SIMULTANEOUS DETERMINATION OF DYSPROSIUM, HOLMIUM AND ERBIUM IN HIGH-PURITY RARE-EARTH-OXIDES BY2ND-ORDER DERIVATIVE SPECTROPHOTOMETRY

High purity individual rare earth oxides are increasingly used as majo r components in lasers (Y2O3), phosphors (YVO3, Eu2O3), magnetic bubbl e memory films (Gd2O3) and refractive-index lenses and fibre optics (L a2O3). The determination of individual lanthanides in high purity rare earth oxides is a more important and difficult task. This paper repor ts the utilization of higher order derivative spectrophotometry for th e simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides. The developed procedure is simple, reliable and allows the determination of 0.001 to 0.2% of dysprosium, holmium and erbium in several rare earth oxides.