Sensitive Kinetic Spectrophotometric method for Trace determination of Cerium (IV) Based on decolarization of Nile blue by potassium Periodate

A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of cerium (IV), based on the catalytic effect of Ce (IV) on the oxidation of Nile blue (NB) by potassium periodate is described. The reaction rate was monitored spectrophotometrically by measuring the decrease in absorbance of NB at 636 nm. The detection limit of the method was 0.15 g ml and the linear range was between 0.3–50 g ml. The effects of acidity, concentration of reactants, reaction time and temperature, and external ions were also discussed. The optimum reaction conditions were fixed and some kinetic parameters determined. The relative standard deviation for the determination of cerium (IV) at the concentration of 10 g ml was calculated to be 0.99 % (n = 11). The method has been successfully applied to the determination of trace amounts of cerium (IV) in sea, tap, and hat spring water samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 0.22–1.47%.