Influence of column temperature on the ion chromatographic separation of aluminum species Original Research Article

Ion chromatography using a combined size exclusion and cation exchange column was applied to the determination of aluminum and its fluoro, oxalate and citrate species. For the verification of an assumed disintegration of Al species during their ion chromatographic separation, the column temperature was varied from −10 to 55°C. The species were detected by post-column reaction with a Tiron based solution, followed by UV photometry as well as by on-line coupling to atomic spectrometry. The results showed that weaker neutral and negatively charged Al species based on ligands such as fluoride and oxalate are partly disintegrated during the chromatographic process. The disintegration of these species could be suppressed to a large extent utilizing column temperatures below 10°C. A significant effect of the column temperature on Al–citrate species was not observed. The agreement between speciation data determined experimentally by ion chromatography and by calculations based on stability constants became even better with decreasing column temperature and decreasing Al to ligand molar ratio.