CAPILLARY ELECTROCHROMATOGRAPHIC SEPARATION OF BASIC COMPOUNDS WITH BARE SILICA AS STATIONARY-PHASE

The feasibility of capillary electrochromatography (CEC) was demonstra ted using capillary columns packed with 3-mu m silica particles and a mobile phase of organic-aqueous buffer system. The retention mechanism s of basic compounds were explored. Preliminary results indicated that the separation of the basic compounds in the CEC system involved mult iple retention mechanisms including reversed-phase, cation-exchange as well as normal-phase mechanisms. In addition, electrophoretic mobilit y of the solutes also contributed to retention. The effects of experim ental parameters such as the volume fraction of the organic modifier, pH value and ionic strength of the buffer on the retention behaviours of the solutes were investigated. A comparison of differences between CEC and CE of separations was also discussed. (C) 1998 Elsevier Scienc e B.V. All rights reserved.