Analysis of some metal ions using silica gel modified with Acid Orange 7 as a sorbent

Silica gel impregnated with a mixture of Aliquat 336 and Acid Orange 7 (Ora nge II) was used as a chelating sorbent for 14 metal ions: Na, K, Mg, Ca, A l, Zn, Cu, Cd, Fe(III), Mn, Pb, Cr(III), Co and Ni. The relative capacities of the sorbent toward the metal ions in the pH rang e 1-9, as well as the concentrations of HCl and HClO4 required for elution of the retained metals were determined. All the retained metals could be el uted with dilute solutions of HClO4 without elution of the chelating agent from the sorbent. The sorbent was used for preconcentration of trace amounts of some metals f rom aqueous solutions before their determination by AAS, for the separation of metal ion mixtures by column - extraction chromatography and for additi onal purification of some salt solutions from trace amounts of Zn, Cd, Pb a nd Cu. The effectiveness of purification was confirmed by anodic stripping voltammetry.