Search results for "IMPR"
showing 10 items of 1334 documents
Selective solid phase extraction of a drug lead compound using molecularly imprinted polymers prepared by the target analogue approach
2002
Molecularly imprinted polymers have been evaluated at the sample clean-up stage in the analysis of a drug lead compound. In order to circumvent quantification problems related to bleeding of the template, a structurally related analogue of the latter was used. This was selected based on criteria related to interaction site location, solubility, availability and stability of the analogue. Selection of suitable polymerisation conditions was then made using a small batch format (ca. 50 mg) and rapid assessment of binding in the equilibrium mode. It was found that the amount of template could be greatly reduced compared to the conventional protocol, requiring only 5 μmol of template per gram of…
Method for Synthesis and Screening of Large Groups of Molecularly Imprinted Polymers
2011
A technique for the synthesis of molecularly imprinted polymers (MIPs) in small scale (∼55 mg) coupled with direct in situ processing and batch rebinding evaluation is reported. The primary assessment is based on quantification by HPLC or UV absorbance measurement of the amount of template released from the polymer in a given solvent. This method allows a rapid screening of the parameters of importance to reach a desired level of binding affinity capacity and selectivity for a given target molecule. This was demonstrated for the triazine herbicide terbutylazine, where an initial screening was performed for the type of functional monomer used in the MIP preparation. Thus among the six functi…
Vapor-phase testing of the memory-effects in benzene- and toluene-imprinted polymers conditioned at elevated temperature.
2013
Abstract The preparation of polymers imprinted with common aromatic solvents such as benzene and toluene is an under-exploited subject of research. The present study was aimed at the understanding of whether true solvent memory effects can be achieved by molecular imprinting, as well as if they are stable at elevated temperature. A set of copolymers, comprising low and high cross-linking levels, was prepared from four different combinations of functional monomer and cross-linker, namely methacrylic acid (MAA)/ethylene glycol dimethacrylate (EGDMA), methyl methacrylate (MMA)/EGDMA, MAA/divinyl benzene (DVB) and MMA/DVB. Each possible combination was prepared separately in benzene, toluene an…
Hierarchical Imprinting Using Crude Solid Phase Peptide Synthesis Products as Templates
2003
The crude products resulting from solid-phase peptide synthesis can be used as epitope templates to generate surface-confined sites for the template and larger peptides containing the template motif. This offers a facile route to robust affinity stationary phases for the chromatographic separation of peptides.
Binding characteristics of molecularly imprinted polymers based on fungicides in hydroalcoholic media
2015
An iprodione-imprinted polymer was prepared by copolymerization of methacrylamide and ethylene glycol dimethacrylate using a noncovalent imprinting approach. Methacrylamide was chosen using molecular dynamics simulations. To concentrate iprodione from hydro-alcoholic solutions, batch sorption of iprodione on the imprinted polymer were conducted. The equilibrium time for iprodione sorption is 20 min, and the corresponding kinetic mechanism follows the pseudo-second order indicating a strong interaction between iprodione and the imprinted polymer. Langmuir, Freundlich, and Dubinin-Radushkevich models were used to fit the isotherm of iprodione sorption. The imprinted polymer was found to be mo…
Affinity Distributions of a Molecularly Imprinted Polymer Calculated Numerically by the Expectation-Maximization Method
2003
Affinity distributions are calculated from adsorption isotherm data obtained for the enantiomers of L- and D-phenylalanine anilide (PA) on native and thermally annealed polymers molecularly imprinted with L-PA. The calculation is obtained with an iterative algorithm called expectation-maximization that does not require prior fit of the data to an isotherm model before inversion and thus yields a distribution indicative of the data only. The results show bimodal distributions, suggestive of a two-site model describing relatively selective and nonselective adsorption modes of the L-enantiomer and a corresponding unimodal/nonselective adsorption mode for the D-enantiomer. The nonselective adso…
Molecularly imprinted composite materials via iniferter-modified supports
2002
Wide pore silica (DP = 100 nm) and gel-type or macroporous (12% nominal crosslinking density) Merrifield resins were modified with iniferter groups for grafting of crosslinked molecularly imprinted or non-imprinted polymer layers through quasi-living polymerisation. Prior to iniferter coupling, the silica supports were premodified by silanisation with p-(chloromethyl)phenyl trimethoxysilane. The iniferter groups were then introduced by reacting the resin-bound chloromethyl groups with sodium N,N-diethyldithiocarbamate. It was shown that the coupling yield, measured as the conversion of the chloromethyl groups, could be varied between 5 and 85% through kinetic control, with the fastest conve…
Enzyme-modified electrodes for biosensors and biofuel cells
2019
In biosensors and biofuel cells, it is often desirable to accelerate the electron transfer rate between the enzyme and electrode surface to improve the performance of the devices (sensitivity or power output). To this end, in this review, we focus on three important strategies available to improve the performance of enzyme-modified electrodes: the use of protein engineering, designer polymers, and the introduction of nanomaterials. Engineering the protein or proteins that constitute the biocatalytic elements allow tuning their stability, activity, and specificity. It can also allow changing the enzyme immobilization efficiency (adsorption vs. covalent immobilization, for example). If direct…
Distribution of molecularly imprinted polymer layers on macroporous silica gel particles by STEM and EDX
2005
Abstract Using transmission electron microscopy (TEM) in parallel and scanning mode (STEM) combined with energy dispersive X-ray spectroscopy (EDX) the distribution of molecularly imprinted polymer layers covalently grafted on the inner and outer surface of macroporous silica gel particles was observed. The grafting was achieved using a special initiator system ( iniferter ) and applied on a well known model system producing molecularly imprinted layers with l -phenyl alanine analide ( l -PA) as template. By staining the sample with RuO 4 before its embedment in epoxy resin and cutting ultra thin slices it was possible to identify the stained grafted polymer on the silica matrix by EDX. Bas…
Towards Plastic Electronics: Patterning Semiconducting Polymers by Nanoimprint Lithography
2002
The direct patterning of functional semiconducting polymers (see Figure) has been achieved with a nanoimprint lithography technique. The room‐temperature process described is time‐saving as repeated temperature cycling is not required. In addition, due to the direct patterning approach the need for further processing steps (plasma treatment) to pattern the underlying semiconducting material is eliminated.