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Aplicação de técnicas espectrométricas, cromatográficas e quimiométricas na avaliação da autenticidade de plantas utilizadas como fitoterápicos
(Universidade Federal de São Carlos, 2006-08-01) Daolio, Cristina; Ferreira, Antonio Gilberto; https://lattes.cnpq.br/3676462220401452; https://lattes.cnpq.br/0173677456119225
The use of herbal medicines in the Brazilian market has increased in the last few decades. Therefore, the quality control for herbal products, as well as traditional medicines, is extremely important and for both: the manufactured products and the raw material. However, to guarantee the product s quality implies in an increase of the process costs in an industry. Currently, the quality of herbal extracts is predicted by analysis of selected marker compounds, which are often characteristic chemicals of a specific herb, but that many times do not present any relation with bioactivity. As a consequence, the marker-based approach is an incomplete and unsatisfactory method for quality control of herbal medicines In order to cope with this problem, current developments in improving sensitivity and analytical capacity of known techniques, had made possible the plant s complex extract evaluation. The present work describes an analytical methodology for the phytomedicines catuaba, espinheira-santa and guaco, based on the metabolic profile approach, where the Nuclear Magnetic Resonance techniques, as well as the High Performance Liquid Chromatography, are employed to obtain a fingerprinting of these herbal medicines. Nevertheless, due to the complex spectral data profile (1H spectra and chromatograms) evaluation it was necessary to employ chemometrics. These multivariate methods made possible to extract some relevant information and to prove the authenticity of the analyzed commercial samples. The commercial catuaba samples analysis by HR-MAS NMR/ chemometrics showed be more efficient, when compared with liquid NMR, indicating that the species sold as the phytomedicine catuaba is Trichillia catigua. Whereas, the results obtained for espinheira-santa showed an opposite situation pointing out that the efficiency of the HR-MAS is correlated with the physiological constitution of the plant material analyzed. Beside NMR results, HPLC analysis showed that the majority of the espinheira-santa commercial samples do not employ Maytenus ilicifolia species. The guaco results obtained by both, NMR and HPLC techniques were inconclusive needing the use of a complementary technique. Therefore, the present work also describes the use of the High Performance Liquid Chromatography coupling with Abstract Tandem Mass Spectrometry, by means of SRM experiments, to evaluate some commercial guaco samples. This technique provides the detection of the coumarin 1,2-benzopyrone in all the analyzed samples, due to the SRM high sensitivity, thus certifying its authenticity. The results obtained by Nuclear Magnetic Resonance, High Performance Liquid Chromatography and chemometrics, proved to be valuable tools for the evaluation of complex phytomedicines matrix. In specific cases, where high sensitivity in the analytical method is required, Mass Spectrometry can be used as an additional technique.
Medidas de condutividade na caracterização de complexos inorgânicos: um levantamento bibliográfico
(Universidade Federal de São Carlos, 2006-08-01) Velho, Rodrigo Garcia; Batista, Alzir Azevedo; https://lattes.cnpq.br/6469642481998660
In this work was done a review of the data published in inorganic chemistry journals (Inorganic Chemistry and Inorganica Chimica Acta in the years 1973-2005 and 1983-2005, respectively) on values of measurements of conductivity of coordination compounds in organic solvents and water. The main objective of the work was up to date the data collect by GEARY in his paper The use of conductivity measurements in organic solvents for the characterization of coordination compounds published in the journal in 1971 . The data of the conductivity of the complexes were listed o a table according to the solvent used for the measurements in the respective electrolyte and the final propose of the work was to establish a range of conductivity for each type of electrolyte.
Análise do comportamento da fluidodinâmica do leito de jorro com misturas de tamanho de partículas
(Universidade Federal de São Carlos, 2006-08-01) Bacelos, Marcelo Silveira; Freire, José Teixeira; https://lattes.cnpq.br/2270677706718167
This research study presents an investigation to quantify the stability of spouting regimes (by pressure fluctuations) and particle segregation level in conical spouted beds operated with a variety of particle combinations with uniform size or size distribution. In the presence of glycerol, a study on the effect of interparticle forces in the conical spouted bed fluid dynamics behavior with inert particle mixtures was also employed. Data show that, at a standard deviation from pressure signals of 50 Pa, in beds composed of inert particle of uniform size or size distribution stable spouting regime can be achieved. Moreover, the analysis of segregation indexes revealed that particle segregation becomes less pronounced as dpL/dpS is reduced from 2.85 to 1.98 and bed height is increased from 0.105 to 0.195 m. When glycerol is added into the bed, the results show that the dimensionless minimum spouting velocity (vmj/vmj0) does not change significantly with increase in glycerol concentration for the reference mixture. However, for all other mixtures of dpL/dpS > 1.98 employed, vmj/vmj0 increases with increase in the glycerol concentration into the bed, and this increase is more pronounced for flat and binary mixtures. The dimensionless of minimum spouting pressure drop (∆Pmj/∆Pmj0) decreases with increase in the glycerol concentration for all mixtures used. The application of a theoretical analysis, predicting the interparticle forces, shows that the change in minimum spouting condition as glycerol concentration increases can be explained by the magnitude of these forces.