Fast separation of pyrimidine derivatives by capillary electrochromatography on ion-exchange/reversed-phase mixed-mode stationary phases

This work describes the use of mixed-mode stationary phases which exhibit b oth strong ion-exchange (either cation-exchange, SCX, or anion-exchange, SA X) and reversed-phase chromatographic characteristics in capillary electroc hromatographic separations of pyrimidine derivatives. Different packing mat erials, namely C-6, SCX/C-6 and SAX/C-6, were compared and the influence of the composition of the carrier electrolyte (concentration of acetonitrile and pH) on the retention behavior of the selected solutes was investigated. A separation of all eight pyrimidine derivatives could be obtained on a 6. 5 cm column packed with the SAX/C-6 stationary phase in less than 3 min, wi th good peak shapes and efficiencies in the range 39 000 to 81 000 plates p er meter. (C) 2001 Elsevier Science B.V. All rights reserved.