Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Institute of Modern Separation Science, Key Laboratory of Modern Separation Science in Shaanxi Province, Northwest University, Xi'an 710069, China.
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Institute of Modern Separation Science, Key Laboratory of Modern Separation Science in Shaanxi Province, Northwest University, Xi'an 710069, China.
J Chromatogr A. 2022 Jul 19;1675:463165. doi: 10.1016/j.chroma.2022.463165. Epub 2022 May 20.
High-performance liquid chromatography (HPLC) is a powerful tool to separate and analyze complex samples. Monodiseperse porous silica microspheres (MPSMs) have been widely used as column packings in HPLC. However, synthesis of MPSMs with controllable sizes of both particles and pores for the separation of small solutes and proteins in HPLC still remains a challenge. In this paper, an effective and facile approach to prepare MPSMs with controllable particle size and pore size by using porous polymer microspheres as templates is presented. By employing porous P microspheres as templates and tetraethyl orthosilicate (TEOS) as the silica source, 5 μm MPSMs with tunable pore sizes were synthesized successfully. The as-prepared MPSMs were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), dynamic laser scattering, and mercury intrusion porosimetry. The results indicated that the MPSMs obtained retained the original size of the polymer templating particles and calcination caused almost no shrinkage. Furthermore, the effects of the pore size of polymer template microspheres, different amino-functionalizations of P microspheres and the mass ratio of P microspheres/TEOS on the pore size of MPSMs were carefully studied. The results indicated that the pore size of MPSMs was adjusted from 20 to 69 nm by controlling the pore size of the polymer microspheres and the mass ratio of P microspheres/TEOS in the sol-gel process. In addition, the amino-functionalization of P microspheres with different structure-directing agents, such as (3-aminopropyl)triethoxysilane (APTES), trimethylamine hydrochloride (TMA) and tetraethylenepentamine (TEPA), also resulted in MPSMs with the different pore sizes. MPSMs with large pore sizes of more than 30 nm were fabricated by using TEPA-functionalized P microspheres as templates, while with TMA-functionalized P microspheres as templates, MPSMs with pore sizes of approximately 10 nm were obtained. The as-prepared MPSMs were further modified with different silanes, such as C4, C8 and C18, to explore as stationary phases for the separation of proteins and small solutes in reversed phase liquidi chromatography (RPLC). The results illustrated that the baseline separation of 7 kinds of proteins could be achieved based on MPSMs with pore sizes of 30 nm, and 6 kinds of alkyl benzenes and 5 kinds of aromatic alcohol homologs could be separated completely based on MPSMs with pore sizes of 11 nm. This work demonstrated that MPSMs prepared by applying the polymer templating method showed a promising potential applicability in HPLC.
高效液相色谱（HPLC）是一种分离和分析复杂样品的强大工具。单分散多孔硅胶微球（MPSMs）已广泛用作 HPLC 中的柱填料。然而，对于分离 HPLC 中小溶质和蛋白质，仍然需要合成具有可控粒径和孔径的 MPSMs。本文提出了一种通过使用多孔聚合物微球作为模板制备具有可控粒径和孔径的 MPSMs 的有效且简便的方法。以多孔 P 微球为模板，正硅酸乙酯（TEOS）为硅源，成功合成了可调节孔径的 5μm MPSMs。通过扫描电子显微镜（SEM）、傅里叶变换红外（FT-IR）光谱、热重分析（TGA）、动态激光散射和压汞法对所制备的 MPSMs 进行了表征。结果表明，MPSMs 保留了聚合物模板粒子的原始尺寸，并且煅烧几乎没有收缩。此外，还仔细研究了聚合物模板微球的孔径、P 微球的不同氨基功能化以及 P 微球/TEOS 质量比对 MPSMs 孔径的影响。结果表明，通过控制聚合物微球的孔径和溶胶-凝胶过程中 P 微球/TEOS 的质量比，可以将 MPSMs 的孔径从 20nm 调节到 69nm。此外，具有不同结构导向剂的 P 微球的氨基功能化，如（3-氨丙基）三乙氧基硅烷（APTES）、盐酸三甲胺（TMA）和四乙烯五胺（TEPA），也导致了具有不同孔径的 MPSMs。使用 TEPA 功能化的 P 微球作为模板制备了具有大孔径（大于 30nm）的 MPSMs，而使用 TMA 功能化的 P 微球作为模板则制备了孔径约为 10nm 的 MPSMs。进一步用不同的硅烷，如 C4、C8 和 C18，对所制备的 MPSMs 进行修饰，以探索其作为反相液相色谱（RPLC）中分离蛋白质和小溶质的固定相。结果表明，基于孔径为 30nm 的 MPSMs 可以实现 7 种蛋白质的基线分离，而基于孔径为 11nm 的 MPSMs 可以完全分离 6 种烷基苯和 5 种芳香醇同系物。这项工作表明，通过应用聚合物模板法制备的 MPSMs 在 HPLC 中具有潜在的应用前景。
