Ternary deep eutectic solvent magnetic molecularly imprinted polymers for the dispersive magnetic solid‐phase microextraction of green tea

Ternary deep eutectic solvent magnetic molecularly imprinted polymers grafted on silica were developed for the selective recognition and separation of theophylline, theobromine, (+)‐catechin hydrate, and caffeic acid from green tea through dispersive magnetic solid‐phase microextraction. A new ternary deep eutectic solvent was adopted as a functional monomer. The materials obtained were characterized by FTIR spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, NMR spectroscopy, and powder X‐ray diffraction. The practical recovery of the theophylline, theobromine, (+)‐catechin hydrate, and caffeic acid isolated with ternary deep eutectic solvent magnetic molecularly imprinted polymers in green tea were 91.82, 92.13, 89.96, and 90.73%, respectively, and the actual amounts extracted were 5.82, 4.32, 18.36, and 3.69 mg/g, respectively. The new method involving the novel material coupled with dispersive magnetic solid‐phase microextraction showed outstanding recognition, selectivity and excellent magnetism, providing a new perspective for the separation of bioactive compounds.     

印迹分子聚合物结合低共熔溶剂用于山楂中咖啡酸的固相萃取

在相同的实验条件下,分别合成了以咖啡酸为模板的印迹分子聚合物和无模板分子聚合物。使用场发射扫描电镜法和吸附实验表征这两种聚合物材料的孔状结构和选择性吸附性能。然后利用印迹分子聚合物、无模板分子聚合物、C₁₈萃取小柱这3种材料结合固相萃取法纯化山楂提取物中的咖啡酸,提取率分别为3.46、1.01、1.17 μg/g。为了优化固相萃取过程,实验研究了不同洗脱剂的影响。分别利用用氯化胆碱和甘油、氯化胆碱和尿素(摩尔比均为1:2)合成出两种低共熔溶剂。甲醇与这两种低共熔溶剂分别以不同的体积比混合作为洗脱剂,用于优化咖啡酸的固相萃取过程。实验结果表明,印迹分子聚合物是一种良好的固相萃取材料;当甲醇和甘油基低共熔溶剂在体积比为3:1混合时,表现出最好的洗脱能力,得到咖啡酸的回收率为82.32%。     

Exploration of a ternary deep eutectic solvent of methyltriphenylphosphonium bromide/chalcone/formic acid for the selective recognition of rutin and quercetin in Herba Artemisiae Scopariae

Methyltriphenylphosphonium bromide/chalcone/formic acid, a green ternary deep eutectic solvent, was applied as a functional monomer and dummy template simultaneously in the synthesis of a new molecularly imprinted polymer. Ternary deep eutectic solvent based molecularly imprinted polymers are used as a solid‐phase extraction sorbent in the separation and purification of rutin and quercetin from Herba Artemisiae Scopariae combined with high‐performance liquid chromatography. Fourier transform infrared spectroscopy and field‐emission scanning electron microscopy were applied to characterize the deep eutectic solvent based molecularly imprinted polymers synthesized using different molar ratios of chalcone. The static and competitive adsorption tests were performed to examine the recognition ability of the molecularly imprinted polymers to rutin and quercetin. The ternary deep eutectic solvent consisting of formic acid/chalcone/methyltriphenylphosphonium bromide (1:0.05:0.5) had the best molecular recognition effect. After optimization of the washing solvents (methanol/water, 1:9) and eluting solvents (acetonitrile/acetic acid, 9:1), a reliable analytical method was developed for strong recognition towards rutin and quercetin in Herba Artemisiae Scopariae with satisfactory extraction recoveries (rutin: 92.48%, quercetin: 94.23%). Overall, the chalcone ternary deep eutectic solvent‐based molecularly imprinted polymer coupled with solid‐phase extraction is an effective method for the selective purification of multiple bioactive compounds in complex samples.     

Magnetic molecularly imprinted polymers for recognition and enrichment of polysaccharides from seaweed

New magnetic molecularly imprinted polymers with two templates were fabricated for the recognition of polysaccharides (fucoidan and alginic acid) from seaweed by magnetic solid‐phase extraction, and the materials were modified by seven types of deep eutectic solvents. It was found that the deep eutectic solvents magnetic molecularly imprinted polymers showed stronger recognition and higher recoveries for fucoidan and alginic acid than magnetic molecularly imprinted polymers, and the deep eutectic solvents‐4‐magnetic molecularly imprinted polymers had the best effects. The practical recovery of the two polysaccharides (fucoidan and alginic acid) purified with deep eutectic solvents‐4‐magnetic molecular imprinted polymers in seaweed under the optimal conditions were 89.87, and 92.0%, respectively, and the actual amounts extracted were 20.6 and 18.7 μg/g, respectively. To sum up, the developed method proved to be a novel and promising method for the recognition of complex polysaccharide samples from seaweed.     

