Preparation And Adsorption Properties Of Aristolochic Acid I Molecularly Imprinted Polymer Via RAFT Precipitation Polymerization

The reduction product of Aristolochic acid I(AA I) in vivo is combined with DNA via irreversible binding, which triggered the famous disease as "aristolochic acid nephropathy".Therefore, most herbal products containing AA I were baned to sell on shelves at home and abroad in recent years, which not only has great insidious influences on Traditional C hinese Medicine industry in C hina, but also created the world problem of "aristolochic acid nephropathy". Some scholars do a lot of researchs to remove the toxic subatance from herbal products, which led some important advancements and achievemants. Unfortunately, there still have important practical significance, scientific significance and challenges to efficiently remove the toxic compound AA I from herbal products containing AA I. In this paper, we used AA I as the template molecule to construct molecularly imprinted polymer(MIP) and we also study its adsorption properties.Finally, we used the MIP to remove the AA I from the ethanol extract of Aristolochia manshuriensis Kom.. The results are as follows:1. MS software was carried to simulate and optimizate the functional monomer and solvent, the results showed the acrylic acid(AA), DMF-water was the best functional monomer and solvent respectively. The differential Ultraviolet–visible spectroscopy was used to study the hydrogen bond between AA I and AA in DMF- aqueous solution, which the results of experiment showed the combined ratio was AAI: AA = 1: 4.2. AA I as template molecule, AA as functional monomer, EGDMA as crosslinker,AIBN as a chain initiator, CTP as a chain transfer agent, 80%(g/g) DMF-aqueous solution as the porogen, MIP was prepared by RAFT polymerazation with the yield of 63.42%, while,non-imprinted polymer molecule( NIP) with the yield of 79.22%.3. Infrared spectroscopy, solid Ultraviolet–visible spectroscopy, nitrogen adsorption method and laser particle size method were carried to characterize the composition, structure and particle size of MIP and NIP. The results showed both MIP and NIP have the same composition and the similar structures, which mean we had successfully constructed MIP via RAFT polymerazation. In addition, MIP, NIP specific surface area were 19.524, 10.617 m2?g-1 respectively, meanwhile the average pore diameter, were 2.454, 2.167 nm.4. The adsorption isotherm was carried to study the static adsorption behavior of MIP and NIP. The results demonstrate that the adsorption of MIP and NIP followed the Langmuir model at 0.002~0.01 mg? mL-1. The adsorption constants of Langmuir model are 232.45, 58.02 mL? mg-1 respectively, which supports the MIP had a stronger binding capacities to AA I than that of NIP and the MIP shows an appreciable selectivity to AAI; Scatchard model results show that there are only one class of adsorption methods, and the dissociation constant of MIP and NIP were respectively 8.9, 26.2 mg/L, which also prove that the MIP of AA I had higher specific adsorption capacity than that of NIP.5. The dynamic adsorption isotherm behavior of MIP and NIP(25 oC) was used to evaluate the specific adsorption capacity of MIP and NIP. The results testify the MIP follows the first order kinetics model(log(Qeq-Qt) =-0.160t+0.181,R2 = 0.993), while the NIP is in accord with the second-order model(t/Qt = 2.186t+3.745,R2 = 0.997). The dynamic adsorption isotherm behavior of MIP and NIP also demonstrate that the MIP of AA I had higher specific adsorption capacity than that of NIP.6. The dynamic adsorption experiments revealed that the adsorption capacity of MIP is almost not affected by temperature(20-50 oC). The specific selective adsorption experiments approved that the MIP expresses an excellent specific recognition ability to AA I. The recycling experiment testified that the MIP is recyclable.7. The HPLC method was used to determine the adsorption capacity of MIP toward AA I from the ethanol extract of Aristolochia manshuriensis Kom., the results showed that 25.0 mg of MIP can remove the AA I below the HPLC detection limit from 5.0 ml of ethanol extract(CAA I =0.0018 mg/mL) with the recovery of AAI to 41.70%.In conclusion, the MIP was successfully constructed via RAFT precipitation polymerization.The MIP shows an excellent selective adsorption to AA I and others satisfactory properties. It is expected to be applied to remove AA I from herba l products. In other words, the results of in this paper provides new ideas, new methods to remove toxic substance from herbal products.