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Nontarget analysis of Murchison soluble organic matter by high-field NMR spectroscopy and FTICR mass spectrometry.
Magn. Reson. Chem. 53, 754-768 (2015)
High-field NMR spectra of Murchison meteorite methanolic extracts revealed primarily aliphatic extraterrestrial organic matter (EOM) with near statistical branching of commonly C3-5 units separated by heteroatoms and aromatic units. The ratios of CCH, OCH and Csp2 H units were 89 : 8 : 3, whereas carbon-based aliphatic chain termination was in the order methyl > COOH > CH(CH3 )COOH. Aliphatic methine carbon was abundant, but its weak NMR signatures were primarily deduced from JRES (J-resolved) NMR spectra. Carbon NMR spectra were dominated by methylene and methyl carbon; strong apodization revealed methine carbon, of which about 20% was aromatic. Extrapolation provided 5-7% aromatic carbon present in Murchison soluble EOM. Compositional heterogeneity in Murchison methanolic extracts was visible in NMR and Fourier transform ion cyclotron (FTICR) mass spectra obtained from a few cubic millimeters of solid Murchison meteorite; increasing sample size enhanced uniformity of NMR spectra. Intrinsic chemical diversity and pH-dependent chemical shift variance contributed to the disparity of NMR spectra. FTICR mass spectra provided distinct clustering of CHO/CHOS and CHNO/CHNOS molecular series and confirmed the prevalence of aliphatic/alicyclic (73%) over single aromatic (21%) and polyaromatic (6%) molecular compositions, suggesting extensive aliphatic substitution of aromatic units as proposed by NMR. Murchison soluble EOM molecules feature a center with enhanced aromatic and heteroatom content, which provides rather diffuse and weak NMR signatures resulting from a huge overall chemical diversity. The periphery of Murchison EOM molecules comprises flexible branched aliphatic chains and aliphatic carboxylic acids. These project on narrow ranges of chemical shift, facilitating observation in one-dimensional and two-dimensional NMR spectra. The conformational entropy provided by these flexible surface moieties facilitates the solubility of EOM.
Impact Factor
Scopus SNIP
Web of Science
Times Cited
Times Cited
Scopus
Cited By
Cited By
Altmetric
1.179
0.581
30
30
Anmerkungen
Besondere Publikation
Auf Hompepage verbergern
Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
13c ; 1h ; Eom ; Fticr Mass Spectra ; Murchison ; Nmr ; Composition ; Conformational Entropy ; Molecular Diversity ; Organic Matter; Magnetic-resonance-spectroscopy; Aqueous Alteration; Early Earth; Meteorite; Evolution; Orgueil; C-13; Molecules; Aerosols; Fraction
Sprache
englisch
Veröffentlichungsjahr
2015
HGF-Berichtsjahr
2015
ISSN (print) / ISBN
0749-1581
e-ISSN
1097-458X
Zeitschrift
Magnetic Resonance in Chemistry
Quellenangaben
Band: 53,
Heft: 9,
Seiten: 754-768
Verlag
Wiley
Verlagsort
Chichester
Begutachtungsstatus
Peer reviewed
POF Topic(s)
30202 - Environmental Health
Forschungsfeld(er)
Environmental Sciences
PSP-Element(e)
G-504800-001
PubMed ID
26275226
DOI
10.1002/mrc.4249
WOS ID
WOS:000359803000016
Scopus ID
84939222312
Erfassungsdatum
2015-08-16