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Sans-Duñó J, Cecilia J, Galceran J, Puy J, Baeyens W, Gao Y. Back Accumulation of Diffusive Gradients in Thin-Films Devices with a Stack of Resin Discs To Assess Availability of Metal Cations to Biota in Natural Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7840-7848. [PMID: 37183959 DOI: 10.1021/acs.est.3c00799] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Determining species, concentrations, and physicochemical parameters in natural waters is key to improve our understanding of the functioning of these ecosystems. Diffusive Gradients in Thin-films (DGT) devices with different thicknesses of the resin or of the diffusive disc can be used to collect independent information on relevant parameters. In particular, DGT devices with a stack of two resin discs offer a simple way to determine dissociation rate constants of metal complexes from the accumulation of the target metal in the back resin disc. In this work, simple approximate expressions for the determination of the dissociation rate constant are reported and applied to a model Ni nitrilotriacetic complex as well as to Zn complexes in the Mediterranean Osor stream. Once the physicochemical parameters are known, one can plot the labile fraction of the metal complexes in terms of the thickness of the diffusion domain. These plots reveal a strong dependence on the nature of complexes as well as on the characteristics of the diffusion domain, and they are of high interest as predictors of availability to biota whose uptake is limited by diffusion.
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Affiliation(s)
- Jordi Sans-Duñó
- Departament de Química, Universitat de Lleida, and AGROTECNIO-CERCA, Rovira Roure 191, Lleida, Catalonia 25198, Spain
- Analytical, Environmental and Geochemical (AMGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels B-1050, Belgium
| | - Joan Cecilia
- Departament de Matemàtica, Universitat de Lleida, and AGROTECNIO-CERCA, Rovira Roure 191, Lleida, Catalonia 25198, Spain
| | - Josep Galceran
- Departament de Química, Universitat de Lleida, and AGROTECNIO-CERCA, Rovira Roure 191, Lleida, Catalonia 25198, Spain
| | - Jaume Puy
- Departament de Química, Universitat de Lleida, and AGROTECNIO-CERCA, Rovira Roure 191, Lleida, Catalonia 25198, Spain
| | - Willy Baeyens
- Analytical, Environmental and Geochemical (AMGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels B-1050, Belgium
| | - Yue Gao
- Analytical, Environmental and Geochemical (AMGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels B-1050, Belgium
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2
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Gorny J, Jardin C, Diez O, Galceran J, Gourgiotis A, Happel S, Coppin F, Février L, Simonucci C, Cazala C. Dissolved iodide in marine waters determined with Diffusive Gradients in Thin-films technique. Anal Chim Acta 2021; 1177:338790. [PMID: 34482898 DOI: 10.1016/j.aca.2021.338790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 06/15/2021] [Accepted: 06/20/2021] [Indexed: 10/21/2022]
Abstract
For the first time, Diffusive Gradient in Thin-films (DGT) focuses on the inorganic iodine species iodate (IO3-) and iodide (I-). A silver-doped Cl resin (AgdCl), which is known to selectively accumulate I-, was used to make a binding gel. Laboratory investigations were designed to verify the suitability of the AgdCl-DGT method to measure the total I- concentration in environmental waters. Total recovery of I- was obtained using an elution solution containing 100 mmol L-1 KCN. DGT validation experiments in 10 mmol L-1 NaCl showed linear accumulation of I- over time, contrary to IO3-, thus confirming the selectivity of AgdCl-binding gel. The AgdCl-DGT measurement of total I- concentration was independent of pH (4.5-8.8) and was not impacted by the presence of bicarbonate (1-5 mmol L-1). Finally, the performance of AgdCl-DGT samplers were tested in two continental waters and a synthetic seawater. The AgdCl-DGT samplers measured 27-33% of the total I- concentration in the two continental waters up to 24 h of deployment time, whereas the AgdCl-DGT response retrieved the total I- concentration in seawater up to 72 h (106 ± 7%). The difference in DGT response was attributed to the low ionic strength of the two continental waters, limiting the application of AgdCl-DGT method to media with higher ionic strength.
