功能化磁性微粒的合成与表征

Synthesis and characterization of functional Fe_3O_4 magnetic particles

以3 氨丙基三甲氧基硅烷与Fe3O4纳米粒子反应,制备了超顺磁性、表面修饰—NH2的功能化磁性微粒,带有氨基的磁性微粒进一步与戊二酸酐反应,可转化为—COOH修饰的功能化磁性微粒.利用X射线衍射、红外光谱、激光粒度散射仪等对磁性Fe3O4粒子以及两种功能化磁性微粒进行定性表征,建立了线性电位滴定和电导滴定的方法分别对磁性复合微粒表面—NH2和—COOH的量进行定量分析.结果表明,功能化磁性复合微粒的平均粒径为3～5μm,红外光谱分析结果中显示了功能基团—NH2和—COOH的特征峰谱,线性电位滴定测定功能化磁性微粒—NH2含量为400±50μmol/g,电导滴定法测定—COOH含量为380±50μmol/g.

The superparamagnetic Fe_3O_4 particle is prepared by chemical co-precipitation of Fe(Ⅱ) and Fe(Ⅲ) ions in alkaline medium. the —NH_2 group is modified on the Fe_3O_4 particle surface via silanization by reagent (γ-aminepropyltrimethoxysilane). Bifunctional reagent glutaricanhydride is used to react with the —NH_2 group on Fe_3O_4 particle and the —COOH terminal magnetic particles is obtained. IR, XRD and LPSA are used to characterize these two kinds of particles. The functional groups (—NH_2 and —COOH)are determined by linear potentiometric titration and conduometric titration method separately. The result shows that these particles have effective response to an external magnet, the average diameter of particles is from 3 to 5 μm mostly, the concentration of groups(NH_2 and —COOH) are 400±50 μmol/g, 380±50 μmol/g respectively. The functional Fe_3O_4 particle could be used in coupling antibody and oligonucleids, target drug carriers, separation and purification of DNA, cell sorting, immobilized enzyme etc.