WorldWideScience

Sample records for absorption spectrophotometric studies

  1. Determination of spectrophotometric absorptivity by analytical ultracentrifugation

    Directory of Open Access Journals (Sweden)

    M Senthilraja

    2011-01-01

    Full Text Available Rapid determination of the absorptivity for a recombinant IgG monoclonal antibody using the Beckman equipped with both Raleigh interference and UV absorbance optical systems. The analytical ultracentrifuge data for determining spectrophotometric absorptivities is compared to experimental data from quantitative amino acid analysis and an enzymatic digestion method.

  2. Novel atomic absorption spectrometric and rapid spectrophotometric methods for the quantitation of paracetamol in saliva: Application to pharmacokinetic studies

    Directory of Open Access Journals (Sweden)

    Issa M

    2008-01-01

    Full Text Available A novel atomic absorption spectrometric method and two highly sensitive spectrophotometric methods were developed for the determination of paracetamol. These techniques based on the oxidation of paracetamol by iron (III (method I; oxidation of p-aminophenol after the hydrolysis of paracetamol (method II. Iron (II then reacts with potassium ferricyanide to form Prussian blue color with a maximum absorbance at 700 nm. The atomic absorption method was accomplished by extracting the excess iron (III in method II and aspirates the aqueous layer into air-acetylene flame to measure the absorbance of iron (II at 302.1 nm. The reactions have been spectrometrically evaluated to attain optimum experimental conditions. Linear responses were exhibited over the ranges 1.0-10, 0.2-2.0 and 0.1-1.0 µg/ml for method I, method II and atomic absorption spectrometric method, respectively. A high sensitivity is recorded for the proposed methods I and II and atomic absorption spectrometric method value indicate: 0.05, 0.022 and 0.012 µg/ml, respectively. The limit of quantitation of paracetamol by method II and atomic absorption spectrometric method were 0.20 and 0.10 µg/ml. Method II and the atomic absorption spectrometric method were applied to demonstrate a pharmacokinetic study by means of salivary samples in normal volunteers who received 1.0 g paracetamol. Intra and inter-day precision did not exceed 6.9%.

  3. SPECTROPHOTOMETRIC, ATOMIC ABSORPTION AND CONDUCTOMETRIC ANALYSIS OF TRAMADOL HYDROCHLORIDE

    Directory of Open Access Journals (Sweden)

    Sara M. Anis

    2011-09-01

    Full Text Available Six simple and sensitive spectroscopic and conductometric procedures (A-F were developed for the determination of tramadol hydrochloride. Methods A, B and C are based on the reaction of cobalt (II thiocyanate with tramadol to form a stable ternary complex, which could be measured by spectrophotometric (method A, atomic absorption (method B or conductometric (method C procedures. Methods D and E depend on the reaction of molybdenum thiocyanate with tramadol to form a stable ternary complex, measured by spectrophotometric means (method D or by atomic absorption procedures (method E, while method F depends on the formation of an ion pair complex between the studied drug and bromothymol blue which is extractable into methylene chloride. Tramadol hydrochloride could be assayed in the range of 80-560 and 40-–220 μg ml-1, 1-15 mg ml-1 and 2.5-22.5, 1.25-11.25 and 5-22 μg ml-1 using methods A,B,C,D,E and F, respectively. Various experimental conditions were studied. The results obtained showed good recoveries. The proposed procedures were applied successfully to the analysis of tramadol in its pharmaceutical preparations and the results were favorably comparable with the official method.

  4. Spectrofluorimetric, Atomic Absorption Spectrometric and Spectrophotometric Determination of Some Fluoroquinolones

    Directory of Open Access Journals (Sweden)

    Hesham Salem

    2005-01-01

    Full Text Available Simple, accurate, sensitive and selective spectrofluorimetric, atomic absorption spectrometric and spectrophotometric methods are described for the quantitative determination of ten fluoroquinolones (amifloxacin, ciprofloxacin hydrochloride, difloxacin hydrochloride, enoxacin, enrofloxacin, lomefloxacin hydrochloride, levofloxacin, norfloxacin, ofloxacin and pefloxacin mesylate. The first method was a spectrofluorimetric method in which samples of the studied drugs in 0.1 N H2SO4 showed native fluorescence at 450 nm when excitation was at 290 nm. The calibration graph was rectilinear from 0.3-1.4 μg mL-1 (method I. Cobalt sulphate was used for precipitation of the ion associates formed from the reaction with the cited drugs. The formation and solubility of the solid complexes at the optimum conditions of pH and ionic strength values have been studied. The method depends on direct determination of the ions in the precipitate or indirect determination of the ions in the filtrate by atomic absorption spectroscopy. The optimum conditions for precipitation were carefully studied. Rectilinear calibration graphs were obtained in the range of 3-30 μg mL-1 for each of the investigated drugs. The molar ratios of the formed chelats were determined by Job's method and their association constants were also calculated (method II. Ammonium vanadate was used for the spectrophotometric determination of the selected fluoroquinolones by oxidation in sulphuric acid medium resulting in the development of a greenish blue colour measured at 766 nm which was attributed to the vanadium (IV produced by reduction of vanadium (V by the selected drugs. The optimum conditions for heating time, reagent concentration and sulphuric acid concentration were carefully studied. The accuracy and precision of the proposed method was confirmed by estimating five or six replicates within Beer's law limits were obtained in the range 10-40 μg mL-1 for each of the investigated drugs

  5. Raman and absorption spectrophotometric studies of selected lanthanide, californium-doped lanthanide, and actinide trihalides in the solid state

    International Nuclear Information System (INIS)

    The solid-state absorption spectra of Cf(III) ions as a dopant in lanthanide trihalide hosts (LnCl3: Ln = Ce, Sm, and Y; LnBr3: Ln = Ce, Sm, Tb, and Y; LnI3: Ln = Ce and Y) have been recorded. The spectra of Cf(III) have been correlated with the various crystal structures. The phonon Raman spectra and solid-state absorption spectra of PmF3, PmCl3, PmBr3, and two crystal modifications of PmI3 have been recorded. Symmetry assignments have been made for the Raman-active bands for these trihalides and also the sesquioxide. The room-temperature absorption spectra have been correlated to crystal field effects. The symmetry assignments of the Raman-active phonon modes have been made based on polarized Raman spectra from single crystals of YF3-type orthorhombic TbF3 and PuBr3-type orthorhombic NdBr3. Raman spectra of other isostructural lanthanide compounds have been recorded and compared. Symmetry assignments for these compounds have been made by analogy to the single-crystal assignments. Raman spectra have been obtained and catalogued for a number of actinide compounds. Symmetry assignments have been made for the observed Raman-active phonon bands in this work based on the assignments made for isostructural lanthanide compounds. 29 figs., 22 tabs

  6. Spectrophotometric detection of diethylstilbestrol on the basis of the plasmon resonance absorption of silver nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this study,a spectrophotometric detection method for diethylstilbestrol(DES)was proposed by reducing silver nitrate(AgNO3)to obtain silver nanoparticles(AgNPs)in the medium of ammonia and sodium hydroxide.It was found that the resulting AgNPs have plasmon resonance absorption(PRA)characteristic at 415 nm,and the PRA is proportional to the increase of DES concentration in the range of 4.0×10-8-1.0×10-5M with the detection limit(3σ)of 1.2×10-7M.Most of the coexisting substances at high concentrations did n...

  7. Spectrophotometric study of lanthanoid complexes with antipyrine and salicylic acid

    International Nuclear Information System (INIS)

    The extraction-spectrophotometric method has been used to study lanthanoid ion complexing (Pr, Nd, Ho and Er) with antipyrine (Ant) and salicylic acid (Sal). The component relationship in different-ligand compounds Ln:Aut:Sal=2:3:6 and solvate number equal to 5 are determined; molar extinction coefficients of binary and different-ligand compounds are calculated. Oscillator strengths of absorption bands corresponding to supersensitive transitions of neodymium, holmium, erbium and some most intensive praseodymium bands are calculated. The study of IR spectra of investigated compounds allows to conclude on formation of coordination bonds of the central atom with the antipyrine molecule through the oxygen of the carbonyl group as well as on carboxyl group hydrogen substitution for metal and formation of coordination bond with OH group in salicylic acid molecules

  8. SPECTROPHOTOMETRIC STUDIES OF SANGUINARINE-Β-CYCLODEXTRIN COMPLEX FORMATION

    Directory of Open Access Journals (Sweden)

    Veaceslav Boldescu

    2008-06-01

    Full Text Available The main aim of this study was to investigate the influence of pH and the presence of hydrophilic polymer polyvinylpyrrolidone on the formation of sanguinarine-β-cyclodextrin (SANG-β-CD inclusion complex. Spectrophotometric studies of the SANG-β-CD systems in the presence and without 0.1 % PVP at the pH 5.0 did not show any evidence of the complex formation. However, the same systems showed several obvious evidences at the pH 8.0: the hyperchromic and the hypochromic effects and the presence of the isosbestic point in the region of 200 – 210 nm. The association constants calculated by three linear methods: Benesi-Hildebrand, Scott and Scatchard, were two times higher for the systems with addition of 0.1% PVP than for the systems without it.

  9. Spectrophotometric Study on the Interaction of Water with Chloranilic Acid and its Analytical Application

    Institute of Scientific and Technical Information of China (English)

    Feng Lin ZHAO; Xi Lan FENG; Xue Jing LIU; Na LI; Ke An LI

    2005-01-01

    The reaction between chloranilic acid and water in alcohol was studied spectrophotometrically. The conditions of reaction were investigated in detail. The stable purple complex with an absorption wavelength at 530 nm was produced from the reaction between chloranilic acid and water. As a method for determination of H2O, Beer's law was obeyed in range of 0-6.0% or 0-8.0% (V/V) with the detection limit of 0.13%. The relative standard deviation (RSD) was less than 2%. The proposed method has been applied to determination of trace amount of water in ethanol, flour and food flavoring, respectively. The recoveries of water in samples were 97~102%.

  10. Study of reduction of chromium (VI by calcium polysulfide using spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Batukhan Tatykaev

    2013-05-01

    Full Text Available The paper presents  the results of the study on reduction  of  Cr2O72-   to   Cr3 +  by aqueous solution of calcium polysulfide  using spectrophotometric method. Concentrations  of Cr (VI were determined on the basis of the absorption spectrum at the wavelength range 350 - 372 nm. The change of the concentration of Cr (VI during on reduction by calcium polysulfide has been shown.  The influence of pH on the rate of reducing of Cr (VI to Cr (III was considered: the rate of reducing of hexavalent chromium decreases with increasing pH. The data obtained show that recycling Cr (VI in industrial scale potentially effective at  the pH = 5.

  11. Novel ratio difference at coabsorptive point spectrophotometric method for determination of components with wide variation in their absorptivities

    Science.gov (United States)

    Saad, Ahmed S.; Abo-Talib, Nisreen F.; El-Ghobashy, Mohamed R.

    2016-01-01

    Different methods have been introduced to enhance selectivity of UV-spectrophotometry thus enabling accurate determination of co-formulated components, however mixtures whose components exhibit wide variation in absorptivities has been an obstacle against application of UV-spectrophotometry. The developed ratio difference at coabsorptive point method (RDC) represents a simple effective solution for the mentioned problem, where the additive property of light absorbance enabled the consideration of the two components as multiples of the lower absorptivity component at certain wavelength (coabsorptive point), at which their total concentration multiples could be determined, whereas the other component was selectively determined by applying the ratio difference method in a single step. Mixture of perindopril arginine (PA) and amlodipine besylate (AM) figures that problem, where the low absorptivity of PA relative to AM hinders selective spectrophotometric determination of PA. The developed method successfully determined both components in the overlapped region of their spectra with accuracy 99.39 ± 1.60 and 100.51 ± 1.21, for PA and AM, respectively. The method was validated as per the USP guidelines and showed no significant difference upon statistical comparison with reported chromatographic method.

  12. On-line spectrophotometric method for monitoring weak residual absorption of CaMoO{sub 4} single crystals near the intrinsic luminescence peak

    Energy Technology Data Exchange (ETDEWEB)

    Buzanov, O. A., E-mail: fedorov-metrology@yandex.ru [OAO Fomos-Materials (Russian Federation); Kanevskii, V. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Kornoukhov, V. N. [OAO Fomos-Materials (Russian Federation); Nabatov, B. V.; Nabatov, V. V.; Fedorov, V. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2013-11-15

    The optical and spectral characteristics of isotopically enriched Czochralski-grown {sup 40}Ca{sup 100}MoO{sub 4} single crystals have been investigated. This material is promising for detecting double neutrinoless {beta} decay. The possibility and the technique of spectrophotometric monitoring of weak residual absorption near the intrinsic luminescence peak of this scintillation material, which is designed for developing new-generation detectors of elementary particles, are considered.

  13. Simple and Precise UV Spectrophotometric Method Development for Estimation of Albendazole for Dissolution Study

    Directory of Open Access Journals (Sweden)

    Vipin Kumar Agrawal

    2015-01-01

    Full Text Available Albendazole is a class II drug in biopharmaceutical classification system, so its dissolution study is very difficult because of its low solubility and difficulty during estimation of drug in bulk. The present study deals with UV spectrophotometric method development and validation for estimation of albendazole in bulk form. Albendazole is a benzimidazole derivative with an oral broad spectrum of activity against human and animal helminthes parasites. The drug obeyed the Beer’s law and showed good correlation. It showed absorption maxima at 229nm in 0.1 N HCL with 0.05% sodium lauryl sulphate (SLS. The linearity was observed between 4-20μg/ml. The method was applied for the analysis of the drug in the pure, tablet and suspension forms. The slope and intercept of the equation of the regression line are 0.009 and 0.017 respectively. Correlation coefficient was found to be 0.9996. The results of analysis were validated by recovery studies. The recovery was more than 97%. The method was found to be simple, reliable, rapid, precise, specific and reproducible and can be applied for routine analysis of albendazole in different dosage form and dissolution studies.

  14. Geomorphological and Spectrophotometric Study of Philae Landing Site A

    Science.gov (United States)

    Pajola, M.; La Forgia, F.; Giacomini, L.; Oklay, N.; Massironi, M.; Bertini, I.; Simioni, E.; Marzari, F.; Barbieri, C.; Naletto, G.; Groussin, O.; Lazzarin, M.; Scholten, F.; Preusker, F.; Fornasier, S.; Vincent, J. B.; Sierks, H.

    2015-10-01

    5 finalists, this site has the unique value to provide detailed analysis of the multiple fractures present on its cliff and on the neighboring Hathor. Figure 1: Site A as imaged by the OSIRIS NAC camera on 6 August 2014 at 02:20:12 UT. The distance from the comet center is 117.24 km, the scale is 2.17 m/px. EPSC Abstracts Vol. 10, EPSC2015-526, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress We here present the geomorphological map coupled with the size-frequency distributions of boulders # 2 m located on the different types of terrains here identified, such as outcropping layered terrains, gravitational accumulation deposits, taluses and fine particle deposits. Gravitational slopes, derived through the 67P shape model by assuming uniform density, have been used to characterize and better interpret the various terrains. Moreover, we show the spectrophotometric properties of the area, studied through images taken by OSIRIS NAC with a scale of 50 cm/px. Albedo maps, as well as surface reflectance spectra have been obtained by taking advantage of the shape model and DTM in order to correct for the illumination and observing conditions of the terrain. This multidisciplinary analysis highlights that different types of deposits show different photometric properties.

  15. Simple and Precise UV Spectrophotometric Method Development for Estimation of Albendazole for Dissolution Study

    OpenAIRE

    Vipin Kumar Agrawal; Shashank Chaturvedi; Amresh Gupta

    2015-01-01

    Albendazole is a class II drug in biopharmaceutical classification system, so its dissolution study is very difficult because of its low solubility and difficulty during estimation of drug in bulk. The present study deals with UV spectrophotometric method development and validation for estimation of albendazole in bulk form. Albendazole is a benzimidazole derivative with an oral broad spectrum of activity against human and animal helminthes parasites. The drug obeyed the Beer’s law and showed...

  16. Spectrophotometric determination of total proteins in blood plasma: a comparative study among dye-binding methods

    OpenAIRE

    Dimas Augusto Morozin Zaia; Fábio Rangel Marques; Cássia Thaïs Bussamra Vieira Zaia

    2005-01-01

    A comparative study between the biuret method (standard method for total proteins) and spectrophotometric methods using dyes (Bradford, 3',3",5',5"-tetrabromophenolphthalein ethyl ester-TBPEE, and erythrosin-B) was carried out for the determination of total proteins in blood plasma from rats. Bradford method showed the highest sensitivity for proteins and biuret method showed the lowest. For all the methods, the absorbance for different proteins (BSA, casein, and egg albumin) was measured and...

  17. Identification of phenolic antioxidants in Ipomoea mauritiana jacq. using spectrophotometric and mass spectroscopic studies

    OpenAIRE

    Cheruthazhakkat Sulaiman; Sivadasan Pillai Geetha; Balachandran Indira

    2014-01-01

    Objective: Ipomoea mauritiana is used in both Ayurveda and folk medicine systems. The tuberous roots are known to be diuretic, depurative, carminative, and anthelmintic. The objective of the current study was to identify phenolic antioxidants from I . mauritiana using spectrophotometric and LC-MS analysis. Materials and Methods: An activity-guided fractionation and purification process was used to identify the antioxidative components from I . mauritiana tuber. Dried mature tubers of I. maurit...

  18. EXTRACTIVE SPECTROPHOTOMETRIC STUDIES OF ACETOPHENONE 2’, 4’-DIHYDROXY THIOSEMICARBAZONE WITH IRON

    Directory of Open Access Journals (Sweden)

    P. K. Rana

    2012-10-01

    Full Text Available Acetophenone 2’, 4’-Dihydroxy thiosemicarbazone (APDHTS as a reagent for the extractive spectrophotometric determination of Iron. The reagent APDHTS gave instantaneous and stable violet colour with Iron at pH 5.0. A linear calibration graph over the concentration range 1 ppm to 10 ppm with a 3σ limit of detection of 0.66 ppm was obtained by applying the spectrophotometric method at wavelength 370 nm. The stoichiometry of the complex is established as 1:1 (M: L by Job’s method of continuous variation and confirmed by mole ratio method. The standard deviation and the coefficient of variations are presented. The molar absorptivity and Sandal’s sensitivity of the complex is 0.4469 x 103 L mol-1cm –1 and 0.0125 µg cm-2 respectively. The results of the prescribed procedure applied for the determination of the micro amounts of Fe (III in various synthetic and standard steel samples are presented.

  19. Enhancing prediction power of chemometric models through manipulation of the fed spectrophotometric data: A comparative study

    Science.gov (United States)

    Saad, Ahmed S.; Hamdy, Abdallah M.; Salama, Fathy M.; Abdelkawy, Mohamed

    2016-10-01

    Effect of data manipulation in preprocessing step proceeding construction of chemometric models was assessed. The same set of UV spectral data was used for construction of PLS and PCR models directly and after mathematically manipulation as per well known first and second derivatives of the absorption spectra, ratio spectra and first and second derivatives of the ratio spectra spectrophotometric methods, meanwhile the optimal working wavelength ranges were carefully selected for each model and the models were constructed. Unexpectedly, number of latent variables used for models' construction varied among the different methods. The prediction power of the different models was compared using a validation set of 8 mixtures prepared as per the multilevel multifactor design and results were statistically compared using two-way ANOVA test. Root mean squares error of prediction (RMSEP) was used for further comparison of the predictability among different constructed models. Although no significant difference was found between results obtained using Partial Least Squares (PLS) and Principal Component Regression (PCR) models, however, discrepancies among results was found to be attributed to the variation in the discrimination power of adopted spectrophotometric methods on spectral data.

  20. Enhancing prediction power of chemometric models through manipulation of the fed spectrophotometric data: A comparative study.

    Science.gov (United States)

    Saad, Ahmed S; Hamdy, Abdallah M; Salama, Fathy M; Abdelkawy, Mohamed

    2016-10-01

    Effect of data manipulation in preprocessing step proceeding construction of chemometric models was assessed. The same set of UV spectral data was used for construction of PLS and PCR models directly and after mathematically manipulation as per well known first and second derivatives of the absorption spectra, ratio spectra and first and second derivatives of the ratio spectra spectrophotometric methods, meanwhile the optimal working wavelength ranges were carefully selected for each model and the models were constructed. Unexpectedly, number of latent variables used for models' construction varied among the different methods. The prediction power of the different models was compared using a validation set of 8 mixtures prepared as per the multilevel multifactor design and results were statistically compared using two-way ANOVA test. Root mean squares error of prediction (RMSEP) was used for further comparison of the predictability among different constructed models. Although no significant difference was found between results obtained using Partial Least Squares (PLS) and Principal Component Regression (PCR) models, however, discrepancies among results was found to be attributed to the variation in the discrimination power of adopted spectrophotometric methods on spectral data. PMID:27235828

  1. Determination of trace elements in Egyptian cane sugar (Deshna Factories) by neutron activation, atomic absorption spectrophotometric and inductively coupled plasma-atomic emission spectrometric analysis

    International Nuclear Information System (INIS)

    Multielement instrumental neutron activation (INAA), inductively coupled plasma-atomic emission spectrometric (ICP-AES) and atomic absorption spectrophotometric (AAS) analyses were utilized for the determination of Ag, Al, As, Au, Ba, Be, Br, Ca, Cd, Ce, Cl, Co, Cr, Cu, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, P, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in sugar cane plant, raw juice, juice in different stages, syrup, deposits, molasses, A, B and C sugar, refinery 1 and 2 sugar, and in soil samples picked up from the immediate vicinity of the cane plant roots at surface, 30 and 60 cm depth, respectively. (author)

  2. Spectrophotometric study of bio-sorption of uranium on glass grade spodumene shell powder

    International Nuclear Information System (INIS)

    Separation of uranium found in iron ore leachates was done by extraction chromatography using glass grade spodumene shellpowder (GSS) in nitric acid medium and analyzed spectrophotometrically. The influences of metal ion concentration, pH and adsorption capacity of biomass were investigated. Biosorption is a potential method of separation of heavy and trace metals from waste water and effluents from various sources. The adsorption capacities of biomass were investigated by batch experiments and column experiments. In the present study, glass grade spodumene shell powder (GSS) in acidic medium is being used as a biosorbent

  3. Spectrophotometric study of neptunium (VI) complexation by nitrate ions

    International Nuclear Information System (INIS)

    Neptunium(VI) complexation by nitrate ions was investigated by visible and near-infrared spectrophotometry, a technique suitable for observing the appearance and evolution of the species in solution. In the absence of reference spectra for Np(VI) nitrate- complexes, mathematical (factor analysis) tools were used to interpret the spectra. These chemo-metric techniques were first tested and validated on a simpler chemical system: Np(VI)complexation by the SiW11O398- anion. The test media used to investigate Np(VI) nitrate- complexes generally contain nitrate and perchlorate salts at high concentrations (high ionic strength). Media effects arising from the presence of cations, acidity or the perchlorate ion concentration are therefore significant, and no doubt account for the scattered values of the complexation constants published in the literature. The evolution of the neptunium spectra according to the parameters of the reaction medium illustrated these effects and allowed them to be quantified by a global 'perturbation constant'. In order to minimize the spectrum modifications due to media effects, the neptunium nitrate-complexes were studied at constant ionic strength in weak acidic media (2 mol.kg-1H2O) in the presence of sodium salts. The bulk formation constants and the spectrum of the NpO2(NO3)+ complex were determined for ionic strength values of 2.2, 4, 6 and 8 mol.kg-1H2O. The constants remained on the same order of magnitude regardless of the ionic strength; the thermodynamic constant β10 determined from them according to specific interaction theory is thus probably of little significance. Conversely, the bulk constants can be corrected for the effects of the perchlorate ions by taking the global 'perturbation constant' into account. (author)

  4. Flow analysis-hydride generation-gas phase derivative molecular absorption spectrophotometric determination of antimony in antileishmanial drugs

    Directory of Open Access Journals (Sweden)

    Máximo Gallignani

    2009-01-01

    Full Text Available In the present work, the development of a method based on the coupling of flow analysis (FA, hydride generation (HG, and derivative molecular absorption spectrophotometry (D-EAM in gas phase (GP, is described in order to determine total antimony in antileishmanial products. Second derivative order (D²224nm of the absorption spectrum (190 - 300 nm is utilized as measurement criterion. Each one of the parameters involved in the development of the proposed method was examined and optimized. The utilization of the EAM in GP as detection system in a continuous mode instead of atomic absorption spectrometry represents the great potential of the analytic proposal.

  5. Comparative study on the selectivity of various spectrophotometric techniques for the determination of binary mixture of fenbendazole and rafoxanide.

    Science.gov (United States)

    Saad, Ahmed S; Attia, Ali K; Alaraki, Manal S; Elzanfaly, Eman S

    2015-11-01

    Five different spectrophotometric methods were applied for simultaneous determination of fenbendazole and rafoxanide in their binary mixture; namely first derivative, derivative ratio, ratio difference, dual wavelength and H-point standard addition spectrophotometric methods. Different factors affecting each of the applied spectrophotometric methods were studied and the selectivity of the applied methods was compared. The applied methods were validated as per the ICH guidelines and good accuracy; specificity and precision were proven within the concentration range of 5-50 μg/mL for both drugs. Statistical analysis using one-way ANOVA proved no significant differences among the proposed methods for the determination of the two drugs. The proposed methods successfully determined both drugs in laboratory prepared and commercially available binary mixtures, and were found applicable for the routine analysis in quality control laboratories.

  6. Study of Ascorbic Acid as Iron(III Reducing Agent for Spectrophotometric Iron Speciation

    Directory of Open Access Journals (Sweden)

    Antesar Elmagirbi

    2012-10-01

    Full Text Available The study of ascorbic acid as a reducing agent for iron(III has been investigated in order to obtain an alternative carcinogenic reducing agent, hydroxylamine, used in spectrophotometric standard method based on the formation of a red-orange complex of Fe(II-o-phenanthroline. The study was optimised with regards to ascorbic acid concentration as well as pH solution. The results showed that ascorbic acid showed maximum capacity as reducing agent of iron(III under concentration of 4.46.10-4 M and pH solution of 1-4.Under these conditions, ascorbic acid reduced iron(III proportionally and performed similarly to that of hydroxylamine.  The method gave result to linear calibration over the range of 0.2-2 mg/L withhigh accuracy of 97 % and relative standard deviation of less than 2 %. This method was successfully applied to assay iron speciation in water samples.

  7. UV Spectrophotometric Method for Determination of Cinitapride in Pure and its Solid Dosage Form

    OpenAIRE

    B. Thangabalan; A. Elphine Prabahar; R. Kalaichelvi; P. Vijayaraj Kumar

    2009-01-01

    A new, rapid, precise, accurate and sensitive analytical method was developed for the UV spectrophotometric assay of cinitapride (CTP). The drug obeyed the Beer's law and showed good correlation. It showed absorption maxima at 260 nm in methanol. The linearity was observed between 5-40 µg mL-1. The results of analysis were validated by recovery studies. The recovery was more than 99%. The proposed method is the only method available for spectrophotometric determination of the drug. It is simp...

  8. Measurement of Capsaicinoids in Chiltepin Hot Pepper: A Comparison Study between Spectrophotometric Method and High Performance Liquid Chromatography Analysis

    Directory of Open Access Journals (Sweden)

    Alberto González-Zamora

    2015-01-01

    Full Text Available Direct spectrophotometric determination of capsaicinoids content in Chiltepin pepper was investigated as a possible alternative to HPLC analysis. Capsaicinoids were extracted from Chiltepin in red ripe and green fruit with acetonitrile and evaluated quantitatively using the HPLC method with capsaicin and dihydrocapsaicin standards. Three samples of different treatment were analyzed for their capsaicinoids content successfully by these methods. HPLC-DAD revealed that capsaicin, dihydrocapsaicin, and nordihydrocapsaicin comprised up to 98% of total capsaicinoids detected. The absorbance of the diluted samples was read on a spectrophotometer at 215–300 nm and monitored at 280 nm. We report herein the comparison between traditional UV assays and HPLC-DAD methods for the determination of the molar absorptivity coefficient of capsaicin (ε280=3,410 and ε280=3,720 M−1 cm−1 and dihydrocapsaicin (ε280=4,175 and ε280=4,350 M−1 cm−1, respectively. Statistical comparisons were performed using the regression analyses (ordinary linear regression and Deming regression and Bland-Altman analysis. Comparative data for pungency was determined spectrophotometrically and by HPLC on samples ranging from 29.55 to 129 mg/g with a correlation of 0.91. These results indicate that the two methods significantly agree. The described spectrophotometric method can be routinely used for total capsaicinoids analysis and quality control in agricultural and pharmaceutical analysis.

  9. Radiometric and spectrophotometric studies of the behavior of chromium(VI) oxide in concentrated perchloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Pezzin, S.H.; Collins, C.H.; Collins, K.E. [Universidade Estadual de Campinas (Brazil). Inst. de Quimica; Archundia, C. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias Nucleares

    1997-11-01

    A study of the behavior of {sup 51}CrO{sub 3} in 70% HClO{sub 4} over the temperature range from 20 to 194 C by means of Cr-51 labelling, UV-VIS spectrophotometry and ion exchange chromatography, shows that the solubility of {sup 51}CrO{sub 3} depends on a competition between the dissolution process and the acid reduction of solution phase Cr(VI). These processes occur simultaneously and are dependent on both the temperature and the concentration of Cr(VI), as shown by comparison between radiometric measurements (where total chromium can be accurately determined) and spectrophotometric measurements (where only the Cr(VI) is detectable at the wavelengths studied). These conclusions are confirmed by PbCrO{sub 4} precipitation of {sup 51}Cr(VI), where at 194 C, 97% of the total chromium appears as Pb{sup 51}CrO{sub 4} while at 86 C only 5% does. Cation exchange chromatography of the solution after brief contact of {sup 51}CrO{sub 3} with concentrated HClO{sub 4} at 20 C shows only traces of {sup 51}Cr(VI), most of the radioactivity eluting as {sup 51}Cr(H{sub 2}O){sup 3+}{sub 6}, with smaller amounts of species with +2 and +1 charges. These results imply serious limitations to the spectrophotometric determination of low concentrations of total chromium in alloys or in biological material which use dissolution in 70% HClO{sub 4} as a primary analytical step. (orig.)

  10. Spectrophotometric determination of association constant

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charge...

  11. Spectrophotometric study of the samarium nitrate-water-dimethyl sulfoxide system

    International Nuclear Information System (INIS)

    Effect of water-dimethyl sulfoxide solvent composition (DMSO) on samarium (3) ion electron absorption spectrum is studies. It is shown, that the absorption maximum ware length λ and the molar absorption coefficient K of samarium (3) ion grow cymbately with the increase of DMSO molar shave (N) in water-DMSO solvent. It is ascertained that these dependences possess a bending point at N=0.5. A conclusion is made, that samarium ions with different solvate coating are present in the solution at the same time; on the average, the member of water and DMSO molecules in the ion solvate coating corresponds to their molar share in the solvent composition

  12. Determination of Cyproheptadine hydrochloride in Pure and Pharmaceutical forms : A Spectrophotometric study

    Directory of Open Access Journals (Sweden)

    Sayanna

    2015-09-01

    Full Text Available Siimple and sensitive extractive spectrophotometric methods have been described for the determination of Cyproheptadine hydrochloride (CPH in pure form and in pharmaceutical formulations. The developed methods involved formation of coloured chloroform extractable ion-pair complexes of the CPH with triphenyl methane dyes viz., bromothymol blue (BTB, bromocresol green (BCG and bromocresol purple (BCP in acidic medium. The extracted complexes showed absorbance maxima at 419, 419 and 405nm with use of the above dyes, respectively. Beer’s law is obeyed in the concentration ranges 3.0-25, 2.5-22.5 and 1.5-25μg/ml with BTB, BCG and BCP respectively. The stoichiometry of the complex is found to be 1:1 in each case. The effect of concentration of dye, pH and interference of excipients have been studied and optimized. The limit of detection and limit of quantification have been determined for three methods. The methods are applied to the determination of CPH in commercial tablets and results of analysis are validated statistically through recovery studies also the methods are validated as per the guidelines of ICH.

  13. Studies on Tinospora cordifolia monosugars and correlation analysis of uronic acids by spectrophotometric methods and GLC.

