Development of REE-doped CaWO single crystals as reference materials for microanalysis of scheelite LA-ICP-MS

• Published in: Journal of analytical atomic spectrometry 2020-05, Vol.35 (5), p.886-895
• Main Authors: Ke, Yuqiu, Zhou, Jianzong, Yi, Xiaoqing, Sun, Yijian, Shao, Jianfeng, You, Shiyong, Wang, Wei, Tang, Yunzhi, Tu, Chaoyang
• Format: Article
• ISSN: 0267-9477; 1364-5544
• DOI: 10.1039/d0ja00015a

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been widely used for in situ microanalysis of elemental concentrations in solid samples, but its application is hampered by a lack of matrix-matched and homogeneous reference materials (RMs). In this work, a new method for preparing matrix-matched and homogeneous LA-ICP-MS reference materials has been developed. A multiple rare earth element (REE) doped CaWO 4 single crystal (CaW-1) was successfully prepared by the Czochralski technique. The matrix composition and crystal structure were confirmed by X-ray diffraction (XRD) and electron microprobe analysis (EMPA), which indicates that these crystals have a matrix composition of CaWO 4 and are matrix-matched with natural scheelite. The homogeneity of REE distribution was systematically studied by seven methods and the results demonstrated that REEs are distributed homogeneously in the CaWO 4 single crystal with slight fluctuation (RSDs: ca. 4%). It can be concluded that the synthesized CaWO 4 single crystal meets both crucial requirements, matrix-matched and homogeneous distribution, for an LA-ICP-MS reference material, and therefore it was used to quantitatively calibrate REE concentrations in natural scheelite. The results showed that acceptable analytical errors (