Dummy molecularly imprinted polymers based on a green synthesis strategy for magnetic solid-phase extraction of acrylamide in food samples

Potential Adsorption of Heavy Metal Ions by Eugenol Compounds and Derivatives through Ion Imprinted Polymer

Research on the potential of Ion Imprinted Polymer (IIP) selective adsorption of heavy metals using eugenol compounds and their derivatives has been carried out. Isolation and synthesis of eugenol derivatives with metal selective active groups and their use as selective metal carriers have been carried out with satisfactory results. Carrier effectiveness can still be improved by methods that focus on the target molecule recognition model. This adsorption method is called Ion Imprinted Polymer (IIP). The main components of IIP are functional monomers, crosslinkers, and target molecules. The use of acrylamide and its derivatives as functional monomers is useful with a lot of success achieved but also invites danger because it includes carcinogenic substances, a nerve poison, and so on. Moreover, the N group, which is an active acrylamide group, and its derivatives are only selective towards borderline metals (HSAB theory). Alternatives that are safe and can increase their selectivity are therefore needed. Eugenol, with its three potential functional groups, is believed to be able to replace the function of acrylamide and its derivatives that can even increase the effectiveness of IIP. The purpose of this study is to determine the potential of eugenol derivatives as selective adsorbents through the IIP method. This synthesis of IIP involved the use of basic ingredients of eugenol and its derivatives (polyeugenol, EOA, polyacetate). Each base material is contacted with a metal template then crosslinked with three kinds of crosslinking agents, namely EGDMA, DVB, and bisphenol. IIP is formed after the metal template is released using acid/HCl. The outcomes obtained demonstrate that the IIP method is able to increase the metal adsorption capacity and that the IIP method for metals is largely determined by the release of metals, which will form a hole for metal entry through adsorption. Poly-Cd-DVB, Eug-Cr-DVB, Poly-Cu-bisphenol, Polyacetate -Cr-DVB are polymer materials that have the potential to make up an IIP.

Metal organic framework assisted in situ complexation for miniaturized solid phase extraction of organic mercury in fish and Dendrobium officinale

Zirconium-based metal-organic frameworks, namely Zr-based MOF, was employed as adsorbent material in the miniaturized solid phase extraction of organic mercury compounds in food prior to capillary electrophoresis-diode array detector analysis. The synthesized adsorbent was characterized by different spectroscopic techniques. Parameters influencing the extraction and complexation of methylmercury chloride, ethylmercury chloride and phenylmercury chloride such as type of eluent solvent, type and amount of adsorbent were investigated. In addition, linear ranges contained 2.00-300.00 ng mL^-1 for MeHg⁺, 5.00-500.00 ng mL^-1 for EtHg⁺ and PhHg⁺, and the established method presented good linearity (R² ≥ 0.998). Under the optimized experimental conditions, the ranges of detection limit and quantitation limit were 0.022-0.067 ng mL^-1 and 0.073-0.220 ng mL^-1, respectively. The relative standard deviations of intra- and inter-day analysis were less than 3.2 and 3.1%, respectively. Trueness of the present method was successfully accomplished by means of the recovery assays (81.4-98.5%) in the blank samples with two concentration levels. The repeatability %RSD of the method was lower than 2.7%. Overall, the developed approach proved to have the latent capability to be utilized in routine analysis of organic mercury compounds in fish and Dendrobium officinale.

Optimization by response surface methodology of a dispersive magnetic solid phase extraction exploiting magnetic graphene nanocomposite coupled with UHPLC-PDA for simultaneous determination of new oral anticoagulants (NAOs) in human plasma

In this paper a dispersive magnetic-solid phase extraction (MSPE) using a graphene nanocomposite (rG/Fe₃O₄) followed by ultra high performance liquid chromatography with photodiode array detection has been developed for the simultaneous analysis of new class of oral anticoagulants (NOAs) in human plasma. The performance of the nanocomposite graphene@Fe₃O₄ on the magnetic solid phase extraction of apixaban, rivaroxaban and dabigatran has been optimized using a Box-Behnken design of experiment. The amount of graphene nanocomposite, the sample pH and the adsorption time were the investigated parameters as a function of the extraction recovery. The analytical method was fully validated based on linearity, limit of detection (LOD), limit of detection (LOQ), inter- and intra-day precision and trueness, and extraction yield. Under optimal condition, excellent linearity (R² > 0.9987) over the range (0.001-5.0 μg/mL), limit of detection (0.003 μg/mL), precision (0.81-8.97% RSD) and trueness (-5 to 9 % BIAS%) were observed for the target drugs. The average extraction recovery under optimal from plasma samples ranged between 96.6-98.6% for apixaban, rivaroxaban and dabigatran and the internal standard. The proposed method was developed, validated and successfully applied to the measurement of these NOAs in patients. The new approach offers an attractive alternative for the simultaneous analysis of the selected NOAs from plasma samples, providing several advantages including fewer sample preparation steps, ease of performance, and higher recoveries compared to traditional methodologies.

