Study of the Catalytic Effects of Trace Titanium on Oxidation of Pyronin B with Hydrogen Peroxide and its Application

Abstract

A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts titanium (IV), based on the catalytic effect of Ti (IV) on the oxidation pyronin B with hydrogen peroxide in 0.02 mol/L sulfuric acid, is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of pyronin B at 555 nm. The detection limit of the method is 0.017 μg/L, and the linear range is 0.055–1.0 µg/L. The influences of reaction medium and acidity, concentrations of reactants, reactive temperature and foreign ions is also discussed. The optimum reaction conditions were established. The relative standard deviation for 11 replicate measurements of 0.010 and 0.020 μg/25mL of titanium (IV) were 2.8 % and 2.3 %, respectively. In combination with solvent extraction separation, the method has been successfully applied to the determination of trace titanium (IV) in rock samples. The results are in good agreement with the certified volumes with the relative standard deviations (RSD) of 1.6 %–3.6 %.