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Affiliation(s)
- Josselin Gorny
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SEDRE, LELI, Fontenay-aux-Roses, France.
| | - Cyrielle Jardin
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SEDRE, LELI, Fontenay-aux-Roses, France
| | - Olivier Diez
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SEDRE, LELI, Fontenay-aux-Roses, France
| | - Josep Galceran
- Departament de Química, Universitat de Lleida and AGROTECNIO-CERCA, Rovira Roure 191, 25198, Lleida, Spain
| | - Alkiviadis Gourgiotis
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SEDRE, LELI, Fontenay-aux-Roses, France
| | | | - Fréderic Coppin
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SRTE, LR2T, Cadarache, France
| | - Laureline Février
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SRTE, LR2T, Cadarache, France
| | - Caroline Simonucci
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SEDRE, LELI, Fontenay-aux-Roses, France; Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SIRSE, LER-NORD, France
| | - Charlotte Cazala
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV, SEDRE, LELI, Fontenay-aux-Roses, France
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Sans-Duñó J, Cecilia J, Galceran J, Puy J. Availability of metals to DGT devices with different configurations. The case of sequential Ni complexation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 779:146277. [PMID: 33744567 DOI: 10.1016/j.scitotenv.2021.146277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/27/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
The analytical technique DGT (Diffusive Gradients in Thin-films) is able to gain access to a wealth of information by carefully interpreting accumulation data from passive samplers with different configurations (i.e. different thicknesses of its constituent layers). A set of DGT devices were simultaneously deployed in solutions of Ni and nitrilotriacetic acid (NTA) of different concentrations to measure the availability of Ni in these solutions. Accumulations indicate that the availability of Ni depends on both the thickness of the resin and the thickness of the diffusive gel. In both cases, the lability degree increases as the thickness increases. As the formation of successive complexes (such as Ni(NTA)2) proceeds, the availability of the metal decreases, which is quantitatively explained by reducing the formulation to a case with only one complex, but with an effective dissociation rate constant that decreases as the concentration of NTA increases. Simple analytical expressions are reported to quantify the lability degree in the different DGT configurations. These results indicate that a set of different DGT devices can characterize the availability of a cation in a natural sample with uptake processes at different spatial or time scales. Alternatively, and from a more fundamental point of view, information on speciation, mobilities and labilities of the species present in natural samples can be obtained with a set of DGT configurations.
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Affiliation(s)
- Jordi Sans-Duñó
- Departament de Química, Universitat de Lleida and AGROTECNIO-CERCA, Rovira Roure 191, 25198 Lleida, Spain
| | - Joan Cecilia
- Departament de Matemàtica, Universitat de Lleida and AGROTECNIO-CERCA, Rovira Roure 191, 25198 Lleida, Spain
| | - Josep Galceran
- Departament de Química, Universitat de Lleida and AGROTECNIO-CERCA, Rovira Roure 191, 25198 Lleida, Spain
| | - Jaume Puy
- Departament de Química, Universitat de Lleida and AGROTECNIO-CERCA, Rovira Roure 191, 25198 Lleida, Spain.
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Cindrić AM, Marcinek S, Garnier C, Salaün P, Cukrov N, Oursel B, Lenoble V, Omanović D. Evaluation of diffusive gradients in thin films (DGT) technique for speciation of trace metals in estuarine waters - A multimethodological approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 721:137784. [PMID: 32172124 DOI: 10.1016/j.scitotenv.2020.137784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Understanding the potential bioavailability of trace metals (TM) in marine systems is of prime importance to implement adapted regulations and efficiently protect our coastal and estuarine waters. In this study Diffusive Gradients in Thin films (DGT) technique with two different pore size was used to evaluate the potentially bioavailable fractions (DGT-labile) of Cd, Co, Cu, Ni, Pb and Zn at various depths of a highly stratified estuary (the Krka River estuary, Croatia) both in winter and summer. DGT-labile concentrations were compared to (1) total dissolved concentrations, (2) concentrations of labile species measured by anodic stripping voltammetry (ASV-labile) for Cu and (3) concentrations derived by chemical speciation modelling. High correlation between dissolved and DGT-labile concentrations was found for all metals, except for Zn where contamination problems prevented reliable conclusions. Percentages of DGT-labile fractions over total dissolved concentrations were (AVG ± SD): 92 ± 3%, 64 ± 2%, 23 ± 5%, 61 ± 3% and 57 ± 6% for Cd, Pb, Cu, Ni and Co, respectively. No significant difference was found between trace metal concentrations measured with an open pore and restricted pore devices, implying the predominance of kinetically labile metal complexes smaller than 1 nm. For Cu, ASV-labile and DGT labile concentrations were highly correlated (0.97) with ASV-labile concentration being around 35% lower than that of the DGT-labile. Modelling of chemical speciation reliably predicted dynamic (free, inorganic and part of organic complexes) concentration of Cd, whereas dynamic concentrations of Cu and Pb were underestimated by 32% and 65%, respectively. In view of the relative simplicity of DGT devices, they are well suited for the monitoring effort of coastal waters, informing on potentially bioavailable concentrations of TM and thereby, helping to achieve good environmental status of coastal waters, as stipulated within the EU Water Framework Directive.
