Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1021/acs.est.1c04575
Document author version
Title (Primary) Aromaticity index with improved estimation of carboxyl group contribution for biogeochemical studies
Author Zherebker, A.; Rukhovich, G.D.; Sarycheva, A.; Lechtenfeld, O.J. ORCID logo ; Nikolaev, E.N.
Source Titel Environmental Science & Technology
Year 2022
Department ANA
Volume 56
Issue 4
Page From 2729
Page To 2737
Language englisch
Topic T9 Healthy Planet
Keywords NOM; humic substances; FTICR MS; carboxylic groups; aromaticity index; deuteromethylation; isotopic labeling
UFZ wide themes ProVIS;
Abstract Natural organic matter (NOM) components measured with ultrahigh-resolution mass spectrometry (UHRMS) are often assessed by molecular formula-based indices, particularly related to their aromaticity, which are further used as proxies to explain biogeochemical reactivity. An aromaticity index (AI) is calculated mostly with respect to carboxylic groups abundant in NOM. Here, we propose a new constrained AIcon based on the measured distribution of carboxylic groups among individual NOM components obtained by deuteromethylation and UHRMS. Applied to samples from diverse sources (coal, marine, peat, permafrost, blackwater river, and soil), the method revealed that the most probable number of carboxylic groups was two, which enabled to set a reference point n = 2 for carboxyl-accounted AIcon calculation. The examination of the proposed AIcon showed the smallest deviation to the experimentally determined index for all NOM samples under study as well as for individual natural compounds obtained from the Coconut database. In particular, AIcon performed better than AImod for all compound classes in which aromatic moieties are expected: aromatics, condensed aromatics, and unsaturated compounds. Therefore, AIcon referenced with two carboxyl groups is preferred over conventional AI and AImod for biogeochemical studies where the aromaticity of compounds is important to understand the transformations and fate of NOM compounds.
Persistent UFZ Identifier
Zherebker, A., Rukhovich, G.D., Sarycheva, A., Lechtenfeld, O.J., Nikolaev, E.N. (2022):
Aromaticity index with improved estimation of carboxyl group contribution for biogeochemical studies
Environ. Sci. Technol. 56 (4), 2729 - 2737 10.1021/acs.est.1c04575