    Science.gov (United States)

    Kumar, Vineet; Nagar, Shipra

    2014-01-01

    Cold water-soluble (CWSP) and hot water soluble polysaccharides (HWSP) from Tinospora cordifolia stems were isolated and purified in 2.99% and 1.99% yield respectively. Complete hydrolysis followed by paper chromatography and GLC analysis indicated the presence of L-rhamnose, L-arabinose, D-xylose, D-mannose, D-galactose and D-glucose in molar ratio of 0.857, 1.106, 0.727, 0.526, 0.708 and 95.763 in CWSP and 0.697, 0.777, 2.048, 0.777, 0.292 and 95.408 in HWSP. The uronic acid content in the polysaccharide has been studied extensively using assorted approaches. It was quantitatively estimated by GLC analysis and spectrophotometric methods using carbazole, m-hydroxydiphenyl and 3,5-dimethylphenol as colorimetric reagents. GLC analyses indicated galacturonic acid content of 3.06% and 5.16% in CWSP and HWSP respectively. Estimation of uronic acid using 3,5-dimethylphenol corroborated the above analysis. The study resulted in composition of constituent monosugars of CWSP and HWSP and co-relation analysis of uronic acid content, leading to an unambiguous structural analysis. PMID:24274509

  14. Study on the spectrophotometric detection of free fatty acids in palm oil utilizing enzymatic reactions.

    Science.gov (United States)

    Azeman, Nur Hidayah; Yusof, Nor Azah; Abdullah, Jaafar; Yunus, Robiah; Hamidon, Mohd Nizar; Hajian, Reza

    2015-07-07

    In this paper, a comprehensive study has been made on the detection of free fatty acids (FFAs) in palm oil via an optical technique based on enzymatic aminolysis reactions. FFAs in crude palm oil (CPO) were converted into fatty hydroxamic acids (FHAs) in a biphasic lipid/aqueous medium in the presence of immobilized lipase. The colored compound formed after complexation between FHA and vanadium (V) ion solution was proportional to the FFA content in the CPO samples and was analyzed using a spectrophotometric method. In order to develop a rapid detection system, the parameters involved in the aminolysis process were studied. The utilization of immobilized lipase as catalyst during the aminolysis process offers simplicity in the product isolation and the possibility of conducting the process under extreme reaction conditions. A good agreement was found between the developed method using immobilized Thermomyces lanuginose lipase as catalyst for the aminolysis process and the Malaysian Palm Oil Board (MPOB) standard titration method (R2 = 0.9453).

  15. A spectrophotometric study of cerium IV and chromium VI species in nuclear fuel reprocessing process streams

    Science.gov (United States)

    Nickson, I. D.; Boxall, C.; Jackson, A.; Whillock, G. O. H.

    2010-03-01

    Nuclear fuel reprocessing schemes such as PUREX and UREX utilise HNO3 media. An understanding of the corrosion of process engineering materials such as stainless steel in such media is a major concern for the nuclear industry. Two key species are cerium and chromium which, as Ce(IV), Cr(VI), may act as corrosion accelerants. An on-line analytical technique for these quantities would be useful for determining the relationship between corrosion rate and [Ce(IV)] and [Cr(VI)]. Consequently, a strategy for simultaneous quantification of Ce(IV), Cr(VI) and Cr(III) in the presence of other ions found in average burn-up Magnox / PWR fuel reprocessing stream (Fe, Mg, Nd, Al) is being developed. This involves simultaneous UV-vis absorbance measurement at 620, 540, 450 nm, wavelengths where Ce and Cr absorb but other ions do not. Mixed solutions of Cr(VI) and Ce(IV) are found to present higher absorbance values at 540 nm than those predicted from absorbances recorded from single component solutions of those ions. This is attributed to the formation of a 3:1 Cr(VI)-Ce(IV) complex and we report on the complexation and UV-visible spectrophotometric characteristics of this species. To the best of our knowledge this is the first experimental study of this complex in aqueous nitric acid solution systems.

  16. Identification of phenolic antioxidants in Ipomoea mauritiana jacq. using spectrophotometric and mass spectroscopic studies

    Directory of Open Access Journals (Sweden)

    Cheruthazhakkat Sulaiman

    2014-02-01

    Full Text Available Objective: Ipomoea mauritiana is used in both Ayurveda and folk medicine systems. The tuberous roots are known to be diuretic, depurative, carminative, and anthelmintic. The objective of the current study was to identify phenolic antioxidants from I. mauritiana using spectrophotometric and LC-MS analysis. Materials and Methods: An activity-guided fractionation and purification process was used to identify the antioxidative components from I. mauritiana tuber. Dried mature tubers of I. mauritiana were extracted with 80% methanol and then partitioned by chloroform, ethyl acetate, acetone, and methanol. The acetone fraction showed the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH radical scavenging activity among four fractions and was subjected to separation and purification using preparative reverse-phase high-performance liquid chromatography (HPLC. Results: Two compounds were separated from the acetone fraction using preparative LC fraction collector. The purified compounds were screened for their antioxidative potential using DPPH assay. The compounds were subjected to LC-MS analysis in ESI negative mode. One of the compounds was identified as Caffeoyl glucose based on the mass fragmentation. Conclusion: The acetone fraction showed highest radical scavenging activity and the phytoconstituents of the same were identified by LC-MS/MS analysis.

  17. EXTRACTIVE SPECTROPHOTOMETRIC STUDIES OF ACETOPHENONE 2’, 4’-DIHYDROXY THIOSEMICARBAZONE WITH IRON

    OpenAIRE

    P. K. Rana; R. S. Lokhande; S. M. Pitale; S.P. Janwadkar; P. S. Navarkar; D K Yadav

    2012-01-01

    Acetophenone 2’, 4’-Dihydroxy thiosemicarbazone (APDHTS) as a reagent for the extractive spectrophotometric determination of Iron. The reagent APDHTS gave instantaneous and stable violet colour with Iron at pH 5.0. A linear calibration graph over the concentration range 1 ppm to 10 ppm with a 3σ limit of detection of 0.66 ppm was obtained by applying the spectrophotometric method at wavelength 370 nm. The stoichiometry of the complex is established as 1:1 (M: L) by Job’s method of continuous ...

  18. Complexation of Iron by Dopamine Analogs; A Spectrophotometric and Potentiometric Study

    OpenAIRE

    *T. Fiaz; N. Fatima; S. Z. A. Zaidi

    2013-01-01

    The chelation of Bio-essential metal, Iron, with dopamine analogs was studied at 30±2°C. Fe2+ formed intense color complex with these molecules with an absorbance maxima in visible region. A distinct peak of Fe-Carbidopa complex at 364nm with molar absorptivity of 1600 M-1 cm-1 was observed while that of Fe-Levodopa and Fe-Methyldopa were observed at 730nm with molar absorptivities of 306 M-1 cm-1 and 2300 M-1 cm-1, respectively. Potentiometric studies of the complex indicate that Fe(II) ...

  19. Spectrophotometric Evaluation of the Pulpal Peroxide Levels in Intact and Restored Teeth - An Invitro Study

    Science.gov (United States)

    Acharya, Gourismita; Agrawal, Pratik; Panda, Vijeta

    2016-01-01

    Introduction Hydrogen peroxide (30%) is a commonly used "in office" bleaching agent. Deleterious effects of hydrogen peroxide on the pulp have been observed. Aim The present study was conducted with the aim to evaluate the penetration of 30% hydrogen peroxide into the pulp chamber through intact teeth and through the surface of teeth, restored with either hybrid composite or Resin Modified Glass Ionomer Cement (RMGIC). Materials and Methods Sixty extracted human maxillary central incisors were selected and divided into six groups. Two groups were restored with hybrid composite resin and two with RMGIC, while two groups were left intact. The teeth with acetate buffer solution in their pulp cavity were then immersed in either 30% hydrogen peroxide or distilled water depending upon the group, for 60 minutes at 37°C. Then horseradish peroxidase and leucocrystal violet were added to the acetate buffer solution present in the pulp chamber after it was transferred to a test tube and the optical density of the resultant blue solution obtained was measured spectrophotometrically. Statistical Analysis The data obtained were analyzed using one way ANOVA and Student’s t-test. Results The data obtained established that hydrogen peroxide penetrated into the pulp from the bleaching agent used. Hydrogen peroxide (30%) showed the highest pulpal peroxide level in teeth restored with RMGIC followed by teeth restored with hybrid composite resin and the least amount of penetration was observed in intact teeth. Conclusion The amount of peroxide penetration into the tooth is more through restored tooth than intact tooth and is also dependant on the type of restorative materials used. PMID:27656562

  20. A comparative study of novel spectrophotometric methods based on isosbestic points; application on a pharmaceutical ternary mixture.

    Science.gov (United States)

    Lotfy, Hayam M; Saleh, Sarah S; Hassan, Nagiba Y; Salem, Hesham

    2014-05-21

    This work represents the application of the isosbestic points present in different absorption spectra. Three novel spectrophotometric methods were developed, the first method is the absorption subtraction method (AS) utilizing the isosbestic point in zero-order absorption spectra; the second method is the amplitude modulation method (AM) utilizing the isosbestic point in ratio spectra; and third method is the amplitude summation method (A-Sum) utilizing the isosbestic point in derivative spectra. The three methods were applied for the analysis of the ternary mixture of chloramphenicol (CHL), dexamethasone sodium phosphate (DXM) and tetryzoline hydrochloride (TZH) in eye drops in the presence of benzalkonium chloride as a preservative. The components at the isosbestic point were determined using the corresponding unified regression equation at this point with no need for a complementary method. The obtained results were statistically compared to each other and to that of the developed PLS model. The specificity of the developed methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. PMID:24589996

  1. Spectrophotometric Study of the Effect of a Magnetic Field on Human Blood Components

    Science.gov (United States)

    Kazin, V. N.; Makaryin, V. V.; Guzov, E. A.; Moshareva, V. A.; Kovchiy, K. A.

    2016-07-01

    We have used electronic spectroscopy and optical aggregometry to study the effect of a constant magnetic fi eld on blood components. Based on the absorption spectra, we observe a decrease in optical density for both plasma and whole blood samples. Based on the results of platelet aggregation studies, we identifi ed two groups of test subjects with opposite types of responses to exposure to a magnetic fi eld. The observed behavior is probably associated with changes in the spatial structure of the proteins.

  2. Different spectrophotometric methods applied for the analysis of binary mixture of flucloxacillin and amoxicillin: A comparative study

    Science.gov (United States)

    Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

    2016-05-01

    Three different spectrophotometric methods were applied for the quantitative analysis of flucloxacillin and amoxicillin in their binary mixture, namely, ratio subtraction, absorbance subtraction and amplitude modulation. A comparative study was done listing the advantages and the disadvantages of each method. All the methods were validated according to the ICH guidelines and the obtained accuracy, precision and repeatability were found to be within the acceptable limits. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. So, they can be used for the routine analysis of flucloxacillin and amoxicillin in their binary mixtures.

  3. Spectrophotometric determination of total proteins in blood plasma: a comparative study among dye-binding methods

    Directory of Open Access Journals (Sweden)

    Dimas Augusto Morozin Zaia

    2005-05-01

    Full Text Available A comparative study between the biuret method (standard method for total proteins and spectrophotometric methods using dyes (Bradford, 3',3",5',5"-tetrabromophenolphthalein ethyl ester-TBPEE, and erythrosin-B was carried out for the determination of total proteins in blood plasma from rats. Bradford method showed the highest sensitivity for proteins and biuret method showed the lowest. For all the methods, the absorbance for different proteins (BSA, casein, and egg albumin was measured and Bradford method showed the lowest variation of absorbance. The concentration of total protein obtained by using Bradford method was not statistically different (p>0.05 from concentration of total protein obtained by the biuret method. But in regard to erythrosin-B and TBPEE methods the concentrations of total protein were statistically different (pA determinação de proteínas totais em plasma sangüíneo é importante em diversas áreas de pesquisa. Um estudo comparativo entre o método de biureto (método padrão para proteínas totais e diversos métodos que utilizam corantes (Bradford, tetrabromofenolftaleína etil éster-TBPEE, e eritrosina-B foi realizado para a determinação de proteínas totais em plasma sangüíneo de ratos. O método de Bradford mostrou a maior sensibilidade para proteínas e o de biureto a menor. Para todos os métodos, as absorbâncias para diferentes proteínas (BSA, caseína, e ovoalbumina foram medidas e o método de Bradford mostrou a menor variação da absorbância. Utilizando o método de Bradford a concentração de proteínas totais obtida não foi estatisticamente diferente (p>0.05 daquela obtida pelo método do biureto. Porém, para os métodos da eritrosina-B e TBPEE as concentrações de proteínas totais foram estatisticamente diferentes (p<0.05 da obtida pelo método de biureto. Portanto o método de Bradford pode ser utilizado no lugar do método de biureto para a determinação de proteínas totais em plasma sangüíneo.

  4. SPECTROPHOTOMETRIC ESTIMATION OF GEMFIBROZIL IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    Parikh Vikas C.

    2011-06-01

    Full Text Available A simple, sensitive and accurate UV spectrophotometric method has been developed for the determination of Gemfibrozil in bulk and pharmaceutical tablet dosage formulation. This method obeys Beer’s law in the concentration range of 30-90 µg/ml. with correlation coefficient of 0.9993 and exhibiting maximum absorption at 276 nm with apparent molar absorptivity of 0.1703 × 104 L mole-1 cm-1. The method is accurate and precise and is extended to pharmaceutical tablet dosage forms and there was no interference from any common pharmaceutical additives and excipients. The results of analysis were validated statistically and by recovery studies.

  5. Validation of UV spectrophotometric methods for the determination of dothiepin hydrochloride in pharmaceutical dosage form and stress degradation studies

    Science.gov (United States)

    Abdulrahman, Sameer A. M.; Basavaiah, K.; Cijo, M. X.; Vinay, K. B.

    2012-11-01

    Spectrophotometric methods have been developed for the determination of dothiepin hydrochloride (DOTH) in both pure and tablet dosage form and their limits of detection and quantification have been evaluated. The methods are based on the measurement of the absorbance of a DOTH solution either in 0.1 N HCl at 229 nm (method A) or in methanol at 231 nm (method B). Beer's law is obeyed over a concentration range of 1-16 μg/ml DOTH for both methods. Molar absorptivity values are calculated to be 2.48 × 104 and 2.42 × 104 l/(mol × cm) with Sandell sensitivity values of 0.0134 and 0.0137 μg/cm2 for methods A and B, respectively. The degradation behavior of DOTH was investigated under different stress conditions such as acid hydrolysis, alkaline hydrolysis, water hydrolysis, oxidation, dry heat treatment, and UV-degradation. The drug undergoes significant degradation under oxidative conditions only.

  6. Spectrophotometric and Voltammetric Studies on the Interaction of Heparin with Phenosafranine

    Institute of Scientific and Technical Information of China (English)

    Wei SUN; Ya Qin DING; Kui JIAO

    2005-01-01

    The interaction of phenosafranine (PSF) with a glycosaminoglycans of heparin (Hep) in aqueous solution has been characterized by UV-Vis absorption spectrophotometry and cyclic voltammetry in pH 1.5 Britton-Robinson (B-R) buffer solution. The addition of Hep caused decrease of the absorbance of PSF at 532 nm and the redox peak current of PSF. The study showed that an supramolecular complex of PSF-Hep was formed because of the electrostatic attraction of negatively charged Hep with the positively charged PSF, which resulted in the decrease of the equilibrium concentration of PSF in solutions, and the decrease of the absorbance or the Peak current of PSF. The stoichiometry of the Hep/PSF complex was further calculated by voltammetric data with the result of 1:1 complex.

  7. Spectrophotometric studies and applications for the determination of Ni2+ in zinc-nickel alloy electrolyte

    Science.gov (United States)

    Qiao, Xiaoping; Li, Helin; Zhao, Wenzhen; Li, Dejun

    The absorption properties of zinc-nickel alloy electrolyte were studied by visible spectrophotometer. The results show that the relationship between the absorbance of the zinc-nickel alloy electrolyte and Ni2+ concentration in the electrolyte obeys Beer's law at 660 nm. In addition, other components except Ni2+ in the zinc-nickel alloy electrolyte such as zinc chloride, ammonium chloride, potassium chloride and boric acid have no obvious effect on the absorbance of zinc-nickel alloy electrolyte. Based on these properties, a new method is developed to determine Ni2+ concentration in zinc-nickel alloy electrolyte. Comparing with other methods, this method is simple, direct and accurate. Moreover, the whole testing process does not consume any reagent and dilution, and after testing, the electrolyte samples can be reused without any pollution to the environment.

  8. Spectrophotometric and electrochemical study of neptunium ions in molten NaCl–CsCl eutectic

    International Nuclear Information System (INIS)

    The chemical oxidation states of NpO2+, Np4+ and Np3+ in NaCl–CsCl eutectic were controlled by using Cl2, O2, H2 and Ar gas mixtures, the redox behavior and electronic absorption properties of their Np ions were studied. The Np4+ was prepared from NpO2Cl by bubbling Cl2 gas into the melt in the presence of carbon rod. Np3+ was quantitatively prepared by bubbling H2–Ar gas mixture. The molar absorptivities of NpO2+, Np4+ and Np3+ were determined in molten NaCl–CsCl eutectic at 923 K and hypersensitive transitions of Np4+ and Np3+ ions were assigned. Since the polarizing ability of the cations in the NaCl–CsCl eutectic is lower than that in some other melts, it has been shown that the coordination symmetry of the Np–Cl complex is higher. In the electrochemical measurement of Np4+, the cathodic current for the reduction of Np4+ was found to be controlled by the diffusion of Np4+. The temperature dependence of the diffusion coefficient between 823 and 923 K was formulated to be lnDNp4+=-4304/T-6.172. The formal redox potential of the Np4+|Np3+ couple depended on the temperature, this dependence was formulated as ENp4+|Np3+∘′=-1.313+6.210×10-4TV (vs. Cl2|Cl−)

  9. Spectrophotometric determination of benazepril in tablets.

    Science.gov (United States)

    Belal, F; Al-Zaagi, I A; Abounassif, M A

    2000-01-01

    A simple and sensitive spectrophotometric method has been developed for the determination of benazepril HCl in pharmaceutical formulations. The method is based on the reaction of the drug with potassium permanganate in the presence of sodium hydroxide to produce a bluish-green colored species measurable at 609.4 nm. The absorbance-concentration plot is linear over the range 1-8 microg ml(-1) with minimum detectability of 0.1 microg ml(-1) (2.17 x 10(-7) M). The molar absorptivity was 4.07 x 10(4) l mol(-1) cm(-1) with correlation coefficient (n = 6) of 0.9991. The different experimental parameters affecting the development and stability of the color were studied carefully and optimized. The proposed method was applied successfully to the determination of benazepril in its dosage forms, the percentage recoveries +/- SD (n = 9) were 99.79 +/- 1.40 and 100.50 +/- 1.48 for tablets containing 10 and 20 mg, respectively. The results obtained were in good agreement with those obtained using a reference spectrophotometric method. The proposed method could be applied to the determination of benazepril in presence of the co-formulated drug, hydrochlorothiazide. A proposal of the reaction pathway was presented. PMID:11204742

  10. Spectrophotometric method for ondansetron hydrochloride

    OpenAIRE

    Patra Sradhanjali; Choudhury A.; Kar R; Barik B

    2007-01-01

    A new simple, sensitive spectrophotometric method in UV region has been developed for the estimation of ondansetron in bulk and solid dosage form. It shows maximum absorbance at 310 nm with water. Beer′s law obeys in the concentration range of 5-15 µg/ml. Results of the analysis were validated statistically and by recovery studies.

  11. Spectrophotometric method for ondansetron hydrochloride

    Directory of Open Access Journals (Sweden)

    Patra Sradhanjali

    2007-01-01

    Full Text Available A new simple, sensitive spectrophotometric method in UV region has been developed for the estimation of ondansetron in bulk and solid dosage form. It shows maximum absorbance at 310 nm with water. Beer′s law obeys in the concentration range of 5-15 µg/ml. Results of the analysis were validated statistically and by recovery studies.

  12. EVALUATION OF HEAVY METALS IN ETHANOLIC LEAF EXTRACT OF ACACIA CATECHU AS INDICATOR OF POLLUTION BY ATOMIC ABSORPTION SPECTROPHOTOMETRIC (FAAS) ANALYSIS

    OpenAIRE

    Lakshmi T; Rajendran R; Antony silvester

    2013-01-01

    Acacia catechu ethanolic leaf extract were selected to determine their heavy metals content and thereby to assure their safer therapeutic application. The trace and heavy metals were detected through atomic absorption spectrometry analysis. The selected medicinal plant material was procured from green chem herbal extracts, Bangalore, India and was digested with nitric acid and hydrochloric acid as specified. Absorbance was measured through atomic absorption spectrometer (AA 6030) and the conc...

  13. Study on Performance and Mechanism of Oil Absorption Materials

    Institute of Scientific and Technical Information of China (English)

    韩梅; 吴兵; 李发生; 何绪文; 谷庆宝

    2001-01-01

    Both the commonly used and the PHBV based oil absorption materials were studied and the absorption mechanism was analyzed. The results show that the oil pick-up ratios and the absorption rates of molded PHBV are almost the same as that of oil absorption polypropylene felt. In addition, the oil-keeping ability of molded PHBV is superior to the latter. So the PHBV is a valuable and bio-degradable oil absorption material.

  14. A new, fast and accurate spectrophotometric method for the determination of the optical constants of arbitrary absorptance thin films from a single transmittance curve: application to dielectric materials

    Science.gov (United States)

    Desforges, Jean; Deschamps, Clément; Gauvin, Serge

    2015-08-01

    The determination of the complex refractive index of thin films usually requires the highest accuracy. In this paper, we report on a new and accurate method based on a spectral rectifying process of a single transmittance curve. The agreements with simulated and real experimental data show the helpfulness of the method. The case of materials having arbitrary absorption bands at midpoint in spectral range, such as pigments in guest-host polymers, is also encompassed by this method.

  15. EVALUATION OF HEAVY METALS IN ETHANOLIC LEAF EXTRACT OF ACACIA CATECHU AS INDICATOR OF POLLUTION BY ATOMIC ABSORPTION SPECTROPHOTOMETRIC (FAAS ANALYSIS

    Directory of Open Access Journals (Sweden)

    Lakshmi.T

    2013-06-01

    Full Text Available Acacia catechu ethanolic leaf extract were selected to determine their heavy metals content and thereby to assure their safer therapeutic application. The trace and heavy metals were detected through atomic absorption spectrometry analysis. The selected medicinal plant material was procured from green chem herbal extracts, Bangalore, India and was digested with nitric acid and hydrochloric acid as specified. Absorbance was measured through atomic absorption spectrometer (AA 6030 and the concentration of different heavy metals in the plant sample was calculated. The quantitative determinations were carried out using standard calibration curve obtained by the standard solutions of different metals. The contents of heavy metals were found to be within the prescribed limit. Thus, on the basis of experimental outcome, it can be concluded that the plant material is safe and may not produce any harmful effect of metal toxicity during their therapeutic application. The investigated medicinal plants contains heavy metals such as arsenic (As, lead (Pb and mercury (Hg and cadmium (Cd, which were present within the permissible limit.

  16. New Spectrophotometric and Conductometric Methods for Macrolide Antibiotics Determination in Pure and Pharmaceutical Dosage Forms Using Rose Bengal

    Directory of Open Access Journals (Sweden)

    Rania A. Sayed

    2013-01-01

    Full Text Available Two Simple, accurate, precise, and rapid spectrophotometric and conductometric methods were developed for the estimation of erythromycin thiocyanate (I, clarithromycin (II, and azithromycin dihydrate (III in both pure and pharmaceutical dosage forms. The spectrophotometric procedure depends on the reaction of rose bengal and copper with the cited drugs to form stable ternary complexes which are extractable with methylene chloride, and the absorbances were measured at 558, 557, and 560 nm for (I, (II, and (III, respectively. The conductometric method depends on the formation of an ion-pair complex between the studied drug and rose bengal. For the spectrophotometric method, Beer's law was obeyed. The correlation coefficient ( for the studied drugs was found to be 0.9999. The molar absorptivity (, Sandell’s sensitivity, limit of detection (LOD, and limit of quantification (LOQ were also calculated. The proposed methods were successfully applied for the determination of certain pharmaceutical dosage forms containing the studied drugs

  17. A cylindrical furnace for absorption spectral studies

    Indian Academy of Sciences (India)

    R Venkatasubramanian

    2001-06-01

    A cylindrical furnace with three heating zones, capable of providing a temperature of 1100°C, has been fabricated to enable recording of absorption spectra of high temperature species. The temperature of the furnace can be controlled to ± 1°C of the set temperature. The salient feature of this furnace is that the material being heated can be prevented from depositing on the windows of the absorption cell by maintaining a higher temperature at both the ends of the absorption cell.

  18. A comparative study of ICH validated novel spectrophotometric techniques for resolving completely overlapping spectra of quaternary mixtures

    Science.gov (United States)

    Ali, Nouruddin W.; Abdelwahab, Nada S.; Abdelkawy, M.; Emam, Aml A.

    2016-02-01

    A pharmaceutically marketed mixture of Yohimbine, Alpha-tocopheryl acetate, Niacin, and Caffeine co-formulated as a promising therapy for erectile dysfunction. Simultaneous determination of the aforementioned pharmaceutical formulation without prior separation steps was applied using mean centering of ratio spectra and triple divisor spectrophotometric methods. Mean centering of ratio spectra method depended on using the mean centered ratio spectra in three successive steps which eliminated the derivative steps and so the signal to noise ratio was improved. The absorption spectra of the prepared solutions were measured in the wavelength range of 215-300 nm in the concentration ranges of 1-15, 3-15, 1-20, and 3-15 μg mL- 1 for Yohimbine, Alpha-tocopheryl acetate, Niacin, and Caffeine, respectively. The amplitudes of the mean centered third ratio spectra were measured at 250 nm and 268 nm for Yohimbine and Alpha-tocopheryl acetate, respectively and at peak to peak 272-273 and 262-263 nm for Niacin and Caffeine, respectively. In triple divisor method each drug in the quaternary mixture was determined by dividing the spectrum of the quaternary mixture by a standard spectrum of a mixture containing equal concentrations of the other three drugs. First derivative of these ratio spectra was obtained where determination could be achieved without any interference from the other three drugs. Amplitudes of 1-15, 3-15, 1-15, and 3-15 μg mL- 1 were used for selective determination of Yohimbine, Alpha-tocopheryl acetate, Niacin, and Caffeine, respectively. Laboratory prepared mixtures were analyzed by the developed novel methods to investigate their selectivity also, Super Act® capsules were successfully analyzed to ensure absence of interference from additives. The developed methods were validated according to the ICH guidelines. The proposed methods were statistically compared with each other and with the reported methods; using student t-test, F-test, and one way ANOVA

  19. Validated spectrophotometric methods for determination of some oral hypoglycemic drugs.

    Science.gov (United States)

    Farouk, M; Abdel-Satar, O; Abdel-Aziz, O; Shaaban, M

    2011-02-01

    Four accurate, precise, rapid, reproducible, and simple spectrophotometric methods were validated for determination of repaglinide (RPG), pioglitazone hydrochloride (PGL) and rosiglitazone maleate (RGL). The first two methods were based on the formation of a charge-transfer purple-colored complex of chloranilic acid with RPG and RGL with a molar absorptivity 1.23 × 103 and 8.67 × 102 l•mol-1•cm-1 and a Sandell's sensitivity of 0.367 and 0.412 μg•cm-2, respectively, and an ion-pair yellow-colored complex of bromophenol blue with RPG, PGL and RGL with molar absorptivity 8.86 × 103, 6.95 × 103, and 7.06 × 103 l•mol-1•cm-1, respectively, and a Sandell's sensitivity of 0.051 μg•cm-2 for all ion-pair complexes. The influence of different parameters on color formation was studied to determine optimum conditions for the visible spectrophotometric methods. The other spectrophotometric methods were adopted for demtermination of the studied drugs in the presence of their acid-, alkaline- and oxidative-degradates by computing derivative and pH-induced difference spectrophotometry, as stability-indicating techniques. All the proposed methods were validated according to the International Conference on Harmonization guidelines and successfully applied for determination of the studied drugs in pure form and in pharmaceutical preparations with good extraction recovery ranges between 98.7-101.4%, 98.2-101.3%, and 99.9-101.4% for RPG, PGL, and RGL, respectively. Results of relative standard deviations did not exceed 1.6%, indicating that the proposed methods having good repeatability and reproducibility. All the obtained results were statistically compared to the official method used for RPG analysis and the manufacturers methods used for PGL and RGL analysis, respectively, where no significant differences were found. PMID:22466095

  20. A transient absorption study of allophycocyanin

    Indian Academy of Sciences (India)

    Y J Shiu; J M Zhang; M Hayashi; V Gulbinas; C M Yang; S H Lin

    2002-12-01

    Transient dynamics of allophycocyanin trimers and monomers are observed by using the pump-probe, transient absorption technique. The origin of spectral components of the transient absorption spectra is discussed in terms of both kinetics and spectroscopy. We find that the energy gap between the ground and excited states of the unexcited subunit of allophycocyanin monomer decreases via an interaction with another excited subunit. For allophycocyanin trimer, we find that the fast dynamics results from the fast internal conversion and the first excited state is the only one electronic state which can trap the final population.

  1. Spectrophotometric Determination of Trimethylamine-nitrogen in Cadaver Tissues for the Estimation of Late Postmortem Interval: A Pilot Study

    Institute of Scientific and Technical Information of China (English)

    Qian LIU; Xiangyang CAI; Yan LIU; Lan ZHOU; Shaohua YI; Liang LIU

    2008-01-01

    To study the relationship between the late postmortem interval (PMI) and trimethylamine-nitrogen (TMA-N) in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different postmortem intervals (PMD by using a modified spectrophotometric method. The results indicated that the detection sensitivity of TMA-N was 1 mg/L, and there was a good linear correlation between the value of absorbance (A value) and TMA-N at the concentration of 1-10 mg/L (R2 =0.9991). Although TMA variation in muscles was different from that in inner organs during the time since death, TMA-N changes in cadaver tissues was positively correlated with PMI. During 2 to 7 d since death, the best correlation between PMI and TMA-N concentration was found in muscles.With PMI as an independent variable, the cubic polynomial regression equation was y= --0.457x3+6.519x2-24.574x+27.207 (R2=0.969). During 3 to 8 days since death, PMI was best correlated with TMA-N concentration in inner organs. With PMI as the independent variable, the cubic polynomial regression equation was y=0.509x3-9.153x2+55.727x-95.819 (R2=0.953). It was concluded that TMA-N in tissues could be used as a new estimator for late PMI. The method used in this study offered advantages such as accuracy, sensitivity, little samples required and wide PMI estimation.

  2. 石墨炉原子吸收分光光度法直接测定全血中锗%Graphite furnace atomic absorption spectrophotometric method for the direct determination of germanium in blood

    Institute of Scientific and Technical Information of China (English)

    高丽红

    2012-01-01

    Objective:To establish a graphite furnace atomic absorption spectrophotometric method for the determination of germanium in whole blood. Methods: Without treatment, germanium content in the sample was directly determined by graphite furnace atomic absorption spectrophotometry after sample dilution with 0. l%TritonX -100/ 0.2% HNO3 (v/v) as diluent and 0. 5 mg/ml calcium nitrate as matrix modifier. Results: The detection limit of the method (re = 10) was 0. 75 mg/L, the linearity was observed in the range of 0 μg/L ~ 190 μg/L, the relative standard deviation was 0. 8% ~ 3. 2% , the recovery rate was 99. 5% ~ 103. 6% . Conclusion: The method is simple, rapid with high recovery rate and precision, it is applicable to the determination of germanium content in whole blood.%目的:建立石墨炉原子吸收分光光度法测定全血中锗的方法.方法:样品无需处理,以0.1%TritonX-100/0.2% HNO3(v/v)为稀释液,以0.5 mg/ml硝酸钙为基体改进剂,对血液适当稀释后,直接用石墨炉原子吸收分光光度法测定锗的含量.结果:方法最低检出限(n=10)为0.75 mg/L,线性范围为0μg/L~190 μg/L,相对标准偏差0.8% ~3.2%,回收率为99.5% ~ 103.6%.结论:方法具有简便、快速、回收率高、精密度高的优点,适用于全血中锗含量的测定.