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Affiliation(s)
- Ana-Marija Cindrić
- Ruđer Bošković Institute, Center for Marine and Environmental Research, Bijenička 54, Zagreb, Croatia
| | - Saša Marcinek
- Ruđer Bošković Institute, Center for Marine and Environmental Research, Bijenička 54, Zagreb, Croatia
| | - Cédric Garnier
- Université de Toulon, Aix Marseille Université, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France
| | - Pascal Salaün
- Department of Earth and Ocean Sciences, University of Liverpool, Brownlow Street, Liverpool L69 3GP, UK
| | - Neven Cukrov
- Ruđer Bošković Institute, Center for Marine and Environmental Research, Bijenička 54, Zagreb, Croatia
| | - Benjamin Oursel
- Université de Toulon, Aix Marseille Université, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France
| | - Véronique Lenoble
- Université de Toulon, Aix Marseille Université, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France
| | - Dario Omanović
- Ruđer Bošković Institute, Center for Marine and Environmental Research, Bijenička 54, Zagreb, Croatia.
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Numerical Simulation of Non-Linear Models of Reaction—Diffusion for a DGT Sensor. ALGORITHMS 2020. [DOI: 10.3390/a13040098] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
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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6
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Time weighted average concentrations measured with Diffusive Gradients in Thin films (DGT). Anal Chim Acta 2019; 1060:114-124. [DOI: 10.1016/j.aca.2019.01.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/04/2019] [Accepted: 01/31/2019] [Indexed: 11/22/2022]
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Zhou C, van de Velde S, Baeyens W, Gao Y. Comparison of Chelex based resins in diffusive gradients in thin-film for high resolution assessment of metals. Talanta 2018; 186:397-405. [DOI: 10.1016/j.talanta.2018.04.085] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 11/29/2022]
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Jiménez-Piedrahita M, Altier A, Cecilia J, Puy J, Galceran J, Rey-Castro C, Zhang H, Davison W. Extending the Use of Diffusive Gradients in Thin Films (DGT) to Solutions Where Competition, Saturation, and Kinetic Effects Are Not Negligible. Anal Chem 2017; 89:6567-6574. [DOI: 10.1021/acs.analchem.7b00704] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | | | - Hao Zhang
- Lancaster
Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - William Davison
- Lancaster
Environment Centre, Lancaster University, Lancaster, United Kingdom
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9
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dos Anjos VE, Abate G, Grassi MT. Determination of labile species of As(V), Ba, Cd, Co, Cr(III), Cu, Mn, Ni, Pb, Sr, V(V), and Zn in natural waters using diffusive gradients in thin-film (DGT) devices modified with montmorillonite. Anal Bioanal Chem 2016; 409:1963-1972. [DOI: 10.1007/s00216-016-0144-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/05/2016] [Accepted: 12/09/2016] [Indexed: 11/27/2022]
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10
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Altier A, Jiménez-Piedrahita M, Rey-Castro C, Cecilia J, Galceran J, Puy J. Accumulation of Mg to Diffusive Gradients in Thin Films (DGT) Devices: Kinetic and Thermodynamic Effects of the Ionic Strength. Anal Chem 2016; 88:10245-10251. [PMID: 27660851 DOI: 10.1021/acs.analchem.6b02961] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Alexandra Altier
- Departament de Química and ‡Departament de Matemàtica, Universitat de Lleida and AGROTECNIO, Rovira Roure 191, 25198, Lleida, Spain
| | - Martín Jiménez-Piedrahita
- Departament de Química and ‡Departament de Matemàtica, Universitat de Lleida and AGROTECNIO, Rovira Roure 191, 25198, Lleida, Spain
| | - Carlos Rey-Castro
