Fluorimetric determination of cerium(IV) with ascorbic acid.

A simple, sensitive, and selective method for the determination of cerium(IV), based on the oxidative reaction between cerium(IV) and ascorbic acid, has been described. The fluorescence comes from Ce(III) at lambda(excitation) 298 nm and lambda(emission) 358 nm, which, in turn, is obtained from the oxidation of ascorbic acid by Ce(IV) in the presence of sulfuric acid. The optimum conditions such as concentrations of ascorbic acid, sulfuric acid media and pH of the buffer solution were investigated. The fluorescent intensity of the system is linear over the range 0.0531 microg/ml to 0.3322 mg/ml Ce(IV) and detection limit and correlation coefficient are 0.0145 microg/ml and R=0.99987, respectively.