Search

Highlights: [•] The combination of ionic liquid and metal ion as pivot to prepare monolithic MIPs was reported. [•] Polymerization factors on the imprinting effect of MIP monolith were investigated. [•] The imprinting effect of the MIP monolith can be controlled by different contents of ionic liquid. [•] The pivot-based imprinted monolith showed higher affinity to polar template molecule. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic column with high porosity and good permeability. The imprinted monolithic column was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), naproxon (template), 4-vinylpyridine, and ethylene glycol dimethacrylate, in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4 ). The influence of synthesis parameters on the retention factor and imprinting effect, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest imprinting factor on the imprinted monolithic column prepared with MA 0702 was 22, about 10 times higher than that prepared in absence of POSS. The comparisons between MIP monoliths synthesized with POSS and without POSS were made in terms of permeability, column efficiency, surface morphology and pore size distribution. In addition, thermodynamic and Van Deemter analysis were used to evaluate the POSS-based MIP monolith. [ABSTRACT FROM AUTHOR]

A new lanthanide metal-organic frameworks NKU-1 have successfully incorporated into poly (BMA- co -EDMA) monolith and evaluated by capillary electrochromatography (CEC). Lanthanide metal-organic frameworks [Eu 2 (ABTC) 1.5 (H 2 O) 3 (DMA)] (NKU-1) were synthesized by self-assembly of Eu(III) ions and 3,3′,5,5′-azo benzene tetracarboxylic acid ligands have been fabricated into poly(BMA- co -EDMA) monoliths. 1-Butyl-3-methylimidazolium tetrafluoroborate and N , N -dimethylformamide were developed as binary porogen obtaining homogeneous dispersibility for NKU-1 and high permeability for monolithic column. The successful incorporation of NKU-1 into poly(BMA- co -EDMA) was confirmed and characterized by FT-IR spectra, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer area scanning, and transmission electron microscopy. Separation ability of the NKU-1-poly (BMA- co -EDMA) monoliths was demonstrated by separating four groups of analytes in CEC, including alkylbenzenes, polycyclic aromatic hydrocarbon, aniline series and naphthyl substitutes. Compared with bare monolithic (column efficiency of 100,000 plates/m), the NKU-1-poly (BMA- co -EDMA) monoliths have displayed greater column efficiency (maximum 210,000 plates/m) and higher permeability, as well as less peak tailing. The results showed that the NKU-1-poly (BMA- co -EDMA) monoliths are promising stationary phases for CEC separations. [ABSTRACT FROM AUTHOR]

In this work, a method for improving imprinting efficiency of dual-templates molecularly imprinted polymer was developed based on strategy of metal ion as pivot. Two templates, naproxen (NAP) and ketoprofen (KET), were simultaneously imprinted using 4-vinylpyridine (4-VP) as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker with Co 2+ as pivot. A ternary mixture of dimethyl formamide (DMF)- dimethyl sulfoxide (DMSO)- 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4 ) was used as the porogenic system. The resulting metal ion mediated, dual-templates molecularly imprinted monolith (MDMIM) showed excellent selectivity to the templates and analogues. In contrast to traditionally formulated MIPs made with multi-templates, reduced recognition ability toward targeted analytes on the MDMIM was not found. The structural properties of MDMIM were determined from Fourier transform infrared spectra, mercury intrusion and extrusion experiments and nitrogen adsorption–desorption isotherms. The MDMIM was then tested in the chromatographic mode due to its ability to recognize the templates. The studies of Van’t Hoff analysis indicated that the separation of the templates and their analogues on the MDMIM was an enthalpy controlled process. Collectively, metal ion as pivot is demonstrated as an effective method of imprinting dual-templates simultaneously without loss of selectivity. [ABSTRACT FROM AUTHOR]

Abstract: Molecular crowding is a new approach to promoting molecular imprinting more efficiently. In this work, this concept was applied to the preparation of imprinted monoliths in the presence of molecular crowding agent for stabilizing binding sites and improving molecular recognition. The imprinted monolithic column was synthesized using a mixture of enrofloxacin (template), methacrylic acid, ethylene glycol dimethacrylate, and polystyrene (molecular crowding agent). Some polymerization factors, such as template–monomer molar ratio and the composition of the porogen, on the imprinting effect of resulting MIP monolith were systematically investigated. Moreover, a stoichiometric displacement model for retention was successfully applied to evaluate the interaction between the solute and the stationary phase. Compared with the MIP prepared by conventional polymerization, the molecular crowding-based monolithic MIPs showed higher selectivity. The results suggested that molecular crowding is a powerful strategy to increase the effect of molecular imprinting. [Copyright &y& Elsevier]

Abstract: This report provided the first example of using pivot concept to prepare monolithic molecularly imprinted polymers (MIPs) with ketoprofen (KET) imprints, in which metal ions were employed as mediator between the functional monomer and the template to achieve higher fidelity of imprint. To solve metal ions in pre-polymerization system, a new ternary porogen of dimethyl sulfoxide–toluene–isooctane was developed for preparation of MIP monoliths with high porosity and good permeability. The effect of polymerization parameters such as the nature of metal ions, the ratio of template to metal ion and the degree of crosslinking, on the permeability, morphology and affinity of the metal ion mediated MIP monolith were studied. The experiments demonstrated that Ni2+, Co2+ and Zn2+ can be applied as pivot to prepare KET-imprinted monolith. Relative to monolithic MIP without metal ions, all the ion-mediated macropore MIP monoliths showed enhanced permeability, capacity factor and selectivity factor. High permeability (1.06×10−7 mm2) was obtained on the Co2+-mediated MIP monolith and great selectivity factor (3.84) was achieved on the Ni2+-mediated one. The stoichiometric displacement model was constructed to investigate the recognition mechanism of metal-ion mediated MIP. The results indicate that metal ion as pivot not only improves the affinity but also allows the fine-tuning on the macroporous structure of MIP monolith. [Copyright &y& Elsevier]

• HIPE monolith was prepared as matrix and AuNRs as intermediate ligands to bind trypsin. • The monolithic IMERs show excellent hydrophilicity and fast mass transfer. • 1127 Proteins were identified for rat liver proteins by the HIPE monolithic IMER. • Digestion outcomes of BSA by IMER were superior to in-solution digestion. A new macroporous immobilized trypsin reactor (IMER) based on high internal phase emulsion (HIPE) monolith has been designed in view of fast mass transfer of macromolecule. The concentrated emulsion consisted of a mixture of glycidyl methacrylate, divinylbenzene and deionized water, in which contained a suitable surfactant and an initiator. The resulting polyHIPE monolith was sequentially modified with ammonia and gold nanorods (AuNRs). Finally, trypsin was immobilized on the surface of the monolith by forming Au-S bonds between the AuNRs and the free thiol groups of trypsin. The digestion time of bovine serum albumin (BSA) on the IMER has been greatly shortened than that of in-solution digestion (10 min vs. 12 h), and the number of detected peptides has been significantly increased (114 vs. 84) with the sequence coverage improved effectively (91.6% vs. 82.7%). By digestion of the proteins extracted from rat livers with the IMER, 1127 protein groups (6901 peptides) were identified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). All these results above suggested that the monolithic IMER with open pore structure in place of monolith with conventional structures of particle packing can improve the efficiency of digestion of proteins significantly and has great application potential in proteomics analysis. [ABSTRACT FROM AUTHOR]