Magnetic deep eutectic solvents molecularly imprinted polymers for the selective recognition and separation of protein

A novel and facile magnetic deep eutectic solvents (DES) molecularly imprinted polymers (MIPs) for the selective recognition and separation of Bovine hemoglobin (BHb) was prepared. The new-type DES was adopted as the functional monomer which would bring molecular imprinted technology to a new direction. The amounts of DES were optimized. The obtained magnetic DES-MIPs were characterized with fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), elemental analysis and vibrating sample magnetometer (VSM). The results suggested that the imprinted polymers were successfully formed and possessed a charming magnetism. The maximum adsorption capability (Q_max) and dissociation constant (K_L) were analyzed by Langmuir isotherms (R² = 0.9983) and the value were estimated to be 175.44 mg/g and 0.035 mg/mL for the imprinted particles. And the imprinted particles showed a high imprinting factor of 4.77. In addition, the magnetic DES-MIPs presented outstanding recognition specificity and selectivity so that it can be utilized to separate template protein from the mixture of proteins and real samples. Last but not least, the combination of deep eutectic solvents and molecular imprinted technology in this paper provides a new perspective for the recognition and separation of proteins.     

环丙沙星分子印迹聚合物的合成及识别性能研究

采用分子印迹技术合成了以环丙沙星为印迹分子,以甲基丙烯酸和4-乙烯基吡啶同时为功能单体的分子印迹聚合物。运用平衡结合实验研究了印迹聚合物的吸附特性和选择识别能力。Scatchard分析表明,在所研究的浓度范围内,分子印迹聚合物中形成了两类不同的结合位点。底物选择实验表明,这种聚合物对环丙沙星呈现高的选择结合能力。     

Magnetic molecularly imprinted polymers based on silica modified by deep eutectic solvents for the rapid simultaneous magnetic‐based solid‐phase extraction of Salvia miltiorrhiza bunge,Glycine max (Linn.) Merr and green tea

Novel magnetic molecularly imprinted polymers (MMIPs) with multiple‐template based on silica were modified by four types of deep eutectic solvents (DESs) for the rapid simultaneous magnetic solid‐phase extraction (MSPE) of tanshinone Ⅰ, tanshinone ⅡA, and cryptotanshinone from Salvia miltiorrhiza bunge; glycitein, genistein, and daidzein from Glycine max (Linn.) Merr; and epicatechin, epigallocatechin gallate, and epicatechin gallate from green tea, respectively. The synthesized materials were characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Single factor experiments were to explore the relationship between the extraction efficiency and four factors (the sample solution pH, amount of DESs for modification, amount of adsorbent, and extraction time). It was showed that the DES4‐MMIPs have better extraction ability than the MMIPs without DESs and the other three DESs‐modified MMIPs. The best extraction recoveries with DES4‐MMIP were tanshinone Ⅰ (85.57%), tanshinone ⅡA (80.58%), cryptotanshinone (92.12%), glycitein (81.65%), genistein (87.72%), daidzein (92.24%), epicatechin (86.43%), epigallocatechin gallate (80.92%), and epicatechin gallate (93.64%), respectively. The novel multiple‐template MMIPs materials modified by DES for the rapid simultaneous MSPE of active compounds were proved to reduce the experimental steps than single‐template technique, and increase the extraction efficiency.     

Urea decomposition: Efficient synthesis of pyrroles using the deep eutectic solvent choline chloride/urea

A simple and efficient method is reported for the synthesis of pyrroles via condensation of a series of tricarbonyl compounds with ammonia, which was generated in situ from decomposition of the deep eutectic solvent choline chloride/urea.     

Catalytical oxidation of styrene by molecularly imprinted polymer with phenylacetic acid as template

This letter used the molecular imprinting technology to build up the microenvironment around co-monomer bemin to mimic the cytochrome P450 catalyzing the epoxidation of styrene. The results showed that the conversion rates of products were obviously enhanced by molecularly imprinted polymers, compared to free heroin solution, using three kinds of oxidants. The used axial ligand in polymers synthesis also improved the total conversion rates.     

Preparation and characterization of a novel molecularly imprinted polymer for the separation of glycyrrhizic acid

Molecularly imprinted polymers of glycyrrhizic acid were prepared by solution polymerization using glycyrrhizic acid as the template molecule, N‐vinypyrrolidone as functional monomer, N ,N‐methylene bisacrylamide as cross‐linker and ascorbic acid and hydrogen peroxide as initiators. Focused on the adsorption capacity and separation degree of the polymer to glycyrrhizic acid, the effects of the monomers, crosslinker and initiators were investigated and optimized. Finally, the structure of the polymer was characterized by using Fourier transform infrared spectroscopy and scanning electron microscopy. To obtain objective results, non‐imprinted molecular polymers prepared under the same conditions were also characterized. The adsorption quantity of the polymer was measured by high‐performance liquid chromatography. Under the optimum conditions, the maximum adsorption capacity of glycyrrhizic acid approached 15 mg/g, and the separation degree was as high as 2.5. The adsorption kinetics could be well described by a pseudo‐first‐order model, while the thermodynamics of the adsorption process could be described by the Langmuir model.     