  3. Spectrophotometric Analysis of Caffeine

    Directory of Open Access Journals (Sweden)

    Showkat Ahmad Bhawani

    2015-01-01

    Full Text Available The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine.

  4. Pulse radiolysis and spectrophotometric studies on the binding of organic cations with heparin

    Science.gov (United States)

    Jakubowska, Małgorzata; Adamus, Jan; Gębicki, Jerzy; Marcinek, Andrzej; Sikora, Adam

    2014-06-01

    Here we present the spectroscopic and pulse radiolysis studies of the interactions of heparin and some organic cations:methylene blue (MB), 1-methylnicotinamide (MNA+), and its dimer 1,3-bis(1-methylnicotinamide)propane (bis(MNA+)).

  5. Comparative study of spectrophotometric methods manipulating ratio spectra: An application on pharmaceutical binary mixture of cinnarizine and dimenhydrinate

    Science.gov (United States)

    Lamie, Nesrine T.

    2015-04-01

    Four simple, specific, accurate and precise spectrophotometric methods are developed and validated for simultaneous determination of cinnarizine (CIN) and dimenhydrinate (DIM) in a binary mixture with overlapping spectra, without preliminary separation. The first method is dual wavelength spectrophotometry (DW), the second is a ratio difference spectrophotometric one (RD) which measures the difference in amplitudes between 250 and 270 nm of ratio spectrum, the third one is novel constant center spectrophotometric method (CC) and the fourth method is mean centering of ratio spectra (MCR). The calibration curve is linear over the concentration range of 4-20 and 10-45 μg/ml for CIN and DIM, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. The validity of results was assessed by applying standard addition technique. The results obtained were found to agree statistically with those obtained by a reported method, showing no significant difference with respect to accuracy and precision.

  6. The UV and IR Comparative Spectrophotometric Study of Some Saturated and Lacunary Polyoxometalates

    Directory of Open Access Journals (Sweden)

    Grama Lavinia

    2014-06-01

    Full Text Available Objectives: The polyoxometalates are a class of inorganic compounds with controllable shapes and sizes, and with excellent properties that make them attractive for various applications. This study is aimed at the comparative UV and IR spectra of Keggin type polyoxometalates.

  7. Spectrophotometric study into complexing of vanadium(3) with salicylic acid derivatives

    International Nuclear Information System (INIS)

    Complexing of vanadium (3) with 5 amino-salicylic acid and amide of salicylhydroxamic acid has been studied. It has been shown that in acidic medium V3+ forms yellow complexes of the composition 1:1 with instability constants 2.2x10-19, 7.8x10-11, and 2.2x10-12, respectively. Complexes of V3+ with derivatives of salicylic acid can be used for determining V(3) content in the presence of V(4)

  8. Kinetic Spectrophotometric Determination of Certain Cephalosporins in Pharmaceutical Formulations

    OpenAIRE

    Omar, Mahmoud A.; Osama H. Abdelmageed; Tamer Z. Attia

    2009-01-01

    A simple, reliable, and sensitive kinetic spectrophotometric method was developed for determination of eight cephalosporin antibiotics, namely, Cefotaxime sodium, Cephapirin sodium, Cephradine dihydrate, Cephalexin monohydrate, Ceftazidime pentahydrate, Cefazoline sodium, Ceftriaxone sodium, and Cefuroxime sodium. The method depends on oxidation of each of studied drugs with alkaline potassium permanganate. The reaction is followed spectrophotometrically by measuring the rate of change of abs...

  9. Determination of Tapentadol Hydrochloride in Tablets by Three New Validated Spectrophotometric Methods

    Directory of Open Access Journals (Sweden)

    Deepti Jain

    2013-12-01

    Full Text Available Three UV spectrophotometric methods viz. linear regression equation (LRE, standard absorptivity (SA and first order derivative (FOD method were developed and validated according to ICH guideline. The methods were linear in the range of 10-50 μg/mL and validated methods were successfully applied for determination of tapentadol hydrochloride content in tablet dosage forms in the range of 100.42-100.64%, 100.31-100.54% and 100.10-100.59%, respectively. The standard deviation for all the methods was found to be less than one unit (0.45-0.83. The validated spectrophotometric methods may be successfully applied for assay, dissolution studies, bio-equivalence studies as well as routine analysis in pharmaceutical industries.

  10. Spectrophotometric study of the anodic corrosion of Ti/RuO{sub 2} electrode in acid sulfate solution

    Energy Technology Data Exchange (ETDEWEB)

    Gajic-Krstajic, Lj.M.; Trisovic, T.Lj.; Krstajic, N.V

    2004-01-01

    Electrochemical properties of RuO{sub 2}-based electrode, particularly the oxygen evolution and anodic dissolution of RuO{sub 2} have been investigated in 0.5 mol dm{sup -3} H{sub 2}SO{sub 4} solution by means of polarization measurements and product analysis. It has been demonstrated that it is possible to determine very low concentration of dissolved ruthenium species (8 x 10{sup -10} mol dm{sup -3} Ru) by a sensitive spectrophotometric method based on the ruthenium-catalyzed ceric-arsenite reaction. Finally, the probable mechanism of anodic dissolution of RuO{sub 2}-based electrode, has been proposed.

  11. Derivative spectrophotometric determination of uranium (VI using diacetyl monoxime isonicotinoyl hydrazone (DMIH

    Directory of Open Access Journals (Sweden)

    ChandraSekhar Reddy Gadikota

    2011-08-01

    Full Text Available Uranium (VI forms a yellow coloured water soluble complex with diacetyl monoxime isonicotinoyl hydrazone (DMIH reagent in acidic buffer of pH 3.25 with ?max at 364 nm. The molar absorptivity and sandell’s sensitivity are 1.63 X 10 4 L.mol -1.cm-1 and 0.00307692 µg/cm 2, respectively. The Beer’s law validity range is 1.19–14.28 µg/mL. Uranium (VI forms (M:L 1:1 complex with DMIH and stability constant of the complex is 4.928 X 106 .The derivative spectrophotometric determination of U (VI was carried out by measuring peak height method. The developed derivative spectrophotometric method was employed for the determination of uranium (VI in rock and synthetic samples. The effect of various diverse ions was also studied.

  12. Microwave absorption studies of MgB2 superconductor

    Indian Academy of Sciences (India)

    M K Bhide; R M Kadam; M D Sastry; Ajay Singh; Shashwati Sen; Manmeet Kaur; D K Aswal; S K Gupta; V C Sahni

    2002-05-01

    Microwave absorption studies have been carried out on MgB2 superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for polycrystalline (grain size ∼ 10m) samples suggested the absence of weak-link character. The field dependent direct microwave absorption has been found to obey a $\\sqrt{H}$ dependence with two different slopes, which indicated a transition from strongly pinned lattice to flux flow regime.

  13. Radiant energy absorption studies for laser propulsion. [gas dynamics

    Science.gov (United States)

    Caledonia, G. E.; Wu, P. K. S.; Pirri, A. N.

    1975-01-01

    A study of the energy absorption mechanisms and fluid dynamic considerations for efficient conversion of high power laser radiation into a high velocity flow is presented. The objectives of the study are: (1) to determine the most effective absorption mechanisms for converting laser radiation into translational energy, and (2) to examine the requirements for transfer of the absorbed energy into a steady flow which is stable to disturbances in the absorption zone. A review of inverse Bremsstrahlung, molecular and particulate absorption mechanisms is considered and the steady flow and stability considerations for conversion of the laser power to a high velocity flow in a nozzle configuration is calculated. A quasi-one-dimensional flow through a nozzle was formulated under the assumptions of perfect gas.

  14. Method development, validation and stability study of ritonavir in bulk and pharmaceutical dosage form by spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Anindita Behera

    2011-01-01

    Full Text Available Background: Ritonavir is a protease inhibitor and mostly used as a booster for increasing the bioavailability of other protease inhibitors like Atazanavir Sulfate and Lopinavir. Aims: Quality assessment of the new dosage form of Ritonavir i.e. tablets is very essential, so two sensitive, simple and precise methods are developed for quantification of Ritonavir in bulk and tablet dosage forms. Materials and Methods: The first method is based on first order derivative method and the second is based on area under curve method. Both the methods are validated according to international conference of harmonization (ICH guidelines. A stability study of Ritonavir is done in UV - Visible Spectrophotometer under different stress conditions recommended by ICH guidelines. Results: The absorption maximum is found to be 239nm in methanol. The absorption maximum in first method is chosen at 253.2nm, and the linearity is found between 4 - 20 ΅g/ml with coefficient of correlation value 0.9981. In the second method, the range for area under curve selected is 237 - 242nm. The linearity is found between 4 -20 ΅g/ml with coefficient of correlation value 0.9992. Conclusion: The developed methods are validated and found to be simple, rapid, precise and cost-effective. The degradation study in tablet dosage form can be used as a stability indicating assay method.

  15. Transient absorption microscopy studies of single metal and semiconductor nanostructures

    Science.gov (United States)

    Johns, Paul; Sajini-Devadas, Mary; Hartland, Gregory V.

    2015-08-01

    Transient absorption microscopy is an experimental technique that allows nanomaterials to be studied with ultrafast time resolution and diffraction limited spatial resolution. This paper describes recent results from using transient absorption microscopy to investigate energy relaxation processes in single metal and semiconductor nanowires. The processes that have been examined include charge carrier trapping in semiconductor nanostructures, the motion of surface plasmon polaritons in metal nanowires, and the damping of the acoustic breathing modes of metal nanowires by high viscosity solvents.

  16. Absorptive capacity in European manufacturing: a Delphi study

    OpenAIRE

    Jung Erceg, Petra; Pandža, Krsto; Armbruster, Heidi; Dreher, Carsten

    2012-01-01

    This paper sets out to discuss the results of a specific part of a Europe-wide Delphi study that considers issues of absorptive capacity in European manufacturing. Owing to the importance to competitiveness of increasing innovative capabilities in manufacturing it is highly relevant to explore how a wide community of manufacturing experts experience the phenomenon of absorptive capacity and sense future developments. A two round Delphi method was designed in which more than 3,000 experts from...

  17. Absorption heat cycles. An experimental and theoretical study

    International Nuclear Information System (INIS)

    A flow sheeting programme, SHPUMP, was developed for simulating different absorption heat cycles. The programme consists of ten different modules which allow the user to construct his own absorption cycle. The ten modules configurate evaporators, absorbers, generators, rectifiers, condensers, solution heat exchangers, pumps, valves, mixers and splitters. Seven basic and well established absorption cycles are available in the configuration data base of the programme. A new Carnot model is proposed heat cycles. Together with exergy analysis, general equations for the Carnot coefficient of performance and equations for thermodynamic efficiency, exergetic efficiency and exergy index, are derived, discussed and compared for both absorption heat pumps and absorption heat transformers. Utilizing SHPUMP, simulation results are presented for different configurations where absorption heat cycles are suggested to be incorporated in three different unit operations within both pulp and paper and oleochemical industries. One of the application studies reveled that an absorption heat transformer incorporated with an evaporation plant in a major pulp and paper industry, would save 18% of the total prime energy consumption in one of the evaporation plants. It was also concluded that installing an absorption heat pump in a paper drying plant would result in steam savings equivalent to 12 MW. An experimental absorption heat transformer unit operating with self-circulation has been modified and thoroughly tested. A reference heat transformer plant has been designed and installed in a major pulp and paper mill where it is directly incorporated with one of the evaporation plants. Preliminary plant operation data are presented. 72 refs, 63 figs, 33 tabs

  18. A New Way to Study Water-Vapor Absorption Coefficient

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In the visible spectrum, the atmospheric attenuations to sunlight mainly include aerosol scattering, atmospheric molecule Rayleigh scattering and ozone absorption, while in the near-infrared spectrum (from 650 nm to 1000 nm), we must take water-vapor absorption into account. Based on the atmospheric correction theory, using spectrum irradiance data measured by Instantaneous Ground spectrometer, ozone content measured by Microtops Ⅱ ozone monitor,water-vapor content and aerosol optical thickness measured by sun photometer, we give a new way to study water-vapor absorption to sunlight, and the result shows that the main peak values of water-vapor absorption coefficients are 0.025 cm-1, 0.073 cm-1, 0.124 cm-1, 0.090 cm-1, 0.141cm-1 and 0.417 cm-1, which respectively lie at 692 nm, 725 nm, 761 nm, 818 nm, 912 nm and 937 nm.

  19. Plutonium spectrophotometric analysis

    International Nuclear Information System (INIS)

    Plutonium ions in solution have absorption spectra so different that it is possible to use them for analytical purposes. Detailed studies have been performed in nitric solutions. Some very convenient methods for the determination of plutonium and its oxidation states, especially the ratios Pu(III):Pu(IV) and Pu(IV):Pu(VI) in a mixture of both, have been developed. These methods are described in this paper, including: a) Absorption spectra for plutonium (III), (IV), (VI) and mixtures. b) Relative extinction coefficients for the above mentioned species. c) Dependences of the relative extinction coefficients on the nitric acid concentration and the plutonium VI deviation from the Beer-Lambert law. The developed methods are simple and rapid and then, suitable in process control. Accuracy is improved when relative absorbance measurements are performed or controlled the variables which have effect on the spectra and extinction coefficients. (Author)

  20. A spectrophotometric study of the protonation processes of some N-[1-(benzimidazol-1-yl]methylbenzamide derivatives

    Directory of Open Access Journals (Sweden)

    NADA U. PERISIC-JANJIC

    2000-01-01

    Full Text Available The protonation of N-[1-(benzimidazol-1-yl]methylbenzamide derivatives in aqueous acids (H2SO4 media was investigated, using a spectrophotometric method. The investigated compounds have two protonation processes. The first protonation process occurs in weakly acidic aqueous solutions (pH range and refers to the protonation of the benzimidazole part of the molecule. The second protonation process occurs in concentrated sulfuric acid solutions and refers to protonation of the amide group. The protonation constants of the second process were calculated by the Hammett and Cox-Yates method. The effect of chemical structure on the ionisation constants is discussed. A correlation between the protonation constants and antimicrobial activity was established.

  1. Spectrophotometric and Calorimetric Studies of Np(V) Complexation with Sulfate at 10-70oC

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Linfeng; Tian, Guoxin; Xia, Yuanxian; Friese, Judah I.

    2008-06-16

    Sulfate, one of the inorganic constituents in the groundwater of nuclear waste repository, could affect the migration of radioactive materials by forming complexes. Spectrophotometric and microcalorimetric titrations were performed to identify the Np(V)/sulfate complex and determine the equilibrium constants and enthalpy of complexation at 10-70 C. Results show that the complexation of Np(V) with sulfate is weak but slightly enhanced by the increase in temperature. The complexation is endothermic and becomes more endothermic with the increase in temperature. The enhanced complexation at elevated temperatures is due to the increasingly larger entropy of complexation that exceeds the increase in enthalpy, suggesting that the complexation of Np(V) with sulfate is entropy-driven.

  2. Spectrophotometric and Calorimetric Studies of Np(V) Complexation with Acetate at Variable Temperatures (T = 283 - 343 K)

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Linfeng; Tian, Guoxin; Srinivasan, Thandankorai G.; Zanonato, PierLuigi; Di Bernardo, Plinio

    2009-12-21

    Spectrophotometric titrations were performed to identify the Np(V)/acetate complex and determine the equilibrium constants at variable temperatures (T = 283 - 343 K) and at the ionic strength of 1.05 mol {center_dot} kg{sup -1}. The enthalpy of complexation at corresponding temperatures was determined by microcalorimetric titrations. Results show that the complexation of Np(V) with acetate is weak but strengthened as the temperature is increased. The complexation is endothermic and is entropy-driven. The enhancement of the complexation at elevated temperatures is primarily due to the increasingly larger entropy gain when the solvent molecules are released from the highly-ordered solvation spheres of NpO{sub 2}{sup +} and acetate to the bulk solvent where the degree of disorder is higher at higher temperatures.

  3. Mechanistic chemistry of oxidation of balsalazide with acidic chloramine-T and bromamine-T: A comparative spectrophotometric kinetic study

    Indian Academy of Sciences (India)

    Puttaswamy; S Dakshayani

    2014-11-01

    Balsalazide (BSZ) belongs to a class of non-steroidal anti-inflammatory drugs. Kinetics and mechanism of oxidation of BSZ with sodium N-halo-p-toluenesulfonamides viz., chloramine-T(CAT) and bromamine-T(BAT) in HClO4 medium have been spectrophotometrically investigated (max =357nm) at 303 K. Under comparable experimental conditions, reactions with both the oxidants follow a first-order dependence of rate on [BSZ] and fractional-order dependence on each [oxidant] and [HClO4]. Activation parameters and reaction constants have been computed. 2-hydroxy-5-nitroso-benzoic acid and 3-(4-nitroso-benzoylamino)-propionic acid are identified as the oxidation products of BSZ with both CAT and BAT. The rate of oxidation of BSZ is about five-fold faster with BAT than with CAT. Plausible mechanism and related rate law have been deduced for the observed kinetics.

  4. Aqueous complexation of citrate with neodymium(III) and americium(III): a study by potentiometry, absorption spectrophotometry, microcalorimetry, and XAFS.

    Science.gov (United States)

    Brown, M Alex; Kropf, A Jeremy; Paulenova, Alena; Gelis, Artem V

    2014-05-01

    The aqueous complexation of Nd(III) and Am(III) with anions of citrate was studied by potentiometry, absorption spectrophotometry, microcalorimetry, and X-ray absorption fine structure (XAFS). Using potentiometric titration data fitting the metal-ligand (L) complexes that were identified for Nd(III) were NdHL, NdL, NdHL2, and NdL2; a review of trivalent metal-citrate complexes is also included. Stability constants for these complexes were calculated from potentiometric and spectrophotometric titrations. Microcalorimetric results concluded that the entropy term of complex formation is much more dominant than the enthalpy. XAFS results showed a dependence in the Debye-Waller factor that indicated Nd(iii)-citrate complexation over the pH range of 1.56-6.12.

  5. Spectrophotometric estimation of risperidone in tablets

    OpenAIRE

    B. K. Jayanna; Devaraj, T. D.; Roopa, K. P.; G. Nagendrappa; H R Arun Kumar; Gowda, N.

    2014-01-01

    A simple, rapid and highly sensitive spectrophotometric method is developed for the determination of risperidone in tablet formulation. The method is based on the oxidation of drug using potassium permanganate in alkaline medium and excess potassium permanganate oxidizes 1,10-phenanthroline Fe(II). The measurement of decrease in absorbance of 1,10-phenanthroline Fe (II) was done at 415 nm. The beer′s law is obeyed in the concentration range of 5.0 to 40.0 μg/ml and molar absorptivity is found...

  6. Simultaneous spectrophotometric determination of drotaverine hydrochloride and paracetamol in tablet

    Directory of Open Access Journals (Sweden)

    Mahaparale Sonali

    2010-01-01

    Full Text Available Two simple, accurate and reproducible spectrophotometric methods; Q analysis and first order derivative method have been described for the simultaneous estimation of drotaverine hydrochloride and paracetamol in combined tablet dosage form. Absorption maxima of drotaverine hydrochloride and paracetamol in distilled water were found to be 303.5 nm and 243.5 nm respectively. Beer′s law was obeyed in the concentration range 5-50 µg/ml for drotaverine and 5-60 µg/ml for paracetamol. In Q analysis method, two wavelengths were selected at isobestic point (277 nm and λmax of paracetamol (243.5 nm. In first order derivative method, zero crossing point for drotaverine hydrochloride and paracetamol were selected at 303.5 nm and 243.5 nm, respectively. The results of two methods were validated statistically and recovery studies were found to be satisfactory.

  7. [Spectrophotometric determination of cinnarizine based on charge-transfer reaction].

    Science.gov (United States)

    Xu, B; Zhao, F; Tong, S

    1999-12-01

    The charge-transfer (CT) complex formed between cinnarizine as the donor and 7, 7, 8, 8-Tetracyanoquinodimethane (TCNQ) as the acceptor in acetone-methanol has been studied by spectrophotometric method. Beer's law is obeyed in the range of 0-18 microg x mL(-1) of cinnarizine. The apparent molar absorptivity of CT complex at 743 nm is 1.58 x 10(4) L x mol(-1) x cm(-1). The composition of CT complex is found to be 1 : 1 by Bent-French and Job's methods. The relative standard deviation is less than 3% (n = 10). The method has been applied to the determination of cinnarizine in tablets with satisfactory results. PMID:15822327

  8. Spectrophotometric intracutaneous analysis versus dermoscopy for the diagnosis of pigmented skin lesions: prospective, double-blind study in a secondary reference centre

    DEFF Research Database (Denmark)

    Glud, Martin; Gniadecki, Robert; Drzewiecki, Krzysztof T

    2009-01-01

    . Spectrophotometric intracutaneous analysis (SIAscopy) is a new, commercially available method of analyzing pigmented skin lesions noninvasively. The diagnosis is based on objective features such as the presence of dermal pigment, vascularity of the lesion, and the integrity of collagen. The objective of this study......Dermoscopy is considered to be the golden standard for the clinical assessment of pigmented skin lesions. In expert hands, this instrument improves both sensitivity and specificity for the diagnosis of melanoma, however, the outcome is highly dependent on the skills and experience of the examiner....... The specificity of dermoscopy in this study was 81% against 59% for SIAscopy. Our result shows that dermoscopy remains the best diagnostic tool for the preoperative diagnosis of pigmented skin lesions. However, as the SIAscope in addition to the SIAgraph images produces dermoscopic images, it holds the advantages...

  9. Spectrophotometric Determination of Ezetimibe

    OpenAIRE

    P. Baby Sudha Lakshmi; Ramchandran, D.; Rambabu, C.

    2010-01-01

    Two simple, sensitive, selective and accurate spectro-photometric methods (Method A and Method B) for the determination of eztimibe in bulk drug and pharmaceutical formulations (tablets) have been described. Method A and B are based on the redox/complex formation reaction of drug with 1,10-phenanthroline and hexacyano-ferrate(III) in presence of ferric chloride to form coloured chromogens exhibiting λmax at 510 and 740 nm respectively. The results of analysis for the two methods have been val...

  10. Percutaneous absorption of methimazole: an in vitro study of the absorption pharmacokinetics for two different vehicles.

    Science.gov (United States)

    Hill, K E; Mills, P C; Jones, B R; Bolwell, C F; Aberdein, D; Chambers, J P

    2015-12-01

    The use of transdermal medications in cats has become popular in veterinary medicine due to the ease of administration compared to oral medication. However, the research to support systemic absorption of drugs applied to the pinna after transdermal administration in cats is limited. The aim of this study was to characterize the percutaneous absorption pharmacokinetics of methimazole in a lipophilic vehicle compared to methimazole in Pluronic(®) lecithin organogel (PLO) using a finite dose applied to feline ear skin in an in vitro Franz cell model. The two formulations of methimazole (10 mg) were applied to the inner stratum corneum of six pairs of feline ears. The receptor medium was sampled up to 30 h post-administration, and methimazole concentrations were measured using high-performance liquid chromatography (HPLC). Histological examination of all ears was undertaken as small differences in the thickness of ear skin may have contributed to inter-individual differences in methimazole absorption between six cats. Methimazole was absorbed more completely across the pinnal skin when administered in the lipophilic vehicle compared to administration in the PLO gel (P < 0.001).

  11. Spectrophotometric Procedure for Fast Reactor Advanced Coolant Manufacture Control

    Science.gov (United States)

    Andrienko, O. S.; Egorov, N. B.; Zherin, I. I.; Indyk, D. V.

    2016-01-01

    The paper describes a spectrophotometric procedure for fast reactor advanced coolant manufacture control. The molar absorption coefficient of dimethyllead dibromide with dithizone was defined as equal to 68864 ± 795 l·mole-1·cm-1, limit of detection as equal to 0.583 · 10-6 g/ml. The spectrophotometric procedure application range was found to be equal to 37.88 - 196.3 g. of dimethyllead dibromide in the sample. The procedure was used within the framework of the development of the method of synthesis of the advanced coolant for fast reactors.

  12. Spectrophotometric and conductometric study of the complexation of N-salicylidene-2-aminophenol with Cu2+ in methanol + 1,4-dioxane binary solutions

    Directory of Open Access Journals (Sweden)

    Biswas Rashmidipta

    2014-01-01

    Full Text Available The complexation reaction between N-salicylidene-2-aminophenol, abbreviated as SAP, with Cu2+ ion was studied in binary mixtures of methanol and 1,4-dioxane by using conductometric and spectrophotometric method at different temperatures. The stability constants (Kf for the 1:1 complex, Cu2+-SAP, were calculated from computer fitting of absorbance and molar conductance data against various mole ratios (cM:cL or cL:cM in different binary solvent mixtures. A non-linear behaviour was observed for the variation of logKf for the complex against the solvent compositions. Various thermodynamic parameters (ΔH, ΔS and ΔG for the formation of Cu2+-SAP complex were determined from the temperature dependence of stability constants (Kf. The overall results showed that the complexation reaction is entropy driven and is affected by the nature and composition of the mixed solvents.

  13. Comparative study of solvent properties for carbon dioxide absorption

    Energy Technology Data Exchange (ETDEWEB)

    Aschenbrenner, O.; Styring, P. [University of Sheffield, Sheffield (United Kingdom)

    2010-07-01

    Several inexpensive and non-toxic solvents with low vapour pressures were investigated for their suitability as alternative solvents for the absorption of carbon dioxide from flue gas. The solvents include poly(ethylene glycol)s, poly(ethylene glycol) ethers, poly(ethylenimine) and glycerol-based substances. Solvent properties such as thermal stability, solubility of carbon dioxide and selectivity over nitrogen were investigated in a systematic study using a thermogravimetric analyser. Absorption results are reported for pure carbon dioxide and nitrogen as well as a mixture of both gases. Desorption and long-term sorption behaviour are also discussed. Glycerol and poly(ethylene glycol)s show a high solubility of carbon dioxide. Due to the high viscosity of the solvent, carbon dioxide absorption in poly(ethylenimine) is very slow in spite of the presence of favourable amine groups. PEG 300 was found to be the best solvent in this study and shows a high carbon dioxide solubility as well as good selectivity over nitrogen. The advantages of high stability, low solvent loss and low desorption energy of PEG 300 may outweigh its lower absorption capacity compared to the state-of-the-art solvent monoethanolamine, making it a potentially advantageous solvent for industrial carbon dioxide absorption processes.

  14. Study on optical weak absorption of borate crystals

    Science.gov (United States)

    Li, Xiaomao; Hu, Zhanggui; Yue, Yinchao; Yu, Xuesong; Lin, Zheshuai; Zhang, Guochun

    2013-10-01

    Borate crystal is an important type of nonlinear optical crystals used in frequency conversion in all-solid-state lasers. Especially, LiB3O5 (LBO), CsB3O5 (CBO) and CsLiB6O10 (CLBO) are the most advanced. Although these borate crystals are all constructed by the same anionic group-(B3O7)5-, they show different nonlinear optical properties. In this study, bulk weak absorption values of three borate crystals have been studied at 1064 nm by a photothermal common-path interferometer. The bulk weak absorption values of them along [1 0 0], [0 1 0] and [0 0 1] directions were obtained, respectively, to be approximately 17.5 ppm cm-1, 15 ppm cm-1 and 20 ppm cm-1 (LBO); 80 ppm cm-1, 100 ppm cm-1 and 40 ppm cm-1 (CBO); 600 ppm cm-1, 600 ppm cm-1 and 150 ppm cm-1 (CLBO) at 1064 nm. The results showed an obvious discrepancy of the values of these crystals along three axis directions. A correlation between the bulk weak absorption property and crystal intrinsic structure was then discussed. It is found that the bulk weak absorption values strongly depend on the interstitial area surrounded by the B-O frames. The interstitial area is larger, the bulk weak absorption value is higher.

  15. Theoretical Study on Sulfur Dioxide Absorption with Citrate Solution

    Institute of Scientific and Technical Information of China (English)

    薛娟琴; 洪涛; 王召启; 李林波

    2006-01-01

    The citrate absorption of SO2 is currently one of the most successful and economic methods to harness sulfur dioxide pollution.In order to theoretically elucidate the mechanism of SO2 absorption by citrate solution and provide theoretical instruction for experiments and industrial process, the theory of multi-buffer solution, combined with computer numerical calculation methods, was applied to study the distribution parameters of the components of the citrate solution in the process of SO2 absorption and the following results were obtained: (1) HCi2- and H2Ci- in the citrate solution played the dominant role in the absorption and desorption processes; (2) Through the calculation for the buffer capacity of citrate solution, it was found that the pH of the absorption and desorption solution should be in the range of 2~8, while at pH=4.5 the buffer capacity reached its maximum. Some valuable parameters were obtained, which are instructive to the ensuing experiments and industrial design.

  16. Study on Optical Absorption Behavior of Dyestuff in Fabric

    Institute of Scientific and Technical Information of China (English)

    YANG Hong-ying; ZHU Su-kang; ZUO Lei; ZHU Ping-ping; PAN Ning

    2008-01-01

    Fabric is a kind of turbid materials with strong light scattering,to which the Kubelka-Munk theory can be applied to describe it optical behavior.In this paper,the light absorption coefficients of dyestuff in fabrics are obtained by test and calculation thnmgh a special method proposed by the authors.Then the optical behaviours of dyestuff in fabric are studied.Results show that,the absorption coeffident of dye in fabric is non-scalable and exponential to dye concentrafion in fabric which is totally different from that of the dye in transparent medm like water.

  17. Chemical relevance of the copper(II)— L-carnosine system in aqueous solution: A thermodynamic and spectrophotometric study

    Science.gov (United States)

    Daniele, Pier G.; Prenesti, Enrico; Zelano, Vincenzo; Ostacoli, Giorgio

    1993-08-01

    The copper(II)— L-carnosine (L -) system has been re-investigated in aqueous solution, at I = 0.1 mol dm -1, different temperatures (5⩽ t⩽45°C) and with metal to ligand ratios ranging from 3:1 to 1:3. Both potentiometry and visible spectrophotometry were employed. From an overall consideration of all experiments, [CuLH] 2+, [CuL] +, [CuLH -1]°, [Cu 2L 2H -2]° and [Cu 2LH -1] 2+ were recognized as the species which provide the best interpretation of experimental data. The complex formation constants, determined at different temperatures, allowed us to obtain reliable values of Δ H° and good estimates of Δ C° p. From visible spectrophotometric measurements, carried out at different pH and metal to ligand ratios, it was possible to calculate the electronic spectrum of each complex formed in solution. A structure is also proposed for each species, on the basis of thermodynamic and spectral results.

  18. Spectrophotometric and Calorimetric Studies of U(VI) Complexation with Sulfate at 25-70oC

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Guoxin; Rao, Linfeng

    2008-10-30

    Sulfate, one of the inorganic constituents in the groundwater of nuclear waste repository, could affect the migration of radioactive materials by forming complexes. Spectrophotometric and microcalorimetric titrations were performed to identify the U(VI)/sulfate complexes and determine the equilibrium constants and enthalpy of complexation at 25-70 C. Results show that U(VI) forms moderately strong complexes with sulfate, i.e., UO{sub 2}SO{sub 4}(aq) and UO{sub 2}(SO{sub 4}){sub 2}{sup 2-}, in this temperature range and the complexes become stronger as the temperature is increased: 2-fold and 10-fold increases in the stability constants of UO{sub 2}SO{sub 4}(aq) and UO{sub 2}(SO{sub 4}{sub 2}{sup 2-}), respectively, when the temperature is increased from 25 C to 70 C. The complexation is endothermic and entropy-driven, showing typical characteristics of inner-sphere complexation and 'hard acid'/'hard base' interactions. The thermodynamic trends are discussed in terms of dehydration of both the cation (UO{sub 2}{sup 2+}) and the anion (SO{sub 4}{sup 2-}) as well as the effect of temperature on the structure of water.

