A combined chemical x-ray fluorescence method is described for determining rare-earth elements in small amounts of complex rare-earth minerals. These elements yield a complex x-ray spectrum in which many of the analytical emission <i>L</i>α lines of a given element coincide with the <i>L</i><sub>β</sub> and/or <i>L</i><sub>γ</sub> lines of a lighter rare-earth element several atomic numbers removed. The proposed analytical scheme corrects for these interferences. Sixteen elements consisting of the lanthanides, yttrium, and scandium can be determined on as little as a 1-mg portion of the separated oxides. The oxides are dissolved in 1 ml of dilute acid, absorbed onto cellulose powder and pressed into a pellet for x-ray excitation. Chemically analyzed geologic standards are not required for calibration.
Harry J. Rose and Frank Cuttitta, "X-Ray Fluorescence Analysis of Individual Rare Earths in Complex Minerals," Appl. Spectrosc. 22, 426-430 (1968)