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Mostrando 13-24 de 158 artigos, teses e dissertações.
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13. DEVELOPMENT OF AN AUTOMATED METHOD TO PERFORM A QUANTITATIVE STUDY OF PARTICLE SIZE DISTRIBUTION AND THE EFFECT OF A CONDUCTIVE LAYER IN SCANNING ELECTRON MICROSCOPY
The determination of particle size distribution is an important parameter for controlling industrial processes, particularly in the field of pharmaceuticals. It is also an important parameter for characterizing nanoparticles. The best technique for determining particle size distribution is scanning electron microscopy. The process of counting particles is ty
Quím. Nova. Publicado em: 27/05/2019
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14. Automatized Separation of Fractions from Petroleum Based on Spectrophotometric Signal Derivative Using Open-Source Hardware for the Determination of Ni and V Linked to Porphyrins
An automated method based on open-source hardware was created for the separation of porphyrins fractions from crude oil, an essential step for the quantification of V and Ni as metalloporphyrins. Preparative liquid chromatography was implemented with a reverse phase gradient from MeOH to toluene. The system allows three solvents and fractions changes by usin
J. Braz. Chem. Soc.. Publicado em: 23/05/2019
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15. Fit-for-Purpose ICP-MS Procedure Supporting Brazilian Regulations on Inorganic Constituents in Fresh and Saline Waters
This work aimed the development of an analytical procedure using inductively coupled plasma mass spectrometry (ICP-MS) in four modes of operation for simple and fast determination of Al, Ag, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Na, Ni, Pb, Sb, Se, Tl, Hg, V, U, and Zn in fresh and sea water samples attending simultaneously four Brazilian regula
J. Braz. Chem. Soc.. Publicado em: 2018-07
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16. 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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17. Determination of Chlorine in Crude Oil Emulsified via the MgCl Molecule by HR-CS MAS
A method for chlorine determination in crude oil samples, through the formation of MgCl molecule, by high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) was developed and is described in this paper. The use of this molecule for chlorine determination in crude oil has not been reported up to now. Measures were ca
J. Braz. Chem. Soc.. Publicado em: 2018-03
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18. Rhodolirium andicola: a new renewable source of alkaloids with acetylcholinesterase inhibitory activity, a study from nature to molecular docking
ABSTRACT Acetylcholinesterase is an important target for control of neurodegenerative diseases causing cholinergic signaling deficit. Traditionally, galanthamine has been used as an Amaryllidaceae-derived acetylcholinesterase inhibitor, although new Amaryllidaceae plants could serve as source for better acetylcholinesterase inhibitors. Therefore, the objecti
Rev. bras. farmacogn.. Publicado em: 2018-01
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19. Identificação de compostos orgânicos voláteis de vinhos brasileiros de diferentes castas por microextração em fase sólida
Resumo A indústria vinícola brasileira apresentou crescimento significativo nos últimos anos e a inserção de conceitos ‒ como, por exemplo, indicações geográficas como sinais de qualidade ‒ colocou o Brasil em sintonia com as tendências da produção mundial. Este trabalho objetivou aplicar a técnica de microextração em fase sólida em combi
Braz. J. Food Technol.. Publicado em: 2018
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20. Evaluation of Distribution and Bioaccumulation of Arsenic by ICP-MS in Tilapia (Oreochromis niloticus) Cultivated in Different Environments
The concentration of arsenic in tissues of tilapia was evaluated and an estimation of the risks associated with the consumption of this fish was done, taking into account the guidelines established by FAO/WHO. The inductively coupled plasma mass spectrometry (ICP-MS) technique in kinetic energy discrimination (KED) mode was employed and certified reference m
J. Braz. Chem. Soc.. Publicado em: 2017-12
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21. Ion Exchange Chromatography and Mass Bias Correction for Accurate and Precise Zn Isotope Ratio Measurements in Environmental Reference Materials by MC-ICP-MS
Precise and accurate d66/64Zn data for environmental reference materials (RMs) including rocks, sediments, soils and plants are presented in order to improve the metrological traceability and analytical control of Zn isotope ratio determinations in future environmental studies. Previously developed ion exchange chromatography protocols were adjusted to enabl
J. Braz. Chem. Soc.. Publicado em: 2017-02
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22. Speciation of Chromium in Water Samples after Dispersive Liquid-Liquid Microextraction, and Detection by Means of High-Resolution Continuum Source Atomic Absorption Spectrometry
A newly analytical method has been developed to determine total chromium and speciation of this element in water samples through dispersive liquid-liquid microextraction combined with a high-resolution continuum source flame atomic absorption spectrometry. The most significant variables affecting complexation and extraction were optimized by using response s
J. Braz. Chem. Soc.. Publicado em: 2017-02
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23. Evaluation of Inductively Coupled Plasma Tandem Mass Spectrometry for Determination of As in Agricultural Inputs with High REE Contents
In the present work, an inductively coupled plasma-tandem mass spectrometer (ICP-MS/MS) operating in single quadrupole and mass shift modes were evaluated for As determination in mineral fertilizers and agricultural gypsum with high contents of rare earth elements. For MS/MS mode, oxygen was the gas introduced into the octopole reaction system (ORS3). Sample
J. Braz. Chem. Soc.. Publicado em: 2016-11
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24. Strategy of Sample Preparation for Arsenic Determination in Mineral Fertilizers
A method for determination of arsenic in mineral fertilizers by continuous flow hydride generation atomic absorption spectrometry (CF-HG-AAS) was developed by using diluted acid and digester block with perfluoroalkoxy (PFA) tubes to sample preparation. An additional sample preparation procedure using microwave-assisted digestion was evaluated and compared wi
J. Braz. Chem. Soc.. Publicado em: 2016-06