Strategic preparation of porous magnetic molecularly imprinted polymers via a simple and green method for high-performance adsorption and removal of meropenem

Preparation of protein-resistant magnetic molecularly imprinted polymers as solid-phase extraction adsorbents via a one-stone-two-birds strategy for selective enrichment of tetracycline in milk

The widespread presence of antibiotic residues in animal-derived foods poses serious risks to public health and the environment, emphasizing the need for urgent action. This study presented a novel lightweight, popcorn-like magnetic molecularly imprinted polymer (LPR-MMIPs) with protein-resistant properties, for the selective enrichment of tetracycline (TC) antibiotics in milk. During the preparation of LPR-MMIPs, bovine serum albumin (BSA) was used as the functional monomer, and tris(2-carboxyethyl)phosphine (TCEP) served as the reducing agent. Using a "one-stone-two-birds" strategy, TCEP not only converted the α-helical structure of BSA to a β-folded conformation for imprinting on the Fe3O4 carrier, but also etched the Fe3O4 into a lightweight, popcorn-like structure under acidic conditions. The BSA imprinting layer excludes proteins through electrostatic repulsion, and the reduced amount of carrier material significantly enhances the adsorption efficiency (Q = 12.7 mg g-1), selectivity (IF = 3.02, SC > 1.53), and reusability. Meanwhile, LPR-MMIPs, as solid-phase extraction adsorbents, have been successfully applied to the specific adsorption and separation of TC in real milk samples. The established method exhibits good accuracy, precision, and sensitivity, as evidenced by the low LOD (1.80 ng mL-1) and LOQ (5.60 ng mL-1), low RSDs (≤5.4 %), and high recovery rates (≥94.5 %). Besides, the method demonstrates excellent practical applicability for milk, offering a novel strategy for the selective enrichment of trace antibiotics in milk.

Extraction of short-chain fatty acid ethyl Ester in Baijiu using covalent organic framework-based magnetic nanoparticles: Theoretical screening and experimental validation

Short-chain fatty acid ethyl esters (SFAEEs) are critical aroma compounds in Baijiu, and their wider concentration range can lead to differences in the quality grade of Baijiu. Efficiently designing an SFAEEs adsorbent before instrument analysis remains challenging. In this work, nine functionalized covalent organic frameworks (COFs) with different postmodification groups were designed for targeting SFAEEs. Based on interaction energy as the evaluation criterion, COFs modified with 5-Mercapto-1-methyltetrazole (MMTZ) had been identified through density functional theory screening. Using imine COFs and MMTZ, novel magnetic nanoparticles (Fe3O4@COFs@MMTZ) were prepared and used to develop the magnetic solid-phase extraction of SFAEEs from Baijiu. The adsorption mechanism of Fe3O4@COFs@MMTZ was analyzed using wave function analysis, revealing that adsorption occurred via vdW interaction, CH···π interaction, and hydrogen bonding. This study provides a new concept for the rapid detection of SFAEEs and theoretical support for the scientific construction of quality control during Baijiu production.

Preparation strategy of molecularly imprinted polymers adsorbent based on multifunctional carrier for precise identification and enrichment of fenthion

Due to the existence of organophosphorus pesticides (OPs) in the environment and their potential hazards to ecosystems and human health, this study aimed to develop a novel adsorbent of OPs using multifunctional carriers and surface molecular imprinting technology (SMIT). SiO2-COOH served as a carrier, and molecularly imprinted polymers (MIPs) constituted a shell, creating a core-shell structured adsorbent. SMIT facilitated rapid and efficient binding between the target molecules and the imprinted cavities. The multifunctional SiO2-COOH enhanced the adsorbent's adsorption capacity, improved its mechanical stability, and strengthened the binding with the MIPs. The adsorbent demonstrated excellent specificity and reusability, achieving an adsorption capacity of 54.4 mg/g and the imprinting factor of 2.94. The relative recovery rate in actual sample detection ranged from 95.1% to 108.7%. This study provides a simple and effective method for detecting hazardous factors in environment protection and food safety fields, with significant scientific value and practical application potential.

