Simultaneous Determination of Iodate Chlorite and Bromate in Bottled Drinking Water by Ion Chromatography with Post-Column Reaction and UV Detection

Iodate, chlorite and bromate in bottled water are disinfectant by-products (DBPs) from ozonation. The established methods for simultaneous determination of iodate, chlorite and bromate are mostly based on pre- or post-column chemical reaction in which the target compound was converted to another easily detectable species. However, the procedure suffers from several time-consuming reaction steps that involve multiple chemicals, or where the reagents themselves are toxic. In the present study, a rapid, highly sensitive, precise and accurate method was established, and a post-column reaction with sodium nitrite and acid solution of potassium bromide was employed to enhance sensitivity and to reduce interferences. Under optimized conditions, the method limits for iodate, chlorite and bromate were 0.5, 0.4 mu g/L and 0.1 mu g/L, respectively. Percentage recoveries of iodate, chlorite and bromate varied from 70.8% to 98.0%, 92.4% to 100% and 93.2% to 104.1% respectively with different spiked water samples. The proposed method was demonstrated for detecting the concentrations of iodate, chlorite and bromate in bottled water produced from different water sources. Results showed that severe bromate contamination was present in bottled mineral water purchased from Beijing supermarket, which used spring water or ground water as the sources.