Anionenanalytik mit der On-line-Kopplung von Ionenchromatographie und induktiv gekoppelter Plasma-Massenspektrometrie

The on-line coupling of ion chromatography and ICP-MS was used for trace analysis of inorganic anions in aqueous solution. A method for the simultaneous determination of up to 15 anions within 35 min was developed. Different stationary phases, – latex anion exchangers, grafted and surface-functionalized materials, were investigated and their separation characteristics were compared. The IC-ICP-MS system was successfully applied to analyze bromide, bromate, iodide and iodate in mineral water samples achieving detection limits of 0.1 µg/L, 0.07 µg/L, 0.15 µg/L and 0.05 µg/L respectively. Germanium dioxide added directly to the aqueous ammonium nitrate eluent was found to be well-suited as an internal standard for bromine and iodine species. The measured continuous germanium signal serves for real-time correction of non-specific interferences and also as a tool for system diagnostics. It was shown that the signal ratio of analyte-to-GeO2 for bromine- and iodine-containing analytes remains unaltered to a large extent despite changed system parameters. Thus a calibration with high long-term-stability over several weeks is made possible allowing quantification without time-consuming daily measurement of calibration series.