UV-vis Spectrophotometry Techniques Research Articles

Synthesis of bioethanol from mixed vegetable wastes: Experimental methodology and characterization

AbstractBioethanol has been identified as a renewable product with high potential for application as biofuel. On the other hand, high volumes of agri‐food residues are generated daily. Such residues have potential as raw materials for industrial bioethanol production. There is a significant advance in the synthesis of biofuels from fruit and vegetable residues; however, most of the studies are focused on the conversion of a single type of raw material, limiting the application of the synthesis routes. This work presents a conversion methodology to produce bioethanol from carrot and broccoli residues and from their mixture; the samples of vegetable wastes has been collected in the municipality of Guanajuato, Mexico. Using the 1H NMR technique, the characteristic signals of bioethanol are identified. On the other hand, using the UV–VIS spectrophotometry technique, a maximum of 25.63 mg of total sugar content has been determined for the mixture. Likewise, a maximum bioethanol concentration of 60.6 g/L is obtained. From a refractometry and HPLC study, a conversion to bioethanol of 34.8% is determined for the mixture of residues. This work analyses the potential of broccoli and carrot residues for bioethanol production, either as isolated or as mixed wastes.

Antibacterial Efficacy of Susu Banana (Musa paradisiaca L.) Peel Methanol Extract and The Total Contents of Flavonoid and Phenolic Compounds

Banana peels contain antimicrobial properties. The objectives of this study are to determine the antibacterial efficacy of the methanol extract of susu banana peels and to quantify the total amount of phenolic and flavonoid components present. Maceration techniques were used for the extraction. The agar diffusion method was applied to determine antibacterial efficacy. The UV-Vis Spectrophotometry technique was performed to determine the amounts of phenolic and flavonoid. S. aureus and E. coli were severely inhibited by the methanol extract. With an increase in extract concentration, the antibacterial activity increased. The Minimum Bactericidal Concentration (MBC) was 4 and 15%, but the Minimum Inhibitory Concentration (MIC) was 3 and 10%, respectively. The methanol extract had a total of 1883,73 mg QE/100 g extracts of flavonoids and 273,09 mg GAE/100 g extracts of phenolics, respectively.

Determination of Total Phenolic Levels of Ethyl Acetate Fraction of Clove Leaves (Syzygium aromaticum (L) Merr)

Clove is a spice plant used in the kretek cigarette industry, food, beverage, and medicine. Clove leaves contain chemical compounds, namely saponins, flavonoids, tannins, and essential oils. The exploration of clove leaves has not been maximally carried out. Therefore, this study aims to determine the total phenolic content in the ethyl acetate fraction of clove leaves by using gallic acid as a comparison. Clove leaves were powdered and then macerated by ethanol. The ethanol extract was dissolved in distilled water and it was fractionated with ethyl acetate on a separating funnel. The method used in this assay is the UV-Vis spectrophotometry technique. The qualitative analysis was performed by adding the FeCl3 reagent. The results showed that the ethyl acetate fraction of clove leaves contained a total phenolic compound of 65.52 mg gallic acid equivalent per gram of extract (GAE/g). Thus, the ethyl acetate fraction of clove leaves is feasible to be developed as a source of phenolic compound.

Potential Application of Invasive Plant Species Datura innoxia for the Scopolamine Extracts of the Plant Organs and Analysis Using UV–VIS Spectrophotometry

Downy thorn-apple Datura innoxia (Solanaceae) is an invasive plant species which can be introduced either accidentally or deliberately and have the ability to acclimatize in new environmental conditions. Scopolamine is a natural alkaloid which occur in several Datura species, including Datura innoxia. Occurrence of alkaloid in all plant organs is crucially important from the viewpoint of medical use, but also as a risk of toxicity for humans and animals, this paper presents the influence of alcoholic solvents on the separation ability of tropane alkaloids using a conventional extraction method (Soxhlet extraction) in order to investigate the content of scopolamine from Datura innoxia dry biomass from Romania at the maturity stage. Two solvents were selected, investigated and compared, including ethanol (96%) and 1-butanol (99.6%). The results showed that 1-butanol was most suitable for the extraction of scopolamine from Datura innoxia areal parts (leaves, flowers, seeds, stem and root) then ethanol because of the high degree of lipophilicity of this alkaloid. The quantitative analysis was performed using UV–VIS spectrophotometry technique. The calibration curve for the analyte under the optimum conditions was obtained with a proper correlation coefficient of 0.9930. Scopolamine was identified in all vegetative organs with higher concentration in 1-butanol and the total content (µg g−1) was 186.87 in leaves, 150.89 in flowers, 63.27 in seeds, 42.50 in stem and 58.10 in root. These studies provide new insights into the potential use of invasive plant species Datura innoxia for extraction of the content of tropane alkaloids, especially scopolamine using different solvents regarding the toxicity and therapeutic potential of this plant alkaloid.

