Double Beam UV-VIS Spectrophotometer Research Articles

Investigation of structural, electrical and optical properties of nickel substituted CdSe thin films

The technologically important Cd1−xNixSe thin films with variable compositions (0 ≤ x ≤ 1) have been developed by a chemical deposition method. The structural, compositional, optical and electrical properties were studied by X-ray diffraction, Scanning electron microscopy, Atomic absorption spectroscopy, UV–visible double beam spectrophotometer and d.c. two probe method. XRD studies indicate polycrystalline in nature with hexagonal phase for all the samples. The lattice constants decrease with increase in nickel content in CdSe host lattice. The surface morphology study of all samples reveals uniform and spherical grains. An optical study of the samples shows that band gap value decreases with nickel content. Electrical measurements depict semiconducting properties of all samples.

Optical Characteristics of La-Doped ZnS Thin Films Prepared by Chemical Bath Deposition

Undoped and La-doped ZnS thin films are prepared by chemical bath deposition (CBD) process through the co-precipitation reaction of inorganic precursors zinc sulfate, thiosulfate ammonia and La2O3. Composition of the films is analyzed using an energy-dispersive x-ray spectroscopy (EDS). Absorption spectra and spectral transmittances of the films are measured using a double beam UV-VIS spectrophotometer (TU-1901). It is found that significant red shifts in absorption spectra and decrease in absorptivity are obtained with increasing lanthanum. Moreover, optical transmittance is increased as La is doped, with a transmittance of more than 80% for wavelength above 360 nm in La-doped ZnS thin films. Compared to pure ZnS, the band gap decreases and flat-band potential positively shifts to quasi-metal for the La-doped ZnS. These results indicate that La-doped ZnS thin films could be valuably adopted as transparent electrodes.

Spectrophotometric methods for the simultaneous estimation of ofloxacin and tinidazole in bulk and pharmaceutical dosage form

Aim: This work deals with the simultaneous estimation of Ofloxacin (OFL) and Tinidazole (TNZ) in in bulk and pharmaceutical dosage form, without prior separation, by three different techniques (Simultaneous equation, Absorbance ratio method and First order derivative method). Materials and Methods: The present work was carried out on Shimadzu electron UV1800 double beam UV-Visible spectrophotometer. The absorption spectra of reference and test solutions were carried out in 1 cm matched quartz cell over the range of 200 - 400 nm. Standard gift sample of OFL and TNZ obtain from Torrent pharmaceuticals Ltd., Baddi, Himachal Pradesh. Combined OFL and TNZ tablets were purchased from local market. Methanol from Merck Ltd and distilled water are used as solvent. Results: The first method is the application of simultaneous equation. Where the linearity ranges for OFL and TNZ were 5-30 μg/ml and 10-50 μg/ml respectively. The second method is the determination of ratio of absorbance at 278nm, the maximum absorption of TNZ and isobestic wavelength 283 nm, the linearity ranges for OFL and TNZ were 5-30 μg/ml and 10-50μg/ml respectively. The third method is the first order derivative method, where the linearity ranges for OFL and TNZ were 5-30 μg/ml and 10-50 μg/ml respectively. The results of the analysis have been validated statistically and by recovery studies, where the percentage recovery was found to be 100.9±0.49 and 97.30±0.20 using the simultaneous equation method, 98±0.45 and 100.4±0.48 using the graphical absorbance ratio method and 99.10±0.40 and 84.70±0.70 using first derivative method, for OFL and TNZ respectively. Conclusions: The proposed procedures are rapid, simple, require no preliminary separation steps and can be used for routine analysis of both drugs in quality control laboratories.

