钛（IV）催化考马斯亮蓝G褪色光度法测定痕量钛

A new kinetic spectrophotometric method for the determination of trace titanium(Ⅳ) has been developed, based on the catalytic effect of trace amount titanium(Ⅳ) on the discoloring reaction of coomassie brilliant blue G with potassium bromate in dilute HCl solution and in the presence of 2,2'-bipyridine as an activator. The decrease in the absorbance has a quantitative relationship with the concentration of Ti(Ⅳ). The factors including reaction medium, concentrations of reagent, reaction temperature and time, influence of coexisting ions on the reaction are discussed, and the optimal reaction conditions are established. The kinetic parameters of reaction order and apparent activation energy are also determined. The detection limit is 0.021g/L and the linear range of determination is 0.06-1.0μg/L. The method has been applied to the determination of titanium(Ⅳ) in rock samples, and the results are in agreement with the certified values.