Enhanced photocatalytic activity of highly transparent superhydrophilic doped TiO2 thin films for improving the self-cleaning property of solar panel covers

Undoped and metal doped nanocrystalline TiO2 transparent thin films were synthesized on glass substrates via sol-gel/dip-coating method. TiO2 thin film coatings can be applied to the surfaces of solar panels to impart self-cleaning properties to them. The structural and optical properties of few nanometer-thick films were characterized by XRD, SEM, CA, AFM, XPS, and UV–Vis spectrophotometry techniques. The stoichiometric TiO2 films crystallized in anatase phase, with a particle size of ∼100 nm, which were uniformly distributed on the surface. The prepared films with a roughness of ∼1–5 nm, increased the hydrophilicity of the glass surface. Reducing the amount of Ti precursor (X) favored the improvement of film quality. To improve the photocatalytic activity of the TiO2 thin film, it was doped with Ni, Cd, Mo, Bi and Sr metal ions. The effect of metal doping on the photocatalytic activity of the films was investigated using the degradation process of methylene blue (MB) dye as the model contaminant. Among the prepared coatings, the Sr–TiO2 film showed the highest efficiency for MB degradation. It increased the dye degradation efficiency of the films under both UV and Vis lights. The kinetic investigations also showed that the degradation of MB by TiO2 and M − TiO2 films obeyed the pseudo-first order kinetics.

A Review on Analytical Method Development for the Estimation of a Potent Muscarinic Receptor Antagonist Tolterodine Tartrate

Background: A pharmaceutical will be clinically accepted if it is impurity-free and its dose is accurately maintained. For this, the contribution of analytical techniques for developing and validating a new pharmaceutical dosage form cannot be overlooked. Introduction: Tolterodine tartrate is a potent competitive muscarinic receptor antagonist. It binds to the muscarinic M3 receptors in the bladder selectively and competitively. It is used to treat urinary incontinence and overactive bladder syndrome. The 5-hydroxymethyl derivative is the pharmacologically active metabolite of Tolterodine tartrate, which is as potent as the main drug. It is available with α-adrenergic blocker Tamsulosin in combined pharmaceutical formulations, treating benign prostatic hyperplasia in men. This review article presents several analytical methods, including HPLC, HPTLC, UV-Visible spectrophotometry, spectrofluorimetry, electroanalytical, and various hyphenated techniques like GC-MS, LC-MS, LC-MS-MS, etc., for estimation of Tolterodine tartrate is present as a single material or in combined form in bulk materials, different pharmaceutical formulations, and biological matrices. Conclusion: HPLC and spectrophotometry are the most widely used methods for determining the drug in the bulk and pharmaceutical dosage form among all these methods. LC-MS and LC-MSMS are widely used for the estimation of Tolterodine tartrate from plasma and other biological fluids. All the methods included in this article are accurate, sensitive, and cost-effective.

CdSe ve CdSe/ZnO Filmlerin Elektrokimyasal Sentezi: Morfolojik, Yapısal ve Elektronik Özellikler

CdSe films were electrochemically prepared on ITO electrode in aqueous solution applying a constant potential. Structural, morphological and optical features of CdSe thin films were examined with FE-SEM, XRD and UV-visible spectrophotometry techniques. XRD results revealed CdSe films were deposited, in the form of cubic crystals from aqueous solution of Cd2+ and Se4+, in presence of Na2SO4 supporting electrolyte. Band gap values of CdSe films were found between 1.88 and 2.0 eV. Wide band gap ZnO was electrochemically deposited on narrow band gap CdSe to improve its optoelectronic properties. Band gap value of CdSe/ZnO nanonorods was determined as 2.7 eV. Mott-Schottky equation was utilized to calculate flat band potential (EFB), as well as charge carrier density (ND) of materials. ND values were found as 1.623×1020 and 9.186×1020 cm-3 for CdSe and CdSe/ZnO, respectively. ZnO offers higher stability and lower band gap is promising material to be utilized in solar cell applications.

