Capillary electrophoretic separation of several transition-metal ions as their complexes with 1,10-phenanthroline derivatives and its application to the determination of copper in duralmin alloys

Separations of five transition-metal ions (Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)) after complexation with 1,10-phenanthroline (phen), 2,2′-bipyridine and phen derivatives were investigated by capillary zone electrophoresis. The mobilities for phen and its complexes decreased in the order Co (II)>Ni(II)⇌Fe(II)>Zn(II)>Cu(II)>phen in acetate buffer at pH 6.0. The separation behavior is discussed with respect to dependence on pH, properties of the buffer, and a redox reaction between the Fe(III) and Co(II) complexes. In this method, the detection limit (S/N=3) and the linear calibration ranges of Cu(II) with phen were 30 ng ml−1 and 100–500 ng ml−1, respectively. The method with 4,7-dimethyl-1,10-phenanthroline was applied to the determination of Cu in duralmin alloys.