A reversed phase/hydrophilic interaction/ion exchange mixed-mode stationary phase for liquid chromatography

A reversed phase (RP)/hydrophilic interaction (HILIC)/ion exchange (IEX) mixed tri-mode stationary phase (TMSP) has been prepared via a divergent synthesis scheme starting from propylamine on silica then by amine-epoxy reactions with 1,4-butanedioldiglycidyl ether and tertiary amines (N,N-dimethyldecylamine, DMDA). Its retention mechanism was found to follow RP/HILIC/IEX mixed-mode. The stop-flow test revealed that TMSP had good compatibility with 100% aqueous mobile phase. It demonstrated effective separation towards several kinds of compounds or drug molecules and their counterions within a single run.