Solid-Phase Extraction of Aquatic Organic Matter: Loading-Dependent Chemical Fractionation and Self-Assembly

Dissolved organic matter (DOM) is an important component in marine and freshwater environments and plays a fundamental role in global biogeochemical cycles. In the past, optical and molecular-level analytical techniques evolved and improved our mechanistic understanding about DOM fluxes. For most mo...

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Bibliographic Details
Published in:Environmental science & technology 2021-11, Vol.55 (22), p.15495-15504
Main Authors: Kong, Xianyu, Jendrossek, Thomas, Ludwichowski, Kai-Uwe, Marx, Ute, Koch, Boris P
Format: Article
Language:English
Subjects:
Adsorption
Biogeochemical cycles
Biogeochemical Cycling
Biogeochemistry
Chemical fractionation
Desalination
Dissolved organic carbon
Dissolved organic matter
Divinylbenzene
Extraction procedures
Fluorescence
Fractionation
Freshwater environments
Multilayers
Polymers
Self-assembly
Solid phases
Sorbents
Styrene
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Summary:Dissolved organic matter (DOM) is an important component in marine and freshwater environments and plays a fundamental role in global biogeochemical cycles. In the past, optical and molecular-level analytical techniques evolved and improved our mechanistic understanding about DOM fluxes. For most molecular chemical techniques, sample desalting and enrichment is a prerequisite. Solid-phase extraction has been widely applied for concentrating and desalting DOM. The major aim of this study was to constrain the influence of sorbent loading on the composition of DOM extracts. Here, we show that increased loading resulted in reduced extraction efficiencies of dissolved organic carbon (DOC), fluorescence and absorbance, and polar organic substances. Loading-dependent optical and chemical fractionation induced by the altered adsorption characteristics of the sorbent surface (styrene divinylbenzene polymer) and increased multilayer adsorption (DOM self-assembly) can fundamentally affect biogeochemical interpretations, such as the source of organic matter. Online fluorescence monitoring of the permeate flow allowed to empirically model the extraction process and to assess the degree of variability introduced by changing the sorbent loading in the extraction procedure. Our study emphasizes that it is crucial for sample comparison to keep the relative DOC loading (DOCload [wt %]) on the sorbent always similar to avoid chemical fractionation.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.1c04535