Photocontrolled extraction of uric acid from biological samples based on photoresponsive surface molecularly imprinted polymer microspheres

We aim to develop novel photoresponsive surface molecularly imprinted polymer (SIMP) microspheres, an SiO₂‐SIMP, for the photocontrolled extraction of uric acid from biological samples. The SiO₂‐SMIP was prepared on silica microspheres by surface polymerization and characterized by using scanning electron microscopy, transmission electron microscopy, FTIR spectroscopy, thermogravimetric analysis, nitrogen adsorption–desorption analysis, and UV‐visible spectroscopy. The SiO₂‐SMIP microspheres showed a photocontrolled uptake and release of uric acid in NaH₂PO₄ buffer upon alternate irradiation at 365 and 440 nm. The SiO₂‐SMIP microspheres were able to photocontrollably extract uric acid from complicated biological samples for concentration analysis with no significant interference encountered and it exhibited very good recognition ability and fast binding kinetics toward uric acid.     

Catalytical oxidation of styrene by molecularly imprinted polymer with phenylacetic acid as template and hemin as co-monomer

This letter used the molecular imprinting technology to build up the microenvironment around co-monomer bemin to mimic the cytochrome P450 catalyzing the epoxidation of styrene.The results showed that the conversion rates of products were obviously enhanced by molecularly imprinted polymers,compared to free hemin solution,using three kinds of oxidants.The used axial ligand in polymers synthesis also improved the total conversion rates.     

氯化胆碱/草酸型低共熔溶剂氧化脱除模拟油硫化物

通过氯化胆碱和草酸在100℃下搅拌,合成了氯化胆碱/草酸型低共熔溶剂。以氯化胆碱/草酸为催化剂、过氧化氢为氧化剂、咪唑氟硼酸盐离子液体为萃取剂氧化萃取一体法脱除模拟油中的二苯并噻吩(DBT)。考察了反应温度、反应时间、氧化剂加入量、萃取剂类型、硫化物类型等因素对脱硫效率的影响。结果表明,当以咪唑氟硼酸盐为萃取剂,n(H2O2)/n(S)=8、反应温度30℃、反应80 min时,二苯并噻吩的脱除率可以达到95%。催化剂重复使用5次后,脱硫率仍然保持在90%。     

Probing cavity versus surface preference of fluorescent template molecules in molecularly imprinted polystyrene microspheres

Functional polystyrene (PS) crosslinked microbeads were developed by dispersion polymerization as fluorescent molecularly imprinted polymers (MIPs) having cavities with specific recognition sites. The functional azobenzene molecule modified with pyridine was self‐assembled with Pyrenebutyric acid (template molecules), and introduced during the second stage of dispersion polymerization of polystyrene. The template molecule was removed from MIP by Soxhlet using acetonitrile as solvent. Non imprinted polymer (NIP) having no template was also synthesized for comparative study. Fluorescence spectroscopy could be used as a tool to derive insight into the location of the template molecules on the MIP or NIP. The template molecules were adsorbed on the surface of the NIPs during binding studies, which was evidenced from the pyrene excimeric emission observed at 440 nm. The template binding efficiency of the NIPs were much lower compared to MIPs. Pyrene emission from MIP upon rebinding showed typical monomeric emission in the 375–395 nm range, confirming its location in isolated cavities. In rebinding studies of the template molecules, the MIPs selectively took up the template for which the cavity was designed, which demonstrated their selectivity towards template molecules. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1558–1565     

Polydopamine‐coated magnetic molecularly imprinted polymer for the selective solid‐phase extraction of cinnamic acid,ferulic acid and caffeic acid from radix scrophulariae sample

We describe novel cinnamic acid polydopamine‐coated magnetic imprinted polymers for the simultaneous selective extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample. The novel magnetic imprinted polymers were synthesized by surface imprinting polymerization using magnetic multi‐walled carbon nanotubes as the support material, cinnamic acid as the template and dopamine as the functional monomer. The magnetic imprinted polymers were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The results revealed that the magnetic imprinted polymers had outstanding magnetic properties, high adsorption capacity, selectivity and fast kinetic binding toward cinnamic acid, ferulic acid and caffeic acid. Coupled with high‐performance liquid chromatography, the extraction conditions of the magnetic imprinted polymers as a magnetic solid‐phase extraction sorbent were investigated in detail. The proposed imprinted magnetic solid phase extraction procedure has been used for the purification and enrichment of cinnamic acid, ferulic acid and caffeic acid successfully from radix scrophulariae extraction sample with recoveries of 92.4–115.0% for cinnamic acid, 89.4–103.0% for ferulic acid and 86.6–96.0% for caffeic acid.     

