Molecularly Imprinted Solid-phase Extraction Of Matrine From Radix Sophorae Tonkinensis

In 1940 Pauling first proposed the hypothesis of molecular imprinting technique (MIT).With recognition ability for the template molecule, molecularly imprinted polymer (MIP) is able to selectively extract analyte from complex samples and are growing of interest for their potential applications as advanced materials for solid-phase extraction.Molecularly imprinted solid-phase extraction (MISPE) presents the high specificity, selectivity and sensitivity of the molecular recognition mechanism, and the high resolving power of separation methods.It chooses highly selectivity adsorption resin as adsorption material not only pre-enrich the template molecule but also remove other compounds present in the complex samples.This technique is more rapid, economical,environment-friendly and simpler than the traditional liquid-liquid extraction.In this paper, a matrine (MAT) molecularly imprinted polymer (MIP) with special molecule recognition properties of matrine (MAT) was prepared by self-made water-solubility resin and matrine as template molecule.An equilibrium binding experiment was performed to investigate the binding ability to the template molecule.Some characters of the imprinted polymer, such as the optimum ratio of template/functional monomer (T/M), the effect of Ph on amount of adsorption and was also studied.The results indicated that the imprinted polymer had higher adsorption and good elution ability when T/M was 5mg/g.Scatchard analysis showed that only one kind of binding sites existed in the MAT-imprinted polymers with its dissociation constants estimated to be 3.31×10-4 mol 1-1(200-400 mesh(inch-1))and 6.83×10-4 mol 1-1 (over 400 mesh (inch-1)) depending on what mesh the MIPs were to be grounded.Appling the MIPs as a solid-phase extraction (SPE)sorbent to investigate the elution performance, meanwhile, adsorption methodelution effect, the optimum elution solvent, elution of residual were studied. At last applied MISPE to extracted matrine from Radix Sophorae Tonkinensis.The elution ability data showed that it could enhance the ability of adsorption when the sorbent resin was alkalined.Moderate polarity of acetone as the elution solvent was better than chloroform and water. Utilizing this MISPE as the separation medium, a crude extract of matrine from Radix Sophorae Tonkinensis was purified.The results showed that the MIPs had high selectivity for MAT and the contents of matrine obtained by MISPE was 1.4 times to that obtained by liquid-liquid extraction.