Double Beam UV-VIS Research Articles

Development and Validation of Analytical Method for Standardisation of Curcumin Using RP-HPLC Method in Prepared Extract

Objective: The main objective of present work is to develop and validate simple, precise and accurate analytical method for identification of curcumin using RP-HPLC method in prepared extract. Methods: Spectrophotometric determination was performed on a Perkin-Elmer UV-VIS Double Beam Spectrophotometer to know the maximum absorbance of the compounds. Chromatographic separation was achieved using merck C18 analytical column (5 µm, 250 mm x 4.6 mm, i.d). The optimized solvent system consisted of methanol, acetonitrile in the ratio of 30:70 v/v. The effluents were detected by means of UV detector at 415nm. The proposed method was validated in accordance with International Conference on Harmonisation (ICH) guidelines. Results: Linearity was observed at a concentration range of 2.5-15µg/ml with a regression equation of y = 77703x – 586.13 and correlation coefficient of 0.9993. The retention time was found to be at 1.72min by means of the proposed method. The method was validated according to ICH guidelines and was found to contain the %RSD values below 2% which shows that the method was precise, accurate and specific. Conclusion: The developed method was validated as per the ICH guidelines which show that the method is sensitive, simple, precise and accurate. Thus the method is applied for the identification of curcumin in prepared extracts.

DEVELOPMENT AND VALIDATION OF UV-SPECTROPHOTOMETRIC METHOD FOR ESTIMATION OF HYDROQUINONE IN BULK, MARKETED CREAM AND PREAPARED NLC FORMULATION

Objective: The aim of the present work was to develop a simple, rapid, accurate and economical UV-visible spectrophotometric method for the determination of hydroquinone (HQ) in its pure form, marketed formulation as well as in the prepared nanostructured lipid carrier (NLC) systems and to validate the developed method.Methods: HQ was estimated at UV maxima of 289.6 nm in pH 5.5 phosphate buffer using UV-Visible double beam spectrophotometer. Following the guidelines of the International Conference on Harmonization (ICH), the method was validated for various analytical parameters like linearity, precision, and accuracy robustness, ruggedness, limit of detection, quantification limit, and formulation analysis.Results: The obtained results of the analysis were validated statistically. Recovery studies were performed to confirm the accuracy of the proposed method. In the developed method, linearity over the concentration range of 5-40 μg/ml of HQ was observed with the correlation coefficient of 0.998 and found in good agreement with Beer Lambert’s law. The precision (intra-day and inter-day) of the method was found within official RCD limits (RSD<2%).Conclusion: The sensitivity of the method was assessed by determining the limit of detection and limit of quantification. It could be concluded from the results obtained that the purposed method for estimation of HQ in pure form, in the marketed ointment and in the prepared NLC-formulation was simple, rapid, accurate, precise and economical. It can be used successfully in the quality control of pharmaceutical formulations and for the routine laboratory analysis.

Comparison the optical properties for Bi2O3 and NiO ultrathin films deposited on different substrates by DC sputtering technique for transparent electronics

Bismuth and Nickel transparent oxides thin films were grown on glass and flexible polyethylene terephalate (PET) substrates by DC sputtering technique at room temperature 300 K. The structures of Bi2O3 and NiO films were analyzed by X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM). A profilometry is used to measure the thicknesses of the ultrathin films. These values were established by a spectro-ellipsometry technique with a new amorphous dispersion model in the range of 200 nm–2200 nm with one nm increment. In addition, the optical constants of these films were investigated using a double beam UV–Vis–NIR spectrometer and a spectro-ellipsometry and compared using the same wavelength range. They present an excellent agreement. According to the optical transmittance spectra of the films a high average transmittance in the visible region of each sample deposited onto different substrates is measured. Moreover, the absorption coefficients and the optical energy gaps for four types of optical transitions (allowed direct, forbidden direct, allowed indirect, forbidden indirect) of the films were determined and compared with the two different techniques. Finally, the nature of the structure and morphology of Bi2O3 and NiO ultrathin films has been analyzed and compared.