  19. Effects of Omeprazole on Iron Absorption: Preliminary Study

    Directory of Open Access Journals (Sweden)

    Mahmut Yaşar Çeliker

    2013-09-01

    Full Text Available Objective: Increasing numbers of pediatric and adult patients are being treated with proton pump inhibitors (PPIs. PPIs are known to inhibit gastric acid secretion. Nonheme iron requires gastric acid for conversion to the ferrous form for absorption. Ninety percent of dietary and 100% of oral iron therapy is in the nonheme form. To the best of our knowledge, the effect of PPIs on iron absorption has not been studied in humans. Our study assessed the relationship between omeprazole therapy and iron absorption in healthy subjects. Materials and Methods: We recruited 9 healthy volunteers between June 2010 and March 2011. Subjects with chronic illness, anemia, or use of PPI therapy were excluded. Serum iron concentrations were measured 1, 2, and 3 h after the ingestion of iron (control group. The measurements were repeated on a subsequent visit after 4 daily oral administrations of omeprazole at a dose of 40 mg (treatment group. Results: One female and 8 male volunteers were enrolled in the study with a mean age of 33 years. There was no statistical difference detected between baseline, 1-h, 2-h, and 3-h iron levels between control and treatment groups. Conclusion: Administration of omeprazole for a short duration does not affect absorption of orally administered iron in healthy individuals.

  20. Radioisotope studies for quantitative measurement of manganese absorption

    International Nuclear Information System (INIS)

    Purpose of the present study was to quantitatively determine the manganese absorption in growing rats by means of radioisotopes. First of all the following factors had to be investigated, which are significant for this determination: Measurability of stable and radioactive Mn in rat tissues; labelling of stable Mn and distribution of stable and radioactive Mn in the organism; verification of the isotope dilution method and of the comparative balance method with regard to its applicability for the determination of the true Mn absorption. We useed male and female Sprague-Dawley rats. The most important results are summarized in the following: in some separate tissues measurement of stable Mn was accompanied by difficulties. The measurement of radioactive Mn however, could be performed without any problems. 10 d after i.m. injection of 54Mn only 17% of the administered Mn was still detectable in the organism. However, there was no uniform tissue labelling found. Therefore it is possible to an only restricted extent to draw quantitative conclusions on the content of stable Mn. A high percentage of stable and radioactive Mn was found above all in the liver. The isotope dilution method permits by feces analysis to differentiate between unabsorbed Mn coming from the food and endogenic Mn coming from the organism itself. The effective Mn absorption was also determined by means of the comparative balance method. By means of the isotope dilution method we determined the quantitative Mn-absorption with staged Mn administration and the contribution of absorption and excretion to the homeostatic regulation mechanisms of Mn. We found that absorption and excretion help the organism to keep an almost constant Mn concentration even with a differing Mn supply. (orig./MG)

  1. Artificial neural networks study of the catalytic reduction of resazurin: stopped-flow injection kinetic-spectrophotometric determination of Cu(II) and Ni(II)

    Energy Technology Data Exchange (ETDEWEB)

    Magni, Diana M. [Departamento de Quimica, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina); Olivieri, Alejandro C. [Departamento de Quimica Analitica, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario (Argentina); Bonivardi, Adrian L. [Departamento de Quimica, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina) and Instituto de Desarrollo Tecnologico para la Industria Quimica, Gueemes 3450, S3000GLN Santa Fe (Argentina)]. E-mail: bonivar@fiqus.unl.edu.ar

    2005-01-10

    An artificial neural network (ANN) procedure was used in the development of a catalytic spectrophotometric method for the determination of Cu(II) and Ni(II) employing a stopped-flow injection system. The method is based on the catalytic action of these ions on the reduction of resazurin by sulfide. ANNs trained by back-propagation of errors allowed us to model the systems in a concentration range of 0.5-6 and 1-15 mg l{sup -1} for Cu(II) and Ni(II), respectively, with a low relative error of prediction (REP) for each cation: REP{sub Cu(II)} = 0.85% and REP{sub Ni(II)} = 0.79%. The standard deviations of the repeatability (s{sub r}) and of the within-laboratory reproducibility (s{sub w}) were measured using standard solutions of Cu(II) and Ni(II) equal to 2.75 and 3.5 mg l{sup -1}, respectively: s{sub r}[Cu(II)] = 0.039 mg l{sup -1}, s{sub r}[Ni(II)] = 0.044 mg l{sup -1}, s{sub w}[Ni(II)] = 0.045 mg l{sup -1} and s{sub w}[Ni(II)] = 0.050 mg l{sup -1}. The ANNs-kinetic method has been applied to the determination of Cu(II) and Ni(II) in electroplating solutions and provided satisfactory results as compared with flame atomic absorption spectrophotometry method. The effect of resazurin, NaOH and Na{sub 2}S concentrations and the reaction temperature on the analytical sensitivity is discussed.

  2. Intestinal perfusion in the study of intestinal absorption

    International Nuclear Information System (INIS)

    Several techniques for studying absorption by means of intestinal perfusion have been developed. While the principle is simple, the practice is complicated by absorption of the solvent and by excretion of fluid into the lumen. To improve reliability a ''marker'' is incorporated into the system; it should behave as nearly as possible like the nutrient of interest, except that it should be unabsorbable. A great many markers, including several labelled with radionuclides, have been developed for use with numerous nutrients, and perfusion methods using double or triple tubes or occlusive balloons have been tested. The perfusion technique is too complicated for routine diagnostic use, but it offers at present the only possibility of studying the function of defined sections of the small intestine in the intact human. (author)

  3. A New Spectrophotometric Method for Measuring COD of Seawater

    Institute of Scientific and Technical Information of China (English)

    LIU Ying; JI Hongwei; XIN Huizhen; LIU Li

    2006-01-01

    This research studied a new spectrophotometric method for measuring the chemical oxygen demand (COD) of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thiosulphate.The measuring wavelength was selected to be 470 nm, and the COD of three standard glucose solutions (COD = 0.5, 1.5 and2.5 mgL-1, respectively) and two seawater samples (from the South Yellow Sea and Jiaozhou Bay) were measured using the spectrophotometric method and titrimetric method respectively. The results showed that the spectrophotometric method was somewhat better than the titrimetric method. The relative standard deviation (RSD) of the spectrophotometric method was less than 2.7%, and the recovery of seawater samples ranged from 96.3% to 103.8%. In addition, the spectrophotometric method has other advantages such as expeditiousness, operation simplicity, analysis automatization, etc. Therefore the spectrophotometric method can be used to measure the COD of seawater with satisfactory results.

  4. Spectroscopic study of low-temperature hydrogen absorption in palladium

    Energy Technology Data Exchange (ETDEWEB)

    Ienaga, K., E-mail: ienaga@issp.u-tokyo.ac.jp; Takata, H.; Onishi, Y.; Inagaki, Y.; Kawae, T. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Motooka, Nishi-Ku, Fukuoka 819-0395 (Japan); Tsujii, H. [Department of Physics, Faculty of Education, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Kimura, T. [Department of Physics, Kyushu University, Hakozaki, Higashi-Ku, Fukuoka 812-8581 (Japan)

    2015-01-12

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H{sub 2} using inelastic electron spectroscopy (IES). After introduction of liquid H{sub 2}, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ∼ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

  5. $\\beta$-decay studies using total-absorption spectroscopy

    CERN Document Server

    Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Kirchner, R; Karny, M; Le Scornet, G; Miehé, C; Maréchal, F; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Taín, J L; Tengblad, O; Wittmann, V

    2004-01-01

    $\\beta$-decay experiments are a primary source of information for nuclear-structure studies and at the same time complementary to in- beam investigations of nuclei far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called " Pandemonium effect " is a critical problem in $\\beta$-decay if we are to test theoretically calculated transition probabilities. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the Total Absorption Spectrometer (TAS) at GSI and describe a new device LUCRECIA recently installed at CERN.

  6. Ellipsometric studies of the absorption of liquid by photo resist

    Science.gov (United States)

    Jeong, Hee; Kyung, Jaesun; Park, Songyi; Lee, Kiyong; Lee, Hyungjoo; Cheon, Hyuknyeong; An, Ilsin; Lee, Sook

    2007-03-01

    In situ spectroscopic ellipsometry, deep UV ellipsometry, and imaging ellipsometry were employed to study the absorption of liquid by photoresist(PR) used for 193 nm immersion lithography. When 140 nm thick PR was soaked in water over a period of >70 minutes, ~7% increase in thickness was observed. From the analysis of ellipsometric spectra covering from near infrared to deep UV, we could estimates less than 2 vol. % uptake of water by PR after completion of soaking. This resulted in very small decrease in refractive index of PR (~0.4%). When imaging ellipsometry was used, the absorption of water by PR in much shorter periods could be detectible. In imaging ellipsometry, the microscopic images of (Δ,Ψ ) in small area are obtained thanks to two dimensional multi-channel detection systems such as CCD. Using imaging ellipsometry, we could observe the interaction of PR with water even upon 1 s of contact. Also, we found that the water absorption or interaction was not uniform over surface. More studies are required for the implication of this observation. Obviously, imaging ellipsometry is a good technique to inspect water mark in immersion lithography. We also repeated similar experiments for high reflective index liquid (JSR HIL-001) but to find negligible change by imaging ellipsometry.

  7. EXPERIMENTAL STUDY ON NATURAL FIBRES FOR GREEN ACOUSTIC ABSORPTION MATERIALS

    Directory of Open Access Journals (Sweden)

    Lamyaa Abd ALRahman

    2013-01-01

    Full Text Available Natural fibre materials are one of the major ways to improve environmental pollution and new materials need to be considered to find the best solutions. This study presents an experimental investigation on pure micro porous materials from two types of fibres: Date Palm Fibre (DPF and Coconut Coir Fibre (CCF. This study was conducted to examine the potential for using these two types of fibres as sound absorbers. To account for the effects of the characteristics of these materials, such as thickness and density, on the acoustic absorption coefficient of a sound absorber, the measurements were conducted in an impedance tube on normal incidence acoustic absorption. The experimental data indicate that two peak values of Acoustic Absorption Coefficient (AAC are 0.98 at 1381.25 Hz-1506.25 Hz for the 40 mm thick sample and the AAC at high frequency for the same thickness is 0.99 at 4521.88-4906.25 Hz; for 20 mm thickness, the peak value is 0.84 at 2606.25-3025 Hz. The AAC of the CCF sample is 0.77 at 2434.38-2543.75 Hz for a 40 mm thickness, but for 20 mm thickness, the value is 0.71 at 4184.38-4575 Hz. The Acoustic Absorption Coefficients (AAC of the two types of materials were increased at all frequencies when the thickness of the sample was increased. The results show that date palm fibre and coconut coir fibre have good acoustic properties at low and high frequencies and can be used as an alternative replacement to conventional products. The comparisons between the two panels show a good potential because they are cheaper and lighter in comparison to asbestos and rock wool industrial materials.

  8. Use of Atomic Absorption Technique in Environmental Studies

    International Nuclear Information System (INIS)

    This chapter consists of some points including the process of atomic absorption, historical hint, key basics, the atom ionization and formation of plasma, applications in the device of atomic absorption, quantum analysis with atomic absorption, components of the device of atomic absorption, standardization of this device, atomic absorption in the the graphite furnace, supervising the analytical interventions, spectral interventions, non-spectral interventions, the utmost electric energy for atomization, preparation of standards and samples, the system of acidic digestion, similar analytical techniques.

  9. How Much Cranberry Juice Is in Cranberry-Apple Juice? A General Chemistry Spectrophotometric Experiment

    Science.gov (United States)

    Edionwe, Etinosa; Villarreal, John R.; Smith, K. Christopher

    2011-01-01

    A laboratory experiment that spectrophotometrically determines the percent of cranberry juice in cranberry-apple juice is described. The experiment involves recording an absorption spectrum of cranberry juice to determine the wavelength of maximum absorption, generating a calibration curve, and measuring the absorbance of cranberry-apple juice.…

  10. Multi-wavelength spectrophotometric determination of the protolytic constants of tetracycline hydrochloride in some nonaqueous-water mixed solvents: A solvatochromism study

    Science.gov (United States)

    Ghasemi, Jahan B.; Jalalvand, Ali R.

    2011-01-01

    Annihilation of the contribution of one chemical component from the original data matrix is a general method in rank annihilation factor analysis (RAFA). However, RAFA is not applicable for studying the protonation equilibria of multiprotic acids but in this study two-rank annihilation factor analysis (TRAFA) was used as an efficient chemometrics algorithm for determination of the protolytic constants (p Ka) of tetracycline hydrochloride (TCHC) in some nonaqueous-water mixed solvents such as acetonitrile (AN)-water and methanol (MeOH)-water from the spectral pH-absorbance data. The spectral data was obtained from spectrophotometric acid-base titrations of different solutions of TCHC at (25.0 ± 0.10) °C and an ionic strength of 0.10 M. In TRAFA algorithm the p Ka values were obtained with relationship between residual standard deviation (R.S.D.) and hypothetical p Ka values. In the case of TCHC, the spectra were divided in two consecutive subdivisions according to their pH range having two p Ka and TRAFA was run twice. The validity of the obtained p Ka values was checked with well-known chemometrics algorithms such as DATAN, EQUSPEC, SPECFIT/32 and SQUAD. The effects of changing solvent composition on the protolytic constants were explained by linear solvation energy relationships (LSER) utilizing solvatochromic parameters.

  11. SHARDS: an optical spectro-photometric survey of distant galaxies

    CERN Document Server

    Perez-Gonzalez, Pablo G; Barro, Guillermo; Villar, Victor; Cardiel, Nicolas; Ferreras, Ignacio; Rodriguez-Espinosa, Jose Miguel; Alonso-Herrero, Almudena; Balcells, Marc; Cenarro, Javier; Cepa, Jordi; Charlot, Stephane; Cimatti, Andrea; Conselice, Christopher J; Daddi, Emmanuele; Donley, Jennifer; Elbaz, David; Espino, Nestor; Gallego, Jesus; Gobat, R; Gonzalez-Martin, Omaira; Guzman, Rafael; Hernan-Caballero, Antonio; Muñoz-Tuñon, Casiana; Renzini, Alvio; Zaurin, Javier Rodriguez; Tresse, Laurence; Trujillo, Ignacio; Zamorano, Jaime

    2012-01-01

    (Abridged) We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out with GTC/OSIRIS. SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field (130 arcmin^2) at wavelengths 500 to 950 nm and using 24 contiguous medium-band filters (spectral resolution R 50). The data reach 26.5 mag (>3-sigma level) with sub-arcsec seeing in all bands. SHARDS main goal is obtaining accurate physical properties of interm- and high-z galaxies using well-sampled optical SEDs with sufficient spectral resolution to measure absorption and emission features. Among the different populations of high-z galaxies, SHARDS principal targets are massive quiescent galaxies at z>1. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures applied to the GTC/OSIRIS data. We present science demonstration results about the detection and study of emission-line galaxies (star-forming and AGN) ...

  12. Spectrophotometric estimation of roxithromycin in tablet dosage forms

    OpenAIRE

    Suhagia B; Shah S; Rathod I; Patel H; Doshi K; Parmar V

    2006-01-01

    A simple and sensitive spectrophotometric method has been developed for determination of roxithromycin in its pharmaceutical dosage forms. In the proposed method, roxithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone in the presence of ammonium acetate to give a yellow-coloured chromogen with absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml with regression...

  13. Determination of Azithromycin in pharmaceutical dosage forms by Spectrophotometric method

    OpenAIRE

    Suhagia B; Shah S; Rathod I; Patel H; Doshi K

    2006-01-01

    A simple and sensitive spectrophotometric method has been developed for determination of azithromycin in its pharmaceutical dosage forms. In the proposed method, azithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone, in the presence of ammonium acetate. A yellow coloured chromogen was obtained, having an absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml, with ...

  14. Spectrophotometric evaluation of surface morphology dependent catalytic activity of biosynthesized silver and gold nanoparticles using UV-vis spectra: A comparative kinetic study

    Science.gov (United States)

    Ankamwar, Balaprasad; Kamble, Vaishali; Sur, Ujjal Kumar; Santra, Chittaranjan

    2016-03-01

    The development of eco-friendly and cost-effective synthetic protocol for the preparation of nanomaterials, especially metal nanoparticles is an emerging area of research in nanotechnology. These metal nanoparticles, especially silver can play a crucial role in various catalytic reactions. The biosynthesized silver nanoparticles described here was very stable up to 6 months and can be further exploited as an effective catalyst in the chemical reduction of 4-nitrophenol to 4-aminophenol. The silver nanoparticles were utilized as an efficient surface-enhanced Raman scattering (SERS) active substrate using Rhodamine 6G as Raman probe molecule. We have also carried out systematic comparative studies on the catalytic efficiency of both silver and gold nanoparticles using UV-vis spectra to monitor the above reaction spectrophotometrically. We find that the reaction follows pseudo-first order kinetics and the catalytic activity can be explained by a simple model based on Langmuir-Hinshelwood mechanism for heterogeneous catalysis. We also find that silver nanoparticles are more efficient as a catalyst compare to gold nanoparticles in the reduction of 4-nitrophenol to 4-aminophenol, which can be explained by the morphology of the nanoparticles as determined by transmission electron microscopy.

  15. Acid-base and Electrochemical Properties of Manganese meso(ortho- and meta-ethylpyridyl)porphyrins: Potentiometric, Spectrophotometric and Spectroelectrochemical Study of Protolytic and Redox Equilibria

    Science.gov (United States)

    Weitner, Tin; Budimir, Ana; Batinić-Haberle, Ines

    2013-01-01

    The difference in electrostatics and reduction potentials between manganese ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP) and manganese meta-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-3-PyP) is a challenging topic, particularly because of the high likelihood for their clinical development. Hence, a detailed study of the protolytic and electrochemical speciation of MnII–IVTE-2-PyP and MnII-IVTE-3-PyP in a broad pH range has been performed using the combined spectrophotometric and potentiometric methods. The results reveal that in aqueous solutions within the pH range ~2–13 the following species exist: (H2O)MnIITE-m-PyP4+, (HO)MnIITE-m-PyP3+, (H2O)2MnIIITE-m-PyP5+, (H2O)(HO)MnIIITE-m-PyP4+, (H2O)(O=)MnIIITE-m-PyP3+, (H2O)(O=)MnIVTE-m-PyP4+ and (HO)(O=)MnIVTE-m-PyP3+ (m = 2, 3). All the protolytic equilibrium constants that include the accessible species as well as the thermodynamic parameters for each particular protolytic equilibrium have been determined. The corresponding formal reduction potentials related to the reduction of the above species and the thermodynamic parameters describing the accessible reduction couples were calculated as well. PMID:21052598

  16. Simple Spectrophotometric Methods for the Determination of Meloxicam in Presence of Its Degradation Products

    Institute of Scientific and Technical Information of China (English)

    Elham A. Taha

    2004-01-01

    Objective:To develope two simple and accurate spectrophotometric methods for the determination of meloxicam ( Ⅰ ) in presence of its degradation products, 5 - methyl - 2 - aminothiazole ( Ⅱ ) and benzothiazine carboxylic acid ( Ⅲ ). Method:Both methods are based on the formation of chelate complexes of the studied drug with uranyl acetate and ferric chloride at room temperature in a methanolic medium. Results:The resulting complexes are stable for 24 hrs and show absorption maxima at 406 nm and 580 nm for uranyl and ferric complexes respectiverecoveries of (99.44 ± 0. 48 ) % and (99. 42 ± 0. 45 ) %, and molar absorptivity of 4. 67 × 103 and 1. 029 × 103 respectively. Conclusion:Both methods are proved to be stability indicating as no interference was observed with the degradation products. The proposed methods were successfully applied to the determination of the drug in bulk powder, laboratory prepared mixtures containing different percentages of degradation products and pharmaceutical dosage forms.

  17. Spectrophotometric determination of tranexamic acid using vanillin

    Institute of Scientific and Technical Information of China (English)

    EM.A.Rind; M.G.H.Laghari; A.H.Memon; U.R.Mughal; F. Almani; N.Me-mon; M.Y.Khuhawar; M.L.Maheshwari

    2009-01-01

    A new spectrophotometric method has been examined for the determination of the tranexamic acid (TA)by derivatization with vanillin(VAN).The molar absorptivity of TA was calculated 25 160 L·mol-1·cm-1at λ max 354 nm and obeyed the Beer's law within 0.5-2.5 μg·mL-1.The color reaction was highly stable and didnot show any change in absorbance up to 24 h.The method was applied for the analysis of TA from capsules,injections and tooth pastes.The amounts of TA found in capsules,injections and tooth pastes of various pharmaceutical companies were observed with 249.0-250.9 mg/capsule,249.3-250.7 mg/injection and 0.048%-0.049%in tooth pastes with relative standard deviation(RSD)0.2%-5.0%(n=3).

  18. Spectrophotometric estimation of risperidone in tablets.

    Science.gov (United States)

    Jayanna, B K; Devaraj, T D; Roopa, K P; Nagendrappa, G; Kumar, H R Arun; Gowda, N

    2014-09-01

    A simple, rapid and highly sensitive spectrophotometric method is developed for the determination of risperidone in tablet formulation. The method is based on the oxidation of drug using potassium permanganate in alkaline medium and excess potassium permanganate oxidizes 1,10-phenanthroline Fe(II). The measurement of decrease in absorbance of 1,10-phenanthroline Fe (II) was done at 415 nm. The beer's law is obeyed in the concentration range of 5.0 to 40.0 μg/ml and molar absorptivity is found to be 7.3932 × 10(4) l/mol/cm. The proposed method is well suited for the pharmaceutical formulations. PMID:25425761

  19. Spectrophotometric estimation of risperidone in tablets

    Directory of Open Access Journals (Sweden)

    B K Jayanna

    2014-01-01

    Full Text Available A simple, rapid and highly sensitive spectrophotometric method is developed for the determination of risperidone in tablet formulation. The method is based on the oxidation of drug using potassium permanganate in alkaline medium and excess potassium permanganate oxidizes 1,10-phenanthroline Fe(II. The measurement of decrease in absorbance of 1,10-phenanthroline Fe (II was done at 415 nm. The beer′s law is obeyed in the concentration range of 5.0 to 40.0 μg/ml and molar absorptivity is found to be 7.3932 × 10 4 l/mol/cm. The proposed method is well suited for the pharmaceutical formulations.

  20. Study on Polarographic Absorption Wave of Soluble Porphyrin Copper Complex

    Institute of Scientific and Technical Information of China (English)

    HE YuFeng; ZHANG Zhang; KANG JingWan

    2001-01-01

    @@ The porphyrins is a kind of sensitive color-producing reagent. However, its selectivity is low. If the porphyrin is used in polarographic analysis, the selectivity and sensitivity can be improved. Copper is one of the most important trace element in human and mammalian body. The polarographic method is a kind of important method in determination of metal ion [1]. In this paper, meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) is used as the soluble ligand. The polarographic absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin complex with copper ion has been studied.

  1. Study on Polarographic Absorption Wave of Soluble Porphyrin Copper Complex

    Institute of Scientific and Technical Information of China (English)

    HE; YuFeng

    2001-01-01

    The porphyrins is a kind of sensitive color-producing reagent. However, its selectivity is low. If the porphyrin is used in polarographic analysis, the selectivity and sensitivity can be improved. Copper is one of the most important trace element in human and mammalian body. The polarographic method is a kind of important method in determination of metal ion [1]. In this paper, meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) is used as the soluble ligand. The polarographic absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin complex with copper ion has been studied.  ……

  2. X-ray absorption studies of battery materials

    Energy Technology Data Exchange (ETDEWEB)

    McBreen, J.

    1996-10-01

    X-ray absorption spectroscopy (XAS) is ideal for {ital in}{ital situ} studies of battery materials because both the probe and signal are penetrating x rays. The advantage of XAS being element specific permits investigation of the environment of a constituent element in a composite material. This makes it very powerful for studying electrode additives and corrosion of individual components of complex metal hydride alloys. The near edge part of the spectrum (XANES) provides information on oxidation state and site symmetry of the excited atom. This is particularly useful in study of corrosion and oxidation changes in cathode materials during charge/discharge cycle. Extended fine structure (EXAFS) gives structural information. Thus the technique provides both chemical and structural information. Since XAS probes only short range order, it can be applied to study of amorphous electrode materials and electrolytes. This paper discusses advantages and limitations of the method, as well as some experimental aspects.

  3. Studies on Steam Absorption Chillers Performance at a Cogeneration Plant

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2014-07-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers can be of either single-effect or double effect configuration and the coefficient of performance (COP depends on the selection made. The COP varies from 0.7 to 1.2 depending on the types of chillers. Single effect chillers normally have COP in the range of 0.68 to 0.79. Double effect chillers COP are higher and can reach 1.2. However due to factors such as inappropriate operations and maintenance practices, COP could drop over a period of time. In this work the performances of double effect steam absorption chillers at a cogeneration plant were studied. The study revealed that during the period of eleven years of operation the COP of the chillers deteriorated from 1.25 to 0.6. Regression models on the operation data indicated that the state of deterioration was projected to persist. Hence, it would be recommended that the chillers be considered for replacement since they had already undergone a series of costly repairs.

  4. Study on the elemental mercury absorption cross section based on differential optical absorption spectroscopy

    Science.gov (United States)

    Zheng, Haiming; Yao, Penghui

    2015-08-01

    With the method of ultraviolet absorption spectrum, the exact absorption cross-section with the light source of the low-pressure mercury lamp was determined, during which the optimum wavelength for mercury concentrations inversion was 253.69 nm, the highest detection limit was 0.177 μg/cm3, and the lowest detection limit was 0.034 μg/cm3. Furthermore, based on the differential optical absorption spectroscopy(DOAS), the relationship between the integral parameters (IP) and the concentration as well as the signal-noise ration (SNR) under the conditions of gas flow was determined and the lowest detection limit was figured out to be 0.03524 μg/cm3, providing a method of DOAS to de-noise through the comparison between the mercury concentration values produced by DOAS and that produced by the wavelet de-noising method (db5). It turned out that the differential optical absorption spectroscopy had a strong anti-interference ability, while the wavelet de-noising method was not suitable for measuring the trace concentration change.

  5. SPECTROPHOTOMETRIC ESTIMATION OF GEMFIBROZIL IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    OpenAIRE

    Parikh Vikas C.; Karkhanis V.V

    2011-01-01

    A simple, sensitive and accurate UV spectrophotometric method has been developed for the determination of Gemfibrozil in bulk and pharmaceutical tablet dosage formulation. This method obeys Beer’s law in the concentration range of 30-90 µg/ml. with correlation coefficient of 0.9993 and exhibiting maximum absorption at 276 nm with apparent molar absorptivity of 0.1703 × 104 L mole-1 cm-1. The method is accurate and precise and is extended to pharmaceutical tablet dosage forms and there was no ...

  6. Continued studies of the gastrointestinal absorption of plutonium by rodents

    International Nuclear Information System (INIS)

    An investigation is being made of the absorption of plutonium from the gastrointestinal tract of rodents. In the mouse it has been found to be essentially independent of the oxidation state of plutonium and the administration medium. In the rat the absorption was higher than it was in the mouse, but not appreciably so. The values obtained for both mice and rats are about two orders of magnitude higher than the value adopted for the gastrointestinal absorption factor for plutonium in man

  7. Fading Spectrophotometric Method for the Determination of Polyvinylpyrrolidone with Eosin Y

    Institute of Scientific and Technical Information of China (English)

    YU Lihong; LIU Zhongfang; LIU Shaopu; HU Xiaoli; LIU Linfeng

    2009-01-01

    In weak acid medium,eosin Y (EY) has a strong absorption band in the visible light region,and the maximum absorption wavelength (λmax) is at 517 nm.There is no light absorption for polyvinylpyrrolidone (PVP) in 250-700 nm.When EY was reacted with PVP to form a binding product,a fading reaction of EY appeared and the maximum fading wavelength was still located at 517 nm.At the same time,a smaller absorption peak was observed at 545 nm.The extent of the fading (△A) is directly proportional to the concentration of PVP in the range of 0.40-3.20 mg·L-1.The fading reaction has high sensitivity.The molar absorptivity (ε) is 6.4×106 L·mol 1·cm-1 and the detection limit for PVP is 0.12 mg·L-1.The influencing factors for the reaction have been studied,and the results show that the selectivity is good.Based on this fact,a new fading spectrophotometric method for the determination of PVP with EY has been developed,which is simple and rapid,and it can be applied to the quantitative determination of PVP in beer samples.

  8. Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: potentiometric, spectrophotometric and spectroelectrochemical study of protolytic and redox equilibria.

    Science.gov (United States)

    Weitner, Tin; Budimir, Ana; Kos, Ivan; Batinić-Haberle, Ines; Biruš, Mladen

    2010-12-28

    The difference in electrostatics and reduction potentials between manganese ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP) and manganese meta-tetrakis(N-ethylpyridinium-3-yl)porphyrin (MnTE-3-PyP) is a challenging topic, particularly because of the high likelihood for their clinical development. Hence, a detailed study of the protolytic and electrochemical speciation of Mn(II-IV)TE-2-PyP and Mn(II-IV)TE-3-PyP in a broad pH range has been performed using the combined spectrophotometric and potentiometric methods. The results reveal that in aqueous solutions within the pH range ∼2-13 the following species exist: (H(2)O)Mn(II)TE-m-PyP(4+), (HO)Mn(II)TE-m-PyP(3+), (H(2)O)(2)Mn(III)TE-m-PyP(5+), (HO)(H(2)O)Mn(III)TE-m-PyP(4+), (O)(H(2)O)Mn(III)TE-m-PyP(3+), (O)(H(2)O)Mn(IV)TE-m-PyP(4+) and (O)(HO)Mn(IV)TE-m-PyP(3+) (m = 2, 3). All the protolytic equilibrium constants that include the accessible species as well as the thermodynamic parameters for each particular protolytic equilibrium have been determined. The corresponding formal reduction potentials related to the reduction of the above species and the thermodynamic parameters describing the accessible reduction couples were calculated as well. PMID:21052598

  9. Spectrophotometric Determination of Certain Benzimidazole Proton Pump Inhibitors

    Science.gov (United States)

    Syed, A. A.; Syeda, Ayesha

    2008-01-01

    Spectrophotometric method for the determination of certain proton pump inhibitors belonging to the benzimidazole class of compounds has been developed. The method is based on the reaction of omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole with iron (III) and subsequent reaction with ferricyanide under neutral condition which yields Prussian blue product with maximum absorption at 720–730 nm. The commonly encountered excipients and additives that often accompany pharmaceutical preparations did not interfere with the determination. The method was applied for the determination of omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole in pharmaceutical preparations and no difference was found statistically. Thus, the spectrophotometric method can be applied as inexpensive, rapid, easy, accurate and precise method for the routine analysis of the five proton pump inhibitors in pharmaceutical preparations. PMID:20046782

  10. Spectrophotometric determination of certain benzimidazole proton pump inhibitors

    Directory of Open Access Journals (Sweden)

    Syed A

    2008-01-01

    Full Text Available Spectrophotometric method for the determination of certain proton pump inhibitors belonging to the benzimidazole class of compounds has been developed. The method is based on the reaction of omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole with iron (III and subsequent reaction with ferricyanide under neutral condition which yields Prussian blue product with maximum absorption at 720-730 nm. The commonly encountered excipients and additives that often accompany pharmaceutical preparations did not interfere with the determination. The method was applied for the determination of omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole in pharmaceutical preparations and no difference was found statistically. Thus, the spectrophotometric method can be applied as inexpensive, rapid, easy, accurate and precise method for the routine analysis of the five proton pump inhibitors in pharmaceutical preparations.

  11. Method development for arsenic analysis by modification in spectrophotometric technique

    Directory of Open Access Journals (Sweden)

    M. A. Tahir

    2012-01-01

    Full Text Available Arsenic is a non-metallic constituent, present naturally in groundwater due to some minerals and rocks. Arsenic is not geologically uncommon and occurs in natural water as arsenate and arsenite. Additionally, arsenic may occur from industrial discharges or insecticide application. World Health Organization (WHO and Pakistan Standard Quality Control Authority have recommended a permissible limit of 10 ppb for arsenic in drinking water. Arsenic at lower concentrations can be determined in water by using high tech instruments like the Atomic Absorption Spectrometer (hydride generation. Because arsenic concentration at low limits of 1 ppb can not be determined easily with simple spectrophotometric technique, the spectrophotometric technique using silver diethyldithiocarbamate was modified to achieve better results, up to the extent of 1 ppb arsenic concentration.

