Preparation And Application Of Molecularly Imprinted Polymers Based On TNT Detection

In recent years,international explosions have become more frequent and the rapid detection of explosives has become an urgent technical problem.However,the existing detection methods have some certain deficiencies.Molecular Imprinting Technology has emerged as the times require.Its stable,specific and convenient characteristics provide a new solution for the detection and identification of explosives.In this paper,Molecularly Imprinted Polymers?MIPs?and Magnetic Molecularly Imprinted Polymers?MMIPs?were synthesized using common monomer explosive TNT as template molecules and electrochemical sensors were prepared.The adsorption properties of MIPs were explored.The specific research content is as follows:?1?MIPs were prepared by emulsion polymerization for the detection of explosives TNT.Ultraviolet spectra showed that there is an interaction between TNT and MAA,which is helpful to form MIPs with stable structure and strong affinity.The prepared MIPs have a good morphology and a diameter of about 200nm at 30ml of solvent,12mg of emulsifier and 250rpm stirring rate.Adsorption experiments showed that the adsorption capacity of MIPs to TNT increased with the increase of initial TNT concentration.After 140 minutes MIPs reached 95%of the maximum adsorption capacity.The separation constant of MIPs to TNT was more than 350ml/g and the selectivity coefficients of MIPs to RDX and DNT were more than 4.4,showing better specific adsorption performance.?2?MMIPs were prepared by mini-emulsion polymerization using modified Fe₃O₄particles as carrier.The prepared polymers were characterized by infrared,thermogravimetric to verify the successful preparation of the polymers.The adsorption experiments showed that with the increase of initial template co ncentration,the adsorption capacity of MMIPs increased and the adsorption process was dominated by monolayer adsorption.After 80 minutes MIPs reached 83%of the maximum adsorption capacity and accorded with pseudo-second-order kinetics adsorption.The adsorption capacity of MMIPs on TNT was 2.56 times of DNT and 2.88 times of RDX,respectively,which showed that the adsorption capacity of MMIPs on TNT was better than that of DNT and RDX.?3?The MIPs prepared by emulsion polymerization was dispersed in t he solvent and the electrochemical sensor was prepared by surface coating method.Scanning electron microscopy?the potassium ferricyanide probe experiment and the response curve of TNT were used to verify the successful preparation of the electrochemical sensor.The detection limit experiment,enrichment time experiment and selective adsorption experiment show ed that the sensor can reach 94%of the maximum current value after enrichment for 3 minutes and achieve adsorption equilibrium within 5 minutes.The TNT concentration had a good linear relationship with peak current in the range of 0.1mg/ml⁵mg/ml and the detection limit was 0.06mg/ml.The current response of MIPs sensor to TNT was 3.13 and 3.27 times that of DNT and RDX respectively,which showed strong specificity.The work of the thesis provides a new solution for the detection of explosives.A preliminary exploration was made on the parameters such as solvent capacity and stirring rate for preparing TNT polymer.It serves as a good reference for the trace detection of TNT.