Preparation And Application Of Emodin Molecular Imprinting Polymers

A series of emodin imprinted polymers were prepared by molecular imprinting technology. The polymerization method, temperature, functional monomer and solvent were studied through the static assay and scatchard equation. The results showed that the polymers having a high adsorption and selectivity for emodin were prepared by using bulk polymerization at the condition of emodin as template molecular, acrylamide as the functional monomer, ethylene glycol dimethyl acrylate as the cross-linking agent, the molar ratio of template molecular and functional monomer was 1:4, the molar ratio of template molecules and cross-linking agent was 1:20, acetone as porogen and at the temperature of 60℃. The most apparent absorption capacity was 1127.53μmol/g, and the separation factor was 9.18. It was demonstrated that the surfacial holes of MIPs provided a good channel for the selective adsorption by scanning electron microscope. The chemical stability of MIPs was evaluated, and the results showed that MIPs were acid-resistant, alkali-resistant, organic solvents-resistant, and can be used in different circumstances.The separation of emodin from rhubarb and polygonum cuspistum by the impregnation method and ultrasound-assisted method had been researched. The optimum conditions were obtained by individual factors test and orthogonal test. The ultrasonic-assisted method had higher extraction efficiency than impregnation.Application of the MIPs on solid-phase extraction(SPE) to separate emodin from complicated samples (crude extracts of rhubarb and polygonum cuspistum) was examed. The influences of washing solvent, eluting solvent and flow rate were studied. The products were characterized by UV and IR. It showed that emodin can be enriched and separated effectively and it had a fairly good results.