Rare-earth metals and compounds on their basis are in demand for the development and production of functional materials, such as optical ceramics, permanent magnets, phosphors, catalysts, glasses, alloys, etc. Unique physical and chemical properties of these materials largely depend on their elemental composition (panoramic and target), which must be controlled at all stages of production, from the initial compounds to intermediate and final products. Mass spectrometry with various ionization sources (inductively coupled plasma, vacuum spark discharge, glow discharge, laser source, secondary ion source) and sample introduction systems (solutions’ spraying, laser sampling, electrothermal evaporation) is one of the most promising and in-demand methods for determining target elements with high sensitivity in materials of complex composition. There are a number of other advantages offered by this method, namely the selectivity of the signal from the elements being determined, a possibility of conducting multi-element analyses, and the accuracy of the analysis results. However, materials of complex composition, including those containing rare-earth metals as main elements, require studying the influence of analysis conditions and other factors in order to obtain reliable results and to develop analytical procedures. The article provides a review of publications containing methodological solutions and approaches to overcome the limitations of mass spectrometry with various ionization sources in relation to the analysis of rare-earth metals and functional materials based on them. The review includes Russian and foreign publications from 2014 to 2023.

This work describes a two-stage technique of X-ray fluorescence (XRF) analysis of rare earth niobates. A comparison between the two approaches revealed that the Fundamental Parameters Method (FPM) can be employed for a rapid preliminary assessment of the composition of the resulting material and the construction of calibration curves can be used to determine the contents of the major elements with precision. The results of the relative standard deviation (RSD) for FPM were no more than 7%, while the approach to construct calibration curves had an RSD of no more than 1%. Calibration samples were prepared using the same synthesis method as the study samples to construct the calibration curves. The possibility of constructing calibration dependencies using mixtures of oxides was assessed, but this approach could not provide the desired accuracy. The obtained results have been shown to have a good correlation with inductively coupled plasma optical emission spectrometry. The developed technique enables the determination of the major components in niobates containing two and three rare earth elements, which are used as optical materials and medium-entropy ceramics.

An analytical procedure for inductively coupled plasma atomic emission (ICP-AES) analysis of iron garnets of the composition Y 3 – x Ce x Fe 5 – y Ga y O 12 , where x = 0.4 – 0.5 and y = 2.4 – 2.6 with preliminary microwave decomposition of the sample is described. The compositions of acid mixtures (HCl/HNO 3 ), as well as modes of microwave heating (holding time and temperature), providing complete dissolution of the samples are proposed. In addition to optimized sample preparation, conditions for ICP-AES analysis of cerium-doped yttrium iron garnets were studied. The effect of matrix components (Y, Ce, Fe, Ga) on the determination of doping elements was revealed and studied. The operating parameters of the spectrometer (ICP power and nebulizer flow rate) have been substantiated, which make it possible to reduce the matrix effect of Fe, Ga, Y, Ce on the elements Na, Mg, Al, Si, P, K, Ca, Sc, Cr, Mn, Co, Ni, Cu, Zn, Se, Cd, Sn, Te, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb in iron yttrium garnets by the ICP-AES. ICP-AES measurements were performed in the axial and radial mode for trace elements and in the radial mode for matrix elements. The limits of quantification (LOQs) of most elements ranged within n × 10 –5 – n × 10 –4 wt.%. The accuracy is confirmed by the spike recovery test. The relative standard deviation is in the range of 1 – 5% depending on the selected plasma view mode and the analyzed analytes. The developed method makes it possible to determine macro- and microcomponents in yttrium iron garnets in a wide range of concentrations with a high accuracy.

Determination of the chemical composition of waste Sm-Co magnets is required for their efficient recycling. The non-stereotypical composition of said magnets makes an analysis extremely challenging. X-ray fluorescence spectrometry is a promising analytical tool for this task. It offers high accuracy and simplicity of sample preparation as it does not require sample dissolution. However, a serious limitation of X-ray fluorescence analysis is the spectral interference of matrix elements and impurities. In this work, a two-stage technique has been developed for the determination of the main components (Sm, Co) and impurities (Fe, Cu, Zr, Hf, Ti, Ni, Mn, Cr) in samples of spent samarium–cobalt magnets using wavelength dispersive X-ray fluorescence spectrometry. In order to overcome the main limitation of the chosen method and to maximize its capabilities of qualitative and quantitative analysis, we propose an approach to the selection of analytical lines and experimental conditions, as well as a preparation method for the calibration standards. The obtained results have been shown to have a good correlation with ICP-OES. The limits of detection are in the range of 0.001–0.02 wt%, and the limits of quantification are 0.003–0.08 wt%.

