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An evaluation of DGT performance using a dynamic numerical model.

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An evaluation of DGT performance using a dynamic numerical model. / Lehto, Niklas J.; Davison, William; Zhang, Hao et al.

In: Environmental Science and Technology, Vol. 40, No. 20, 15.10.2006, p. 6368-6376.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

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Lehto NJ, Davison W, Zhang H, Tych W. An evaluation of DGT performance using a dynamic numerical model. Environmental Science and Technology. 2006 Oct 15;40(20):6368-6376. doi: 10.1021/es061215x

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Lehto, Niklas J. ; Davison, William ; Zhang, Hao et al. / An evaluation of DGT performance using a dynamic numerical model. In: Environmental Science and Technology. 2006 ; Vol. 40, No. 20. pp. 6368-6376.

Bibtex

@article{c82646e7bd6440538d282f82cbb94a11,
title = "An evaluation of DGT performance using a dynamic numerical model.",
abstract = "A numerical model of the transport and dynamics of metal complexes in the resin and gel layers of a DGT (diffusive gradients in thin films) device was developed and used to investigate how the chelating resin and metal-ligand complexes in solution affect metal uptake. Decreasing the stability constant or concentration of the binding resin increases the competition for free metal ions by ligands in solution, lowering the rate of mass uptake. Such effects would be rarely observed for moderately or strongly binding resins (K > 1012), including Chelex, which out-compete labile ligands in solution. With weakly binding resins, strongly bound solution complexes can diffuse into the resin layer before a measurable amount of dissociation occurs, such that concentrations of bound metal at the rear and front surfaces of the resin layer are equal. With more strongly binding resins, metal mainly binds to the front surface of the resin. Only complexes with the largest binding constants penetrate the gel layer containing Chelex, but their lack of lability means that the DGT sensitivity to the complex is, in any case, very low. The slow diffusion of complexes, such as those of fulvic acids, which increases the time required to establish steady state, compromises the use of the simple DGT equation. Errors are negligible for 24 h deployments, when diffusive layer thicknesses are less than 1 mm, but 3 day deployments are required to ensure accuracy with 2.4 mm thick layers. The extent to which the commonly used equation, that accounts for the concentration and diffusion of metal-complex species, overestimates DGT uptake if the rate of dissociation is slow, was estimated.",
author = "Lehto, {Niklas J.} and William Davison and Hao Zhang and Wlodek Tych",
year = "2006",
month = oct,
day = "15",
doi = "10.1021/es061215x",
language = "English",
volume = "40",
pages = "6368--6376",
journal = "Environmental Science and Technology",
issn = "0013-936X",
publisher = "American Chemical Society",
number = "20",

}

RIS

TY - JOUR

T1 - An evaluation of DGT performance using a dynamic numerical model.

AU - Lehto, Niklas J.

AU - Davison, William

AU - Zhang, Hao

AU - Tych, Wlodek

PY - 2006/10/15

Y1 - 2006/10/15

N2 - A numerical model of the transport and dynamics of metal complexes in the resin and gel layers of a DGT (diffusive gradients in thin films) device was developed and used to investigate how the chelating resin and metal-ligand complexes in solution affect metal uptake. Decreasing the stability constant or concentration of the binding resin increases the competition for free metal ions by ligands in solution, lowering the rate of mass uptake. Such effects would be rarely observed for moderately or strongly binding resins (K > 1012), including Chelex, which out-compete labile ligands in solution. With weakly binding resins, strongly bound solution complexes can diffuse into the resin layer before a measurable amount of dissociation occurs, such that concentrations of bound metal at the rear and front surfaces of the resin layer are equal. With more strongly binding resins, metal mainly binds to the front surface of the resin. Only complexes with the largest binding constants penetrate the gel layer containing Chelex, but their lack of lability means that the DGT sensitivity to the complex is, in any case, very low. The slow diffusion of complexes, such as those of fulvic acids, which increases the time required to establish steady state, compromises the use of the simple DGT equation. Errors are negligible for 24 h deployments, when diffusive layer thicknesses are less than 1 mm, but 3 day deployments are required to ensure accuracy with 2.4 mm thick layers. The extent to which the commonly used equation, that accounts for the concentration and diffusion of metal-complex species, overestimates DGT uptake if the rate of dissociation is slow, was estimated.

AB - A numerical model of the transport and dynamics of metal complexes in the resin and gel layers of a DGT (diffusive gradients in thin films) device was developed and used to investigate how the chelating resin and metal-ligand complexes in solution affect metal uptake. Decreasing the stability constant or concentration of the binding resin increases the competition for free metal ions by ligands in solution, lowering the rate of mass uptake. Such effects would be rarely observed for moderately or strongly binding resins (K > 1012), including Chelex, which out-compete labile ligands in solution. With weakly binding resins, strongly bound solution complexes can diffuse into the resin layer before a measurable amount of dissociation occurs, such that concentrations of bound metal at the rear and front surfaces of the resin layer are equal. With more strongly binding resins, metal mainly binds to the front surface of the resin. Only complexes with the largest binding constants penetrate the gel layer containing Chelex, but their lack of lability means that the DGT sensitivity to the complex is, in any case, very low. The slow diffusion of complexes, such as those of fulvic acids, which increases the time required to establish steady state, compromises the use of the simple DGT equation. Errors are negligible for 24 h deployments, when diffusive layer thicknesses are less than 1 mm, but 3 day deployments are required to ensure accuracy with 2.4 mm thick layers. The extent to which the commonly used equation, that accounts for the concentration and diffusion of metal-complex species, overestimates DGT uptake if the rate of dissociation is slow, was estimated.

U2 - 10.1021/es061215x

DO - 10.1021/es061215x

M3 - Journal article

VL - 40

SP - 6368

EP - 6376

JO - Environmental Science and Technology

JF - Environmental Science and Technology

SN - 0013-936X

IS - 20

ER -