Identification of coexisting indigo species in an ancient green thread using direct plasmon-enhanced Raman spectroscopy
Autor
Celis, Freddy
Tirapegui, Cristian
García, Macarena
Aracena, Andrés
Aliaga, Álvaro. E.
Campos-Vallette, Marcelo
Resumen
A green ancient thread sample from a Chilean mummy turban was analyzed by plasmon-enhanced Raman scattering spectroscopy using a direct drop-colloidal method. The enhanced-Raman signals in the sample are associated with biomolecules from the thread and two coexisting dyes, indigo and leuco-indigo. The presence of indigo (blue colour) was identified from its most characteristic vibrational bands. Leuco-indigo (yellow colour) was identified for the first time in an ancient textile; its SERS signals are coincident with the SERS bands of a synthesized leuco-indigo. The interconversion leuco-indigo to indigo was followed by UV-visible spectroscopy. Based on theoretical calculations it is proposed that the interconversion involves a π electron delocalization mainly around the NC-CN bridge. The mixture of both dyes (indigo and leuco-indigo) is the responsible for the green colour observed.
Colecciones
Ítems relacionados
Mostrando ítems relacionados por Título, autor o materia.
-
Article
A simple method to estimate the mean number of lipophilic molecules on nanoparticle surfaces by fluorescence measurements (2021)
Adura, Carolina; Aliaga, Carolina; Silva, Francisco; Vera, Cristian; Pino, Eduardo; Celis, Freddy; Aracena, Andrés; Tirapegui, Cristian (NLM (Medline), 2021-05-14)Measurements of fluorescence intensity of the hydrophobic pyridinium salt (DTPSH) remaining in the organic phase after partition experiments in the DCM/H2O system allowed an approximate method to be developed to estimate ... -
Article
N-acetylcysteine reduces skeletal muscles oxidative stress and improves grip strength in dysferlin-deficient BLA/J mice (2020)
García-Campos P.; Báez-Matus X.; Jara-Gutiérrez C.; Paz-Araos M.; Astorga C.; Cea L.A.; Rodríguez V.; Bevilacqua J.A.; Caviedes P.; Cárdenas A.M. (MDPI AG, 2020) -
Article
Maldi-tof ms and 16s rna identification of culturable gastric microbiota: Variability associated with the presence of helicobacter pylori (2020)
Troncoso, Claudia; Pavez, Mónica; Cerda, Álvaro; Oporto, Marcelo; Villarroel, Daniel; Hofmann, Edmundo; Ríos, Eddy; Sierralta, Armando; Copelli, Luis; Barrientos, Leticia (MDPI AG, 2020-11-10)Helicobacter pylori is the main bacteria associated with gastroduodenal diseases. Recent studies have reported that gastric microbiota might be modified by the H. pylori colonization, favoring gastric lesions′ development. ...