Structure, Morphology and Opto-Electrical Properties of Nanostructured Indium Doped SnO2 Thin Films Deposited by Thermal Evaporation

Indium doped Tin oxide (SnO2: In) thin films of various thicknesses (200-600 nm) with fixed 2% indium (In) concentration were prepared by thermal evaporation method onto glass substrates under high vacuum (10-6 Torr). As deposited films were vacuum annealed at 200o C for 60 minutes. The structure, optical, electrical and morphology properties of SnO2: In thin films were investigated as a function of film thickness. The XRD analysis revealed that films were polycrystalline in nature with a tetragonal structure having (110) plane as the preferred orientation. The average crystalline size increased from 34.8 to 51.25 nm with increase of film thicknesses. The surface morphology of the doped films was obtained by Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM). Optical transmittance was obtained from a double beam UV-Vis- NIR spectrophotometer. Maximum transmittance varied from 65-76% in the visible range of the spectrum. Optical band gap (Eg) varied between 2.89 and 3.20 eV. The resistivity of SnO2: In thin films was as high as 105 Ω-cm. Activation energy of the films were found to be 0.18 to 0.47 eV for 300-600 nm film thicknesses. Due to high optical band gap and high electrical resistivity, these nanostructured films can be used in optoelectronic devices especially as opto-insulator.

The substrate effect on Ge doped GaN thin films coated by thermionic vacuum arc

This study focuses on characterization and understanding of the substrate effect on Ge doped GaN thin films coated onto transparent substrates. The produced films were deposited onto unheated glass and unheated polyethylene terephthalate by using thermionic vacuum arc technique. Gallium nitride and germanium pellets were used in the thin film production. Reflectance, refractive index and thicknesses of Ge doped GaN thin films were measured by optical interferometer using Cauchy model for fitting. The transmittances were determined in the wavelength range between 200 and 1000 nm by using UV–Vis double beam spectrophotometer. The optical Tauc method was used to determine the band gap energies of produced thin films. Surface morphologies of produced thin films were characterized by atomic force microscopy and also field emission scanning electron microscopy. In conclusion, the substrate effect on the optical and morphological properties of the produced thin films was observed.

Structural and optical behaviour of cerium doped TiO2 thin films prepared by spray pyrolysis method

The Cerium doped titanium oxide (CexTi1−xO2 with x = 0 and 0.1) thin films were deposited on the glass substrate with the substrate temperature of 400 °C using Spray pyrolysis technique. The phase confirmation of the grown thin films was confirmed by X-ray diffraction analysis. From the XRD analysis, the sample shows the amorphous structure. Their surface morphology was probed using Scanning Electron Microscopy and the quality of the grown films was identified by atomic force microscopy analyses. The functional group and optical studies of the prepared films were characterised by Fourier Transform Infra-Red spectroscopy and UV–Vis-double beam spectrometer. The optical energy gap was determined by transmittance measurement.

Synthesis and Characterization of Uniform Spherical Nanoporous TiO2Aerogel Templated by Cellulose Alcohol-Gel with Enhanced Photocatalytic Activity

The spherical nanoporous TiO2aerogels were prepared by a simple ethanol-thermal method, using spherical cellulose alcohol-gel as the template. The morphology, crystalline structure, pore size, specific surface area, and the photocatalytic activity of obtained TiO2aerogel were separately characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2adsorption-desorption isotherms, and double beam UV-VIS spectrophotometer. The characteristics of TiO2aerogels presented uniform sphere shape, good internal structural morphology, high specific surface area (ranging from 111.88 to 149.95 m2/g), and good crystalline anatase phase. Moreover, methyl orange dye was used as the target pollutant to characterize the photocatalytic activities and the adsorption performance. The photocatalytic experiment shows that the obtained spherical TiO2aerogels had a higher degradation ratio of 92.9% on methyl orange dye compared with aspherical TiO2aerogels prepared from other concentrations of tetrabutyl orthotitanate (TBOT).

Enhanced photocatalytic activity of supported CuO–ZnO semiconductors towards the photodegradation of mefenamic acid aqueous solution as a semi real sample

The elimination mefenamic acid (MA) as a pollutant from the aquatic environment using Hg lamp during a catalytic photodegradation process using supported ZnO–CuO onto clinoptilolite nanoparticles (NCP) was the aim of the study. Raw and supported clinoptilolite were characterized by FT-IR, XRD, DRS, TEM and SEM techniques. The changes of MA concentration determined by UV–vis double beam spectrophotometer at λmax 285nm and used for the calculation of its degradation extent. Better degradation efficiencies obtained for the supported the hybridized ZnO–CuO system onto NCP with respect to unsupported one and supported/unsupported ZnO and CuO. The degradation efficiencies are dependent to the experimental conditions and hence the parameters were optimized to reach the highest efficiencies.

