A　porous　zwitterionic　monolith　was　prepared　by　in　situ　covalent　attachment　of　lysine　to　a　γ-glycidoxypropyltrimethosysilane-modified　silica　monolith.　The　prepared　column　was　used　to　perform　neutral　and　ionized　solutes　separations　by　pressurized　(pCEC).　Due　to　the　zwitterionic　nature　of　the　resulting　stationary　phase,　the　monolithic　column　provided　both　electrostatic　attraction　and　repulsion　sites　for　electrochromatographic　retention　for　ionized　solutes.　Separation　of　several　nucleotides　was　investigated　on　the　monolithic　column.　It　was　shown　that　the　nucleotides　could　be　separated　based　on　hydrophilic　and　electrostatic　interactions　between　the　stationary　phase　and　analyte.　Besides,　the　separation　property　of　the　zwitterionic　silica　monolith　was　compared　with　the　use　of　diamine-bonded　silica　monolith　as　stationary　phase.　As　expected,　the　lysine　monolith　exhibited　a　lower　retention　for　the　five　nucleotides,　which　was　due　to　the　dissociation　of　the　external　carboxylic　acid　groups,　leading　to　electrostatic　repulsion　with　negatively　charged　solutes.　Under　the　same　experimental　conditions,　separation　of　the　five　nucleotides　on　the　zwit-terionic　column　was　in　less　than　8　min,　while　that　on　the　diamine　column　was　in　approximately　60　min.　©　2010　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA.