Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)

Time weighted average (TWA) concentrations can improve the assessment of water quality. DGT (Diffusive Gradients in Thin films) devices have been suggested as simple tools to measure TWA metal concentrations, but the connection of TWA with C-DGT has not been rigorously discussed. It is shown here th...

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Autores: Altier Infantes, Alexandra, Jiménez-Piedrahita, Martín, Uribe Kaffure, Ramiro, Rey-Castro, Carlos, Galceran i Nogués, Josep, Puy Llorens, Jaume
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2019
País:España
Institución:Universitat de Lleida (UdL)
Repositorio:Repositori Obert UdL
OAI Identifier:oai:repositori.udl.cat:10459.1/66766
Acceso en línea:https://doi.org/10.1016/j.aca.2019.01.056
http://hdl.handle.net/10459.1/66766
Access Level:acceso abierto
Palabra clave:Passive sampling
Concentration fluctuation
Time average concentration
Lability degree
Transient effects
Complexation
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spelling Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)Altier Infantes, AlexandraJiménez-Piedrahita, MartínUribe Kaffure, RamiroRey-Castro, CarlosGalceran i Nogués, JosepPuy Llorens, JaumePassive samplingConcentration fluctuationTime average concentrationLability degreeTransient effectsComplexationTime weighted average (TWA) concentrations can improve the assessment of water quality. DGT (Diffusive Gradients in Thin films) devices have been suggested as simple tools to measure TWA metal concentrations, but the connection of TWA with C-DGT has not been rigorously discussed. It is shown here that C-DGT is the average DGT-labile concentration along the deployment, which suggests that it is well suited to correlate with toxicity effects. In terms of real species, C-DGT is a good estimator of the TWA concentration for simple metal solutions (no ligands are present) when the accumulation takes place under perfect sink conditions. Differences between CDGT and the TWA concentration for short pulses (<40 min), when the transient regime becomes relevant, are reported. In the presence of complexes, C-DGT contains the TWA of the product of the labile fraction times the diffusivity of the complex (relative to that of the free metal). This means that C-DGT can underestimate the TWA of the total metal concentration due to the presence of complexes less mobile than the free metal or not fully labile. These findings are illustrated with Cd, Ni, Mg or Ni + nitrilotriacetic acid (NTA) solutions. When only one complex is relevant, as in the Ni + NTA system, a simple correction factor can yield the TWA concentration from C-DGT.The authors gratefully acknowledge support for this research from the Spanish Ministry MCIU/AEI (Project CTM2016-78798) and FEDER UE (POCTEFA project EFA 183-16 OUTBIOTICS)Elsevier2019info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfhttps://doi.org/10.1016/j.aca.2019.01.056http://hdl.handle.net/10459.1/66766reponame:Repositori Obert UdL instname:Universitat de Lleida (UdL)Inglésinfo:eu-repo/grantAgreement/MINECO//CTM2016-78798Versió postprint del document publicat a: https://doi.org/10.1016/j.aca.2019.01.056Analytica Chimica Acta, 2019, vol. 1060, p. 114-124cc-by-nc-nd (c) Elsevier, 2019info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-nd/3.0/esoai:repositori.udl.cat:10459.1/667662026-06-24T12:42:17Z
dc.title.none.fl_str_mv Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
title Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
spellingShingle Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
Altier Infantes, Alexandra
Passive sampling
Concentration fluctuation
Time average concentration
Lability degree
Transient effects
Complexation
title_short Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
title_full Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
title_fullStr Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
title_full_unstemmed Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
title_sort Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT)
dc.creator.none.fl_str_mv Altier Infantes, Alexandra
Jiménez-Piedrahita, Martín
Uribe Kaffure, Ramiro
Rey-Castro, Carlos
Galceran i Nogués, Josep
Puy Llorens, Jaume
author Altier Infantes, Alexandra
author_facet Altier Infantes, Alexandra
Jiménez-Piedrahita, Martín
Uribe Kaffure, Ramiro
Rey-Castro, Carlos
Galceran i Nogués, Josep
Puy Llorens, Jaume
author_role author
author2 Jiménez-Piedrahita, Martín
Uribe Kaffure, Ramiro
Rey-Castro, Carlos
Galceran i Nogués, Josep
Puy Llorens, Jaume
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Passive sampling
Concentration fluctuation
Time average concentration
Lability degree
Transient effects
Complexation
topic Passive sampling
Concentration fluctuation
Time average concentration
Lability degree
Transient effects
Complexation
description Time weighted average (TWA) concentrations can improve the assessment of water quality. DGT (Diffusive Gradients in Thin films) devices have been suggested as simple tools to measure TWA metal concentrations, but the connection of TWA with C-DGT has not been rigorously discussed. It is shown here that C-DGT is the average DGT-labile concentration along the deployment, which suggests that it is well suited to correlate with toxicity effects. In terms of real species, C-DGT is a good estimator of the TWA concentration for simple metal solutions (no ligands are present) when the accumulation takes place under perfect sink conditions. Differences between CDGT and the TWA concentration for short pulses (<40 min), when the transient regime becomes relevant, are reported. In the presence of complexes, C-DGT contains the TWA of the product of the labile fraction times the diffusivity of the complex (relative to that of the free metal). This means that C-DGT can underestimate the TWA of the total metal concentration due to the presence of complexes less mobile than the free metal or not fully labile. These findings are illustrated with Cd, Ni, Mg or Ni + nitrilotriacetic acid (NTA) solutions. When only one complex is relevant, as in the Ni + NTA system, a simple correction factor can yield the TWA concentration from C-DGT.
publishDate 2019
dc.date.none.fl_str_mv 2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://doi.org/10.1016/j.aca.2019.01.056
http://hdl.handle.net/10459.1/66766
url https://doi.org/10.1016/j.aca.2019.01.056
http://hdl.handle.net/10459.1/66766
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/grantAgreement/MINECO//CTM2016-78798
Versió postprint del document publicat a: https://doi.org/10.1016/j.aca.2019.01.056
Analytica Chimica Acta, 2019, vol. 1060, p. 114-124
dc.rights.none.fl_str_mv cc-by-nc-nd (c) Elsevier, 2019
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es
rights_invalid_str_mv cc-by-nc-nd (c) Elsevier, 2019
http://creativecommons.org/licenses/by-nc-nd/3.0/es
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Repositori Obert UdL
instname:Universitat de Lleida (UdL)
instname_str Universitat de Lleida (UdL)
reponame_str Repositori Obert UdL
collection Repositori Obert UdL
repository.name.fl_str_mv
repository.mail.fl_str_mv
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