Organic-imprinting matrix

Organic Polymer matrix components for molecular imprinting Empirical data on analyte binding to different polymerizable mono- 45... 

There are two methods to prepare a cavity with a shape similar to a template molecule-by-molecular imprinting, as illustrated in Fig. 22.2a. Organic or inorganic polymer matrices are synthesized around the template molecule to form a conformal structure around the template. The template molecule is removed from the polymer matrix, resulting in the transfer of the shape of the template molecule in the polymer matrix, which then acts as a selective adsorption site for molecules with a shape similar to the template. 

Fig. 22.2 Schematic procedures for the synthesis of molecularly imprinted catalysts (a) with organic binding sites Right triangle, Filled circle, Filled square) (e.g., NH, NH, OH, and COOH) on the wall of a polymer matrix and (b) using a metal complex coordinating a template ligand...

Polymerised preformed [(N,N -dimethyl-l,2-diphenylethane diamine)2Rh] complex allows us to obtain enantioselective material. We have then shown that it is possible to imprint an optically pure template into the rhodium-organic matrix and to use the heterogeneous catalyst in asymmetric catalysis with an obvious template effect. The study of yield versus conversion graphs has shown that the mechanism occurs via two parallel reactions on the same site without any inter-conversion of the final products. Adjusting the cross-linker ratio at 50/50 allows us to find a compromise between activity and selectivity. Phenyl ethyl ketone (propiophenone) was reduced quantitatively in 2 days to (R)-l-phenyl propanol with 7tf% enantiomeric excess We have then shown that the imprinting effect is obvious for molecules related in structure to the template (propiophenone, 4 -trifluoromethyl acetophenone). It is not efficient if the structure of the substrate is too different to that of the template. 

Based on their chemical and mechanical properties, imprinted materials were applied in a variety of techniques. Solid phase extraction (SPE) has become a common method used to concentrate analytes in order to improve their detection. Among the advantages of SPE nuterial based on MIPs were specificity and compatibility with both aqueous and organic solvents. MIPs as SPE matrixes were useftil for sample preconcentration and purification. The superior performance of MIPs SPE for routine analysis was demonstrated on a variety of compounds such as drug and pesticides. ... 

Several extraction techniques have been reported in the literature for the analysis of sulfonamides. Because of their polar nature, sulfonamides are readily extracted by organic solvents ° ° the most commonly used are acetonitrile.Other organic solvents used for analyte extraction and protein precipitation include dichloromethane, " acetone, ethanol, chloroform, and ethyl acetate, " which are often used either alone or in conjunction with one another. Other techniques used for protein precipitation include the use of acids such as perchloric or formic and the use of basic buffers such as potassium hydrogen phosphate and ammonium sulfate. In the case of honey, the use of acids such as trichloroacetic, " " hydrochloric, and phosphoric is necessary for hydrolysis, releasing carbohydrate-bound sulfonamide residues. Other extraction techniques reported in the literature include the use of pressurized liquid extractions, " matrix solid-phase dispersion, and magnetic molec-ularly imprinted polymers. Of additional note, several authors have observed that analyte recoveries were largely... 

Another concept of chiral molecular imprinting was developed by Wulff and colleagues who used an organic polymer network as a matrix instead... 

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