Ultraviolet-visible Spectroscopy Method Research Articles

Synthesis, nanostructuring and in silico studies of a new imine bond containing a macroheterocycle as a promising PBP-2a non-β-lactam inhibitor.

This study is devoted to the synthesis of a 40-membered macroheterocycle with its further nanostructuring by magnetite nanoparticles. The mentioned macroheterocycle was synthesized by the [2+2] cyclocondensation of the oxygen-containing diamine with an aromatic dialdehyde in a non-catalytic medium and with no work-up procedure. The structure of the obtained macroheterocycle was studied by 1H and 13C nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Furthermore, the nanosupramolecular complex of macroheterocycles with magnetite nanoparticles was obtained and investigated by Fourier-transform infrared and ultraviolet-visible spectroscopy methods. Shifts in the infrared spectra of the nanosupramolecular complex indicate the interaction through metal-aromatic ring non-covalent bonding. The shift is also observed for the C-O-C stretching band of ether bonds. The loading rate of macroheterocycles on magnetite nanoparticles was 18.6%. The morphology of the ensemble was studied by transmission electron microscopy, which confirmed the synthesis of nanospherical particles with a diameter range of 10-20 nm. Powder X-ray diffraction analysis showed patterns of cubic Fe3O4 nanoparticles with a crystallite size equal to 9.1 nm. The macroheterocycle and its nanosupramolecular complex were tested against Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. The results have shown that the created complex has shown 64 times better activity against Staphylococcus aureus in comparison with the individual macroheterocycle and 32 times better activity in comparison with the pristine antibiotic Ampicillin as a control. In addition, computational analysis of the macroheterocycle was performed at the B3LYP/6-31G level in water. Molecular docking analyses for the macroheterocycle revealed Penicillin-binding protein PBP2a (5M18) from the transpeptidase family as a target protein in Staphylococcus aureus.

PENGARUH GUGUS FUNGSI CINCIN PIRIDIN, BENZEN, DAN ATOM NITROGEN PADA CINCIN PIRIDIN TERHADAP PENURUNAN KADAR PLASMA PIRIDOKSIN TIKUS WISTAR

In this study, researchers will conduct further studies to determine the map of functional groups that have an affinity for neuropathy-causing enzymes in the pyridine ring functional group after previous research on pyridine ring substituents. Through this study, it will be known whether there is an effect of the N atom on the pyridine ring, and the structure of the benzene ring. Therefore, the three structures, namely benzohydrazide, butyrohydrazide, formohydrazide, and isoniazid control, will be tested for their effect on the inhibition of the pyridoxal phosphokinase enzyme in experimental rats to see the effect of changing functional groups on decreasing affinity for the pyridoxal phosphokinase enzyme receptor which can be indicated by a decrease in active pyridoxine levels in the blood. mouse. The three compound structures were then examined for their interactions with the pyridoxal phosphokinase enzyme through their effect on increasing levels of pyridoxal 5 phosphate which is the active form of pyridoxine, using the Ultraviolet-Visible Spectroscopy method which showed an accumulation of enzyme analog substrates from the three compound structures with substrates from the body. The results of the ultraviolet-visible spectroscopy test showed that the active pyridoxine levels of rats in the isoniazid, benzohydrazid, and formohydrazid groups and the negative control group were 160,259, 120,548, 107,086 and 104,490, respectively. Based on the results, it was concluded that benzohydrazide and formohydrazide did not have a pharmacophore group against the pyridoxine phosphokinase enzyme.

Growth Time Influence on Optical and Electrical Properties of TiO2 Nanorods Prepared via Hydrothermal Method

