Metal-ion chelation chromatography on silica-immobilized 8-hydroxyquinoline

A chromatographically useful packing is prepared by immobilizing 8-hydoxyquinoline on Porasil. This material, whose capacity is about 50 μequiv/g, behaves with an efficiency of about 0.2 to 0.5 mm/theoretical plate but is capable of separating such similar metal ions as Co-Ni, Cd-Pb-Zn, and La-Gd-Yb at trace levels employing both isocratic and continuous gradient elution. On a fundamental level, the relationship between solution chelate stability and chromatographic behavior is described. 9 figures, 2 tables