The standard value of bromate in Japan is set to 0.01 mg/L by Ministry of Health, Labour and Welfare. Although the current analysis of bromate adopts ion chromatography with post column-adsorption photometry, liquid chromatography with mass spectrometry was added by the Ministry of Health, Labor and Welfare on April 1, 2017. In this application, RSpak JJ-50 2D was used for an LC/MS/MS analysis of bromate. JJ-50 is modified with quaternary ammonium functional group and it works as a multimode column (reversed phase + anion exchange). Bromate can be separated from other major anions, and the calibration curve of bromate shows good linearity respectively in the range from 0.001 to 0.02 mg/L. Furthermore, when 0.01 mg/L of bromate was added to tap water, additional recovery of bromate was almost 100%.


Sample : 5 μL
Standard solution
1. ClO₃^-, Chlorate 0.01 mg/L
2. NO₃^-, Nitrate 0.1 mg/L
3. BrO₃^-, Bromate 0.01 mg/L
4. Br^-, Bromide 0.1 mg/L
5. Cl^-, Chloride 0.1 mg/L
6. SO₄^2-, Sulfate 0.1 mg/L

Sample : 5 μL
Tap water
1. ClO₃^-, Chlorate
2. NO₃^-, Nitrate
3. BrO₃^-, Bromate
4. Br^-, Bromide
5. Cl^-, Chloride
6. SO₄^2-, Sulfate

Column       : Shodex RSpak JJ-50 2D (2.0 mm I.D. x 150 mm)
Eluent       : (A); 200 mM HCOONH4 aq./(B); CH3CN
               Linear gradient (High pressure);
               85 B % (0 min) → 85 B % (8 min) → 50 B % (9 min) → 50 B % (14 min) 
               → 85 B % (15 min) → 85 B % (20 min)
Flow rate    : 0.3 mL/min
Detector     : ESI-MS/MS (MRM Negative) for ClO3-, BrO3-
               ESI-MS (SIM Negative) for NO3-, Br-, Cl-, SO42-
Column temp. : 50 °C