On a fluorine doped tin oxide (F: SnO2) coated glass substrate, TiO2 nanorod arrays (NRAs) were produced, successfully generated hydrothermally with an extended period of time (4, 6, 10, 20 and 30 h). Growth time and their effects on, morphological, structural, optical, and electrical characteristics of Titanium dioxide nanorods (NRs) were investigated by, Field Emission Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared spectroscopy and ultraviolet-visible spectroscopy methods. X-ray diffraction revealed the development of TiO2 nanorods in the tetragonal rutile structure of the produced TiO2 NRs with the maximum (002) peak strength. NRs had a tetragonal shape with square top facets, according to images showed by a Field-Emission Scanning Electron Microscope (FESEM). The range of nanorods’ diameter were detected to be (40.05-225.26) nm, respectively based on FESEM measurements. While Fourier Transform Infrared spectroscopy (FT-IR) showed a wide, band about 2952 cm-1. TiO2 NRs’ optical and electrical characteristics have been investigated. According to optical absorption tests, there was no discernible change in band distance with increasing growth time. For TiO2 nanorods primed with 4, 6, 10, 20 and 30 hours of reaction period, the band gap energy was found to be 3.14, 3.0, 3.12, 3.1, and 3.09 eV. The value of the energy gap reduced as reaction time increased from 4 to 30 hours, then increased as reaction time increased.

Effects of preparation temperature on production of graphene oxide by novel chemical processing

The effect of preparation temperature on the synthesis of high quality graphene oxide (GO) by a chemical oxidation method has been studied. GO samples have been produced from graphite using a blend of sulfuric and phosphoric acids with a volume ratio of 4:1, where potassium permanganate and hydrogen peroxide were selected as oxidizing agents. The temperature for GO preparation was changed over a range of 20–85 °C. The synthesized GO samples have been characterized by X-ray diffraction, scanning electron microscopy, electron dispersive spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible spectroscopy methods. It was shown that high quality GO can be synthesized at 20 °C but the purity of GO increased with the increase of the preparation temperature. The atomistic models of GO sheets prepared at different temperatures and according to the stoichiometric ratio of the functional groups found by XPS have been developed. Based on the developed models it was found that GO prepared at higher temperatures had more holes in the sheets supported with experimental images.

Effective photocatalytic methylene orange dye degradation ability in coloured textile contaminated water by highly efficient catalyst Schiff-based resin-encapsulated supported on TiO2@SiO2 metal oxide nanoparticles

ABSTRACT Present work reports the newly synthesized resin polymethylene, bis-2-methoxy-1-napthaldehy-o-phenylenediimine (PMBMNOPhen) and then react with titanium dioxide and silicon dioxide to form encapsulated resin by metal oxide nanoparticles (PMBMNOPhenTiO2/SiO2) and resulted in the material is polymethylene, bis-2-methoxy-1-napthaldehy-o-phenylenediimine titanium-dioxide nanoparticles (PMBMNOPhenTiO2). The resin-encapsulated metal oxide nanoparticles were successfully identified morphology, crystal structure, and light absorption capacity of samples were characterized via scanning electron microscope (SEM), X-ray diffraction, energy dispersive (EDS) X-ray diffraction analysis (XRD) and ultraviolet–visible spectroscopy methods. Afterwards, the resin-encapsulated metaloxide nanoparticles are used for degradation of methylene orange (MO) dye. The photo-oxidation rate of the dye is dependent on the different parameters: initial dye concentration, effect of time, the effect of NaBH4 and effect of dose of catalyst. The degradation of MO 60–80%% in real water samples with respect time of 30–60 minutes. These results confirm the prepared resin-encapsulated titanium dioxide nanoparticles (PMBMNOPhenTiO2/SiO2) displaying a great photocatalytic activity for the degradation of methylene orange dye under visible light irradiation effect of a catalyst in real water sample degradation. The synthesized catalyst (PMBMNOPhenTiO2/SiO2) was successfully applied in real dye water solution (colored water), collected from Jamshoro, Sindh (Pakistan). The resin-encapsulated metal oxide nanoparticles showed an excellent performance to reduce MO dye in contaminated water. These results approve that the resin-encapsulated titanium dioxide nanoparticles (PMBMNOPhenTiO2) display a great photocatalytic activity for the degradation of MO dye under visible light irradiation degradation. Photocatalytic degradation using resin-encapsulated (TiO2/SiO2) catalyst is effectively used for the textile dye (MO).