Green synthesis of magnetic carbon nanodot/graphene oxide hybrid material (Fe3O4@C-nanodot@GO) for magnetic solid phase extraction of ibuprofen in human blood samples prior to HPLC-DAD determination

In this study, a green production method was used to obtain magnetic carbon nanodot/graphene oxide hybrid material (Fe₃O₄@C-nanodot@GO) for the magnetic solid phase extraction (MSPE) of ibuprofen (IBU) in human plasma prior to HPLC-DAD determination. For the first time in the literature, Fe₃O₄@C-nanodot@GO hybrid material was synthesized and used as an adsorbent. C-nanodots were produced from pasteurized cow milk by using a simple and cheap hydrothermal method. After production of the C-nanodots and GO, Fe₃O₄@C-nanodot@GO hybrid material was fabricated in green solvent medium by using an one-step hydrothermal method. The method was based on the simple separation, preconcentration and analysis of ibuprofen by using MSPE-HPLC-DAD combination. The concentration changes of ibuprofen in human bloods against time were successfully monitored by using this combined method. For this purpose, blood samples were taken from volunteers at certain intervals after the administration of a certain dose of ibuprofen, and the MSPE method was used to monitor the concentration changes of ibuprofen in the blood samples. Experimental variables affecting the extraction efficiency of IBU such as sample solution pH, amount of adsorbent, extraction time, eluent type and volume were studied and optimized in the details. The characterization studies for the Fe₃O₄@C-nanodot@GO were carried out by X-ray diffraction spectrometry (XRD), Fourier transform infrared spectrometry (FT-IR), Raman spectrometry (Raman), energy dispersive x-ray (EDX), vibrating sample magnetometry (VSM) and scanning electron microscopy (SEM) techniques. Under the optimum experimental conditions, the limit of detection (LOD) was 8.0 ng mL^-1 and the recoveries at three spiked levels in human plasma were ranged from 91.0% to 95.0% with the relative standard deviation (RSD %) less than 4.0 % (n = 6). The results show that together use of MSPE with HPLC-DAD provides a simple and rapid analysis of ibuprofen in human plasma samples.

Magnetic hyperbranched molecularly imprinted polymers for selective enrichment and determination of zearalenone in wheat proceeded by HPLC-DAD analysis

A novel magnetic surface molecular imprinted polymers with 2, 4, 6-trisacrylamido-3, 5-triazine (TAT) as a functional monomer was successfully synthesized and used for the enrichment and determination of zearalenone. The molecular imprinting is reported herein at first time for application of zearalenone in wheat. The magnetic imprinted materials possessed excellent magnetism and uniform appearance, which were characterized by fourier transform infared spectroscopy and transmission electron microscope. The results proved the magnetic molecular imprinted polymers was successfully prepared. The magnetic molecular imprinted polymers exhibited satisfactory sensitivity, stability and potential reusability. The binding affinity was investigated by selectivity experiment, which possessed high selectivity. To obtain the optimal application conditions, the amount of adsorption, extraction time, elution solvent and time were optimized. The limited detection of zearalenone was 0.55 ng g^-1 and the recoveries of zearalenone were 92.1-96.0%. The relative standard deviation was lower than 5.4%. This indicated that a simple, efficient and low-cost method was established and successfully applied in spiked wheat sample.

