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采用巯基-烯烃点击反应制备了一种新型聚丙烯酰胺键合烯基修饰硅胶的亲水色谱固定相。丙烯酰胺与二硫代苯甲酸苄酯通过可逆加成-断裂链转移(RAFT)反应合成聚合物。在甲苯中,3-异氰酸酯丙基三甲氧基硅烷、丙烯胺和吡啶反应后,再与硅胶反应制备烯基修饰硅胶(EUS)。在甲醇中,以2,2-偶氮二异丁基脒盐酸盐为引发剂,被硼氢化钠还原的聚丙烯酰胺与EUS于55℃反应48 h,键合上巯基活化的聚合物。利用元素分析和红外光谱的方法对固定相TE-UPAM(Thiol-ene urea polyacy(amide))进行表征,含碳量与EUS相比有所增加,在1636和1570 cm!1处存在多重酰胺键红外特征峰。考察了流动相中水含量、盐浓度和p H值的变化对极性化合物保留时间的影响。结果表明,保留时间随水含量的增加而减小;中性和碱性化合物保留时间随盐浓度的增大而延长,在p H 3.3~4.8范围内,碱性化合物的保留时间随p H的降低而缩短,均与酸性化合物相反。固定相TE-UPAM在亲水模式下与传统硅胶固定相比较,更好地分离了7种核苷和碱基,再通过对寡糖的分离,表明此固定相分离极性化合物的巨大潜力。
A new hydrophilic stationary phase of polyacrylamide-bonded alkenyl modified silica gel was prepared by thiol-olefin click reaction. Acrylamide and benzyl dithiobenzoate were synthesized by reversible addition-fragmentation chain transfer (RAFT) reaction. In toluene, 3-isocyanate propyltrimethoxysilane, acrylamines and pyridine reaction, and then reacted with silica gel to prepare alkenyl modified silica gel (EUS). In methanol, polyacrylamide reduced with sodium borohydride using 2,2-azobisisobutylamidine hydrochloride as an initiator was reacted with EUS at 55 ° C for 48 h to bond the thiol-activated polymer. The phase of TE-UPAM (Thiol-ene urea polyacylamide) was characterized by elemental analysis and infrared spectroscopy. The carbon content increased compared with that of EUS. There were multiple amide bonds at 1636 and 1570 cm Infrared characteristic peak. The influence of the change of water content, salt concentration and p H value in the mobile phase on the retention time of the polar compounds was investigated. The results showed that the retention time decreased with the increase of water content. The retention time of neutral and basic compounds increased with the increasing of salt concentration. The retention time of basic compounds with p H of 3.3 ~ 4.8 ranged from Reduce and shorten, are the opposite of acidic compounds. The stationary phase TE-UPAM isolated seven nucleosides and bases better in the hydrophilic mode compared to the conventional silica gel immobilization, and the separation of the oligosaccharides indicated the great potential of the polar phase separation of the stationary phase.