Refinement of Compound Aromaticity in Complex Organic Mixtures by Stable Isotope Label Assisted Ultrahigh-Resolution Mass Spectrometry

Autor: Alexander Zherebker, Oliver J. Lechtenfeld, Yury Kostyukevich, Evgeny N. Nikolaev, Oleg N. Kharybin, Elena I. Fedoros, Anastasia Sarycheva
Rok vydání: 2020
Předmět:
Zdroj: Analytical Chemistry. 92:9032-9038
ISSN: 1520-6882
0003-2700
DOI: 10.1021/acs.analchem.0c01208
Popis: Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) provides a unique opportunity for molecular analysis of natural complex mixtures. In many geochemical and environmental studies structure-propertry relations are based solely on the elemental compositional information. Several calculated parameters were proposed to increase reliability of structural attribution, among which aromaticity indices (AI and AImod) are widely used. Herein, we applied a combination of selective labeling reactions in order to obtain direct structural information on the individual components of lignin-derived polyphenolic material. Carboxylic (COOH), carbonyl (C═O), and hydroxyl (OH) groups were enumerated by esterification, reducing, and acetylation reactions, respectively, followed by FTICR MS analyses. Obtained information was enabled to constrain aromaticity accounting for the carbon skeleton only. We found that actual aromaticity of components may be both higher or lower than approximated values depending on the abundance of COOH, C═O, and OH groups. The results are of importance for the geochemical community studying terrestrial NOM with structural gradients.
Databáze: OpenAIRE