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dc.contributor.authorAltier Infantes, Alexandra
dc.contributor.authorJiménez-Piedrahita, Martín
dc.contributor.authorRey Castro, Carlos
dc.contributor.authorCecilia Averós, Joan
dc.contributor.authorGalceran i Nogués, Josep
dc.contributor.authorPuy Llorens, Jaume
dc.date.accessioned2017-04-05T10:10:18Z
dc.date.available2017-09-23T22:22:51Z
dc.date.issued2016-09-23
dc.identifier.issn0003-2700
dc.identifier.urihttp://hdl.handle.net/10459.1/59461
dc.description.abstractAvailability of magnesium is a matter of concern due to its role in many environmental and biological processes. Diffusive Gradients in Thin Films (DGT) devices can measure Mg availability in situ. This work shows that Mg accumulation in water largely increases when ionic strength (I) decreases. This phenomenon can be explained from (i) the increase of both the association equilibrium (K) and rate (ka,R) constants for the reaction between Mg cations and resin sites, and (ii) the growing contribution of the partitioning of Mg cations at the resin–gel interface, as I decreases. Two theoretical models that take into account electrical interactions among Mg cations, background electrolyte, and resin sites can successfully be used to determine ka,R and K at each I. Both models yield similar ka,R values, which fulfill an expression for the kinetic salt effect. For freshwater (with a typical salinity of 10 mM and circumneutral pH), the binding of Mg is so fast and strong that the simplest perfect-sink DGT expression can be helpful to predict (overestimation lower than 5%) the accumulation in solutions with Mg concentrations up to 1 mM whenever the deployment time is below 9 h. Perfect sink conditions can still be applied for longer times, in systems with either a lower I or a lower Mg concentration.
dc.description.sponsorshipFinancial support from FEDER and the Spanish Ministry of Education and Science (Projects CTM2012-39183 and CTM2013-48967) is gratefully acknowledged.
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.publisherAmerican Chemical Society
dc.relationMICINN/PN2008-2011/CTM2012-39183
dc.relationMINECO/PN2013-2016/CTM2013-48967
dc.relation.isformatofVersió postprint del document publicat a: https://doi.org/10.1021/acs.analchem.6b02961
dc.relation.ispartofAnalytical Chemistry, 2016, vol. 88, núm. 20, p. 10245-10251
dc.rights(c) American Chemical Society, 2016
dc.subject.otherFisicoquímica
dc.subject.otherTermodinàmica
dc.titleAccumulation of Mg to Diffusive Gradients in Thin Films (DGT) devices: Kinetic and thermodynamic effects of the ionic strength
dc.typeinfo:eu-repo/semantics/article
dc.date.updated2017-04-05T10:10:20Z
dc.identifier.idgrec024852
dc.type.versioninfo:eu-repo/semantics/acceptedVersion
dc.rights.accessRightsinfo:eu-repo/semantics/openAccess
dc.identifier.doihttps://doi.org/10.1021/acs.analchem.6b02961


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