Liu Jin, Wu Fan, Gan Lin, Jin Le-Yi, Lin Zi-An
Ministry of Education Key Laboratory of Analytical Science for Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, College of Chemistry, Fuzhou University, Fuzhou 350108, China.
Se Pu. 2023 Oct;41(10):843-852. doi: 10.3724/SP.J.1123.2023.04021.
Given continuous developments in industrial and scientific research, the separation and analysis of complex systems with high sensitivity, throughput, and selectivity is facing new challenges. Chromatography plays an irreplaceable role in separation science and is widely applied in environmental monitoring, pharmaceutical analysis, and food safety. Owing to their outstanding advantages, such as high loading capacity, precise quantification, and good reproducibility, chromatographic separation techniques based on various retention mechanisms have been utilized to detect different analytes. The stationary phase is the core material of chromatographic columns and has an extremely important influence on their separation performance. The selectivity and efficiency of separation largely depend on the chromatographic stationary phase. However, traditional stationary phases, such as silicon-based matrices, are characterized by complex preparation processes, poor permeability, large mass transfer resistance, and a narrow pH range. In addition, polymer matrices show poor mechanical stability and susceptibility to swelling, which limit their applications in the field of separation. Therefore, the development of novel stationary phases with the advantages of traditional stationary phases has become a research emphasis in the field of analytical science in efforts to meet separation requirements under different environments. Various stationary phases based on novel porous materials, such as metal organic frameworks (MOFs), porous organic cages (POCs), and covalent organic frameworks (COFs), are used for chromatographic separation. As mesh crystalline porous materials, MOFs have the advantages of a large surface area, adjustable structure, and easy functionalization; thus, they are widely used as chromatographic stationary phases in reverse-phase chromatography, hydrophilic-mode chromatography, mixed-mode chromatography, and other separation modes. However, because the pore size of MOFs is small and most MOFs demonstrate poor chemical stability under acidic or alkaline conditions, their applications in chromatographic separation are greatly limited. COFs are porous, crystalline polymer materials composed of light elements (H, O, C, N, B, and Si) connected via covalent bonds. Their advantages include a low density, large specific surface area, high porosity, good chemical and thermal stability, regular pores, and adjustable pore sizes. Because of their unique structures and properties, COFs are widely used in many fields such as catalysis, enrichment, gas capture, and sensing. COF materials are also suitable for separation analysis and considered ideal materials for novel chromatographic stationary phases. This review summarizes the latest research progress on the preparation and applications of COF-based chromatographic stationary phases over the past five years. First, the preparation of COF-based stationary phases (SiO@COFs stationary phase, COFs monolithic stationary phase, pure COFs stationary phase and COFs-coated stationary phase) is introduced. The latest applications of COF-based stationary phases in the separation of organic compounds, isomers, and chiral compounds are then described in detail. Finally, the future development trends and challenges of chromatographic stationary phases based on COFs are discussed to provide new ideas for the future design and development of novel chromatographic stationary phases based on COFs.
随着工业和科学研究的不断发展，对复杂系统进行高灵敏度、高通量和高选择性的分离与分析面临着新的挑战。色谱法在分离科学中发挥着不可替代的作用，广泛应用于环境监测、药物分析和食品安全等领域。基于各种保留机制的色谱分离技术因其具有高负载量、精确定量和良好重现性等突出优点，已被用于检测不同的分析物。固定相是色谱柱的核心材料，对其分离性能有着极其重要的影响。分离的选择性和效率在很大程度上取决于色谱固定相。然而，传统的固定相，如硅基基质，具有制备过程复杂、渗透率低、传质阻力大以及pH范围窄等特点。此外，聚合物基质表现出较差的机械稳定性和易溶胀性，这限制了它们在分离领域的应用。因此，开发具有传统固定相优点的新型固定相已成为分析科学领域的研究重点，以满足不同环境下的分离要求。各种基于新型多孔材料的固定相，如金属有机框架（MOF）、多孔有机笼（POC）和共价有机框架（COF），被用于色谱分离。作为网状结晶多孔材料，MOF具有比表面积大、结构可调节和易于功能化等优点；因此，它们被广泛用作反相色谱、亲水模式色谱、混合模式色谱和其他分离模式中的色谱固定相。然而，由于MOF的孔径较小，且大多数MOF在酸性或碱性条件下表现出较差的化学稳定性，它们在色谱分离中的应用受到很大限制。COF是由轻元素（H、O、C、N、B和Si）通过共价键连接而成的多孔结晶聚合物材料。它们的优点包括低密度、大比表面积高孔隙率、良好的化学和热稳定性、规则的孔结构以及可调节的孔径。由于其独特的结构和性能，COF被广泛应用于催化、富集、气体捕获和传感等许多领域。COF材料也适用于分离分析，被认为是新型色谱固定相的理想材料。本综述总结了过去五年中基于COF的色谱固定相的制备和应用的最新研究进展。首先，介绍了基于COF的固定相（SiO@COF固定相、COF整体固定相、纯COF固定相和COF涂层固定相）的制备。然后详细描述了基于COF的固定相在有机化合物、异构体和手性化合物分离中的最新应用。最后，讨论了基于COF的色谱固定相的未来发展趋势和挑战，为未来基于COF的新型色谱固定相的设计和开发提供新思路。