Deposition of a Mo doped GaN thin film on glass substrate by thermionic vacuum arc (TVA)

Current research presents a new deposition method for GaN thin films that produces in a very short production time for GaN-based solid-state applications. A Mo doped GaN thin film on a glass substrate was produced by thermionic vacuum arc (TVA) technique. The TVA technique is a novel non-reactive plasma technique. The optical properties were determined by Filmetrics F20 interferometer and UV–Vis double beam spectrophotometer. The surface morphology was analyzed using field emission scanning electron microscopy and atomic force microscopy. The mean thickness value was measured as 100 nm by Filmetrics interferometer. The crystalline structure of the produced thin film has a Wurtzite crystal structure (004) as obtained by X-ray diffraction. Hardness value was determined as 14 GPa with the Oliver–Pharr method. The obtained properties are consistent with the values reported in related literature. The findings indicate that the TVA method provides advantages for optical and industrial applications.

Studies on Photo Degradation of Indigo Carmine Dye by Mechanochemically Synthesized Nano Zinc Selenite

In the present paper a novel mechanochemical synthesis method was introduced for the synthesis of zinc selenite. The product was obtained at 320 °C by mechanochemical method for a period of 20 h. The structural and micro structural properties of ZnSeO3 material was characterized by various analytical techniques like FT-IR, UV-DRS, XRD and SEM. The aim of the present work is to see the application of nanocrystalline material ZnSeO3 for photodegradation of indigo carmine dye with respect to various dye concentrations and amount of catalyst. The XRD analysis confirms orthorhombic structure of ZnSeO3 and the average particle size was found to be below 10 nm. Futher, the effect of pH and dye concentration on photodegradation was studied. The photodegradation reaction was monitored on the UV-visible double beam spectrophotometer. ZnSeO3 treatment exhibited 93% degradation of indigo carmine dye.

Spectrophotometric method development and validation of itopride hydrochloride in bulk and dosage form.

A simple, precise and economical spectrophotometric method for the estimation of Itopride hydrochloride in pharmaceutical bulk and tablet dosage form was developed and validated. Identification was carried out using a UV-visible double beam spectrophotometer detector with working wavelength at 258nm in 0.1N HCl medium. The method was validated with respect to its specificity, linearity range, accuracy, and precision in analytical media. Itopride hydrochloride show the maximum absorbance (λmax) at 258 nm, Regression analysis showed good correlation in the concentration range 5-100 mcg/ml and 96.80 to 106.84% recovery with relative standard deviation 0.293 to 3.98%. Statistical treatment of data reflects that the proposed method is precise, accurate and easily applicable for determination of Itopride hydrochloride in bulk and pharmaceutical preparation. Keywords: Spectrophotometric; Itopride hydrochloride; Validation.

Central lumpectomy with resection of the nipple-areolar complex for retroareolar or central breast cancers

Bismuth and Nickel transparent oxides thin films were grown on glass and flexible polyethylene terephalate (PET) substrates by DC sputtering technique at room temperature 300 K. The structures of Bi2O3 and NiO films were analyzed by X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM). A profilometry is used to measure the thicknesses of the ultrathin films. These values were established by a spectro-ellipsometry technique with a new amorphous dispersion model in the range of 200 nm–2200 nm with one nm increment. In addition, the optical constants of these films were investigated using a double beam UV–Vis–NIR spectrometer and a spectro-ellipsometry and compared using the same wavelength range. They present an excellent agreement. According to the optical transmittance spectra of the films a high average transmittance in the visible region of each sample deposited onto different substrates is measured. Moreover, the absorption coefficients and the optical energy gaps for four types of optical transitions (allowed direct, forbidden direct, allowed indirect, forbidden indirect) of the films were determined and compared with the two different techniques. Finally, the nature of the structure and morphology of Bi2O3 and NiO ultrathin films has been analyzed and compared.

