Analytical Method for Bromic Acid in Drinking Water by LC/MS/MS Using Multi-mode Column

Analytical method for bromic acid in drinking water was examined by liquid chromatography/tandem mass spectrometry (LC/MS/MS). For the purpose of bromic acid which is the high polarity other ionic compounds are properly separated on chromatograms. We were investigated measurement conditions using a multi-mode column (reverse phase + anion-exchange) by introducing a quaternary ammonium group. Further, we have verified the linearity of the calibration curves, the selectivity, the accuracy (recovery) of this analytical method from the data of the recovery test in drinking water. Bromic acid may be properly separated from chloric acid, nitrate ion, bromide ion, chloride ion and sulfate ion using a multi-mode column. The peak shape of bromate ion was good by using a multi-mode column. Also, the calibration curve of bromate showed good linearity in the range of 0.1 – 10 μg L−1. The repeatability (0.1 μg L−1, n = 5) was below 6.11 %. In addition, the repeatability (4.13 %), and intermediate precision (5.16 %) and the accuracy (98.4 %) for bromate acid obtained by the recovery tests in drinking water (1 μg L−1, n = 5, 5 days) were satisfied based on the criteria in the guideline for the validation of testing method in drinking water, which has been notified by the Ministry of Health, Labour and Welfare, Japan.