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187 results on '"Sanchez-Cortes S."'

23. Selective molecular recognition of polycyclic aromatic hydrocarbons (PAHs) on calix[4]arene-functionalized Ag nanoparticles by surface-enhanced Raman spectroscopy

Author

Leyton, P., Sanchez-Cortes, S., Garcia-Ramos, J.V., Domingo, C., Campos-Vallette, M., Saitz, C., and Clavijo, R.E.

Subjects
Molecular structure -- Research, Calixarenes -- Chemical properties, Raman spectroscopy -- Usage, Polycyclic aromatic hydrocarbons -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

Surface-enhanced Raman scattering (SERS) spectroscopy was used to detect trace concentrations of polycyclic hydrocarbons (PAHs). New SERS substrates were developed, which consisted Ag nanoparticles either in suspension or immobilized on glass, obtained by a new method and covered by adsorbed self-assembled calix[4]arene molecules.

Published
2004

42. Abiotic degradation of s‐triazine pesticides analyzed by surface‐enhanced Raman scattering.

Author

Rubira, R.J.G., Constantino, C.J.L., Otero, J.C., and Sanchez‐Cortes, S.

Subjects
RAMAN scattering, TRIAZINES, PESTICIDES, ORGANOPHOSPHORUS pesticides, ATRAZINE, HUMAN ecology
Abstract

In this work, we explore the use of surface‐enhanced Raman scattering (SERS) on silver (Ag) nanoparticles for the detection of triazine pesticide atrazine and prometryn as well as their degradation products. This tecnique was used to monitor the pesticide degradation both in the commercial samples as well as by the effects of heat and humidity. We have studied the adsorption affinity of these pesticides as well as their degradation products on the employed SERS substrates in order to check the optimal conditions in the detection of both the original pesticide and their degradation products. The presence of these products in triazine pesticides with high solubility in water is of great interest for the human health, but what's even more important is the fact that the pesticide degradation can be favored by very mild conditions of humidity, temperature, and pH, thus leading to high levels of structural modifications, which produce other final compounds with an even higher impact on both human health and environment. [ABSTRACT FROM AUTHOR]

Published
2020
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44. Carbon nanotube bundles as molecular assemblies for the detection of polycyclic aromatic hydrocarbons: Surface-enhanced resonance Raman Spectroscopy and theoretical studies

Author

Leyton, P., Gomez-Jeria, J.S., Sanchez-Cortes, S., Domingo, C., and Campos-Vallette, M.

Subjects
Raman spectroscopy -- Analysis, Nanotubes -- Chemical properties, Polycyclic aromatic hydrocarbons -- Structure, Polycyclic aromatic hydrocarbons -- Chemical properties, Polycyclic aromatic hydrocarbons -- Spectra, Chemicals, plastics and rubber industries
Abstract

Surface enhanced Raman spectroscopic experiments were used to demonstrate that metallic single-walled carbon nanotubes (CTs) could be used as chemical assemblies between the pyrene analyte and the silver colloidal surface. The polycyclic aromatic hydrocarbon (PAH) pyrene-nanotube interaction occurs through a [pi]-[pi] electronic stacking and energy transfer from the silver surface to the analyte system is observed.

Published
2006

45. Spectroscopic and biological properties of humic substances extracted from earthworm coprolites in a long-term experiment treated with manure and mineral fertilization

Author

Ertani, Andrea, Francioso, O., Pizzeghello, Diego, Tobar, E. L., Sanchez Cortes, S., Nardi, Serenella, Ertani A., Francioso O., Pizzeghello D., Lopez Tobar E., Sanchez-Cortes S., and Nardi S.

Subjects
AUXIN AND GIBBERELLIC-LIKE ACTIVITY, SERS, gel permeation chromatography, IR, giberellic-like activity, auxin-like activity, earthwarms coprolites, EARTHWORM COPROLITES
Abstract

