Preparation and Characterization of Temperature-responsive Porous Monoliths
A new temperature-responsive porous monolith has been prepared by surface-initiated activators generated by electron transfer atom transfer radical polymerization (AGET ATRP) grafting poly(N-isopropylacrylamide) (PNIPAAm) within the pores of the porous polymer monolith. The grafting copolymerization was carried out by a method based on a continuous flow-through technique without special deoxygenation procedure needed in the general ATRP. The addition of ascorbic acid could counteract the oxidation effect of oxygen diffusing into the reaction system. The resulting grafted monolith was characterized by a mercury intrusion method and the size of macropore was 3.65 μm, which was suitable for flow through the monolith for HPLC. The thermally responsive property of the grafted monolith was evaluated by HPLC using steroids with various hydrophobicities as probes. Through determination of retention factor of each steroid on the grafted monolith at different temperatures using water as mobile phase, it was found that the slope of the plot of retention factor of each steroid versus the temperature changed around the low critical solution temperature (LCST, 32 ℃) of PNIPAAm in water. It was relative to the grafted PNIPAAm temperature sensitivity that a hydrophobic and hydrophilic alternation would take place around its LCST.Based on this thermally responsive property, the grafted monolith was used as stationary phase for HPLC and to separate the steroids using water as mobile phase by changing the column temperature. As a mobile phase, water is much better than organic solvents concerning the environment.
作 者： ZHANG, Rongyue QI, Li XIN, Peiyong YANG, Gengliang CHEN, Yi 作者单位： ZHANG, Rongyue,XIN, Peiyong(Beijing National Laboratory of Molecular Science, Laboratory of Analytical Chemistry for Life Science,Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China;Graduate School, Chinese Academy of Sciences, Beijing 100049, China)QI, Li,CHEN, Yi(Beijing National Laboratory of Molecular Science, Laboratory of Analytical Chemistry for Life Science,Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China)
YANG, Gengliang(College of Pharmacy, Hebei University, Baoding, Hebei 071002, China)
刊 名： 中国化学（英文版） SCI 英文刊名： CHINESE JOURNAL OF CHEMISTRY 年，卷(期)： 2009 27(11) 分类号： O6 关键词： temperature-responsive monolith poly(N-isopropylacrylamide) atom transfer radical polymerization,HPLC steroid