有机磷类农药的密度泛函理论计算及拉曼光谱研究

Density Functional Theory Calculation and Raman Spectroscopy Studies of Organophosphorus Pesticides

有机磷类农药常被用于防治植物病、虫、害,但对人、畜的急性毒性很强,能抑制乙酰胆碱酯酶。三种有机磷类农药分子(乐果、敌百虫和伏杀硫磷)的分子构型用GaussView3.07构造,理论计算采用密度泛函理论(density functional theory,DFT)的B3LYP/6-31G(d,p)基组,并将实验拉曼光谱、理论计算拉曼光谱和表面增强拉曼光谱(SERS)进行比较。结果表明,三种有机磷类农药分子的实验值与理论方法计算值具有很好的匹配性,并对三种有机磷类农药分子(乐果、敌百虫和伏杀硫磷)在400~1 800cm-1范围内的振动频率进行了全面地归属,找到了这三种有机磷类农药的特征峰。有机磷类农药分子的振动峰中会出现相近的波数,P—O基团引起的波数在1 140~1 320cm-1之间,PS的伸缩振动的谱带在535~750cm-1范围,含有P—O—C基团的有机磷类农药在920~1 088cm-1范围产生一个谱带。对比分析三种农药的实验拉曼光谱和表面增强拉曼光谱,找到了这三种有机磷农药分子各自主要的表面增强拉曼特征峰,这些表明利用SERS技术可以用来鉴定有机磷农药。研究结果为有机磷农药的定性定量分析提供了理论基础。

Organophosphorus pesticides were often used for prevention and control disease and insect of plant,and are acute toxic to human and livestock by anti-ache activity.The molecular geometry of three organophosphorus pesticides（dimethoate,trichlorfon and phosalone）were constructed on Gauss View3.07,and Density functional theory（DFT）was used to optimize and calculate the vibrational wavenumbers of three organophosphorus pesticides by B3 LYP hybrid functional and 6-31G（d,p）basis set.The experimental spectra of three organophosphorus pesticides were compared with the theoretically calculated spectra and Surface-enhanced Raman Scattering spectra（SERS）.The results indicated that the experimental spectra and theoretically calculated spectra of three organophosphorus pesticides have a very good match.The Raman peaks of three organophosphorus pesticides were roundly assigned between the range of 4001 800cm-1,and the characteristics peaks of three organophosphorus pesticides were found.The Raman vibration peak of organophosphorus pesticide may appear similar characteristic peak.The pesticide contained P—O is between 1 140 and 1 320 c m-1,the pesticide contained P S is in the range 535750cm-1,and the organophosphorus pesticide contained P—O—C is n the range 9201 088cm-1.The different characteristic peaks of three pesticides were found by the contrast of the surface enhanced Raman spectra.This shows that the SERS method can be used to identify the organophosphorus pesticide.The results can furnish a theoretical support for qualitative and quantitative analysis of organophosphorus pesticide.