A review on molecularly imprinted magnetic solid phase extraction emphasizing the analysis of antibiotics in complex matrices:Design, preparation, and application

Magnetic solid phase extraction (MSPE) has been widely employed in the isolation and enrichment of antibiotics in complex matrices because it presents various unique advantages over traditional SPE including simple operation, fast extraction procedure, low cost and eco-friendliness. In recently years, magnetic molecularly imprinted nanoparticles (MMINs) containing highly specific recognition performance have been widely used to specific extraction of antibiotics under the format of MSPE. In this connection, recent advances of MMINs in the analysis of antibiotic residues are reviewed. Firstly, the common structure of MMINs including core-shell, core-satellite, cavity structure and nanotube/nanosheet-supported structurewere introduced. After that, a main section covers the synthesis strategies of MMINs including one-step preparation and multi-steps preparation (precipitation polymerization, emulsion polymerization, suspension polymerization and surface imprinting technique) were illustrated. Furthermore, the applications of MMINs in the selective extraction of various antibiotic residues (sulfonamides, quinolones, tetracyclines, β-lactams, aminoglycosides and so on) in environmental and food samples were summarized. Finally, the existing problems and future prospects of MMINs were outlined in the final section of the review.

Preparation of dual recognition adsorbents based on molecularly imprinted polymers and aptamer for highly sensitive recognition and enrichment of ochratoxin A

In light of the significant risks that mycotoxins posed to public health and environmental safety, this research developed an adsorbent MIPs/Apt/AuNPs@ZIF-67 (MA-AZ) utilizing a dual-recognition approach combining molecularly imprinted polymers (MIPs) and aptamer (Apt). This innovative method enabled the effective and highly selective recognition and enrichment of ochratoxin A (OTA). ZIF-67 was utilized as a carrier with a substantial specific surface area, and gold nanoparticles (AuNPs) were loaded on its surface to fix the thiol-modified Apt on the surface of the carrier. Then, an initiator was used to initiate a polymerization reaction, and the generated MIPs coated Apt/AuNPs@ZIF-67, thereby synthesizing the MA-AZ with a "synergistic recognition" effect. The Apt significantly increased the number of recognition sites within the imprinted cavities, and MIPs played roles in identifying targets, fixing and protecting Apt. The combination of the both produced the effect of "1+1>2". The study on the adsorption performance of MA-AZ found that the adsorption capacity of MA-AZ could reach 65.1 mg/g, and the imprinted factor was 5.48. In addition, MA-AZ exhibited excellent stability, specificity, reusability and recovery rate. Thus, this study offers valuable insights for the recognition and enrichment of hazardous substances, and helps to promote the rapid development of safety detection.

Properties, evaluation and application of naringin magnetic molecularly imprinted polymer based on synergistic imprinting strategy

A novel and facile surface molecularly imprinted polymer coated on magnetic chitosan (Fe3O4@CS@MIP) was fabricated for the selective recognition and enrichment of naringin (NRG). The Fe3O4@CS@MIP was prepared based on covalent-noncovalent synergistic imprinting strategies, utilizing 4-vinyl phenyl boric acid as covalent functional monomer, deep eutectic solvent (choline chloride/methacrylic acid [ChCl/MAA]) as non-covalent functional monomer and Fe3O4@CS nanoparticles as the magnetic support. The obtained Fe3O4@CS@MIP exhibited a uniform morphology, excellent crystallinity, outstanding magnetic properties, and high surface area. Owing to the double recognition abilities, the resultant polymer showed exceptional binding performance and rapid mass transfer in phosphate buffer (pH 7.0). The maximum binding amount of Fe3O4@CS@MIP was found to be 15.08 mg g-1, and the equilibrium adsorption could be achieved within 180 min. Moreover, they also exhibited stronger selectivity for NRG and satisfactory reusability, with only 11.0% loss after five adsorption-desorption cycles. Additionally, the Fe3O4@CS@MIP, serving as an adsorbent, presented practical application potential in the separation and enrichment of NRG from pummelo peel, with extraction efficiency in the range of 79.53% to 84.63%. This work provided a new strategy for improving the performance of MIP and contributed an attractive option for the extraction of NRG in complex samples.

