The GB/T 23594.2-2009 standard defines a method for the determination of fifteen rare earth element oxides in samarium europium gadolinium enrichment. The method is determined by dissolving the sample in muriatic acid and using an argon plasma Light source in a dilute acid medium. The determination results need to be naturalized to ensure accuracy. The standard details the required reagents and materials, including different concentrations of muriatic acid, nitric acid, hydrogen peroxide, and the preparation of standard storage solutions for oxidation of lanthanum and cerium. These solutions are used for standardization and calibrating to achieve accurate determination of rare earth element oxides.