Structural and Optical Properties of R6G Doped Nanotitania Thin Films Deposited via Sol–Gel Dip-coating Meth

Pure and rhodamine 6G (R6G) doped titanium dioxide (TiO2) nanostructure thin films with different concentrations (310-4 , 310-5 , 310-6 , and 310-7 ) M of doped TiO2 sol were deposited on glass substrate via dip-coated sol-gel method. Amorphous structure of the pure and doped TiO2 thin films was identified by X-ray diffraction (XRD) technique. UV-Visible (UV-vis) and fluorescence spectrophotometry techniques were used to study optical and spectroscopic characterization of the samples, respectively. The absorption spectra for all pure and doped TiO2 films indicate a strong absorbance in the UV region which open the possible application of these films for UV filter optical element. 50 nm blue shift of the absorption edge for the TiO2 films with respect to the sol was observed which proves the nanostructure texture of TiO2 thin films. Upon increasing dye concentration, a red shift in the maximum fluorescence emission peaks of R6G ethanolic solution and doped TiO2 sol was observed. The presence of R6G dye molecules in the matrix of TiO2 films is demonstrated by the appearance of two distinct intensity fluorescence peaks at 540 and 600 nm. Various fluorescence peaks of R6G doped TiO2 thin films were observed in UV-vis region under 300 nm pumping wavelength.

The influence of Cu2ZnSnS4 thin films with characteristics of treatment conditions on spray pyrolysis technique for solar cells applications

Generally, thin-film solar cells are used in CdTe or CIGS based on light-absorbing materials that it is non-toxic and cost. It is best on the materials for CZTS cost-effective, the high absorption coefficient of over 104 cm−1. CZTS based on electrical (light) conversion efficiency of 0.6% of the solar cell is an important growth in this research area was reached in the last five years. Cu2ZnSnS4 thin films have been prepared by spray pyrolysis technique for different substrate temperatures of 300 °C, 350 °C, 375 °C, 400 °C, and 450 °C with varying precursor concentrations. The prepared Cu2ZnSnS4 thin films for various temperatures were characterized for various parameters like its structure using X-ray diffraction (XRD), phase constituents with energy dispersive analysis (EDS), morphology by scanning electron microscope (SEM), and optical properties UV–vis spectrophotometry technique. The XRD and EDS results are embarked as a peak at a 2θ position of 28.5° corresponding to (112) planes. The excellent polycrystalline kieserite structure is obtained from XRD for the Cu2ZnSnS4 films. The organized harvests also exposed the morphology with size ranging from the formation of smooth, compact, and even surface of CZTS. The composition of the Cu2ZnSnS4 thin film fundamentally agrees with the theoretical value. The absorption coefficient in the order of 104 cm−1 is obtained. The experimental bandgap of 1.5 eV corresponds well with the substance Cu2ZnSnS4 materials analysis of SEM, and EDAX is making them excellent aspirants as absorbent materials for the thermal solar cell process.

Spray Pyrolysis Synthesized and ZnO–NiO Nanostructured Thin Films Analysis with Their Nanocomposites for Waveguiding Applications

