Application Of A Polyethyleneimine Liquid Binding Layer For Measurement Of Co²⁺ With The Diffusive Gradients In Thin-Films Technique

The diffusive gradient in thin-films technique (DGT) incorporating an ion-combining phase separated from the solution by an ion-premeable gel membrane controls the ion diffusion in order to obtain quantitative analytical data in situ. This technique is not only overcoming the difficulty of the pretreatment but also combining the enrichment and the sampling. So the technique is very simple and fit for the measurement of trace metal ion in the water. Polyethyleneimine is used to do the binding layer and cellulose acetate dialysis membranes are used to do the diffusive layer in this thesis. And the concentration of Co2+ in the Hun He sample is determined.The experiment examined the interaction between the cellulose acetate dialysis membra--ne and the measured metal ions Co2+. The appropriate binding phase is 0.02mol/L. The maxi--m binding ability of 2.00 mL 0.02 mol/L Polyethyleneimine(PEI) is 2.5 mmol/L Co2+ in the solution. The binding ability of Co2+ and polyethyleneimine(PEI) was also measured at the di--fferent condition(pH, I). The diffusive coefficient of Co2+ is measured under different conc--entration of NaNO3.A lot of datum that the experiment obtained had directly demonstrated the presumption of determining the concentration of Co2+ in the Hun He sample with the cellulose acetate and the polyethyleneimine(PEI) is fit for the DGT technique.