scholarly journals Surface-Enhanced Raman Scattering Detection of Fipronil Pesticide Adsorbed on Silver Nanoparticles

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1355 ◽  
Author(s):  
Nguyễn Hoàng Ly ◽  
Thi Ha Nguyen ◽  
Ngô Đình Nghi ◽  
Young-Han Kim ◽  
Sang-Woo Joo

This work presents a surface-enhanced Raman scattering (SERS) and density functional theory (DFT) study of a fipronil adsorbed on colloidal silver nanoparticles (AgNPs). A standard curve was established to quantify fipronil within a range of 0.0001–0.1 ppm (r2 ≥ 0.985), relying on the unique fipronil Raman shift at ~2236 cm−1 adsorbed on AgNPs. DFT calculations suggest that the nitrile moiety (C≡N) binding should be slightly more favorable, by 1.92 kcal/mol, than those of the nitrogen atom of the pyrazole in fipronil and Ag6 atom clusters. The characteristic peaks of the SERS spectrum were identified, and both the calculated vibrational wavenumbers and the Raman intensity pattern were considered. The vibrational spectra of fipronil were obtained from the potential energy distribution (PED) analysis and selective Raman band enhancement.

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1211 ◽  
Author(s):  
Isabel López-Tocón ◽  
Samuel Valdivia ◽  
Juan Soto ◽  
Juan Carlos Otero ◽  
Francesco Muniz-Miranda ◽  
...  

A Surface-Enhanced Raman Scattering (SERS) spectrum of 4-cyanopyridine (4CNPy) was recorded on silver plasmonic nanoparticles and analyzed by using Density Functional Theory (DFT) calculations. Two simple molecular models of the metal–4CNPy surface complex with a single silver cation or with a neutral dimer (Ag+–4CNPy, Ag2–4CNPy), linked through the two possible interacting sites of 4CNPy (aromatic nitrogen, N, and nitrile group, CN), were considered. The calculated vibrational wavenumbers and intensities of the adsorbate and the isolated species are compared with the experimental Raman and SERS results. The analysis of the DFT predictions and the experimental data indicates that 4CNPy adsorbs preferentially on neutral/charged active sites of the silver nanoparticles through the nitrogen atom of the aromatic ring with a perpendicular orientation.


2013 ◽  
Vol 395-396 ◽  
pp. 158-161 ◽  
Author(s):  
Yu Dong Lu ◽  
Xia Xia Chen ◽  
Li Hui Chen

Silver Nanoparticles has been prepared using the complex of carboxymethyl cellulose (CMC) and Polyvinylpyrrolidone (PVP) as a template and used as SERS substrate. The effect of the ratio of CMC to PVP on silver nanoparticles was discussed. Silver Nanoparticles were characterized by UV-visible spectroscopy, transmission electron microscopy and Raman spectroscopy. The results show that the ratio of CMC to PVP plays a crucial role in the performance of nanoparticles. TEM studies reveal that particles are mostly near-spherical in shape with an average size of 60-70 nm. The SERS enhancement of these silver nanoparticles was tested by using Rhodamine 6G (R6G) as a probe molecule. The silver nanoparticles prepared with the complex of CMC and PVP as a template have been shown to provide strong enhancements in the SERS spectrum of R6G. Keywords: Carboxymethyl cellulose; Polyvinylpyrrolidone; Surface-enhanced Raman scattering; silver; Template


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