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Search Results: 1 - 10 of 5579 matches for " UV- Spectroscopy "
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International Journal of Pharmacy and Biological Sciences , 2011,
Abstract: Simple precise accurate UV Spectroscopic method has been developed and validated for estimation of valsartan in pure and pharmaceutical dosage form. UV Spectroscopic method which is based on measurement of absorption of UV light, the spectra of valsartan in methanol showed maximum wave length at 250nm and calibration graphs were plotted over the concentrations ranging from 2-20μg/ml of valsartan with correlation coefficient 0.9968 validation was performed as per ICH Q2 (R1) guidelines for linearity, accuracy, precision and recovery. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.15 and 0.449 respectively by simple UV Spectroscopy .The proposed method was validated.
Studies on the Effect of the Capping Materials on the Spherical Gold Nanoparticles Catalytic Activity  [PDF]
Roshdi Seoudi, Doaa A. Said
World Journal of Nano Science and Engineering (WJNSE) , 2011, DOI: 10.4236/wjnse.2011.12008
Abstract: Size-controlled gold nanoparticles (AuNPs) were prepared in the presence of different capping materials (sodium citrate, cetyltrimethylammonium bromide (CTAB), and chitosan). The results obtained suggest that the AuNPs were synthesized with different particle size, which is controlled by changing the molar ratio between sodium citrate, (CTAB), and chitosan to Au (III). The catalytic activities of the AuNPs with different capping materials were studied for 4-nitrophenol reduction by NaBH4 as a model reaction. AuNPs with different capping materials is comparable from the value of the apparent rate constant of 4-nitrophenol reduction (0.6 × 10–3, 1.9 × 10–3, and 2.4 × 10–3 s–1) for sodium citrate, CTAB and chitosan. From the results, it is concluded that, AuNPs catalyzed the electron transfer process between and nitro compounds with all the capping materials used AuNPs capped by chitosan were more active for the reduction than the other two.
Synthesis and Humidity Sensing Investigations of Nanostructured ZnSnO3  [PDF]
Rama Singh, Avadhesh Kumar Yadav, Chandkiram Gautam
Journal of Sensor Technology (JST) , 2011, DOI: 10.4236/jst.2011.14016
Abstract: In this paper zinc stannate (ZnSnO3) nanoparticles was synthesized by a chemical precipitation method. The synthesized samples were characterized using X-ray powder diffraction (XRD), Differential scanning calorimetry (DSC) and UV-Visible absorption spectroscopy. Sensing material was made as pellet by hydraulic press machine under uniform pressure of 616 MPa. Then the material was annealed at 600C. Surface morphologies of the samples were analyzed using Scanning electron microscopy (SEM) for pellet of different weight ratio annealed at 600C. The XRD pattern indicates that ZnSnO3 has a perovskite phase with an orthorhombic structure having minimum crystallite size 4 nm. Further, humidity sensing investigations of these sensing materials were done. Our result indicate that ZnSnO3 in form of pellet annealed at 600C for 1:4 weight ratio was most sensitive of humidity in comparison to pure SnO2 under same conditions. Maximum sensitivity of the sample was 3 GΩ/% RH which is better in comparison to pure SnO2. The results were reproducible up to ± 77% after 2 months of observations.
Technical Note: Synthesis and Characterization of Anisotropic Gold Nanoparticles  [PDF]
Tamsyn Grewar, Mariekie Gericke
Advances in Nanoparticles (ANP) , 2012, DOI: 10.4236/anp.2012.13003
Abstract: Anisotropic gold nanoparticles were synthesized in a simple, environmentally benign process under ambient conditions of temperature and atmospheric pressure using bovine serum albumin (BSA) as both the reductant and biotemplate. Two types of anisotropic nanoparticles were produced in the system, namely larger two dimensional plates and smaller three-dimensional nanoparticles. Since the characteristics of nanoparticles are largely determined by their morphology, a simple centrifugation step was included to roughly separate the larger plate-like particles from the smaller more compact particles. In an attempt to identify potential applications, the properties of the particles were determined by TEM, SEM, STEM-EDS, UV-Vis spectroscopy and photoluminescence. The results of this study identified several optical properties of gold nanoparticles.
Study of Effects of Low Doses UV Radiation on Microporous Polysulfone Membranes in Sterilization Process  [PDF]
Ni Nyoman Rupiasih, Hery Suyanto, Made Sumadiyasa, Nyoman Wendri
Open Journal of Organic Polymer Materials (OJOPM) , 2013, DOI: 10.4236/ojopm.2013.31003

Synthetic membranes have gained an important place in chemical technology and are used in a broad range of applications. UV irradiation is an age old process used for disinfection as well as for sterilization purposes. It is used for sterilizing equipment in which polysulfone (PSf) membranes are used. As a result, short time UV irradiation of polymer membranes has acquired importance in recent times. In the present study, microporous polysulfone membranes with0.108 mmthickness have been prepared using phase inversion method. Effect of UV irradiation on the membranes for short time intervals (0 - 60 minutes) has been investigated using UV-Vis and FTIR spectrophotometer, and SEM. The performance of the membranes has studied by filtration techniques. UV-Vis and IR spectra analysis and SEM images obtained suggest that chains scission and crosslink have occurred simultaneously in the irradiated membranes by UV radiation in a dose dependant manner. The pure water flux (PWF) values of irradiated membranes obtained from filtration studies were higher compared to that of the control membrane. These results show that a very short UV irradiation (2 minutes) affected the physicochemical characteristics of microporous polysulfone membrane which it increases with increase in time.