In this work, we have prepared ZnO, NiO, and nanocomposites ZnO–NiO thin films elaborated by the chemical method of spray pyrolysis on glass substrates at a temperature of 480°C. The prepared samples have been analyzed by means of the X-ray diffraction (XRD), UV-visible spectrophotometry, micro-Raman and m-lines spectroscopies techniques. The structure of the thin ZnO films is hexagonal of the wurtzite type with a preferential orientation along the axis (002). The size of the crystallites, deduced from the XRD measurements, varies between 25 and 43 nm. The NiO films crystallize in the cubic structure with the size 4 nm of the crystallites. The micro-Raman study confirms the XRD results showing the presence of the vibrational modes characteristics of the wurtzite structure of ZnO and the cubic structure of NiO. The obtained films have an optical transmission varying from 60 to 95% in the visible region. The forbidden optical band energies, deduced from the transmittance, are 3.28 and 3.89 eV for the ZnO and NiO films, respectively. The optical waveguiding measurements carried out on pure ZnO and ZnO–NiO films show single-guided modes behavior (TE0 and TM0). These measurements have allowed deducing the thickness and the refractive index values which are respectively 250 nm and 1.89 for ZnO, 165 nm and 1.80 for ZnO–NiO thin films.

Effects of Zn doping concentration on the optical and photovoltaic properties of ZnxPb1−xS thin film-based solar cell prepared by chemical spray pyrolysis

The metal dopants in PbS thin films make a significant impact on its optical and electronic transport properties that make it useful for photovoltaic and other optoelectronic applications. The photovoltaic properties of Zn-doped nanostructured PbS thin films synthesized from zinc acetate, lead acetate, and thiourea as an absorber layer prepared using chemical spray pyrolysis were investigated. Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), and UV–visible spectrophotometry techniques were used to obtain stoichiometry, thickness, structural, and optical properties of the thin films before fabrication of Zn–PbS/CdS solar cell. The RBS revealed the stoichiometry ratio as ZnxPb1−xS and thickness range of 189.05–251.64 (1015 atoms/cm2). The inclusion of the Zn dopant drastically reduced the concentration of lead from the initial 40.93–14.95%. Optical analysis of the films gave high optical absorption and relatively low reflectance from visible toward the NIR region. An increase in energy bandgap was observed with Zn dopants inclusion from 0.53 to 1.65 eV, which fits the path of the solar radiation for maximum absorption. Photovoltaic properties revealed from the J–V measurement confirmed that Zn-doped sample 6% ZnAcet thin film solar cell gave a maximum short-circuit current density (Jsc) of 17.30 mA/cm2, open-circuit (Voc) 390 mV, fill factor (FF) 0.48, and conversion efficiency (η) of 2.7%.

Effect of heat treatment on structural, magnetic, elastic and optical properties of the co-precipitated Co0.4Sr0.6Fe2O4

The crystalline phase, elastic, magnetic, and optical properties of heated Co0.4Sr0.6Fe2O4 have been studied at different annealing temperatures. The samples have been scanned by (XRD), (HR-TEM), (FT-IR), (VSM), and UV–Visible spectrophotometry techniques. The cubic → hexagonal phase transition occurs at about 900 °C. During the precipitation process, the formed Sr(OH)2 exposed to atmospheric CO2 and the SrCO3 appeared as a second phase. So the precipitated powders are a mixture of cobalt ferrites and SrCO3, and the solid-state reaction between them leads to the transformation from cubic to hexagonal. Heating effects on the structural and magnetic parameters offer the possibility to modify the magnetic and electric phenomena to suit promising applications. The elastic moduli decrease by heating, whereas the average particle size increases in the range of 8–55 nm. The optical band-gap depends on the annealing temperature and was found to be ~2.78 eV, and the optical studies show a direct allowed transition in these nanostructures.

Transparent thin films of pure anatase Titania nanoparticles with low surface roughness prepared by electron beam deposition method

In this research, electron beam deposition method was used to synthesize Titanium dioxide (TiO2, Titania) thin films on quartz substrates at different oxygen partial pressures followed by thermal annealing. The samples were characterized by x-ray diffraction (XRD), UV-visible spectrophotometry, four-point probe and atomic force microscopy (AFM) techniques. A detailed study on the effects of deposition conditions on structural, optical, electrical and morphological properties of TiO2 films was systematically considered. The results reveal that all films possessed the anatase structure after heat treatment. The thermal annealing resulted in a gradual increase in crystallite size and optical transmittance while the corresponding refractive index decreased. The optical band gap, Eg, of TiO2 films increased from 3.76 eV to 3.83 eV. It is also found that electrical resistivity, ρ, decreased from 3.45 × 105 Ω cm to 1.25 × 104 Ω cm. Furthermore, the AFM micrographs revealed that the annealed film deposited at lower oxygen partial pressure produce a fine surface roughness suitable for many practical applications such as hydrophilic properties of thin films, for instance.

