytical limitations it has become commonplace to focus on “total organic
carbon” measurements or specific classes of organic molecules, as no analytical
methods exist that can provide a broad characterization of the organic material
present[1]. On the one hand, it is important to focus on already known atmospheric
markers in ice cores and to quantify, where possible, in order to compare them
to current conditions. On the other hand, unfortunately a wealth of information
is lost when only a small fraction of the organic material is examined. However,
recent developments in mass spectrometry in respect to higher mass resolution and
mass accuracy enable a new approach to the analysis of complex environmental
samples.
The qualitative characterization of the complex mixture of water soluble organic carbon
(WSOC) in the ice using high-resolution mass spectrometry allows for novel insights
concerning the composition and possible sources of aerosol derived WSOC deposited at
glacier sites. By performing a non-target analysis of an ice core from the Swiss Alps using
previous enrichment by solid-phase extraction (SPE) and high performance liquid
chromatography coupled to electrospray ionization and ultra-high resolution mass
spectrometry (HPLC-ESI-UHRMS) 475 elemental formulas distributed onto 659 different
peaks were detected. The elemental formulas were classified according to their elemental
composition into CHO-, CHON-, CHOS-, CHONS-containing compounds and “others”.
Several methods for the analysis of complex data sets of high resolution mass spectrometry
were applied to the results of the non-target analysis. By various classifications in Van
Krevelen plots[2], amino acids and degradation products of proteins as well as degradation
products of lignins have been determined as the main components of the ice core.
Furthermore, the majority of WSOC molecular formulas identified in this non-target
analysis had molar H/C and O/C ratios similar to mono- and di-carboxylic acids
and SOAs[3]. Studies of the carbon oxidation state as a metric for describing the
chemistry of atmospheric organic aerosol showed that a majority of the elemental
formulas can be associated with the combustion of biomass as a major source of the
WSOC[4].
References:
[1] Grannas et al., J. Geophys Res.,2006, 111
[2] Sleighter, RL, Hatcher, PG, J. Mass Spectrom., 2007, 42, 559-574
[3] Wozniak et al., Atmos. Chem. Phys., 2008, 8, 5099-5111
[4] Kroll et al., Nature Chemistry, 2011, 3, 133-139 |
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