- Departament de Química and ‡Departament de Matemàtica, Universitat de Lleida and AGROTECNIO, Rovira Roure 191, 25198, Lleida, Spain
| | - Joan Cecilia
- Departament de Química and ‡Departament de Matemàtica, Universitat de Lleida and AGROTECNIO, Rovira Roure 191, 25198, Lleida, Spain
| | - Josep Galceran
- Departament de Química and ‡Departament de Matemàtica, Universitat de Lleida and AGROTECNIO, Rovira Roure 191, 25198, Lleida, Spain
| | - Jaume Puy
- Departament de Química and ‡Departament de Matemàtica, Universitat de Lleida and AGROTECNIO, Rovira Roure 191, 25198, Lleida, Spain
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11
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Laborda E, Olmos JM, Molina Á. Transfer of complexed and dissociated ionic species at soft interfaces: a voltammetric study of chemical kinetic and diffusional effects. Phys Chem Chem Phys 2016; 18:10158-72. [DOI: 10.1039/c6cp00780e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ACDT mechanism is considered in which two different ionic species of the same charge can be transferred across a soft interface while they interconvert each other through a homogeneous chemical reaction.
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Affiliation(s)
- Eduardo Laborda
- Departamento de Química Física
- Facultad de Química
- Regional Campus of International Excellence “Campus Mare Nostrum”
- Universidad de Murcia
- 30100 Murcia
| | - José Manuel Olmos
- Departamento de Química Física
- Facultad de Química
- Regional Campus of International Excellence “Campus Mare Nostrum”
- Universidad de Murcia
- 30100 Murcia
| | - Ángela Molina
- Departamento de Química Física
- Facultad de Química
- Regional Campus of International Excellence “Campus Mare Nostrum”
- Universidad de Murcia
- 30100 Murcia
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12
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Jiménez-Piedrahita M, Altier A, Cecilia J, Rey-Castro C, Galceran J, Puy J. Influence of the settling of the resin beads on diffusion gradients in thin films measurements. Anal Chim Acta 2015; 885:148-55. [PMID: 26231900 DOI: 10.1016/j.aca.2015.04.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/26/2015] [Accepted: 04/28/2015] [Indexed: 11/30/2022]
Abstract
Binding resin beads used in DGT (diffusion gradients in thin films) tend to settle to one side of the resin during casting. This phenomenon might be relevant for metal accumulation when partially labile complexes dominate the metal speciation, especially after recognizing the important role played by complex dissociation in the resin domain. The influence of the inhomogeneity of the binding agent distribution on metal accumulation is here assessed by numerical simulation of DGT devices with binding beads in only one half of the resin disc, as a reasonable model of the standard resin discs. Results indicate that a decrease in mass accumulation of less than 13% can arise in these inhomogeneous devices (as compared with an ideal disc with homogeneous dispersion of the resin beads) when complexes with stability constant K<10(2)m(3)mol(-1) (K<10(5)Lmol(-1)) dominate the metal speciation. The loss increases as K increases, but the percentage of mass loss always remains lower than the volume fraction of resin disc without beads. For very labile or inert complexes, the impact of the inhomogeneous distribution of binding resin beads is negligible. As kinetic dissociation constants of complexes can be estimated from the distribution of the metal accumulation in a DGT device with a stack of two resin discs, the influence of the inhomogeneity on the recovered kinetic constant is also assessed. For the cases studied, the recovered kinetic dissociation constant, kd,recovered, retains the correct order of magnitude, being related to the true kd by kd≈f(-1)kd,recovered, quite independently of K and kd values, being f the fraction of volume of the resin disc where resin beads are dispersed.
