乐果的振动光谱及其在金/银核-壳复合粒子表面的SERS研究

联合FTIR,FT-拉曼表征了乐果的振动光谱,获得了固态及不同酸碱条件下饱和液态乐果的振动特征信息;以金/银核-壳复合粒子为基底,获得了乐果在酸碱条件下一系列浓度的表面增强拉曼散射(SERS)光谱,考察了乐果分子在该基底表面的吸附状态及其酸碱影响,推测了乐果与金/银核-壳复合粒子作用机理;结果表明:νas(NH),νas(CH3),ν(O=C-N),τ(O=C-N),ν(P—O),ν(P S),ν(C—C),δ(P—O—C)为乐果分子特征振动;酸、碱条件下,在1.0×10-3mol.L-1为乐果与基底作用的最佳浓度;乐果主要以P—O—C,O=C-C,(S—CH2),P=S,CH3与金/银核-壳复合粒子基底相作用,探讨了酸碱条件下磷酸酯键不同离解历程对吸附的影响。为研究有机磷农药的形态变化提供有益参考。

The study of dimethoate by means of vibrational and surface enhanced Raman spectroscopy on Au/Ag core-shell nanoparticles

The vibrational structure of dimethoate, with its solid state and saturated solutions at acidic and basic conditions, was characterized with combination of means of FTIR and FT-Raman vibrational spectroscopy technology, and the comprehensive information about the dimethoate molecular groups' vibrational features was obtained. The surface enhanced Raman scattering (SERS) spectra of dimethoate at different concentrations with different acidic and basic conditions, and adsorbed on the substrate's surface of the core-shell Au/Ag nanoparticles, were also obtained. The adsorption states of dimethoate's molecule on the substrate's surface of the core-shell Au/Ag nanoparticles and the effects by the different acid-base conditions were investigated, with speculation of the adsorption mechanism. From the results, v(as)(NH), v(as)(CH3), v(O=C-N), tau(O=C-N), v(P-O), v(P=S), v(C-C) and delta(P-O-C) are the characteristic peaks of inner dimethoate structure's vibrations; and the concentration range in which dimethoate could interact with core-shell Au/Ag nanoparticles fully is about 1.0 x 10(-3) mol * L(-1) both in acidic and basic conditions. Dimethoate's molecule interacts with SERS' substrate surface mainly through P-O-C, O=C-C, (S-CH2), P=S, and CH3 structures; and the effects of dimethoate's hydrolysis path in acidic and basic conditions on the adsorption are discussed, which give some good references for the research of organophosphorus pesticides' transformations in different environmental systems.