Analysis of 5-hydroxytryptophan in the presence of excipients from dietary capsules: comparison between cyclic voltammetry and UV visible spectroscopy

2013 ◽  
Vol 5 (10) ◽  
pp. 2523 ◽  
Author(s):  
Isabel J. Tunna ◽  
Bhavik Anil Patel
Keyword(s):  
Cyclic Voltammetry ◽  
Visible Spectroscopy ◽  
Uv Visible

scholarly journals Novel NiMgOH-rGO-Based Nanostructured Hybrids for Electrochemical Energy Storage Supercapacitor Applications: Effect of Reducing Agents

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1144
Author(s):  
Konda Shireesha ◽  
Thida Rakesh Kumar ◽  
Tumarada Rajani ◽  
Chidurala Shilpa Chakra ◽  
Murikinati Mamatha Kumari ◽  
...  
Keyword(s):  
Particle Size ◽  
Cyclic Voltammetry ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Uv Visible

This paper describes the synthesis and characterization of NiMgOH-rGO nanocomposites made using a chemical co-precipitation technique with various reducing agents (e.g., NaOH and NH4OH) and reduced graphene oxide at 0.5, 1, and 1.5 percent by weight. UV-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, a particle size analyzer, and cyclic voltammetry were used to characterize the composite materials. The formation of the NiMgOH-rGO nanocomposite with crystallite sizes in the range of 10–40 nm was inferred by X-ray diffraction patterns of materials, which suggested interlayers of Ni(OH)2 and Mg(OH)2. The interactions between the molecules were detected using Fourier-transform infrared spectroscopy, while optical properties were studied using UV-visible spectroscopy. A uniform average particle size distribution in the range of 1–100 nm was confirmed by the particle size analyzer. Using cyclic voltammetry and galvanostatic charge/discharge measurements in a 6 M KOH solution, the electrochemical execution of NiMgOH-rGO nanocomposites was investigated. At a 1 A/g current density, the NiMgOH-rGO nanocomposites prepared with NH4OH as a reducing agent had a higher specific capacitance of 1977 F/g. The electrochemical studies confirmed that combining rGO with NiMgOH increased conductivity.

Syntheses and optoelectronic properties of amino/carboxyphenylporphyrins for potential use in dye-sensitized TiO2 solar cells

2007 ◽  
Vol 11 (08) ◽  
pp. 601-612 ◽  
Author(s):  
Michael G. Walter ◽  
Carl C. Wamser ◽  
Joseph Ruwitch ◽  
Yinping Zhao ◽  
Dale Braden ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solar Cell ◽  
Polyphosphoric Acid ◽  
Hydroxylamine Hydrochloride ◽  
Visible Spectroscopy ◽  
Dye Sensitized ◽  
Product Distributions ◽  
Synthetic Routes ◽  
Uv Visible ◽  
Potential Use

New mixed-substituent amino/carboxyphenylporphyrins for a dye-sensitized TiO 2 solar cell were prepared using several synthetic routes. The reaction of 4-carbomethoxy- and 4-acetamidobenzaldehydes with pyrrole in propionic acid under aerobic conditions afforded mixtures of mixed amide/ester substituted tetraphenylporphyrins which were separated using centrifugal chromatography then deprotected to give the target compounds. Condensation of p-nitrophenyldipyrromethane with 4-carbomethoxybenzaldehyde in CH 2 Cl 2 catalyzed by trifluoroacetic acid, followed by oxidation with dichlorodicyanoquinone gives trans-dicarbomethoxy/dinitrophenylporphyrin, which when treated with SnCl 2 and HCl affords the trans-diamino/dicarboxy derivative, trans- TA 2 C 2 PP . Commercially available tetrakis-5,10,15,20-(4-carboxyphenyl)porphyrin (TCPP) was converted to mixtures of mixed amino/carbomethoxyphenylporphyrins using hydroxylamine hydrochloride in polyphosphoric acid with methanol workup. Relative yields and product distributions from each route are discussed and the optoelectronic characteristics of the synthesized porphyrins were studied using UV-visible spectroscopy and cyclic voltammetry.

Synthesis and electrochemical investigation of covalently linked porphyrin dimers containing a β-brominated subunit.