A possibility of using S,N-containing sorbents for the analysis of materials based on rare earth element compounds with the determination of impurities in the sorption concentrate by arc atomic emission spectrometry is studied. The properties of S,N-containing sorbents in aqueous solutions and various rare earth matrices are studied. A methodological approach to the sorption preconcentration of impurities in REE-based materials followed by a direct analysis of the sorption concentrate by arc atomic emission spectrometry is described. The results of the development of a spectrochemical method for determining impurities in rare earth element materials are presented, and performance characteristics are evaluated.

Present article provides a method of Bi@SiO 2 core@shell nanocomposites obtaining via surface modification of laser-synthesized bismuth nanoparticles with tetraethoxysilane.The SiO 2 shell coating on Bi nanoparticles was demonstrated to form spherical nanoformulations with the mode of size distribution at 250–300 nm. The developed approach is a novel perspective alternative to the traditional methods that allows designing biocompatible Bi-based nanocomposites for the sensitization of multimodal theranostics.

In a new series of Ln III –Cr III cyclopropane-1,1-dicarboxylates, a decrease in the Ln 3+ ionic radius leads to a change in a space group and the transition of a 3D framework structure (Ln = Eu, Gd, Tb) into a 2D layered one (Ln = Dy, Ho, Y, Er, Yb).

The effectiveness of using materials based on rare earth elements (REE) largely depends on their impurity composition, which affects their structure and properties. Before the analytical quality control of REE-based materials and initial substances for their production, it is necessary to determine both macrocomponents and impurity elements with high sensitivity and accuracy. A complex of atomic emission and mass spectral analytical methods is often used for the determination of impurities in REE-based materials in the range from 10–5 to 5.0 wt.%. However, the analysis of such materials, even using these modern high-sensitivity methods is a difficult task due to spectral and matrix interferences. Therefore, different preliminary separation/concentration procedures are needed to determine both rare earth and other impurities. This article reviews publications is devoted to preconcentration methods for spectral and mass spectral analysis of REEbased materials and, in part, a number of other analytical techniques. It was shown that the most common approaches are liquid extraction and chromatography. Sorption, cloud-point extraction and coprecipitation are also used. There is no universal method. Each of the methods discussed in this article has its own advantages and limitations. The analytical completion of the method confirms the effectiveness of the selected separation/concentration method in each specific case.

The boundaries of Mg1 – xNixGa2O4 solid solutions (0 ≤ х ≤ 0.5) with a spinel structure synthesized by the gel combustion method, annealed at 1000°C, and furnace cooled have been experimentally determined for the first time. Mg1 – xNixGa2O4 samples (0 ≤ х ≤ 1, step х = 0.1) with an inverse spinel structure have been studied by X-ray diffraction and IR spectroscopy. It has been found that the range of the (Mg,Ni)Ga2O4 solid solution can deviate from the line connecting the stoichiometric compositions MgGa2O4 and NiGa2O4. The diffuse reflectance spectra of Mg0.9Ni0.1Ga2O4 and Mg0.5Ni0.5Ga2O4 spinels show an intense absorption band corresponding to Ni2+ in the near-IR range, which is of great interest for using this property in laser and optoelectronic technologies with minimal negative impact on the environment.

