SEPARATION OF COBALT, NICKEL AND COPPER BY PRECOLUMN DERIVATIZATION CAPILLARY-ELECTROPHORESIS IN NONAQUEOUS MEDIUM

Separation of cobalt, nickel and copper elements as their 6-methyl-2-b enzothiazolyazo)-5-dimethylaminophenol complexes try capillary electro phoresis in nonaqueous medium was first presented. Ethanol and N, N-di methylformamide (DMF) were evaluated for the effect of nonaqueous solv ents on electroosmotic flow. The influence of the pre-column derivitiz ation conditions, some parameters such as choice and selection of orga nic solvents, concentration ratio in mixed nonaqueous medium, applied voltage on the separation were also investigated. Under the optimum co nditions(buffer: 40 mmol/L, pH 5, 0 NaAc-HAc in ethanol(50%) and DMF ( 50%) mixture, 30 kV, 575 nm as detection wavelength), the three ions w ere separated in 6 min successfully, and detection limits of 9. 18 X 1 0(-8) mol/L, 2, 79 X 10(-7) mol/L and 4. 47 X 10(-7) mol/L for cobalt, nickel and copper were achieved, respectively. The theoretical plate number reached up to 3. 2 X 10(5)/m.