Investigation of 6-[5-(4-Methoxyphenyl) furan-2-yl] Nicotinonitrile as a New Corrosion Inhibitor for Carbon Steel in Acidic Solution: Chemical, Electrochemical and Quantum Chemical Studies

Theeffect of 6-[5-(4-methoxyphenyl) furan-2-yl] nicotinonitrile (MA-1160) as a new corrosion inhibitor for carbon steel (CS) in hydrochloric acid (HCl) solution was investigated using weight loss (WL), atomic absorption spectroscopy (AAS) and electrochemical measurements. The surface morphology of CS was tested using: scanning electron microscopy, atomic force microscope, attenuated total reflection–Fourier transform infra-red and ultraviolet–visible spectroscopy methods. The adsorption of MA-1160 on CS surface obeyed the model of Langmuir isotherm. Polarization data revealed that this inhibitor behave as mixed-type inhibitor. The spectroscopic measurements revealed the formation of a protective adsorbed layer on CS surface. Quantum chemical calculations were calculated and discussed using density functional theory method. The inhibition efficiency (% €) was 84% in WL, 86.4% in AAS, 86.0% in potentiodynamic polarization and 84.8% in EIS 86% at 21 µM. Thus, all the test methods gave good agreement with each other in % €.

Novel Drug Delivery System Based on Ginsenoside Rb1 Loaded to Chitosan/Alginate Nanocomposite Films.

Recently, drug delivery using natural and biodegradable nanoparticles has attracted huge attention. This study focused to deliver an anti-cancer and anti-inflammatory drug Ginsenoside Rb1 through chitosan-Alginate nanocomposite film prepared by solution method. Ginsenoside Rb1 is a dammaran saponin group, which is extracted from an herbaceous plant Panax notoginseng. Ginsenoside loaded alginate-chitosan nanocomposite films were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) methods. The FTIR spectra of alginate/chitosan/ginsenoside Rb1 nanocomposite films show that chitosan, alginate, and ginsenoside Rb1 are linked through the hydrogen bonding and dipolar-dipolar interactions. The FESEM image indicates that the chitosan and ginsenoside Rb1 dispersed well in the alginate matrix. The DSC diagrams display that melting temperature of alginate/chitosan/ginsenoside Rb1 nanocomposite films higher than that of chitosan and lower than that of alginate. It means that alginate and chitosan interact together. Investigation of the ginsenoside Rb1 release from alginate/chitosan/ginsenoside Rb1 nanocomposite films at different pH solutions and different ginsenoside Rb1 content has been carried out by ultraviolet-visible spectroscopy method. The rate of drug release is proportional to the increase in pH solution and inversely proportional to the content of loaded ginsenoside Rb1. The Rb1 release process includes two stages: burst release in the first 10 hours, then constant release afterwards. The suitable ratio of alginate/chitosan to prepare the alginate/chitosan/ginsenoside Rb1 nanocomposite films for further investigations was found out to be 8:2. Ginsenoside Rb1 release process from alginate/chitosan/ginsenoside Rb1 nanocomposite films was believed to be first-order kinetics in the first stage, and then the Rb1 release complies with Higuchi kinetic model in the slow release stage. This study demonstrated the novel synthesis methodology to design drug delivery system based on ginsenoside Rb1 loaded to chitosan/alginate nanocomposite films.

Spectroscopic Quantification of Surfactants in Solid Lipid Nanoparticles

Solid lipid nanoparticles (SLN) mainly consist of lipids and surfactants. However, the toxicity of surfactant cannot be ignored, as the surfactant may cause unexpected side effect. This study established model SLN with different surfactants, Tween 80 (T80) and poloxamer 188 (P188). It was aimed to establish ultraviolet-visible (UV-Vis) spectroscopy methods for quantifying the contents of T80 and P188 in the model SLN. The model SLN were produced by emulsification-precipitation method, and their particle size distribution was analyzed. The calibration curves for the contents of T80 and P188 were established. Surfactants in the model SLN were extracted by ultrasonication, and UV-Vis spectroscopy methods were utilized for quantification of surfactants in SLN. The deviation of precision and accuracy in P188 and T80 assay were acceptable, which indicated the method could be employed in sample quantification. Ten minutes was considered as the optimal ultrasonication time. And the contents of P188 and T80 were successfully measured by the established UV-Vis methods. The UV-Vis spectroscopy methods were developed for the quantification of T80 and P188 in the model SLN. It is expected that the methods could be extended to more SLN systems and applied for the quantification of other surfactants.

