Infrared Measurements
Mostrando 1-12 de 322 artigos, teses e dissertações.
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1. Thermal Infrared Enthalpimetry Method for the Determination of Hypochlorite in Bleaching Solutions
Thermal infrared enthalpimetry (TIE) was used for hypochlorite determination in commercial hypochlorite-based bleaching solutions. Experimental parameters were evaluated for the reaction with a hydrogen peroxide solution. The most relevant conditions were 5% H2O2 (m/m) solution, stirring speed of 250 rpm, dispensing rate of 0.57 mL s-1, and 10 s after reacti
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. New Greener Method for the Preparation of Heteropolyacid Compounds (HPW) Modified with Metallic Tin and Application in the Lactic Acid Esterification Reaction
The main objective of this work was to design an innovative method to prepare heterogeneous heteropolyacid catalysts. The heteropolyacid H3PW12O40 (HPW) was modified with tin(II) by two methodologies: a conventional aqueous ion-exchange (CS) and a redox solid-state (SS). In both cases, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD
J. Braz. Chem. Soc.. Publicado em: 2021-03
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3. SYNTHESIS, CHARACTERIZATION, DFT MODELING AND IN VITRO ANTIMYCOBACTERIAL ACTIVITY ASSAYS OF A SILVER(I)-ISONIAZID COMPLEX
In the present work, a silver(I) complex with the antimycobacterial drug isoniazid (inh) is described. Elemental and thermogravimetric analyses confirmed a 1:1 metal:ligand ratio for the silver-isoniazid (Ag-inh) complex with molecular composition AgC6H7N3O·NO3. Infrared (IR) analysis suggests a bidentate coordination of isoniazid to silver by the nitrogen
Quím. Nova. Publicado em: 2021-03
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4. Aqueous Extract of Cumaru (Dipteryx odorata) Seeds as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution
The corrosion inhibition of mild steel by aqueous extract of cumaru (Dipteryx odorata) seeds and its high molecular weight fraction (HMWF) was investigated in 1 mol L-1 HCl solution. The study was carried out through gravimetric essays, open circuit potential measurements, anodic and cathodic polarization curves and electrochemical impedance analyses, as wel
J. Braz. Chem. Soc.. Publicado em: 2021-02
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5. Hybrid Hydrogels Based on Polyethylene Glycol Bioconjugated with Silylated-Amyloidogenic Peptides
Hybrid-peptide hydrogel arrangements are a promising alternative to obtaining biocompatible structures at the nanoscopic scale. In this work, a new class of hybrid hydrogels was obtained through the sol-gel process based on the reaction between an amyloid-like octapeptide sequence [RF]4 (where R = arginine and F = phenylalanine) covalently bonded with glycin
J. Braz. Chem. Soc.. Publicado em: 2020-11
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6. Blue-Emitting MWO4:Tm3+ (M: Sr, Ba) Phosphors Prepared by Coprecipitation Method at Room Temperature
MWO4 host matrices (M: Sr, Ba) doped with different Tm3+ concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 mol%) have been successfully prepared by the coprecipitation method at room temperature. The as-prepared nanophosphors were characterized by infrared spectroscopy showing intense absorption bands in the range of 700-1000 cm-1 attributed to the symmetrical
J. Braz. Chem. Soc.. Publicado em: 2020-11
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7. STUDY OF SPECTROPHOTOMETRIC CHARACTERISTICS OF THE CHARGE TRANSFER COMPLEX OF TAURINE DRUG WITH 7,7,8,8-TETRACYANOQUINODIMETHANE
A new spectrophotometric method was developed for the determination of taurine using 7,7,8,8-tetracyanoquinodimethane (TCNQ). The method was based on the formation of charge transfer (CT) complex of this drug as n-electron donor with the π-acceptor TCNQ. TCNQ was found to react with taurine to produce a kind of yellow complex. The spectrum obtained for taur
Quím. Nova. Publicado em: 2020-09
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8. Investigation of the Relationship between Cerebral Near-Infrared Spectroscopy Measurements and Cerebrovascular Event in Coronary Artery Bypass Grafting Operation in Patients without Carotid Stenosis and Patients with Carotid Stenosis below Surgical Margins
Abstract Objectives: Stroke is an important cause of mortality and morbidity in surgery. In the present study, we examined the cerebral oximetry values of patients with carotid artery stenosis who did not present surgical indications and those who did not present carotid artery stenosis in coronary artery bypass grafting (CABG) surgery by comparing their ce
Braz. J. Cardiovasc. Surg.. Publicado em: 2020-08
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9. A New Isoflavone and Other Constituents from Roots of Clitoria guianensis
A new isoflavone named pratensein-7-O-β-D-rutinoside [(-)-7-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl-5,3’-dihydroxy-4’-methoxyisoflavone] and the known compounds biochanin A-7-O-β-D-rutinoside, 6-deoxyclitoriacetal 11-O-β-D-glucopyranoside, 6-deoxyclitoriacetal, (2S)-naringenin-6-C-β-D-glucopyranoside, (2R)-naringenin-6-C-β-D-glucopyranosi
J. Braz. Chem. Soc.. Publicado em: 2020-08
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10. Fast Verification of Buffalo’s Milk Authenticity by Mid-Infrared Spectroscopy, Analytical Measurements and Multivariate Calibration
Mid-infrared spectroscopy (MID), chemical composition and physicochemical characteristics associated with chemometrics were used to rapidly detect and quantify the amount of cow’s milk added in buffalo’s milk. A total of 165 samples, divided into buffalo’s milk, buffalo’s milk added with cow’s milk (10 to 90%) and cow’s milk were evaluated to obt
J. Braz. Chem. Soc.. Publicado em: 2020-07
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11. Aqueous Extracts of the Castor Beans as a Corrosion Inhibitor of Mild Steel in HCl Media
The present work studied aqueous extracts of castor beans as a natural inhibitor of the corrosion of mild steel in 1 M HCl using gravimetric tests, potentiodynamic polarization curves, linear polarization method, electrochemical impedance measurements, surface analysis by scanning electron microscopy (SEM) and chemical characterization by Fourier transform i
J. Braz. Chem. Soc.. Publicado em: 2020-06
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12. Thermal Infrared Enthalpimetry in Paper Microzone Plates for Green and High Throughput Determination of Wine Acidities
The use of paper devices in chemical analysis has been increased due to their low cost, high surface area, portability, and biodegradability. A novel use of paper devices is proposed using thermal infrared enthalpimetry (TIE) for a rapid, green, and high throughput determination of wine acidities. The determination of total, fixed, and volatile acidities in
J. Braz. Chem. Soc.. Publicado em: 2020-02