Theoretical and experimental proof for selective response of imprinted sorbent - analysis of hordenine in human urine

The objective of this paper was to extend comprehensive theoretical and experimental investigations at the molecular level to identify factors responsible for the high selectivity of imprinted sorbents. This knowledge was utilized in a new analytical strategy devoted to the analysis of hordenine in human urine after beer consumption. Among the various polymeric compositions tested, the most effective material was built up from methacrylic acid and ethylene glycol dimethacrylate (MIP1), showing a satisfactory binding capacity (4.44 ± 0.15 µmol g^-1) and high specificity towards hordenine (AF = 5.90). The comprehensive analyses of porosity data and surface measurements revealed differences between imprinted polymers. The characterization of binding sites of MIP1 revealed a heterogeneous population with two values of K_d (2.75 and 370 μmol L^-1) and two values of B_max (1.82 and 99 μmol g^-1) for higher and lower affinity respectively. The extensive theoretical analyses of interactions between various analytes and the MIP model cavity showed the highest binding energy for hordenine (ΔE_B1 = -175.17 kcal mol^-1). The method was validated for selectivity, lowest limit of quantification, calibration curve performance, precision, accuracy, matrix effect, carry-over and stability in urine. Extracts were prepared according to guidelines of the European Medicines Agency. The validation criteria were fulfilled, and the method was satisfactorily applied to urine samples collected prior to, and 2 h after, consumption of 2 L of beer, revealing the presence of hordenine at the mean level of 129 ± 27 ng mL^-1. Additionally, ability of the sorbent to purify the urine sample was assessed using flow injection analysis tandem mass spectrometry, for comparison with other extraction techniques.

A dual-step immobilization/imprinting approach to prepare magnetic molecular imprinted polymers for selective removal of human serum albumin

One viable solution to improve the conformational stability of template proteins is to use multiple, weaker modes of action to immobilize proteins on the surfaces of a solid support. Herein, we introduce a novel surface imprinting technique for human serum albumin (HSA) by a dual immobilization/imprinting strategy. Specifically, HSA was first conjugated to the surfaces of magnetic Fe₃O₄ nanoparticles through a reversible aldmine condensation reaction. Dopamine (DA) was then used to imprint the protein template via an auto-polymerization reaction in biocompatible aqueous media. The resultant magnetic molecular imprinted polymers (MMIPs) possess high adsorption capacity (70.2 mg g^-1), superior selectivity (IF = 4.54), and rapid capturing kinetics to HSA (within 20 min). We successfully demonstrate the practical applicability of MMIPs to the selective removal of HSA from human serum sample. Our work offers a novel and robust solution to develop proteins imprinted materials with high binding capacity and selectivity. We anticipate such materials will find wide applications to protein detection or removal in diverse real-life clinical and biological samples.

Molecularly Imprinted Phase-Change Microcapsule System for Bifunctional Applications in Waste Heat Recovery and Targeted Pollutant Removal

An innovative design of a molecularly imprinted phase-change microcapsule (MIM) system for bifunctional applications in waste heat recovery and targeted pollutant removal was reported in this work. This molecularly imprinted system was successfully constructed by encapsulating n-eicosane with a SiO₂ base shell through emulsion-templated interfacial polycondensation and then coating a molecularly imprinted polymeric layer with bisphenol A (BPA) as a template molecule through surface free-radical polymerization. The morphology, microstructure, and chemical structure of the resultant molecularly imprinted phase-change microcapsules (MIMs) were characterized, and their phase-change behavior, thermal energy-storage performance, and selective adsorption capability were investigated intensively. The MIMs developed in this study achieved an outstanding latent heat-storage capability with a high capacity more than 165 J/g and also showed an excellent phase-change reliability with a very small fluctuation in phase-change temperatures and enthalpies after 500 thermal cycles. Moreover, the MIMs also presented a high thermal stability over 200 °C and good shape stability up to 120 °C. Most of all, an effective specific recognition capability and high recognition efficiency were achieved for the MIMs due to the formation of BPA-molecular imprinting sites on their surface. As a result, the MIMs exhibited good adsorption selectivity toward the BPA molecules and satisfactory reusability for targeted removal of BPA with a removal efficiency of 61.7% after 10 cycles of the rebinding-elution procedure. In view of a smart combination of thermal energy-storage and selective adsorption functions, the MIMs developed in this study demonstrate a great potential in applications for waste heat recovery and targeted pollutant removal of industrial and domestic wastewaters.

