Simultaneous determination of Cr(III) and Cr(VI) in ground and drinking waters by IC-ICP-MS

The coupling of ion chromatography (IC) and inductively-coupled plasma mass spectrometry (ICP-MS) provides a powerful tool for the simultaneous determ ination of Cr(III) and Cr(VI) in water samples. The experimental set-up of the technique is described in detail and performance data are given, whereb y detection limits of 0.1 mu g/l could be achieved for both chromium specie s without preconcentration. With this method, a complete analysis can be do ne in less than 3 minutes. In order to improve the repeatability of the met hod, Rh(III) as internal standard is used. Stability of the two chromium sp ecies in water turned out to be a major problem and optimal conditions for storage were determined. For real water samples storage at 4 degrees C in t he dark at neutral pH and analysis as fast as possible is recommended. The application of the IC-ICP-MS technique to real water samples and the compar ison to another, more time-demanding and less sensitive method proves the c apacity of the method.