Preparation of Sol-Gel Bound Diethylenetriamine

The following procedure affords a material useful for illustrating the principle of solid phase extractions. One prepares the gel by a copolymerization:

Once the polymer is formed, it is a colorless powder. When mixed with a Cu(II) solution, the gel turns a progressively deeper blue as the ion is extracted. When removed from the solution and placed in water the color is not released until the pH is lowered.

Polymerization:

The following proportion of reagents is mixed into a vial in the following formulation:

54ml tetramethoxysilane

6 ml N[(3-trimethoxysilyl)propyl]diethylenetriamine

60 ml methanol

60 ml 0.2M KCl

60 ml 0.1M HCl

The vial is shaken for one hour and capped with parafilm. A pinhole is opened into the parafilm and the mixture aged for two week and the gel isolated.