title: Key role of the resin layer thickness in the lability of complexes measured by DGT.
abstract: 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.
authors.affiliation: Departament de Química, Universitat de Lleida, Rovira Roure 191, 25198, Lleida, Spain.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Mongin
authors.forename: Ramiro
authors.initials: R
authors.lastname: Uribe
authors.forename: Jaume
authors.initials: J
authors.lastname: Puy
authors.forename: Joan
authors.initials: J
authors.lastname: Cecília
authors.forename: Josep
authors.initials: J
authors.lastname: Galceran
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: William
authors.initials: W
authors.lastname: Davison
mesh_terms: D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D004058:Diffusion; D007475:Ion Exchange Resins / Q000737:chemistry*; D008956:Models, Chemical; D009571:Nitrilotriacetic Acid / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D014867:Water / Q000032:analysis*
chemical_list: D007475:Ion Exchange Resins; D011137:Polystyrenes; D011145:Polyvinyls; D002104:Cadmium; D014867:Water; C006960:chelex; D009571:Nitrilotriacetic Acid