Enantiomeric resolution of amino acid derivatives on molecularly imprinted polymers as monitored by potentiometric measurements

Potentiometric measurements have been applied to the detection of enantiomeric separations on molecularly imprinted polymers. A flow-through column electrode, based on the use of polymers imprinted against L-phenylalanine anilide, is described. The electrode consisted of a glass column in which the polymer was packed and where the end frits constituted the electrodes. The flow stream potential across the column can be continuously recorded as solvent is pumped through the system. The column resolved the enantiomers of phenylalanine anilide as detected by both UV absorption and potentiometric measurements and the recorded signals could be correlated with the concentration of phenylalanine anilide. The calibration graphs obtained for the UV absorption of phenylalanine anilide were linear over the concentration range investigated, whereas the potentiometric signal was shown to be exponentially linear with concentration. The application of molecular imprints to the preparation of supports suitable for chromatographic separations of enantiomers and for the preparation of specific electrodes is discussed.     

Applications of molecularly imprinted materials as selective adsorbents: Emphasis on enzymatic equilibrium shifting and library screening

Summary Molecular imprinting is an attractive method for producing highly selective adsorbents, and several new and potentially useful applications based on molecularly imprinted polymers (MIPs) have been described in recent years. In this article, we highlight some of the areas where these materials have found application, and also describe some new fields of application where the selectivities of imprinted materials can be gainfully employed, for example as binding matrices in the screening of combinatorial libraries, and as auxiliary agents in enzymatic syntheses. Presented at: Affinity Chromatography Conference, Cambridge, UK, July 1–3, 1997.     

Magnetic microspheres for targeting of drugs

Magnetic microspheres were prepared from starch. The microspheres could be crosslinked with various agents, and drugs could be entrapped adsorbed, or covalently coupled to the microspheres.     

Studies towards a tailor-made catalyst for the Diels-Alder reaction using the technique of molecular imprinting

A tailor-made catalytically active polymer catalyzing the bimolecular Diels-Alder reaction is described. Kinetic studies carried out in acetonitrile at 82°C show a 270-fold rate acceleration (k_cat/k_uncat) for the Diels-Alder reaction between tetrachlorothiophene dioxide and maleic anhydride. The imprinted polymer induces Michaelis-Menten kinetics, with an apparent K_m of 42.5 mM and an apparent k_cat of 3.82 × 10⁻² min⁻¹, respectively. Substrate selectivity, accessible binding site analysis, dissociation constant determination, and inhibition study were also performed.