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

Altier Infantes, Alexandra; Jiménez-Piedrahita, Martín; Uribe Kaffure, Ramiro; Rey Castro, Carlos; Galceran i Nogués, Josep; Puy Llorens, Jaume

doi:https://doi.org/10.1016/j.aca.2019.01.056

View/Open

Postprint (1.253Mb)

Issue date

2019-07-04

Author

Altier Infantes, Alexandra

Jiménez-Piedrahita, Martín

Uribe Kaffure, Ramiro

Rey Castro, Carlos

Galceran i Nogués, Josep

Puy Llorens, Jaume

Suggested citation

Altier Infantes, Alexandra; Jiménez-Piedrahita, Martín; Uribe Kaffure, Ramiro; Rey Castro, Carlos; Galceran i Nogués, Josep; Puy Llorens, Jaume; . (2019) . Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT). Analytica Chimica Acta, 2019, vol. 1060, p. 114-124. https://doi.org/10.1016/j.aca.2019.01.056.

Abstract

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.

URI

http://hdl.handle.net/10459.1/66766

DOI

https://doi.org/10.1016/j.aca.2019.01.056

Is part of

Analytica Chimica Acta, 2019, vol. 1060, p. 114-124

Collections

Publicacions de projectes de recerca del Plan Nacional [2429]
Articles publicats (Agrotecnio Center) [1043]
Articles publicats (Química) [273]

The following license files are associated with this item:

Creative Commons

Except where otherwise noted, this item's license is described as cc-by-nc-nd (c) Elsevier, 2019