Determination of trivalent terbium ion in mineral by flow injection chemiluminescence

A simple flow injection chemiluminescence(CL) analysis method for the determination of terbium in mineral sample is reported. It is based on luminescence produced by NaIO4-H2O2 CL system sensitized by [Tb(EDTA)(2)](-). The relative chemiluminescence intensity of the Tb3+-EDTA-NaIO4-H2O2 system is proportional to the amount of Tb3+. The maximum CL intensity was obtained at concentration of 2.0 x 10(-3) mol/L EDTA, 0.048% H2O2 and 1.0 X 10(-2) mol/L NaIO4. The linear range and detection limit for Tb3+ are 1.0 x 10(-7) similar to 1.0 x 10(-5) mol/L and 8.0 x 10(-9) mol/L, respectively. The relative standard deviation for 12 independent determinations of 1.0 x 10(-6) mol/L Tb3+ was 3.2%. This method was successfully applied to the determination of terbium in rare earth oxide and mine. And the mechanism of chemiluminescence was proposed.