Samples of the initial composition Mg1 – xNixGa2O4 (0 ≤ х ≤ 1, step х = 0.1) synthesized by the gel combustion method and annealed at 1000°C have been studied by X-ray powder diffraction and IR spectroscopy. For homogeneous samples of (Mg,Ni)Ga2O4 with a spinel structure, the gallium nonstoichiometry has been determined by inductively coupled plasma atomic emission spectrometry. Within the framework of the MgO–NiO–Ga2O3 system, the boundary of the homogeneity region of spinel (Mg,Ni)Ga2O4, which is in equilibrium with halite (Mg,Ni)O, has been outlined. An analysis of the diffuse reflectance spectra of (Mg,Ni)Ga2O4 in the range of 350–900 nm revealed intense absorption bands from Ni2+ in octahedral positions and showed an increase in their intensity with an increase in the nickel content in the spinel.

The efficiency of using rare earth metals largely depends on their impurity composition, which affects the structure and properties of materials. Before the analytical control of materials based on rare earth elements (REEs) and the starting materials for their production, the task is to determine both macrocomponents with high accuracy and impurities with high sensitivity, correctness, and precision. To determine the impurities in REE-based materials in the range from 10–5 to 5.0 wt

Исследование и разработка материалов на основе редкоземельных металлов востребованы и перспективны для микроэлектроники, оптической связи, лазерных технологий и др. Важным требованием для их эффективного применения являются химическая чистота и прогнозируемый состав исходных веществ. Установление чистоты исходных РЗМ и их соединений, контроль состава промежуточных и конечных продуктов представляют собой сложную аналитическую задачу. Cозданы комплексные методики анализа магнитных, люминофорных и оптических материалов и исходных веществ для их получения методами атомно-­эмиссионной спектрометрии с индуктивно связанной плазмой, масс-спектрометрии с индуктивно связанной плазмой и дугового атомно-­эмиссионного анализа . Комплексное взаимодополняющее применение этих методов обеспечивает высокую точность и достоверность результатов, расширяет границы определяемых содержаний целевых примесей, перечень аналитов и номенклатуру анализируемых материалов.

In this article, inductively coupled plasma mass-spectrometry (ICP-MS) and inductively coupled plasma optical-emission spectrometry (ICP-OES) were used for the development of an analytical procedure for analysis of the waste of Sm-Co magnets. Experimental parameters related to microwave digestion processes and acid concentrations were optimized. Microwave digestion was carried out in mixtures of HF, HCl, HNO3 and H2SO4. The complete dissolution of the samples occurred in the system: 10 mL H2O, 2 mL HNO3, 10 mL HCl and 1 mL H2SO4. The dependence of the matrix effect on the ICP-MS analysis of waste Sm-Co magnets was studied and optimal instrumental parameters were investigated (nebulizer gas flow, sampling depth and potential at the extractor lens). The optimal conditions were a nebulizer gas flow of 0.85–0.90 L/min, a sampling depth of 101, potential at the extractor lens of −400 V and a sample flow rate of 50 rpm. A recovery test and inter-method experiments were performed to verify the accuracy of the proposed method.

An analytical procedure for direct determination of Al, Mg, Ti, Cr, Mn, Nb, La, Nd, Eu, Gd, Tb, Dy, Tm, Yb, Lu, Hf, Ni, Cu, Fe, Zr Sm and Co by ICP-OES in waste samarium-cobalt magnets has been developed. The significant influence of the matrix on all determinable components has been shown. The influence of operation parameters (ICP power and nebuliser flow rate) on the matrix effect has been studied using two plasma observation modes (axial and radial). For the first time, the optimal conditions for ICP-OES analysis of waste samarium-cobalt magnets has been substantiated (ICP power 1400 W, nebuliser flow rate 0.5–0.6 L/min). The analytical capabilities of the method have been evaluated using spike recovery test, certified reference materials and comparison with ICP-MS. ICP-OES measurements were performed in the axial mode for trace elements (with concentrations of n·10−4-n·10−2 % wt.) and in the radial mode for matrix elements and analytes (with concentrations higher than n·10−2 % wt.). The limits of quantification (LOQs) were in the range of n·10−5 wt% for Mn, Zr and Yb and n·10−4 wt% for Al, Mg, Ti, Cr, Hf, La, Ni, Cu, Tb, Lu, Nb, Fe, Nd, Eu, Gd, Dy and Tm. RSD ranged from 0.2 to 10.6%.

