Determination of nonferrous and rare earth metals impurities in scandium oxide by inductively coupled plasma mass spectrometry

The purpose of this study is the development of the method of the impurities’ determination in scandium oxide by inductively coupled plasma mass spectrometry (ICP-MS). The methodology of the work included: the analysis of the normative documentation regulating the nomenclature, the content of the impurities in scandium oxide and the methods of their determination; carrying out a preliminary semi-quantitative analysis of Sc2O3 by ICP-MS and selection of the elements as impurities for further study; selection of the elements’ isotopes and the conditions for ICP-MS analysis; study of the effect of the matrix element (scandium) on the results of the direct determination of impurities; the assessment of the accuracy and reproducibility of the determination. 31 elements were selected as impurities: Na, K, alkaline earth metals, Al, 3d-elements, Pb, 15 rare earth elements and thorium. The effect of the matrix elemental scandium on the direct determination of the impurities was investigated. Considering spectral and non-spectral effects on the determination of impurities in scandium oxide was carried out by the standard addition and the internal standard methods. Indium solution was used as the internal standard. Metrological characteristics of the developed technique: reproducibility limits, accuracy limits and expanded uncertainty were calculated.