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Mostrando 1-12 de 544 artigos, teses e dissertações.
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1. Lipid Profile of Human Milk in Different Lactation Stages Submitted to Pasteurization, Lyophilization and Spray-Drying Processes
The objective of this study was to evaluate the effect of pasteurization, lyophilization and spray-drying on the lipid profile of donated human milk (DHM) at different lactation stages. Nine frozen samples of colostrum, transitional and raw mature human milk (HM) were collected from the Human Milk Bank (HMB) of the Hospital Universitário de Maringá (HUM).
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Response Factor in GC-FID Methyl Ester Analysis in Several Biodiesels: A Comparative Study of the EN 14103:2011 and ABNT 15764:2015 Methods versus a Proposed GC-FID Procedure for Individual Ester Determination
A gas chromatography method with a flame ionization detector enabled by relative response factor was developed to determine the individual and the total content of esters in biodiesel. This method accounts for different response factors of the detector for a homologous series of esters that may be present in biodiesel. In this way, the determination of the t
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. Atomic Absorption Spectrometry as an Alternative to Determine the Presence of Gold Nanoparticles on or in Silica Matrix
Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and
Journal of the Brazilian Chemical Society. Publicado em: 2022
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4. A Physical Study to Explain Response Differences between the BID and FID Detectors for PAHs and Pesticides
The dielectric barrier discharge ionization detector (BID) is one of the most modern detectors commercially available for gas chromatography (GC). Its technology based on the sample ionization through the energy released from the helium plasma generation process gives it the ability to act as a universal detector and a greater response to various types of co
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. Innovative gas chromatographic determination of formaldehyde by miniaturized extraction and on-fiber derivatization, via SPME and SPME Arrow
Formaldehyde (FA) is a carbonyl compound, ubiquitous in the environment and among the most widespread pollutants: it has exhibited toxic properties and is classified as a human carcinogen. FA is released from several sources, both temporary (e.g., combustion processes) and permanent (e.g., building products). This work proposes an innovative fully-automated
Química Nova. Publicado em: 2022
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6. Molecular Docking in silico Analysis of Brazilian Essential Oils Against Host Targets and SARS-CoV-2 Proteins
The inhibitory activity of thirty-one sesquiterpenes identified from Brazilian essential oils (Copaifera langsdorffii Desf., Croton cajucara Benth. and Siparuna guianensis Aublet.) were analyzed by in silico molecular docking. The compounds were characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame-ionization detecti
Journal of the Brazilian Chemical Society. Publicado em: 2022
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7. A Gas Chromatography Method for Simultaneous Quantification of Inorganic Gases and Light Hydrocarbons Generated in Thermochemical Processes
This paper reports a method for simultaneous determination of H2, O2, N2, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H4 (propadiene and propyne), C3H6, C3H8 and C4H10 (n-butane and isobutane) by gas chromatography using thermal conductivity and flame ionization detectors. A single porous layer open tubular column (0.53 mm internal diameter ? 30 m length ? 30 µm thic
J. Braz. Chem. Soc.. Publicado em: 2021-06
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8. Thallium Associated with Manganese Ore Tailings in a Deactivated Mine in the Western Region of Bahia, Brazil
Thallium (Tl) is a rare metal with toxic effects notably harmful to human health and the environment. In this article, the natural occurrence of Tl was evaluated in a deactivated manganese mine located in the western region of Bahia, Brazil. The extraction procedure with aqua regia was used to dissolve the soil, sediment, and tailings samples. The Tl content
J. Braz. Chem. Soc.. Publicado em: 2021-05
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9. Development and Validation of a Gas Chromatographic Method for the Quantification of Minor Alkaloids in Cocaine
The quantification of minor alkaloids in seized cocaine can provide information for drug profiling and law enforcement initiatives. This work presents the development and validation of an analytical method to quantitate minor alkaloids in cocaine samples using gas chromatography with flame ionization detector, after derivatization. The method was validated i
J. Braz. Chem. Soc.. Publicado em: 2021-04
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10. SEQUENTIAL MULTI-ELEMENT DETERMINATION OF TRACE-METALS IN BIODIESEL SAMPLES USING HR-CS FAAS
In this work the feasibility of sequential multi-element determination of Zn, Fe, Mg, Cu, Na, K, Cr, Al and Ca in biodiesel samples by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was investigated. Biodiesel samples obtained from different sources and different chemical processes were analysed. The samples were diluted w
Quím. Nova. Publicado em: 2021-02
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11. FATTY ACIDS ANALYSIS AND CHEMOTAXONOMIC CONSIDERATIONS OF MALVOIDEAE (MALVACEAE) SPECIES
Previous researches showed that fatty acids analysis might be a useful tool to support the taxonomic investigation. In this approach the fatty acids content of ten Malvoideae species was analyzed and its chemotaxonomic significance has been investigated. The aerial parts of the species were collected in the Northeast of Brazil and their fatty acid methyl est
Quím. Nova. Publicado em: 2021-02
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12. MAIN MINERALS AND ORGANIC COMPOUNDS IN COMMERCIAL ROASTED AND GROUND COFFEE: AN EXPLORATORY DATA ANALYSIS
Coffee is one of the most popular beverages in the world, however, little information is found regarding the mineral composition of commercial roasted and ground coffees (RG) and its correlation with organic bioactive compounds. 21 commercial Brazilian RG coffee brands - 9 traditional (T) and 12 extra strong (ES) roasted ones - were analyzed for the Cu, Ca,
Quím. Nova. Publicado em: 2021-01