2003 ◽  
Vol 07 (09) ◽  
pp. 595-609 ◽  
Author(s):  
Zhongping Ou ◽  
Pietro Tagliatesta ◽  
Mathias O. Senge ◽  
Jianguo Shao ◽  
Karl M. Kadish
Keyword(s):  
Cyclic Voltammetry ◽  
Single Crystal ◽  
Electrochemical Investigation ◽  
Visible Spectroscopy ◽  
Electronic Interactions ◽  
X Ray ◽  
Uv Visible ◽  
Covalently Linked ◽  
Porphyrin Dimers

Ten meso-tetraphenylporphyrin-type heterodimers containing a partly or completely β-brominated subunit were synthesized and characterized by UV-visible spectroscopy, cyclic voltammetry and spectroelectrochemistry, showing the presence of low electronic interactions between the two subunits. The investigated compounds are represented as M [( tripp - tpp ( Br 4)] M and M [ tripp - tpp ( Br 8)] M ( M = 2 H , Zn , Ni , Co and Cu ) where tripp - tpp ( Br 4) is the tetraanion of 1-[5-(10,15,20-triphenylporphyrinyl)]-4-[10-(2,3,12,13-tetrabromoporphyrinyl)]-benzene and tripp - tpp ( Br 8) is the tetraanion of 1-[5-(10,15,20-triphenylporphyrinyl)]-4-[10-(2,3,7,8,12,13,17,18-octabromoporphyrinyl)]-benzene. One of the synthesized dimers, H 2[ tripp - tpp ( Br 8)] H 2, was characterized by a single-crystal X-ray investigation.

Characterization of Mammea A/AA in solution and in interaction with β-cyclodextrin: UV–visible spectroscopy, cyclic voltammetry and DFT-TDDFT/MD study

2016 ◽  
Vol 213 ◽  
pp. 294-303 ◽  
Author(s):  
Baruch A. Ateba ◽  
Daniel Lissouck ◽  
Anatole Azébazé ◽  
Christophe Thiery Ebelle ◽  
Achille Nassi ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Visible Spectroscopy ◽  
Uv Visible

Difunctionalized N-Confused Porphyrins: Synthesis, Fluorescence, and Electrochemical Studies

2015 ◽  
Vol 68 (6) ◽  
pp. 896 ◽  
Author(s):  
Sudipta Das ◽  
Naresh Balsukuri ◽  
Praseetha E. Kesavan ◽  
Iti Gupta
Keyword(s):  
Mass Spectrometry ◽  
Cyclic Voltammetry ◽  
Infrared Spectroscopy ◽  
High Resolution Mass Spectrometry ◽  
Electrochemical Studies ◽  
Visible Spectroscopy ◽  
Fluorescence Studies ◽  
Uv Visible ◽  
Stokes Shifts ◽  
Resolution Mass

Seven di-substituted N-confused porphyrins (NCPs) 9–15 bearing two aryl functional groups (cis-A2B2 type) were synthesized in 4–7 % yields via [3+1] approach. The corresponding five 5,10-diaryl-substituted symmetrical tripyrranes 1–5 were prepared and condensed with 2,4-bis(hydroxypentaflurophenyl)pyrrole 6. Two outer N-methyl type A2B2 NCPs 14 and 15 were also prepared via a similar approach using a new key precursor 8. All the porphyrins 9–15 were characterized by high-resolution mass spectrometry, NMR, infrared spectroscopy, UV–visible spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. Fluorescence studies of 9–15 showed blue-shifted emission maxima and lower Stokes shifts values when compared with N-confused tetraphenylporphyrin (NCTPP). Electrochemical studies indicated easier oxidation of N-methyl NCPs 14 and 15 when compared with remaining NCPs 9–13.

Biocompatibility of Silver Nano Bio-conjugates from Vitis vinifera Seeds and its Major Component Resveratrol

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
R. Preethi ◽  
P. Padma
Keyword(s):  
Zeta Potential ◽  
Vitis Vinifera ◽  
Silver Ions ◽  
Seed Extract ◽  
Polydispersity Index ◽  
Potential Range ◽  
Visible Spectroscopy ◽  
Grape Seeds ◽  
X Ray ◽  
Uv Visible

The study focused on the green synthesis of silver nanobioconjugates (AgNPs) from phenolic-rich fruit source, Vitis vinifera seed extract and its major component phenolic, resveratrol respectively. Sunlight exposure for 20 minutes was the method of choice for the synthesis of AgNPs of the extract as well as the phenolic, resveratrol. The synthesized nanobioconjugates were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), Polydispersity index, Zeta potential and Fourier transform infrared spectroscopy (FTIR). The reduction of silver ions was confirmed by UV-visible spectroscopy with peaks at 440nm for both nanobioconjugates synthesized from seed extract and compound. The nanobioconjugates showed the spherical in shape with 14-35nm in size and crystalline in nature. The conjugates are well dispersed with 0.301 and 0.287 polydispersity index and the zeta potential range at -13.6 and -14.3mV for stability. The FTRI data proved that the components in grape seeds act as good reductants and stabilizers for the silver nanobioconjugate synthesis. All the synthesized nanobioconjugates exhibited steady and sustained release of the medicinal components conjugated, proving their druggability, and were biocompatible with human cells, demonstrating their safety. The findings of the study validate the anticancer properties of silver nanobioconjugates of Vitis vinifera and its active component resveratrol.

