SPECIATION OF ALUMINUM USING CAPILLARY ZONE ELECTROPHORESIS WITH INDIRECT UV DETECTION

Capillary zone electrophoresis was evaluated as a method for the speci ation of aluminum in aqueous solution using indirect UV absorption det ection. Fluoro- and oxalatoaluminum complexes appeared as sharp and we ll-defined peaks within the electropherogram of aluminum standard solu tions when the appropriate ligand was added. Simultaneous separation o f these inorganic and organic aluminum species was achieved with good resolution in a single analytical run within 5 min. Indirect UV detect ion was achieved at 214 nm with a background electrolyte buffer contai ning 5 mM imidazole. The average limit of detection was about 10 nM fo r uncomplexed and complexed aluminum species. Excellent agreement betw een experimental and theoretical species concentrations (via the therm odynamic speciation model SOILCHEM) was obtained for solutions with va rying ligand/aluminum mol ratios and pH values.