Bromate determination in water samples – comparison of IC and IC/MS methods

The problem: low bromate limits

During recent years, the necessity to determine bromate in drinking and mineral waters has increased significantly because bromate is a potential carcinogen. Bromate is generated by the oxidation of bromide traces during water disinfection, for example by ozonization. The German regulations concerning drinking water prescribe a temporary limit of 25 µg/L, which will be lowered to 10 µg/L in 2008. The processing of mineral waters suffers from similar problems. Here, the pertinent regulations, dating from 1st July 2004, prescribe a limiting value of 3 µg/L.

The application: Comparison of IC and IC/MS methods

The determination of bromate in drinking, mineral and table waters is a highly topical analytical problem that has been solved applying ion chromatography. Four different methods were used in combination with internationally accepted standards. The different detection methods are compared in terms of detection limits and application possibilities. The combined IC/MS method proves to be the most sensitive technique; at the same time it offers the possibility to determine additional water sample constituents.

Various highly efficient methods based on ion chromatography have been developed for the determination of bromate. Special sample preparation steps, such as lowering the chloride concentration of the matrix, are not required. In each case, the separation of the bromate occurs on an anion exchanger column. The following detection methods have been used:

• Conductivity detection after chemical suppression
• MS detection
• Post-column reaction with o-dianisidine followed by VIS detection
• Post-column reaction with iodide followed by UV detection

Read the details of this application (pdf, Info Center).