Collect. Czech. Chem. Commun. 1980, 45, 819-825

Study of reaction of 5-hydroxy-6-(2-hydroxy-5-sulfophenylazo)benzo(a)-phenazine with vanadates in the presence of Septonex

Nguyen Truong Son, Milan Kotouček and Eduard Ružička

Department of Analytical and Organic Chemistry, Palacký University, 771 46 Olomouc


Reaction of 5-hydroxy-6-(2-hydroxy-5-sulfophenylazo)benzo(a)phenazine with vanadates in aqueous medium was studied in the presence and in the absence of the tenside Septonex. In acidic medium (pH 2-6), the complex VO2L is formed in both cases. The equilibrium constants for the equilibria studied were calculated and a procedure was suggested for spectrophotometric determination of vanadium.