Humic substances (HS) are the most important natural soil conditioners because they play an important role in guaranteeing long-term fertility. In this study the structure and biological properties of HS of earthworm faeces were investigated in order to better understand how fertilization practices can influence their chemical and biological properties. The study was conducted in the Experimental Farm of Padua University, at Legnaro (NE Italy 45° 21' N; 11° 58' E; 6 m a.s.l.) as part of the longest running rotation experiment in Italy. The soil is a fluvi-calcaric cambisol (CMcf), silty or sandy loam, with a sub-basic pH. The trial considers 4 treatments with maize as the main crop. These allow the comparison between fertilization with only organic (farmyard manure, 60 t ha-1 y-1, 20% d.m.), only mineral (high mineral input, 300 kg N ha y-1, 66 kg P ha y-1, 348 kg K ha y-1) or mixed inputs (farmyard manure, 30 t ha-1 y-1, 20% d.m. plus mineral input, 150 kg N ha y-1, 33 kg P ha y-1, 174 kg K ha y-1) and no fertilization. The experimental layout is a randomized block with three replicates, on plots of 7.8 × 6 m. The coprolites taken from each plot were treated with alkaline solution to extract the HS. Gel permeation chromatography, infrared spectroscopy and surface-enhanced Raman scattering (SERS) were applied to study the structure of HS. The biological activity of HS was also investigated by assaying the auxin and gibberellic-like activity. The results obtained have shown that a relationship exists between different fertilization practices and chemical and biological properties of HS produced by earthworms.

Published
2013

46. Study of the interaction of pollutant nitro polycyclic aromatic hydrocarbons with different metallic surfaces by surface-enhanced vibrational spectroscopy (SERS and SEIR)

Author

Carrasco F., E.A., Garcia-Ramos, J.V., Campos-Vallette, M., Inostroza, N., Leyton, P., Domingo, C., F., G. Diaz, Sanchez-Cortes, S., Clavijo, R.E., and Koch, R.

Subjects
Raman effect -- Research, Chemicals, plastics and rubber industries
Abstract

Surface-enhanced Raman scattering (SERS) and surface-enhanced infrared spectroscopy (SEIR) is applied to study the interaction of nitro polycyclic aromatic hydrocarbons (NPAHs) with metal surfaces. SERS and SEIR spectra suggest that the NPAHs 1-nitropyrene (1NP) and 2-nitrofluorene (2NF) at concentrations of [less than] 10(super -6) M (~200 ppb) interact with metal surfaces through the nitro group, adopting a perpendicular orientation onto the surface.

Published
2003

47. A Raman, SERS and UV-circular dichroism spectroscopic study of N-acetyl-L-cysteine in aqueous solutions.

Author

Picot, R. A. Cobos, Puiatti, M., Ben Altabef, A., Rubira, R. J. G., Sanchez-Cortes, S., Diaz, S. B., and Tuttolomondo, M. E.

Subjects
AQUEOUS solutions, SERS spectroscopy, MOLECULAR structure, RAMAN effect, NATURAL orbitals, IONIZATION constants, MOLECULAR polarizability
Abstract

The aim of this work is to evaluate the vibrational and structural properties of N-acetyl- L -cysteine (NAC), and its molecular structure and electronic properties in relation to the action of thiol and amine groups at different pH. Raman and Surface Enhanced Raman Spectroscopy (SERS) spectra were measured in aqueous solution. The influence of an aqueous environment on the NAC spectra was simulated by means of an implicit (polarizable continuum model) method. SERS spectra indicate that the S atom is interacting with the surface through the sulfur atom. One of the consequences of the interaction with the surface is the deprotonation of the SH group, as revealed by the disappearance of the ν(S–H) band. The calculations performed for the Ag–NAC complex confirm the experimental data obtained by SERS, where the S–Ag interaction is the most important. These results are very interesting when one can formulate the drug feasibility of NAC using silver nanoparticles as a carrier. Raman spectra were measured to compare the behavior of different functional groups in the molecule, both in the solid phase and in aqueous solution at different pH. Apparent ionization constants (pK′ values) for the S–H group at high ionic strengths were calculated from the intensity of the 2580 cm−1 frequency as a function of pH. UV and circular dichroism spectra were also measured in aqueous solution at different pH. Finally, the study was completed with natural bond orbital (NBO) analysis to determine the presence of hyper-conjugative interactions. It is important to observe the behavior of the C2–N bond with the delocalization effect; as the pH increases the hyperconjugative interaction of this bond decreases in the same way as in the case of νCN. The way in which the LP πO1 → σ*C2–N interaction and νCN decrease is an inverse reflection of the fractional ionization αSH. [ABSTRACT FROM AUTHOR]

Published
2019
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