SPECIATION OF CHROMIUM IN WASTE-WATERS BY COUPLED-COLUMN ION CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

An application of coupled column ion chromatography (IC)-inductively c oupled plasma mass spectrometry (ICP-MS) is presented for speciation o f chromium in waste waters. By coupling an anion column with a cation column, both the cationic Cr(III) and anionic Cr(VI) species can be an alyzed with detection limits below 0.5 mu g/l. The separation of the i nterfering ions (chloride, chlorate, perchlorate, sulphate, sulphite, sulphide, thiosulphate, carbonate, cyanide and some organic compounds) from the chromium peaks is discussed, and the use of different chromi um isotopes for data acquisition is compared. Based on the results, m/ z 52 was considered as an ideal isotope for speciation of chromium in waste waters by the coupled column IC-ICP-MS, because it did not suffe r from polyatomic interferences and due to the high sensitivity for ch romium. The analysis of the waste water samples should be performed as soon as possible after sampling according to the stability tests of t he species.