Tracing Sediment Sources Using Mid‐infrared Spectroscopy in Arvorezinha Catchment, Southern Brazil

AbstractThe widespread adoption of the sediment fingerprinting approach to guide catchment management has been limited by the cost and the difficulty to prepare and process samples for geochemical and radionuclide analyses. Spectral properties have recently been shown to provide a rapid and cost‐efficient alternative for this purpose. The current research objective was (i) to quantify the sediment source contributions in a 1∙19‐km2 rural catchment of Southern Brazil by using mid‐infrared (MIR) spectroscopy and (ii) to compare these results with those obtained with geochemical approach and near‐infrared and ultraviolet–visible spectroscopy methods. The sediment sources to discriminate were cropland surface (n = 20), unpaved roads (n = 10) and stream channel banks (n = 10). Twenty‐nine suspended sediment samples were collected at the catchment outlet during nine significant flood events. The sources could be distinguished by MIR spectroscopy. Cropland and channel bank sources mainly differed in their clay mineral contents, but their similar organic matter content complicated the MIR‐model predictions. Unpaved road contributions were discriminated from the other sources by their lower organic carbon content. When the results of the current research based on MIR spectroscopy are compared with those obtained using other sediment fingerprinting approaches, based on geochemistry and near‐infrared and ultraviolet–visible spectroscopy, an overestimation of channel banks contribution and an underestimation of cropland and unpaved road contributions is found. These results suggest that MIR spectroscopy can provide a useful tool that is non‐destructive, rapid and cheap for tracing sediment sources in rural catchments and for guiding the implementation of soil and water conservation measures. Copyright © 2016 John Wiley & Sons, Ltd.

Electrochemical Ultra-Low Detection of Isoniazid Using a Salicylaldamine Functionalised G1-DAB-(NH<sub>2</sub>)<sub>4</sub> Dendritic Sensor vs. UV-VIS Spectrophotometric Detection

A poly(propyleneimine) based dendrimer was synthesised and successfully functionalised with a copper centre within its branches. The dendrimer and corresponding metallodendrimer were successfully characterised using FTIR, HR-TEM and HR-SEM in order to determine the effect of the inclusion of copper into the dendritic structure. The incorporation of copper caused crystallinity as revealed in the HR-TEM and a sheet-like morphology as shown in the HR-SEM images. The resulting metallodendrimer was then applied as an electrocatalytic platform for the sensing of a first line TB drug called isoniazid. This method was compared to a routine laboratory detection using UV-Vis and was found to be much more sensitive to trace amounts of isoniazid in solution. The electrochemical detection was found to have a limit of detection (LOD) of 0.233 nM compared to 11.47 nM using the Ultraviolet-visible spectroscopy method.

Preparation of cobalt coated TiO2 and WO3–TiO2 nanotube films via photo-assisted deposition with enhanced photocatalytic activity under visible light illumination

Highly ordered TiO2 and WO3–TiO2 nanotubes were prepared by one-step electrochemical anodizing method and cobalt has been successfully deposited on these nanotubes by photo-assisted deposition process. The morphology, crystal structure, elemental composition and light absorption capability of samples were characterized by field emission scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectrometer and ultraviolet–visible spectroscopy methods. All cobalt loaded samples show an appearance of red shift relative to the unloaded samples. The degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of these novel visible-light-responsive photocatalysts. Results showed that the photocatalytic activity of bare WO3–TiO2 samples is higher than that with undoped TiO2 sample. Compared with unmodified TiO2 and WO3–TiO2, the Co/TiO2 and Co/WO3–TiO2 samples exhibited enhanced photocatalytic activity in the degradation of methylene blue. Kinetic research showed that the reaction rate constant of Co/WO3–TiO2 is approximately 2.26 times higher than the apparent reaction rate constant of bare WO3–TiO2. This work provides an insight into designing and synthesizing new TiO2–WO3 nanotubes-based hybrid materials for effective visible light-activated photocatalysis. The catalysts prepared in this study exhibit industrially relevant interests due to the low cost and high photocatalytic activity.

