The invention relates to a DTPA modified material and a preparation method for a rapid-full-dissociation type DGT (Diffusive gradients in thin films)
coupling phase prepared therefrom. DTPA reacts with Mg<2+> and Al<3+> under alkaline conditions. The method comprises the steps: (1) adding 24.4ml of
ammonia water (NH4(OH)) and
methanol into 73.20ml of water, uniformly mixing the
ammonia water, the
methanol and the water, then, adding 32.78g of DTPA into the mixture, and thoroughly dissolving DTPA; (2) fetching another
beaker, adding 593.34ml of water and 197.78ml of
ammonia water into the
beaker, uniformly mixing the water and the ammonia water thoroughly; and (3) simultaneously adding solutions obtained in the step (1) and the step (2) into a solution containing MgCl2.6H2O and AlCl3.6H2O so as to prepare the DTPA modified material, carrying out
spray drying, then, sieving the dried DTPA modified material by a
sieve with the pore size of 200 meshes (75 microns) so as to form a heavy-
metal adsorption material for a DGT coupled film, then, adding the heavy-
metal adsorption material into a
polyacrylamide gel solution, and carrying out reaction at a certain temperature, thereby preparing the DGT coupled film. The gel film prepared by the method disclosed by the invention has the effects of heavy-
metal adsorption and short-time full dissociation, and the
disadvantage that the dissociation of the former heavy-metal
coupling phase is slow and incomplete is overcome. The materials used are cheap and are easily prepared, and no secondary
pollution is caused, so that the popularization and application of a DGT technology are facilitated.