In situ speciation of dissolved inorganic antimony in surface waters and sediment porewaters: development of a thiol-based diffusive gradients in thin films technique for SbIII

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Author(s)
Bennett, William W
Arsic, Maja
Welsh, David T
Teasdale, Peter R
Griffith University Author(s)
Year published
2016
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Antimony is a priority environmental contaminant typically present as either the trivalent (SbIII) or the pentavalent (SbV) oxidation state in aquatic systems. Both the toxicity and mobility of antimony are affected by its speciation, and thus the accurate measurement of antimony speciation is essential for investigating the behaviour of this contaminant in aquatic systems. Here we present a diffusive gradients in thin films (DGT) technique, which utilises a binding layer containing a thiol-based adsorbent (3-mercaptopropyl functionalised silica gel), for the selective measurement of SbIII in surface waters and sediment ...
View more >Antimony is a priority environmental contaminant typically present as either the trivalent (SbIII) or the pentavalent (SbV) oxidation state in aquatic systems. Both the toxicity and mobility of antimony are affected by its speciation, and thus the accurate measurement of antimony speciation is essential for investigating the behaviour of this contaminant in aquatic systems. Here we present a diffusive gradients in thin films (DGT) technique, which utilises a binding layer containing a thiol-based adsorbent (3-mercaptopropyl functionalised silica gel), for the selective measurement of SbIII in surface waters and sediment porewaters. We also evaluated the Metsorb DGT technique, which has been previously reported to accurately measure SbV, for its ability to accumulate SbIII and thus allow the measurement of total inorganic antimony. Both the mercapto-silica and Metsorb DGT techniques showed a high affinity for SbIII, with uptake efficiencies >97%. Elution efficiencies of 86.9 ± 2.6% and 88.1 ± 1.2% were obtained for mercapto-silica and Metsorb, respectively, with 1 mol L−1 H2O2 in 1 mol L−1 NaOH. The accumulation of SbIII by these DGT techniques was linear with time (R2 > 0.99) and unaffected by pH (4.07–8.05), ionic strength (0.001–1.0 mol L−1 NaCl), bicarbonate (1–15 mmol L−1), and an artificial seawater matrix (pH 8.34; salinity 34.8). Finally, the mercapto-silica DGT technique was applied to measure porewater concentrations of SbIII and AsIII in a contaminated freshwater sediment at high resolution.
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View more >Antimony is a priority environmental contaminant typically present as either the trivalent (SbIII) or the pentavalent (SbV) oxidation state in aquatic systems. Both the toxicity and mobility of antimony are affected by its speciation, and thus the accurate measurement of antimony speciation is essential for investigating the behaviour of this contaminant in aquatic systems. Here we present a diffusive gradients in thin films (DGT) technique, which utilises a binding layer containing a thiol-based adsorbent (3-mercaptopropyl functionalised silica gel), for the selective measurement of SbIII in surface waters and sediment porewaters. We also evaluated the Metsorb DGT technique, which has been previously reported to accurately measure SbV, for its ability to accumulate SbIII and thus allow the measurement of total inorganic antimony. Both the mercapto-silica and Metsorb DGT techniques showed a high affinity for SbIII, with uptake efficiencies >97%. Elution efficiencies of 86.9 ± 2.6% and 88.1 ± 1.2% were obtained for mercapto-silica and Metsorb, respectively, with 1 mol L−1 H2O2 in 1 mol L−1 NaOH. The accumulation of SbIII by these DGT techniques was linear with time (R2 > 0.99) and unaffected by pH (4.07–8.05), ionic strength (0.001–1.0 mol L−1 NaCl), bicarbonate (1–15 mmol L−1), and an artificial seawater matrix (pH 8.34; salinity 34.8). Finally, the mercapto-silica DGT technique was applied to measure porewater concentrations of SbIII and AsIII in a contaminated freshwater sediment at high resolution.
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Journal Title
Environmental Sciences: Processes and Impacts
Volume
18
Issue
8
Grant identifier(s)
DE140100056
Copyright Statement
© 2016 Royal Society of Chemistry. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. Please refer to the journal website for access to the definitive, published version.
Subject
Chemical sciences
Environmental sciences
Other environmental sciences not elsewhere classified
Biomedical and clinical sciences