Computational Simulation Of Molecularly Imprinted Polymers For Food Safety Dertection

Food safety is an important issue which is related to human health,and detection technology of various hazards in food is the foundation to guarantee food safety.In order to ensure food safety in our country,it is essential to develop accurate,efficient and sensitive detection method to detect illegal additives,pesticide residues and antibiotic residues in food,so as to solve problems like complex matrix,time-consuming pretreatments and wide interference.Molecularly imprinted polymers(MIPs)have advantages of strong affinity and high selectivity to the target compounds,anti-interference and good stability,also they are easy to keep and reusable.So MIPs are getting more and more widely applied in solid phase extraction,biomimetic sensors,chromatographic separation and other areas of food safety detection.As a screening method of synthesizing MIPs,molecular simulation can replace part of conventional experiment,reducing test times,consumption of reagents and artificial greatly,which can improve the development efficiency of molecularly imprinted polymers with great affinity and selectivity.This study selected representative illegal additives in food,pesticides,antibiotics--DEHP,pirimicarb,chloramphenicol as the research objects.Using Gaussian 09 software and the theory of quantum chemistry,through the computer molecular simulation of these particular molecular imprinting systems,theoretical predictions and partial experimental verification have been carried on.The results of the study are as follows:1.With DEHP as template molecule,MAA,AA and AN as functional monomers,using PM3 semi-empirical algorithms,the geometric configuration was optimized,the IR spectrum was analyzed,and got the most stable structure with no imaginary frequency and lowest energy;calculated the Mulliken charge of DEHP and different functional monomers,inferred the the possible active sites between them;optimized the complex,the binding energy was calculated,the binding energy of DEHP with MAA and AN is lowest as 19.31 kJ mol-1 and 17.71 kJ mol-1 respectively,and their structures are the most stable;experiment verifies that adsorption values of M-MAA(105 ?mol g-1)and M-AN(110 ?mol g-1)are significantly higher than that of M-AA(40 gmol g-1).So when MAA or AN is selected as a functional monomer,the MIPs adsorption capacity will be higher.The experimental results are in conformity with molecular simulation results.2.With pirimicarb as template molecule,MAA,AA,MMA and AN as functional monomers,using DFT/B31YP/6-31+ G(d,p)algorithm,the geometric configuration was optimized,frequency was analyzed,and got the most stable structure with no imaginary frequency and lowest energy;calculated the ESP of pirimicarb and different functional monomers,inferred the active sites that may occur between them;optimized the complex,calculated the binding energy,the binding energy of pirimicarb and MAA is minimum as 38.06 kJ mol-1,whose structure is the most stable;Experiment verifies that adsorption value of M-AA(16.55 mg g-1)is higher than that of M-AN(14.73 mg g-1),so MAA as a functional monomer means higher adsorption capacity.The experimental results are in conformity with molecular simulation results.3.With chloramphenicol as template molecule,MAA as functional monomer,using PM3 semi-empirical algorithms,their geometric configurations and active sites were simulated and analyzed,and the binding energy of chloramphenicol and MAA with imprinting ratio of 1:1,1:2 and 1:3 was calculated.Among those three complexes,the binding energy of chloramphenicol and MAA with ratio of 1:3 is minimum as 68.008 kJ mol-1,with the maximum effective active sites,the largest hydrogen bond strength and the most stable structure.Using computational simulation to study molecularly imprinted system of illegal additives,pesticides and antibiotics in food,can not only provide theoretical and experimental guidance to improve molecular imprinting technology,but also accelerate the molecular imprinting technology research and application in the field of food safety rapid detection,providing support for China's food safety guarantee.