Chemical Analyses
Mostrando 1-12 de 1229 artigos, teses e dissertações.
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1. Evaluation of sediment contamination by urban sewage in a stretch of Capibaribe River, Pernambuco, Brazil
Anthropic activities are responsible for the increase in environmental contamination, especially in aquatic systems, demanding studies to assess and monitor contamination levels in different water bodies. We have done a chemical characterization of eleven sediments in order to evaluate the level of contamination by domestic sewage from the Capibaribe River,
Química Nova. Publicado em: 2022
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2. Synthesis and Molecular Modeling Study of Two Bromo-Dimethoxybenzaldehydes
This work describes the synthesis, molecular structure, and packaging of the compounds 6-bromo-2,3-dimethoxybenzaldehyde (6-BRB) and 5-bromo-2,3-dimethoxybenzaldehyde (5 BRB). Characterization in the solid-state was carried out by X-ray diffraction, and the analysis of the interactions was described by the Hirshfeld surface, which helps in understanding the
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. Spectroscopic techniques combined with chemometrics to study organic matter in tropical soils with different degrees of pedogenetic evolution
Understanding of the organomineral interactions in soil can elucidate the humic substances (HS) formation and the humification process. This study aimed to structurally characterize the humic acids (HA) formed in tropical soils with different pedogenesis degrees. The HA fraction was extracted from soil samples in the superficial horizons of an Inceptisol and
Química Nova. Publicado em: 2022
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4. Evaluation of residues of β-lactam, sulfonamide, tetracycline, quinolone, fluoroquinolone e pyrimidine in raw milk
Abstract Food quality and safety have been a concern of the world population, especially in relation to the chemical and microbiological hazards present in food. The presence of antimicrobial residues at levels above the maximum residue limit makes milk unsuitable for human consumption. In this context, the objective of this study was to analyze 184 raw milk
Food Sci. Technol. Publicado em: 2021-09
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5. Methanolic Extract of Rhinella marina Poison: Chemical Composition, Antioxidant and Immunomodulatory Activities
This study investigated the chemical composition, immunomodulatory and antioxidant activities, and histopathological analysis of mice tissues treated with methanolic extract from R. marina poison. Marinobufagin, telecinobufagin and bufalin were identified in the chemical profile. The biochemical results demonstrated an effect between doses in the period of 7
J. Braz. Chem. Soc.. Publicado em: 2021-08
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6. Stability Analyses by HPLC-MS of Guanitoxin Isolated from Sphaerospermopsis torques-reginae
Guanitoxin (GNT) is a natural organophosphate produced by some species of freshwater cyanobacteria, which inhibits the active site of acetylcholinesterase, preventing the hydrolysis of cholinesterases and consequently causing serious disturbances in the neuromuscular system. Despite having a chemical structure like synthetic organophosphates, there is still
J. Braz. Chem. Soc.. Publicado em: 2021-08
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7. Through-Bond and Through-Space Interactions in [2,2]Cyclophanes
The interpretation of the distortions of the electron distribution in [2,2]cyclophanes (22-CPs) is controversial. Some studies indicate that there is an accumulation of electron density (ρ) outside the cavity of 22-CPs. The nature of through-space (ts) interaction is still under debate. The relative importance of ts and through-bond (tb) is an open question
J. Braz. Chem. Soc.. Publicado em: 2021-07
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8. Essential Oils Obtained from Aerial Eugenia punicifolia Parts: Chemical Composition and Antiproliferative Potential Evidenced through Cell Cycle Arrest
Essential oils (EOs) of the leaves of three Eugenia punicifolia specimens from two different Reservation Parks, namely Parque Nacional das Nascentes do Rio Parnaíba (EpNRP-I and EpNRP-II) and Parque Nacional da Chapada das Mesas (EpCM), in the state of Maranhão, Brazil, were extracted by hydrodistillation and investigated by gas chromatography coupled to m
J. Braz. Chem. Soc.. Publicado em: 2021-07
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9. Determination of physical and chemical properties of kombucha teas prepared with different herbal teas
Abstract In this research, kombucha tea was prepared using 5 different tea extracts and physicochemical and sensory analyses were made. The tea extracts used are black tea, green tea, sage, linden and mint, respectively. The prepared tea samples were subjected to fermentation for 14 days. In tea samples, pH, electrical conductivity, water-soluble solid and p
Food Sci. Technol. Publicado em: 2021-06
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10. Chemical and antioxidant characterization, sensory and shelf-life analysis of cereal bars with almonds from pequi (Caryocar brasiliense Camb.)
Abstract The study aimed to know how almonds from Pequi (Caryocar brasiliense Camb.), a byproduct of this fruit from Brazilian Cerrado, can be used to improve value to cereal bars. To respond to this question, the study characterized pequi almonds and cereal bars with pequi, and evaluate sensory acceptance. The preparation of cereal bars enriched with pequi
Food Sci. Technol. Publicado em: 2021-06
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11. Hymenaea parvifolia Huber: dormancy breaking, morphology of fruit, seed and seedling
ABSTRACT The successful use of native species in conservation actions depends on basic knowledge of their biology, beginning with the identification of regenerating individuals in the field, up to the behavior and development of the species from the early stages of germination. Moreover, seed propagation and germination may be limited by the occurrence of do
Rev. Ceres. Publicado em: 2021-04
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12. Evaluation of Lignins of Trunk and Roots from Citrus sinensis L. Osbeck: A Large Available Brazilian Biomass
Citrus biomass is a source of biobased products and presents extensive chemical diversity. Among the structural macromolecules, lignins have been used in resins, bioplastics, and nanoencapsulation. Brazil has a large source of lignins, which are orange trees removed from groves that need to be renewed. However, the knowledge about these lignins is limited an
J. Braz. Chem. Soc.. Publicado em: 2021-01