Preparation Of Molecularly Imprinted Polymers Based On Diles-Alder Reaction And Electrochemical Sensing Analysis

In this paper,Diels-Alder(DA)reaction was used for the preparation of molecularly imprinted polymers(MIP),and the obtained MIP have the characteristics of temperature sensitivity and specific recognition.To design a synthetic route that using silica gel as carrier,the modified?-CD as functional monomer,after the crosslinking polymerization,two kinds of new structure molecularly imprinted polymers were obtained to realize intelligent temperature control of imprinting of IAA and EC.DA-MIP(40)and DA-MIPII were synthesized by the reaction of Diels-Alder(DA)with diene,which can realize the intelligent control of template molecules.1.MIP(40)that have special absorbtion of IAA was characterized by FT-IR,CP/MAS ¹³C-NMR and SEM.The experimental results showed that the molecularly imprinted polymer was successfully prepared.The thermal property were tested by DSC and TG,Thermal performance showed that the DA key was successfully added.Adsorption performance and adsorption properties of the products were detected by adsorption experiment,The adsorption experiment showed that the imprinted factor(?)of MIP(40)of IAA is 3.44,the select factor(?)is 2.45,the?of DA-MIP(40)of IAA is 1.17,?is 0.17,it shows that 60?DA reaction makes the MIP(40)imprinting weakened.140?reaction of the preparation of r DA-MIP(40),the?of IAA is 3.19,?is 2.19,The result shows that the r DA reaction made the product specific adsorption performance restored to a certain extent,and showed good temperature sensitivity.epetitive adsorption experiment showed that the recovery rate was 84%,Thermal cycle test showed that the recovery rate of MIP(40)was 82%.2.MIPII that have special absorbtion of EC was characterized by FT-IR,CP/MAS ¹³C-NMR and SEM.The results showed that the DA bond was successfully introduced into the two kinds of target products,and the formation of the new type of imprinted polymers with thermal reversibility were achieved.The heat sensitive property were tested by DSC and TG,The results showed that MIP?and DA-MIP?have good thermal properties,and their temperature sensitivity were good,the reverse reaction temperature of DA-MIPII is about 130?.Analysis and comparison of molecular recognition and specificity of MIP II and its DA products and inverse DA products by adsorption experiment.The imprinted factor(?)of MIP?of EC is 6.2,the select factor(?)is 5.2;the?of r DA-MIP?of EC is 5.0,the?is 4.0.That is DA-MIP?does not show the role of identification of template molecule at low temperature(60?),but display specific identification at high temperature(130?),its temperature control was affected by environmental stimuli.Repetitive adsorption experiment showed that the recovery rate of MIP?was 89%.Three thermal cycle test showed that the recovery rate of MIP?was 78%.The binding characteristics of MIPII and its DA binding sites were model analyzed,Scatchard model was used to analyze the adsorption of MIPII on EC and in the low concentration range,the binding constant K_a1=0.0033 L·mmol^-1,the saturation binding site number Q_max1=663.64 mmol·g^-1;in the high concentration range,the binding constant K_a2=0.001 L·mmol^-1,the saturation binding site number Q_max2=1150 mmol·g^-1;The r DA-MIP?on EC and in the low concentration range,the binding constant K_a3=0.0013 L·mmol^-1,the saturation binding site number Q_max3=776.92 mmol·g^-1;in the high concentration range,the binding constant K_a4=0.00057 L·mmol^-1,the saturation binding site number Q_max4=1298.25 mmol·g^-1;The two above were all existed specific binding sites and nonspecific binding sites.Langmuir model was also used to simulate the adsorption performance,and the results showed that the Langmuir model showed better binding characteristics.3.MIP?and its DA products were used to prepare five kinds of electrodes,The characterization of CV and FRA showed that the electrodes were successfully prepared,and the adsorption performance and specific properties of the electrode were detected by DPV,and the adsorption equilibrium were reached at about 15 min.The maximum response current of MIPII-GE was 2.5 times of NMIPII-GE,2.0 times of DA-MIPII-GE,and 2.7 times of bare-GE.The maximum response current of r DA-MIPII-GE was 2.2 times of NMIPII-GE,1.7 times of DA-MIPII,and 2.4 times of bare-GE.The results showed that both MIP-GE and DA-MIPII-GE had better selectivity.Imprinting rate and template molecule is proportional to the concentration,in the range of EC concentration less than 1.0 mmol·L^-1,imprinting rate increased faster,showed good linear relationship;when the concentration in the range of1.0 mmol·L^-1?2.0 mmol·L^-1MIP-GE on the template molecule imprinting rake ratio decreases.The two have good adsorption properties and specific properties.