Diffusive Gradients in Thin Films (DGT) Methodology for Selective and Spatially Discriminating Binding of Metal Ions

Metadata record for data from ASAC Project 2665 See the link below for public details on this project. The Antarctic environment with its harsh climatic conditions, minimal human activity and its unique ecosystems is unlike any of the World's other environments. As such, it is important that an understanding of the Antarctic environment is developed in order to gain a full appreciation of the impacts of human activities in Antarctica and to determine the most effective means to remediate and protect the Antarctic environment. To achieve these goals, new sensitive and selective techniques for sampling metal contaminant levels in marine sediments are being developed. The project is not an environmental study of the Antarctic environment (ie no metal concentrations in water or sediments), but rather the development of an analytical technique for use in Antarctica. We are still in the process of developing this technique and much of the development phase has involved qualitative assessment rather than generating quantitative data. We are currently trialling the technique in the lab and will conduct field trials in the Derwent Estuary. Taken from the abstract of the referenced paper: A novel binding phase was developed for use in diffusive gradients in thin-film (DGT) sampling for Cu(II) by employing methylthymol blue as a chelating and chromogenic agent. Methylthymol blue was adsorbed onto beads of Dowex 1x8 resin (200-400 mesh) and the resin beads were then immobilised onto an adhesive disc. Analysis of exposed binding discs by either UV-vis spectrophotometry or computer imaging densitometry provided robust quantification of adsorbed Cu(II) in the 0.2-1 micro gcm-2 range, allowing detection at micro gL-1 concentrations in the test solution (ca. 17 micro gL-1 for a 24 h deployment), and in good agreement with established DGT theory. The method was shown to be a potential replacement for binding phases based on Chelex 100 where a colorimetric response to a specific metal is desired.