scholarly journals Structural Study of Wheat Gliadin in Different Solvents by Spectroscopic Techniques

2021 ◽  
Author(s):  
Andresa Ribeiro ◽  
Daiani Leite ◽  
Jóice Scheibel ◽  
Rosane Soares ◽  
Nádya Silveira
Keyword(s):  
Size Distribution ◽  
Protein Unfolding ◽  
Aqueous Ethanol ◽  
Attenuated Total Reflectance ◽  
Spectroscopic Techniques ◽  
Protein Conformations ◽  
Unstable System ◽  
Wheat Gliadin ◽  
Solvent Systems ◽  
Lower Size

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) showed a lower size distribution, whereas samples solubilized in 60% aqueous ethanol presented a lower size distribution only at pH 1.2. ZP analysis showed that gliadin-H2O (pH 9.8) was the most stable evaluated system. ZP results of gliadin-DMSO indicated an unstable system, with the coexistence of several protein conformations. ATR-FTIR analysis showed that, in H2O, most protein conformations were β-sheets, while in DMSO a band at 1660 cm−1 appeared to be related to protein unfolding. The techniques proved to be effective in monitoring conformation and stability of all gliadin/solvent systems. Such information can be used in the development of new gliadin-based materials.

Near-infrared and Mid-infrared Spectroscopic Techniques for a Fast and Nondestructive Quality Control of Thymi herba

Planta Medica ◽  
2017 ◽  
Vol 84 (06/07) ◽  
pp. 420-427 ◽  
Author(s):  
Cornelia Pezzei ◽  
Stefan Schönbichler ◽  
Shah Hussain ◽  
Christian Kirchler ◽  
Verena Huck-Pezzei ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Rosmarinic Acid ◽  
Near Infrared ◽  
Coefficient Of Determination ◽  
Attenuated Total Reflectance ◽  
Spectroscopic Techniques ◽  
Test Set ◽  
Mid Infrared ◽  
Capacity Coefficient ◽  
Infrared Spectroscopic

AbstractIn this study, novel near-infrared and attenuated total reflectance mid-infrared spectroscopic methods coupled with multivariate data analysis were established enabling the determination of thymol, rosmarinic acid, and the antioxidant capacity of Thymi herba. A new high-performance liquid chromatography method and UV-Vis spectroscopy were applied as reference methods. Partial least squares regressions were carried out as cross and test set validations. To reduce systematic errors, different data pretreatments, such as multiplicative scatter correction, 1st derivative, or 2nd derivative, were applied on the spectra. The performances of the two infrared spectroscopic techniques were evaluated and compared. In general, attenuated total reflectance mid-infrared spectroscopy demonstrated a slightly better predictive power (thymol: coefficient of determination = 0.93, factors = 3, ratio of performance to deviation = 3.94; rosmarinic acid: coefficient of determination = 0.91, factors = 3, ratio of performance to deviation = 3.35, antioxidant capacity: coefficient of determination = 0.87, factors = 2, ratio of performance to deviation = 2.80; test set validation) than near-infrared spectroscopy (thymol: coefficient of determination = 0.90, factors = 6, ratio of performance to deviation = 3.10; rosmarinic acid: coefficient of determination = 0.92, factors = 6, ratio of performance to deviation = 3.61, antioxidant capacity: coefficient of determination = 0.91, factors = 6, ratio of performance to deviation = 3.42; test set validation). The capability of infrared vibrational spectroscopy as a quick and simple analytical tool to replace conventional time and chemical consuming analyses for the quality control of T. herba could be demonstrated.

scholarly journals Efficient removal of three dyes using porous covalent triazine frameworks: adsorption mechanism and role of pore distribution

2020 ◽  
Vol 82 (12) ◽  
pp. 3023-3031
Author(s):  
Fengxia An ◽  
Jingliang Liu ◽  
Zhaoyi Xu ◽  
Shourong Zheng
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Ph Dependence ◽  
Batch Adsorption ◽  
Spectroscopic Techniques ◽  
Adsorption Mechanisms ◽  
Bonding Interaction ◽  
Adsorption Affinity

Abstract Dyes are widely used in production and life. In this study, porous covalent triazine frameworks (CTFs) were synthesized and the adsorption behavior for three dyes was investigated by batch adsorption experiments. CTFs were characterized by various spectroscopic techniques for structure, porosity and surface properties. Several possible adsorption mechanisms were proposed including pore-filling, electrostatic attraction and hydrogen bonding interaction with the triazine structure of CTFs. The mechanisms were further verified by the pore size distribution and pH dependence. Additionally, CTFDCBP displayed stronger adsorption affinity and faster adsorption kinetics for dyes, because of the wide pore size distribution. This study provides a new insight into the mesoporous CTFs, which exhibit great potential as an effective adsorbent for dye removal.

