Facile fabrication of hydroxyl-functionalized hypercrosslinked polymer for sensitive determination of chlorophenols

Recent advances in synthesis and applications of hyper-crosslinked porous organic polymers for sample pretreatment: A review

Hyper-crosslinked porous organic polymers (HCPs) are nanoporous materials synthesized through Friedel-Crafts reactions, which covalently crosslink monomeric units to integrate the high porosity, large surface area, and tunable pore architecture of porous networks with the structural diversity, lightweight nature, and compositional flexibility inherent to polymeric systems. These materials exhibit excellent thermal/chemical stability, facile surface functionalization, and scalable synthesis protocols, enabling versatile applications in drug delivery, chromatography, catalysis, and gas storage. In recent years, HCPs have gained prominence as advanced sorbents in sample pretreatment, owing to their inherent physicochemical characteristics that align closely with the critical requirements for high-performance extraction or purification adsorbents. This review aims to present recent advancements in HCPs preparation, with a primary focus on their applications in analytical sample preparation. A systematic investigation of HCP-based adsorption mechanisms, structural design principles, and fabrication methodologies was conducted to establish robust structure-function correlations through performance evaluation across diverse extraction techniques, including column solid-phase extraction (SPE), magnetic SPE (MSPE), solid-phase microextraction (SPME), and other miniaturized SPE formats, for the pre-concentration of target analytes in food, environmental, and biological samples. Finally, we delineate current challenges and future research directions, proposing innovative engineering strategies to advance HCPs for addressing complex analytical matrix challenges.

Membrane protected multi-template molecularly imprinted polymer based micro-solid phase extraction coupled with high performance liquid chromatography for analysis of chlorophenols

Multi-template molecularly imprinted materials (mt-MIPs) were prepared by surface imprinting and sealed into porous nylon membrane as micro-solid phase extraction (μ-SPE) device, coupled with high performance liquid chromatography (HPLC) to simultaneously extract and determine five typical chlorophenols (CPs) in leather matrices. By using well-prepared mesoporous silica modified multiwalled carbon nanotubes (MWCNTs@mSi) as supporting materials, and the mixture solution of five CPs as templates, the imprinted layer containing recognition sites of the CPs were formed via free radical polymerization. The as-prepared mt-MIPs were characterized by SEM, TEM, FT-IR and TGA, and the adsorption properties were investigated including static, dynamic and selective adsorption, showing high adsorption capacity of 39.15‒71.43 mg g-1 and rapid mass transfer rate (within 30 min). Parameters affecting the extraction efficiency of membrane protected μ-SPE were optimized, including the type of membrane, amount of adsorbent, type and volume of desorption solvent, desorption time and salt effect. The established mt-MIPs-μ-SPE-HPLC method demonstrated satisfactory linearity of 2.0‒200 µg L-1, high sensitivity with LODs of 0.17‒0.52 µg L-1, and high enrichment factor (70.6‒144). Consequently, the method was successfully applied to the analysis of five CPs in tannery wastewater, finished leather and wet blue samples. Spike recoveries ranged from 73.00 %‒115.2 %, with RSDs of 0.28 %‒11.4 %, and matrix interference was examined to be negligible. The developed method proved viable for the simultaneous extraction and quantification of trace CPs in complex leather matrices.

Construction of novel hyper-crosslinked polymers with adjustable hydrophilicity for efficient extraction of nitroimidazoles

To effectively control food safety risks caused by nitroimidazoles (NDZs), a sensitive detection method was established on the basis of a newly-developed solid-phase extraction (SPE) sorbent named as Phl-TBM that is a porous polymer prepared by crosslinking natural phloretin with (2,4,6-tris(bromomethyl)mesitylene. The Phl-TBM presented outstanding NDZs adsorption capacity, which can be ascribed to its well-developed porosity and multiple hydrogen bonding sites. With Phl-TBM as SPE sorbent, NDZs were successfully isolated and enriched from lake water, Basa fish, and beef before being assayed by high-performance liquid chromatography-diode array detector. This Phl-TBM based method has a detection limit of 0.02-0.06 ng mL-1 in lake water, 0.60-1.50 ng g-1 in Basa fish, and 0.70-1.20 ng g-1 in beef. The method recoveries are 80.0-120 % with relative standard deviations less than 8.1 %. This study presents an effective and feasible approach for detection of NDZs residues at trace level.