Procedures are developed for the multielement analysis of high-purity cerium oxide for the manufacture of phosphors and optical materials using inductively coupled plasma–mass spectrometry (ICP–MS) and inductively coupled plasma–optical emission spectrometry (ICP–OES). The “robust” settings of the mass spectrometer are given suitable to determine Fe, Ni, Cr, Co, Cu, V, Mn, and rare-earth metals in cerium oxide (nebulizer gas flow, liquid flow, plasma sampling depth, the extract lens voltage), lowering the matrix effect and, therefore, enabling the use of more concentrated solutions for analysis. The effect of the matrix element in the direct analysis of cerium oxide by ICP–OES is estimated. The combination of mass spectral and atomic emission methods has some advantages, expands the range of elements to be determined, and increases the reliability of the analysis. In particular, the use of ICP–OES makes it possible to determine low concentrations of terbium in cerium oxide (the limit of determination for terbium by ICP–OES is 1 × 10–4 wt %) and decreases the limits of determination for Fe and Pr by a factor of 4–5 compared to ICP–MS. The limits of determination of the target components (Fe, Ni, Cr, Co, Cu, V, Mn, and rare-earth metals) in cerium oxide by ICP–MS and ICP–OES are in the range of n × 10–6– n × 10–4 wt %.

Current trends in the application of rare-earth metals (REMs) in two major scientific and technological fields—the production of magnetic and luminescent materials—are considered. It is shown that it is REMs that endow these products with unique properties. The information on the content of the matrix and doping components and their influence on achieving the required characteristics of the most popular magnetic materials is systematized. The potential of new combinations of REMs for further progress in the production of magnetic materials for various purposes is described. Along with the traditional cobalt–samarium and neodymium–iron–boron compositions, new magnetic materials with increased hysteresis properties and better time–temperature stability are developed, and phases with variable valence, used as memory elements in information systems, are synthesized. In addition, the article also reviews and summarizes the results of studies in the creation of luminescent materials, which is another important area of application of REMs. Phosphors based on compounds of REMs are used in the production of high-pressure mercury lamps with improved characteristics, X-ray screens, high- and low-pressure fluorescent lamps, and screens for electrooptical converters. Narrow-band phosphors based on REM compounds are of interest for lamps used for growing plants, especially in areas with a cold climate, where growing plants year-round is possible only with the use of additional radiation sources. The trends in the synthesis of luminescent materials with varied REMs and their combinations are revealed. Emphasis is placed on the need to use chemically pure REM precursors in the synthesis of such materials. The prospects for the creation of nanophosphors, as well as the improvement of methods of synthesis and diagnostic techniques, are noted.

It is difficult to name such an area of modern science and technology where rare earth metals (REM) would not be used. Generalization of all existing information on this issue due to its enormous volume and variety is hardly possible and advisable. Therefore, to write literary reviews in this area, one or two relevant segments in a global issue are usually selected and considered in detail. In this review, metallurgy and the production of optical materials are selected as such segments. In metallurgy, first of all, it should be noted the use of rare earth metals in the composition of multicomponent heat-resistant alloys for aviation and space technology, as deoxidizers, for the formation of a perfect structure when creating composite materials and coatings. The use of REM is growing both in ferrous and nonferrous metallurgy. In ferrous metallurgy, increasing the resistance of austenitic steel to oxidation by adding yttrium and cerium, creating composite coatings with additives of yttrium oxide to achieve special properties, etc. In nonferrous metallurgy, composites based on aluminum alloys with additives of cerium oxide; composites based on tin bronze doped with cerium oxides; titanium alloys doped with yttrium, etc. Rare earth metals are an integral part of research on the creation of lasers, solar cells, optoelectronic amplifiers, etc. for use in optoelectronics and other fields of glass materials and ceramics production. These areas of application of rare-earth metals include aluminosilicate glasses, borate glasses, and various types of optical ceramics. A group of new alloyed materials for various laser devices and installations has been created. Such materials include fluortellurite glasses doped with erbium, multicomponent fluoride glasses doped with europium and holmium, tungsten sodium phosphate glasses doped with trivalent REM ions, germanate glass doped with erbium and ytterbium, and others. Research in this area is continuously expanding. The study was supported by a grant from the Russian Science Foundation (project No. 20-13-00180).