Molecular Dynamics Simulation Of Chlorpyrifos And Its Main Metabolite 3,5,6-TCP Adsorption On A Silicon(110) Crystal Plane

As the problem of environmental pollution caused by pesticide residues becomes increasingly severe,the evaluation of whether the amount of pesticide application complies with regulations and whether the pesticide residue in the environment is below the limit value is becoming more and more important.At the same time,this also puts forward higher requirements for the development of pesticide detection technology.In this paper,with the help of the emerging research method of molecular dynamics simulation,the modeling of the adsorption system is used to observe more intuitively the interaction mode and molecular dynamics process of the pesticide molecule in the process of detecting the pesticide Chlorpyrifos on a single crystal silicon surface,which deepens the understanding of the adsorption mechanism between the pesticide molecule and the silicon crystal surface in the process of detecting Chlorpyrifos using silicon microsensors.Based on the simulation results obtained from this model,the actual concentration of pesticides can be effectively predicted.The specific research content is as follows:Firstly,based on the principles related to molecular dynamics,a stable molecular model of chlorpyrifos and the adsorption substrate crystal silicon(110)surface were constructed using Materials Studio software,and the adsorption of chlorpyrifos on the crystal silicon(110)plane under vacuum was simulated.The mechanism of interaction between chlorpyrifos molecules and the crystal silicon(110)surface was investigated by means of atomic proximity contact calculations and comparative analysis of interaction energies in the adsorption configuration.The adsorption behavior between chlorpyrifos molecules and the crystal silicon(110)surface is mainly influenced by van der Waals and electrostatic forces,and the adsorption of chlorpyrifos molecules on the crystal silicon(110)surface decreases with increasing temperature.Secondly,a rational conformation was constructed to simulate the adsorption of chlorpyrifos molecules and the main metabolite 3,5,6-TCP on the crystal silicon(110)surface in an aqueous environment,and the adsorption behavior of chlorpyrifos molecules and 3,5,6TCP molecules on the crystal silicon(110)surface was investigated based on the adsorption conformation,molecular MSD curves and molecular interaction energy calculations.The adsorption behavior of chlorpyrifos molecules and 3,5,6-TCP molecules on the crystal silicon(110)surface was investigated and the adsorption behavior of chlorpyrifos molecules and 3,5,6-TCP molecules on the crystal silicon(110)surface in aqueous environment was found to decrease with increasing temperature.In order to further investigate the adsorption of multiple chlorpyrifos molecules and multiple 3,5,6-TCP molecules on the crystal silicon(110)surface in an aqueous environment,new adsorption configurations were constructed for simulation studies,revealing a link between the results obtained from the use of silicon microsensors for the detection of pesticide chlorpyrifos or 3,5,6-TCP concentrations and the actual concentrations of pesticide chlorpyrifos or toxic metabolite 3,5,6-TCP in the monitored area.The association between the actual concentrations of chlorpyrifos or 3,5,6-TCP in the monitored area.The results show that the results of the silica microsensor for chlorpyrifos in water at 288,298 K and 308 K are 100%,66.67%and 88.89%of the actual chlorpyrifos concentration in the area,respectively,and require different concentration limits,namely 0.030,0.020 mg·L-1,and 0.027 mg·L-1,respectively,the results for 3,5,6-TCP were 100%,88.89%and 77.78%of the actual 3,5,6-TCP concentrations in the area,respectively.Finally,molecular dynamics simulations of chlorpyrifos molecules and 3,5,6-TCP on the crystal silicon(110)surface were carried out by creating different acidic and alkaline simulated environments.The adsorption of chlorpyrifos molecules was stronger in the weak acid,weak base,medium base and strong base environments than in the neutral environment,while the adsorption of chlorpyrifos molecules in the medium acid environment was not significantly different from that in the neutral environment,and the adsorption of chlorpyrifos molecules in the strong acid environment was slightly weaker than that in the neutral environment.The adsorption of chlorpyrifos molecules on the crystal silicon(110)surface was found to be greater than that on the crystal silicon(110)surface in the acidic environment when the simulated conditions were certain.