Report of the CCQM-K152. Assay of potassium iodate

• Published in: Metrologia Vol. 58; no. 1A; p. 8005
• Main Authors: Sobina, Alena, Shimolin, Alexandr, Sobina, Egor, Tabatchikova, Tatyana, Ortiz-Aparicio, José Luis, Lara-Manzano, Judith Velina, Borges, Paulo Paschoal, Neves, Rodrigo de Santis, Sobral, Sidney Pereira, Sena, Rodrigo Caciano de, Osorio, Ana Catalina Palacios, Almeida, Marcelo Dominguez de, Iglesias, Ana, Lozano, Hernán, Liandi, Ma, Bing, Wu, Naijie, Shi, Tao, Zhou, Jianying, Zhang, Asakai, Toshiaki, Mariassy, Michal, Uysal, Emrah, Liv, Lokman, Tunc, Murat, Coskun, F Gonca
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2021
• Subjects: Assaying; Coulometers; Coulometry; Electrochemical analysis; Impurities; Iodine; Measurement methods; Metrology; Oxidizing agents; Potassium; Purity
• ISSN: 0026-1394; 1681-7575
• DOI: 10.1088/0026-1394/58/1A/08005

Main text The CCQM-K152 key comparison in parallel with CCQM-P192 pilot comparison were organised jointly by the Inorganic Analysis (IAWG) and Electrochemical Analysis and Classical Chemical methods (EAWG) working groups of CCQM to test the abilities of the metrology institutes to measure the amount content of the non-metallic elements in high purity salts as well as assaying high purity salts to be used as primary standards. Eight NMIs participated in the key comparison CCQM-K152. Ural Research Institute for Metrology (UNIIM) (since 2020 it has been called Affiliated Branch of D.I.Mendeleev Institute for Metrology (VNIIM-UNIIM)), Russian Federation, acted as the coordinating laboratory of the comparison. There were two measurands: the amount content of oxidants expressed as potassium iodate, mol/kg, and the mass fraction of iodine, kg/kg. The measurement methods used by participants for the amount content of oxidants expressed as potassium iodate were constant current coulometry and titrimetry. For the mass fraction of iodine results were provided by 5 NMIs, 3 of them used the direct approach (recalculation from coulometric or titrimetric results) and 2 NMIs implemented the indirect approach based on impurities assessment using combination of the instrumental methods (ion chromatography, ICP OES, ICP MS). In general, good overlap of results was observed for both measurands. Direct and indirect approaches for purity determination of pure salt provide overlapping results when impurities are summarized in ionic form. The suitability of coulometry for assay of high purity materials was demonstrated again, and some possible technical problems were highlighted. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).