In Deep UV Quantitative Analysis of Multi-Element Low Alloy Steel by Laser-Induced Breakdown Spectroscopy  [PDF]
Yong Xin, Lanxiang Sun, Zhibo Cong, Lifeng Qi, Yang Li, Zhijia Yang
Journal of Computer and Communications (JCC) , 2013, DOI: 10.4236/jcc.2013.17005
Abstract: The multi-element components of low alloy steel were quantified by using laser-induced breakdown spectroscopy (LIBS) in deep UV. The Nd:YAG pulsed laser was used to produce plasma. The spectrum was simultaneously obtained by deep UV spectrometer. This paper studied the influence of experiment parameters on LIBS spectral intensity, such as delay, energy of laser, and the distance between the focusing lens and the surface of the sample. With the optimal expe- riment parameters, the characteristic lines of C, Ni, Si, Cr and Cu contained in low alloy steel were selected for quantit- ative analysis and the calibration curves of these elements were obtained. The linear correlation coefficient was good. Using the calibration curves to quantitative analysis for the sample 05-d, and the relative error of analytical results is less than 10% for most elements.
Novel Nondestructive Measurement of Dye Adsorption on Solid Titania Films for Its Sensitized Solar Cells  [PDF]
Fahd M. Rajab
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2014, DOI: 10.4236/jmmce.2014.23021
Abstract: A new nondestructive quantitative method is developed to measure the adsorption of dyes in solid titania films for dye-sensitized solar cells. UV-vis spectroscopy study showed that the absorbance of dye in the solid film can be directly related to the absorbance measured by the typical destructive method used to quantify concentration. Concentrations of N-719 and N-749 dyes on solid titania films were successfully extracted using molar extinction coefficients of dye on solid titania films with value of 6916 and 6454 L·cmˉ1·molˉ1 respectively determined using the spectral peaks at 512 and 586 nm.
Spectroscopic Studies of Nanocomposites Based on PEO/PVDF Blend Loaded by SWCNTs  [PDF]
Hind Mohammed Alhusiki-Alghamdi, Naziha Suliman Alghunaim
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.64045
Abstract: Novel nanocomposites of PEO/PVDF loaded by different contents of SWCNTs were prepared. From UV-Vis spectra, the estimated values of absorption edge, absorption coefficient, energy of tail and extinction coefficient were calculated. The exponential decay tail at low energy is due to the presence of localized states in the energy band gap. The shift of Raman spectra indicates the possibility of SWCNTs to be attached with OH group in the side chain of polymer molecules. The X-ray measurements indicate that the addition of SWCNTs is a rich amorphous region in polymeric matrices and complete complexation between PEO/PVDF blend and SWCNTs. The SEM images show smooth surface of PEO/PVDF and they become rough with single rod with a good distribution within surface region in polymeric matrices after loading SWCNTs. TEM images showed that SWCNTs were dispersed well in polymeric matrices. The broken ends of nanotubes were showing that the SWCNTs were broken apart rather than from at the fracture surface. The films show some defects like rags on the tube walls. There are some black regions in TEM images attributed to amorphous nature carbon. The prepared nanocomposites are very useful in technical application.
A Concept for a Novel Test for Chemical Parity  [PDF]
Heinz Langhals, Oswald Krotz
Green and Sustainable Chemistry (GSC) , 2018, DOI: 10.4236/gsc.2018.84021
Abstract: Deviations from chemical parity (PV) were evaluated with the search for very small enantiomeric excesses in a racemate prepared from non chiral materials and were detected by means of the circular dichroism (CD). Thus, intensely light-absorbing perylenebiscarboximides were attached to axially chiral biphenyls for the amplification of CD effects by exciton interactions of the adjacent chromophores. A rapidly racemising system was applied for the exclusion of artifacts and compared with an analogous with locked chirally. A very slight enantiomeric excess was detected for the (M) enantiomer. Application of the method for other systems was suggested and relations to natural products discussed.
Spectroscopic Investigation of Modified Single Wall Carbon Nanotube (SWCNT)  [PDF]
S Hussain, P Jha, A Chouksey, R Raman, S.S. Islam, T Islam, P.K Choudhary
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.26063
Abstract: We have investigated the effects of chemical treatment on Single Wall Carbon Nanotube (SWCNT) before and after being modified with HNO3/H2SO4 by Raman, FTIR and UV-Vis-NIR spectroscopy. The results show successful carboxylation of the CNT sidewalls as observed from FTIR and UV-Vis-NIR spectroscopy. This successful functionalization is achieved in 6-8 hrs of refluxing. We also report changes in the first and second order Raman spectra of SWNTs functionalized with oxygenated groups. During the experiment, we observe some important Raman features: Radial breathing mode (RBM), Tangential mode (G-band), and Disordered mode (D-band); which are affected due to the chemical oxidation of carbon nanotubes. We found that the ratio of D- to the G-band intensity (Id/Ig), increase after functionalization and the RBM mode in acid treated SWCNTs is almost disappeared.
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