Separation of uranium(VI) and transition metal ions with 4-(2-thiazolylazo)resorcinol by capillary electrophoresis

A capillary electrophoresis method utilizing 4-(2-thiazolylazo)resorcinol ( TAR) was developed to separate uranium, cobalt, cadmium, nickel, titanium a nd copper metal ions. TAR was chosen as the visible absorbing chelating lig and because of its ability to form stable complexes with a wide variety of metals. Several parameters that included pH, electrophoretic run buffer con centration, buffer type and the influence of chelating Ligand in the electr ophoretic ran buffer were examined to determine the best separating conditi ons. Optimum separation of the six metal chelates was achieved in a 15 mM N a2B4O7-NaH2PO4, pH 8.3 buffer containing 0.1 mM TAR. Method validation incl uded injection and method precision studies as well as detection limit and linear dynamic range determination. High-ppb to low-ppm (w/w ratio) detecti on limits were achieved with linear dynamic ranges between 0.1 and 75 ppm. (C) 2001 Published by Elsevier Science B.V.