title: DGT/DET gel partition features of humic acid/metal species.
abstract: Gel layer based sensors are increasingly employed for dynamic trace metal speciation analysis in aquatic and soil media, in which humic and fulvic acid species are generally known to be relevant. In DGT (diffusive gradient in thin film), polyacrylamide hydrogels are commonly used for the diffusive gel layer. Various effects of the presence of humic species on the amount of metal detected by DGT have been observed, but the role of the different metal/humic species is still unknown. Recently it was shown that in the absence of metal, humic acid accumulates significantly in the polyacrylamide hydrogel. Here we analyze the extent of this accumulation in the presence of cadmium under various conditions of ionic strength and total humic and fulvic acid concentrations. At millimolar ionic strength level, DET data show significant accumulation of cadmium(II) in the gel phase, on top of some Donnan enrichment. The results are essential for the interpretation of DGT/DET data on metals in the presence of humics, especially in freshwaters.
authors.affiliation: Department of Physical Chemistry and Colloid Science, Wageningen University, Wageningen, The Netherlands. pascal.vanderveeken@wur.nl
authors.forename: Pascal L R van der
authors.initials: PL
authors.lastname: Veeken
authors.forename: Herman P van
authors.initials: HP
authors.lastname: Leeuwen
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D004058:Diffusion; D006812:Humic Substances / Q000032:analysis*; D008670:Metals / Q000737:chemistry*; D012987:Soil / Q000032:analysis; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D006812:Humic Substances; D008670:Metals; D012987:Soil; C016680:polyacrylamide gels; D014867:Water