Packing and stationary phase design for capillary electroendosmotic chromatography (CEC)

Reversed-phase stationary phases based on porous silica beads in the range 0.2-3 mu m have been prepared to study the dependency of electroosmotic flo w (EOF) on particle diameter. Additionally, the influence of the mobile pha se composition, i.e. organic modifier content, pH of buffer solution and co ncentration of buffer salt, on the magnitude of the electroosmotic flow vel ocity has been investigated. To perform separations in an aqueous acidic mo bile-phase, mixed mode stationary phases containing both alkyl chains and s trong cation-exchange groups have been applied.