高碳含量新型亚微米无孔二氧化硅材料的修饰方法及其在反相加压毛细管电色谱平台上的应用  

Novel submicron nonporous silica material modification with high carbon content and its application in reversed-phase pressurized capillary electrochromatography

作　　者：夏子航 Soumia CHEDDAH 王薇薇[1] 王彦[1] 阎超[1] XIA Zihang;Soumia CHEDDAH;WANG Weiwei;WANG Yan;YAN Chao(School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China)

机构地区：[1]上海交通大学药学院,上海200240

出　　处：《色谱》2022年第1期88-99,共12页Chinese Journal of Chromatography

基　　金：国家自然科学基金项目(81874307,21874088);上海市科委“科技创新行动计划”(18142200700,19142203100,20142200400,18490731500);细胞工程及抗体药物教育部工程研究中心开放课题(19X110020009-005);上海交通大学“新进青年教师启动计划”(19X100040029).

摘　　要：亚微米无孔二氧化硅(NPS)材料具有小粒径及表面光滑形状规整等特点,是一种性能优异的色谱材料,但其存在比表面积小、修饰效率低的问题。针对此设计了一种具有高碳含量的修饰方法:以3-缩水甘油基氧基丙基三甲氧基硅烷(GPTS)作为硅烷偶联剂,聚乙烯亚胺(PEI)作为聚合物包覆层,并以硬脂酰氯修饰得到一种氨基包覆的具有C_(18)碳链结构的新型亚微米无孔二氧化硅材料(C_(18)-NH_(2)-GPTS-SiO_(2))。利用元素分析、傅里叶变换红外光谱、Zeta电势等进行表征,证明C_(18)-NH_(2)-GPTS-SiO_(2)固定相的成功制备。该修饰方法将NPS的碳含量从0.55%提高到了8.29%,解决了过往NPS材料采用十八烷基氯硅烷等传统C_(18)修饰方法时碳含量较低的问题。此外,^(29)Si固体核磁显示:NPS与多孔二氧化硅(PS)微球相比不仅存在孔结构与比表面积区别,且表面硅羟基种类也不同。16%的PS微球硅原子带有一个硅羟基(孤立硅羟基,Q_(3))、19%带有两个硅羟基(偕硅羟基,Q_(2));而NPS微球不存在偕硅羟基,仅有30%硅原子处于孤立硅羟基状态。实验发现NPS微球存在硅羟基数量低且缺少偕硅羟基的特点,导致NPS材料表面修饰活性低,难以通过简单一步反应获得高碳含量。采用不同疏水物质如苯系物、多环芳烃对色谱性能及保留机理进行研究,结果表明C_(18)-NH_(2)-GPTS-SiO_(2)色谱柱符合反相作用机理。氨基的包覆改变硅球表面电性,提高了NPS材料运用于加压毛细管电色谱平台(pCEC)时的电渗流大小,施加+15 kv时,显示出良好的分离能力,证实了C_(18)-NH_(2)-GPTS-SiO_(2)材料通过多步反应提高碳含量的修饰方法在pCEC平台上应用的优异性。Submicron nonporous silica(NPS) materials feature small particle sizes, smooth surfaces, and regular shapes. They also exhibit excellent performance as a stationary phase;however, their use is limited by their low specific surface area and low phase ratio. Therefore, a novel surface modification strategy tailored for NPS microspheres was designed, involving a multi-step reaction. 3-Glycidyloxypropyltrimethoxysilane(GPTS) was first grafted onto NPS particles as a silane coupling agent. Polyethyleneimine(PEI), a high-molecular-weight polymer, was then coated onto the particles, providing numerous amino reaction sites. In the final step, an acylation reaction was initiated between stearoyl chloride and the amino groups to obtain the final product, designated as C_(18)-NH_(2)-GPTS-SiO_(2). Elemental analysis, FT-IR spectroscopy, Zeta potential analysis, thermogravimetric analysis(TGA), and scanning electron microscopy(SEM) were employed to investigate the success of the chemical modifications at each step. The carbon content increased from 0.55% to higher than 8.29%. Thus, it solved the low carbon loading capacity problem when modifying NPS microspheres with traditional C_(18) reversed phase(e. g., octadecyl chlorosilane modification). Meanwhile, the reasons for the considerable differences between NPS and porous silica(PS) microspheres in terms of the reactivity to surface modification were investigated in detail. The BET method was employed to compare the pore structures. FT-IR and ^(29)Si solid-state NMR spectroscopy were employed to analyze the differences in the structure and quantity of silanol groups on the surfaces of the NPS and PS microspheres. Differences were observed not only in the pore size and surface area, but also in the types of silanol groups. FT-IR analysis indicated that the NPS and PS microspheres had different υ_(Si-OH) band positions, which shifted from 955 to 975 cm^(-1), respectively. ^(29)Si solid-state NMR analysis further highlighted the differences in structural information for Si atom

关 键 词：加压毛细管电色谱 亚微米无孔二氧化硅微球 高碳含量 硅羟基 电渗流 

分 类 号：O658[理学—分析化学]