OPTIMIZATION OF DETECTION SENSITIVITY IN THE ANALYSIS OF INORGANIC CATIONS BY CAPILLARY ION ELECTROPHORESIS USING INDIRECT PHOTOMETRIC DETECTION

Capillary ion electrophoresis (Waters' trade name Capillary Ion Analysis, or CIA) is the subdivision of capillary zone electrophoresis in which the conditions for the separation are optimized for the analysis of inorganic or low-molecular-mass ions. The first reported separation of alkali, alkaline earth and transition metals by capillary ion electrophoresis, published in 1991 [LC . GC, 9 (1991) 634], showed the separation of these cations in under 10 min with mid-ppb detection limits and separation efficiencies of more than 100 000 theoretical plates. Detection sensitivity has since been improved by altering both hardware and electrolyte components. These alterations have resulted in a decrease in detection limits of more than an order of magnitude, making trace level analyses practical for many applications. The good reproducibility and linearity of this technique are also discussed.