Ultra-trace determination of bromate in drinking waters by means of microbore column ion chromatography and on-line coupling with inductively coupled plasma mass spectrometry

A method for ultra-trace determination of bromate in drinking waters using on-line coupling of ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS) has been developed. The method utilizes the microbore column technique in combination with a self-made high-capacity and high-performance anion-exchanger. The high capacity of the separation column as well as an optimized elution system based on NH4NO3 allows a direct analysis of almost every water sample without matrix elimination. Even more, the use of large injection volumes is possible. No trace enrichment is required because of the sensitivity of ICP-MS detection. The effort on sample pretreatment is therefore reduced to zero. The method detection limits for bromate in the drinking and mineral waters investigated are in the 50–65 ng/l range, corresponding to absolute detection limits of 44–58 pg. Retention behaviour of bromate as well as signal-to-noise (SNR) and signal-to-background (SBR) ratios are dependent on the sample composition. The within-run imprecision of the presented IC-ICP-MS coupling is 5% at a concentration level of 500 ng/l bromate. The time spent on a complete analysis is 8–15 min, depending on the bromide content of the sample. Considering sensitivity as well as imprecision and short analysis times, the described IC-ICP-MS coupling is well suited for precise routine analysis of bromate in drinking waters at sub-μg l−1-levels.