[Hydrogen-bonded organic frameworks： preparation and applications in separation and analysis]

This review provides a comprehensive and systematic overview of recent advances in the synthesis，functionalization and separation-related applications of hydrogen-bonded organic frameworks （HOFs） and their composite materials. HOFs represent an emerging and distinctive class of crystalline porous materials，constructed from organic building blocks via directional hydrogen bonding and other non-covalent interactions. They exhibit high crystallinity，tunable structures，mild synthesis conditions，ease of regeneration，and solution processability. Owing to these traits，particularly the designable pore environments and modifiable surfaces，HOFs hold great promise for advanced separation tasks that demand precise molecular recognition and efficient mass transfer. The first part of this paper reviews the main design strategies，synthetic methodologies and post-synthetic modification techniques of HOFs. The key preparation methods such as solvent evaporation，solvothermal synthesis and self-assembly，as well as advanced preparation methods such as in-situ growth on substrates，are introduced in detail. The review focuses on the important preparation parameters，underlying separation mechanisms and diverse applications of HOFs. Post-synthesis modification strategies including chemical grafting and functional group conversion have been particularly emphasized. These methods can adjust the properties of HOFs without compromising their structural integrity. This review also explores the mechanisms by which synthesis and improvement methods affect the structural stability，pore properties and functional performance of composite materials. The second part summarizes the various applications of HOF materials in the field of separation science over the past few years. In the application of chromatography solid-phase，the use of HOFs as a new type of stationary phase in gas chromatography and capillary electrochromatography was explored. Their excellent chromatographic separation ability is attributed to their pore structure，uniform pore size，and designable surface functional groups of HOFs. In terms of sample pretreatment，the applications of HOFs and their composites in dispersive solid-phase extraction，solid-phase microextraction and magnetic solid-phase extraction are elaborated. These application methods demonstrate high extraction efficiency，rapid adsorption kinetics and excellent reusability. The application of adsorption removal by HOFs has been comprehensively and deeply summarized. This includes the capture of heavy metal ions，the storage of radioactive nuclides，the recovery of volatile iodine and the removal of organic dyes. These reports indicate that HOFs possess high adsorption capacity，high selectivity and stability under extremely harsh conditions. In the review，it was found that HOFs possess inherent characteristics such as pre-designed framework structure，high specific surface area，modular functions and unique self-repairing properties. These properties determine their separation performance. This article clarifies the selectivity，adsorption capacity，kinetic properties and recyclability based on HOFs，highlighting the structure-function relationships. The above systematic analysis provides a methodological reference for designing HOFs to address targeted and challenging separations. In conclusion，because of their designable structures and mild synthesis methods，HOF materials demonstrate great potential for application in separation science. However，challenges such as long-term stability in harsh environments，large-scale production and anti-interference capabilities in real samples still exist. Future research should focus on developing more stable HOFs materials，integrating them into micro-devices and utilizing artificial intelligence-assisted design to accelerate practical applications in environmental protection and resource recovery.