scholarly journals SERS approach for Zn(II) detection in contaminated soil

2011 ◽  
Vol 9 (3) ◽  
pp. 410-414 ◽  
Author(s):  
László Szabó ◽  
Loredana Leopold ◽  
Bogdan Cozar ◽  
Nicolae Leopold ◽  
Krisztian Herman ◽  
...  
Keyword(s):  
Contaminated Soil ◽  
Metal Ion ◽  
Density Functional ◽  
Soil Extract ◽  
Sers Spectrum ◽  
Industrialized Countries ◽  
Soil Extracts ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

AbstractSoil contamination by metals is a common problem encountered in many industrialized countries. In this work we present a new approach for heavy metals detection by using surface-enhanced Raman scattering (SERS) spectroscopy. Zn(II) can be clearly determined by SERS in contaminated soil by using 4-(2-pyridylazo) resorcinol (PAR) as chelating molecule for the metal ion. The SERS spectra of PAR, of its metal chelates and of the soil extract-PAR mixture were recorded using a hydroxylamine reduced silver colloid. An excellent match of the PAR-contaminated soil extracts SERS spectrum to the Zn(PAR)2 SERS spectrum can be observed, demonstrating the presence of Zn(II) in the soil probes. Density functional theory (DFT) based calculations were also performed for a reliable assignment of SERS spectra.

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
Keyword(s):  
Silver Nanoparticles ◽  
Raman Scattering ◽  
Density Functional ◽  
Surface Enhanced Raman Scattering ◽  
Potential Energy Distribution ◽  
Raman Shift ◽  
Sers Spectrum ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

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.

scholarly journals A DFT Approach to the Surface-Enhanced Raman Scattering of 4-Cyanopyridine Adsorbed on Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1211 ◽  
Author(s):  
Isabel López-Tocón ◽  
Samuel Valdivia ◽  
Juan Soto ◽  
Juan Carlos Otero ◽  
Francesco Muniz-Miranda ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Raman Scattering ◽  
Active Sites ◽  
Density Functional ◽  
Surface Enhanced Raman Scattering ◽  
Sers Spectrum ◽  
Functional Theory ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

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.

Chemical adsorption of salicylate on silver - A systematic approach to the interpretation of surface-enhanced vibrational spectra

2004 ◽  
Vol 82 (6) ◽  
pp. 987-997 ◽  
Author(s):  
P J.G Goulet ◽  
R F Aroca
Keyword(s):  
Salicylic Acid ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Density Functional ◽  
Ir And Raman Spectra ◽  
Chemical Adsorption ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Ir And Raman

In this work, surface-enhanced vibrational spectroscopy and normal vibrational spectroscopy as well as density functional theory (DFT) computational methods have been employed to investigate the nature of the chemical adsorption and orientation of the surface species generated from salicylic acid at silver surfaces. The structure of salicylic acid and its IR and Raman spectra are determined at the B3LYP/6-311+G(d,p) level of theory. These results are used in the assignment of the vibrational spectra. Surface-enhanced Raman scattering (SERS) spectra obtained from silver island films thinly coated with salicylic acid confirm chemical adsorption on the Ag nanostructures. To probe the nature of this surface complex, the optimized geometries and IR and Raman spectra of two model salicylate-silver complexes (Ag1 and Ag2) were calculated at the B3LYP/Lanl2DZ level of theory. It was found that good agreement exists between experimentally observed SERS spectra and the simulated SERS spectra of a complex with the salicylate monoanion bound to a Ag+ ion through its carboxylate group (Ag1). The carboxylate silver salt of salicylic acid (essentially the Ag1 complex) was also prepared, and its IR and Raman spectra were recorded for comparison with the surface-enhanced vibrational spectra. These results, along with the application of surface selection rules, suggest that salicylic acid is deprotonated at silver surfaces, interacting through its carboxylate group alone, and is preferentially in a tilted head-on orientation.Key words: chemisorption, salicylic acid, silver, density functional theory, surface-enhanced Raman scattering, reflection-absorption IR spectroscopy, surface-enhanced IR absorption.

scholarly journals Surface-enhanced Raman scattering of pyrazine on Au5Al5 bimetallic nanoclusters

RSC Advances ◽  
2017 ◽  
Vol 7 (20) ◽  
pp. 12170-12178 ◽  
Author(s):  
Quanjiang Li ◽  
Qianqian Ding ◽  
Weihua Lin ◽  
Jiangcai Wang ◽  
Maodu Chen ◽  
...  
Keyword(s):  
Density Functional ◽  
Dft Method ◽  
Time Dependent ◽  
Functional Theory ◽  
Bimetallic Nanoclusters ◽  
Surface Enhanced ◽  
Td Dft ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Dependent Density

In this study, we theoretically investigated the Raman and absorption spectra of pyrazine adsorbed on Au5Al5 bimetallic nanoclusters by a time-dependent density functional theory (TD-DFT) method.

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