【摘 要】
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Poly (N-isopropylacrylamide) (PNIPAAm)-modified silica bead with varied grafting ratios was prepared via atom transfer radical polymerization (ATRP).The grafting ratios of PNIPAAm on silica surface we
【机 构】
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The school of Life Science,Beijing Institute of Technology,Beijing 100081,China
【出 处】
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第八届全国微全分析系统学术会议、第三届全国微纳尺度生物分离分析学术会议暨第五届国际微化学与微系统学术会议
论文部分内容阅读
Poly (N-isopropylacrylamide) (PNIPAAm)-modified silica bead with varied grafting ratios was prepared via atom transfer radical polymerization (ATRP).The grafting ratios of PNIPAAm on silica surface were controlled by the composition of the reaction solvent (water and isopropanol).The grafting ratios of PNIPAAm on surface were characterized by thermogravimetric analysis (TGA),and gel permeation chromatography (GPC),respectively.Our results showed that all of these stationary phases exhibit a lower critical solution temperature (LCST) of 32 oC.Grafting conformation on temperature-responsive property of stationary phase surface was investigated by evaluating the elution behavior of five steroids using water as mobile phase.The results showed that PIPAAm grafting ratio has a crucial influence on separation efficiency of thermosensitive chromatographic stationary phase.On the condition of the same density of the PNIPAAm,The lower grafting ratio of the PNPAAm on silica surface,the worse of the thermosensitivity and the degree of seperation.On higher ratio grafting surface,shorter retention time,narrower peak width was observed compared with lower ratio PNIPAAm grafting surface.This is because the hydrophobic interaction of the difference analyses with the higher ratio grafting chain is stronger than the lower one.
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