  12. Spectrophotometric determination of diloxanide furoate in its dosage forms.

    Science.gov (United States)

    Al-Ghanam, S M; Belal, F

    2001-09-01

    A simple and sensitive spectrophotometric method has been developed for the determination of diloxanide furoate in its dosage forms. The method is based on the reaction of the drug with potassium permanganate in the presence of sodium hydroxide to produce a bluish green coloured species measurable at 610 nm. The absorbance-concentration plot is linear over the range 2.5-20 microg/ml with correlation coefficient (n = 8) of 0.9998 and minimum detectability of 0.2 microg/ml (6.1 x 10(-7) M). The molar absorptivity was 1.1 x 10(4) l/mol cm. The different experimental parameters affecting the development and stability of the colour were carefully studied and optimised. The proposed method was applied successfully for the determination of diloxanide furoate in its tablet form. The results obtained were in good agreement with those obtained using the official method. The proposed method could be applied to the determination of diloxanide furoate in presence of some co-formulated drugs. The effect of sensitisers and surfactants on the performance of the proposed method was also studied. A proposal of the reaction pathway was presented. PMID:11680811

  13. Spectrophotometric evaluation of optical performances of polarizing technologies for smart window applications

    International Nuclear Information System (INIS)

    In recent years, window-integrated solar protection systems are used and studied as a promising energy saving technology, both for cold and hot climates. In particular, smart windows, whose optical proprieties in the solar wavelength range can somehow be controlled, show interesting results, especially in reducing the air conditioning power consumption. With the improvement of nanolithography techniques as well as with the possibility of designing polarization intervals, coupled polarizing films show a good potential as a dynamic and wavelength-selective shading technology. In this paper, UV-Vis-NIR spectrophotometric measurements are carried out on two polarizing technologies, Polaroid crystalline polarizer and Wire Grid broadband polarizer, in single- and double- film layout, to evaluate their optical performances, i.e. spectral transmittance, reflectance and absorptivity. The solar radiation glazing factors, according to the standard UNI EN 410, are calculated. The measured data are also analyzed in detail to emphasize the optical peculiarities of the materials under study that do not stand out from the standard parameters, as well as the specific problems that arise in spectrophotometric evaluations of polarizing films

  14. SPECTROPHOTOMETRIC DETERMINATION OF CHLOROPHYLLS AND CAROTENOIDS. AN EFFECT OF SONICATION AND SAMPLE PROCESSING

    Directory of Open Access Journals (Sweden)

    Jana Braniša

    2014-02-01

    Full Text Available Chlorophylls and carotenoids are abundant pigments in plants, algae and cyanobacteria. In this study we verified the applicability of two previously developed UV-vis spectrophotometric methods for simultaneous quantitative determination of chlorophylls (a, b and carotenoids (lycopene, β-carotene or total carotenoids. The pigments were extracted from the strawberries, apricots and raspberries in both the acetone-water and acetone-hexane mixtures. Based on the statistical evaluation of the results the combination of mechanical disruption and sonication of fruit samples seems to be a suitable way to improve the pigment extraction efficiency from fruits in both types of solvents. In the case of apricot and raspberry fruit extracts the amount of chlorophylls and carotenoids calculated from the proposed equations was comparable to those published by other authors. However, the spectrophotometric determination of β-carotene content in strawberry acetone-hexane extract appeared to be problematic mainly due to the fact that carotenoids exhibited overlapping chlorophyll absorption bands. Overlap of bands leads to the negative values calculated from the proposed equation for the β-carotene content. The results indicate the limitations in use of the proposed set of equations for plant samples with comparable amounts of studied pigments.

  15. STOPPED-FLOW SPECTROPHOTOMETRIC STUDIES OF THE KINETICS OF INTERACTION OF DIHYDROXYFUMARIC ACID WITH THE DPPH FREE RADICAL

    OpenAIRE

    N. Secara

    2010-01-01

    The reaction of dihydroxyfumaric acid with the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was studied using the stopped-flow method, in order to describe the reaction kinetics. Dihydroxyfumaric acid reacts very rapidly with DPPH, the reaction being completed in several minutes. This 2-stoichiometric reaction proceeds in two stages, with reaction orders of 1 and 0.76 with respect to DPPH, and 0.5 and 0.3 with respect to DHF, respectively. The rate constant of the two stages of the react...

  16. Spectrophotometric retinal oximetry in pigs

    DEFF Research Database (Denmark)

    Traustason, Sindri; Kiilgaard, Jens Folke; Karlsson, Robert;

    2013-01-01

    PURPOSE: To assess the validity of spectrophotometric retinal oximetry, by comparison to blood gas analysis and intra-vitreal measurements of partial pressure of oxygen (pO2). METHODS: Female domestic pigs were used for all experiments (n=8). Oxygen fraction in inspired air was changed using......, Reykjavik, Iceland). The device simultaneously acquires images at two wavelengths (570 nm and 600 nm) and specialized software automatically detects retinal blood vessels. In three pigs, invasive pO2-measurements were performed after the initial non-invasive measurements. RESULTS: Comparison of femoral......-measurements in three pigs. This relationship was approximately linear (R(2) = 0.45, p = 0.04). CONCLUSIONS: Non-invasive spectrophotometric oximetry is sensitive to changes in oxygen saturation in pigs and correlated with intravitreal pO2-measurements and with femoral artery pO2. Pigs present a higher intra...

  17. Povidone iodine skin absorption: an ex-vivo study.

    Science.gov (United States)

    Nesvadbova, Martina; Crosera, Matteo; Maina, Giovanni; Larese Filon, Francesca

    2015-06-15

    Povidone iodine is a water-soluble complex used to disinfect the skin surface and it exerts prolonged germicidal action against a broad spectrum of germs. Indeed, it is often applied on burned skin, large wounds, deep tissues or mucosa. Notably some surgical hand-scrub solutions, which are considered safe antiseptics, contain large amounts of iodine that can be absorbed by skin. The aim of present study was to study the skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure. We use Franz diffusion static cells with human skin. After 24h from the beginning of our measurement the iodine concentration in the receiving compartment was 11.59±6.3μg/cm(2). The medium flux calculated was 0.73±0.33μg/cm(2)/h with a lag time of 8.9±1.5h. These in vitro results confirmed that povidone iodine could pass through the skin in a relevant amount that can explain the clinical findings in burned or surgically treated patients. In professional use the repetitive contact with povidone iodine, also as soap, can cause iodine skin permeation that must be considered when the washing procedures are repeated more than 20 times a day.

  18. Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅰ. Absorption of Hydrogen by Hydrogen Storage Alloy MlNi5 Suspended in Benzene

    Institute of Scientific and Technical Information of China (English)

    安越; 陈长聘; 徐国华; 蔡官明; 王启东

    2002-01-01

    The absorption of hydrogen was studied in metal hydride slurry, which is formed by benzene and hydrogen storage alloy powder. The influence of temperature on the rate of absorption was discussed using three-phase mass transfer model. It is also concluded that the suitable absorption temperature is 313 K.

  19. A Spectrophotometric Study of Plumage Color in the Eared Dove (Zenaida auriculata, the Most Abundant South American Columbiforme.

    Directory of Open Access Journals (Sweden)

    Diego Javier Valdez

    Full Text Available For birds, plumage color perception is critical in social interactions such as courtship, in both monochromatic and dichromatic species. In the Eared Dove (Zenaida auriculata, perhaps the most abundant South American Columbiforme, the plumage of males and females looks alike and both sexes share the same melanistic coloration with gray and pink tones. The aim of this study was therefore to determine whether evident sexual dichromatism exists in the plumage of the Eared Dove using a spectrophotometry technique in the avian-visible range (300-700 nm. The results of the classic colorimetric variables analysis (hue, chroma and brightness show that males are in general brighter and have higher UV chroma values than females. The avian visual model points to differences in achromatic and chromatic levels between males and females in body regions possibly involved in sexual selection (e.g. the crown. The model also indicates chromatic or achromatic differences in body regions not subject to sexual selection such as the black spots on the wing coverts and white tail bands, both of which may be involved in intra- or inter-gender-specific communication.

  20. A Spectrophotometric Study of Plumage Color in the Eared Dove (Zenaida auriculata), the Most Abundant South American Columbiforme.

    Science.gov (United States)

    Valdez, Diego Javier; Benitez-Vieyra, Santiago Miguel

    2016-01-01

    For birds, plumage color perception is critical in social interactions such as courtship, in both monochromatic and dichromatic species. In the Eared Dove (Zenaida auriculata), perhaps the most abundant South American Columbiforme, the plumage of males and females looks alike and both sexes share the same melanistic coloration with gray and pink tones. The aim of this study was therefore to determine whether evident sexual dichromatism exists in the plumage of the Eared Dove using a spectrophotometry technique in the avian-visible range (300-700 nm). The results of the classic colorimetric variables analysis (hue, chroma and brightness) show that males are in general brighter and have higher UV chroma values than females. The avian visual model points to differences in achromatic and chromatic levels between males and females in body regions possibly involved in sexual selection (e.g. the crown). The model also indicates chromatic or achromatic differences in body regions not subject to sexual selection such as the black spots on the wing coverts and white tail bands, both of which may be involved in intra- or inter-gender-specific communication. PMID:27213273

  1. [Study of retrieving formaldehyde with differential optical absorption spectroscopy].

    Science.gov (United States)

    Li, Yu-Jin; Xie, Pin-Hua; Qin, Min; Qu, Xiao-Ying; Hu, Lin

    2009-01-01

    The present paper introduces the method of retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS). The authors measured ambient HCHO in Beijing region with the help of differential optical absorption spectroscopy instrument made by ourself, and discussed numerous factors in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), especially, the choice of HCHO wave band, how to avoid absorption of ambient SO2, NO2 and O3, and the influence of the Xenon lamp spectrum structure on the absorption of ambient HCHO. The authors achieved the HCHO concentration by simultaneously retrieving the concentrations of HCHO, SO2, NO2 and O3 with non-linear least square fitting method, avoiding the effect of choosing narrow wave of HCHO and the residual of SO2, NO2, O3 and the Xenon lamp spectrum structure in retrieving process to attain the concentration of HCHO, Finally the authors analyzed the origin of error in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), and the total error is within 13.7% in this method. PMID:19385238

  2. A multi-epoch spectroscopic study of the BAL quasar APM 08279+5255: I. C IV absorption variability

    CERN Document Server

    Trevese, D; Vagnetti, F; Perna, M; Paris, D; Turriziani, S

    2013-01-01

    Broad Absorption Lines indicate gas outflows with velocities from thousands km/s to about 0.2 the speed of light, which may be present in all quasars and may play a major role in the evolution of the host galaxy. The variability of absorption patterns can provide informations on changes of the density and velocity distributions of the absorbing gas and its ionization status. We collected 23 photometrical and spectro-photometrical observations at the 1.82m Telescope of the Asiago Observatory since 2003, plus other 5 spectra from the literature. We analysed the evolution in time of the equivalent width of the broad absorption feature and two narrow absorption systems, the correlation among them and with the R band magnitude. We performed a structure function analysis of the equivalent width variations. We present an unprecedented monitoring of a broad absorption line quasar based on 28 epochs in 14 years. The shape of broad absorption feature shows a relative stability, while its equivalent width slowly decline...

  3. Solid-liquid Extraction Spectrophotometric Determination of Copper with 2,9-dimethyl-1, 10-phenanthroline

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solid liquid extraction of copper ion (I) with 2, 9-dimethyl-1, 10-phenanthroline (neo-cuproine, DMP) into molten naphthalene followed by chloroform spectrophotometric determination has been studied experimentally. The ternary complex Cu(I)-DMP-ClO4 was extracted quantitatively into molten naphthalene in the range of pH from 5 to 6 at 85℃. Absorbance was spectrophotometrically determined at 459 nm against the reagent blank after the solid naphthalene layer was anhydrously dissolved in chloroform. Beer's law is obeyed over a concentration range of 0.5-70 mg/mL. The molar absorptivity and Sandell's sensitivity are 1.0′104 L/(mol·cm) and 0.0099 mg·cm2 respectively. In addition, the various conditions on determination and the interference of coexisted ions were discussed, and the method was applied to the determination of copper ion both in tea samples and cadmium sulfate reagents. The results are in good agreement with those obtained by ICP AES method.

  4. [Spectrophotometric determination of protein content in THP-1 monocytes/macrophages - description of the method].

    Science.gov (United States)

    Wolska, Jolanta; Janda, Katarzyna; Gutowska, Izabela

    2015-01-01

    Proteins are the basic building block of tissue, and are part of enzymes and hormones regulating many important life processes. Changes in their concentration control the metabolic processes of the cell. Quantitative determination of the protein content is divided into indirect methods (e.g. Kjeldahl method) and direct methods (buret method, Lowry, immunoenzymatic, formol method, based on incorporation of dye in the range of ultraviolet spectrophotometry, and based on the phenomenon of selective absorption of radiation in the infrared range). One of the methods for the determination of protein content is the spectrophotometric method described by Bradford. The protein concentration assay procedure utilizes the phenomenon of formation of the dye (Coomassie Brillant Blue G-250)-protein and colour intensity is proportional to the protein content in the solution. The aim of this study was to verify the usefulness of this method for determining the protein content in THP-1 cells cultured with extracts of nettle fruit stalks (Urtica dioica L.). Aqueous and alcohol extracts at two concentrations were used. It has been shown that the spectrophotometric determination of protein content by the Bradford method is an effective and accurate method for determining the concentration of protein in THP-1 macrophages. The results indicate that this method can be recommended for the determination of the protein content in other cell cultures.

  5. Theoretical Study of New Combined Absorption-Ejector Refrigeration System

    Science.gov (United States)

    Abed, A. M.; Sopian, K.; Alghoul, M. A.; Al-Shamani, A. N.; Ruslan, M. H.; Mat, S.

    2015-09-01

    An improved system of the new combined single stage absorption cycle operated with NH3/H2O as working fluid was performed. In order to enhance performance the cycle a new configuration of absorption system was utilized. The performances of two configurations of the combined absorption cycle were compared; a) with common solution heat exchanger and b) divided the streamline of solution heat exchanger to recover the internal heat. Based on the analysis, it has been shown that the second configuration a significant reduction of the required generator and absorber loads by about 20% and 17% respectively, with increased coefficient of performance (COP) about 12% compared to the first configuration. This improvement in the overall COP is found due to improve energy utilization efficiency significantly.

  6. Protonation effects on the UV/Vis absorption spectra of imatinib: A theoretical and experimental study

    Science.gov (United States)

    Grante, Ilze; Actins, Andris; Orola, Liana

    2014-08-01

    An experimental and theoretical investigation of protonation effects on the UV/Vis absorption spectra of imatinib showed systematic changes of absorption depending on the pH, and a new absorption band appeared below pH 2. These changes in the UV/Vis absorption spectra were interpreted using quantum chemical calculations. The geometry of various imatinib cations in the gas phase and in ethanol solution was optimized with the DFT/B3LYP method. The resultant geometries were compared to the experimentally determined crystal structures of imatinib salts. The semi-empirical ZINDO-CI method was employed to calculate the absorption lines and electronic transitions. Our study suggests that the formation of the extra near-UV absorption band resulted from an increase of imatinib trication concentration in the solution, while the rapid increase of the first absorption maximum could be attributed to both the formation of imatinib trication and tetracation.

  7. Zinc absorption study using an enriched stable isotope (70Zn)

    International Nuclear Information System (INIS)

    A weaning food from fermented soybean was prepared for increasing the bioavailability of zinc. The zinc absorption was compared with that of a weaning food from non-fermented soybean and normal staple food. A stable isotope tracer technique (70Zn) and neutron activation were used for determining the absorption of zinc. Nine children aged 7 to 18 months were tested. Zinc bioavailability of weaning food from fermented soybean is higher than that of normal weaning food. The weight increment and zinc nutrition of children having weaning food from fermented soybean are improved by this diet. 5 tabs

  8. Study of UCI4 structure and absorption spectra

    International Nuclear Information System (INIS)

    The two halides ThCl4 and ThBr4, which are isomorphic at room temperature, have a comparable behaviour when the temperature is lowered. The resonance line of the halogen isotope is split into two lines at a temperature of 96 K for ThBr4 and 70 K for ThCl4. These data confirm the observation of a phase transition first detected by Raman Spectroscopy. Though UCl4 is isomorphic with ThCl4 and ThBr4 at room temperature, it behaves differently versus temperature. The experiments performed from 4,2K to room temperature showed there is only one site for the halogen. UCl4 does not present a phase transition. Once some informations have been gathered on the matrices, optical absorption spectra on ThCl4:U4+ and UCl4 monocristals have been recorded in the visible and infrared ranges at 4,2 K and at room temperature. These spectra have many vibronic lines. To give a first interpretation of the pure electronic lines of U4+-ThCl4 and UCl4 studies on U4+-ThBr4 have been used, in particular the zero phonon lines which correspond to a Dsub(2d) symmetry, have been selected in comparison with the work done on ThBr4:U4+. The energy levels in ThCl4:U4+ and UCl4 have been fitted to the electrostatic parameters F0, F2,F4, F6, the spin orbit parameter, the configuration interaction parameters α, β, γ and crystal field parameters B02, B04, B44, B06, B46

  9. Visible spectrophotometric determination of valdecoxib in tablet dosage forms

    Directory of Open Access Journals (Sweden)

    Suganthi A

    2006-01-01

    Full Text Available A simple, accurate, rapid, and sensitive visible spectrophotometric method has been developed for the determination of valdecoxib in pure and pharmaceutical dosage forms. The method is based on the reaction of valdecoxib with potassium permanganate to form a bluish green coloured chromogen with an absorption maximum at 610 nm. Beer′s law was obeyed in the range of 5-25 mg/ml. The proposed method has been successfully applied to the analysis of the bulk drug and its dosage forms

  10. Shards: an optical spectro-photometric survey of distant galaxies

    OpenAIRE

    Pérez-González, P. G.; Cava, A; Rodríguez-Espinosa, J. M.; Alonso-Herrero, A.; Cepa, Jordi; Donley, J. L.; Gallego, Jesús; González-Martín, Omaira; Hernán-Caballero, Antonio; Rodríguez Zaurín, Javier

    2013-01-01

    We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin2 at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R ∿ 50). The data reach an AB magnitude of 26.5 (at least at a 3σ level) with sub-arcsec seeing i...

  11. Visible spectrophotometric estimation of diacerein in bulk and pharmaceutical dosage forms.

    Science.gov (United States)

    Sivakumar, R; Nallasivan, Pk; Saranya, Kc; Sam, Solomon Wd; Akelesh, T; Venkatnarayanan, R

    2010-10-01

    Two simple, sensitive, accurate, rapid, and economical spectrophotometric methods have been developed for the estimation of diacerein in Pharmaceutical dosage forms. Method A is based on the reaction of diacerein with Folin-Ciocalteu reagent, in the presence of 0.5 N sodium hydroxide solution, giving a pink-colored chromogen, which shows maximum absorbance at 512 nm against reagent blank, while method B is based on the oxidation of diacerein with potassium permanganate in an alkaline medium giving a pink-colored chromogen, which shows maximum absorption at 497.5 nm. Beer's law was obeyed in the concentration range of 4 - 20 µg/ml for both methods A and B. Results of the analysis were validated statistically, and by recovery studies. PMID:21264105

  12. Simultaneous spectrophotometric determination of amlodipine besylate and atorvastatin calcium in binary mixture

    Directory of Open Access Journals (Sweden)

    Sahu R

    2007-01-01

    Full Text Available A rapid, simple, accurate and precise UV Spectrophotometric method using simultaneous equation was developed for the simultaneous determination of amlodipine besylate and atorvastatin calcium in a binary mixture. In the proposed method, the signals were measured at 238.2 and 246.6 nm corresponding to the absorbance maxima of amlodipine besylate and atorvastatin calcium in methanol, respectively. Linearity was observed in the concentration range of 5-30 µg/ml for both the drugs. Concentration of each drug was obtained by using the absorptivity values calculated for both the drugs at two wavelengths, 238.2 and 246.6 nm and solving the simultaneous equations. The method was validated statistically and recovery study was performed to confirm the accuracy of the method. Laboratory prepared synthetic mixture was successfully analyzed using the developed method.

  13. 21-cm absorption studies with the Square Kilometer Array

    NARCIS (Netherlands)

    Kanekar, N; Briggs, FH

    2004-01-01

    HI 21-cm absorption spectroscopy provides an excellent probe of the neutral gas content of absorbing galaxies, yielding information on their kinematics, mass, physical size and ISM conditions. The high sensitivity, unrivaled frequency coverage and RFI suppression techniques of the SKA will enable it

  14. SOLID PHASE SPECTROPHOTOMETRIC DETERMINATION OF SELENIUM(IV) USING DITHISONE IMMOBILIZED IN A POLYMETHACRYLATE MATRIX

    OpenAIRE

    Gavrilenko, N. A.; Saranchina, N. V.; Gavrilenko, M. A.

    2014-01-01

    This paper presents a solid-phase spectrophotometric method for the determination selenium(IV). The proposed method is based on the reaction between the selenium(IV) and dithizone immobilized into transparent polymethacrylate matrix in strongly acidic solution. It was shown that the interaction of selenium(IV) with dithizone in solid phase was accompanied by the formation of the complex with an absorption maximum 420 nm. The change of absorption at wavelength 610 nm corresponding to absorptio...

  15. A study of selective spectrophotometric methods for simultaneous determination of Itopride hydrochloride and Rabeprazole sodium binary mixture: Resolving sever overlapping spectra

    Science.gov (United States)

    Mohamed, Heba M.

    2015-02-01

    Itopride hydrochloride (IT) and Rabeprazole sodium (RB) are co-formulated together for the treatment of gastro-esophageal reflux disease. Three simple, specific and accurate spectrophotometric methods were applied and validated for simultaneous determination of Itopride hydrochloride (IT) and Rabeprazole sodium (RB) namely; constant center (CC), ratio difference (RD) and mean centering of ratio spectra (MCR) spectrophotometric methods. Linear correlations were obtained in range of 10-110 μg/μL for Itopride hydrochloride and 4-44 μg/mL for Rabeprazole sodium. No preliminary separation steps were required prior the analysis of the two drugs using the proposed methods. Specificity was investigated by analyzing the synthetic mixtures containing the two cited drugs and their capsules dosage form. The obtained results were statistically compared with those obtained by the reported method, no significant difference was obtained with respect to accuracy and precision. The three methods were validated in accordance with ICH guidelines and can be used for quality control laboratories for IT and RB.

  16. An alternative method study for determining the content oils and greases derived from spectrophotometric; Estudo de um metodo alternativo para determinacao de oleos e graxas derivado do metodo espectrofotometrico

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Leila Rose Benevides; Bezerra, Magna Angelica dos Santos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Recursos Humanos da ANP, PRH-14; Melo, Josette Lourdes de Sousa; Melo, Henio Normando de Sousa [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Gomes, Andrea Karla Martins [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia Quimica

    2004-07-01

    The determination of the Text of Oils and Greases (TOG) it can be done by several methods - gravimetrical or spectrophotometric. That work seeks to study a method alternative spectrophotometric, being compared this with the method used by Curbelo (2002). The modifications were: the reason solvent/sample, and the procedure in which the solvent the sample was mixed. For the method of Curbelo (2002) 100 mL of the sample was mixed to 10 chloroform mL and separated in separation funnel. In the proposed method, adapted denominated Chloroform, the reason was of 20 sample mL for 20 chloroform mL, being this mixture, after manual agitation, taken directly for centrifuge. The medium results were of 81,36 mg/L and 150,44 mg/L for the methods of the Chloroform and Adapted Chloroform, respectively. In spite of the medium values they present differences of almost 50%, it can be verified that the methods demonstrated certain uniformity when evaluated separately, being obtained a minimum deviation of 5,88%. With base in those preliminary results, it can be verified that the developed alternative method gets to remove more oil, mainly for more concentrated samples - exception done to the results of the pattern - and that the two methods present viability of substitution of the gravimetrical methods. (author)

  17. Spectrophotometric determination of thioctic (a-Aipoic acid in water and pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    ZAGORKA KORICANAC

    2007-01-01

    Full Text Available A spectrophotometric method is described for the assay of thioctic acid. The method is based on the reaction between the drug and palladium(II chloride. In this reaction, a yellow-coloured, water soluble product with a 1:1 stoichiometric ratio and an absorption maximum at 365 nm was formed. The stability of the formed complex depends on various factors (pH, reaction time, concentration of reagents, ionic strength. Based on these findings, a new method is suggested for the spectrophotometric determination of thioctic acid in pharmaceutical formulations. This method is simple, sensitive and reproducible.

  18. Photo absorption studies of polyatomic molecules using Indus 1 synchrotron radiation source

    International Nuclear Information System (INIS)

    The Photophysics beamline is a medium resolution beamline designed for carrying out photo absorption and fluorescence experiments using the synchrotron radiation source Indus-l. This beamline has been commissioned recently and is in operation. An experimental setup for gas phase absorption studies has been developed and installed. Absorption spectra of a few polyatomicmolecules viz. benzene, ammonia, carbon disulphide and acetone were recorded in the wavelength region 1500 -3000 A. The results from this study indicated the satisfactory performance of the beam line as well as the experimental setup. Details of the first set of absorption experiments carried out are discussed in this report. (author)

  19. CdTe Nanowires studied by Transient Absorption Microscopy

    Directory of Open Access Journals (Sweden)

    Kuno M.

    2013-03-01

    Full Text Available Transient absorption measurements were performed on single CdTe nanowires. The traces show fast decays that were assigned to charge carrier trapping at surface states. The observed power dependence suggests the existence of a trap-filling mechanism. Acoustic phonon modes were also observed, which were assigned to breathing modes of the nanowires. Both the fundamental breathing mode and the first overtone were observed, and the dephasing times provide information about how the nanowires interact with their environment.

  20. In vitro absorption studies of acyclovir using natural permeation enhancers

    OpenAIRE

    Dias, Remeth J.; Mali, Kailas K.; Ghorpade, Vishwajeet S.; Garje, Sandeep B.; Havaldar, Vijay D.

    2010-01-01

    Gastroretentive Delivery Systems are employed to improve the bioavailability of drugs which are absorbed through upper part of GIT, by increasing their retention time. Incorporation of permeability enhancers in the formulations of such drugs can further increase their bioavailability; however their use in the formulations is questionable due to the toxicity exhibited by them. Acyclovir is a class III drug having low oral bioavailability due to improper absorption. Mucoadhesive tab...

  1. Study on hydrogen absorption/desorption properties of uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen absorption/desorption properties of two U-Mn intermetallic compounds, U{sub 6}Mn and UMn{sub 2}, were investigated. U{sub 6}Mn absorbed hydrogen and the hydrogen desorption pressure of U{sub 6}Mn obtained from this experiment was higher than that of U, which was considered to be the effect of alloying, whereas UMn{sub 2} was not observed to absorb hydrogen up to 50 atm at room temperature. (author)

  2. Studies on the red absorption band of chlorophyll a in vivo

    NARCIS (Netherlands)

    Thomas, J.B.; Kleinen Hammans, J.W.; Arnolds, W.J.

    1965-01-01

    It was studied whether certain earlier observed weak shoulders on the red absorption band of chlorophyll a in vivo might represent anomalies due to overlap of absorption bands. The results are suggested of the fact that no such anomalies occur. It is therefore concluded that the present study suppo

  3. Application of inorganic oxidants to the spectrophotometric determination of ribavirin in bulk and capsules.

    Science.gov (United States)

    Darwish, Ibrahim A; Khedr, Alaa S; Askal, Hassan F; Mohamed, Ramadan M

    2006-01-01

    Eight spectrophotometric methods for determination of ribavirin have been developed and validated. These methods were based on the oxidation of the drug by different inorganic oxidants: ceric ammonium sulfate, potassium permanganate, ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate. The oxidation reactions were performed in perchloric acid medium for ceric ammonium sulfate and in sulfuric acid medium for the other reagents. With ceric ammonium sulfate and potassium permanganate, the concentration of ribavirin in its samples was determined by measuring the decrease in the absorption intensity of the colored reagents at 315 and 525 nm, respectively. With the other reagents, the concentration of ribavirin was determined by measuring the intensity of the developed colored reaction products at the wavelengths of maximum absorbance: 675, 780, 595, 595, 475, and 475 nm for reactions with ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate, respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9984-0.9998) were found between the absorbance readings and the concentrations of ribavirin in the range of 4-1400 microg/mL. The molar absorptivities were correlated with the oxidation potential of the oxidants used. The precision of the methods were satisfactory; the values of relative standard deviation did not exceed 1.64%. The proposed methods were successfully applied to the analysis of ribavirin in pure drug material and capsules with good accuracy and precision; the recovery values were 99.2-101.2 +/- 0.48-1.30%. The results obtained using the proposed spectrophotometric methods were comparable with those obtained with the official method stated in the United States Pharmacopeia. PMID

  4. Optical absorption and fluorescence studies on imidazolium ionic liquids comprising the bis(trifluoromethanesulphonyl)imide anion

    Indian Academy of Sciences (India)

    Aniruddha Paul; Anunay Samanta

    2006-07-01

    Optical absorption and fluorescence behaviour of two rigorously purified imidazolium ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide are studied in the neat condition and in solution. Non-negligible absorption in the UV region with a long tail extending into the visible region is the main feature of the absorption. Excitation wavelength-dependent two-component fluorescence characterizes the emission behaviour of these liquids. That ion association gives rise to the long absorption tail and shifting fluorescence maximum, which appears to be common to most of the imidazolium ionic liquids, is evident from the effect of the conventional solvents.

  5. Study on the dynamics in absorption of 32P by hybrid wheat at elongate stage

    International Nuclear Information System (INIS)

    The dynamics of absorbing 32P of hybrid wheat at elongate stage is studied under pot culture conditions. The results show that the absorption capacity of hybrid wheat to 32P is in agreement with regression equation. The increased extent of absorption for them is greater than that for parent with time, and the reduction rate of absorption is lower than the parent significantly. Their root activity is much higher than that of the parent, too. The overall heterotic vigor of hybrid wheat on the absorption capacity to 32P is the sum of that of all organs

  6. Spectrophotometric study of Co(II, Ni(II, Cu(II, Zn(II, Pd(II and Hg(II complexes with isatin- β-thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    SANDRA S. KONSTANTINOVIC

    2007-10-01

    Full Text Available The composition and stability of the complexes of isatin-b-thiosemicarba­zone with Co(II, Ni(II, Cu(II, Zn(II, Pd(II and Hg(II have been investigated us­ing spectrophotometric method at 30 °C and constant ionic strength of 0.1 mol dm-3 (KNO3 in 70 % ethanol. Experimental results indicate the formation of MeL and MeL2 complexes for Ni(II and Co(II, and MeL for Cu(II, Zn(II, Pd(II and Hg(II complexes, whose stability constants, bn, have been calculated using a com­puteri­zed iterative method of successive approximation.

  7. Study on Differential Optical Absorption Spectroscopy : Technique and its Applications

    OpenAIRE

    Liu, Jianguo

    2002-01-01

    ln the first part of speech, with a description of the principle of DOAS (Differential Optical Absorption Spectroscopy), the design and realization of two different kinds of DOAS systems are nresented. 0ne is using a slotted disc raoid scanning device with a photomultiplier, which is suitable for ambient air quality measurement. It can measure total 16 kinds of pollutants such as SO_2, NO, N02, NH_3, O_3, C_6H_6, C_7H_8 and CH_2O etc., with detection limits of 1-2ppb. The other is using a UV ...

  8. Spectrophotometric determination of the fungicide captan.

    Science.gov (United States)

    Galeano, Teresa; Guiberteau, Agustina; Mora, Nielene M; Alvarez, Pedro R; Salinas, Francisco

    2002-11-01

    A spectrophotometric method for the determination of the fungicide captan has been developed based on its reaction with thiosemicarbazide. The absorbance was measured at 315 nm. The effects of the proportion of water, thiosemicarbazide concentration, pH and temperature on this reaction was studied to select the best chemical conditions. The calibration graph was obtained between 1.2 and 30 ppm and the detection limit is 0.5 ppm. The RSD (n = 10) was 1.34%. Possible interference of various pesticides was examined. The method was applied to the determination of captan in agrochemical formulations. Results agree well with the labelled values and also with results that were obtained by a polarographic method.

