Uv Spectrophotometry
Mostrando 13-24 de 135 artigos, teses e dissertações.
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13. Degradation of Poly(Ethylene Oxide) Films Using Crystal Violet
The present study aimed to investigate the degradation of poly(ethylene oxide) (PEO) in the presence of cationic dye crystal violet irradiated under visible light. The preparation of the samples was done in the form of films obtained by casting. Degradation tests were carried out by 120 hours at room temperature. The degradation kinetics of the dye and polym
Mat. Res.. Publicado em: 01/02/2018
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14. DETERMINAÇÃO DE ENXOFRE EM SHAMPOO POR ESPECTROFOTOMETRIA UV-VIS: AVALIAÇÃO DE MÉTODOS DE PREPARO DE AMOSTRAS
Dry ashing, dissolution in aqueous medium or wet digestion methods were evaluated for sample preparation of shampoo for the subsequent indirect determination of sulfur by UV-Vis spectrophotometry. Among the sample preparation methods evaluated, microwave-assisted wet digestion using 7 mol L-1 HNO3 was the most suitable method for this purpose. Accuracy of th
Quím. Nova. Publicado em: 2017-08
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15. Biosynthesized silver nanoparticles: are they effective antimicrobials?
BACKGROUND Silver nanoparticles (AgNPs) are increasingly being used in medical applications. Therefore, cost effective and green methods for generating AgNPs are required. OBJECTIVES This study aimed towards the biosynthesis, characterisation, and determination of antimicrobial activity of AgNPs produced using Pseudomonas aeruginosa ATCC 27853. METHODS
Mem. Inst. Oswaldo Cruz. Publicado em: 2017-08
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16. USO DA ESPECTROFOTOMETRIA UV-VIS PARA DIFERENCIAR AS COLORAÇÕES DO BIODIESEL DE PALMA E DO CORANTE MARCADOR DE ÓLEO DIESEL
Currently, there are two mixtures of biodiesel/diesel fuel sold in Brazil: BX/S500 and BX /S10 (X = volume/volume biodiesel percentage; S500 and S10 = sulfur content in diesel fuels - 500 ppm and 10 ppm, respectively). In order to differentiate these mixtures, red dye is added to diesel oil as required by the National Agency for Petroleum, Natural Gas and Bi
Quím. Nova. Publicado em: 2017-08
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17. Development of a Dissolution Test for Fenbendazole-Praziquantel Capsules Using UV-PLS Method
A dissolution test for capsules containing 50 mg of praziquantel and 500 mg of fenbendazole was developed and validated. The optimal conditions were an USP apparatus 2 with paddles rotating at 75 rpm, 900 mL dissolution medium (a mixture of 300 mL of ethanol and 600 mL 0.5 mol L-1 HCl), at 37.0 ± 0.5 °C. Both analytes achieved with sink conditions. A publi
J. Braz. Chem. Soc.. Publicado em: 2017-06
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18. Laccase-Assisted Rapid Synthesis of Colloidal Gold Nanoparticles for the Catalytic Reduction of 4-Nitrophenol
A green method for the rapid preparation of uniform-sized colloidal gold nanoparticles under ambient conditions was presented and validated using laccase as a reduction agent in alkaline medium. UV-Vis spectrophotometry, field-emission high-resolution transmission electron microscopy, X-ray diffraction, selected area electron diffraction, energy dispersive X
J. Braz. Chem. Soc.. Publicado em: 2017-06
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19. Synthesis, Characterization and Antimicrobial Activities of Copper, Nickel, Cobalt, Chromium Complexes Derived from (Z)-4-Fluoro-N-(2,7-dimethylhept-6-enylidene) benzenamine
Melonal is a relatively unexplored ingredient in the field of chemistry with excellent sensory properties. The synthesis and characterization of novel transition 3d metal complexes of copper(II), nickel(II), cobalt(II) and chromium(III) involving the Schiff base of melonal were explored to examine their biological activity. Characterization of the complexes
J. Braz. Chem. Soc.. Publicado em: 2017-05
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20. Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al2O3 Catalyst
A series of highly dispersed Pd/Al2O3 catalysts were prepared via the polyol method. The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), UV-Vis spectrophotometry, temperature programmed reduction (TPR) and transmission electron microscopy (TEM). The influence of Pd particle size on the hydrogenation of 2-amyl anthraquinone (AAQ)
J. Braz. Chem. Soc.. Publicado em: 2016-06
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21. Microscopic and UV/Vis spectrophotometric characterization of Cissampelos pareira of Brazil and Africa
ABSTRACT Cissampelos pareira L., belonging to Menispermaceae family, has worldwide distribution, occurring in tropical and subtropical regions of the Americas, Africa and Asia. It is the most popular species of Cissampelos, known for its medicinal uses of leaves and roots. The study aims to find distinctive leaf anatomical characters, and also demonstrate th
Rev. bras. farmacogn.. Publicado em: 2016-04
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22. Exploring the Versatility of an Atomic Absorption Spectrometer: Application to Direct Molecular Determination of Caffeine and Propranolol
A simple strategy using an atomic absorption spectrometer (AAS) for the direct determination of molecular compounds is proposed. The determination of caffeine and propranolol employing atomic absorption instrumentation was conducted, monitoring the emission lines of Fe (271.9 nm) and Mg (285.2 nm), respectively, using a quartz cuvette (1.0 cm) positioned in
J. Braz. Chem. Soc.. Publicado em: 2016-04
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23. PROPOSTA EXPERIMENTAL DIDÁTICA PARA O ENSINO DE ANÁLISE DE COMPONENTES PRINCIPAIS
Principal component analysis (PCA) is a chemometric method that allows for the extraction of chemical information that would otherwise be impossible to determine. Teaching chemometrics to undergraduates can contribute to the overall professional development and training of new teachers, whose profiles have been gaining attention due to the current demand for
Quím. Nova. Publicado em: 2016-02
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24. 2-(4-IODO-2,5-DIMETOXIFENIL)-N-[(2-METOXIFENIL)METIL]ETAMINA OU 25I-NBOME: CARACTERIZAÇÃO QUÍMICA DE UMA DESIGNER DRUG
Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5-dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotome
Quím. Nova. Publicado em: 2016-02