Separation of vanadium, niobium and tantalum as ternary mixed-ligand complexes by capillary electrophoresis using chelation with 4-(2-pyridylazo) resorcinol and tartaric acid

Vanadium(V), niobium(V) and tantalum(V) were separated as ternary mixed-lig and complexes by capillary electrophoresis using 4-(2-pyridylazo)resorcinol (PAR) as the color chelating reagent. Four carboxylic acids such as tartar ic acid (Tart), oxalic acid, citric acid and acetic acid were investigated as the additional ligand. The first was chosen as the best. Other parameter s such as the concentration ratio of Tart to PAR, buffer concentration, inj ection time and applied voltage were also optimized. Under the optimized co nditions, a complete separation of the three metal complexes was accomplish ed within 10 min. A linear calibration curve in the range of two orders of magnitude was obtained.