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.

Methods of analysis of reusable metal-containing material (RMR) are considered in the review: X-ray fluorescence, atomic absorption spectrophotometry, and atomic emission and mass spectrometry with in

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%.

For the first time, inductively coupled plasma mass spectrometry (ICP-MS) was developed for determining the target elemental composition of gadolinium–aluminum garnets with the varying composition Gd_3–xCe_xSc_yAl_5–yO₁₂, where x = 0.01–0.16 and y = 0.25–1.75. This fact has a fundamental importance for obtaining optical ceramics with predictable properties. Using the proposed acid mixture and temperature-time program, microwave digestion of these materials and complete transfer of the sample’s components into solution were possible. Moreover, we estimated the influence of the matrix composition, sample introduction system and collision cell on the limits of determination (LOD) of impurity elements by ICP-MS (Mg, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, La, Pr, Nd, Sm, Eu, Tb, Er, Ho, Tm, Yb, and Lu). It has been shown that the conditions of mass spectral analysis proposed in this work provide LOD of target analytes in the range of 1∙10⁻⁶–4.15∙10⁻³ wt.%. The accuracy of the obtained results has been confirmed by the added-found method and by analyzing samples with known chemical composition. The standard deviation of repeatability (S_r) of the developed technique lies in the range from 1 to 6%. The developed analysis method is characterized by sensitivity, robustness and multi-elementality. It has application potential for other optical and ceramic materials of similar composition.

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.

Hydroxyapatites (HA) and tricalcium phosphates (TCP) (analogs of the mineral component of bone tissue in phase and dynamic composition) serve as the basis for the creation of ceramic, cement, and composite biomaterials. Since the crystallographic structures of HA and TCP are prone to isomorphous substitution, their modification with ions of various metals including rare earth elements (REEs) to obtain materials with the properties required for medical use is a relevant field of research. To obtain the specified properties, it is necessary to control not only the structure, but also the chemical elemental composition of the material. The analytical capabilities of the continuum source electrothermal atomic absorption spectrometry (CS-ETAAS) are studied in relation to the determination of europium and ytterbium in hydroxyapatites and tricalcium phosphates including the choice of conditions and modes of analysis (temperature–time program, use of modifiers, plotting of a calibration dependence, etc.) to obtain accurate results. It is found that the use of magnesium nitrite and EDTA as matrix modifiers makes it possible to increase the absorption of analytes by almost 1.5 times and by 10–30%, respectively. The possibility of simultaneous determination of Eu and Yb in the range of contents from 0.09 to 2 wt % with a relative standard deviation of no more than 6 rel % is demonstrated. The trueness of the determination of europium and ytterbium in HA and TCP samples doped with each or both REEs is confirmed by varying the sample weight and comparing with the results of the ICP-AES reference method.