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Potassium Bromate Assay by Redox Titrimetry Using Arsenic Trioxide



J M. Smeller, Stefan D. Leigh


Bromate, a disinfectant, is one of the analytes of interest in wastewater analysis. Environmental laboratories have a regulatory need for their measurements to be traceable to NIST standards. Bromate is not currently certified as a NIST Standard Reference Material (SRM). A traceable assay of potassium bromate (KbrO3) is needed. KbrO3 was dissolved in water and assayed by redox titrimetry using arsenic trioxide (As2O3). A nominal (0.1 g) sample of As2O3 was dissolved in 10 mL of 5 mol/L sodium hydroxide. The solution was acidified with hydrochloric acid, and about 95 % of the KBr(3 titrant was added gravimetrically. The end point was determined by addition of dilute (1:3) titrant using an automated titrator. The KbrO3 assay was determined to be 99.76 % ¿ 0.20 %. The estimated uncertainty considered the titrations of three independently prepared KbrO3 solutions.
Journal of Research (NIST JRES) - of
Report Number


Smeller, J. and Leigh, S. (2003), Potassium Bromate Assay by Redox Titrimetry Using Arsenic Trioxide, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 13, 2024)


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Created January 31, 2003, Updated October 12, 2021