DETERMINATION OF CATIONS AND ANIONS BY CAPILLARY ELECTROPHORESIS COMBINED WITH SUPPRESSED CONDUCTIVITY DETECTION

Capillary electrophoresis combined with suppressed conductivity detection is a highly sensitive and selective method for the determination of UV-transparent ionic species. Using direct injection techniques (no electrostacking), minimum detection limits for common organic and inorganic ions are in the range of 1-10 ppb. Suppressors are made from short ion-exchange membrane capillaries and are placed between the separation capillary and the detector cell. The suppressor is placed in the destination vial, which contains regenerant and the ground electrode. The method is dependent on the presence of electroendoosmotic flow in the capillary to transport analyte and buffer ions through the suppressor.