Thermodynamics of Ionization of Nitroethane in Water–Ethanol Solvent Mixtures

1974 ◽  
Vol 52 (10) ◽  
pp. 1910-1913 ◽  
Author(s):  
Takeki Matsui ◽  
Loren G. Hepler ◽  
Earl M. Woolley
Keyword(s):  
Mixed Solvent ◽  
Aqueous Ethanol ◽  
Equilibrium Constants ◽  
Glass Electrode ◽  
Solvent Mixtures ◽  
Calorimetric Measurements ◽  
Solvent Systems ◽  
Ionization Of Water ◽  
Thermodynamics Of Ionization ◽  
Acid Ionization

We have made glass electrode measurements that lead to values for the equilibrium constant for acid ionization of nitroethane in water and in aqueous ethanol mixed solvent systems. Calorimetric measurements have led to ΔH0 values for the acid ionization of nitroethane in water and in aqueous ethanol. These results have been combined to yield TΔS0 values for the ionization reactions in water and in aqueous ethanol. Our results have also been combined with previously reported equilibrium constants for ionization of water in aqueous ethanol to obtain thermodynamic data for the neutralization of nitroethane in the various solvent systems.

scholarly journals Isolation of 2, 5-dithia-3, 6-diazabicyclo [2.2.1] heptane and GC-MS analysis of silylated extract from Tragia benthamii

2020 ◽  
Vol 22 (2) ◽  
pp. 075-080
Author(s):  
O.S. Balogun ◽  
I.A. Oladosu ◽  
Zhiqiang Liu
Keyword(s):  
Secondary Metabolites ◽  
Aqueous Ethanol ◽  
Chemical Constituents ◽  
Dry Weight ◽  
Spectroscopic Techniques ◽  
Chromatographic Purification ◽  
Pure Compound ◽  
Ms Analysis ◽  
First Time ◽  
Derivatives Of

Tragia benthamii is a medicinal plant of repute endemic in West Africa. However, despite the traditional uses of the plant its secondary metabolites are yet to be profiled. Thus, this study aimed at identifying the chemical  constituents of T. benthamii. Air-dried samples (600 g) of the plant were extracted with aqueous ethanol (95 %) and thereafter, portions of the crude extract obtained were used separately for chromatographic  purifications, GC-MS analysis and spectrophotometric quantitation of the secondary metabolites. The chromatographic purification of the extract afforded a pure compound elucidated as 2,5-dithia-3,6-diazabicyclo [2.2.1] heptane using spectroscopic techniques. Upon silylation and GC-MS analysis of the extract, derivatives of sugar (34.65%), fatty acids (24.11%) and phytol (21.00%) were identified as principal constituents. Also, a total of 6.25 mg rutin/g, 5.18 mg ginsenoside/g and 6.84 mg glucose/g dry weight sample were obtained for flavonoids, saponins and carbohydrate, respectively from the spectrophotometric quantitation. These secondary metabolites are being reported for the first time from this plant. Keywords: Tragia benthamii; secondary metabolites; quantitative analysis; silylation

scholarly journals Analysis of ‘legal high’ substances and common adulterants using handheld spectroscopic techniques

2015 ◽  
Vol 7 (2) ◽  
pp. 736-746 ◽  
Author(s):  
S. Assi ◽  
A. Guirguis ◽  
S. Halsey ◽  
S. Fergus ◽  
J. L. Stair
Keyword(s):  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Near Infrared ◽  
Fourier Transform Infrared ◽  
Attenuated Total Reflectance ◽  
Spectroscopic Techniques ◽  
Total Reflectance ◽  
Legal High ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Three handheld spectrometers, near-infrared (NIR), Raman and attenuated total reflectance Fourier transform-infrared (ATR-FT-IR) spectroscopy, were used for the identification of ‘legal high’ model mixtures and Internet products.