Selective determination of some beta-blockers in urine and plasma samples using continuous flow membrane microextraction coupled with high performance liquid chromatography

In this work, an efficient method termed as continuous flow membrane microextraction coupled with high performance liquid chromatography is introduced for a highly selective determination of metoprolol and propranolol in the biological samples. According to this method, an aqueous source phase of the analytes (donor phase, 10 mL) is circulated into an extraction cell, which is separated from an aqueous acceptor phase (100 μL) by a small piece of polypropylene membrane sheet whose pores are impregnated by an organic solvent (1-octanol, 15 μL). The analytes are extracted from the donor phase into the organic solvent. They are subsequently selectively back-extracted into the acceptor solution due to the pH gradient. The proposed method is very convenient and has the capability of being fully automated. It provides a good preconcentration and an excellent repeatability. The extractant is an aqueous phase, and by prevention of the extraction of macromolecules through the membrane, the developed method provides a high sample clean-up. In order to maximize the extraction efficiency, the influential parameters including the type of mediator solvent, pH values for the donor and acceptor solutions, extraction time, ionic strength, stirring rate, and volume of the acceptor solution are optimized. The calibration curves were obtained with a reasonable linearity (r² = 0.999) in the range of 3-1000 ng mL^-1. The limits of detection were 0.5 and 1.0 ng mL^-1, and excellent relative standard deviations were obtained (between 3.2% and 4.0%). Finally, the reliability of the procedure is evaluated by determination of metoprolol and propranolol in the human urine and plasma samples, which indicates the suitability, sensitivity, and high sample clean-up of the proposed method.

A chitosan solution-based vortex-forced matrix solid phase dispersion method for the extraction and determination of four bioactive constituents from Ligustri Lucidi Fructus by high performance liquid chromatography

A simple and efficient sample preparation method to extract four bioactive compounds (echinacoside, specnuezhenide, oleuropein and nuezhenoside G13) from Ligustri Lucidi Fructus was established by vortex-forced matrix solid phase dispersion (VFMSPD) method. Chitosan solution was applied as green eluent in this procedure and Celite AZO was employed as dispersant. High performance liquid chromatography (HPLC) equipped with ultraviolet (UV) detector was used to analyze the target analytes. The best result of the investigation was obtained with Celite AZO as dispersant, sample/ dispersant ratio as 1:1, grinding for 2 min, 1 mL high-viscosity chitosan solution (0.5 mg mL^-1) used as the elution reagent and vortex mixing for 1.5 min. The method exhibit a good linearity for the analytes (r² > 0.999). The absolute recoveries of the four target compounds in Ligustri Lucidi Fructus ranged from 90.7% to 98.8% and the relative recoveries of the target compounds ranged from 99.2% to 102% (RSD ≤ 3.4%), which were obtained by the final optimization method. Consequently, the newly developed chitosan solution-based vortex-forced matrix solid phase dispersion (MSPD) combined with HPLC could be efficiently applied to extract and analyze the target compounds in Ligustri Lucidi Fructus samples.

Recent Advances and Perspectives of Molecularly Imprinted Polymer-Based Fluorescent Sensors in Food and Environment Analysis

Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed.

Retention and molecular-recognition mechanisms of molecularly imprinted polymers for promazine derivatives

Monodisperse molecularly imprinted polymers (MIPs) for promazine derivatives [promazine (PZ), methylpromazine (MPZ), chlorpromazine (CPZ) and bromopromazine (BPZ)], MIP_PZ, MIP_MPZ, MIP_CPZ and MIP_BPZ, were prepared using methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate as a crosslinker by multi-step swelling and polymerization. The retention and molecular-recognition properties of the obtained MIPs were evaluated using LC in hydrophilic interaction chromatography (HILIC) and reversed-phase modes. In computational approaches, intermolecular interaction modes and energies between PZ derivatives and MAAs were evaluated at the HF/6-311G(d,p) level. The interaction energies of PZ, MPZ, CPZ and BPZ with 4 equivalents of MAAs were calculated. The results indicated that the interaction of the aliphatic amine moiety of a PZ derivative with MAA gave almost similar interaction energies at the HF/6-311G(d,p) level, and that the interaction of the sulfur atom of a phenothiazine scaffold with MAA was also the case. The third interaction of the aromatic amine of a PZ derivative with MAA was in the order of MPZ > PZ > CPZ > BPZ presumably due to the change of basicity by the electron-donating or electron-withdrawing effect of a subsituent. Furthermore, the fourth attractive modes of CPZ and BPZ were suggested to be the interaction of their halogen atoms with MAA through both halogen bonding and hydrogen bonding, while PZ and MPZ were suggested to have the weak C-H ⋅⋅⋅ π interaction with MAA. In HILIC mode, the interaction energies at the HF method had good correlation with the retention factor of a PZ derivative on each MIP, indicating that in addition to the shape recognition, the attractive electrostatic interactions would be more responsible for its retention rather than the dispersion energies. Furthermore, in addition to the shape recognition, ionic and hydrophobic interactions, and halogen bonding and hydrogen bonding (the last interaction seems to be weak) seem to work for the retention and molecular-recognition of PZ derivatives on the MIPs in reversed-phase mode.