Cobalt modified tungsten–titania nanotube composite photoanodes for photoelectrochemical solar water splitting

Cobalt modified tungsten–titania nanotubes (Co/WTNs) with different amounts of cobalt were prepared by two methods; photo-assisted deposition and one-step electrochemical anodizing method. The morphology, crystallinity, elemental composition and light absorption capability of samples were characterized by field emission scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectrometer and ultraviolet–visible spectroscopy methods. All cobalt loaded samples show a red shift relative to the unloaded samples. The photo-catalytic water splitting was used as a model reaction to evaluate the photo-catalytic activity of the obtained samples. The photo-catalytic performance was examined under xenon lamp irradiation in 1 M NaOH electrolyte. All cobalt modified samples showed photo-catalytic properties better than that for the bare WTNs and bare TiO2 samples. The total amount of H2 evolved on the Co/WTNs2 sample was 1.9 times higher than that on the bare TiO2 sample. The catalysts prepared in this study exhibit industrially relevant interests due to the low cost and high photocatalytic activity. These new photoanodes are highly promising photoanodes for photo-catalytic hydrogen production.

In vitro cytotoxic activity of menispermaceae plants against HeLa cell line.

Background:Menispermaceae, a family of flowering plants, is a medium-sized family of 70 genera totaling 420 extant species, mostly of climbing plants. It has various medicinal properties, which are used in the Ayurvedic system of medicine. Plants belonging to this family are rich in alkaloids, especially bisbenzylisoquinoline type. The hypothesis of this study is that the bisbenzylisoquinoline alkaloids present in the selected plants may exhibit in vitro cytotoxic property.Aim:The present study is aimed at estimating the total alkaloidal content of methanolic extract of Cocculus hirsutus and Cissampelos pareira and evaluating the in vitro cytotoxic activity of both the extracts on the HeLa cell line.Settings and Design:Methanolic extracts of both the plants in the concentrations of 500, 250, 125, 62.5, and 31.25 μg/ml were assessed for its cytotoxic activity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Materials and Methods:Total alkaloidal content was studied for both the plants using ultraviolet-visible spectroscopy method. Methanol extracts of both the plants were tested for its inhibitory effect on HeLa cell line. Cytotoxicity of the plant extracts was evaluated by MTT assay. Nonlinear regression graph was plotted between % cell inhibition and Log10 concentration, and IC50 was determined using GraphPad Prism software.Results:Preliminary phytochemical studies confirm the presence of alkaloids in both the plants. The total alkaloids present in C. hirsutus and C. pareira were found to be 0.252%w/w and 0.1656%w/w respectively. The IC50 values of C. hirsutus and C. pareria were found to be 111 μg/ml and 129.3 μg/ml respectively.Conclusion:From this study, it is observed that C. hirsutus and C. pareira have in vitro cytotoxic activity against HeLa cell line.

Development of an acetylene black-dihexadecyl hydrogen phosphate composite-modified glassy-carbon electrode, and its application in the determination of lovastatin in dosage drug forms.

An electrochemical method has been established for the determination of lovastatin (LV). It is based on the enhanced oxidation of lovastatin at a novel acetylene black-dihexadecyl hydrogen phosphate composite-modified glassy-carbon electrode (AB-DHP/GCE) in the presence of Triton X-100. This electrode was prepared by dispersion of acetylene black particles in an aqueous suspension of DHP and the formation of a stable film of the resulting AB-DHP composite on the surface of a glassy carbon electrode (GCE). As a result of modification of the AB-DHP composite, the electrochemical response of lovastatin at GCE was apparently enhanced; this was apparent as amplification of the oxidation current and the negative shift of the oxidation potential. The oxidation current can be further increased in the presence of a trace amount of Triton X-100. The enhanced oxidation of lovastatin at AB-DHP/GCE was due to enlargement of the effective electrode area, catalysis of lovastatin oxidation by AB, and accumulation of lovastatin at the hydrophobic surface of the DHP layer, which would be enhanced by the coherence with Triton X-100. The effects of some working conditions on the oxidation current of lovastatin were tested and the calibration plot was examined. The result showed that the oxidation current was a linear function of lovastatin concentration in the range 2.5 x 10(-8) - 1.0 x 10(-6) mol L(-1) and a low detection limit of 4.0 x 10(-9) mol L(-1) was obtained under optimum conditions. This electrode system was applied to the determination of lovastatin in dosage drug forms and the results were in accordance with the ultraviolet-visible spectroscopy method.