| Molecular imprinting technology has been a hot issue to investigate because which can provide the polymers that have specialized recognition and selectivity properties to template molecule. In this technique, functional monomers and crosslinkers are polymerized around template molecules, which is followed by extracting the template molecule from the polymer to leave a template-fitted cavities inside the polymers, molecular imprinted polymers(MIPs) are obtained. As its excellent identification and selectivity they have been widely used in environmental, pharmaceutical, chemical, food hygiene, and so on. In recent years, a new and high efficient isolation method of the active ingredient from natural products is receiving more and more attention.1. The apigenin molecularly imprinted polymer was prepared by bulk polymerization. Optimizing its preparation process conditions, the results showed that an apigenin (API) molecularly imprinted polymer had higher selectivity which was prepared by bulk polymerization using apigenin as template,α-methacrylic acid (MAA) as functional monomers, ethylene glycol dimethacrylate (EDMA) as a crosslinking agent, tetrahydrofuran (THF) and acetone (V/V, 8:2) as porogenic solvents. The optimized ratio was determined be n(API):n(MAA):n(EDMA)=1:8:70 by investigated the effects of different concentrations of functional monomers and crosslinker on the MTP's recognition properties. Equilibrium binding experiment was used to investigate the adsorption dynamics, the thermodynamics and the substrate selectivity of apigenin. The scatchard analysis showed that two classes of binding sites existed in the apigenin imprinted polymers, with their with their KD and Qmax estimated to be 6.60×10-5, 1.74×10-4mol/L and 12.90, 28.30umol/g, respectively. The law of dynamics for the adsorption can be described by lagergren rate equation, the adsorption velocity increases with temperaturs. The adsorption isotherm could be correlated with Freundlich isotherm equation, and high temperature was good for the adsorption, and the spontaneous adsorption was a decalescence and increasing entropy process, the process of adsorption was mainly physical adsorption.2. The parsley and local celery leaves and petioles were extracted by methanol. The content of apigenin from its extraction were determined by HPLC. The results showed that the content of apigenin in parsley leaves and petioles were 8.635mg/100g,1.348mg/100g respectively, the content of apigenin in local celery leaves and petioles were 1.734mg/100g,0.567mg/100g respectively. To study the leaves of parsley, comparing reflux extraction, ultrasonic extraction, soxhlet extraction of different extraction methods on the content of apigenin. The results indicated that the content of apigenin which was extracted from parsley leaves by ultrasonic extraction was 9.316mg/100g. The efficiency of ultrasonic extraction was significantly higher than the other two kinds of methods.3. The molecular imprinting technique and solid-phase extraction (SPE) techniques were combined to extract and concentrate the apigenin from celery leaves extracts. The sample was uploaded and then the column was cleaned up with ethanol-water (1:1, V/V) solution and the apigenin was eluted with ethanol solution; such that the purity of apigenin could be increased from 0.26% to 91.89% and its recovery was about 91.23%. |
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