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

Altier, Alexandra; Jiménez-Piedrahita, Martín; Uribe, Ramiro Restrepo; Rey-Castro, Carlos; Galceran, Josep; Puy, Jaume

doi:10.1016/j.aca.2019.01.056

Cited by 17 publications

(14 citation statements)

References 40 publications

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“…When transient effects are negligible and the deployment takes place under perfect-sink conditions (linear accumulation regime), it can be seen that c DGT corresponds to the timeweighted average of the labile concentration in the sample (Altier et al, 2019). This general result, together with the expression of c DGT in terms of the concentration of real species, Equation (3), leads to a general equation for the interpretation of c DGT in fluctuating systems.…”

Section: Dgt As a Time-weighted Average Concentrationmentioning

confidence: 86%

“…The integrative nature of DGT passive samplers suggests that they can provide timeweighted average (TWA) concentrations of the analytes over the deployment time, in contrast with conventional grab sampling (which yields a snapshot of the sampling site at one particular moment; Allan et al, 2007;Dunn et al, 2007;Huang et al, 2016Huang et al, , 2017. The response of DGT devices to changes in concentration during the deployment time has been studied both theoretically and experimentally through DGT deployments in solutions of different concentrations during controlled time periods (Altier et al, 2019). The results indicate that, if the duration of a pulsed fluctuation is much longer than the characteristic time to reach steady state (ca.…”

Section: Dgt As a Time-weighted Average Concentrationmentioning

confidence: 99%

“…Equation ( 20) allows to correct c DGT in order to obtain a better estimation of the metal concentration in the sample when the diffusion coefficient and the lability degree of the complex are known, as has been shown for the case of Ni in solutions with nitrilotriacetic acid (Altier et al, 2019).…”

Section: Dgt As a Time-weighted Average Concentrationmentioning

confidence: 99%

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

et al. 2021

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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.

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Section: Dgt As a Time-weighted Average Concentrationmentioning

confidence: 86%

Section: Dgt As a Time-weighted Average Concentrationmentioning

confidence: 99%

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

et al. 2021

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“…Using this algorithm, analysis of rigorous digital simulation of the diffusion-reaction processes in experimental accumulation by DGT sensors in several systems led to important theoretical developments related to DGT functioning [3,[17][18][19].…”

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confidence: 99%

Numerical Simulation of Non-Linear Models of Reaction—Diffusion for a DGT Sensor

2020

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In this work, we present a novel strategy for the numerical solution of a coupled system of partial differential equations that describe reaction–diffusion processes of a mixture of metals and ligands that can be absorbed by a sensor or a microorganism, in an aqueous medium. The novelty introduced in this work consisted of an adequate database management in conjunction with a direct iterative schema, which allowed the construction of simple, fast and efficient algorithms. Except in really adverse conditions, the calculation is converging and satisfactory solutions were reached. Computing times showed to be better than those obtained with some commercial programs. Although we concentrate on the solution for a particular system (Diffusive Gradients in Thin Films [DGT] sensors), the proposed algorithm does not require major modifications to consider new theoretical or experimental configurations. Since the quality of numerical simulations of reaction–diffusion problems often faces some drawbacks as the values of reaction rate constants increase, some additional effort has been invested in obtaining proper solutions in those cases.

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“…nitrate, iodide, Rb, etc. ), cDGT corresponds to the (time-averaged, [2]) total concentration of this species. For analytes (such as Cu) having different contributing forms (free Cu 2+ ions, inorganic complexes of copper such as hydroxides, organic Cu complexes with natural dissolved or colloidal organic matter, etc.…”

Section: Introductionmentioning

confidence: 99%

Developments in the diffusive gradients in thin-films technique for the speciation of oxyanions and platinum group elements in aquatic systems

Gao

Zhou

Galceran

et al. 2022

TrAC Trends in Analytical Chemistry

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Diffusive Gradients in Thin-films (DGT) is an in situ passive sampler with a widespread use in environmental studies. Within the ample range of analytes that can be probed with DGT, this review focuses on oxyanions and platinum group elements (PGEs). Ferrihydrite, zirconia, titanium dioxide and thiol-functionalized silica solid phases have been typically used as binding agents in DGT devices for oxyanions. DGT for PGEs had to overcome challenging interference problems during IPC-MS measurement of eluates, as well as slow equilibration kinetics in the bulk solution after spiking. This review summarizes the most recent analytical advances concerning the development and application of DGT with these target element groups, and points to the remaining knowledge gaps.

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

Abstract: Està subjecte a una llicència de Reconeixement-NoComercial-SenseObraDerivada 3.0 de Creative Commons

Cited by 17 publications

References 40 publications

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

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

Numerical Simulation of Non-Linear Models of Reaction—Diffusion for a DGT Sensor

Developments in the diffusive gradients in thin-films technique for the speciation of oxyanions and platinum group elements in aquatic systems

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