乐果与氧化乐果在金/银核-壳粒子上的SERS研究

Surface Enhanced Raman Scattering of Dimethoate and Omethoate on Core-Shell Au/Ag Nanoparticle

联合红外、拉曼光谱及其在金/银核-壳粒子上的表面增强拉曼散射(SERS)光谱表征了乐果和氧化乐果两种乐果类似物,归属并分析了两乐果类似物中P=S与P=O的不同而引起的振动模式,峰位变化及其酸碱影响.振动光谱显示,ν(P=O),ν(P=S)分别在690,650cm-1附近,两分子结构中对应的ν(NH),νs(CH2),ν(C—O),ν(O=C—N)II,ν(S—CH2)振动峰位中差异显著,但νas(CH3),ν(P—O—C),ν(O=C—N)I,δ(CH3),ν(C—C),ν(C—C=O)则基本对应.在金/银核-壳粒子基底上,进一步探讨了两乐果类似物中各基团在不同浓度,pH值及酸、碱水解历程条件下的SERS变化规律,并运用SERS机理并结合TEM初步阐述了两乐果类似物在金/银核-壳粒子表面的吸附状态.

Two dimethoate analogues-dimethoate and omethoate, are characterized by vibrational spectroscopy-FT-Raman and FTIR, and surface enhanced Raman scattering （SERS） on the substrate of Au/Ag core-shell nanoparticle. The vibrational peaks are assigned, and the vibrational mode and peaks’ shift resulting from different inner structures P=S and P=O in molecules of two dimethoate analogues are also analyzed at acidic and basic conditions. From the vibrational spectra, these groups ν（NH）, νs（CH2）, ν（C—O）, ν（O=C—N） II, ν（S—CH2）, ν（P=O） and ν（P=S） in the analogues present notable different vibrational peaks, except for 690 cm-1 ν（P=O） and 650 cm-1 ν（P=S）, while the peaks of νas（CH3）, ν（P—O—C）, ν（O =C—N） I, δ（CH3）, ν（C—C）, ν（C—C=O） are almost corresponding. The relationships of concentrations, pH values and hydrolysis processes in acidic and basic condition, to dimethoate analogues’ SERS are further discussed, and the analogues’ adsorption status on the Au/Ag core-shell nanoparticle surface are also speculated with SERS mechanisms and TEM.