Derivatization
Mostrando 13-24 de 230 artigos, teses e dissertações.
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13. Evaluation of Techniques for Determination of Hydroxyl Value in Materials for Different Industrial Applications
ABSTRACT When some materials need to be characterized, the hydroxyl number (IOH) determination is especially useful, mainly for those applied in the aerospace field. Usually, this characterization is performed by wet chemistry, using methodologies involving several steps, such as derivatization. This is a time-consuming and costly step. On the other hand, wh
J. Aerosp. Technol. Manag.. Publicado em: 04/04/2019
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14. Mimicking Ketonuria in the Ketogenesis Defect 3-Hydroxy-3-MethylglutarylCoenzyme A Lyase Deficiency: An Artefact in the Analysis of Urinary Organic Acids
Abstract 3-Hydroxy-3-methylglutaryl-coenzyme A lyase (HMGCL, HMGCL) deficiency is a rare inborn error of ketogenesis. Even if the ketogenic enzyme is fully disrupted, an elevated signal for the ketone body acetoacetic acid is a frequent observation in the analysis of urinary organic acids, at least if derivatization is performed by methylation. We provide an
J. inborn errors metab. screen.. Publicado em: 28/02/2019
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15. Fast Triacylglycerol Screening and Semi-Quantitative Analysis of Fatty Acids in Commercial Oils by DIMS with 18-Crown-6 Ether/Trifluoracetic Acid Dopants
Vegetable oil analyses, especially due to the complexity of the oil components, are commonly laborious, requiring several analytical techniques. In this work, electrospray ionization mass spectrometry with direct injection (DIMS), along with 18-crown-6 ether (crown ether) chelating agent and trifluoroacetic acid (TFA), was used to characterize and semi-quant
J. Braz. Chem. Soc.. Publicado em: 2019-02
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16. Non-isothermal decomposition kinetics of conductive polyaniline and its derivatives
Abstract The non-isothermal decomposition kinetics of conductive polyaniline (PANI) and its derivatives, poly(o-methoxyaniline) (POMA) and poly(o-ethoxyaniline) (POEA), was investigated by thermogravimetric analysis (TGA), under inert and oxidative atmospheres, using Flynn-Wall-Ozawa’s approach to assess the kinetic parameters of the decomposition process
Polímeros. Publicado em: 21/09/2018
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17. Analytical Method Development for Fatty Acid Direct Methylation in Fruits
Due to the amount of pigments, sugars and fibers found in fruits, the fatty acid quantification process leads to errors, such as its amount underestimation in the matrix. Therefore, the proposed method allows performing experiments in shorter time with reduced amount of sample and reagent. Design Expert software was used to find the validated time for alkali
J. Braz. Chem. Soc.. Publicado em: 2018-08
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18. Anti-Trypanosoma Activity and Synergistic Effects of Natural and Semi-Synthetic Triterpenes and Predominant Cell Death through Autophagy in Amastigote Forms
Chagas' disease is a parasitic disease with unsatisfactory treatment, mainly in chronic stage. This study aimed to evaluate the trypanocidal activity and action mechanisms of α/β-amyrin and its semi-synthetic derivatives, together with four isolated natural triterpenes, tested against trypomastigote and amastigote forms. The structure-activity relationship
J. Braz. Chem. Soc.. Publicado em: 2017-12
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19. Box–Behnken experimental design for extraction of artemisinin from Artemisia annua and validation of the assay method
ABSTRACT Obtaining artemisinin and its derivatives is very costly, which limits access to low-income people. Some hydroalcoholic extract of Artemisia annua L., Asteraceae, which has shown comparable antimalarial activity could be an alternative to the purified compound, especially if the cultivars have higher content of artemisinin. The objective of this stu
Rev. bras. farmacogn.. Publicado em: 2017-08
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20. Central Composite Design to Optimizate the Derivatization Procedure for Analysis of Biogenic Amines by HPLC-UV
A simple benzoylation procedure was optimized for the biogenic amines derivatization prior to high-performance liquid chromatography determination. The significant factors affecting biogenic amine benzoylation yield were optimized by central composite design (CCD). The obtained optimal conditions resulted in a chromatographic peaks area increase with fewer i
J. Braz. Chem. Soc.. Publicado em: 2017-04
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21. Free amino acid profile of Bubalus bubalis L. meat from the Campania region
ABSTRACT In this study, we determined the amount of carnosine and anserine in water buffalo meat without hanging treatment and the free amino acid profile by using amino acid analyser with post-column ninhydrin derivatization procedure. The main free amino acids present in samples were glutamic acid (>60 mg/100 g), followed by alanine, glycine, and arginine.
R. Bras. Zootec.. Publicado em: 2016-10
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22. Identification and Synthesis of the Male-Produced Sex Pheromone of the Soldier Beetle Chauliognathus fallax (Coleoptera: Cantharidae)
Chauliognathus fallax Germar 1824 (Coleoptera: Cantharidae) occurs in North and South America and Australia. Gas chromatographic (GC) analyses of volatiles released by adults showed the presence of a male specific compound. GC coupled with electroantennographic detection (GC-EAD) showed that this compound is exclusively bioactive on female antennae, suggesti
J. Braz. Chem. Soc.. Publicado em: 2016-08
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23. A New Fluorescence Method for Determination of Ammonium Nitrogen in Aquatic Environment Using Derivatization with Benzyl Chloride
We introduce a novel approach in simple and highly sensitive fluorometric determination of ammonium nitrogen. The proposed method is based on a fluorescence derivatization with benzyl chloride. The benzyl chloride was converted to a new fluorescent derivative by reaction with ammonium ion (NH4+) in the presence of sodium bicarbonate. The excitation and emiss
J. Braz. Chem. Soc.. Publicado em: 2016-05
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24. CRAQUEAMENTO TÉRMICO DA GLICERINA: UMA PROPOSTA DE EXPERIMENTO PARA QUÍMICA ORGÂNICA
In this work, an undergraduate organic chemistry experiment based on thermal cracking of glycerin is proposed. The reagent is obtained as a by-product from the practice of biodiesel synthesis, and allows reduction of waste produced in the lab. The main product obtained from thermal cracking was characterized by GC analysis as acrolein. This substance was
Quím. Nova. Publicado em: 2015-06