Evaluation of Antibacterial and Antidiabetic Potential of Silver Nanoparticles using Eugenia Uniflora L. Seed Extract

2020 ◽  
Vol 13 (6) ◽  
pp. 5217-5225
Author(s):  
Guru Kumar Dugganaboyana ◽  
Chethankumar Mukunda ◽  
Suresh Darshini Inakanally
Keyword(s):  
Biomedical Applications ◽  
Pathogenic Bacteria ◽  
Seed Extract ◽  
Drug Formulation ◽  
Visible Spectroscopy ◽  
Plant Materials ◽  
X Ray ◽  
Eugenia Uniflora ◽  
Uv Visible

In recent years, green nanotechnology-based approaches using plant materials have been accepted as an environmentally friendly and cost-effective approach with various biomedical applications. In the current study, AgNPs were synthesized using the seed extract of the Eugenia uniflora L. (E.uniflora). Characterization was done using UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The formation of AgNPs has confirmed through UV-Visible spectroscopy (at 466 nm) by the change of color owing to surface Plasmon resonance. Based on the XRD pattern, the crystalline property of AgNPs was established. The functional group existing in seed of E.uniflora extract accountable for the reduction of Ag+ ion and the stabilization of AgNPs was investigated. The morphological structures and elemental composition was determined by SEM and EDX analysis. With the growing application of AgNPs in biomedical perspectives, the biosynthesized AgNPs were evaluated for their antibacterial and along with their antidiabetic potential. The results showed that AgNPs are extremely effective with potent antidiabetic potential at a very low concentration. It also exhibited potential antibacterial activity against the three tested human pathogenic bacteria. Overall, the results highlight the effectiveness and potential applications of AgNPs in biomedical fields such as in the treatment of acute illnesses as well as in drug formulation for treating various diseases such as cancer and diabetes. It could be concluded that E. uniflora seed extract AgNPs can be used efficiently for in vitro evaluation of their antibacterial and antidiabetic effects with potent biomedical applications.

scholarly journals Polymer Composites with 0.98 Transparencies and Small Optical Energy Band Gap Using a Promising Green Methodology: Structural and Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1648
Author(s):  
Muaffaq M. Nofal ◽  
Shujahadeen B. Aziz ◽  
Jihad M. Hadi ◽  
Wrya O. Karim ◽  
Elham M. A. Dannoun ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Polymer Composites ◽  
Amorphous Phase ◽  
Absorption Edge ◽  
Complex Form ◽  
Bandgap Energy ◽  
Optical Parameters ◽  
Visible Spectroscopy ◽  
Uv Visible

In this work, a green approach was implemented to prepare polymer composites using polyvinyl alcohol polymer and the extract of black tea leaves (polyphenols) in a complex form with Co2+ ions. A range of techniques was used to characterize the Co2+ complex and polymer composite, such as Ultraviolet–visible (UV-Visible) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The optical parameters of absorption edge, refractive index (n), dielectric properties including real and imaginary parts (εr, and εi) were also investigated. The FRIR and XRD spectra were used to examine the compatibility between the PVA polymer and Co2+-polyphenol complex. The extent of interaction was evidenced from the shifts and change in the intensity of the peaks. The relatively wide amorphous phase in PVA polymer increased upon insertion of the Co2+-polyphenol complex. The amorphous character of the Co2+ complex was emphasized with the appearance of a hump in the XRD pattern. From UV-Visible spectroscopy, the optical properties, such as absorption edge, refractive index (n), (εr), (εi), and bandgap energy (Eg) of parent PVA and composite films were specified. The Eg of PVA was lowered from 5.8 to 1.82 eV upon addition of 45 mL of Co2+-polyphenol complex. The N/m* was calculated from the optical dielectric function. Ultimately, various types of electronic transitions within the polymer composites were specified using Tauc’s method. The direct bandgap (DBG) treatment of polymer composites with a developed amorphous phase is fundamental for commercialization in optoelectronic devices.

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