T. Asakai

National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
t-asakai@aist.go.jp

Al’manac of Modern Metrology № 1 (33) 2023, pages 139–149

Abstract. The analysis of oxyanions, perchlorate, chlorate, chlorite and hypochlorite ions, is of interest, especially from the viewpoint of evaluating drinking water quality. Instrumental analyses are generally performed to quantify them, and require a standard solution of corresponding ions; however, no standard solutions characterized by a metrologically valid procedure have existed. In the present study, perchlorate, chlorate and chlorite ions were characterized by performing multipath titration techniques. This technique is an approach to determine the amount of substances in chemicals by employing different stoichiometric reactions. It has decreased the risk and the contribution of unknown biases that each measurement method has, and gives further reliable results than those based on a conventional single titration method. The comprehensive evaluation of the measurement uncertainties for these assays was carried out, resulting in the establishment of the measurement methodologies for oxyanion standards.

Keywords: multipath titration, analysis, oxyanions, perchlorate ion, chlorate ion, chlorite ion and hypochlorite ions, drinking water quality assessment, instrumental analysis, standard solution, metrologically valid procedure, measurement uncertainty.

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