Under the Ordinance on Water Quality Standards (MHLW Ministerial Ordinance No. 101, May 30, 2003), the standard value for bromate is set at ≤ 0.01 mg/L. In addition, the official methods in “Methods Prescribed by the Minister of Health, Labour and Welfare Based on the Provisions of the Ordinance on Water Quality Standards” (MHLW Notification No. 261, July 22, 2003; last amended by Notification No. 87*, March 28, 2017) include “Table 18: Ion Chromatography–Post-Column Absorptiometry Method”, and “Table 18-2: Liquid Chromatography–Mass Spectrometry (LC–MS/MS)” newly added bromate analysis. This method mentions using a column packed with silica or polymer-based gels modified with anion‑exchange group, or a column offering equivalent or superior separation performance. Using RSpak JJ-50 2D, a multimode (reversed phase and anion exchange modes) column modified with quaternary ammonium group, we analyzed standard solutions of halogen oxides and common anions, as well as tap water. Under the described conditions, bromate was resolved from other major anions. The calibration curve for bromate showed high linearity over 0.001 to 0.02 mg/L. When tap water was spiked with bromate at 0.01 mg/L, the recovery was approximately 100%.
**Target analyte in Table 18-2 includes bromate.
Refer to "LC/MS/MS Analysis of Chlorate and Bromate According to Japanese Water Supply Act (JJ-50 2D)".

*The version at the time of the application acquisition.

Sample: 5 µL
Standard solution

1. 1.ClO₃^-, Chlorate 0.01 mg/L
2. 2.NO₃^-, Nitrate 0.1 mg/L
3. 3.BrO₃^-, Bromate 0.01 mg/L
4. 4.Br^-, Bromide 0.1 mg/L
5. 5.Cl^-, Chloride 0.1 mg/L
6. 6.HSO₄^-, Hydrogen sulfate 0.1 mg/L

Sample: 5 µL
Tap water

1. 1.ClO₃^-, Chlorate
2. 2.NO₃^-, Nitrate
3. 3.BrO₃^-, Bromate
4. 4.Br^-, Bromide
5. 5.Cl^-, Chloride
6. 6.HSO₄^-, Hydrogen sulfate