Technika DGT a její použití pro speciační měření v přírodních vodách

Application of DGT technique for speciation measurement in natural waters

conference paper

Czech

Trace metals are measured after accumulation them on a selective binding resin (Chelex-100) after passage through a diffusive polyacrylamide gel of known thickness by DGT (Diffusive gradient in thin films) technique. Metals are continuously removed from solution to the resin in the DGT unit. The concentration of metals in solution is consequently calculated from the mass of metals accumulated in resin during a known time and exposed area. The DGT unit measures the only part of metals available to bind to resin, it means ions and kinetically labile complexes with natural ligands, which can dissociate in the time needed to the diffusion through the gel analogous to ASV measurement. The time available for dissociation of complexes is determinate by the diffusive gel layer thickness. By change of diffusive gel thickness it is possible to determinate which species will be measured according to metal-ligand stability. More accurate speciation measurements can be performed by simultaneously application of two DGT devices one fitted with an open-pore diffusive gel and the other with a partially restricted one. The usage of DGT units fitted with gels of different magnitude of pores allowed separation of large (organic) and small (inorganic) complexes. DGT technique offers many advantages over conventionally used speciation methods. It presents an in situ, very simple, multielementary and preconcentration technique, which can be successfully used for metal speciation in aqueous systems.

DGT

DGT, species, natural waters

DIVIŠ, P., DOČEKALOVÁ, H.

15. 10. 2003

2Theta

Český Těšín

80-86380-20-3

Mikroelementy 2003

94

97

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