Speciation of trace amounts of aluminium in environmental samples by cation-exchange FPLC-ETAAS

Cation-exchange fast protein liquid chromatography - electrothermal atomic absorption spectrometry (FPLC - ETAAS) was applied for the speciation of tr ace amounts of aluminium. An aqueous 8 mol dm(-3) NH4NO3 linear gradient el ution in 10 minutes enabled separation of positively charged monomeric alum inium species in aqueous solution. Separated aluminium species were collect ed in 0.5 cm(3) fractions and aluminium determined "off line" after fourfol d dilution by ETAAS. The ability of NH,NO, to completely decompose at low t emperature in the graphite tube during the ashing step enabled quantitative and reproducible determination of aluminium. After applying Chelex-100 res in in a cleaning procedure of the eluent, the eluent blank was very low (< 1.0 ng cm(-3) Al). When 1 cm(3) of sample was injected on the column resin, the limit of detection (3 s) for the separated aluminium species determine d by ETAAS was found to be 3 ng cm(-3). Good repeatability of measurement o f separated aluminium species (relative standard deviation +/-5%) was obtai ned under the recommended analytical conditions. The influence of some inor ganic and organic complexing ligands at pH values of 4.0 and 6.0 on the spe ciation of aluminium was also investigated. The method developed was succes sfully applied for the speciation of aluminium in soil extracts and natural water samples at ng cm(-3) levels.