Photografted fluoropolymers as novel chromatographic supports for polymeric monolithic stationary phases

In this study, porous polymer monoliths were in situ synthesized in fluoropolymers tubing to prepare microbore HPLC columns. To ensure the formation of robust homogeneous polymer monoliths in these housing supports, the inner surface of fluoropolymer tubing was modified in a two-step photografting process. Raman spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the inner poly(ethylene-co-tetrafluoroethylene) (ETFE) wall and the subsequent attachment of a monolith onto the wall. Poly(glycidyl methacrylate-co-divinylbenzene), poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) and poly(styrene-co-divinylbenzene) monoliths were in situ synthesized by thermal polymerization within the confines of surface vinylized ETFE tubes. The resulting monoliths exhibited good permeability and mechanical stability (pressure resistance up to 9 MPa). The chromatographic performance of these different monolithic columns was evaluated via the separation of alkyl benzenes and proteins in a conventional HPLC system.