Reusable magnetic molecular imprinted polymers based on magnetic graphene oxide for selective identification and detection of eugenol in environmental water samples

In this study, a reliable method for determining eugenol content in environmental water samples was established by combining magnetic solid-phase extraction with high-performance liquid chromatography. Magnetic molecular imprinted polymers MGO@MIPs were prepared through surface molecular imprinting technique with eugenol as the template molecule. The material displayed good superparamagnetic properties and magnetic responsiveness in favor of rapid separation. The adsorption properties of MGO@MIPs for eugenol were evaluated through adsorption kinetics and selectivity experiments. MGO@MIPs were found to have favorable reusability and obvious selectivity for eugenol. In addition, adsorption and elution conditions were investigated. Under optimal conditions, a linear relationship was obtained between the concentration of eugenol and its peak area in the range of 0.02-5 mg/L (R2 = 0.9998) and the limit of detection was 4.0 × 10-6 mg/mL. The performance of the established method was assessed with the average recovery of 96.59-102.20% and the relative standard deviation (RSD) below 3.5%. The application of this method provides a new perspective for the separation, enrichment and detection of eugenol in water environment.

High enrichment and sensitive measurement of oxytetracycline in tea drinks by thermosensitive magnetic molecular imprinting based magnetic solid phase extraction coupled with boron doped carbon dots

As a typical kind of new pollutants, there are still some challenges in the rapid detection of antibiotics. In this work, a sensitive fluorescent probe based on boron-doped carbon dots (B-CDs) in combination with thermo-responsive magnetic molecularly imprinted polymers (T-MMIPs) was constructed for the detection of oxytetracycline (OTC) in tea drinks. T-MMIPs were designed, fabricated and employed to enrich OTC at trace level from tea drinks, and B-CDs were utilized as the fluorescent probe to detect the concentration of OTC. The proposed method exhibited good linear relationship with OTC concentration from 0.2 to 60 μg L-1 and the limit of detection was 0.1 μg L-1. The established method has been successfully validated with tea beverages. Present work was the first attempt application of T-MMIPs in combination with CDs in detection of OTC, and demonstrated that the proposed method endowed the detection of OTC with high selectivity, sensitivity, reliability and wide application prospect, meanwhile offered a new strategy for the method establishment of rapid and sensitive detection of trace antibiotics in food and other matrices.

Synthesis of Boronate Affinity-Based Oriented Dummy Template-Imprinted Magnetic Nanomaterials for Rapid and Efficient Solid-Phase Extraction of Ellagic Acid from Food

Ellagic acid (EA) is a natural polyphenol and possesses excellent in vivo bioactivity and antioxidant behaviors, which play an important role in the treatment of oxidative stress-related diseases, such as cancer. Additionally, EA is also known as a skin-whitening ingredient. The content of EA would determine its efficacy. Therefore, the accurate analysis of EA content can provide more information for the scientific consumption of EA-rich foods and cosmetics. Nevertheless, the analysis of EA in these samples is challenging due to the low concentration level and the presence of interfering components with high abundance. Molecularly imprinted polymers are highly efficient pretreatment materials in achieving specific recognition of target molecules. However, the traditional template molecule (EA) could not be absolutely removed. Hence, template leakage continues to occur during the sample preparation process, leading to a lack of accuracy in the quantification of EA in actual samples, particularly for trace analytes. In addition, another drawback of EA as an imprinting template is that EA possesses poor solubility and a high price. Gallic acid (GA), called dummy templates, was employed for the synthesis of MIPs as a solution to these challenges. The approach used in this study was boronate affinity-based oriented surface imprinting. The prepared dummy-imprinted nanoparticles exhibited several significant advantages, such as good specificity, high binding affinity ((4.89 ± 0.46) × 10-5 M), high binding capacity (6.56 ± 0.35 mg/g), fast kinetics (6 min), and low binding pH (pH 5.0) toward EA. The reproducibility of the dummy-imprinted nanoparticles was satisfactory. The dummy-imprinted nanoparticles could still be reused even after six adsorption-desorption cycles. In addition, the recoveries of the proposed method for EA at three spiked levels of analysis in strawberry and pineapple were 91.0-106.8% and 93.8-104.0%, respectively, which indicated the successful application to real samples.