Preparation and application of magnetic molecular imprinted polymers for extraction of cephalexin from pork and milk samples

A highly selective and effective method was successfully developed using magnetic molecular imprinted polymers (MMIPs) as solid-phase extraction (SPE) coupled with high performance liquid chromatography-ultraviolet detector (HPLC-UV) to rapidly determine cephalexin (CFX) in complex animal-derived food. MMIPs were creatively synthesized via suspension polymerization using Fe₃O₄ magnetic nanoparticles as supporter, CFX as template, acrylamide (AM) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The MMIPs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The binding process fitted well with pseudo-second-order model with good selectivity. Scatchard plot analysis suggested that MMIPs have two types of binding sites with the Q_max of 24.18 mg g^-1 and 40.25 mg g^-1, respectively. And Langmuir model proved that the recognition sites were uniformly distributed in a monolayer on the surface of MMIPs. The methodological assessment showed good applicability of MMIPs with excellent recovery (85.5%-94.0%), precision (1.2%-2.4%), and stability (intra-day 1.3%-3.6%; inter-day 2.6%-4.3%) in determining CFX content. In addition, the linearity of the calibration curve was good in the range of 0.02-5.00 mg L^-1, with a sensitive detection limit of 5.00 μg kg^-1. The results above suggest that the obtained MMIPs exert good performance for separation of CFX in animal-derived food, and the proposed method is suitable for the reliable determination of CFX in complex samples.

An ultrasound-assisted photocatalytic treatment to remove an herbicidal pollutant from wastewaters

Pollutants of emerging concern contaminate surface and ground water. Advanced oxidation processes treat these molecules and degrade them into smaller compounds or mineralization products. However, little information on coupled advanced oxidation techniques and on the degradation pathways of these pollutants is available to identify possible ecotoxic subproducts. In the present work, we investigate the ultrasound assisted photocatalytic degradation pathway of the herbicide Isoproturon. We worked in batch mode in a thermostatic glass reactor. We compared the activity of nanometric TiO₂ P25 with that of Kronos 1077, a micrometric TiO₂. We discuss the individual, additive and synergistic degradation action of photolysis, sonolysis, sonophotolysis, and sonophotocatalysis by varying catalyst loading and/or ultrasound power for the last three techniques. With 0.1 g L^-1 catalyst, photocatalysis and sonophotopcatalysis completely degrade Isoproturon within 240 min and 60 min, respectively (>99% conversion). Sonophotocatalysis breaks Isoproturon down into smaller molecules than photocatalysis alone.

Molecularly Imprinted Materials for Selective Biological Recognition

Molecular imprinting is an approach of generating imprinting cavities in polymer structures that are compatible with the target molecules. The cavities have memory for shape and chemical recognition, similar to the recognition mechanism of antigen-antibody in organisms. Their structures are also called biomimetic receptors or synthetic receptors. Owing to the excellent selectivity and unique structural predictability of molecularly imprinted materials (MIMs), practical MIMs have become a rapidly evolving research area providing key factors for understanding separation, recognition, and regenerative properties toward biological small molecules to biomacromolecules, even cell and microorganism. In this review, the characteristics, morphologies, and applicability of currently popular carrier materials for molecular imprinting, especially the fundamental role of hydrogels, porous materials, hierarchical nanoparticles, and 2D materials in the separation and recognition of biological templates are discussed. Moreover, through a series of case studies, emphasis is given on introducing imprinting strategies for biological templates with different molecular scales. In particular, the differences and connections between small molecular imprinting (bulk imprinting, "dummy" template imprinting, etc.), large molecular imprinting (surface imprinting, interfacial imprinting, etc.), and cell imprinting strategies are demonstrated in detail. Finally, future research directions are provided.