EMIES/p-TsOH型低共熔溶剂的合成及其氧化脱硫性能的研究

通过1-乙基-3-甲基咪唑硫酸乙酯离子液体（EMIES）和对甲苯磺酸（p-TsOH）的混合物制备EMIES/p-TsOH型低共熔溶剂。其结构特征通过红外光谱、氢谱和热重技术进行了分析。并以EMIES/p-TsOH作为催化剂与萃取剂,H₂O₂作为氧化剂研究了其对模拟油中的硫化物的脱除性能。考察了反应温度、n（H₂O₂）/n（S）比、低共熔溶剂加入量及硫化物类型对脱硫效果的影响。在最佳的条件下,模拟油中二苯并噻吩（DBT）、4,6-二甲基二苯并噻吩（4,6-DMDBT）和苯并噻吩（BT）的脱除率分别为96.2%、92.2%和88.8%。经过五次循环使用后,DBT的脱除率仍达到93.6%。对该脱硫体系进行了动力学分析,其表观活化能为66.4kJ/mol。     

液晶分子印迹整体柱的制备及其分子识别热力学

液晶分子印迹聚合物(MIPs)因刚性液晶单体的加入而在超低交联度水平下也能印迹和识别模板分子,有效解决了传统MIPs因高交联度造成的位点包埋、结合容量低、传质慢等问题.尽管液晶MIPs具有如此独特的优势,但却面临着由于交联度的大幅度降低而导致印迹效果下降的问题.为了研究液晶MIPs的结合特性,制备具有良好印迹效果的低交...     

Hybrid molecularly imprinted polymers modified by deep eutectic solvents and ionic liquids with three templates for the rapid simultaneous purification of rutin,scoparone, and quercetin from Herba Artemisiae Scopariae

Different kinds of deep eutectic solvents based on choline chloride and ionic liquids based on 1‐methylimidazole were used to modify hybrid molecularly imprinted polymers with the monomer γ‐aminopropyltriethoxysilane‐methacrylic and three templates (rutin, scoparone, and quercetin). The materials were adopted as solid‐phase extraction packing agents, and were characterized by FTIR spectroscopy and field emission scanning electron microscopy. The hybrid molecularly imprinted polymers modified by deep eutectic solvents had high recoveries and a strong recognition of rutin, scoparone, and quercetin in Herba Artemisiae Scopariae than those modified by ionic liquids. In the procedure of solid‐phase extraction, deep eutectic solvents‐2‐hybrid molecularly imprinted polymers were obtained with the best recoveries with rutin (92.27%), scoparone (87.51%), and quercetin (80.02%), and the actual extraction yields of rutin (5.6 mg/g), scoparone (2.3 mg/g), and quercetin (3.4 mg/g). Overall, the proposed approach with the high affinity of hybrid molecularly imprinted polymers might offer a novel method for the purification of complex samples.     

Deep eutectic solvents skeleton typed molecularly imprinted chitosan microsphere coated magnetic graphene oxide for solid‐phase microextraction of chlorophenols from environmental water

Novel molecularly imprinted chitosan microspheres were prepared on the surface of magnetic graphene oxide, with deep eutectic solvents both as a functional monomer and template. The prepared molecularly imprinted chitosan microspheres‐magnetic graphene oxide was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, Brunauer‐Emmett‐Teller surface area, thermogravimetric analysis were subsequently combined with solid‐phase micro‐extraction for simultaneous separation and enrichment of the extraction of chlorophenols from environmental water. Factors affecting the extraction efficiency of chlorophenols were optimized using response surface methodology. The actual extraction capacities under the optimal conditions (liquid to solid ratio = 3, cycles of adsorption/desorption = 5, 40°C extraction temperature, and extraction time for 35 min) were 86.90 mg/g. Compared to the traditional materials, the molecularly imprinted chitosan microspheres‐magnetic graphene oxide produced higher selectivity and extraction capacity.     

Green and highly efficient synthesis of pyranopyrazoles in choline chloride/urea deep eutectic solvent

A simple and efficient multicomponent protocol, using ammonium deep eutectic solvent as a dual catalyst and environmentally benign reaction medium, is developed for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. This operationally simple protocol does not involve tedious workup or purification, affording the target compounds in short reaction times and excellent yields and avoiding the use of environmentally hazardous solvents and catalysts.