Search results for "imprint"
showing 10 items of 194 documents
Surface initiated molecularly imprinted polymer films: a new approach in chiral capillary electrochromatography
2001
A new generation of imprinted composite particles was tested as capillary electrochromatography stationary phase. Silica particles characterised by a well defined particle size (10 µm diameter), shape and pore system (1000 A) were modified with an azoinitiator and subsequently used to graft molecularly imprinted polymers targeted to bind L-phenylalanine anilide. Fused silica capillaries were packed over a length corresponding to 8 cm, using a pneumatic amplification pump, and the stationary phase thus obtained was tested with respect to its electrochromatographic performance. The electroendosmotic flow mobility was evaluated with respect to both the different content of polymer on the silic…
Noncovalent molecular imprinting: antibody-like molecular recognition in polymeric network materials
1997
Abstract Molecular imprinting techniques allow the preparation of polymeric receptors which bind small molecules with affinities and selectivities of the same order as those observed in the binding of antigens by antibodies. The molecular imprinting technology has now reached a stage where the commercial use of imprinted materials is being assessed, notably for separations requiring strong and selective binding of small molecules. This development is driven by the potential advantages of polymeric receptors over biological in terms of stability, capacity, cost and ease of preparation. In this short review the state of the art of noncovalent imprinting is summarised indicating a few areas in…
Influence of the pH on the behavior of an imprinted polymeric stationary phase--supporting evidence for a binding site model.
2001
The equilibrium isotherms of the two enantiomers of phenylalanine anilide (PA) were measured by conventional frontal analysis at three different pH on a thermally-treated imprinted stationary phase selective for the L enantiomer. The first of these pH (buffer pH=3.0, pH(app)=4.0) is well below the apparent pKa (6.4) of the two solutes, the second (buffer pH=5.8, pH(app)=7.0) slightly below this pKa, and the third (buffer pH=7.0, pH(app)=8.3) well above it. The experimental data were fitted to several isotherm models. The best estimates of the parameters of these models are reported and discussed. The corresponding isotherms are compared with the experimental ones. The contributions of the e…
Application of Imprinted Synthetic Polymers in Binding Assay Development
2000
The first part of the review describes a method for the synthesis of molecularly imprinted polymers for use in binding assays. The method considers the many factors involved that affect the recognition properties of the materials and describes an approach to screening and optimization of these factors. The second part describes the development of binding assays using such polymers. This includes the use of different labels, the effect of solvent and buffer, the scale of the assay (amount of solid polymer), and how these influence the quality of the assay in terms of sensitivity, selectivity, and speed of analysis.
Application of molecularly imprinted polymers in supercritical fluid chromatography
2000
Molecularly imprinted polymers (MIPs), for the templates free base racemic propranolol and the L-enantiomer of phenylalanine anilide (L-PA), were investigated as stationary phases in supercritical fluid chromatography (SFC). Large retention differences were observed on the propranolol MIP for both the template molecule and the structural analogue metoprolol compared to that observed on the corresponding blank polymer. Mobile phase composition and solute concentration were found to affect this retention behaviour. The phenylalanine anilide MIP (L-PA MIP) was found to be enantioselective in SFC with stronger retention observed for the template enantiomer. Throughout the study, characteristic …
Imprinted chiral stationary phases in high-performance liquid chromatography
2001
Polymers imprinted with chiral templates offer a new generation of tailor-made chiral stationary phases (CSPs) with predictable selectivities. This review summarizes the present state of the art of molecular imprinting to generate tailor-made CSPs and provides an overview of the main factors involved in the manufacturing process that are crucial to the chromatographic performance of the phases.
Development of a semiautomated procedure for the synthesis and evaluation of molecularly imprinted polymers applied to the search for functional mono…
2001
Abstract A previously described scaled-down version of the established monolith procedure, where molecularly imprinted polymers (MIPs) are prepared on the bottom surface of chromatographic vials [Anal. Chem. 71 (1999) 2092] has been here further optimised with respect to its full automation. The protocol results in savings of time and reagents compared to the monolith procedure, allowing ca. 60 polymers (∼50 mg each) to be synthesised in parallel. Both blank and imprinted polymers are then evaluated in situ by equilibrium batch rebinding tests. Each step in the synthesis and evaluation was considered with the aim of achieving an automated method with wide applicability with regards to templ…
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…