METHOD DEVELOPMENT AND OPTIMIZATION FOR THE DETERMINATION OF RARE-EARTH-METAL IONS BY CAPILLARY ZONE ELECTROPHORESIS

The separation of rare earth metal ions by capillary zone electrophore sis in the presence of creatinine as UV-absorbing background electroly te and the complexing agent 2-hydroxyisobutyric acid was investigated. The separation is mainly influenced by the pH of the buffer and the c oncentration of the complexing agent. Both parameters were used in a c entral composite design to determine optimal conditions. After modelli ng of the migration behaviour, the optimal conditions were selected us ing a multi-criteria approach in which separation coefficient (alpha), sensitivity and analysis time were considered. Finally, the method wa s validated regarding its detection limit, linearity and reproducibili ty.