SEPARATION AND INDIRECT DETECTION BY CAPILLARY ZONE ELECTROPHORESIS OF PPB (W W) LEVELS OF ALUMINUM IONS IN SOLUTIONS OF MULTIPLE CATIONS/

Solutions of multiple cations in aqueous solutions at concentrations a s low as 200 ppb were analyzed by capillary zone electrophoresis. Alum inum ions were cleanly separated from Li+, K+, Ca2+, Cr3+, Zn2+, Cu2+, and other ions less than 6 min after injection of the solution on a 5 0 cm x 50 mu m I.D. uncoated fused-silica capillary column at 15 kV. I ndirect detection at 204 nm was carried out using a pH 2.8 background electrolyte containing 5.2 mM ephedrine as a UV-absorbing co-ion and 4 .7 mM alpha-hydroxyisobutyric acid as a complexing counter ion. Mobili ties for Al3+ and 14 other complexed cations were determined for this electrolyte.