Studies On Preparation And Application Of Indole-3-Acetic Acid Molecularly Imprinted Polymer

Indole 3-acetic acid (IAA) is an important plant hormones in plants. Efficient extraction and accurate determination of IAA from plant samples has very important significance for the study of its regulation in plant life. In this paper, molecular imprinting technology was conducted to prepare the molecularly imprinted polymers (MIP) with a specific selective adsorption on the template molecule IAA, by selecting the appropriate monomers and porogenic agents, optimizing preparation conditions, characterization analysis of imprinted polymer and solid phase extraction applied in Arabidopsis plant samples. The results are as follows:In the preparation of IAA molecularly imprinted polymers (IAA-MIP), the establishment of reaction system is very important for improving MIP affinity and selectivity. The results of dissolution experiment with 3 kinds of porogenic agents toluene, methanol and acetonitrile showed that polymerization effect was the best using acetonitrile as porogenic agents. The final establishment conditions of the bulk polymerization to prepare IAA molecularly imprinted polymers were using IAA as the template, methacrylic acid as functional monomer, acetonitrile as porogenic agent, template and functional monomer ratio as 1:8, dark polymerization of 24 h at 50℃ of water bath.The infrared spectroscopy analysis of IAA-MIP indicated that the template molecule IAA was hydrogen bonded to the cavity of imprinted polymers. The adsorption isotherms and Scatchard analysis showed that the IAA imprinted polymers had higher affinity to IAA than that of non-imprinted polymers (NIP). There were two kinds of binding mode between the imprinted polymers and IAA template molecule, the dissociation constants were KD1=1.04×10-6mol/L and KD2=9.23×10-6 mol/L, the maximum apparent binding sites was BMax1=0.10 μmol/g and BMax2=0.28 μmol/g respectively.The results of experiments of solid phase extraction from plant samples showed that the synthesized molecularly imprinted polymers had specific adsorption capacity for IAA, and the recovery of IAA reached 62.64%.