Preparation of Chromatograhpy Matrices Having Thermoresponsive Polymer Brush Structure

We have prepared thermoresponsive chromatographic matrices by introducing poly(N-isopropylacrylamide) chains onto silica beads for separation of bioactive compound in aqueous media [1]. This system is highly useful to control function and properties of the stationary phase for high performance liquid chromatography (HPLC) by only change in column temperature, and has advantages in maintaining biological activity for peptides and proteins and reduced pollution by organic solvents. We have investigated the preparation and characterization of a series of thermoresponsive polymer modified surfaces as the chromatographic stationary phase. Properties of thermoresponsive modifier on the silica surfaces influence the separation efficiency. In addition, polymer grafting method has also significant importance, because graft conformation of PIPAAm on silica surfaces, determined by grafting method, greatly influences the temperature-responsive wettability changes and elution behavior of solutes [2,3]. In the present paper, we prepared high-density PIPAAm brushes on silica beads surfaces using surface-immobilized ATRP initiator in order to characterized the densely PIPAAm grafted silica beads as a chromatographic stationary phase (Figure 1). Property of densely PIPAAm grafted silica as a novel stationary phase is investigated with elution behavior of steroids and peptides.