Gamma rays irradiation effects in thin film polyethylene terephthalate polymer

The effect of gamma rays irradiation on structural properties of polyethylene terephthalate (PET) has been studied using Fourier Transform Infrared Spectroscopy (FTIR), X-rays diffraction (XRD) and UV–Visible spectrophotometry techniques. The gamma rays irradiations were performed, using 60Co source with mean energy of 1.25 MeV, at Nuclear Research Centre of Algiers, Algeria. The gamma absorbed dose rate was about 1.3 kGy/h as measured using the Frick dosimeter. Several PET samples with a thickness of 6 μm were irradiated at room temperature with the presence of air atmosphere at different doses (0.05–5 MGy). The FTIR analysis reveals that the intensities of the different absorption bands decrease with increasing gamma rays dose. This is attributed to the chain scission induced by gamma rays irradiation. It is found from XRD analysis that the crystallinity is reduced after irradiation. The variation in crystallite size is also observed. The UV–vis spectra show a large absorption band extended from 310 to 355 nm assigned to the formation of extended systems of conjugate bonds with the creation of carbon clusters. The optical absorbance in this range increases linearly with the gamma rays dose. An empirical relation is established to estimate gamma dose from this correlation. Both direct and indirect energy gaps are found to decrease with increasing gamma rays dose indicating the appearance of new electronic transitions. Moreover, it is also observed that the Urbach energy increases with the gamma rays dose. This indicates the disorganization of the PET structure after irradiation.

Synthesis, Kinetics and a Full Mechanistic Investigation of Four-Component Reaction for Preparation of 2-Amino-3-Cyanopyridine Derivatives in the Presence of Green Catalysts

2-Amino-3-cyanopyridine derivatives have been synthesized via a four-component reaction of malononitrile (1), aromatic aldehyde (2), cyclohexanone (3), and amines (4) in the presence of fructose and maltose catalysts with good to excellent yields. In addition, for the first time we describe the experimental kinetics study and a full mechanistic investigation of title reaction. To determine the right position of each component in the reaction path, kinetic study of the reaction was carried out using UV–vis spectrophotometry technique. Based on temperature effects on the reaction rate, activation energy (Ea= 28.97 ± 0.21 kJ mol−1) and its parameters (ΔH‡ = 26.49 ± 0.23 kJ mol−1, ΔS‡ = −122.88 ± 0.67 J mol−1 K−1 and ΔG‡ = 63.12 ± 0.46 kJ mol−1) were determined, so the reaction was enthalpy and chemically controlled and also its mechanism was associative. By the change in the solvent polarity, it was found that polar solvents increase the reaction rate and the mixture of water/ethanol (50/50) was the best choice. Changing the structure of aniline (4) and benzaldehyde (2) by the substituent groups exhibited that the reaction proceeds faster in a poor electronic ring, regarding benzaldehyde (2), which is the result of the electron-withdrawing groups and a rich electronic ring for aniline, which is because of the electron donating groups. Further investigations on the partial orders of reactants approved the independency of the rate law to the concentrations of components (3) and (4), so the reaction was second-order kinetics corresponding to compounds (1) and (2) with the right rate law = . Step7 was recognized as the RDS.

Effect of excess oxygen content within different nano-oxide additives on the structural and optical properties of PVA/PEG blend

Different nano-oxides (Cr2O3, NiO, Co3O4) were added to polyvinyl alcohol/polyethylene glycol (70/30 wt%) blend. Rietveld profile analysis method was used to investigate the structure and microstructure characteristics of nano-oxide fillers. The effect of different nano-oxide fillers on the optical transparencies of the blend samples is confirmed. Co3O4 nano-oxide showed a higher uniform distribution within blends among other oxides. The variation of the absorption, the transmittance, the extinction coefficient, the refractive index and the energy gap (direct and indirect) of different blends based on different oxide fillers was examined by UV–Vis spectrophotometry technique. A single-term Sellmeier Oscillator approximation model was used to investigate the effect of excess oxygen atoms of the added nano-oxide fillers on the strength of the inter-band optical transitions, average excitation energy, average inter-band oscillator wavelength, the long-wavelength refractive index and the average oscillator strength. The effect of doping on the dielectric constant (real and imaginary) and optical conductivity of different blends behavior was investigated in detail as well.

