Speciation of aluminium in forest soil extracts by size exclusion chromatography with UV and ICP-AES detection and cation exchange fast protein liquid chromatography with ETAAS detection

Aluminium speciation was studied in forest soil extracts by size exclusion chromatography SE. with UV and inductively coupled plasma-atomic emission spectrometric ICP-AES. detection and cation exchange fast protein liquid chromatography FPLC. with ETAAS detection. Size exclusion chromatography was performed on a Superdex HR75 10r30 column. Isocratic elution with 0.15 mol dmy3 NaCl in TRIS]HCl buffer pHs5.5. was applied over 100 min at a flow rate of 0.35 cm3 miny1. The chromatographic run was followed at 278 nm and separated Al species also determined ‘off line’ in 0.875 cm3 fractions by ICP-AES. The analytical procedure enabled speciation of high molecular weight Al complexes. Cation exchange FPLC was performed on a Mono S HR 5r5 column. Aqueous 8 mol dmy3 NH4NO3 linear gradient elution was applied over 10 min at a flow rate of 1 cm3 miny1. Separated Al species were collected in 0.5 cm3 fractions and Al determined ‘off line’ by ETAAS. The analytical procedure enabled speciation of some positively charged monomeric Al species. Negatively charged species were eluted with the solvent front. The combination of the two analytical techniques was successfully employed in speciation of Al in forest soil extracts. Water was used as an extracting solution. It was found experimentally that 80]95% of Al in aqueous extracts of forest soils exists in monomeric Al forms. Water soluble Al 30]40%. is bound to high molecular weight complexes with humic substances. The remaining monomeric Al in the low molecular weight fraction exists as AlF2q, Al-oxalate and Al-citrate species