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Affiliation(s)
| | - Alexandra Altier
- Departament de Química,Universitat de Lleida and Agrotecnio, Rovira Roure 191, Lleida, 25198, Spain
| | - Joan Cecilia
- Departament de Matemàtica, Universitat de Lleida and Agrotecnio, Rovira Roure 191, 25198, Lleida, Spain
| | - Carlos Rey-Castro
- Departament de Química,Universitat de Lleida and Agrotecnio, Rovira Roure 191, Lleida, 25198, Spain
| | - Josep Galceran
- Departament de Química,Universitat de Lleida and Agrotecnio, Rovira Roure 191, Lleida, 25198, Spain
| | - Jaume Puy
- Departament de Química,Universitat de Lleida and Agrotecnio, Rovira Roure 191, Lleida, 25198, Spain.
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13
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Puy J, Galceran J, Cruz-González S, David CA, Uribe R, Lin C, Zhang H, Davison W. Measurement of Metals Using DGT: Impact of Ionic Strength and Kinetics of Dissociation of Complexes in the Resin Domain. Anal Chem 2014; 86:7740-8. [DOI: 10.1021/ac501679m] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jaume Puy
- Departament
de Química, Universitat de Lleida and AGROTECNIO, Rovira
Roure 191, 25198, Lleida, Spain
| | - Josep Galceran
- Departament
de Química, Universitat de Lleida and AGROTECNIO, Rovira
Roure 191, 25198, Lleida, Spain
| | - Sara Cruz-González
- Departament
de Química, Universitat de Lleida and AGROTECNIO, Rovira
Roure 191, 25198, Lleida, Spain
| | - Calin A. David
- Departament
de Química, Universitat de Lleida and AGROTECNIO, Rovira
Roure 191, 25198, Lleida, Spain
| | - Ramiro Uribe
- Departament
de Química, Universitat de Lleida and AGROTECNIO, Rovira
Roure 191, 25198, Lleida, Spain
- Departamento
de Física, Universidad del Tolima, Ibagué 730001, Colombia
| | - Chun Lin
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Hao Zhang
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - William Davison
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YW, United Kingdom
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14
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Mongin S, Uribe R, Rey-Castro C, Cecília J, Galceran J, Puy J. Limits of the linear accumulation regime of DGT sensors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:10438-10445. [PMID: 23944965 DOI: 10.1021/es400609y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A key question for the practical application of DGT (Diffusive Gradients in Thin films) as dynamic sensors in the environmental monitoring of trace metals is the influence of pH and dissolved ligands over the linear accumulation regime. Protons compete with metal ions for the binding to the DGT resin sites at relatively low pH, whereas high affinity dissolved ligands compete with resin sites for the binding of metals. Any of the two phenomena can lead to a departure from the linear accumulation regime and an underestimation of the actual species concentration in solution. These effects are studied here through numerical simulation of the diffusion-reaction processes in both gel and resin domains using a detailed chemical model of metal ions and protons interacting with resin sites. Results were tested successfully against experimental data of the Cd-NTA representative system. Charts to delimitate the range of experimental conditions (pH, ligand concentration and strength) where the linear accumulation regime prevails, can be helpful for designing sampling strategies in field conditions. For example, it is foreseen that perturbations of linear regime within 10 h of deployment are negligible above pH 5 and weak complexation (log K' < 0) or above pH 7 and strong complexation (log K' < 3), where K' is the effective stability constant. These plots can also be approximately used for partially labile systems whenever the time is replaced with the product lability degree times t.