Fabrication of Water-Compatible Molecularly Imprinted Resin in a Hydrophilic Deep Eutectic Solvent for the Determination and Purification of Quinolones in Wastewaters

A novel water-compatible molecularly imprinted resin was prepared in a green solvent deep eutectic solvent (DES). Resorcinol and melamine, as functional monomers with an abundant hydrophilic group, such as –OH, –NH₂ and –NH–, were introduced into the molecularly imprinted resin (MIR). Three DESs (choline chloride-ethylene glycol, tetramethylammonium bromide-ethylene glycol and tetramethylammonium chloride-ethylene glycol) were used to synthesize the molecularly imprinted resin and the resulting deep eutectic solvent-based molecularly imprinted resins were characterized by particle size analysis, elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The resulting deep eutectic solvent-based molecularly imprinted resins were then applied to the adsorption of quinolones (ofloxacin) in water. The adsorption process of deep eutectic solvent-based molecularly imprinted resin followed the static adsorption model, Langmuir isotherm (R² ≥ 0.9618) and kinetic model pseudo-second-order (R² > 0.9814). The highest theory adsorption ability of the three kinds of deep eutectic solvent-based molecularly imprinted resins was more than 23.79 mg/g. The choline chloride-ethylene glycol-based MIR was applied to solid-phase extraction for the determination and purification of quinolones (e.g., ciprofloxacin and ofloxacin). The detection limit of deep eutectic solvent-based molecularly imprinted resin-solid-phase extraction method was less than 0.018 mg/L. The recoveries of the deep eutectic solvent-based molecularly imprinted resin-solid-phase extraction method at three spiked levels were 88.7–94.5%, with a relative standard deviation of ≤4.8%. The novel deep eutectic solvent-based molecularly imprinted resin-solid-phase extraction method is a simple, selective and accurate pre-treatment method and can be used to determine the quinolones in environmental water.

Extraction of oleuropein and luteolin-7-O-glucoside from olive leaves: Optimization of technique and operating conditions

Olive leaves have become a promising source of phenolic compounds and flavonoids with high added value. Phenolic compounds and flavonoids are important sources of antioxidants and bioactives, and one of the processes used to effectively produce them is extraction via solvents, using aqueous ethanol solutions. To obtain the highest extraction yield per kg of biomass, olive leaves were extracted using a conventional technique (dynamic maceration) and an emerging technology, such as pressurized liquid extraction. Studies of the factors that influence these processes were performed: temperature, leaf moisture content, solvent/solid, and aqueous ethanol concentration were optimized using the central composite and Box-Behnken experiment designs. Pressurized liquid extraction resulted in more efficient oleuropein and luteolin-7-O-glucoside extraction than dynamic maceration. The operational conditions for maximizing the recovery of phenolic compounds and flavonoids and antioxidant capacity were determined to be 190 °C, leaf moisture content of 5%, and aqueous ethanol concentration of 80%.

Extraction of atenolol from spiked blood serum using a molecularly imprinted polymer sorbent obtained by precipitation polymerization

Atenolol (ATE) is a cardio-selective β-blocker that is used in the treatment of hypertension over extended periods. However, ATE, like propranolol, has major potential for misuse as a performance-enhancing drug in several sports. Therefore, an efficient and selective separation method is required to detect and monitor the level of ATE in the body. This paper presents a molecularly imprinted polymer with specific and selective binding to ATE using precipitation polymerization. We show that when employed in an optimized molecular imprinted solid phase extraction (MI-SPE) protocol, recoveries of 93.65 ± 1.29% from spiked blood serum with excellent discrimination from other β-blocker drugs is possible. The methodology used in this study includes molecular modeling interaction between ATE and itaconic acid (ITA) as functional monomer, followed by determination of binding constants with spectrophotometry, synthesis of the polymer using precipitation polymerization and ending with characterization and application of polymers to extract ATE in serum. Docking analysis revealed a binding affinity between ATE and ITA of −2.0 kcal/mol with the formation of hydrogen bonding. The association constant between ATE and ITA was studied by UV titration in two different solvents, with evidence of an association constant 6.277 × 10² M⁻¹ measured in acetonitrile: methanol (1:1). An optimized MI-SPE protocol was developed for the extraction of ATE from spiked blood serum, obtaining recoveries of 93.65% with excellent selectivity toward other β-blocker drugs.

Synthesis of DABCO-based ionic liquid functionalized magnetic nanoparticles as a novel sorbent for the determination of cephalosporins in milk samples by dispersive solid-phase extraction followed by ultra-performance liquid chromatography-tandem mass spectrometry

In this study, DABCO-based ionic liquid-functionalized magnetic iron oxide nanoparticles were synthesized for the first time by the quaternization reaction with 1-(2,3-dihydroxypropyl)-1,4-diazabicyclo[2.2.2]octanylium chloride and chloro-functionalized Fe₃O₄ nanoparticles.