Spectroscopic Techniques
Mostrando 1-12 de 274 artigos, teses e dissertações.
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1. 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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2. DITERPENOS ENT-ABIETANOS DE Euphorbia phosphorea (EUPHORBIACEAE)
Phytochemical study of the roots of Euphorbia phosphorea Mart. (Euphorbiaceae) was carried out through chromatographic techniques, resulting in the isolation of a new ent-abietane diterpene named 11β,12β-dihydroxy-ent-abieta-8(14),13(15)-dien-16,12α-olide (1), and of nine known ent-abietane diterpenes jolkinolide A (2), jolkinolide E (3), euphorin H (4),
Química Nova. Publicado em: 2022
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3. Reduced Graphene Oxide/Ruthenium Oxide Hexacyanoferrate Nanocomposite for Electrochemical Determination of Ethanol in Commercial Samples
Reduced graphene oxide/ruthenium oxide hexacyanoferrate (rGO/RuOHCF) modified electrode showed synergic activity between the materials attested by the increase of electrochemical current and stability. The preparation of the nanocomposite was made by a simple two-step electrochemical approach. The material structure was characterized by spectroscopic techniq
J. Braz. Chem. Soc.. Publicado em: 2021-06
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4. Individuals with untreated psychiatric disorders and suicide in the COVID-19 era
Reduced graphene oxide/ruthenium oxide hexacyanoferrate (rGO/RuOHCF) modified electrode showed synergic activity between the materials attested by the increase of electrochemical current and stability. The preparation of the nanocomposite was made by a simple two-step electrochemical approach. The material structure was characterized by spectroscopic techniq
Braz. J. Psychiatry. Publicado em: 2021-06
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5. Increased depression and anxiety during the COVID-19 pandemic in Brazilian mothers: a longitudinal study
Reduced graphene oxide/ruthenium oxide hexacyanoferrate (rGO/RuOHCF) modified electrode showed synergic activity between the materials attested by the increase of electrochemical current and stability. The preparation of the nanocomposite was made by a simple two-step electrochemical approach. The material structure was characterized by spectroscopic techniq
Braz. J. Psychiatry. Publicado em: 2021-06
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6. New Pair of 2-Amino-naphthoxazoles Derived from β-Lapachone: Synthesis, Spectral Evaluation and Crystal Structure
This work describes a novel synthetic route for obtaining 2-amino-naphthoxazoles derived from β-lapachone, which consists of a condensation reaction between β-lapachone and thiourea in a basic medium. This synthetic approach can be seen as a potential route for obtaining 2-amino-oxazoles from quinones. The obtained amino-naphthoxazoles were characterized b
J. Braz. Chem. Soc.. Publicado em: 2021-05
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7. Structural Study of Wheat Gliadin in Different Solvents by Spectroscopic Techniques
Physicochemical properties of gliadin in different solvents (dimethyl sulfoxide (DMSO), H2O, and aqueous ethanol) and pH (9.8, 6.8, and 1.2) were investigated using dynamic light scattering (DLS), zeta potential (ZP), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Gliadin-DMSO and gliadin-deionized water (H2O) (pH 9.8) s
J. Braz. Chem. Soc.. Publicado em: 2021-04
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8. A Symmetrical Dirhenium(I) Complex with 4,4’’-Azobis(2,2’-bipyridine) as a Bridging Ligand: Synthesis, Physicochemical Properties and Applications in Detection of Biologically Relevant Thiols and in Chemotherapy for Bone Cancer
A new dinuclear complex of formula [{Re(CO)3(py)}2(µ-4,4”-azobpy)](PF6)2, with py = pyridine and 4,4”-azobpy = 4,4”-azobis(2,2’-bipyridine), has been synthesized and characterized by spectroscopic and electrochemical techniques. The symmetrical nature of the dimetallic cation has been confirmed by nuclear magnetic resonance (NMR) measurements. When
J. Braz. Chem. Soc.. Publicado em: 2020-11
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9. TÉCNICAS AVANÇADAS PARA A DIFERENCIAÇÃO DE ISÔMEROS POR ESPECTROMETRIA DE MASSAS
Mass spectrometry (MS) is a powerful and widespread technique but is inherently uncapable to differentiate species with same m/z ratio. For this reason, many classical approaches were developed based on differential fragmentation patterns in tandem MS. More recently, new techniques for isomer identification in MS were developed, and we highlight the photodis
Quím. Nova. Publicado em: 2020-09
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10. Antibacterial Activity of 2-Amino-1,4-naphthoquinone Derivatives against Gram-Positive and Gram-Negative Bacterial Strains and Their Interaction with Human Serum Albumin
A series of 2-amino-1,4-naphthoquinone derivatives (NQA-NQF) was synthesized by alternative methods (ultrasonication and microwave irradiation), with yields ranging from 40 to 71%, and without the need of further recrystallization. Each compound was evaluated against four Gram-positive (Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus and Baci
J. Braz. Chem. Soc.. Publicado em: 2020-09
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11. Theoretical and Experimental Investigations on Inclusion Complex β-Cyclodextrin and Sulcatone: A Cardiovascular Activity Evaluation
In this paper, we have applied state-of-the-art technologies and new investigations were developed focusing on obtaining simple and inexpensive molecules for treating cardiovascular diseases, as they are considered the leading cause of death in the world. For the first time, the inclusion complex of sulcatone (SU) and β-cyclodextrin (β-CD) was achieved (us
J. Braz. Chem. Soc.. Publicado em: 2020-05
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12. ANÁLISE ESPECTROSCÓPICA DA MATÉRIA ORGÂNICA NO SEDIMENTO SUPERFICIAL DA BAÍA DE SEPETIBA, RIO DE JANEIRO, BRASIL
Spectroscopic techniques are powerful tools for molecular organic matter assessment in sediments, which analysis request low sample mass and are cheap, fast and easy to obtain. The aim of this work was to evaluate the elemental (C, N) and molecular composition of the organic matter in relation to the grain-size distribution over surface sediments from Sepeti
Quím. Nova. Publicado em: 2020-05