Aluminum speciation by liquid chromatography concerning hydro- and geo-chemical aspects

The role of complexing ligands in reducing aluminum (Al) toxicity and in influencing Al transport in soils and waters has been recognized for some time though the strong complexes occurring in the environment have not been separated completely by chromatography or other analytical techniques. For that reason, ion chromatography using a newly developed combined size exclusion and cation exchange column was applied to the determination of Al and its fluoro, oxalate and citrate complexes and their distribution in a range of pH from 3 to 5. The species were detected via a post-column reaction with Tiron followed by UV photometry as well as atomic spectrometry using an on-line technique. With the cation exchange column used in this investigation, the separation of all the species formed by the complexing agents in a multiple ligand system can be realized. The total limit of detection for Al with photometric detection is 2 ng.