  9. Study on Rapid Determination of Bisphenol S by Ultraviolet Spectrophotometric Method in Plastic Products%紫外分光光度法快速检测塑料制品中的双酚S

    Institute of Scientific and Technical Information of China (English)

    王丽; 乐传俊; 王雯彬

    2015-01-01

    在碱性条件下,双酚S紫外吸收光谱的最强吸收峰发生红移,从257 nm移至293 nm,据此建立了简单、灵敏、快捷、选择性较好的测定双酚S的紫外分光光度法.研究了氨水用量、反应时间,反应温度的影响.结果表明:双酚S的最大吸收波长为293 nm,线性范围是0.6 mg/L~7.2 mg/L,相关系数r为0.997 3.这种方法简单快速,结果稳定准确,为塑料制品中双酚S的残留检测提供了新的试验方法.%Under alkaline conditions, the UV-Vis maximum absorption of bisphenol S exhibited bathochromic shift from 257 nm to 293 nm. Based on which, a simpler, quicker, more sensitive and more selective UV-spectrophotometric method to determine bisphenol S was established. The effects of the amount of ammonia water, reaction time, reaction temperature were investigated. The analysis showed that the maximum absorption wavelength of bisphenol S was 293 nm, the linear range was 0.6 mg/L-7.2 mg/L, and the correlation coefficients r was 0.997 3. The determination method was simple and rapid , and the results were accurate and stable as well, hence a new method for bisphenol S residues determination was provided in plastic products.

  10. Pilot Study on the Nano-Composites Coats of Radar Wave's Absorption

    Institute of Scientific and Technical Information of China (English)

    HU Chuan-xin; ZhANG Lei; GAN Ai-feng; LI Wan-zhi; LIANG Wen-ting; ZHANG Chen-jia

    2004-01-01

    This thesis mainly introduced the guiding principle and physical model of the research on the nano-composites coats of radar wave's absorption, and then studied the qualitative analysis of the performance ameliorating of radar wave's absorption composite coats. And on the basis of the optimum design of multilayer wave's absorption materials, two new kinds of radar wave's absorption composite coats have been made, which are composed of nano-composites hydroxyl iron powder and hollow micro-sphere. The research indicated that the surface-density of these two new composite coats is less than 3.5 Kg/m2.The coats' thickness is about 1 mm. And the waves absorption capability is above the level of 5 db, in the range of 3 ~ 18GHz. Therefore the wave's absorption performance of these two new coats is better than nano-crystalloid in low frequency area. The pilot study has proved that the nano-composites coat's performance of radar wave's absorption excels the ordinary radar wave's absorption coats, so it needs to be further studied.

  11. Studies of Arctic Middle Atmosphere Chemistry using Infrared Absorption Spectroscopy

    Science.gov (United States)

    Lindenmaier, Rodica

    The objective of this Ph.D. project is to investigate Arctic middle atmosphere chemistry using solar infrared absorption spectroscopy. These measurements were made at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut, which is operated by the Canadian Network for the Detection of Atmospheric Change (CANDAC). This research is part of the CANDAC/PEARL Arctic Middle Atmosphere Chemistry theme and aims to improve our understanding of the processes controlling the stratospheric ozone budget using measurements of the concentrations of stratospheric constituents. The instrument, a Bruker IFS 125HR Fourier transform infrared (FTIR) spectrometer, has been specifically designed for high-resolution measurements over a broad spectral range and has been used to measure reactive species, source gases, reservoirs, and dynamical tracers at PEARL since August 2006. The first part of this research focuses on the optimization of ozone retrievals, for which 22 microwindows were studied and compared. The spectral region from 1000 to 1005 cm-1 was found to be the most sensitive in both the stratosphere and troposphere, giving the highest number of independent pieces of information and the smallest total error for retrievals at Eureka. Similar studies were performed in coordination with the Network for the Detection of Atmospheric Composition Change for nine other species, with the goal of improving and harmonizing the retrieval parameters among all Infrared Working Group sites. Previous satellite validation exercises have identified the highly variable polar conditions of the spring period to be a challenge. In this work, comparisons between the 125HR and ACE-FTS (Atmospheric Chemistry Experiment-Fourier transform spectrometer) from 2007 to 2010 have been used to develop strict criteria that allow the ground and satellite-based instruments to be confidently compared. After applying these criteria, the differences between the two instruments were generally

  12. Contributions te the study of methods and factors affecting the spectrophotometric determination of boron traces with carmin uranium compounds; Contribucion al estudio del metodo y factores que afectan a la determinacion espectrofotometrica de trazas de boro con Carmin en compuestos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R.; Gasco Sanchez, L.

    1956-07-01

    The study of some factors affecting the spectrophotometric determination of boron traces with carmin is made; the influence of carmin from different origin, the stability of complex carmin-boric acid in relation with the sulphuric acid concentration, the interference produced by ion nitrate, and the ion uraline and light influence are discussed. (Author) 36 refs.

  13. STUDY ON EUROPEAN FUNDS ABSORPTION IN ROMANIA FOR MEASURE 313

    Directory of Open Access Journals (Sweden)

    Florentina D. MATEI

    2014-06-01

    Full Text Available In this paper we wish to highlight the main causes of regional disparities in Romania in terms of absorption of European funds through Measure 313: Encouragement of tourism activities. The post-accession of Romania shows a major deficiency in attracting funds from the European Union, this situation is generated, in particular, by the lack of a coherent long-term vision of the authorities, insufficient resources for co-financing projects, low administrative capacity at central and local level, lack of inter-institutional coordination, public-private partnerships failures and insufficient skilled human resources . We will analyze the number of projects approved and implemented in each region of Romania (2007-2013 to establish the real possibilities of expansion of rural tourism.

  14. In situ x-ray-absorption spectroscopy study of hydrogen absorption by nickel-magnesium thin films

    International Nuclear Information System (INIS)

    Structural and electronic properties of co-sputtered Ni-Mg thin films with varying Ni to Mg ratio were studied by in situ x-ray absorption spectroscopy in the Ni L-edge and Mg K-edge regions. Codeposition of the metals led to increased disorder and decreased coordination around Ni and Mg compared to pure metal films. Exposure of the metallic films to hydrogen resulted in formation of hydrides and increased disorder. The presence of hydrogen as a near neighbor around Mg caused a drastic reduction in the intensities of multiple scattering resonances at higher energies. The optical switching behavior and changes in the x-ray spectra varied with Ni to Mg atomic ratio. Pure Mg films with Pd overlayers were converted to MgH2: The H atoms occupy regular sites as in bulk MgH2. Although optical switching was slow in the absence of Ni, the amount of H2 absorption was large. Incorporation of Ni in Mg films led to an increase in the speed of optical switching but decreased maximum transparency. Significant shifts in the Ni L3 and L2 peaks are consistent with strong interaction with hydrogen in the mixed films

  15. Hydrodynamic and absorption studies of carbon dioxide absorption in aqueous amide solutions using a bubble column contactor

    Directory of Open Access Journals (Sweden)

    A. Blanco

    2013-12-01

    Full Text Available The present work analyses the carbon dioxide absorption process in aqueous n-alkylpyrrolidones solutions, from the point of view of hydrodynamic studies as well as mass transfer, using a bubble column contactor. An analysis of the influence of solute concentration and gas flow-rate is complemented by the study of the effect caused by the alkyl group on the hydrodynamics and mass transfer. The presence of this kind of substance produces a decrease in mass transfer rate, but on the basis of interfacial area and mass transfer coefficient values, ethyl-2-pyrrolidine (EP shows suitable characteristics to replace methyl-2-pyrrolidine (MP in gas separation processes due to its lower safety problems.

  16. Study on tannin–metal interaction in aqueous solution using spectrophotometric titration and micelle-mediated separation/atomic absorption spectrometry

    Science.gov (United States)

    Tannins, including hydrolysable and condensed tannins, are important secondary metabolites of vascular plants and are a major plant-derived carbon source in the environment. Due to the many phenolic hydroxyl groups characteristic of tannins, these compounds have been long been thought to play signi...

  17. Experimental studies on the influence of porosity on membrane absorption process

    Institute of Scientific and Technical Information of China (English)

    GAO Jian; REN Zhongqi; ZHANG Zeting; ZHANG Weidong

    2007-01-01

    Eight kinds of flat membranes with different micro-structures were chosen to carry out the membrane absorption experiments with CO2 and de-ionized water or According to experimental results,the membrane pores shape (stretched pore and cylinder pore) and membrane thickness do not affect the membrane absorption process,and the membrane porosity has only little influence on membrane absorption process for slow mass transfer system.However,the influence of porosity on the membrane absorption process became visible for fast mass transfer system.Moreover,the mass transfer behavior near the membrane surface on liquid side was studied.The results show that the influence of membrane porosity on mass transfer relates to flow condition,absorption system and distance between micro-pores,etc.

  18. SHARDS: Survey for High-z Absorption Red & Dead Sources

    OpenAIRE

    Pérez-González, P. G.; Cava, A; the SHARDS Team

    2012-01-01

    SHARDS, an ESO/GTC Large Program, is an ultra-deep (26.5 mag) spectro-photometric survey with GTC/OSIRIS designed to select and study massive passively evolving galaxies at z=1.0-2.3 in the GOODS-N field using a set of 24 medium-band filters (FWHM~17 nm) covering the 500-950 nm spectral range. Our observing strategy has been planned to detect, for z>1 sources, the prominent Mg absorption feature (at rest-frame ~280 nm), a distinctive, necessary, and sufficient feature of evolved stellar popul...

  19. Study on the interaction between fluoroquinolones and erythrosine by absorption, fluorescence and resonance Rayleigh scattering spectra and their application

    Science.gov (United States)

    Wang, Jian; Liu, Zhongfang; Liu, Jiangtao; Liu, Shaopu; Shen, Wei

    2008-03-01

    In pH 4.4-4.5 Britton-Robinson (BR) buffer solution, fluoroquinolone antibiotics (FLQs) including ciprofloxacin (CIP), norfloxacin (NOR), levofloxacin (LEV) and lomefloxacin (LOM) could react with erythrosine (Ery) to form 1:1 ion-association complexes, which not only resulted in the changes of the absorption spectra and the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS). These offered some indications of the determination of fluoroquinolone antibiotics by spectrophotometric, fluorescence and resonance Rayleigh scattering methods. The detection limits for fluoroquinolone antibiotics were in the range of 0.097-0.265 μg/mL for absorption methods, 0.022-0.100 μg/mL for fluorophotometry and 0.014-0.027 μg/mL for RRS method, respectively. Among them, the RRS method had the highest sensitivity. In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions and the properties of the analytical chemistry were investigated. The methods have been successfully applied to determination of some fluoroquinolone antibiotics in human urine samples and tablets. Taking CIP-Ery system as an example, the charge distribution, the enthalpy of formation and the mean polarizability were calculated by density function theory (DFT) method. In addition, the reasons for the enhancement of scattering spectra were discussed.

  20. SHARDS: AN OPTICAL SPECTRO-PHOTOMETRIC SURVEY OF DISTANT GALAXIES

    International Nuclear Information System (INIS)

    We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin2 at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R ∼ 50). The data reach an AB magnitude of 26.5 (at least at a 3σ level) with sub-arcsec seeing in all bands. SHARDS' main goal is to obtain accurate physical properties of intermediate- and high-z galaxies using well-sampled optical spectral energy distributions (SEDs) with sufficient spectral resolution to measure absorption and emission features, whose analysis will provide reliable stellar population and active galactic nucleus (AGN) parameters. Among the different populations of high-z galaxies, SHARDS' principal targets are massive quiescent galaxies at z > 1, whose existence is one of the major challenges facing current hierarchical models of galaxy formation. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures which should be applied to the GTC/OSIRIS data. An assessment of the SHARDS data quality is also performed. We present science demonstration results on the detection and study of emission-line galaxies (star-forming objects and AGNs) at z = 0-5. We also analyze the SEDs for a sample of 27 quiescent massive galaxies with spectroscopic redshifts in the range 1.0 < z ∼< 1.4. We discuss the improvements introduced by the SHARDS data set in the analysis of their star formation history and stellar properties. We discuss the systematics arising from the use of different stellar population libraries, typical in this kind of study. Averaging the results from the different libraries, we find that the UV-to-MIR SEDs of the massive quiescent galaxies at z = 1.0-1.4 are well described

  1. SHARDS: AN OPTICAL SPECTRO-PHOTOMETRIC SURVEY OF DISTANT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Gonzalez, Pablo G.; Cava, Antonio; Barro, Guillermo; Villar, Victor; Cardiel, Nicolas; Espino, Nestor; Gallego, Jesus [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Ferreras, Ignacio [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Rodriguez-Espinosa, Jose Miguel; Balcells, Marc; Cepa, Jordi [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Alonso-Herrero, Almudena [Instituto de Fisica de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander (Spain); Cenarro, Javier [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta 2, E-44001 Teruel (Spain); Charlot, Stephane [Institut d' Astrophysique de Paris, CNRS, Universite Pierre and Marie Curie, UMR 7095, 98bis bd Arago, F-75014 Paris (France); Cimatti, Andrea [Dipartimento di Astronomia, Universita degli Studi di Bologna, I-40127 Bologna (Italy); Conselice, Christopher J. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Daddi, Emmanuele; Elbaz, David [CEA, Laboratoire AIM, Irfu/SAp, F-91191 Gif-sur-Yvette (France); Donley, Jennifer [Los Alamos National Laboratory, Los Alamos, NM (United States); Gobat, R. [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d' Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); and others

    2013-01-01

    We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin{sup 2} at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R {approx} 50). The data reach an AB magnitude of 26.5 (at least at a 3{sigma} level) with sub-arcsec seeing in all bands. SHARDS' main goal is to obtain accurate physical properties of intermediate- and high-z galaxies using well-sampled optical spectral energy distributions (SEDs) with sufficient spectral resolution to measure absorption and emission features, whose analysis will provide reliable stellar population and active galactic nucleus (AGN) parameters. Among the different populations of high-z galaxies, SHARDS' principal targets are massive quiescent galaxies at z > 1, whose existence is one of the major challenges facing current hierarchical models of galaxy formation. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures which should be applied to the GTC/OSIRIS data. An assessment of the SHARDS data quality is also performed. We present science demonstration results on the detection and study of emission-line galaxies (star-forming objects and AGNs) at z = 0-5. We also analyze the SEDs for a sample of 27 quiescent massive galaxies with spectroscopic redshifts in the range 1.0 < z {approx}< 1.4. We discuss the improvements introduced by the SHARDS data set in the analysis of their star formation history and stellar properties. We discuss the systematics arising from the use of different stellar population libraries, typical in this kind of study. Averaging the results from the different libraries, we find that the UV-to-MIR SEDs of the massive quiescent galaxies at

  2. Cinchocaine hydrochloride determination by atomic absorption spectrometry and spectrophotometry.

    Science.gov (United States)

    Abdel-Ghani, Nour T; Youssef, Ahmed F A; Awady, Mohamed A

    2005-05-01

    Two sensitive spectrophotometric and atomic absorption spectrometric procedures have been developed for determination of cinchocaine hydrochloride (Cin.Cl) in pure form and in pharmaceutical formulation. The spectrophotometric method was based on formation of an insoluble colored ion-associate between the cited drug and tetrathiocyanatocobaltate (CoTC) or hexathiocyanatochromate (CrTC) which dissolved and extracted in an organic solvent. The optimal experimental conditions for quantitative extraction such as pH, concentration of the reagents and solvent were studied. Toluene and iso-butyl alcohol proved to be the most suitable solvents for quantitative extraction of Cin-CoTC and Cin-CrTC ion-associates with maximum absorbance at 620 and 555 nm, respectively. The optimum concentration ranges, molar absorptivities, Ringbom ranges and Sandell sensitivities were also evaluated. The atomic absorption spectrometric method is based on measuring of the excess cobalt or chromium in the aqueous solution, after precipitation of the drug, at 240.7 and 357.9 nm, respectively. Linear application ranges, characteristic masses and detection limits were 57.99-361.9, 50.40 and 4.22 microg ml(-1) of Cin.Cl, in case of CoTC, while 37.99-379.9, 18.94 and 0.81 microg ml(-1) in case of CrTC. PMID:15910814

  3. Cinchocaine hydrochloride determination by atomic absorption spectrometry and spectrophotometry.

    Science.gov (United States)

    Abdel-Ghani, Nour T; Youssef, Ahmed F A; Awady, Mohamed A

    2005-05-01

    Two sensitive spectrophotometric and atomic absorption spectrometric procedures have been developed for determination of cinchocaine hydrochloride (Cin.Cl) in pure form and in pharmaceutical formulation. The spectrophotometric method was based on formation of an insoluble colored ion-associate between the cited drug and tetrathiocyanatocobaltate (CoTC) or hexathiocyanatochromate (CrTC) which dissolved and extracted in an organic solvent. The optimal experimental conditions for quantitative extraction such as pH, concentration of the reagents and solvent were studied. Toluene and iso-butyl alcohol proved to be the most suitable solvents for quantitative extraction of Cin-CoTC and Cin-CrTC ion-associates with maximum absorbance at 620 and 555 nm, respectively. The optimum concentration ranges, molar absorptivities, Ringbom ranges and Sandell sensitivities were also evaluated. The atomic absorption spectrometric method is based on measuring of the excess cobalt or chromium in the aqueous solution, after precipitation of the drug, at 240.7 and 357.9 nm, respectively. Linear application ranges, characteristic masses and detection limits were 57.99-361.9, 50.40 and 4.22 microg ml(-1) of Cin.Cl, in case of CoTC, while 37.99-379.9, 18.94 and 0.81 microg ml(-1) in case of CrTC.

  4. A spectrophotometric and thermodynamic study of the charge-transfer complexes of iodine with 2-aminomethyl-15-crown-5 in chloroform and 1,2-dichloroethane solutions.

    Science.gov (United States)

    Hasani, Masoumeh; Akbari, Sakineh

    2007-05-01

    Interaction of 2-aminomethyl-15-crown-5 (AM15C5) with iodine has been investigated spectrophotometrically in chloroform and 1,2-dichloroethane (1,2-DCE) solutions. The observed time dependence of the charge-transfer band and subsequent formation of I(3)(-) in solution were related to the slow transformation of the initially formed 1:1 AM15C5.I(2) outer complex to an inner electron donor-acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion. The pseudo-first-order rate constants were evaluated from the absorbance- and conductivity-time data. The stoichiometry and formation constants of the resulting EDA complexes have also been determined. Thermodynamic parameters, Delta H degrees and Delta S degrees , of the complexes have been determined from the temperature dependence of stability constants by Van't Hoff equation. The results indicate that iodine complexes of AM15C5 in both solvents are enthalpy stabilized but entropy destabilized. The influence of solvent properties on the kinetics and stability of the resulting charge-transfer complexes are discussed.

  5. Structural studies using X-ray absorption and scattering techniques

    International Nuclear Information System (INIS)

    The thesis presents extended X-ray absorption fine structure, EXAFS, and large angle X-ray scattering, LAXS, techniques; instrumentation, data collection and reduction, and applications. These techniques have been used to determine the structures of magnesium halides and organomagnesium halides in diethyl ether and tetrahydrofuran solution. The iodides were used for the LAXS measurements and Br K edge EXAFS data were collected for the corresponding bromides. Two different complexes are present in the diethyl ether solution of magnesium iodide; a polymeric chain-type structure where magnesium is tetrahedrally coordinated, as well as dimeric complex with octahedrally coordinated magnesium. Solvated MgI+ is the dominating species in tetrahydrofuran solution. The organomagnesium halides are present in diethyl ether solution as both solvated monomeric and dimeric complexes. Magnesium coordinates a halide ion, an alkyl or aryl group and four solvent molecules octahedrally in the monomeric complex. In the dimeric complex magnesium is octahedrally coordinated by two bridging halide ions, an alkyl or aryl group and three solvent molecules. The distribution of monomeric and dimeric complexes in various solutions are given by a dimerisation constant, Kdl. The results indicate that the Schlenk equilibrium is present in these solutions, however, in an extended form. In diethyl ether solution, where MgX2 does not dissociate, no MgX2 complex and thereby no Schlenk equilibrium has been observed. In tetrahydrofuran solution MgI2 has dissociated into mainly MgI+ and I-. This indicates that the concentration of MgI2 is low and that the Schlenk equilibrium should be expanded even further to include the dissociation equilibrium of the magnesium halide. In the thesis Fe K edge EXAFS data collected for the semireduced form of protein A of methane monooxygenase from Methylococcus capsulatus, are also presented. (139 refs.)

  6. Experimental Study on the Energy Absorption Properties of MWK Reinforced Composites

    Institute of Scientific and Technical Information of China (English)

    ZHOU Rong-xing; LI Wei; CHEN Nan-liang; FENG Xun-wei

    2002-01-01

    The energy absorption properties of MWK fabric reinforced composite plates were studied. Low velocity and low energy impact experiments were carried out for MWK fabric reinforced Glassfibre/Epoxy composite plate, by setting up a drop weight impact test system.Using this system, the drop weight velocity during impacting was obtained and recorded by transducer and corresponding signal processing system. Based on the velocity record, the impact energy and dissipated impact energy (energy absorption) were obtained. The influences of structure parameters of MWK on the impact behavior and energy absorption properties were then investigated.

  7. Study on NO2 absorption by ascorbic acid and various chemicals

    Institute of Scientific and Technical Information of China (English)

    LI Wei; WU Cheng-zhi; FANG He-liang; SHI Yao; LEI Le-cheng

    2006-01-01

    Study on NO2 absorption aimed at seeking a better NO2 absorption chemical at pH 4.5~7.0 for application to existing wet flue gas desulfurization (FGD). The results from the double-stirred reactor indicated thru ascorbic acid has very high absorption rate at this pH range. The rate constant of ascorbic acid reaction with NO2 (0~1000× 10-6 mol/mol) is about 3.54× 106 mol/(L.s)at pH 5.4~6.5 at 55 ℃.

  8. Evaluation of the color durability of acrylic resin veneer materials after immersion in common beverages at different time intervals: A spectrophotometric study

    Directory of Open Access Journals (Sweden)

    Shivani Kohli

    2015-06-01

    Full Text Available Background: Proper function, esthetics, and cost are the prime factors to be considered while selecting bridge veneering materials. The purpose of the study is to evaluate color durability of acrylic veneer materials after immersion in common beverages at different time intervals. Methods: Spectrophotometer was used for taking color measurements based on the transmission of light through the specimens made of the selected materials which were Tooth moulding powder (DPI and Acrylux (Ruthinium. Thirty specimens of standardized dimensions were prepared from each material. The specimens were divided into three groups of 10 each. One group of each material was immersed in tea (TajMahal and another group of each material in cola (Pepsi as the staining solutions. The remaining group of 10 from each material served as control and was stored in distilled water. Color measurements were obtained pre-immersion, and after 1, 15, and 30 days of immersion. Results: Tooth moulding powder displayed better color durability than Acrylux over the 1 month immersion period in both staining solutions. Tea resulted in more discoloration compared to cola (Pepsi. Conclusion: The difference in the color durability of Acrylux and Tooth moulding powder may be attributed to the differences in the composition of tested resin veneering materials, i.e. their polar properties, which contribute to the absorption of staining solution, and the different brands and the strengths of the solutions.

  9. Spectrophotometric and Refractometric Determination of Total Protein in Avian Plasma

    Directory of Open Access Journals (Sweden)

    Rodica Căpriță

    2013-10-01

    Full Text Available The aim of this study was to compare the total protein values obtained in heparin plasma of chickens by a spectrophotometric technique (biuret method, and the values obtained on the same day in the same samples by refractometry. The results obtained by refractometry (average value 2.638±0.153g% were higher than those obtained by the spectrophotometric method (average value 2.441±0.181g%. There was a low correlation (r = 0.6709 between the total protein values, determined with both methods. Protein is the major determinant of plasma refractive index, but glucose contributes too. The refractometric method is not recommended in chickens for the determination of total protein, because avian blood glucose concentration averages about twice than in mammalian blood.

  10. Spectroscopy of α,ω-dithienyl polyenes: evidence for two-photon absorption states from fluorescence studies

    Science.gov (United States)

    Natarajan, Lalgudi V.; Kirkpatrick, Sean M.; Sutherland, Richard L.; Sowards, Laura A.; Spangler, Charles W.; Fleitz, Paul A.; Cooper, Thomas M.

    1998-10-01

    The photophysics of a series (alpha) ,(omega) -dithienyl polyenes was studied. Both one photon excited fluorescence and fluorescence originating from two photon absorption states were investigated. There is strong evidence of two photon absorption from fluorescence studies in agreement with our earlier studies involving nonlinear absorption.

  11. [Study on intestinal absorption features of oligosaccharides in Morinda officinalis How. with sigle-pass perfusion].

    Science.gov (United States)

    Deng, Shao-Dong; Zhang, Peng; Lin, Li; Xiao, Feng-Xia; Lin, Jing-Ran

    2015-01-01

    To study the in situ intestinal absorption of five oligosaccharides contained in Morinda officinalis How. (sucrose, kestose, nystose, 1F-Fructofuranosyinystose and Bajijiasu). The absorption of the five oligosaccharides in small intestine (duodenum, jejunum and ileum) and colon of rats and their contents were investigated by using in situ single-pass perfusion model and HPLC-ELSD. The effects of drug concentration, pH in perfusate and P-glycoprotein inhibitor on the intestinal absorption were investigated to define the intestinal absorption mechanism of the five oligosaccharides in rats. According to the results, all of the five oligosaccharides were absorbed in the whole intestine, and their absorption rates were affected by the pH of the perfusion solution, drug concentration and intestinal segments. Verapamil Hydrochloride could significantly increase the absorptive amount of sucrose and Bajijiasu, suggesting sucrose and Bajijiasu are P-gp's substrate. The five oligosaccharides are absorbed mainly through passive diffusion in the intestinal segments, without saturated absorption. They are absorbed well in all intestines and mainly in duodenum and jejunum.

  12. [Study on intestinal absorption features of oligosaccharides in Morinda officinalis How. with sigle-pass perfusion].

    Science.gov (United States)

    Deng, Shao-Dong; Zhang, Peng; Lin, Li; Xiao, Feng-Xia; Lin, Jing-Ran

    2015-01-01

    To study the in situ intestinal absorption of five oligosaccharides contained in Morinda officinalis How. (sucrose, kestose, nystose, 1F-Fructofuranosyinystose and Bajijiasu). The absorption of the five oligosaccharides in small intestine (duodenum, jejunum and ileum) and colon of rats and their contents were investigated by using in situ single-pass perfusion model and HPLC-ELSD. The effects of drug concentration, pH in perfusate and P-glycoprotein inhibitor on the intestinal absorption were investigated to define the intestinal absorption mechanism of the five oligosaccharides in rats. According to the results, all of the five oligosaccharides were absorbed in the whole intestine, and their absorption rates were affected by the pH of the perfusion solution, drug concentration and intestinal segments. Verapamil Hydrochloride could significantly increase the absorptive amount of sucrose and Bajijiasu, suggesting sucrose and Bajijiasu are P-gp's substrate. The five oligosaccharides are absorbed mainly through passive diffusion in the intestinal segments, without saturated absorption. They are absorbed well in all intestines and mainly in duodenum and jejunum. PMID:25993803

  13. Simultaneous spectrophotometric determination of cobalt,copper and nickel using 1-(2-thiazolylazo)-2-naphthol by chemometrics methods

    Institute of Scientific and Technical Information of China (English)

    Ali Niazi; Ateesa Yazdanipour

    2008-01-01

    The simultaneous determination of cobalt,copper and nickel using 1-(2-thiazolylazo)-2-naphthol (first figure of this article) by spectrophotometric method is a difficult problem in analytical chemistry,due to spectral interferences.By multivariate calibration methods,such as partial least squares (PLS) regression,it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range.Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis.OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method.In this study,the calibration model is based on absorption spectra in the 550-750-nm range for 21 different mixtures of cobalt,copper and nickel.Calibration matrices were formed from samples containing 0.05-1.05,0.05-1.30 and 0.05-0.80 μg mL-1 for cobalt,copper and nickel,respectively.The root mean square error of prediction (RMSEP) for cobalt,copper and nickel with OSC and without OSC were 0.007,0.008,0.011 and 0.031,0.037,0.032 μg mL-1,respectively.This procedure allows the simultaneous determination of cobalt,copper and nickel in synthetic and real samples and good reliability of the determination was proved.

  14. Studies concerning thermodynamics and kinetics of the absorption of halogenated hydrocarbons relevant to environment

    International Nuclear Information System (INIS)

    In the context of the research project the scrubbing of air contaminated by peculiar volatile organic compounds was investigated using the absorption technique by means of high boiling organics as washing liquids. Eight chlorinated hydrocarbons well known from technical processes were chosen to be representative for the volatile organic compounds. Eleven absorption media were selected on the basis of their physical properties. For the determination of the solubility data of the absorption media due to chlorinated hydrocarbons, nitrogen as well as a mixture of nitrogen and oxygen were used as carrier gas. The influence of the dipole moment of the absorption media on the amount of solubility - expressed as enrichment factor - was studied, too. Concerning the technical application, the thermostability and the stability against diluted inorganic acids were studied as well. (orig.). 56 figs., 8 tabs., 63 refs

  15. Stratum corneum damage and ex vivo porcine skin water absorption - a pilot study

    DEFF Research Database (Denmark)

    Duch Lynggaard, C; Bang Knudsen, D; Jemec, G B E

    2009-01-01

    A simple ex vivo screening technique would be of interest for mass screening of substances for potential barrier disruptive qualities. Ex vivo water absorption as a marker of skin barrier integrity was studied on pig ear skin. Skin water absorption was quantified by weighing and weight changes were...... found to reflect prehydration barrier damage. It is suggested that this simple model may be elaborated to provide a rapid, economical screening tool for potential skin irritants....

  16. Polarization dependent interface properties of ferroelectric Schottky barriers studied by soft X-ray absorption spectroscopy

    OpenAIRE

    Kohlstedt, H.; Petraru, A.; Denlinger, M. Meier J.; Guo, J.; Wanli, Y.; A. Scholl; Freelon, B.; Schneller, T.; Waser, R.; Yu, P; Ramesh, R.; Learmonth, T.; Glans, P.-A.; Smith, K. E.

    2008-01-01

    We applied soft X-ray absorption spectroscopy to study the Ti L-edge in ferroelectric capacitors using a modified total electron yield method. The inner photo currents and the X-ray absorption spectra were polarization state dependent. The results are explained on the basis of photo electric effects and the inner potential in the ferroelectric capacitors as a result of back-to-back Schottky barriers superimposed by the potential due to the depolarization field. In general, the presented metho...

  17. Analytical and Experimental Study of X-ray Absorption Coefficients of Material by Abel's Inversion

    OpenAIRE

    S. J. Han

    2009-01-01

    The hard x-ray gamma-ray absorption by cylindrically symmetric U-238 test objects is studied by means of gamma-ray transmission measurements. To make a precise comparison between the theoretically modelled values and the absorption coefficients calculated from the experimental data, we have developed a highly accurate numerical code based on a new solution of Abel's integral equation. It is shown that progressive filtering, surface reflections by Compton scattering, and the enhanced backscatt...

  18. Estimation of citicoline sodium in tablets by difference spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Sagar Suman Panda

    2013-01-01

    Full Text Available Aim: The present work deals with development and validation of a novel, precise, and accurate spectrophotometric method for the estimation of citicoline sodium (CTS in tablets. This spectrophotometric method is based on the principle that CTS shows two different forms that differs in the absorption spectra in basic and acidic medium. Materials and Methods: The present work was being carried out on Shimadzu 1800 Double Beam UV-visible spectrophotometer. Difference spectra were generated using 10 mm quartz cells over the range of 200-400 nm. Solvents used were 0.1 M NaOH and 0.1 M HCl. Results: The maxima and minima in the difference spectra of CTS were found to be 239 nm and 283 nm, respectively. Amplitude was calculated from the maxima and minima of spectrum. The drug follows linearity in the range of 1-50 μ/ml (R 2 = 0.999. The average % recovery from the tablet formulation was found to be 98.47%. The method was validated as per International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use: ICH Q2(R1 Validation of Analytical Procedures: Text and Methodology guidelines. Conclusion: This method is simple and inexpensive. Hence it can be applied for determination of the drug in pharmaceutical dosage forms.