Characterization of Conversion-Coated Aluminum Using Fourier Transform Infrared and Raman Spectroscopies

1992 ◽  
Vol 46 (9) ◽  
pp. 1412-1419 ◽  
Author(s):  
Angela M. Ahern ◽  
Paul R. Schwartz ◽  
Lori A. Shaffer
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Attenuated Total Reflectance ◽  
Spectroscopic Techniques ◽  
Conversion Coatings ◽  
Total Reflectance ◽  
Raman Spectroscopic ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Chromium Phosphate

Fourier transform infrared and Raman spectroscopies have been employed to define the molecular composition of chromium phosphate conversion coatings on aluminum. Attenuated total reflectance at 55° can be employed to probe the structure of conversion coatings present on aluminum at relatively high coating weights (≥23 mg Cr/m2). Both reflection-absorption infrared and surface-enhanced Raman spectroscopic techniques can discern the presence of conversion coatings at coverages as low as 9 mg Cr/m2. On the basis of the vibrational spectra from these techniques, we have determined that hydrated chromium phosphate is the major component in these conversion coatings on aluminum. Reflection-absorption infrared and surface-enhanced Raman spectroscopies also provide a means to determine the molecular structure of the nascent oxide layer on aluminum as a function of processing conditions. Specular reflection, attenuated total reflectance at 35°, diffuse reflectance, and Raman spectroscopic methods, in general, lack the surface sensitivity necessary to probe thin (≤23 mg/m2) inorganic films on aluminum.

Drug-Excipients Compatibility Studies in Proniosomal Formulation: A Case Study with Resveratrol

2021 ◽  
Vol 21 (5) ◽  
pp. 2917-2921
Author(s):  
Michele Schlich ◽  
Francesco Lai ◽  
Anna Maria Fadda ◽  
Chiara Sinico ◽  
Elena Pini
Keyword(s):  
Attenuated Total Reflectance ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Study ◽  
Spectroscopic Techniques ◽  
Compatibility Studies ◽  
X Ray Diffraction ◽  
Total Reflectance ◽  
X Ray ◽  
Excipient Compatibility

Proniosomal drug delivery system is one of the advancements in nanotechnology. Similarly to traditional dosage forms, chemical and physical compatibility of proniosomes components with the active ingredient(s) is a key step in the preformulation process of such systems. In this work, the compatibility of resveratrol with selected excipients in the development of proniosomal formulation was investigated by thermal and spectroscopic techniques. To evaluate the drug-excipient compatibility, different techniques such as differential scanning calorimetric study, attenuated total reflectance Fourier transform infrared spectroscopy study and powder X-ray diffraction were adopted. The results showed that the excipients used in the formulation were compatible with resveratrol.

scholarly journals Comparison of photoacoustic, diffuse reflectance, attenuated total reflectance and transmission infrared spectroscopy for the study of biochars

2018 ◽  
Vol 20 (4) ◽  
pp. 75-83 ◽  
Author(s):  
Sylwia Pasieczna-Patkowska ◽  
Jarosław Madej
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Diffuse Reflectance ◽  
Pyrolysis Temperature ◽  
Attenuated Total Reflectance ◽  
Signal Acquisition ◽  
Spectroscopic Techniques ◽  
Spectral Quality ◽  
Total Reflectance ◽  
Ft Ir

Abstract Four infrared spectroscopic techniques - photoacoustic (PAS), diffuse reflectance (DRS), attenuated total reflectance (ATR) and transmission (TS) - were evaluated for the qualitative analysis of the biochar obtained from willow feedstock during pyrolysis. Increase in pyrolysis temperature resulted in more aromatic and carbonaceous structure of biochars. These changes could easily be detected from Fourier transform infrared (FT-IR) spectral differences. The comparison of the spectra obtained by the four FT-IR techniques allowed to conclude that there are differences in the spectra acquired using different IR technique caused by different signal acquisition. PAS and ATR were the best techniques used in order to obtain spectra with smooth and sharp peaks, in contrast to TS, where bands were less-separated. DRS turned out to be the weakest of all techniques, due to poor spectral quality and poor separation of the bands.

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