Spectrophotometric determination of niobium(V) as a mixed ligand complex of protocatechuic acid and 1,2-diaminocyclohexanetetraacetic acid

Niobium(V) has been determined spectrophotometrically as a mixed ligand complex with protocatechuic acid and trans-1, 2-diaminocyclohexanetetraacetic acid(DCTA). Measurements are carried out at 460 nm at pH 3.0, in tartrate medium, 30 min after the preparation of the solution at room temperature. The system obeys Beer's law over the range 0.37-9.66 μg of Nb/ml. The sensitivity of the method is 0.013 μg/ml of Nb. Interference due to many ions has been studied. Niobium has been also determined successfully in a few synthetic cationic mixtures. (author)