Authors: J. Huang | Jingyi Yan | Qin Ji | Lingxin Chen | Jinhua Li
Source: Chinese Journal of Chromatography (article, 2025-07-30)
Field: Chemistry — Analytical Chemistry

Applications of metal/covalent-organic framework compositing molecularly imprinted materials-based solid-phase extraction combined with chromatography and mass spectrometry for screening and recognition of new pollutants in coastal zone The coastal zone， a critical ecotone where marine and terrestrial environments converge， contains complex ecosystems， is subjected to highly intense human activity， and is experiencing escalating threats from anthropogenic pollutants. Rapid industrial and urban development has witnessed the continual entry of new pollutants（NPs）， such as persistent organic pollutants（POPs）， endocrine-disrupting chemicals（EDCs）， antibiotics， and microplastics， into coastal zones. These NPs are present in low concentrations in the environment， are structurally diverse and chemically complex， and pose severe risks to biodiversity and human health. Methods for effectively screening， recognizing， and precisely determining NPs are urgently required to understand their environmental fate and toxicological impact， and to formulate abatement-control strategies. However， the intrinsic complexities of coastal matrices， as characterized by heterogeneous media（such as water， sediments， soil， biological components， and the atmosphere）， high salinity， and interference from a variety of species， demands advanced sample-pretreatment methodologies coupled with highly sensitive chromatography or chromatography-mass spectrometry（MS） techniques. Functional-material-based solid-phase extraction（SPE） has become an important sample-pretreatment method. Molecularly imprinted polymers（MIPs） that operate through “lock-and-key” molecular recognition， have become very popular in the SPE space. Nevertheless， MIPs suffer from issues such as template-molecule residues and/or leakage， low adsorption capacities， low mass-transfer rates， and poor complex-substrate adaptabilities， which restrict their practical applications. Recent years have seen the introduction of metal/covalent-organic framework（MOF/COF） materials with high specific surface areas and adjustable pore sizes that have provided new avenues for improving MIP performance in a manner that significantly enhances adsorption capacity， the mass-transfer rate， and applicability. Consequently， MOF/COF-MIP composite materials are attracting increasing levels of attention because SPE adsorbents play important roles when screening and identifying NPs in coastal zones. Herein， we review recent advances in MOF/COF-MIP composite materials for use in SPE-pretreatment applications prior to chromatography or chromatography-MS for the screening and identification of NPs in coastal zones. Firstly， MIP synthesis methods are briefly summarized， and key factors， such as adsorption capacity， the binding kinetics mass-transfer rate， selectivity， and anti-interference ability， are discussed in detail. Adsorption capacity depends on recognition-site density and accessibility， which can be optimized through controlled polymerization and MOF/COF-MIP hybridization. The mass-transfer rate， which is influenced by surface hydrophilicity/hydrophobicity and pore architecture， dictates the analyte-diffusion rate to the binding sites. Advanced imprinting strategies， such as those involving restricted access materials（RAMs） and multi-template imprinting， are critical for minimizing nonspecific interactions in complex matrices. Imprinting and selectivity factors（IFs and SFs， respectively）， as key indicators， need to be rationally provided to deliver MIPs that are highly and reliably selective. In addition， this paper discusses methods used to prepare MOF-MIP and COF-MIP composites， focusing on the structural advantages of MOFs and COFs， including designability. MOF/COF-MIP syntheses leverage structural and functional synergies between the framework and the MIP. MOFs， with their metallo-organic coordination networks， serve as stable substrates for surface imprinting， whereas COFs， which contain covalent linkages， enable functional groups to be precisely tailored. Techniques such as radical polymerization and sol-gel processes are employed to balance crosslinking density and structural integrity. Room-temperature and microemulsion polymerization strategies enhance sensitive-template compatibility， thereby preserving recognition-site fidelity. Emerging methodologies include magnetic composite fabrication， streamlined separation processes， and improved operational efficiencies in field applications. MOF/COF-MIP-SPE coupled with CMS， which is typically used to detect coastal NPs， including POPs， antibiotics， EDCs， and microplastics， is summarized. These composites are highly proficient in isolating trace-level NPs from heterogeneous matrices by leveraging their tailored porosities and selective binding abilities. Enhanced chemical stability ensures consistent performance under fluctuating pH and high ionic-strength conditions， whereas the hierarchical pore structure facilitates rapid analyte transport. These molecularly imprinted SPE-based（MISPE-based） composites deliver detection sensitivities that surpass those of conventional SPE coupled with chromatography or chromatography-MS， which underscores their significant potential for efficiently enriching and purifying NPs in complicated coastal media. In addition， we discuss possible challenges faced when analyzing NPs in coastal samples using MOF/COF-MIP composite-based SPE， including regeneration-efficiency limitations， long-term stability under harsh conditions， and synthesis-protocol scalability. Repeated use in dynamic coastal environments often leads to pore fouling or MIP-layer degradation， necessitating durable composite design innovation. Looking forward， we discuss future prospects for the synthesis and application of composites， emphasizing the keen pursuit of multifunctional MOF/COF-MIP composites that are capable of simultaneously adsorbing， recognizing， enriching， and catalytically degrading NPs. Interdisciplinary approaches， especially ones that use artificial intelligence to energize and sustainably develop， including machine-learning-guided material design， while abiding by green-chemistry principles， have been proposed to accelerate the development of next-generation composites. Computational models capable of predicting framework-pollutant interactions can streamline the creation of new composites， while sustainable synthesis routes， such as those that employ aqueous solvents and biodegradable components， are expected to minimize environmental impacts. In conclusion， this review aims to bridge the gap between fundamental research and the practical applications of MOF/COF-MIPs for detecting NPs. By addressing current limitations through multidisciplinary collaboration and sustainable engineering， these materials are expected to be highly efficient， economical， environmentally friendly， portable， and industrializable； combined with SPE followed by chromatography or chromatography-MS， they hold significant potential for the screening and identification of NPs in coastal zones. Chemistry ; Solid phase extraction ; Chromatography ; Mass spectrometry ; Pollutant ; Extraction (chemistry) ; Molecularly imprinted polymer ; Environmental chemistry ; Organic chemistry ; Selectivity ; Catalysis Analytical chemistry methods development ; Adsorption and biosorption for pollutant removal ; Water Quality Monitoring and Analysis