Isabel C. P. Fortes

Efeito acaricida de óleos essenciais e concentrados emulsionáveis de Eucalyptus spp em Boophilus microplus

Realizou-se um estudo sobre a acao biocida de Eucalyptus citriodora, Eucalyptus globulus e Eucalyptus staigeriana no carrapato Boophilus microplus, buscando-se a producao de acaricidas menos agressivos ao meio ambiente. Os oleos essenciais das tres especies e os concentrados emulsionaveis de E. globulus e E. staigeriana foram testados em cinco concentracoes diferentes contra larvas e femeas ingurgitadas de B. microplus. Os oleos foram submetidos a analise por cromatografia gasosa acoplada a espectrometria de massas (CG/EM), a fim de se investigar sua composicao. O citronelal e o principal componente do oleo de E. citriodora, sendo responsavel por sua acao acaricida. O mesmo ocorre com o 1,8-cineol em E. globulus. Em E. staigeriana existem varias substâncias que agem sinergicamente contra B. microplus. O oleo essencial de E. citriodora matou 100% dos carrapatos a uma concentracao media de 17,5%, o de E. globulus a 15% e o de E. staigeriana a 12,5%. Os concentrados emulsionaveis de E. globulus mataram 100% dos carrapatos a uma concentracao media de 9,9% e o de E. staigeriana a uma concentracao de 3,9%. O desenvolvimento de produtos que possam ser testados a campo e comercializados a precos competitivos serao passos a serem seguidos. Os biocarrapaticidas tem um apelo comercial grande, permitindo controlar B. microplus de um modo menos agressivo ao meio ambiente.

Synergistic bactericidal activity of Eremanthus erythropappus oil or β-bisabolene with ampicillin against Staphylococcus aureus

The activity of Eremanthus erythropappus oil (EO) and some of its compounds and their potential synergistic interaction with ampicillin against different strains of Staphylococcus aureus were investigated. Determination of chemical composition of EO by gas chromatography-mass spectrometry (GC/MS) and bioguided chemical fractionation led to the identification of β-bisabolene as the main active compound. A synergistic bactericidal activity of EO or β-bisabolene with ampicillin against Staphylococcus aureus was observed in a time-kill assay. EO and β- bisabolene have the potential to restore the effectiveness of ampicillin against resistant S. aureus.

Determination of biodiesel adulteration with raw vegetable oil from ATR-FTIR data using chemometric tools

-1 . The explained variance was of 99% for the first three components. To quantify the raw soybean oil partial least squares (PLS) tool was applied. The best results were obtained for the spectral range of 1800-1000 cm -1 , with values of RMSEP (root mean square error of prediction) varying from 1.10 to 1.47% (m/m).

Avaliação da eficiência das técnicas ESI-MS e ATR/FTIR na determinação de adulteração de BX com querosene e óleo residual

Direct infusion electrospray ionization mass spectrometry in the negative ion mode, ESI(-)-MS and Fourier transform infrared spectroscopy (FTIR) were used together with partial least squares (PLS) as a tool to determine B3 adulteration (B3 - mixture of 3% v/v of biodiesel in diesel) with kerosene and residual oil.

Determination of sulfur in diesel using ATR/FTIR and multivariate calibration

The aim of this present work was to provide a more fast, simple and less expensive to analyze sulfur content in diesel samples than by the standard methods currently used. Thus, samples of diesel fuel with sulfur concentrations varying from 400 and 2500 mgkg-1 were analyzed by two methodologies: X-ray fluorescence, according to ASTM D4294 and by Fourier transform infrared spectrometry (FTIR). The spectral data obtained from FTIR were used to build multivariate calibration models by partial least squares (PLS). Four models were built in three different ways: 1) a model using the full spectra (665 to 4000 cm-1), 2) two models using some specific spectrum regions and 3) a model with variable selected by classic method of variable selection stepwise. The model obtained by variable selection stepwise and the model built with region spectra between 665 and 856 cm-1 and 1145 and 2717 cm-1 showed better results in the determination of sulfur content.

Utilização de uma interface do tipo "particle beam" para a obtenção de espectros de massas de compostos pouco voláteis em solução

Due to source contamination and wearing of instrument components problems caused by the direct insertion probe technique, a new way of introduction of low volatile compounds into mass spectrometer was tested. This new scheme comprises the introduction of the low volatile compounds solutions via a six port valve connected to a particle beam interface. Solutions of isatin were injected into this system and the best results were obtained with CH2Cl2, CH3OH and CH3CN. The solution inlet system has shown to be advantageous over the conventional way of direct insertion probe introduction.

Scientific analysis and historical aspects as tools in the legal investigation of paintings: A case study in Brazil

The faker makes use of several strategies to give credibility to his work, as for example by copying artists style or by using artificial aging techniques. The characterization of artistic materials, such as pigments, binding media and supports through chemical and/or physico-chemical analysis, coupled with art historical information is essential to establish the non-authenticity of works of art. This paper presents a contribution in a legal case regarding paintings attributed to important Brazilian and European artists such as Candido Portinari, Juan Gris, Camille Pissarro, and Umberto Boccioni, among others. In the investigation, modern synthetic painting materials were identified in all the ground layers of the suspected paintings. The use of diverse instrumental analytical techniques such as Fourier transform infrared spectroscopy, polarized light microscopy and pyrolysis-gas chromatography/mass spectrometry enabled this characterization. The results demonstrated the presence of titanium dioxide, calcium carbonate and kaolin as inorganic components of the paints, and polyvinyl acetate copolymerized with vinyl versatates or diisobutylphtalate as binding media in the ground layers of the paintings. The results obtained, along with art historical information and art technological studies, were very important in the judicial process, due to the possibility to use titanium dioxide and polyvinyl acetate copolymerized with vinyl versatates as chronological markers.