Thermo-responsive columns for HPLC: The effect of chromatographic support and polymer molecular weight on the performance of the columns.

Recently a novel technique has been developed in chromatography, namely thermo-responsive chromatography. This employs the use of thermo-responsive polymers grafted onto pre-formed stationary phases for the separation of hydrophobic analytes. The resultant thermo-responsive silica exhibits temperature-controlled hydrophilic-hydrophobic properties. In this study, the themo-responsive polymers were grafted in situ into the pre-packed aminated silica columns. It was found that the molecular weight of the grafted thermo-responsive polymers should be optimized in order to obtain an efficient thermo-responsive column. Furthermore, within this study it was observed that the type of stationary phase (monolithic or packed beads) and the presence of mesoporosity in the system are important parameters influencing the final performance of the thermo-responsive column.