Silica gel modified with some sulfonated chelating reagents as a sorbent for the preconcentration, isolation and separation of metal ions

A new method of preparation of chelating sorbents is discussed: silica gel is impregnated with water-insoluble ion pairs composed of a cation of quaternary ammonium salt (e.g., Aliquat 336) and an anion of some sulfonated chelating reagent. The usefulness of these sorbents in the trace analysis of metal ions is demonstrated - for preconcentration of trace amounts of these ions, for their separation from macroamounts of other metal ions and for the separation of their mixtures by column extraction chromatography. The ion pair with the complexed metal can be eluted from the column with a polar organic solvent. The present review article is a summing-up of investigations carried out in out research group.