Development and Performance of the Diffusive Gradients in Thin-Films Technique for the Measurement of Technetium-99 in Seawater

French, Megan; Zhang, Hao; Pates, Jacqueline M.; Bryan, S.; Wilson, Richard C.

doi:10.1021/ac048774b

Cited by 33 publications

(20 citation statements)

References 15 publications

(26 reference statements)

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“…[14,15] By using different binding agents the range of determinands has been extended from trace metals [16] to include other cations, [17,18] oxyanions [19,20] and targeted species, for example sulfide, [21] uranium, [22] radium [23] and technetium. [24] This burgeoning use of the technique in different areas of research has been facilitated by its simplicity, ease of use and the straightforward interpretation of measured mass (M DGT ) in terms of the DGT-labile concentration (C DGT ) which in sediments and soils is an interfacial concentration. [16,25] From the outset it was recognised that use of Eqn 1 to obtain C DGT from the well defined quantities (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics

2012

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Environmental context. It is now nearly 20 years since the introduction of the technique of diffusive gradients in thin films, which can provide information on solute concentrations and dynamics in sediments, soils and water. The interpretation of these measurements in terms of concentrations relies on simple equations and associated assumptions. This review examines how well they have stood the test of time.Abstract. Diffusive gradients in thin films (DGT) is now widely used to measure a range of determinands in waters, soils and sediments. In most cases the mass accumulated is interpreted in terms of a labile form of the component being measured using a simple equation that applies to steady-state conditions. During the past decade several publications have revealed phenomena that question some of the assumptions necessary for use of the simple equation. This review systematically examines the available evidence relating to appropriate geometry, possible charge effects, binding of solutes and ligands to the diffusive gel and filter, the rate of reaction with the binding layer, the effects of solution complexation and kinetic limitation, necessary time for deployment and the measurement of nanoparticles. DGT emerges as a robust monitoring tool for labile components in solution. Although there is evidence, for some conditions, of binding of metals and, more moderately, humic substances to the diffusive gel and filter membrane, this is unlikely to affect DGT measurement in natural waters for deployment times exceeding a few days. Detailed speciation and kinetic studies require a more thorough interpretation of the mass accumulated by DGT. A coherent theory has emerged for relatively simple solutions, but systems with complex heterogeneous ligands, as is the case for natural waters, are challenging. The size discrimination of DGT is still poorly known. Systematic measurements with well characterised nanoparticles are required to define the distribution of pore sizes in the gels and to establish the contribution of natural colloids to the DGT measurement.

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Section: Introductionmentioning

confidence: 99%

Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics

2012

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“…Several workers have used DGT with different resin sorbents (copper ferrocyanide [11] and ammonium molybdophosphate [8] for 133 Cs, 134 Cs and 137 Cs; TEVA ® resin for 99 Tc [12]; MnO 2 for Ra [13,14]) to measure radionuclides in natural waters. For the measurement of total U, DGT sorbent phases include Chelex-100 [9,[15][16][17], Whatman DE 81 [15], Metsorb TM (TiO 2 ) [9,[18][19][20] and Dowex resin [21].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of diffusive gradients in thin-films using a Diphonix® resin for monitoring dissolved uranium in natural waters