Influence of different stabilizers on the morphology of gold nanoparticles

ObjectivesThe current study revealed that the used stabilizers greatly affect the morphology as well as the aspect ratio of the obtained gold nanoparticles.BackgroundControl of the morphology and dimensions of gold nanoparticles during the preparation is an important task for targeting certain applications in demand.Material and methodsGold nanoparticles were prepared by the reduction of tetrachloroauric(III) acid in the presence of different stabilizers: polyethyleneimine (PEI), polyvinylpyrrolidone (PVP), and chitosan.ResultsIn the case of using polyethyleneimine, the produced nanoparticles showed a homogenous spherical structure. Meanwhile, in the case of using polyvinylpyrrolidone and chitosan, the produced nanoparticles experience non-homogenous morphology with great diversity. Transmission electron microscopy (TEM) and UV-visible spectrophotometry (UV-vis) techniques were employed to study the criteria of the obtained gold nanoparticles.ConclusionsIt was obviously concluded that the type and concentration of the reducing agents that were added during gold preparation and acted as stabilizer templates affect to a great extent the morphology and particle shape. Also, stabilizers affect the homogeneity of the produced gold nanoparticles. In the case of using polyethyleneimine, the produced nanoparticles showed a homogenous spherical structure. Meanwhile, in the case of polyvinylpyrrolidone and chitosan, the produced nanoparticles experience non-homogenous morphology with great diversity.

Analytical Method for Determination of Thiocolchicoside in marketed Pharmaceutical Preparation: A Review

Thiocolchicoside a natural anti-inflammatory glycoside. It is the semi-synthetic derivative of the colchicine. It is a muscle relaxant with anti-inflammatory and analgesic effects. It works through selective binding to the GABA-A receptor. It prevents muscle contractions by activating the GABA inhibitory motor pathway. The article summarizes analytical method including the chromatographic method, LC-MS (Liquid Chromatography-mass spectroscopy), HPLC, GC-MS (Gas chromatography-mass spectroscopy), HPTLC and UV-Visible spectrophotometry techniques for estimation of Thiocolchicoside in biological samples, bulk and pharmaceutical formulation.

A review on analytical Method for Determination of Indapamide in Marketed pharmaceutical preparation

Indapamide is the Thiazide like diuretic drug used in treatment of Hypertension, as well as odema, Heart attack, stroke and heart failure in persons with high blood pressure. It is available in market single component and multicomponent formulations. The article summarizes 57 analytical method including the chromatographic method, LC-MS (Liquid Chromatography-mass spectroscopy), GC-MS (Gas chromatography-mass spectroscopy), spectriflurometric and UV Visible spectrophotometry techniques for estimation of Indapamide in biological samples, bulk and pharmaceutical formulation.

Cadmium removal by a low-cost magadiite-based material: Characterization and sorption applications

The sorption of cadmium from nitrate medium at room temperature was carried out using solid phase magadiite and magadiite impregnated with Cyanex 272 [bis(2,4,4-trimethylpentyl)phosphinic acid]. The sorbent materials have been characterized by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy-energy dispersive X-ray analyses (SEM-EDX) and thermogravimetric analysis (TGA/DTG). The UV–vis spectrophotometry technique was used to determine the amount of Cyanex-272 inserted into the solid support. Various parameters such as pH of the aqueous solution, initial Cd(II) concentration and equilibrium time were studied. The sorption data fitted the Sips sorption equation, and the sorption kinetics follows the model of the pseudo-second order. The maximum sorption capacity of Cd(II) was found to be 64.06 mg g−1 and 49.45 mg g−1 (i.e., 0.57 and 0.44 mmol g−1) from magadiite and magadiite-Cyanex 272, respectively. The elution of the materials was performed with 0.1 M HNO3 solution, and 80% of the initial sorbed cadmium was recovered.