Reversed-phase chromatographic behavior of metal complexes with 8-hydroxyquinoline and its derivatives

Chromatographic behavior of metal complexes with 8-hydroxyquinoline, 5-chloro-8-hydroxyquinoline, and 5,7-chloro-8-hydroxyquinoline in the reversed-phase system has been studied using a variety of organic modifiers. In the acetone modifier system. the capacity factors (k') of the corresponding vanadium(V), nickel(II), and cobalt(III) complexes increased with increasing number of substituted chlorine atoms in the ligands. With acetonitrile-water as the mobile phase, the k' values of the metal 8-hydroxyquinoline complexes decreased with increasing contents of the modifier, depending on the strength of polarity parameters. The k' values, experimentally determined, can be related to the polarity parameters of organic modifiers for tervalent metal ions, but not for monovalent and divalent ions.