Turner

Mills

Burnett

et al. 2015

Analytica Chimica Acta

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Commercially available Diphonix(®) resin (TrisKem International) was evaluated as a receiving phase for use with the diffusive gradients in thin-films (DGT) passive sampler for measuring uranium. This resin has a high partition coefficient for actinides and is used in the nuclear industry. Other resins used as receiving phases with DGT for measuring uranium have been prone to saturation and significant chemical interferences. The performance of the device was evaluated in the laboratory and in field trials. In laboratory experiments uptake of uranium (all 100% efficiency) by the resin was unaffected by varying pH (4-9), ionic strength (0.01-1.00 M, as NaNO3) and varying aqueous concentrations of Ca(2+) (100-500 mg L(-1)) and HCO3(-) (100-500 mg L(-1)). Due to the high partition coefficient of Diphonex(®), several elution techniques for uranium were evaluated. The optimal eluent mixture was 1M NaOH/1M H2O2, eluting 90% of the uranium from the resin. Uptake of uranium was linear (R(2)=0.99) over time (5 days) in laboratory experiments using artificial freshwater showing no saturation effects of the resin. In field deployments (River Lambourn, UK) the devices quantitatively accumulated uranium for up to 7 days. In both studies uptake of uranium matched that theoretically predicted for the DGT. Similar experiments in seawater did not follow the DGT theoretical uptake and the Diphonix(®) appeared to be capacity limited and also affected by matrix interferences. Isotopes of uranium (U(235)/U(238)) were measured in both environments with a precision and accuracy of 1.6-2.2% and 1.2-1.4%, respectively. This initial study shows the potential of using Diphonix(®)-DGT for monitoring of uranium in the aquatic environment.

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“…A DGT-measured concentration to bulk solution concentration ratio (C DGT /C SOLN ) between 0.85 and 1.15 is considered to be indicative of adequate analyte recovery. 21 ' RESULTS AND DISCUSSION Uptake and Elution. The uptake efficiency of As III by mercapto-silica binding gels was >99%.…”

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Speciation of Dissolved Inorganic Arsenic by Diffusive Gradients in Thin Films: Selective Binding of As^III by 3-Mercaptopropyl-Functionalized Silica Gel

et al. 2011

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A diffusive gradients in thin films (DGT) technique for selectively measuring As(III) utilizes commercially available 3-mercaptopropyl-functionalized silica gel. Deployment of the new technique alongside the Metsorb-DGT for total inorganic arsenic allows the calculation of As(III) directly and As(V) by difference. Uptake of As(III) by mercapto-silica was quantitative and elution with a mixture of 1 mol L(-1) HNO(3) and 0.01 mol L(-1) KIO(3) gave a recovery of 85.6 ± 1.7%. DGT validation experiments showed linear accumulation of As(III) over time (R(2) > 0.998). Accumulation was unaffected by varying ionic strength (0.0001-0.75 mol L(-1) NaNO(3)) and pH (3.5-8.5). Deployment of mercapto-silica DGT and Metsorb DGT in seawater spiked with As(III) and As(V) demonstrated the ability of the combined approach to accurately quantify both species in the presence of potential competing ions. Ferrihydrite DGT, which has been previously reported for the measurement of total inorganic arsenic, was evaluated in seawater and shown to underestimate both As(III) and As(V) at longer deployment times (72 h). Reproducibility of the new mercapto-silica DGT technique was good (relative standard deviations < 9%), and the average method detection limit was sufficiently low to allow quantification of ultratrace concentrations of As(III) (0.03 μg L(-1); 72 h deployment).

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Development and Performance of the Diffusive Gradients in Thin-Films Technique for the Measurement of Technetium-99 in Seawater

Cited by 33 publications

References 15 publications

Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics

Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics

Evaluation of diffusive gradients in thin-films using a Diphonix® resin for monitoring dissolved uranium in natural waters

Speciation of Dissolved Inorganic Arsenic by Diffusive Gradients in Thin Films: Selective Binding of As^III by 3-Mercaptopropyl-Functionalized Silica Gel

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Development and Performance of the Diffusive Gradients in Thin-Films Technique for the Measurement of Technetium-99 in Seawater

Cited by 33 publications

References 15 publications

Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics

Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics

Evaluation of diffusive gradients in thin-films using a Diphonix® resin for monitoring dissolved uranium in natural waters

Speciation of Dissolved Inorganic Arsenic by Diffusive Gradients in Thin Films: Selective Binding of AsIII by 3-Mercaptopropyl-Functionalized Silica Gel

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Speciation of Dissolved Inorganic Arsenic by Diffusive Gradients in Thin Films: Selective Binding of As^III by 3-Mercaptopropyl-Functionalized Silica Gel