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Affiliation(s)
- Sandrine Mongin
- Departament de Química and AGROTECNIO, ‡Departament de Matemàtica, ETSEA, Universitat de Lleida , Rovira Roure 191, 25198, Lleida, Spain
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15
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Shafaei Arvajeh MR, Lehto N, Garmo ØA, Zhang H. Kinetic studies of Ni organic complexes using diffusive gradients in thin films (DGT) with double binding layers and a dynamic numerical model. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:463-470. [PMID: 23153338 DOI: 10.1021/es301371b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In situ deployments of diffusive gradients in thin films (DGT) can provide direct information on complex dissociation rates in natural waters. Recent advances in understanding the dynamics of the interactions of metal complexes within DGT devices have highlighted the characteristics of the binding layer, but there are few data to complement these theoretical developments. In this work the penetration into the Chelex binding layer of complexes of Ni with nitrilotriacetic (NTA) and Suwannee River fulvic and humic acids (FA and HA) in solution at pH 7 was investigated by deployment of DGT devices with two sequential binding layers, a "front" and a "back" layer. In Ni-NTA experiments, the masses of Ni bound by the front and back binding layers were similar, as predicted for slowly dissociating complexes. For Ni-FA/HA solutions, a higher mass of Ni was taken up by the front binding layer, consistent with fast dissociation from a high proportion of the binding sites. The ratio of Ni in the front to back binding layers was significantly lower (p < 0.05) for solutions of Ni-HA compared to those of Ni-FA, indicating that Ni-HA complexes are less labile than Ni-FA complexes in similar solutions (FA = 10 mg L(-1) and HA = 8 mg L(-1)). A dynamic numerical model of the complexes in a DGT system was used to estimate the dissociation rate constants that provided the best agreement with the experimental data. Values obtained of 2 ± 0.5 × 10(-4) s(-1) for Ni-NTA and 2.5 × 10(-3) s(-1) for Ni-FA when FA = 20 mg L(-1) and 3.42 × 10(-4) s(-1) for Ni-HA when HA = 8 mg L(-1), could be rationalized with current knowledge of the dynamics of these systems. This approach can improve kinetic information obtainable using DGT and widen the range of considered complex labilities.
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Affiliation(s)
- M R Shafaei Arvajeh
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
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Puy J, Uribe R, Mongin S, Galceran J, Cecília J, Levy J, Zhang H, Davison W. Lability Criteria in Diffusive Gradients in Thin Films. J Phys Chem A 2012; 116:6564-73. [DOI: 10.1021/jp212629z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Ramiro Uribe
- Departamento
de Física, Universidad del Tolima, Ibagué, Colombia
| | | | | | | | - Jacqueline Levy
- Lancaster Environment
Centre, Lancaster University, Lancaster,
United Kingdom
| | - Hao Zhang
- Lancaster Environment
Centre, Lancaster University, Lancaster,
United Kingdom
| | - William Davison
- Lancaster Environment
Centre, Lancaster University, Lancaster,
United Kingdom
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Levy JL, Zhang H, Davison W, Galceran J, Puy J. Kinetic signatures of metals in the presence of Suwannee River fulvic acid. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3335-3342. [PMID: 22352943 DOI: 10.1021/es2043068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This work provides new information on the dissociation kinetics of metal-fulvic acid (FA) complexes. Diffusive gradients in thin-film (DGT) devices deployed in solutions containing metals and 30 mg L(-1) Suwannee River FA at pH 5 and 7, at two different metal-to-ligand ratios, were used to estimate an apparent diffusive boundary layer (ADBL) thickness at the gel-solution interface. The discrepancy between the ADBL thickness measured for metals that are known to dissociate from complexes quickly (e.g., Cd) and that of other trace metals was exploited to calculate the rate of complex dissociation. When the ADBL thickness is plotted for a suite of metals, a "kinetic signature" is created. There was a clear kinetic signature at pH 7, with substantial kinetic limitation for Cu, Pb, and Ni and none for Cd, Co, and Mn (i.e., Cu-, Pb-, and Ni-FA complexes dissociated more slowly). At pH 5, the kinetic signature was less distinct, due in part to slow association kinetics of Mn, and possibly Cd and Co, with the resin. The good sensitivity of the method to small changes in dissociation kinetics was able to show that the dissociation of most metal-FA complexes is sufficiently fast to not limit the DGT measurement.
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Affiliation(s)
- Jacqueline L Levy
- Lancaster Environment Centre, Lancaster University, Bailrigg LA1 4YW, United Kingdom.
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