Quantitative and qualitative studies of silica in different rice samples grown in north of Iran using UV–vis, XRD and IR spectroscopy techniques

Silicon is an essential trace element and is found in vegetables, fruits, cereals, water, pasta and rice ( Oryza sativa). In this work, the silica content of different types of rice grains were measured. Here, we used the heteropoly blue photometric method with a double beam UV–vis spectrophotometer to determine the amount of silicon in rice samples ( n = 7) that were collected in the north of Iran. The samples were digested with wet-ashing method by microwave-assisted heating and then treated with ammonium molybdate to produce a yellow color compound in acidic solution (ca. pH 1.2) and then reduced to give a heteropoly compound with a blue color. Analyses were performed using standard addition method and absorbance values were measured with double beam UV–vis spectrophotometer at λ max = 815 nm. Results indicated that the silica content was 307–451 mg/kg for the samples. X-ray diffraction patterns and infra-red spectra were obtained from rice samples without any sample treatment.

Characterization of the Bifunctional γ-Glutamate-cysteine Ligase/Glutathione Synthetase (GshF) of Pasteurella multocida

Glutamate-cysteine ligase (gamma-ECL) and glutathione synthetase (GS) are the two unrelated ligases that constitute the glutathione biosynthesis pathway in most eukaryotes, purple bacteria, and cyanobacteria. gamma-ECL is a member of the glutamine synthetase family, whereas GS enzymes group together with highly diverse carboxyl-to-amine/thiol ligases, all characterized by the so-called two-domain ATP-grasp fold. This generalized scheme toward the formation of glutathione, however, is incomplete, as functional steady-state levels of intracellular glutathione may also accumulate solely by import, as has been reported for the Pasteurellaceae member Haemophilus influenzae, as well as for certain Gram-positive enterococci and streptococci, or by the action of a bifunctional fusion protein (termed GshF), as has been reported recently for the Gram-positive firmicutes Streptococcus agalactiae and Listeria monocytogenes. Here, we show that yet another member of the Pasteurellaceae family, Pasteurella multocida, acquires glutathione both by import and GshF-driven biosynthesis. Domain architecture analysis shows that this P. multocida GshF bifunctional ligase contains an N-terminal gamma-proteobacterial gamma-ECL-like domain followed by a typical ATP-grasp domain, which most closely resembles that of cyanophycin synthetases, although it has no significant homology with known GS ligases. Recombinant P. multocida GshF overexpresses as an approximately 85-kDa protein, which, on the basis of gel-sizing chromatography, forms dimers in solution. The gamma-ECL activity of GshF is regulated by an allosteric type of glutathione feedback inhibition (K(i) = 13.6 mM). Furthermore, steady-state kinetics, on the basis of which we present a novel variant of half-of-the-sites reactivity, indicate intimate domain-domain interactions, which may explain the bifunctionality of GshF proteins.

Dissolution and assaying of multicomponent tablets by chemometric methods using computer-aided spectrophotometer

Dissolution of three component tablets containing paracetamol (APAP), propyphenazone (PP), and caffeine (CAF) was carried out by USP paddle method. Three chemometric methods; inverse least square (ILS), principal component regression (PCR) and partial least squares (PLS) were applied to simultaneous assay of APAP, PP and CAF in tablets. The PCR, PLS and ILS methods were applied to simultaneous dissolution APAP, PP and CAF in tablets using a double beam UV–Vis spectrophotometer without any chemical separation and any graphical treatment of the overlapping spectra of three drugs. Twentytwo mixture solutions in different concentrations were prepared in simulated gastric juice (SGJ, USP) for the chemometric calibrations as training set. The absorbance data matrix was obtained by measuring the absorbance at 14 wavelength points (from 222.5 to 292.5 nm) with the intervals of 5 nm (Δ λ=5 nm) in the spectral region between 200 and 310 nm. Training set and absorbance data were used for the calibrations of chemometric methods. The developed calibrations were tested for the previously prepared solutions of mixture of three drugs for the validation of the assay method. The chemometric calculations were performed by using the ‘ maple v’ software. The results of three chemometric methods were statistically compared with each other. These chemometric calibrations were successfully applied to the content uniformity and dissolution of the multicomponent tablets without any separation procedure. The synthetic mixtures of three drugs were used for the validity of the calibrations. Means recoveries (percent) and relative standard deviation of PLS, PCR and ILS methods were found to be 100.1±0.6, 101.4±1.6 and 100.1±0.6 for APAP; 100.9±3.2, 102.0±3.3 and 100.9±3.2 for PP; 99.9±3.5, 101.6±3.3 and 99.9±3.2 for CAF, respectively. Dissolution profiles of three component tablets were performed. More than 95% of drugs were dissolved within 15 min. All of the three-chemometric methods in this study can be satisfactorily used for the quantitative analysis and for dissolutions test of multicomponent dosage form.