  19. Two novel spectrophotometric methods for determinat ion of ternary mixture used as antihypertensive therapy in combined tablet dosage formulation

    OpenAIRE

    Trupti Solanki; Jenee Christian; Kalpana Patel; Purvi Shah; Tejal Gandhi

    2015-01-01

    Aim: To develop and validate two novel spectrophotometric methods for the simultaneous determination of ternary mixture of Olmesartan medoxomil, Amlodipine besylate and Hydrochlorothiazide. Methods: The proposed methods, successive ratio derivative method and double divisor method involved treatment of normal absorption spectra of ternary mixture in UV probe software for the simultaneous determination of Olmesartan medoxomil, Amlodipine besylate and Hydrochlorothiazide in bulk and tablet ...

  20. Spectrophotometric Assay of Phenylephrine Hydrochloride Using 4-Aminoantipyrine and Copper (II

    Directory of Open Access Journals (Sweden)

    Theia'a N. Al-Sabha

    2010-06-01

    Full Text Available A new spectrophotometric method is proposed for determination of phenylephrine hydrochloride. The method is based on the coupling of 4-aminoantipyrine (4-AAP with phenylephrine hydrochloride (PEH to give a new ligand that reacts with copper (II in the presence of sodium tetraborate buffer solution of pH 9.00 at 50 °C to give an intense red colored chelate having maximum absorption at 480 nm. The optimization of the experimental conditions is described. The method has been used for the determination of 2.0–50.0 μg/ml of PEH. The molar absorptivity is 5.34×103 L.mol.-1cm.-1 and the accuracy of the method is achieved by the value of average recovery (101.28 % and the precision is supported by relative standard deviation (RSD=1.25 % values. The results of the method was compared with those of the standard method. The interference of excipients was studied. The mechanism of the chemical reaction has been proposed. The proposed method was successfully applied for the determination of the PEH in pharmaceutical syrup formulations.

  1. Spectrophotometric Determination of Doripenem, Ertapenem in Bulk and Injection Formulations by F-C Reagent

    Directory of Open Access Journals (Sweden)

    K. Raghu Babu

    2013-10-01

    Full Text Available Two simple and cost effective spectrophotometric methods were described for the determination of Doripenem and Ertapenem in pure form and in pharmaceutical formulations. The method is based on the formation of blue colored chromogen when the drug reacts with Folin-Ciocalteu (F-C reagent in alkaline medium. The colored species has an absorption maximum at 725 nm for Doripenem (Method A; 848 nm for Ertapenem (Method B and obeys beer’s law in the concentration range 0.02-0.1 mg/mL for both Doripenem and Ertapenem. The apparent molar absorptivities were 1.26×10-5, 7.86×10-6 and sandell’s sensitivity was 6×10-4 respectively for Doripenem and Ertapenem. The slopes were 0.3371 ± 0.01245, 0.2611 ± 0.004327 and intercept of the equation of the regression line are 0.02857 ± 0.01885, -0.008095 ± 0.006550 for Doripenem and Ertapenem respectively. The optimum experimental parameters for the reaction have been studied and the validity of the described procedure was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed method was successfully applied for the determination of Doripenem and Ertapenem in pharmaceutical formulations.

  2. A study of energy absorption rate in a quantum dot and metallic nanosphere hybrid system

    International Nuclear Information System (INIS)

    We have studied energy absorption rate in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. We applied a control field to induce dipole moments in the quantum dot and the metal nanosphere, and monitored the energy absorption using a probe field. These external fields induce dipole moments in the metal nanosphere and the quantum dot, and these two structures interact with one another via the dipole–dipole interaction. The density matrix method was used to evaluate the absorption, indicating that it can be shifted by moving the metal nanosphere close to the quantum dot. Also, absorption efficiency can either be quenched or enhanced by the addition of a metal nanosphere. This hybrid system can be used to create ultrafast switching and sensing nanodevices. (paper)

  3. Studying Turbulence from Doppler-broadened Absorption Lines: Statistics of Logarithms of Intensity

    CERN Document Server

    Lazarian, A

    2008-01-01

    We continue our work on developing techniques for studying turbulence with spectroscopic data. We show that Doppler-broadened absorption spectral lines, in particularly, saturated absorption lines, can be used within the framework of the earlier-introduced technique termed the Velocity Coordinate spectrum (VCS). The VCS relates the statistics of fluctuations along the velocity coordinate to the statistics of turbulence, thus it does not require spatial coverage by sampling directions in the plane of the sky. We consider lines with different degree of absorption and show that for lines of optical depth less than one, our earlier treatment of the VCS developed for spectral emission lines is applicable, if the optical depth is used instead of intensity. This amounts to correlating the logarithms of absorbed intensities. For larger optical depths and saturated absorption lines, we show, that the amount of information that one can use is, inevitably, limited by noise. In practical terms, this means that only wings...

  4. Simultaneous Spectrophotometric Determination of Four Components including Acetaminophen by Taget Factor Analysis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    UV Spectrophotometric Target Factor Analysis (TFA) was used for the simultaneous determination of four components (acetaminophen, guuaifenesin, caffeine, Chlorphenamine maleate) in cough syrup. The computer program of TFA is based on VC++ language. The difficulty of overlapping of absorption spectra of four compounds was overcome by this procedure. The experimental results show that the average recovery of each component is all in the range from 98.9% to 106.8% and each component obtains satisfactory results without any pre-separation.

  5. Evaluation of chromium concentration in cattle feces using different acid digestion and spectrophotometric quantification techniques

    OpenAIRE

    N.K.P. Souza; E. Detmann; D. S. Pina; Valadares Filho, S. C.; C.B. Sampaio; A.C. Queiroz; C.M. Veloso

    2013-01-01

    The objective of this work was to evaluate combinations between acid digestion techniques and spectrophotometric quantification to measure chromium concentration in cattle feces. Digestion techniques were evaluated based on the use of nitric and perchloric acids, sulfuric and perchloric acids, and phosphoric acid. The chromium quantification in the solutions was performed by colorimetry and by atomic absorption spectrophotometry (AAS). When AAS was used, the addition of calcium chloride to th...

  6. A study of sound absorption by street canyon boundaries and asphalt rubber concrete pavement

    Science.gov (United States)

    Drysdale, Graeme Robert

    A sound field model, based on a classical diffusion equation, is extended to account for sound absorption in a diffusion parameter used to model sound energy in a narrow street canyon. The model accounts for a single sound absorption coefficient, separate accommodation coefficients and a combination of separate absorption and accommodation coefficients from parallel canyon walls. The new expressions are compared to the original formula through numerical simulations to reveal the effect of absorption on sound diffusion. The newly established analytical formulae demonstrate satisfactory agreement with their predecessor under perfect reflection. As well, the influence of the extended diffusion parameter on normalized sound pressure levels in a narrow street canyon is in agreement with experimental data. The diffusion parameters are used to model sound energy density in a street canyon as a function of the sound absorption coefficient of the street canyon walls. The acoustic and material properties of conventional and asphalt rubber concrete (ARC) pavement are also studied to assess how the crumb rubber content influences sound absorption in street canyons. The porosity and absolute permeability of compacted specimens of asphalt rubber concrete are measured and compared to their normal and random incidence sound absorption coefficients as a function of crumb rubber content in the modified binder. Nonlinear trends are found between the sound absorption coefficients, porosity and absolute permeability of the compacted specimens and the percentage of crumb rubber in the modified binders. The cross-sectional areas of the air voids on the surfaces of the compacted specimens are measured using digital image processing techniques and a linear relationship is obtained between the average void area and crumb rubber content. The measured material properties are used to construct an empirical formula relating the average porosity, normal incidence noise reduction coefficients and

  7. Studies on different iron source absorption by in situ ligated intestinal loops of broilers.

    Science.gov (United States)

    Jia, Y F; Jiang, M M; Sun, J; Shi, R B; Liu, D S

    2015-02-01

    The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

  8. QSAR Study and VolSurf Characterization of Human Intestinal Absorption of Druge

    Institute of Scientific and Technical Information of China (English)

    胡桂香; 商志才; 等

    2003-01-01

    The prediction of human intestinal absorption is a major goal in the design,optimization,and selection of candidates for the develoment of oral drugs.In this study,a computerized method(VolSurf with GRID) was used as a novel tool for predicting human intestinal absorption of test compound,and for determining the critical molecular properties needed for human intestinal absorption.The tested molecules consisted of 20 diverse drug-like compounds.Partial least squares(PLS) discriminant analysis was used to correlate the experimental data with the theoretical molecular properties of human intestinal absorption.A good correlation(r2=0.95,q2=0.86) between the molecular modeling results and the experimental data demonstrated that human intestinal absorption could be predicted from the three-dimensional(3D) molecular structure of a compound .Favorable structureal properties identified for the potent intestinal absorption of drugs included strong imbalance between the center of mass of a molecule and the barycentre of its hydrophilic and hydrophobic regions and a definitive hydrophobic region as well as less hydrogen bonding donors and acceptors in the molecule.

  9. Spectrophotometric determination of triclosan in personal care products

    Science.gov (United States)

    Lu, Huihui; Ma, Hongbing; Tao, Guanhong

    2009-09-01

    A spectrophotometric method for the determination of triclosan in personal care products was proposed. It was based on the reaction of sodium nitrite with p-sulfanilic acid in an acidic medium to form diazonium ion, with which triclosan further formed an azo compound in an alkaline medium. The resulting yellow colored product has a maximum absorption at 452 nm. A good linear relationship ( r = 0.9999) was obtained in the range of 0-30 mg L -1 triclosan. A detection limit of 0.079 g L -1 was achieved and the relative standard deviation was 0.24% ( n = 11) at 14 mg L -1 triclosan. The proposed method has been applied to the analyses of triclosan in several personal care products and the results were in good agreement with those obtained by high-performance liquid chromatography.

  10. Spectrophotometric determination of nitrite in simulated Purex Process solutions

    International Nuclear Information System (INIS)

    A spectrophotometric method for nitrite determination in simulated Purex Process solutions is presented, utilizing the Griess reagent for the formation of the coloured azocompound with an absorption maximum at 525 nm. Molar absortivity was 36,262 and the sensitivity of the method 10-6M for nitrite. The calibration curve is linear in the range of 2 to 30μg NO-2/25 ml in cells of 1 cm optical path. The method can be used in the presence of uranium up to limits of an U/NO-2 ratio of 150. Test solutions were prepared to simulate composition and concentrations as obtained by irradiating standard fuel with a neutro flux of 3.2 x 1013 n.s-1.cm-2, with a burn-up value of 33,000 Mwd/T and cooling time of two years. Nitrite determinations in these solutions were accurate within limits of 5%. (Author)

  11. Spectrophotometric estimation of roxithromycin in tablet dosage forms

    Directory of Open Access Journals (Sweden)

    Suhagia B

    2006-01-01

    Full Text Available A simple and sensitive spectrophotometric method has been developed for determination of roxithromycin in its pharmaceutical dosage forms. In the proposed method, roxithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone in the presence of ammonium acetate to give a yellow-coloured chromogen with absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml with regression coefficient of 0.9987. No significant difference was found between the proposed method and the reported method when two-tailed t-tests are applied. Various reaction parameters, such as concentration of potassium permanganate and reagent, time required for oxidation and maximum colour intensity, were optimized. The method was validated and can be used successfully to assay roxithromycin in its pharmaceutical dosage form, viz, tablets.

  12. Determination of Azithromycin in pharmaceutical dosage forms by Spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Suhagia B

    2006-01-01

    Full Text Available A simple and sensitive spectrophotometric method has been developed for determination of azithromycin in its pharmaceutical dosage forms. In the proposed method, azithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone, in the presence of ammonium acetate. A yellow coloured chromogen was obtained, having an absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml, with regression coefficient of 0.9978. Various reaction parameters such as concentration of potassium permanganate and reagent, time required for oxidation, and maximum colour intensity were optimized. The method was validated, and can be used successfully to assay azithromycin in its pharmaceutical dosage forms viz. tablets, capsules, and injections.

  13. DECal: A Spectrophotometric Calibration System For DECam

    CERN Document Server

    Marshall, J L; DePoy, D L; Prochaska, Travis; Allen, Richard; Behm, Tyler W; Martin, Emily C; Veal, Brannon; Villanueva,, Steven; Williams, Patrick; Wise, Jason

    2013-01-01

    DECal is a new calibration system for the CTIO 4 m Blanco telescope. It is currently being installed as part of the Dark Energy Survey and will provide both broadband flat fields and narrowband (about 1 nm bandwidth) spectrophotometric calibration for the new Dark Energy Camera (DECam). Both of these systems share a new Lambertian flat field screen. The broadband flat field system uses LEDs to illuminate each photometric filter. The spectrophotometric calibration system consists of a monochromator-based tunable light source that is projected onto the flat field screen using a custom line-to-spot fiber bundle and an engineered diffuser. Several calibrated photodiodes positioned along the beam monitor the telescope throughput as a function of wavelength. This system will measure the wavelength-dependent instrumental response function of the total telescope+instrument system in the range 300 < lambda < 1100nm. The spectrophotometric calibration will be performed regularly (roughly once per month) to determ...

  14. Photochemical and thermal degradation of a naturally occurring dye used in artistic painting. A chromatographic, spectrophotometric and fluorimetric study on saffron

    OpenAIRE

    Vida Vickackaite; Aldo Romani; Danilo Pannacci; Gianna Favaro

    2004-01-01

    Saffron is a yellow substance which is extracted from the stigmas of Crocus sativus L. and is used in painting, cooking and medicine. In this paper six components (trans and cis crocins) with carotenoid structures were separated from natural saffron by HPLC and were characterised by their absorption and emission spectra. Photochemical and thermal processes which degrade the dye were also investigated. The effect of light promoted the cis ⇄ trans isomerization, while the thermal ef...

  15. Simple UV spectrophotometric assay of Mefenamic acid

    Directory of Open Access Journals (Sweden)

    Dr. Safila Naveed

    2014-07-01

    Full Text Available Mefenamic acid belongs to non-steroidal antiinflammatory drugs (NSAID.. It is being used widely for the treatment of analgesia. It is also used as antirheumatic and antipyretic drug. Our aim of study is to develop a efficient least time consuming and simple spectrophotometric method for the assay of mefenamic acid. Comparision of assay of three different brands of mefenamic acid (mefnac,ponstan,dolar available in public medical store of Karachi, Pakistan has also been done. The assay is based on the ultraviolet UV absorbance maxima at about 288nm wavelength of mefenamic acid, water is used as solvent. A sample of drug was dissolved in water to produce a solution containing mefenamic acid. Similarly, a sample of ground tablets of different brand were dissolved in water and various dilutions were made. The absorbance of sample preparation was measured at 288nm against the solvent blank and the assay was determined by comparing with the absorbance of available brand. Our results reveals that among all the three brands of mefenamic acid (mefnac,ponstan,dolar rosulin and rovista shows highest percentage assay 107.5%. xplended and rosubar shows percent assay of 106.25% and 103.75% while rovactor shows lowest value for percentage assay 98.75%.

  16. Ultraviolet spectrophotometric determination of tantalum with pyrogallol

    Science.gov (United States)

    Dinnin, J.I.

    1953-01-01

    In a search for a more rapid method for the determination of tantalum in rocks and minerals, an intensive study was made of the tantalum-pyrogallol reaction recommended by Platanov and Krivoshlikov, and a better modified spectrophotometric procedure is given. The improved method consists in measuring the absorbancy of the tantalum-pyrogallol complex at 325 m?? in 4N hydrochloric acid and a fixed concentration (0.0175M) of ammonium oxalate. Beer's law is followed for the concentration range up to 40 ?? per ml. Sensitivity in terms of molar absorbancy index is 4775. Most interferences are additive in character and readily correctable. Separations or major corrections are required in the presence of significant amounts of molybdenum, tungsten, antimony, and uranium. The method has been successfully applied to three ores previously analyzed by gravimetric techniques. The method affords greater speed, sensitivity, and reproducibility in the determination of tantalum in rocks and minerals. A more reliable technique for preparing standard solutions of tantalum has been developed.

  17. Spectrophotometric study of the reaction mechanism between DDQ as π-acceptor and potassium iodate and flucloxacillin and dicloxacillin drugs and their determination in pure and in dosage forms

    Science.gov (United States)

    Mohamed, Gehad G.; Nour El-Dien, F. A.; Farag, Eman U.

    2006-09-01

    Two simple and accurate spectrophotometric methods are presented for the determination of β-lactam drugs, flucloxacillin (Fluclox) and dicloxacillin (Diclox), in pure and in different pharmaceutical preparations. The charge transfer (CT) reactions between Fluclox and Diclox as electron donors and 2,3-dichloro-5,6-dicyano- p-benzoquinone (DDQ) π-acceptor and potassium iodate via oxidation reduction reaction where the highly coloured complex species or the liberated iodine have been spectrophotometrically studied. The optimum experimental conditions have been studied carefully. Beer's law is obeyed over the concentration range of 2-450 μg ml -1 for Fluclox and 10-450 μg ml -1 for Diclox using DDQ reagent and at 50-550 μg ml -1 for Fluclox and 50-560 μg ml -1 for Diclox using iodate method, respectively. For more accurate results, Ringbom optimum concentration range is calculated and found to be 6-450 and 15-450 μg ml -1 for Fluclox and Diclox using DDQ, respectively, and 65-550 and 63-560 μg ml -1 for Fluclox and Diclox using iodine, respectively. The Sandell sensitivity is found to be 0.018 and 0.011 μg cm -2 for DDQ method and 0.013 and 0.011 μg cm -2 for iodate method for Fluclox and Diclox, respectively, which indicates the high sensitivity of both methods. Standard deviation (S.D. = 0.01-0.80 and 0.07-0.98) and relative standard deviation (R.S.D. = 0.13-0.44 and 0.11-0.82%) ( n = 5) for DDQ and iodate methods, respectively, refer to the high accuracy and precision of the proposed methods. These results are also confirmed by between-day precision of percent recovery of 99.87-100.2 and 99.90-100% for Fluclox and Diclox by DDQ method and 99.88-100.1 and 99.30-100.2% for Fluclox and Diclox by iodate method, respectively. These data are comparable to those obtained by British and American pharmacopoeias assay for the determination of Fluclox and Diclox in raw materials and in pharmaceutical preparations.

  18. Novel spectrophotometric methods for simultaneous determination of Amlodipine, Valsartan and Hydrochlorothiazide in their ternary mixture

    Science.gov (United States)

    Lotfy, Hayam M.; Hegazy, Maha A.; Mowaka, Shereen; Mohamed, Ekram Hany

    2015-04-01

    This work represents a comparative study of two smart spectrophotometric techniques namely; successive resolution and progressive resolution for the simultaneous determination of ternary mixtures of Amlodipine (AML), Hydrochlorothiazide (HCT) and Valsartan (VAL) without prior separation steps. These techniques consist of several consecutive steps utilizing zero and/or ratio and/or derivative spectra. By applying successive spectrum subtraction coupled with constant multiplication method, the proposed drugs were obtained in their zero order absorption spectra and determined at their maxima 237.6 nm, 270.5 nm and 250 nm for AML, HCT and VAL, respectively; while by applying successive derivative subtraction they were obtained in their first derivative spectra and determined at P230.8-246, P261.4-278.2, P233.7-246.8 for AML, HCT and VAL respectively. While in the progressive resolution, the concentrations of the components were determined progressively from the same zero order absorption spectrum using absorbance subtraction coupled with absorptivity factor methods or from the same ratio spectrum using only one divisor via amplitude modulation method can be used for the determination of ternary mixtures using only one divisor where the concentrations of the components are determined progressively. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. Moreover comparative study between spectrum addition technique as a novel enrichment technique and a well established one namely spiking technique was adopted for the analysis of pharmaceutical formulations containing low concentration of AML. The methods were validated as per ICH guidelines where accuracy, precision and specificity were found to be within their acceptable limits. The results obtained from the proposed methods were statistically compared with the reported one where no significant

  19. Spectrophotometric, voltammetric and cytotoxicity studies of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives: A combined experimental-computational study

    Science.gov (United States)

    Akgemci, Emine Guler; Saf, Ahmet Ozgur; Tasdemir, Halil Ugur; Türkkan, Ercan; Bingol, Haluk; Turan, Suna Ozbas; Akkiprik, Mustafa

    2015-02-01

    In this study, 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) and its novel N(4) substituted derivatives were synthesized and characterized by different techniques. The optical band gap of the compounds and the energy of HOMO were experimentally examined by UV-vis spectra and cyclic voltammetry measurements, respectively. Furthermore, the conformational spaces of the compounds were scanned with molecular mechanics method. The geometry optimization, HOMO and LUMO energies, the energy gap of the HOMO-LUMO, dipole moment of the compounds were theoretically calculated by the density functional theory B3LYP/6-311++G(d,p) level. The minimal electronic excitation energy and maximum wavelength calculations of the compounds were also performed by TD-DFT//B3LYP/6-311++G(d,p) level of theory. Theoretically calculated values were compared with the related experimental values. The combined results exhibit that all compounds have good electron-donor properties which affect anti-proliferative activity. The cytotoxic effects of the compounds were also evaluated against HeLa (cervical carcinoma), MCF-7 (breast carcinoma) and PC-3 (prostatic carcinoma) cell lines using the standard MTT assay. All tested compounds showed antiproliferative effect having IC50 values in different range. In comparison with that of HMAT, it was obtained that while ethyl group on 4(N)-substituted position decreased in potent anti-proliferative effect, the phenyl group on the position increased in anti-proliferative effect for the tested cancer cell line. Considering the molecular energy parameters, the cytotoxicity activities of the compounds were discussed.

  20. 2-Hydroxy-4-n-butoxy-5-bromoacetophenone thiosemicarbazone as an extractive spectrophotometric reagent for nickel

    OpenAIRE

    K N Patel; K. S. Parikh; Rashmin Manubhai Patel

    2011-01-01

    2-hydroxy-4-n-butoxy-5-bromoacetophenone thiosemicarbazone (HBBrAT) is spectrophotometric reagent for nickel (II) in chloroform. The metal ion reacts with 2-hydroxy-4-n-butoxy-5-bromoacetophenone thiosemicarbazone (HBBrAT) forming a dark brown coloured complex in the pH range 7.0-11.0. The complex shows maximum absorption at 440 nm. Beer’s law is obeyed in the range 2.74-6.86 µg/mL. The molar absorptivity and Sandell’s sensitivity are found to be 5229 Lmol-1cm-1 and 0.0105 &...

  1. HUBUNGAN ANTARA KNOWLEDGE SHARING CAPABILITY, ABSORPTIVE CAPACITY DAN MEKANISME FORMAL: STUDI KASUS INDUSTRI TEKNOLOGI INFORMASI DAN KOMUNIKASI DI INDONESIA

    Directory of Open Access Journals (Sweden)

    Luciana Andrawina

    2008-01-01

    Full Text Available Knowledge is currently viewed as an important strategic resource in companies in order to gain competitive advantage. However, the success in generating competitive advantage will depend on the company’s ability to acquire and assimilate knowledge (potential absorptive capacity and to transform and exploit knowledge (realized absorptive capacity. This research proposed three hypotheses by processing the sampled data of 114 companies of information and communication technology industry in Indonesia. Based on the results, this study finds that knowledge sharing capability significantly influences potential absorptive capacity and the company’s ability to acquire and assimilate knowledge has a positive influence towards the company’s ability to transform and to exploit knowledge. The relationship between potential absorptive capacity and realized absorptive capacity is moderated by formal mechanism. Abstract in Bahasa Indonesia: Pengetahuan saat ini dipandang sebagai sumber daya strategis yang penting bagi perusahaan untuk dapat memiliki keunggulan bersaing. Kesuksesan perusahaan menghasilkan keunggulan bersaing tergantung pada kemampuan perusahaan mengakuisisi dan mengasimilasi pengetahuan (potential absorptive capacity dan mentransformasi dan mengeksploitasi pengetahuan (realized absorptive capacity. Penelitian ini mengajukan tiga hipotesis dengan mengolah data sampel dari 114 perusahaan pada industri teknologi informasi dan komunikasi di Indonesia. Hasil penelitian menemukan bahwa knowledge sharing capability berpengaruh signifikan terhadap potential absorptive capacity, kemampuan perusahaan mengakuisisi dan mengasimilasi berpengaruh signifikan terhadap kemampuan mentransformasi dan mengeksplotasi pengetahuan. Hubungan antara potential absorptive capacity dan realized absorptive capacity dimoderasi oleh mekanisme formal. Kata kunci: knowledge sharing capability, potential absorptive capacity, realized absorptive capacity, mekanisme formal

  2. Study on Absorption and Regeneration Performance of Novel Hybrid Solutions for CO2 Capture

    Institute of Scientific and Technical Information of China (English)

    Gao Jie; Yin Jun; Zhu Feifei; Chen Xin; Tong Ming; Kang Wanzhong; Zhou Yanbo; Lu Jun

    2016-01-01

    Recently, a kind of hybrid solution MEA-methanol shows a better CO2 capture performance over aqueous MEA solution. However, the vaporization of methanol is the biggest disadvantage that hinders its application, so it is necessary to minimize the vaporization of methanol during both the absorption and regeneration processes. In this work, two kinds of hybrid solutions were studied and compared with aqueous MEA solution and MEA-methanol solution, including MEA/TEA/methanol solution and MEA/glycerol/methanol solution. The absorption property of MEA/glycerol/methanol solution is better than aqueous MEA solution within a certain period of time and the absorption property of MEA/TEA/methanol solution is too poor to be used in CO2 capture. By increasing the concentration of TEA and decreasing the concentration of MEA, the absorption rate, CO2 capture efifciency and absorption capacity all decreased. Upon adding glycerol, the cyclic capacity decreased and the generation temperature increased, and moreover, the density and viscosity also increased considerably. So after adding TEA and glycerol, the CO2 capture performance of MEA-methanol solvent cannot be improved.

  3. A laboratory experimental setup for photo-absorption studies using synchrotron radiation

    CERN Document Server

    Shastri, A; Saraswati, P; Sunanda, K

    2002-01-01

    The photophysics beamline, which is being installed at the 450 MeV Synchrotron Radiation Source (SRS), Indus-l, is a medium resolution beamline useful for a variety of experiments in the VUV region viz. 500-2000 A. One of the major applications of this beamline is gas-phase photo-absorption studies. An experimental set up to be used for these experiments was designed, developed and tested in our laboratory. The setup consists of a high vacuum absorption cell, 1/4 m monochromator and detection system. For the purpose of testing, xenon and tungsten continuum sources were used and absorption spectra were recorded in the UV region. This setup was used to record the absorption spectrum of a few molecules like acetone, ammonia, benzene, formaldehyde and acetaldehyde in order to evaluate the performance of the experimental system which will subsequently be used with the photophysics beamline. Details of the design, fabrication and testing of the absorption cell and experimental procedures are presented in this repor...

  4. Thermoluminescence and optical absorption comparative studies with TLD-100 and pure LiF

    International Nuclear Information System (INIS)

    Optical absorption (OA) studies were carried out with LiF: Mg, Ti (TLD-100) and pure LiF exposed to X radiation, 77.4 C.kg-1 (3 x 105 R) with the aim of relating the thermoluminescent (TL) peaks presented by TLD-100 to its intrinsic and irradiation defects. After a 2800C thermal treatment for 15 minutes, an absorption band at 225 nm is observed in the TLD-100 OA spectrum. This band is not observed in the case of pure LiF. A correlation between TL peak 5 and the absorption band at 310 nm is established for TLD-100. These results agree with other publications and are explained. (author)

  5. Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

    Science.gov (United States)

    Linford, G J

    1973-06-01

    A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air. PMID:20125492

  6. Experimental Study on the Shock Absorption Performance of Combined Aluminium Honeycombs under Impact Loading

    Directory of Open Access Journals (Sweden)

    Lei Cao

    2015-01-01

    Full Text Available Shock absorption characteristics of combined aluminium honeycomb structures were studied experimentally. In the experiments, a testing platform was design to compare the shock absorption level of different honeycomb specimens quantitatively. The shock response curves of six test points mounted on the platform were recorded with acceleration sensors when the buffer was impacted by a bullet driven by high pressure gas. The maximum acceleration values in time domain and in specifically spectral domain were obtained based on spectral analysis. Comparing the data of combined aluminium honeycomb buffer and single aluminium honeycomb buffer, conclusion can be obtained that shock absorbing characteristic of combined aluminium honeycomb buffer is better. Furthermore, compression properties of three kinds of buffers were tested under quasi-static state. The energy absorption parameters were calculated. The results show suitable combined aluminium honeycomb buffer can smooth the stress and lower the energy applied to the testing platform.

  7. Parameter Optimization on Experimental Study to Reduce Ammonia Escape in CO2 Absorption by Ammonia Scrubbing

    Institute of Scientific and Technical Information of China (English)

    Hao Leng; Jianmin Gao; Mingyue He; Min Xie; Qian Du; Rui Sun; Shaohua Wu

    2016-01-01

    In order to research ammonia escape in CO2 absorption by ammonia scrubbing, ammonia escape was studied in CO2 absorption process using the bubbling reactor in different conditions as gas flow rate, CO2 ratio, absorbent temperature and ammonia concentration and quantity of escaped ammonia was measured by chemical titration. The results indicated that, the amount of ammonia escape can be around 20% of original amount in 90 min and the escaped amount will increase with the rise of gas flow rate, absorbent temperature, concentration of ammonia while decrease as CO2 ratio goes up. Through the analysis of the law of ammonia escape, at the same time, combined with ammonia escape and the influence of the relationship between the CO2 absorption efficiency, reducing ammonia escape working condition parameter optimization is given.

  8. A polarizable embedding DFT study of one-photon absorption in fluorescent proteins

    DEFF Research Database (Denmark)

    Beerepoot, Maarten; Steindal, Arnfinn H.; Kongsted, Jacob;

    2013-01-01

    A theoretical study of the one-photon absorption of five fluorescent proteins (FPs) is presented. The absorption properties are calculated using a polarizable embedding approach combined with density functional theory (PE-DFT) on the wild-type green fluorescent protein (wtGFP) and several of its...... optimization of the chromophores within a frozen protein environment is needed in order to reproduce the experimental trends. Explicit account of polarization in the force field is not needed to yield the correct trend between the different FPs, but is necessary for reproducing the experimentally observed red...

  9. Optical absorption and luminescence study of cobalt-doped magnesium aluminosilicate glass ceramics

    Science.gov (United States)

    Malyarevich, A. M.; Denisov, I. A.; Yumashev, K. V.; Dymshits, O. S.; Zhilin, A. A.

    2002-08-01

    Linear and nonlinear optical properties of cobalt-doped magnesium aluminosilicate transparent glass ceramics that were prepared under different conditions have been studied. It has been shown that absorption and luminescence spectra and absorption bleaching of these glass ceramics are defined mainly by tetrahedrally coordinated Co 2+ ions located in magnesium aluminum spinel nanocrystals. The lifetimes of the 4 T 1 ( 4 F) and 4 T 2 ( 4 F) excited states of the tetrahedral Co 2+ ions were found to be in the ranges 2540 and 120450 ns, respectively, depending on the Co concentration. 2002 Optical Society of America

  10. $\\beta$-decay studies using total absorption techniques some recent results

    CERN Document Server

    Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Karny, M; Kirchner, R; Maréchal, F; Miehé, C; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Scornet, G L; Taín, J L; Tengblad, O; Wittmann, V

    2004-01-01

    $\\beta$-decay experiments, are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called $\\textit{Pandemonium effect}$ is a critical problem in $\\beta$-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (25 refs).

  11. Studies on anodic oxide coating with low absorptance and high emittance on aluminum alloy 2024

    Energy Technology Data Exchange (ETDEWEB)

    Siva Kumar, C. [Department of Post-graduate studies in Chemistry, Central College, Bangalore (India); Sharma, A.K. [Thermal Process Section, ISRO Satellite Centre, Vimanapura Post, Bangalore (India); Mahendra, K.N.; Mayanna, S.M. [Department of Post-graduate studies in Chemistry, Central College, Bangalore (India)

    2000-01-01

    Anodization of AA 2024 in sulfuric acid bath containing glycerol, lactic acid and ammonium metavenadate has been studied to develop white anodic oxide coating. Investigation on the influence of various operating parameters - coating thickness, current density and ammonium metavenadate concentration on the optical properties was carried out to optimize the process. Infrared, atomic absorption spectroscopic techniques and scanning electron micrograph were used to characterize the coating. The obtained oxide coating provides a ratio of solar absorptance ({alpha}) to infrared emittance ({epsilon}), as low as 0.2. The optical properties and hardness values measured under optimum experimental conditions support its use as a thermal control coating.

