Key Role of the Resin Layer Thickness in the Lability of Complexes Measured by DGT

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• 作者：Sandrine Mongin ; Ramiro Uribe ; Jaume Puy ; Joan Cec铆lia ; Josep Galceran ; Hao Zhang ; William Davison
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：June 1, 2011
• 年：2011
• 卷：45
• 期：11
• 页码：4869-4875
• 全文大小：845K
• 年卷期：v.45,no.11(June 1, 2011)
• ISSN：1520-5851

文摘

Analysis of the dynamic features of diffusion gradients in thin film devices (DGT) indicates that the penetration of complexes into the resin layer dramatically increases their lability. This should be taken into account when interpreting DGT measurements in terms of the dynamics of solution speciation. The experimental accumulation of Cd by DGT sensors in Cd-NTA systems confirmed these theoretical analyses. A computational code, which allows a rigorous digital simulation of the diffusion-reaction processes in the gel and resin layers, was used to model the results and to demonstrate the effect of the complex penetration into the resin layer on the lability degree. These findings suggest that DGT renders all complexes much more labile than if the resin-diffusive gel interface was considered as a perfect planar sink, explaining why DGT often measures a high proportion of the metal in a natural water. This information is relevant since some studies have stressed the importance of labile complexes as a source of bioaccumulated metal.