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Mostrando 13-24 de 131 artigos, teses e dissertações.
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13. Measurement of Tannic Substances in Forest Species
ABSTRACT This study aimed to quantify the tannic content of the barks and fruit of angico-vermelho, jurema-preta and acacia-negra using skin powder as detanizador agent. Materials from these species were ground and classified, with 12.5g of air dried particles subjected to extraction using a steam jacket type extractor to obtain 1000 ml of solution, using a
Floresta Ambient.. Publicado em: 14/06/2018
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14. Synthesis of Chelating Agent Free-Solid Phase Extractor (CAF-SPE) Based on New SiO2/Al2O3/SnO2 Ternary Oxide and Application for Online Preconcentration of Pb2+ Coupled with FAAS
A new online solid phase preconcentration method using the new SiO2/Al2O3/SnO2 ternary oxide (designated as SiAlSn) as chelating agent free-solid phase extractor (CAF-SPE) coupled to flame atomic absorption spectrometry (FAAS) for Pb2+ determination at trace levels in different kind of samples is proposed. The solid adsorbent has been characterized by Fourie
J. Braz. Chem. Soc.. Publicado em: 2018-06
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15. Use of Mixture Design with Minimal Restrictions to Optimize an Extraction Procedure Employing Diluted Acids Assisted by Ultrasound and Microwave for Nutrient Element Determination in Vegetal Samples
In this work, it was developed an alternative analytical strategy for the preparation of vegetal samples extracted with diluted acids and assisted by ultrasound and microwave radiation for the determination of nutrients elements by fast sequential flame atomic absorption spectrometer. The conditions optimized using univariate and multivariate methodologies f
J. Braz. Chem. Soc.. Publicado em: 2018-06
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16. OTIMIZAÇÃO DA EXTRAÇÃO SÓLIDO-LÍQUIDO COM PARTIÇÃO EM BAIXA TEMPERATURA PARA DETERMINAÇÃO DE CARBOFURANO EM Cucurbita pepo L (“ABOBRINHA”) POR CROMATOGRAFIA LÍQUIDA DE ALTA EFICIÊNCIA
According to results of the Program of Analysis of Pesticide Residues in Foods of the National Agency of Sanitary in Brazil (2013 to 2015) the zucchini, Cucurbita pepo L is one of the non-hardy vegetables, that presented higher contamination index by pesticides residues. One of these agrochemicals is carbofuran, which although not authorized for this crop, i
Quím. Nova. Publicado em: 2018-02
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17. Irrigation and Light Access Effects on Coffea arabica L. Leaves by FTIR-Chemometric Analysis
Coffee bean chemical compositions has been extensively studied. However, there is a small amount of research on other parts of the coffee plant, including leaves. Fourier transform infrared (FTIR) spectral profiles of Coffea arabica L. cv. IAPAR 59 leaf extracts from a simplex-centroid design were studied by principal component analysis (PCA) to evaluate the
J. Braz. Chem. Soc.. Publicado em: 2018-01
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18. DEVELOPMENT AND OPTIMIZATION OF A MICROWAVE-ASSISTED EXTRACTION OF PLUMIERIDE FROM Allamanda cathartica L. FLOWERS
A simple and efficient microwave-assisted extraction process has been developed in order to extract plumieride from Allamanda cathartica flowers. The extracts have been obtained through microwave-assisted extraction (MAE) process with ethanol and ethyl acetate at different time, power and temperatures. Static maceration at room temperature with ethanol and e
Quím. Nova. Publicado em: 2018-01
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19. Some triterpenic compounds in extracts of Cecropia and Bauhinia species for different sampling years
ABSTRACT The aim of this paper is to provide an overview on the chemical composition of triterpenes in widespread used folk medicine species, through the development and validation of eleven compounds using HPLC-UV detection. The compounds were separated using isocratic elution, on a reverse phase column (Kinetex C18, 250 mm × 4.6 mm, 5 µm) with mobile pha
Rev. bras. farmacogn.. Publicado em: 2018-01
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20. ALÉM DA CAIPIRINHA: CACHAÇA COMO SOLVENTE PARA SÍNTESE ORGÂNICA E EXTRAÇÃO DE PIGMENTO
Cachaça (brazilian sugarcane spirit) was applied for the first time as an alternative solvent in undergraduate experiments of organics synthesis, and natural dye extraction. The classical Claisen-Schmidt condensation of benzaldehyde with acetophenone and with acetone were employed to demonstrate the cachaça viability as solvent. Cachaça was also the recry
Quím. Nova. Publicado em: 2017-10
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21. Characterization of microencapsulated cardamom (Elettaria cardamomum) oil extracted using supercritical fluids on a semi-industrial scale
Abstract The objective of this study was to find the optimal conditions to obtain cardamom oil extracted by SCF on a semi-industrial scale, with yields equal or superior to those obtained using the conventional methods, but with sensory quality and a technique competitive for international markets. In addition microcapsules were produced allowing for an incr
Braz. J. Food Technol.. Publicado em: 20/07/2017
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22. Direct Incorporation of Ginger and Oregano Antioxidants in Canola Oil
Antioxidants are used to increase the shelf life of food and oils. The most common extraction method of antioxidants from natural sources is the use of organic solvents, like methanol and ethanol. Evaporation of all the organic solvent is necessary to prevent health diseases. In this study, we present a new "organic solvent-free" method to extract antioxidan
J. Braz. Chem. Soc.. Publicado em: 2017-06
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23. Pharmacognostic evaluation, and development and validation of a HPLC-DAD technique for gallocatechin and epigallocatechin in rhizomes from Limonium brasiliense
ABSTRACT Limonium brasiliense (Boiss.) Kuntze, Plumbaginaceae, is a plant from the southern coast of Brazilian that is used for the treatment of premenstrual syndrome, menstrual disorders and genito-urinary infections. The aim of the present study was to determine the quality control parameters for rhizomes collected during different periods by pharmacopoeia
Rev. bras. farmacogn.. Publicado em: 2017-04
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24. Solid Phase Extraction to On-Line Preconcentrate Trace Cadmium Using Chemically Modified Nano-Carbon Black with 3-Mercaptopropyltrimethoxysilane
Carbon black (CB) grafted with 3-mercaptopropyltrimethoxysilane (3-MPTMS) was used as solid phase extractor for Cd2+ in a flow injection system coupled to flame atomic absorption spectrometry (FAAS). The influence of pH, buffer concentration, preconcentration flow rate and eluent concentration on preconcentration of Cd2+ were investigated by means of chemome
J. Braz. Chem. Soc.. Publicado em: 2016-10