Capillary methacrylate-based monoliths by grafting from/to ?-ray polymerization on a tentacle-type reactive surface for the liquid chromatographic separations of small molecules and intact proteins

Capillary methacrylate-based monoliths were prepared for the high performance liquid chromatography(HPLC) separation of both small molecules and large biomolecules. An efficient grafting from/to syntheticapproach was adopted introducing a network of activated sites in the inner wall surface using the newsilanization agent (N-trimethoxysilylpropyl)-polyethylenimine. Copolymerization of lauryl methacrylatemonomer and 1,6-hexanediol dimethacrylate cross-linker in the presence of porogenic solvents wasobtained under continuous gamma-ray exposure with high conversion yield. The morphology and porous structure of the resulting monoliths have been investigated by ScanningElectron Microscopy (SEM) and1H NMR cryoporosimetry. By chromatographic investigation, the newcapillary columns attested high kinetic performance (with efficiency larger than 100,000 theoreticalplate/m for small molecules at optimum mobile phase linear velocity of about 0.5 mm/s) and also excellentmechanical stability and repeatability.The new methacrylate-based monolithic capillary columns have been successfully employed for effi-cient reversed-phase separation of intact proteins and peptides.