Determination of Bromate and Bromide in Seawater by Ion Chromatography, with an Ammonium Salt Solution as Mobile Phase, and Inductively Coupled Plasma Mass Spectrometry

Abstract

A method has been developed for determination of bromate and bromide in water containing high concentrations of chloride (e.g. seawater). Separation of bromate and bromide on an anion-exchange column was followed by ICP–MS detection. To reduce interference of chloride with determination of bromate and bromide, and to avoid clogging, ammonium salts, for example NH4H2PO4, (NH4)2HPO4, (NH4)2CO3, and NH4NO3 were examined as mobile-phase components. It was found that mobile phase containing 20 mM NH4NO3 at pH 5.80 was compatible with the anion-exchange column and enabled reasonable resolution and separation of bromate and bromide within 7 min. Detection limits for bromate and bromide ranged from 2.0 to 3.0 μg L−1 for direct injection of 50 μL sample without matrix elimination. The proposed method was used for analysis of bromate and bromide in seawater.