SEPARATION AND DETERMINATION OF DIVALENT METAL IONS WITH UV-ABSORBING CHELATING AGENTS BY CAPILLARY ELECTROPHORESIS

Capillary electrophoresis separation of several divalent metal ions, as well as iron(III) and silver (I) was examined with chelating agents. The metal chelates separated in the capillary were measured by on-column UV-absorption detection. When 1,2-cyclohexanediamine-N,N,N' N'-tetraacetic acid(CyDTA) was used as an chelating agent in a carrier solution (pH 9) the order of the migration time (t(m)) of metal ions was as follows : Ba2+ < Sr2+ < Ca2+ < Mg2+ ( Be2+ could not be detected), Fe3+ < Mn2+ < Co2+ < Ni2+ < Cu2+ > Zn2+ and Cd2+ < Pd2+ < Ag+, Hg2+ < Pb2+ The detection limits of common metal ions were 10(-6)M, when CyDTA chelates were used. The method with CyDTA was applied to the determination of Ca2+ and Mg2+ in water samples: the separation and detection of Ca2+ and Mg2+ was carried out within 10 min, and the relative standard deviations for around 10(-4) M metal ions was less than 1.5 %.