Evaluation of aliphatic/aromatic compounds and fluorophores in dissolved organic matter of contrasting natural waters by SEC-HPLC with multi-wavelength absorbance and fluorescence detections

Olga E Trubetskaya; Claire Richard; Svetlana V Patsaeva; Oleg A Trubetskoj

doi:10.1016/j.saa.2020.118450

Evaluation of aliphatic/aromatic compounds and fluorophores in dissolved organic matter of contrasting natural waters by SEC-HPLC with multi-wavelength absorbance and fluorescence detections

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Sep 5:238:118450. doi: 10.1016/j.saa.2020.118450. Epub 2020 May 5.

Authors

Olga E Trubetskaya¹, Claire Richard², Svetlana V Patsaeva³, Oleg A Trubetskoj⁴

Affiliations

¹ Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 142290 Pushchino, Moscow region, Russia.
² Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, Equipe Photochimie, BP 10448, F-63000 Clermont-Ferrand, France; CNRS, UMR 6296, ICCF, F-63171 Aubiere, France.
³ Faculty of Physics, Lomonosov Moscow State University, Moscow 119992, Russia.
⁴ Institute of Basic Biological Problems, Russian Academy of Sciences, 142290 Pushchino, Moscow region, Russia. Electronic address: olegi03@yahoo.com.

PMID: 32413721
DOI: 10.1016/j.saa.2020.118450

Abstract

The analytical high performance size exclusion liquid chromatography (SEC-HPLC) with multi-wavelength absorbance and fluorescence detections and fluorescence 3D-excitation/emission matrix (EEM) were used for the analysis of average molecular size (MS), molecular size distribution of aliphatic/aromatic compounds and fluorophores in dissolved organic matter (DOM) from Suwannee River (SRDOM) and two Karelian lakes (Vodoprovodnoe Lake - L1DOM and Onego Lake - L2DOM). The average MS of DOM samples varied in the order SRDOM > L1DOM > L2DOM. The absorbance ratios A250/A365 and A210/A254 have been used for the DOM samples characterization. The absorbance ratio A250/A365 provided significant information about average MS of the bulk aquatic DOMs but was not exactly correlated with the results of SEC-HPLC data. The absorbance ratio A210/A254 in combination with SEC was well correlated with the content of DOM aliphatic/aromatic compounds and could be used as an important water quality index to estimate the level of protein-like material in the aquatic DOM. Regardless of the origin (river or lakes), different geographical locations and different average MS of DOM, several similar types of humic-like SEC-separated fluorophores were found within the samples. In all DOM samples the decrease of the fluorophores emission maxima paralleled the decrease of their relative MS. The combination of SEC-HPLC with multi-wavelength fluorescence and absorbance detection and EEM analyses appears very useful for DOM characterization and for tracking of microbial activity resulting from anthropogenic and/or eutrophic impact in aquatic environments.

Keywords: Anthropogenic and eutrophic impact in aquatic environments; EEM fluorescence spectroscopy; Fluorophores and aliphatic/aromatic compounds distribution; High performance SEC with multi-wavelength absorbance and fluorescence detections; River and lakes dissolved organic matter (DOM).