Rare earth metals are of strategic importance for all developed countries of the world community. Modern opto- and radio electronics, instrumentation and automotive, chemical industry, metallurgy, nuclear and alternative energy are not complete without them. The applications and price of rare earth materials directly depend on their purity. In this regard, the control of chemical composition is an integral part of their production and consumption. Currently, it is relevant in the analytical control of rare earth materials to expand the range of determined impurity elements and increase the sensitivity of the analysis.