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Optical properties of soil dissolved organic matter are related to acidic functions of its components as revealed by fractionation, selective deuteromethylation, and ultrahigh resolution mass spectrometryстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 8 апреля 2020 г.
- Авторы: Zherebker A., Shirshin E., Rubekina A., Kharybin O., Kononikhin A., Kulikova N.A., Zaitsev K.V., Roznyatovsky V.A., Grishin Yu K., Perminova I.V., Nikolaev E.N.
- Журнал: Environmental Science and Technology
- Том: 54
- Год издания: 2020
- Издательство: American Chemical Society
- Местоположение издательства: United States
- Первая страница: 2667
- Последняя страница: 2677
- DOI: 10.1021/acs.est.9b05298
- Аннотация: The goal of this study was to establish a relationship between the optical properties of soil dissolved organic matter (DOM) and acidic functions carried out by its individual constituents. We obtained 12 fractions of DOM samples using sequential solid phase extraction on nonionic sorbent at steadily lowered pH values: 7, 5, 3, 2, which correspond to low bounds of pKa values of phenols, aliphatic, and aromatic carboxylic acids, and ketoacids. The structural studies were conducted with the use of NMR and selective deuteromethylation of isolated fractions coupled to ultrahigh resolution mass spectrometry. First, a gradual shift of molecular compositions was observed from reduced components to aromatic oxidized compounds isolated at pH 7 and 2, respectively. Changes in molecular compositions were accompanied by a red shift of fluorescence spectra. Further application of deuteromethylation enabled us to distinguish DOM constituents with different amounts of carboxylic groups. Moreover, identification of structural isomers in a single DOM sample was achieved. Statistical analysis revealed that red shift of fluorescence is facilitated by the increase of a contribution of aromatic poly(carboxylic acid)s with high conjugation lengths. Additionally, analysis of the labeled fractionated permafrost thaw DOM directly showed carboxyl-rich alicyclic molecules, while the same components from lower-latitude DOM were assigned to lignin-like species.
- Добавил в систему: Куликова Наталья Александровна