DETERMINATION OF METAL-IONS COMPLEXED WITH 2,6-DIACETYLPYRIDINE BIS(N-METHYLENEPYRIDINIOHYDRAZONE) BY CAPILLARY ELECTROPHORESIS

Metal ions were determined quantitatively and selectively by complexat ion with 2,6-diacetylpyridine bis(N-methylenepyridiniohydrazone) (H(2) dapmp) and separation of the metal ion complexes formed using capillar y zone electrophoresis. The effect of various alkyltrimethylammonium i ons added to the running electrolyte on the migration behaviour of cat ionic chelate complexes was examined. As a result, some evidence was o btained that both electrophoretic migration and micellar partitioning play the major role in the separation mechanism. Optimum resolution of metal-H(2)dapmp complexes was achieved with a 10 mM sodium berate buf fer (pH 9.0) containing 75 mM tetradecyltrimethylammonium bromide and 10 mM sodium n-octanesulfonate as an ion-pairing counterion. With this micellar buffer system, it was possible to separate and determine up to fourteen metal ions in a single run within 12 min using fused-silic a capillaries at 15 kV and direct on-column UV detection at 254 nm. Li near calibration ranges of more than two orders of magnitude and detec tion limits at mid-ppb levels are presented for the metal complexes of Cd(II), Co(II), Cu(II), Fe(III), Hg(II), Mo(VI), Sc(III), U(VI), V(V) , Y(III) and Zn(II).