基于硅胶整体材料研磨颗粒的多功能聚乙二醇键合固定相的制备及其在高效液相色谱多模式分离中的应用

Preparation of a versatile polyethylene glycol-bonded stationary phase based on silica monolith particles and its application in multi-modal separation in high performance liquid chromatography

研究通过对溶胶-凝胶法制备的硅胶整体材料进行研磨、浮选、假晶相转换和水热处理,最终获得了粒径为2~5μm、孔径为20~60 nm的硅胶颗粒。利用部分含氟的阴离子表面活性剂Capstone FS-66和常用的阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)组成的双胶束模板体系对硅胶基质进行假晶相转换处理;再采用碳酸钠溶液水热处理的方式,进一步扩大孔径。用扫描电镜(SEM)和N2吸附-解吸等温线测量对扩孔处理前后的硅胶整体材料研磨颗粒进行表征,结果清楚地显示了处理前后的形貌变化和差异。随后将含有长链聚乙二醇(PEG)的硅烷键合到扩孔后的硅胶颗粒表面,分别利用元素分析、红外光谱以及热重分析对固定相进行表征,并对固定相进行色谱性能评价。对键合固定相的元素分析和热重分析数据进行分析表明,硅胶表面键合PEG的含量约为8%。研究揭示了利用假晶相转换法与碳酸钠溶液水热处理和长链PEG硅烷修饰的硅胶整体材料颗粒在尺寸排阻色谱分离蛋白质方面的良好分离效果。同时进一步的高效液相色谱评价结果表明,该键合固定相还可用于疏水作用色谱模式分离核糖核酸酶A和溶菌酶,以及可用于亲水作用色谱模式分离吡啶甲酸、左旋多巴、三聚氰胺和邻苯二酚等极性比较强的化合物。研究显示了PEG键合固定相具有多功能性,及其在多模式高效液相色谱分离中的应用潜力。

Silica monolith particles with sizes of 2-5μm and pore sizes of 20-60 nm were obtained by grinding,flotation,pseudomorphic transformation,and hydrothermal treatment of the silica monolith prepared by the sol-gel method.The pseudomorphic transformation was performed with a dual micellar templating system consisting of Capstone FS-66,a partially fluorinated anion surfactant,and cetyltrimethylammonium bromide(CTAB),a commonly used cation surfactant.Hydrothermal treatment with a sodium carbonate solution was adopted to further expand the pore size.Scanning electron microscopy(SEM)images and N2 adsorption-desorption isotherm measurement results of the silica monolith particles before and after the treatments clearly demonstrated the changes in morphology caused by these treatments.Afterward,a long-chain polyethylene glycol(PEG)containing silane was bonded on the surface of the as-prepared particles,and the resulting products were characterized by elemental analysis and FT-IR spectroscopy analysis,and evaluated by high performance liquid chromatography(HPLC).Elemental analysis and thermogravimetric analysis(TGA)of the bonded stationary phase revealed that the bonding amount of PEG on the silica surface is about 8%.It has been shown that silica monolith particles can be treated and modified for the separation of proteins in size exclusion chromatography mode.It is also demonstrated that the bonded stationary phase can be used for the separation of ribonuclease A and lysozyme in hydrophobic interaction chromatography mode,and for the separation of highly polar compounds(picolinic acid,levodopa,melamine,and catechol)in hydrophilic interaction chromatography mode.The results indicate the versatility of the PEG-bonded stationary phase and its promising application to multi-modal separation in HPLC.