Determination of rare earths in monazite sand and rare-earth impurities in high-purity rare-earth oxides by high-performance liquid chromatography

Abstract

Using high-performance liquid chromatography it has been possible to separate 14 lanthanide elements in less than 40 min by elution with an α-hydroxyisobutyric acid concentration gradient. LiChrosorb KAT cation exchanger (10 µm) is used as the packing material and the eluted lanthanides are detected with an ultraviolet detector after complexation with Arsenazo III. The detection limit is about 0.1 µg. Determinations of the rare-earth composition in monazite sand and rare-earth impurities in high-purity lanthanum(III), cerium(IV), samarium(III) and yttrium(III) oxides were carried out. The proposed method is more convenient than others, and the separation of major components is not necessary in analyses of high-purity rare earths; the elution time is only about 1 h.