The production of Certified Reference Materials (CRMs) is one of the essential activities of the National Institute of Metrology, Quality and Technology (Inmetro) to ensure metrological traceability of inorganic elemental measurements in Brazil. This work presents a set of procedures for purity assessment and in-house certification of high-purity salts, implemented at the Laboratory of Inorganic Analysis, from the Chemical and Thermal Metrology Division at Inmetro. We developed and validated methodologies based on inductively coupled plasma mass spectrometry, energy-dispersive X-ray fluorescence spectrometry and inductively coupled plasma optical emission spectrometry measurements with standard addition calibration in order to determine the mass fraction of up to 71 elements considered as possible impurities. The purity of inorganic salts was determined using the mass balance approach with expanded measurement uncertainties smaller than a mass fraction of 0.007 %. All procedures were performed according to the ISO 17034:2016 standard. The CRMs will be used for the production and certification of single-element calibration solutions at Inmetro.

中文翻译：

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使用质量平衡方法对 Inmetro 的无机内部认证参考材料生产进行纯度评估

认证标准物质 (CRM) 的生产是国家计量、质量和技术研究所 (Inmetro) 的重要活动之一，以确保巴西无机元素测量的计量可追溯性。这项工作介绍了一套用于高纯度盐的纯度评估和内部认证的程序，这些程序在 Inmetro 化学和热计量部门的无机分析实验室实施。我们开发并验证了基于电感耦合等离子体质谱、能量色散 X 射线荧光光谱和电感耦合等离子体发射光谱测量以及标准添加校准的方法，以确定多达 71 种被视为可能杂质的元素的质量分数。无机盐的纯度是使用质量平衡方法确定的，扩展的测量不确定度小于 0.007% 的质量分数。所有程序均根据 ISO 17034:2016 标准执行。CRM 将用于 Inmetro 单元素校准解决方案的生产和认证。