Direct In Situ Measurements of Labile Inorganic and Organically Bound Metal Species in Synthetic Solutions and Natural Waters Using Diffusive Gradients in Thin Films

2000 ◽  
Vol 72 (18) ◽  
pp. 4447-4457 ◽  
Author(s):  
Hao Zhang ◽  
William Davison
Keyword(s):  
Thin Films ◽  
Natural Waters ◽  
In Situ Measurements ◽  
Metal Species ◽  
Diffusive Gradients

scholarly journals In Situ Measurement of Thallium in Natural Waters by a Technique Based on Diffusive Gradients in Thin Films Containing a δ-MnO2 Gel Layer

2018 ◽  
Vol 91 (2) ◽  
pp. 1344-1352 ◽  
Author(s):  
Hongmei Deng ◽  
Mengting Luo ◽  
Xinyao Shi ◽  
Paul N. Williams ◽  
Kexin Li ◽  
...  
Keyword(s):  
Thin Films ◽  
Natural Waters ◽  
In Situ Measurement ◽  
Gel Layer ◽  
Diffusive Gradients

Use of diffusive gradients in thin-films for studies of chemical speciation and bioavailability

2015 ◽  
Vol 12 (2) ◽  
pp. 85 ◽  
Author(s):  
Hao Zhang ◽  
William Davison
Keyword(s):  
Thin Films ◽  
Natural Waters ◽  
Chemical Speciation ◽  
Chemical Components ◽  
Measurement Tool ◽  
Response Curves ◽  
Predictive Tool ◽  
Environmental Chemical ◽  
Diffusive Gradients

Environmental context The health of aquatic organisms depends on the distribution of the dissolved forms of chemical components (speciation) and their rates of interaction (dynamics). This review documents and explains progress made using the dynamic technique of diffusive gradients in thin-films (DGT) to meet these challenges of measuring directly chemical speciation and associated dynamics in natural waters. The relevance of these measurements to uptake by biota of chemical forms in soils, sediments and water is discussed with reference to this expanding literature. Abstract This review assesses progress in studies of chemical speciation using diffusive gradients in thin-films (DGT) by examining the contributions made by key publications in the last 20 years. The theoretical appreciation of the dynamic solution components measured by DGT has provided an understanding of how DGT measures most metal complexes, but excludes most colloids. These findings strengthen the use of DGT as a monitoring tool and provide a framework for using DGT to obtain in situ kinetic information. Generally, the capabilities of DGT as an in situ perturbation and measurement tool have yet to be fully exploited. Studies that have used DGT to investigate processes relevant to bioavailability have blossomed in the last 10 years, especially for soils, as DGT mimics the diffusion limiting uptake conditions that, under some conditions, characterise uptake by plants. As relationships between element accumulated by DGT and in plants depend on the plant species, soils studied, and the element and its chemical form, DGT is not an infallible predictive tool. Rather its strength comes from providing information on the labile species in the system, whether water, soil or sediment. Recent studies have shown good relationships between measurements of metals in periphyton and by DGT, and unified dose response curves have been obtained for biota in sediments when they are based on DGT measurements. Both these cases suggest that alternative approaches to the established ‘free ion’ approach may be fruitful in these media and illustrate the growing use of DGT to investigate environmental chemical processes.

scholarly journals In situ speciation measurements. Using diffusive gradients in thin films (DGT) to determine inorganically and organically complexed metals

2001 ◽  
Vol 73 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Hao Zhang ◽  
William Davison
Keyword(s):  
Thin Films ◽  
Humic Substances ◽  
Natural Waters ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
High Concentrations ◽  
Gel Composition ◽  
Diffusive Gradients ◽  
Good Agreement

The possibilities of using diffusive gradients in thin films (DGT) and anodic stripping voltammetry (ASV) to perform speciation measurements in natural waters are discussed. Both techniques measure labile species, but different approaches have been used to discriminate organic (Corg) and inorganic (Cinorg) metal complexes. In DGT, metals are bound to a resin after passing through a hydrogel that serves as a well-defined diffusion layer. DGT devices with different hydrogels that impede the diffusion of humic substances by different amounts were deployed in solutions of copper and humic substances. Devices with a gel composition that greatly restricted the diffusion of humic substances, but only retarded the diffusion of Cu ions slightly, could be used directly to determine Cinorg. By using different, more open pored gels, which allowed some passage of humic substances, it was possible to determine both Corg and Cinorg. The two separate measurements of Cinorg obtained using the two DGT approaches agreed well. At the high concentrations of Cu used there was good agreement with the predicted distribution from the speciation code WHAM. At the lowest Cu concentration, the proportion of Cinorg estimated using DGT was higher than with WHAM. Possibilities of errors in the DGT or modeling approaches are discussed.

In-situ measurement of labile Cr(III) and Cr(VI) in water using diffusive gradients in thin-films (DGT)

2019 ◽  
Vol 653 ◽  
pp. 1161-1167 ◽  
Author(s):  
Li Gao ◽  
Bo Gao ◽  
Dongyu Xu ◽  
Ke Sun
Keyword(s):  
Thin Films ◽  
In Situ Measurement ◽  
Diffusive Gradients

scholarly journals Use of diffusive gradient in thin films for in situ measurements: A review on the progress in chemical fractionation, speciation and bioavailability of metals in waters

2017 ◽  
Vol 983 ◽  
pp. 54-66 ◽  
Author(s):  
Amauri Antonio Menegário ◽  
Lauren N. Marques Yabuki ◽  
Karen S. Luko ◽  
Paul N. Williams ◽  
Daniel M. Blackburn
Keyword(s):  
Thin Films ◽  
In Situ Measurements ◽  
Chemical Fractionation

In situ measurement of perfluoroalkyl substances in aquatic systems using diffusive gradients in thin-films technique

2018 ◽  
Vol 144 ◽  
pp. 162-171 ◽  
Author(s):  
Dong-Xing Guan ◽  
Ya-Qing Li ◽  
Nan-Yang Yu ◽  
Guang-Hui Yu ◽  
Si Wei ◽  
...  
Keyword(s):  
Thin Films ◽  
In Situ Measurement ◽  
Aquatic Systems ◽  
Perfluoroalkyl Substances ◽  
Diffusive Gradients
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