Speciation of Inorganic Compounds in Aquatic Systems Using Diffusive Gradients in Thin-Films: A Review

Josep Galceran, Yue Gao, Jaume Puy, Martine Leermakers, Carlos Rey-Castro, Chunyang Zhou, Willy Baeyens

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4 Citations (Scopus)
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The speciation of trace metals in an aquatic system involves the determination of free ions, complexes (labile and non-labile), colloids, and the total dissolved concentration. In this paper, we review the integrated assessment of free ions and labile metal complexes using Diffusive Gradients in Thin-films (DGT), a dynamic speciation technique. The device consists of a diffusive hydrogel layer made of polyacrylamide, backed by a layer of resin (usually Chelex-100) for all trace metals except for Hg. The best results for Hg speciation are obtained with agarose as hydrogel and a thiol-based resin. The diffusive domain controls the diffusion flux of the metal ions and complexes to the resin, which strongly binds all free ions. By using DGT devices with different thicknesses of the diffusive or resin gels and exploiting expressions derived from kinetic models, one can determine the labile concentrations, mobilities, and labilities of different species of an element in an aquatic system. This procedure has been applied to the determination of the organic pool of trace metals in freshwaters or to the characterization of organic and inorganic complexes in sea waters. The concentrations that are obtained represent time-weighted averages (TWA) over the deployment period.
Original languageEnglish
Article number624511
Pages (from-to)1-18
Number of pages18
JournalFrontiers in Chemistry
Publication statusPublished - 6 Apr 2021

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Copyright © 2021 Galceran, Gao, Puy, Leermakers, Rey-Castro, Zhou and Baeyens.


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