A miniaturized sorbent phase-based extraction device in the form of syringe filter holder using molecularly imprinted polymer as sorbent and its application to extract benzophenones

Facile synthesis of hierarchically flower-like hollow covalent organic frameworks for enrichment and metabolic analysis of benzophenone derivatives in mouse serum

Benzophenone derivatives (BPs), as synthetic chemicals widely used in personal care products, have drawn increasing attention due to their potential health risks. However, monitoring BPs in biological samples remains challenging due to their complex matrices and the deficiency in sensitivity and selectivity in current methods. Herein, a method combining hierarchically flower-like hollow covalent organic frameworks (HFH-COFs) with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for the enrichment and detection of BPs in serum samples. The HFH-COFs were synthesized at room temperature and employed as an adsorbent due to their advantageous properties. The as-prepared HFH-COFs exhibited high specific surface area (2286.53 m²/g), excellent chemical stability, and good thermal stability, making them ideal for efficient enrichment applications. Under optimized experimental conditions, five BPs were effectively enriched and quantified by HPLC-MS/MS in the range of 50.0-5000.0 ng/L with good linearity (r > 0.9992). The limit of detections was 0.5-10.0 ng/L. Furthermore, HFH-COFs showed high enrichment factors even over multiple adsorption-desorption cycles. This study proposed a reliable and efficient method for monitoring endocrine-disrupting compounds in complex biological samples and highlighted the potential of HFH-COFs as a superior adsorbent material for BP.

The environmental sources of benzophenones: Distribution, pretreatment, analysis and removal techniques

Benzophenones (BPs) have wide practical applications in real human life due to its presence in personal care products, UV-filters, drugs, food packaging bags, etc. It enters the wastewater by daily routine activities such as showering, impacting the whole aquatic system, then posing a threat to human health. Due to this fact, the monitoring and removal of BPs in the environment is quite important. In the past decade, various novel analytical and removal techniques have been developed for the determination of BPs in environmental samples including wastewater, municipal landfill leachate, sewage sludge, and aquatic plants. This review provides a critical summary and comparison of the available cutting-edge pretreatment, determination and removal techniques of BPs in environment. It also focuses on novel materials and techniques in keeping with the concept of "green chemistry", and describes on challenges associated with the analysis of BPs, removal technologies, suggesting future development strategies.

Benzophenones in the Environment: Occurrence, Fate and Sample Preparation in the Analysis

The ubiquitous presence of emerging contaminants in the environment is an issue of great concern. Notably, for some of them, no established regulation exists. Benzophenones are listed as emerging contaminants, which have been identified in the environment as well as in human fluids, such as urine, placenta, and breast milk. Their accumulation and stability in the environment, combined with the revealed adverse effects on ecosystems including endocrine, reproductive, and other disorders, have triggered significant interest for research. Benzophenones should be extracted from environmental samples and determined for environmental-monitoring purposes to assess their presence and possible dangers. Numerous sample preparation methods for benzophenones in environmental matrices and industrial effluents have been proposed and their detection in more complex matrices, such as fish and sludges, has also been reported. These methods range from classical to more state-of-the-art methods, such as solid-phase extraction, dispersive SPE, LLE, SBSE, etc., and the analysis is mostly completed with liquid chromatography, using several detection modes. This review critically outlines sample preparation methods that have been proposed to date, for the extraction of benzophenones from simple and complex environmental matrices and for cleaning up sample extracts to eliminate potential interfering components that coexist therein. Moreover, it provides a brief overview of their occurrence, fate, and toxicity.

Recent Advances in the Application of Covalent Organic Frameworks in Extraction: A Review

Covalent organic frameworks (COFs) are a class of emerging materials that are synthesized based on the covalent bonds between different building blocks. COFs possess unique attributes in terms of high porosity, tunable structure, ordered channels, easy modification, large surface area, and great physical and chemical stability. Due to these features, COFs have been extensively applied as adsorbents in various extraction modes. Enhanced extraction performance could be reached with modified COFs, where COFs are presented as composites with other materials including nanomaterials, carbon and its derivatives, silica, metal-organic frameworks, molecularly imprinted polymers, etc. This review article describes the recent advances, developments, and applications of COF-based materials being utilized as adsorbents in the extraction methods. The COFs, their properties, their synthesis approaches as well as their composite structures are reviewed. Most importantly, suggested mechanisms for the extraction of analyte(s) by COF-based materials are also discussed. Finally, the current challenges and future prospects of COF-based materials in extraction methods are summarized and considered in order to provide more insights into this field.

Covalent organic framework-V modified porous polypropylene hollow fiber with detachable dumbbell-shaped structure for stir bar sorptive extraction of benzophenones

Polypropylene hollow fiber is a kind of ideal material for stir bar sorptive extraction (SBSE) which possesses the advantages of porous structure, large specific surface area, high mechanical strength, and good solvent resistance. In this work, a novel SBSE device using the polypropylene hollow fiber-based stir bar with the detachable dumbbell-shaped structure was designed and prepared. Covalent organic framework-V (COF-V), which possesses porous structure, sphere shape with large specific surface area, was synthesized at room temperature and grown on polypropylene hollow fiber by polydopamine modification method. Compared with previous studies which used etched poly(ether ether ketone) as supporting material, polypropylene hollow fiber omitted the complicated, difficult and dangerous pretreatment process with high concentrated sulfuric acid. The immobilization of COF-V on the polypropylene hollow fiber significantly endows them with multiple interaction abilities including hydrophobic interaction and π-π interaction. The stir bar showed good performance and stability for the extraction of four benzophenones including BP-1, BP-6, BP-3 and Ph-BP. By coupling with HPLC-UV, the COF-V@polypropylene hollow fiber based SBSE method showed wide linear range (0.1-200 ng/mL), excellent linearity (R² ≥ 0.9979), high sensitivity (LODs in the range of 0.02-0.03 ng/mL), and good repeatability (RSD ≤ 5.21%). This method was successfully applied to the analysis of benzophenones in soil and sunscreen samples.

