氧化石墨烯修饰硅胶液相色谱填料的制备及色谱性能研究

摘要

通过层层自组装技术将石墨烯(GO)修饰到硅胶(SiO2)表面组装10次后,制备了氧化石墨烯修饰硅胶色谱填料(GO/SiO2-10).表面分析、元素分析和接触角分析均证实了氧化石墨烯被成功修饰到了硅胶表面.采用多环芳烃(PAHs)、不同取代基芳香化合物、有机酸和有机胺考察了填料的反相色谱分离性能.结果表明,PAHs和填料之间表现出π-π相互作用,PAHs的保留时间和色谱峰宽随着PAHs共轭结构的增大而增加;在仅用水做流动相条件下,不同取代基芳香化合物就可以在该填料上得到很好地分离;流动相的pH值对有机酸的分离有很大影响,调节流动相pH值,可以实现对有机酸的良好分离;有机胺和填料之间存在着电荷及π-π相互作用,在流动相中加入洗脱盐可以实现有机胺的良好分离.采用中性化合物和酚类化合物考察了该填料的正相色谱分离性能,中性化合物能在该填料上分离性能好,并且出峰顺序和中性化合物的π-电子体系的大小一致;由于GO/SiO2-10表面的羟基和羧基,该填料对酚类化合物也具有非常好的分离性能.该研究对于表面活性剂的分离和检查具有一定的实际应用价值.%Graphene oxide (GO) were layer-by-layer assembled onto silica microspheres to form GO/SiO2-10 stationary phase that were characterized by surface analysis, elemental analysis, and contact angle.The chromatographic properties of this kind of stationary phase was investigated by reversed-phase chromatography with polycyclic aromatic hydrocarbons (PAHs).Aromatic compounds with different substituents, organic acids and organic amines, were also investigated by normal-phase chromatography with hydroxybenzenes and normal compounds.The results showed that the interaction between PAHs and the new stationary phase was π-π interaction and retention times and peak withs of PAHs were influenced by the size of conjugation aromatic ring of PAHs, the lagger conjugated ring, the longer retention time and peak with.Using acetonitrile/water mixture as mobile phase, 4 kinds of PAHs can be well separated on GO/SiO2-10 column.Aromatic compounds with different substituents can be well separated on the GO/SiO2-10 column only using water as mobile phase.The pH of the mobile phase played an important role on retention of organic acids.Decreasing the pH of the eluent can adjust the ks of organic acids and then to make a well separation.The interaction between organic amines and the stationary phase were electrostatic attraction and π-π interaction, so organic amines can be separated as well in the addition of elute salt in mobile phase.Neutral compounds can be well separated on this new stationary phase in normal phase, and their elute orders are according to their л-electron systems.Due to the presence of hydrophilic acidic groups on the surface of GO/SiO2-10, this new stationary phase had an evident advantage in separation of hydroxybenzenes in normal phase chromatography.