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Glöckler, D.* ; Harir, M. ; Schmitt-Kopplin, P. ; Elsner, M.* ; Bakkour, R.*

Discriminative behavior of cyclodextrin polymers against dissolved organic matter: Role of cavity size and sorbate properties.

Anal. Chem. 95, 14582-14591 (2023)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
Cyclodextrin polymers (CDPs) are promising next-generation adsorbents in water purification technologies. The selectivity of the polymer derivate cross-linked with tetrafluoroterephthalonitrile (TFN-CDP) for nonionic and cationic micropollutants (MPs) over dissolved organic matter (DOM) renders the adsorbent also attractive for many analytical applications. The molecular drivers of the observed selectivity are, nonetheless, not yet fully understood. To provide new insights into the sorption mechanism, we (i) synthesized TFN-CDPs with different cavity sizes (α-, β-, γ-CDP); (ii) assessed their extraction efficiencies for selected nonionic MPs in competition with different DOM size fractions (<1, 1-3, 3-10, >10 kDa) to test for size-selectivity; and (iii) performed nontargeted, ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry analysis on CDP-extracted DOM compounds (<1 kDa) to probe for molecular sorbate properties governing their selective sorption. First, no evidence of size-selectivity was obtained through either the different CD cavity sizes (i) or the two independent approaches (ii) and (iii). Second, we found a dominant impact of sorbate oxygenation and polarity on the extraction of DOM and MPs, respectively, with relatively oxygen-poor/nonpolar molecules favorably retained on all α-, β-, and γ-CDP. Third, our data indicates exclusion of an anionic matrix, such as carboxylic acids, but preferential sorption of cationic nitrogen-bearing DOM, pointing at repulsive and attractive forces with the negatively charged cross-linker as a likely reason. Therefore, we ascribe TFN-CDP's selectivity to nonpolar and electrostatic interactions between MPs/DOM and the polymer building blocks. These molecular insights can further aid in the optimization of efficient and selective sorbent design for environmental and analytical applications.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Solid-phase Extraction; Aqueous-solutions; Activated Carbon; Water; Micropollutants; River; Selectivity; Fluorine; Nitrogen; Dom
ISSN (print) / ISBN 0003-2700
e-ISSN 1520-6882
Quellenangaben Volume: 95, Issue: 39, Pages: 14582-14591 Article Number: , Supplement: ,
Publisher American Chemical Society (ACS)
Publishing Place 1155 16th St, Nw, Washington, Dc 20036 Usa
Non-patent literature Publications
Reviewing status Peer reviewed
Grants GermanResearch Foundation (DFG)