Fabrication of chitin based hydrophilic hyper-crosslinked porous polymer for efficiently removing bisphenol A from water

Water pollution caused by bisphenol A (BPA) has become the world problem. Designing and preparing cost-effective and biodegradable sorbents for the effectively adsorptive removal of bisphenol A from wastewater is of immense significance. Herein, a natural polysaccharide (chitin) was used as raw materials to be grafted with styrene (GS), then crosslinked with α,α'-dichloro-p-xylene (DCX) to form the hyper-crosslinked polymer (labeled as CGS@DCX). The CGS@DCX showed high adsorptive affinity for bisphenol A, with adsorption capacity of 441 mg g-1. Various studies gave an insight into the adsorption process, demonstrating that the highly efficient adsorption of BPA by the CGS@DCX is mainly based on the π-π stacking, hydrogen-bond interaction, polar interaction and pore adsorption. Moreover, the CGS@DCX had high chemical stability, good reusability (9 cycles) and fast adsorption kinetics (10 min) for adsorption of BPA. This work provides a promising strategy for the design and synthesis of novel yet eco-friendly sorbents to solve environmental problems.

One-step preparation of carboxyl-functionalized porous organic polymer as sorbent for enrichment of phenols in bottled water, juice and honey samples

Herein, a novel carboxyl-functionalized porous organic polymer (COOH-POP) was prepared as sorbent. Due to multiple hydrogen bonds and π-π interactions between COOH-POP and phenols, COOH-POP shows good enrichment ability and very fast adsorption rate for phenols. Then, an analytical method was developed for determination of five phenols (2-chlorophenol, bisphenol A, 2,6-dichlorophenol, 2,4-dichlorophenol and p-tert-butylphenol) in bottled water, lemon juice, peach juice and honey samples using COOH-POP as solid phase extraction sorbent in combination with high performance liquid chromatography. Under optimal conditions, the COOH-POP based method gave the detection limits (S/N = 3) of 0.02-0.10 ng mL-1 for bottled water, 0.03-0.12 ng mL-1 for lemon juice, 0.03-0.25 ng mL-1 for peach juice and 0.7-1.5 ng g-1 for honey samples. The recoveries for spiked samples ranged from 84.0 % to 119.0 % with relative standard deviation less than 7.6 %. This study provides a new yet effective method for enrichment of phenols by designing carboxyl-functionalized porous organic polymer as sorbent.

Synthesis of phosphate-functionalized magnetic porous organic polymer: A sorbent for sensitive determination of neonicotinoid insecticides in water and lemon juice

There is an urgent need to prepare advanced functional materials for extraction and enrichment of trace organic pollutants from different samples. In this work, two novel phosphate-functionalized porous organic polymers (DBP-POP and DPP-POP) were synthesized for the first time. Compared with phosphate-free counterpart, both phosphate-functionalized POPs showed excellent adsorption performance for the neonicotinoids due to the hydrogen bonding, π-π interaction and hydrophobic interaction. For ease of separating the sorbent from solution, magnetic DBP-POP (M-DBP-POP) was further prepared as sorbent to extract neonicotinoids from environmental water and lemon juice samples prior to their determination by high performance liquid chromatography-ultraviolet detection. Under optimal conditions, the detection limits (S/N = 3) of the method were 0.01-0.08 ng mL-1 for water and 0.03-0.10 ng mL-1 for lemon juice. The recoveries were in the range of 80.0% to 113.0% with relative standard deviation less than 10.6%. This work demonstrated the feasibility of phosphate-functionalized POPs for adsorption applications.