scholarly journals Microanalysis of Organic Pigments in Ancient Textiles by Surface-Enhanced Raman Scattering on Agar Gel Matrices

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Marilena Ricci ◽  
Cristiana Lofrumento ◽  
Emilio Castellucci ◽  
Maurizio Becucci
Keyword(s):  
Raman Scattering ◽  
Chemical Properties ◽  
Surface Enhanced Raman Scattering ◽  
Selective Extraction ◽  
Organic Pigments ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Long Time ◽  
Enhanced Raman Scattering ◽  
Selective Analysis

We review some new methods based on surface-enhanced Raman scattering (SERS) for the nondestructive/minimally invasive identification of organic colorants in objects whose value or function precludes sampling, such as historic and archeological textiles, paintings, and drawing. We discuss in detail the methodology we developed for the selective extraction and identification of anthraquinones and indigoids in the typical concentration used in textiles by means of an ecocompatible homogeneous nanostructured agar matrix. The extraction system was modulated according to the chemical properties of the target analyte by choosing appropriate reagents for the extraction and optimizing the extraction time. The system has been found to be extremely stable, easy to use and produce, easy to store, and at the same time able to be analyzed even after long time intervals, maintaining its enhancement properties unaltered, without the detriment of the extracted compound. Highly structured SERS band intensities have been obtained from the extracted dyes adopting laser light excitations at 514.5 and 785 nm of a micro-Raman setup. This analytical method has been found to be extremely safe for the analyzed substrates, thus being a promising procedure for the selective analysis and detection of molecules at low concentration in the field of artworks conservation.

scholarly journals Bromide-Assisted Anisotropic Growth of Gold Nanoparticles as Substrates for Surface-Enhanced Raman Scattering

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Melissa A. Kerr ◽  
Fei Yan
Keyword(s):  
Gold Nanoparticles ◽  
Raman Scattering ◽  
Chemical Properties ◽  
Surface Enhanced Raman Scattering ◽  
Synthetic Methods ◽  
Au Nps ◽  
Vis Spectroscopy ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

We report herein a one-step synthesis of gold nanoparticles (Au NPs) of various shapes such as triangles, hexagons, and semispheres, using 5-hydroxyindoleacetic acid (5-HIAA) as the reducing agent in the presence of potassium bromide (KBr). Anisotropic Au NPs have received ever-increasing attention in various areas of research due to their unique physical and chemical properties. Numerous synthetic methods involving either top-down or bottom-up approaches have been developed to synthesize Au NPs with deliberately varied shapes, sizes, and configurations; however, the production of templateless, seedless, and surfactant-free singular-shaped anisotropic Au NPs remains a significant challenge. The concentrations of hydrogen tetrachloroaurate (HAuCl4), 5-HIAA, and KBr, as well as the reaction temperature, were found to influence the resulting product morphology. A detailed characterization of the resulting Au NPs was performed using ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy. The as-prepared Au NPs exhibited excellent surface-enhanced Raman scattering (SERS) properties, which make them very attractive for the development of SERS-based chemical and biological sensors.

scholarly journals Clinical computed tomography and surface-enhanced Raman scattering characterisation of ancient pigments

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
Sveva Longo ◽  
Silvia Capuani ◽  
Francesca Granata ◽  
Fortunato Neri ◽  
Enza Fazio
Keyword(s):  
Computed Tomography ◽  
Raman Scattering ◽  
Surface Enhanced Raman Scattering ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Organic Pigments ◽  
Reconstruction Methods ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

<p class="Abstract">A systematic and complete chemical and physical characterisation of painted pigments on wood samples was carried out using multislice X-ray computed tomography (MSCT) and surface-enhanced Raman scattering (SERS) techniques. Inorganic and organic pigments present on the wooden tablets were differentiated by MSCT determinations of Hounsfield units, a semi-quantitative method for measuring X-ray attenuation that, in turn, offers an indirect estimation of a material’s density. However, the MSCT technique is not as reliable as traditional spectroscopic techniques for recognising and classifying organic pigments. Nevertheless, a strength of the MSCT approach was its ability to simultaneously provide a volumetric view of the wood and segment the layers of the specimen using suitable reconstruction methods such as is generally done for biomedical applications. Furthermore, the SERS technique made it possible to identify the type of material present in the pigments (for both inorganic or organic materials) with a high spatial resolution, even pigments in mixtures or those applied directly on the investigated wooden support. The combined MSCT and SERS data obtained through this systematic investigation constitutes the basis for the assembly of larger reference databases that will ultimately support the development of long-term conservation protocols.</p>

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