Metal-organic frameworks (MOFs) are a class of porous crystalline materials composed of metal centers or clusters assembled with organic ligands. These materials possess excellent properties, such as large surface areas, high porosities, uniform pore sizes, and diverse structures. Thus, MOFs have been widely applied in various fields, including catalysis, adsorption, sensing, sample pretreatment, and chromatographic separation. The applications of MOFs as stationary phases for chromatographic separation and analysis have attracted considerable attention from the research community in recent years. Compared with traditional chromatographic stationary phases, such as mesoporous silica, nanoparticles, and porous layers, MOFs possess flexible and tunable pore sizes and structures, thereby enabling precise control over their intermolecular interactions. Furthermore, the wide range of functional ligands and topologies of MOFs could potentially facilitate the separation and analysis of complex samples. These unique advantages render MOFs highly suitable for constructing novel chromatographic stationary phases.This article focuses primarily on the construction methods of MOFs as chromatographic stationary phases, and provides an overview of the latest research advancements in their applications in several chromatographic separation techniques such as high performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrochromatography (CEC). The existing methods for the preparation and construction of MOFs-based chromatographic stationary phases are classified and evaluated. The construction methods for MOFs as stationary phases for HPLC mainly include filling, precursor-doped polymerization, and post-modification. The construction methods for MOFs as stationary phases for GC predominantly include in situ growth, static coating, and dynamic coating. The stationary phases for CEC can be categorized into packed columns, monolithic columns, and open-tubular columns. Compared with monolithic and packed columns, open-tubular CEC (OT-CEC) offers numerous advantages, including a more flexible and convenient preparation method, enhanced compatibility with various separation media, and higher separation efficiency. Consequently, OT-CEC has emerged as an important method for investigating the preparation of stationary phases for CEC. Several methods such as physical adsorption, covalent attachment, and electrostatic interactions have been developed for the preparation and modification of MOFs-based CEC stationary phases, and extensive studies have been conducted to optimize the performance and applications of MOFs in OT-CEC. However, the existing methods for constructing MOFs-based chromatographic stationary phases present certain limitations. Therefore, the selection of the appropriate MOFs, optimization of their preparation methods, and examination of their performance in different separation modes have become the focus of intensive research.This review also summarizes the different analytical targets (e. g., chiral small molecules, biomacromolecules, and nonchiral molecules) and corresponding separation effects achieved using various MOFs-based chromatographic stationary phases. Finally, future studies focusing on the development of MOFs as chromatographic separation media are discussed. Overall, this review provides a valuable reference for the rational construction and practical applications of advanced MOFs-based chromatographic stationary phases.
金属有机骨架(MOFs)是由金属中心或团簇与有机配体组装而成的一类新型晶体多孔材料,具有比表面积大、孔隙率高、孔径均匀以及结构多样等优良特性,已被广泛应用于催化、吸附、传感、样品前处理以及色谱分离等领域。近年来MOFs在色谱分离领域的应用备受关注。与传统色谱固定相材料(如介孔二氧化硅、纳米粒子以及多孔层等)相比,MOFs具备灵活可调控的孔道尺寸和结构,能够实现对分子间相互作用的精确控制。此外,种类丰富多样的功能配体和拓扑结构拓宽了MOFs在分离领域的应用范围,有望实现更多类型复杂样品的分离分析。MOFs的这些独特优势使其非常适用于构建各类新型色谱固定相。迄今为止MOFs色谱固定相已展现出优异的分离效能,在色谱分离领域具有明显的优势和巨大的应用潜力。本文重点介绍了MOFs色谱固定相的构建方法及其在色谱分离应用中的最新研究进展,包括高效液相色谱(HPLC)、气相色谱(GC)以及毛细管电色谱(CEC)领域;针对现有的MOFs色谱固定相制备方法进行了归类总结,并简要探讨了各个方法的优缺点及发展方向;还总结了近年来MOFs色谱固定相的典型应用;最后,本文对MOFs色谱分离介质未来的研究重点及发展前景进行了展望,以期为先进MOFs色谱固定相的理性构建与应用提供参考。
Keywords: chromatographic stationary phase; metal-organic frameworks (MOFs); review; separation.