Hollow tube covalent organic framework for syringe filter-based extraction of ultraviolet stabilizer in food contact materials

In this work, a novel hollow tube covalent organic framework constructed by cyclotricatechylene and tetrafluoroterephthalonitrile (CTC-TFPN-COF) with polyether bond was synthesized, and it was coated on filter membrane for extraction of ultraviolet stabilizer in migration from food contact materials. Since the monomers of the polymer were linked by polyether bond, the CTC-TFPN-COF exhibited strong chemical stability in severe conditions such as acid, alkali and various organic solvent. The excellent features of high porosity and robust structure endowed the CTC-TFPN-COF good candidate as adsorbent for extraction of ultraviolet stabilizer. Moreover, the CTC-TFPN-COF coated membranes were immobilized on syringe filter and coupled with multiple channel injection pump to realize high throughput sample pretreatment strategy. Subsequently, a sensitive analytical method for ultraviolet stabilizer was established followed by ultra-high performance liquid chromatography-tandem mass spectrometry. The flow rate of extraction and desorption, elution solvent and the volume of desorption solvent were optimized. The method was assessed, which showed wide linear ranges with R2 greater than 0.99, low limits of detection (0.9-91 ng L^-1) and low limits of quantification (3-300 ng L^-1). The developed method was successfully applied to determine trace ultraviolet stabilizer in the migration of food contact materials with different simulated solution, which demonstrated its promising potential in practical analysis.

Hierarchically porous poly(ethylenimine) modified poly(styrene-co-divinylbenzene) microspheres for the adsorption of gold nanoparticles and simultaneously being transformed as the nanoparticles immobilized catalyst

With the extensive applications of gold nanoparticles (AuNPs) and the confirmation of their toxicity on human health and environment, it was urgent to remove AuNPs from environment. The hierarchically porous poly(ethylenimine) modified poly(styrene-co-divinylbenzene) microsphere (PEI-PS-DVB) was prepared and characterized by scanning electron microscopy, X-ray diffraction, transform infrared spectrometry, energy dispersive X-ray spectrometry, elemental analysis, contact angle, zeta potential analysis, N₂ adsorption-desorption and mercury intrusion porosimetry. PEI-PS-DVB possessed abundant flow-through pores (70-120 nm) and meso/micropores (<50 nm); the former pores enabled full availability of the adsorbent to relatively large adsorbate, i.e. AuNPs, with fast mass transfer, while the latter ones ensured large surface area for high adsorption capacity. Thanks to its plentiful nitrogen and special hierarchical pores, PEI-PS-DVB was suitable for the adsorption of AuNPs by electrostatic interaction and special affinity between nitrogen and Au. The adsorption obeyed the pseudo-first-order kinetic and Langmuir isotherm models. The maximum adsorption capacity based on Langmuir model was 806.5 mg/g. Moreover, PEI-PS-DVB adsorbing AuNPs could be the efficient catalyst for the reduction of 4-nitrophenol with satisfactory reusability. The developed hierarchically porous PEI-PS-DVB was a promising adsorbent for AuNPs with high adsorption capacity, and recycling usage of waste AuNPs conformed to the green and sustainable concept.

Current trends on microextraction by packed sorbent – fundamentals, application fields, innovative improvements and future applications

MEPS, the acronym of microextraction by packed sorbent, is a simple, fast and user- and environmentally-friendly miniaturization of the popular solid-phase extraction technique (SPE).

Molecularly imprinted solid phase extraction coupled with gas chromatography-mass spectrometry for determination of N-Nitrosodiphenylamine in water samples

In this study, the molecularly imprinted polymers (MIPs) with high specific surface area and extraction efficiency of N-Nitrosodiphenylamine (NDPhA) were successfully prepared and a highly sensitive and selective method was developed for determination of NDPhA in water samples using MIPs solid-phase extraction (SPE) coupled with gas chromatography mass spectrometry (GC-MS) detection. The MIPs were successfully prepared using the method of precipitation polymerization and using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, and N, N-Diphenylformamide as the template molecule. The newly synthesized MIPs were characterized and used as SPE sorbents. Under the optimized conditions, the average recoveries of NDPhA spiked in ultrapure water were higher than 94% ± 2.9% at three different concentrations and the limit of detection and limit of quantitation were 0.8 ng L^-1 and 2.4 ng L^-1, respectively. Moreover, the high selectivity of MIPs was attained and the satisfactory recoveries of NDPhA which were spiked in to real samples were achieved in the range of 92-107% with relative standard deviations (RSDs) within 0.3-7.9%. The low levels of NDPhA were detected in the two of twelve wastewater samples with concentrations of 5.6 ng L^-1 and 3.6 ng L^-1 with RSDs of 5.6% and 2.8%, respectively. The developed MIP-SPE method was proved to be practically feasible for selective extraction and enrichment of NDPhA in real water samples.