Hierarchical Imprinting Using Crude Solid Phase Peptide Synthesis Products as Templates

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.

Target Analogue Imprinted Polymers with Affinity for Folic Acid and Related Compounds

Two approaches to synthesize molecularly imprinted polymers with affinity for folic acid and other substituted pteridines have been compared. In the first approach, the folic acid analogue methotrexate was used as template and functional monomers capable of generating selective binding sites were searched in a miniaturized screening system based on binding assessment in the batch mode. Highest selectivity was seen using 2-vinylpyridine as functional monomer, which was confirmed in the chromatographic mode for a batch synthesized on a gram scale. However, the retentivity and selectivity of this phase were insufficient for anticipated applications. In a second approach, using methacrylic acid…

Determination of phenytoin in plasma by molecularly imprinted solid-phase extraction.

Abstract A molecularly imprinted polymer (MIP) using phenytoin as template and methacrylamide as the functional monomer was prepared. The selectivity was measured by comparing capacity factors of phenytoin and other structurally related compounds. The polymer was evaluated as a selective sorbent in molecularly imprinted solid-phase extraction (MISPE). Several washing solvents were tested to study their ability to disrupt the non-specific interactions occurring between the sample and the polymer matrix and the role of water in the recognition process was also investigated. It was shown that the key step of successful sample extraction is the right choice of the washing solvent. Plasma sample…

Grafting of Molecularly Imprinted Polymer Films on Silica Supports Containing Surface-Bound Free Radical Initiators

Silica particles containing surface-bound free radical initiators have been used as supports for the grafting of thin films of molecularly imprinted polymers (MIPs). This technique offers a means of fine-tuning the layer thickness for improved kinetic properties or enhanced capacity in chromatographic or sensor applications. Thus prepared MIPs imprinted with l-phenylalanine anilide, have been characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), elemental analysis, fluorescence microscopy, and scanning electron microscopy (SEM), providing evidence concerning the reproducibility in each step and the quantity and quality of the grafted…

Studies on the Process of Formation, Nature and Stability of Binding Sites in Molecularly Imprinted Polymers

AbstractIn Molecular Imprinting the nature of the templated binding sites and the mechanism of their formation are still poorly understood. For this reason our groups are carrying out fundamental studies concerning known imprinting protocols, with the primary aim of shedding light on the role of the template in the different steps of the polymerisation, from the formation of primary chains to the build-up of the porous structure. In this paper we report our initial results concerning copolymers of methacrylic acid (MAA) and ethyleneglycol dimethacrylate (EDMA) and their formation in presence or absence of the templates 9-ethyladenine, ametryn or terbutylazine. Monitoring the monomer disappe…

Molecularly imprinted composite materials via iniferter-modified supports

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…

Layer-by-Layer Grafting of Molecularly Imprinted Polymers via Iniferter Modified Supports

Development of a semiautomated procedure for the synthesis and evaluation of molecularly imprinted polymers applied to the search for functional monomers for phenytoin and nifedipine

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…

Molecularly imprinted polymers (MIPs) against uracils: Functional monomer design, monomer-template interactions in solution and MIP performance in chromatography

AbstractThe interaction of N1-substituted uracils (cyclohexyl (1) and benzyl (2)) with three polymerisable recognition elements, the novel monomers 9-(3/4-vinylbenzyl)adenine (3) and 2,6-diamino-9-(3/4-vinylbenzyl)purine (4) and the previously synthesised monomer 2,6-bis(acrylamido)pyridine (5), has been studied via1H NMR in deuterio-chloroform solution. MIPs against (2) have been prepared using each of the monomers and tested in the chromatographic mode. The effect of the number and type of hydrogen bonds formed between the templates and the functional monomers is reflected in the values of the apparent association constants obtained from the solution study and by the performance of the su…