Graziella Trovati

Structural characterization of emeraldine-salt polyaniline/gold nanoparticles complexes

Gold nanoparticles (Au NPs) stabilized with polyamidoamine dendrimers (Au-PAMAM) or sodium citrate (Au-CITRATE) were synthesized and complexed with polyaniline emeraldine-salt form (ES-PANI). The complexes were characterized using structural and morphological techniques, including X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Zeta Potential analyses, and Fourier-Transformed Infrared spectroscopy (FTIR). When the Au-CITRATE NPs are added to the polymeric solution, the formation of a precipitate is clearly observed. The precipitate exhibited a different morphology from that found for ES-PANI and Au-CITRATE NPs, suggesting the formation of ES-PANI coating over the surface of Au-CITRATE NPs. On the other hand, when the Au-PAMAM NPs are incorporated into the ES-PANI solution, none interaction was observed, probably due to the repulsive electrostatic interactions, being the organization of the ES-PANI chains unaffected by the presence of the Au-PAMAM NPs.

Essential oil composition of Aloysia gratissima from Brazil.

Abstract The study of Aloysia gratissima essential oil from leaves was obtained by hydrodistillation using a Clevenger type apparatus. The essential oil composition was analyzed by GC and GC/MS. The major compounds were identified representing 94.7% of the oil. The most abundant compounds were isopinocamphone (cis-3-pinanone) (25.4%), limonene (15.1%), and guaiol (12.7%).

Nanocomposite based on polyaniline emeraldine-base and α-Al2O3: A structural characterization

Abstract A ceramic-matrix nanocomposite based on polyaniline emeraldine base and aluminum oxide (PANI-EB/α-Al2O3) was obtained by in-situ polymerization. X-ray diffraction pattern presented peaks related to both materials. The level of crystallinity was estimated at about 53%. The average crystallite sizes of PANI-EB and α-Al2O3 were found to be ∼40 Å and 570 Å, respectively. Scanning electron microscopy showed polymerization over ceramic particles. Fourier-transform infrared spectroscopy suggested physical deposition. The electrical conductivity of the PANI-EB/α-Al2O3 nanocomposite was decreased by a factor of 80 when compared with that of pure PANI-EB. Therefore, the polymeric reinforcement and the ceramic matrix maintained their original structural features, but the electrical conductivity in the nanocomposite was reduced.

Chemical Analysis of the Essential Oil Extracted from the Seeds of Licaria puchury-major

Abstract The essential oil from seeds of Licaria puchury-major was isolated by hydrodistillation. The chemical composition of the oil was analyzed by GC and GC/MS. Sixteen compounds were identified, representing 91.4% of the total oil. The major components were safrole (58.4%), dodecanoic acid (13.7%) and α-terpineol (8.4%). Oxygenated mono-terpenoids were the main group of compounds

Encapsulation of Piper aduncum and Piper hispidinervum essential oils in gelatin nanoparticles: a possible sustainable control tool of Aedes aegypti, Tetranychus urticae and Cerataphis lataniae : Encapsulation of P. aduncum and P. hispidinervum EOs in gelatin nanoparticles

BACKGROUND The encapsulated essential oils (EOs) of Piper aduncum L. and Piper hispidinervum C. DC. in gelatin nanoparticles were evaluated against Aedes aegypti Linn., Tetranychus urticae Koch and Cerataphis lataniae Boisd. RESULTS Encapsulation efficiency of the EOs was measured for absolute concentrations of 500 µg mL-1 (79.2 and 72.7%) and 1000 µg mL-1 (84.5 and 82.2%). The loaded nanoparticles were nearly spherical and well dispersed. The nanoparticles loaded with P. hispidinervum EO had an average size of 100 ± 2 nm, while the nanoparticles containing P. aduncum EO ranged from 175 ± 4 to 220 ± 4 nm. According to zeta potential analysis, the nanoparticles loaded with P. hispidinervum and P. aduncum EOs presented values around -43.5 ± 3 and -37.5 ± 2 mV respectively. The controlled release of EOs was described by the anomalous mechanism of Korsmeyer-Peppas. Both encapsulated EOs reached lethal dosages within 24 h of exposure and total mortality of the tested pests. CONCLUSION The present work successfully developed gelatin-based nanoparticles that served as carriers for the EOs of P. aduncum and P. hispidinervum to be applied as a sustainable control tool of A. aegypti, T. urticae and C. lataniae. The developed loaded nanoparticles presented high encapsulation efficiency and EO concentration release higher than lethal dosages. This indicates that it is feasible to use gelatin-based nanoparticles loaded with P. aduncum and P. hispidinervum EOs to control the tested pests.

TLC Separation and Identification of the Essential Oil Constituents from Aloysia gratissima

Abstract The present work had as objective the isolation of the five compounds by thin-layer Chromatography (TLC) from the essential oil of the Aloysia gratissima. For this, a number of systems of eluents were used for its separation, indicating that through the system acetone/hexane in proportions (v/v) 1:30 it was possible to isolate guaiol, elemol, pinocanphone (trans-3-pinanone), cis-pinocarvyl, and acorenone. The isolation of the compound acorenone from the other compounds was possible with the mixture of solvents hexane/dichloromethane in proportions (v/v) (1:1,3).