UV–visible and infrared absorption spectra of gamma irradiated V 2O 5-doped in sodium phosphate, lead phosphate, zinc phosphate glasses: A comparative study

Radiation-induced defects generated by successive gamma irradiation have been investigated in V 2O 5-doped phosphate glasses of three basic compositions, namely, sodium metaphosphate, lead metaphosphate and zinc metaphosphate. Glasses were prepared from chemically pure materials. Melting was carried at 900°–1100 °C for 1 h and with several stirrings of the melt to achieve homogeneity. The glassy samples were annealed at 200°–250 °C and left to cool to room temperature at a rate of 20 °C/h. Polished samples from undoped and V-doped samples of equal thickness. ~ 2 mm were measured in a double beam UV–visible spectrophotometer at 200–1000 nm before and after gamma irradiation. Induced defects were analyzed for these three phosphate glass systems. Infrared absorption spectra were measured for the prepared undoped and V-doped samples by the KBr technique before irradiation and after being subjected to a high dose of 7 M Rads (7 × 10 4 Gy). The cumulative effects of gamma irradiation on the UV–visible spectra are correlated with the intrinsic and extrinsic defects within the various three glasses. Some shielding behavior for the various glasses towards successive gamma irradiation are observed and realized in relation to the different partner anions studied. The effect of gamma irradiation on IR spectra indicates the persistence of the main characteristic bands due to phosphate network and the minor changes are correlated with the possible changes in the bond lengths and/or bond angles of the building units during the irradiation process. The effect of V 2O 5 on the IR spectra is correlated with the depolymerization effect of the glass network.

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.

Synthesis and Optical Properties of ZnO-TeO2 Glass System

Problem statement: Systematic series of ZnO-TeO 2 glasses with mole fraction of 0.10-0.40 ZnO content with an interval of 0.05 were studied t o obtain their physical and optical properties. Approach: All the glass samples were synthesized by rapid me lting quenching method under controlled conditions, while their refractive indic es (n) were measured by the EL X-02C high precision ellipsometer. The room temperature absorption of al l glass samples were determined using Camspec M350 double beam UV-visible spectrophotometer. The infrared (IR) spectra of each glass samples were recorded with Thermo Nicolet Fourier Transform-Infrared (FT-IR) spectrophotometer. Their physical properties were measured and the amorphous nature was confirmed by the x-ray diffraction technique. Results: The increase of refractive index of the TeO 2-ZnO glasses with the addition of ZnO was best explained in terms of either electron dens ity or polarizability of the ions. The absorption e dge shift to higher energy (shorter wavelength) with in creasing ZnO content was observed in this glass. The optical band gap (E opt ) of zinc tellurite glass decreases with increasing of ZnO content probably due to the increment of Non-Bridging Oxygen (NBO) ion contents which eventually shifted the band edge to lower energies. Conclusion/Recommendation: The physical and optical properties of zinc tellurite glasses were found generally affected by the changes in the glass composition. FTIR spectra of zinc tellurite glass revealed broad, weak and stron g absorption bands in the investigated range of wav e numbers from 4000-400 cm -1 which associated with their corresponding bond modes of vibration and the glass structure. The addition of ZnO into Te O 2 glass network shifted the major band from 626 cm -1 (for pure TeO 2 glass) to the band at around 669 cm -1 .

Catalytic spectrophotometric determination of iodine in coal by pyrohydrolysis decomposition

A method for the determination of iodine in coal using pyrohydrolysis for sample decomposition was proposed. A pyrohydrolysis apparatus system was constructed, and the procedure was designed to burn and hydrolyse coal steadily and completely. The parameters of pyrohydrolysis were optimized through the orthogonal experimental design. Iodine in the absorption solution was evaluated by the catalytic spectrophotometric method, and the absorbance at 420 nm was measured by a double-beam UV-visible spectrophotometer. The limit of detection and quantification of the proposed method were 0.09 μg g −1 and 0.29 μg g −1, respectively. After analysing some Chinese soil reference materials (SRMs), a reasonable agreement was found between the measured values and the certified values. The accuracy of this approach was confirmed by the analysis of eight coals spiked with SRMs with an indexed recovery from 94.97 to 109.56%, whose mean value was 102.58%. Six repeated tests were conducted for eight coal samples, including high sulfur coal and high fluorine coal. A good repeatability was obtained with a relative standard deviation value from 2.88 to 9.52%, averaging 5.87%. With such benefits as simplicity, precision, accuracy and economy, this approach can meet the requirements of the limits of detection and quantification for analysing iodine in coal, and hence it is highly suitable for routine analysis.

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.