Speciation of trace amounts of aluminium in percolating water of forest soil by online coupling HPLC-ICP-MS

Procedures were developed for the speciation of trace amounts of aluminium present in percolating water of forest soil by online coupling of different chromatographic separation methods to an ICP-MS detection system. Inorganic and organic aluminium species were fractionated on a cation exchange column IONPAC CG12 (10-32). Phytotoxic polymeric aluminium hydroxides, as e.g. Al-13 (AlO4Al12(OH)(24)(H2O)(12)(7+)), were determined using pyrocatechol violet (PCV) as a species dependant complexing reagent prior to the cation exchange step. Size fractionation of the organic aluminium species was obtained by size exclusion chromatography using the columns Superdex-75-HR 10/30 and Superdex-Peptide-HR 10/30. Validation of the speciation procedures proved that online coupling HPLC to the element selective and sensitive ICP-MS detection system leads to low detection limits of 0.3-0.6 mu g/L and high precision and reproducibility (1.2-3.5%) of the speciation procedures. Speciation data determined for aluminium in a percolating water of the Zierenberg catchment are given.