Synthesis of boronic acid-immobilized monodispersed porous polymer resins using a templating polymerization technique, and their application to packings for separation of saccharides

硼酸与糖的顺式二醇形成稳定的环状酯，因此用于分离核苷、核苷酸和糖化蛋白，如糖化血红蛋白。在这些研究中，硼酸与载体如硅胶共价结合。采用高分子树脂进行分离。但由于在碱性溶液中的不稳定性，硅胶填充柱的pH范围受到了限制。另一方面，在传统的制备方法中，聚合物树脂的粒度不均匀是不可避免的，这降低了色谱柱的分辨效率。为了分离糖类和糖缀合物，我们采用基于模板技术的聚合方法制备了两种单分散硼酸固定化多孔苯乙烯-二乙烯基苯共聚物颗粒。采用粒径为5 μ m的聚合物颗粒作为高效液相色谱的固定相。HPLC分离结果表明，在pH为1.3 ~ 11.9范围内，硼酸固定化聚合物树脂中保留了核糖、talose和idose。这些糖在水溶液中以呋喃糖形式存在，因此呋喃糖形式可能在硼酸和糖之间的复合物形成中起重要作用。另一方面，采用粒径为20 μ m的聚合物颗粒固相萃取葡萄糖、塔洛糖和神经节苷脂G^<M1>。然而，没有观察到这些化合物的保留。结果表明，固相萃取对聚合物表面硼酸基团的固定化要求较高。

Boronic acids form stable cyclic esters with cis-diols of saccharides, and therefore are used in the separation of nucleosides, nucleotides, and glycated proteins such as a glycated hemoglobin. In these investigations boronic acids covalently bound to carriers such as silica gel. and polymer resins were used for the separation. However, pH range of silica gel packed column has been limited by the unstability in alkaline solution. On the other hand, the nonuniformity in particle size of the polymer resins is unavoidable in the conventional preparation method, and lowers the resolution efficiency of a chromatographic column.For separation of saccharides and glycoconjugates, we prepared two types of monodispersed boronic acid immobilized porous styrene-divinylbenzene copolymer particles using a polymerization method based on a templating technique. The polymer particles with 5 μ m particle size was used as the stationary phase for high-performance liquid chromatography. The results of HPLC separation of aldohexoses and aldopentoses revealed that ribose, talose and idose were retained in boronic acid immobilized polymer resins in the pH range of 1.3 〜 11.9. These saccharides exist considerably as a furanose form in an aqueous solution, and therefore, a furanose form probably plays important role in the complex formation between a boronoic acid and saccharides. On the other hand, the solid phase extraction by the polymer particles with 20 μ m particle size was applied to glucose, talose and ganglioside G^<M1>. However no retention with these compounds was observed. This result shows that higher extent of immobilization with boronic acid groups on the polymer surface was required for the solid phase extraction.