  12. Laser-induced absorption and fluorescence studies of photochromic Schiff bases

    DEFF Research Database (Denmark)

    Kownacki, K.; Mordzinski, A.; Wilbrandt, R.;

    1994-01-01

    Three photochromic Schiff bases: N-salicylideneaniline (SA), N-salicylidene-1-naphthylamine (SN), and N,N-bis-(salicylidene)-p-phenylenediamine (Bsp), were studied in acetonitrile by means of steady-state and time-resolved absorption and fluorescence spectroscopy, as well as semiempirical quantum...... chemical calculations. In all these molecules, the transient absorption and two-step laser-induced fluorescence spectra of long-lived transients are remarkably similar. The photochromic species is tentatively assigned to the non-hydrogen bonded form of the proton transfer reaction product...

  13. Development of a dipodal Schiff base ligand with N-imine and O-naphtholate donors: A potential chelator towards Cu(II) metal ion established through potentiometric and spectrophotometric studies

    International Nuclear Information System (INIS)

    A novel hydroxynaphthaldehyde derived Schiff base ligand N,N’-bis-[2-[(2-hydroxy-1-naphthyl)methyleneamino]ethyl]propanediamide (DOTA2HNAP) containing nitrogen and oxygen donor atoms has been developed. The lowest energy molecular structure of DOTA2HNAP and its complexes with Cu (II) metal ion were examined by molecular mechanics using MM+ force which later was re-optimized by semi-empirical method. The theoretical IR and UV spectra of the ligand were obtained using semi empirical/ZINDO/PM3 and were compared with the experimental ones. The coordinating ability of DOTA2HNAP with H+ and Cu(II) ions was investigated in 1:99 (DMSO: water) binary solvent mixture at 25±1°C by potentiometric and spectrophotometric method. The electronic spectra of the ligand show three distinct peaks (253nm, 320nm and 360nm) implicating existence of the Schiff base in quinone form that was well supported by theoretical spectral studies. Out of various complex species forming in solution, all the metal ions show higher stability of complexes when in 1:1 metal-ligand stoichiometry, binding through two N-imine and two O-naphtholate groups

  14. Development of a dipodal Schiff base ligand with N-imine and O-naphtholate donors: A potential chelator towards Cu(II) metal ion established through potentiometric and spectrophotometric studies

    Energy Technology Data Exchange (ETDEWEB)

    Baral, Minati, E-mail: minatib@gmail.com; Gupta, Amit [Department of Chemistry, National Institute of Technology, Kurukshetra, Haryana (India); Kanungo, B. K. [Department of Chemistry, Sant Longowal Institute of Engineering and Technology, Longowal, Punjab (India)

    2015-08-28

    A novel hydroxynaphthaldehyde derived Schiff base ligand N,N’-bis-[2-[(2-hydroxy-1-naphthyl)methyleneamino]ethyl]propanediamide (DOTA2HNAP) containing nitrogen and oxygen donor atoms has been developed. The lowest energy molecular structure of DOTA2HNAP and its complexes with Cu (II) metal ion were examined by molecular mechanics using MM+ force which later was re-optimized by semi-empirical method. The theoretical IR and UV spectra of the ligand were obtained using semi empirical/ZINDO/PM3 and were compared with the experimental ones. The coordinating ability of DOTA2HNAP with H{sup +} and Cu(II) ions was investigated in 1:99 (DMSO: water) binary solvent mixture at 25±1°C by potentiometric and spectrophotometric method. The electronic spectra of the ligand show three distinct peaks (253nm, 320nm and 360nm) implicating existence of the Schiff base in quinone form that was well supported by theoretical spectral studies. Out of various complex species forming in solution, all the metal ions show higher stability of complexes when in 1:1 metal-ligand stoichiometry, binding through two N-imine and two O-naphtholate groups.

  15. Spectrophotometric determination of uranium using quercetin

    International Nuclear Information System (INIS)

    A spectrophotometric method for quantitative determination of uranium, using a flavone (quercetin) as complexing agent, is described. The method is based on the reaction between uranyl ion and alcoholic solution of quercetin with a complex formation of intense yellow color. (M.C.L.)

  16. Studies on mass energy-absorption coefficients and effective atomic energy-absorption cross sections for carbohydrates

    International Nuclear Information System (INIS)

    We measured here the mass attenuation coefficients (μ/ρ) of carbohydrates, Esculine (C15H16O9), Sucrose (C12H22O11), Sorbitol (C6H14O6), D-Galactose (C6H12O6), Inositol (C6H12O6), D-Xylose (C5H10O5) covering the energy range from 122 keV up to 1330 keV photon energies by using gamma ray transmission method in a narrow beam good geometry set-up. The gamma-rays were detected using NaI(Tl) scintillation detection system with a resolution of 8.2% at 662 keV. The attenuation coefficient data were then used to obtain the total attenuation cross-section (σtot), molar extinction coefficients (ε), mass-energy absorption coefficients (μen/ρ) and effective (average) atomic energy-absorption cross section (σa,en) of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data. - Highlights: • Compute the values of mass attenuation coefficients (μ/ρ) of some carbohydrates. • The values of (μen/ρ) i.e. mass energy-absorption coefficient are calculated. • Effective atomic energy-absorption cross sections (σa,en). • Comparison of all (μ/ρ), (μen/ρ), (σa,en) values with XCOM program. • The measured data for carbohydrates are useful in radiation dosimetry and other fields

  17. High Pressure X-ray Absorption Studies on Correlated-Electron Systems

    Energy Technology Data Exchange (ETDEWEB)

    Cornelius, Andrew L. [Univ. of Nevada, Las Vegas, NV (United States)

    2016-08-26

    This project used high pressure to alter the electron-electron and electron-lattice interactions in rare earth and actinide compounds. Knowledge of these properties is the starting points for a first-principles understanding of electronic and electronically related macroscopic properties. The research focused on a systematic study of x-ray absorption measurements on rare earth and actinide compounds.

  18. Neuron Mid-Infrared Absorption Study for Direct Optical Excitation of Neurons

    OpenAIRE

    Guo, Dingkai; Chen, Xing; Vadala, Shilpa; Leach, Jennie; Choa, Fow-Sen

    2011-01-01

    Neuron optical excitations are important for brain-circuitry explorations and sensory-neuron-stimulation applications. To optimize the stimulation, we identify neuron mid-IR absorption peaks in this study and discuss their meanings and delivery methods of mid-IR photons.

  19. Feasibility of a 3D human airway epithelial model to study respiratory absorption

    NARCIS (Netherlands)

    Reus, A.A.; Maas, W.J.M.; Jansen, H.T.; Constant, S.; Staal, Y.C.M.; Triel, J.J. van; Kuper, C.F.

    2014-01-01

    The respiratory route is an important portal for human exposure to a large variety of substances. Consequently, there is an urgent need for realistic in vitro strategies for evaluation of the absorption of airborne substances with regard to safety and efficacy assessment. The present study investiga

  20. An improved model for studies on transdermal drug absorption invivo in rats

    NARCIS (Netherlands)

    VOLLMER, U; MULLER, BW; WILFFERT, B; Peters, Thies

    1993-01-01

    In rats, transdermal drug absorption can be studied under physiological conditions by cannulating the peripheral skin vein, draining the area of the skin which is used for drug application, and collecting the blood. This method leads to decreased blood volume, which causes a reduction in skin blood

  1. An improved model for studies on transdermal drug absorption in-vivo in rats

    NARCIS (Netherlands)

    Vollmer, U.; Muller, B.W.; Wilffert, B.; Peters, Thies

    1993-01-01

    In rats, transdermal drug absorption can be studied under physiological conditions cannulating the peripheral skin vein, draining the area of the skin which is used for drug application, and collecting the blood. This method leads to decreased blood volume, which causes a reduction in skin blood flo

  2. Study of cancer cell lines with Fourier transform infrared (FTIR)/vibrational absorption (VA) spectroscopy

    DEFF Research Database (Denmark)

    Uceda Otero, E. P.; Eliel, G. S. N.; Fonseca, E. J. S.;

    2013-01-01

    In this work we have used Fourier transform infrared (FTIR) / vibrational absorption (VA) spectroscopy to study two cancer cell lines: the Henrietta Lacks (HeLa) human cervix carcinoma and 5637 human bladder carcinoma cell lines. Our goal is to experimentally investigate biochemical changes and d...

  3. Study on the rapid spectrophotometric determination of saccharin in liquid food%分光光度法快速测定液态食品中糖精含量的研究

    Institute of Scientific and Technical Information of China (English)

    蒋晗; 黄光荣

    2013-01-01

    A rapid spectrophotometric method was proposed to determine saccharin in liquid food.The saccharin reacted with azure Ⅰ to form a blue complex to be extracted with dichloromethane.The optimum absorption wavelength of this blue complex was 640 nm.The reaction was performed in 10.0 mL 0.2 mol/L pH 5.0 phosphatecitric acid buffer with 10.0 mL sample,0.5 mL 0.05% azure Ⅰ for 5 minutes,and then extracted with 10.0 mL dichloromethane.There existed a linear relationship between the absorbance and saccharin in the range of 0 to 120 mg/L.The detection limit of saccharin was 1.5 mg/L.The recovery rate was in the range of 90% to 103% with RSD less than 5.0% when the method was applied to determine saccharin in four kinds of liquid food.%利用糖精在磷酸缓冲液中与天青Ⅰ反应生成蓝色化合物,二氯甲烷能萃取糖精与天青Ⅰ形成的蓝色复合物而不萃取天青Ⅰ,通过分光光度法可以快速简便地测定液态食品中糖精的含量,糖精与天青Ⅰ形成的蓝色复合物的最大吸收波长为640 nm,当样品液取样量为10.0 mL、0.2 mol/L pH5.0磷酸氢二钠-柠檬酸缓冲液用量为10 mL、0.05%天青I溶液用量为0.5mL、显色时间为5 min、二氯甲烷萃取剂用量为10.0 mL时,糖精质量浓度在0~120 mg/L范围内与吸光度值呈线性,最低检出限为1.5 mg/L.该法应用于四种液态食品中糖精含量的测定,回收率在90%~103%之间,相对标准偏差小于5.0%.

  4. The potential of UV-VIS-NIR absorption spectroscopy in glass studies

    Science.gov (United States)

    Meulebroeck, Wendy; Baert, Kitty; Ceglia, Andrea; Cosyns, Peter; Wouters, Hilde; Nys, Karin; Terryn, Herman; Thienpont, Hugo

    Absorption spectroscopy is the technique that measures the absorption of radiation as a function of wavelength, due to its interaction with the material. During a research project funded by our home university, we were able to investigate the possibilities of this technique to study ancient glasses. One of our main conclusions is that UV-VIS-NIR absorption spectroscopy is especially suited to characterize colored artifacts in terms of composition and furnace conditions. Moreover, for naturally colored window glasses, we have shown that this technique allows us to classify fragments based on differences in iron impurity levels. It is a semi-quantitative analysis tool that can be applied for a first-line analysis of (large) glass collections. Thanks to the commercial available portable instruments, these measurements can be performed at relative high speed and this in-situ if necessary. To illustrate the possibilities of this technique, we describe in this paper two case-studies. In a first test-case we analyze 63 naturally colored window glasses and demonstrate how groups with different iron concentrations can be identified by calculating the absorption edge position from the measured optical spectrum. In a second case-study 8 modern naturally colored and 31 intentionally colored Roman glass fragments are the point of focus. For these samples we first estimate which samples are potentially fabricated under the same furnace conditions. This is done based on the calculated color values. Finally we identify the type of applied colorants.

  5. Novel spectrophotometric method for detection and estimation of butanol in acetone-butanol-ethanol fermenter.

    Science.gov (United States)

    Maiti, Sampa; Sarma, Saurabh Jyoti; Brar, Satinder Kaur; Bihan, Yann Le; Drogui, Patrick; Buelna, Gerardo; Verma, Mausam; Soccol, Carlos Ricardo

    2015-08-15

    A new, simple, rapid and selective spectrophotometric method has been developed for detection and estimation of butanol in fermentation broth. The red colored compound, produced during reduction of diquat-dibromide-monohydrate with 2-mercaptoethanol in aqueous solution at high pH (>13), becomes purple on phase transfer to butanol and gives distinct absorption at λ520nm. Estimation of butanol in the fermentation broth has been performed by salting out extraction (SOE) using saturated K3PO4 solution at high pH (>13) followed by absorbance measurement using diquat reagent. Compatibility and optimization of diquat reagent concentration for detection and estimation of butanol concentration in the fermentation broth range was verified by central composite design. A standard curve was constructed to estimate butanol in acetone-ethanol-butanol (ABE) mixture under optimized conditions. The spectrophotometric results for butanol estimation, was found to have 87.5% concordance with the data from gas chromatographic analysis. PMID:25966390

  6. A study to maximize the crash energy absorption efficiency within the limits of crash space

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bae Young; Jeong, Choong Min; Suh, Myung Won [Sungkyunkwan University, Suwon (Korea, Republic of); Kim, Si Woo [Korea Automobile Testing and Research Institute, Hwaseong (Korea, Republic of)

    2012-04-15

    The design of an engine room is important to protect the passenger from a crash impact by improving the absorption of the crash impact energy. The side member in the engine room absorbs most of the crash impact energy when the vehicle experiences a frontal crash. The side member is of two types: hat and 'U.' Analysis of the extent of energy absorption and the mechanism of the side member are necessary through a collapse mode in various load conditions. In this study, the design of experiments was used for evaluating the characteristics of the absorption of crash energy by side members through design variables. First, crash analysis was performed by experiment number extracted from the design of the experiment. Then, using the results of crash analysis, multiple regressions were conducted and sensitivity analysis performed for each design variable. Finally, the optimum design was developed for maximizing the absorption energy per unit weight considering various boundary conditions. In the present study, as a basic step for modeling the fatigue behavior of an extruded Al alloy cylinder, the fatigue crack growth data of the alloy was collected in two orientations. Microstructural analysis revealed that the material had recrystallized grains and clusters of constituent particles aligned in the direction of extrusion. Fatigue life of the samples revealed a shorter fatigue life representing a higher fatigue crack growth rate in the transverse direction.

  7. Analysis of Protein by Spectrophotometric and Computer Colour Based Intensity Method from Stem of Pea (Pisum sativum at Different Stages

    Directory of Open Access Journals (Sweden)

    Afsheen Mushtaque Shah

    2010-12-01

    Full Text Available In this study proteins were analyzed from pea plants at three different growth stages of stem by spectrophotometric i.e Lowry and Bradford quantitative methods and computer colour intensity based method. Though Spectrophotometric methods are regarded as classical methods, we report an alternate computer based method which gave comparable results. Computer software was developed the for protein analysis which is easier, time and money saving method as compared to the classical methods.

  8. Kinetic study of carbon dioxide absorption into glycine promoted diethanolamine (DEA)

    Science.gov (United States)

    Pudjiastuti, Lily; Susianto, Altway, Ali; IC, Maria Hestia; Arsi, Kartika

    2015-12-01

    In industry, especially petrochemical, oil and natural gas industry, required separation process of CO2 gas which is a corrosive gas (acid gas). This characteristic can damage the plant utility and piping systems as well as reducing the caloric value of natural gas. Corrosive characteristic of CO2 will appear in areas where there is a decrease in temperature and pressure, such as at the elbow pipe, tubing, cooler and injector turbine. From disadvantages as described above, then it is important to do separation process in the CO2 gas stream, one of the method for remove CO2 from the gas stream is reactive absorption using alkanolamine based solution with promotor. Therefore, this study is done to determine the kinetics constant of CO2 absorption in diethanolamine (DEA) solution using a glycine promoter. Glycine is chosen as a promoter because glycine is a primary amine compound which is reactive, moreover, glycine has resistance to high temperatures so it will not easy to degradable and suitable for application in industry. The method used in this study is absorption using laboratory scale wetted wall column equipment at atmospheric of pressure. This study will to provide the reaction kinetics data information in order to optimize the separation process of CO2 in the industrialized world. The experimental results show that rising temperatures from 303,15 - 328,15 K and the increase of concentration of glycine from 1% - 3% weight will increase the absorption rate of carbon dioxide in DEA promoted with glycine by 24,2% and 59,764% respectively, also the reaction kinetic constant is 1.419 × 1012 exp (-3634/T) (m3/kmol.s). This result show that the addition of glycine as a promoter can increase absorption rate of carbon dioxide in diethanolamine solution and cover the weaknesses of diethanolamine solution.

  9. Spectrophotometric Determination of Aminoglycoside Antibiotics Based on their Oxidation by Potassium Permanganate

    Energy Technology Data Exchange (ETDEWEB)

    El-Didamony, A. M.; Ghoneim, A. K.; Telebany, A. M. [Zagazig University, Zagazig (Egypt); Amin, A. S. [Banha University, Banha (Egypt)

    2006-08-15

    A rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of neomycin and streptomycin either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C), and methylene blue (method D), in the same acid medium at a suitable λ{sub max}=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 5-10 and 2-7 mg mL{sup -1} for neomycin and streptomycin, respectively. The apparent molar absorptivity and sandell sensitivity values are in the range 5.47-6.20x10{sup 4}, 2.35-2.91x10{sup 5} L mol{sup -1} cm{sup -1} and 7.57-8.59, 5.01-6.2 ng cm{sup -2} for neomycin and streptomycin, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods.

  10. Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate.

    Science.gov (United States)

    Gouda, Ayman Abou El-Fetouh; El-Sheikh, Ragaa; El Shafey, Zeineb; Hossny, Nagda; El-Azzazy, Rham

    2008-12-01

    Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 2.0-16 and 2.0-15 μg mL(-1) for PiCl and DEX, respectively with correlation coefficient (n=6) ≥ 0.9993. The apparent molar absorptivity and sandell sensitivity values are in the range 1.062-1.484 × 10(4), 3.35-4.51 × 10(4) L mol(-1) cm(-1) and 29.36-41.03, 8.21-11.06 ng cm(-2) for PiCl and DEX, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods. PMID:23675101

  11. Development and Validation of a UV - Spectrophotometric Method for Quantification of Atorvastatin in Tablets

    Directory of Open Access Journals (Sweden)

    Mondal A

    2012-01-01

    Full Text Available A UV-spectrophotometric method has been developed for the quantitativeestimation of atorvastatin in tablet. The present study describes development and validation of UV-spectroscopic method for estimationof atorvastatin in tablet dosage form and validation of newlydeveloped method. During development of analytical method methanol:phosphate buffer (20:80,methanol:water(20:80,methanol:water (50:50,acetonitrile:water (10:90were tried but drug was found to be solublein methanol:water (50:50. Standard stock solution was prepared in methanol: water (50:50. The detection wave length (λmax was found tobe 248nm.Calibration curves were prepared.The proposed method obeysBeer's law in the range of 5-15μg/ml. Absorption maxima was determinedwith 10 μg/ml by scanning in the range of 200-400nm.Percent recoverystudies are in the range of 98.78%-100.36%. The method was validated in terms specificity,linearity,accuracy,range,precision,repeatability,robustness,system suitability,stability of analytical solution.Results of analysis were validated statistically and by specificity studies.From that it was observed that there is no interference of blank,excipients during the estimation of drug in formulation. This showsthe adaptability of the method for routine estimation of atorvastatinin tablet dosage form.

  12. Studies on mass energy-absorption coefficients and effective atomic energy-absorption cross sections for carbohydrates

    Science.gov (United States)

    Ladhaf, Bibifatima M.; Pawar, Pravina P.

    2015-04-01

    We measured here the mass attenuation coefficients (μ/ρ) of carbohydrates, Esculine (C15H16O9), Sucrose (C12H22O11), Sorbitol (C6H14O6), D-Galactose (C6H12O6), Inositol (C6H12O6), D-Xylose (C5H10O5) covering the energy range from 122 keV up to 1330 keV photon energies by using gamma ray transmission method in a narrow beam good geometry set-up. The gamma-rays were detected using NaI(Tl) scintillation detection system with a resolution of 8.2% at 662 keV. The attenuation coefficient data were then used to obtain the total attenuation cross-section (σtot), molar extinction coefficients (ε), mass-energy absorption coefficients (μen/ρ) and effective (average) atomic energy-absorption cross section (σa,en) of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

  13. Study on solid phase extraction and spectrophotometric determination of vanadium with 2,3-dichloro-6-(2,7-dihydroxy-1-naphthylazo)quinoxaline

    Science.gov (United States)

    Amin, Alaa S.; Saber, Amr L.; Mohammed, T. Y.

    2009-07-01

    A sensitive, selective and rapid method has been developed for the determination micrograms per liter level of vanadium ion based on the rapid reaction of vanadium(V) with 2,3-dichloro-6-(2,7-dihydroxy-1-naphthylazo)quinoxaline (DCDHNAQ) and the solid phase extraction of the colored complex with C18 cartridge. The DCDHNAQ reacts with V(V) in the presence of citric acid-sodium hydroxide buffer solution (pH 3.3) and benzyldimethyl tetradecylammonium chloride (zephiramine) medium to form a violet complex of a molar ratio 1:2 [V(V) to DCDHNAQ]. This complex was enriched by solid phase extraction with C18 cartridge and the enrichment factor of 100 was obtained by elution of the complex from the cartridge with acetonitrile. The molar absorptivity and Sandell sensitivity of the complex are 2.45 × 10 5 L mol -1 cm -1 and 0.0208 ng cm -2 at 573 nm in the measured solution. Beer's law is obeyed in the range of 0.01-0.45 μg mL -1, whereas Ringbom optimum concentration ranges found to be 0.025-0.425 μg mL -1. The detection and quantification limits are 3.2 and 9.9 μg L -1, respectively in the original samples. This method was applied to the determination of vanadium(V) in steel, soil, water and biological samples with good results.

  14. Study on the prediction of visible absorption maxima of azobenzene compounds

    Institute of Scientific and Technical Information of China (English)

    LIU Jun-na; CHEN Zhi-rong; YUAN Shen-feng

    2005-01-01

    The geometries of azobenzene compounds are optimized with B3LYP/6-311 G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWFπ-π=-8.1537+6.5638BLN-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules' orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).

  15. Study on Relative COP Changes with Increasing Heat Input Temperatures of Double Effect Steam Absorption Chillers

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2016-01-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers are mainly of double effect type. The COP of double effect varies from 0.7 to 1.2 depending on operation and maintenance practices of the chillers. Heat input to the chillers during operations could have impact on the COP of the chillers. This study is on relative COP changes with increasing the heat input temperatures for a steam absorption chiller at a gas fueled cogeneration plant. Reversible COP analysis and zero order model were used for evaluating COP of the chiller for 118 days operation period. Results indicate increasing COP trends for both the reversible COP and zero model COP. Although the zero model COP are within the range of double effect absorption chiller, it is not so for the actual COP. The actual COP is below the range of normal double effect COP. It is recommended that economic replacement analysis to be undertaken to assess the feasibility either to repair or replace the existing absorption chiller.

  16. In Situ and in Vivo Study of Nasal Absorption of Paeonol in Rats

    Directory of Open Access Journals (Sweden)

    Pengyue Li

    2010-11-01

    Full Text Available The objective of this work was to study the in situ and in vivo nasal absorption of paeonol. A novel single pass in situ nasal perfusion technique was applied to examine the rate and extent of nasal absorption of paeonol by rats. Various experimental conditions, such as perfusion rate, pH, osmotic pressure and drug concentration, were investigated. The in situ experiments showed that the nasal absorption of paeonol was not dependent on drug concentration, and fitted a first order process. The absorption rate constant, Ka, increased with an increase in perfusion speed. Paeonol was better absorbed in acidic solutions than in neutral or alkaline solutions. The value of Ka was higher in a hypertonic environment than under isotonic or hypotonic conditions. In vivo studies of paeonol absorption were carried out in rats and the pharmacokinetics parameters of intranasal (i.n. and intragastric (i.g. administration were compared with intravenous (i.v. administration. The bioavailabilities of paeonol were 52.37% and 15.81% for i.n. and i.g, respectively, while Tmax values were 3.05 ± 1.46 min and 6.30 ± 0.70 min. MRT (Mean Residence Time were 23.19 ± 6.46 min, 41.49 ± 2.96 min and 23.09 ± 5.88 min for i.n., i.g. and i.v. methods, respectively. The results demonstrate that paeonol could be absorbed promptly and thoroughly by i.n. administration in rats.

  17. Spectrophotometric determination of dopaminergic drugs used for Parkinson's disease, cabergoline and ropinirole, in pharmaceutical preparations.

    Science.gov (United States)

    Onal, Armağan; Cağlar, Sena

    2007-04-01

    Simple and reproducible spectrophotometric methods have been developed for determination of dopaminergic drugs used for Parkinson's disease, cabergoline (CAB) and ropinirole hydrochloride (ROP), in pharmaceutical preparations. The methods are based on the reactions between the studied drug substances and ion-pair agents [methyl orange (MO), bromocresol green (BCG) and bromophenol blue (BPB)] producing yellow colored ion-pair complexes in acidic buffers, after extracting in dichloromethane, which are spectrophotometrically determined at the appropriate wavelength of ion-pair complexes. Beer's law was obeyed within the concentration range from 1.0 to 35 microg ml(-1). The developed methods were applied successfully for the determination of these drugs in tablets.

  18. Application of potassium permanganate to spectrophotometric assay of metoclopramide hydrochloride in pharmaceuticals

    Science.gov (United States)

    Devi, O. Zenita; Basavaiah, K.; Vinay, K. B.

    2012-01-01

    Two simple, sensitive, and cost-effective spectrophotometric methods are described for the determination of metoclopramide hydrochloride (MCP) in pharmaceutical dosage forms. The methods are based on a redox reaction between MCP and KMnO4 in alkaline and acid media. Direct spectrophotometry (method A) involves treating MCP with permanganate in an NaOH medium and measuring a bluish green product at 610 nm. In indirect spectrophotometry (method B), MCP is treated with a fixed concentration of KMnO4 in an H2SO4 medium, and after a specified time, the unreacted KMnO4 is measured at 545 nm. Under optimum assay conditions, Beer's law is obeyed over the ranges of 0.75-12.0 and 2.5-30.0 g/ml for methods A and B, respectively. Molar absorptivity values are calculated to be 2.33•104 and 2.66•104 l/mol cm for methods A and B, respectively, and corresponding Sandell's sensitivity values are 0.015 and 0.013 g/cm2. Limits of detection (LOD) and quantification (LOQ) are also reported. The applicability of the developed methods was demonstrated by the determination of MCP in tablet and injection forms. The accuracy and reliability of the proposed methods were further ascertained by recovery studies via standard addition technique.

  19. Spectrophotometric Method for Quantitative Determination of Cefixime in Bulk and Pharmaceutical Preparation Using Ferroin Complex

    Science.gov (United States)

    Naeem Khan, M.; Qayum, A.; Ur Rehman, U.; Gulab, H.; Idrees, M.

    2015-09-01

    A method was developed for the quantitative determination of cefixime in bulk and pharmaceutical preparations using ferroin complex. The method is based on the oxidation of the cefixime with Fe(III) in acidic medium. The formed Fe(II) reacts with 1,10-phenanthroline, and the ferroin complex is measured spectrophotometrically at 510 nm against reagent blank. Beer's law was obeyed in the concentration range 0.2-10 μg/ml with a good correlation of 0.993. The molar absorptivity was calculated and was found to be 1.375×105 L/mol × cm. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.030 and 0.101 μg/ml respectively. The proposed method has reproducibility with a relative standard deviation of 5.28% (n = 6). The developed method was validated statistically by performing a recoveries study and successfully applied for the determination of cefixime in bulk powder and pharmaceutical formulations without interferences from common excipients. Percent recoveries were found to range from 98.00 to 102.05% for the pure form and 97.83 to 102.50% for pharmaceutical preparations.

  20. Pregabalin and Tranexamic Acid Evaluation by Two Simple and Sensitive Spectrophotometric Methods

    Directory of Open Access Journals (Sweden)

    Nawab Sher

    2015-01-01

    Full Text Available This paper demonstrates colorimetric visible spectrophotometric quantification methods for amino acid, namely, tranexamic acid and pregabalin. Both drugs contain the amino group, and when they are reacted with 2,4-dinitrophenol and 2,4,6-trinitrophenol, they give rise to yellow colored complexes showing absorption maximum at 418 nm and 425 nm, respectively, based on the Lewis acid base reaction. Detailed optimization process and stoichiometric studies were conducted along with investigation of thermodynamic features, that is, association constant and standard free energy changes. The method was linear over the concentration range of 0.02–200 µgmL−1 with correlation coefficient of more than 0.9990 in all of the cases. Limit of detection was in range from 0.0041 to 0.0094 µgmL−1 and limit of quantification was in the range from 0.0137 to 0.0302 µgmL−1. Excellent recovery in Placebo spiked samples indicated that there is no interference from common excipients. The analytical methods under proposal were successfully applied to determine tranexamic acid and pregabalin in commercial products. t-test and F ratio were evaluated without noticeable difference between the proposed and reference methods.

  1. SPECTROPHOTOMETRIC METHODS FOR SIMULTANEOUS ESTIMATION OF CEFUROXIME SODIUM AND SULBACTAM SODIUM IN INJECTON

    Directory of Open Access Journals (Sweden)

    F.M. Patel et al

    2012-09-01

    Full Text Available Cefuroxime is a 2nd-generation cephalosporin and Sulbactam is a β-Lactamase inhibitor. The combination formulation is used for the treatment of lower respiratory tract infection. Two new, simple, accurate and precise UV spectrophotometric methods have been developed and validated for the simultaneous determination of Cefuroxime Sodium (CEF and Sulbactam Sodium (SUL in their combined dosage forms. First method is based on simultaneous estimation of Cefuroxime at 279nm and Sulbactam at 259 nm, while other Q‐absorption Ratio method using two wavelengths, 259nm (λmax of SUL and 272nm (Isoabsorptive point. 0.01 N NaOH was the solvent used in all methods. Cefuroxime Sodium showed linearity in the range of 8-32μg/mL and Sulbactam sodium showed linearity in the range of 4-16μg/mL in all the methods. All methods were validated statistically and recovery studies were carried out. All methods were found to be accurate, precise and reproducible. These methods were applied to the assay of the drugs in marketed formulation, which were found in the range of 98.0% to 100.0% of the labelled value for both Cefuroxime and Sulbactam. Hence, the methods herein described can be successfully applied in quality control of combined pharmaceutical dosage forms.

  2. METHOD DEVELOPMENT AND VALIDATION OF DULOXETINE HYDROCHLORIDE IN BULK AND FORMULATION USING UV SPECTROPHOTOMETRIC METHOD

    Directory of Open Access Journals (Sweden)

    Kishore Methuku

    2012-06-01

    Full Text Available New, simple and cost effective UV-spectrophotometric method was developed for the estimation of Duloxetine hydrochloride in bulk formulations. Duloxetine hydrochloride was estimated at 290 nm in 20% Acetonitrie. Linearity range was found to be 10–50 μg ml–1 (regression equation: 0.017 + 0.016; r2 = 0.999. The apparent molar absorptivity was found to be 5.922×10-3 mol−1 cm−1 in 20% Acetonitrile. These methods were tested and validated for various parameters according to ICH guidelines and USP. The quantitation limits were found to be 0.2405 μg ml–1 and 0.7289 μg ml–1 in 20% Acetonitrile respectively. The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation < 2%, while being simple, cheap and less time consuming and can be suitably applied for the estimation of Duloxetine hydrochloride in different dosage forms and dissolution studies.

  3. Derivative and Q-analysis spectrophotometric methods for estimation of hydrochlorothiazide and olmesartan medoxomil in tablets

    Directory of Open Access Journals (Sweden)

    Bhusari K

    2009-01-01

    Full Text Available Two methods for simultaneous estimation of hydrochlorothiazide and olmesartan medoxomil in combined tablet dosage form have been developed. The first method is the application of Q-analysis method (absorbance ratio, which involves the formation of Q-absorbance equation at 264 nm (isobestic point and at 271 nm, the maximum absorption of hydrochlorothiazide. The linearity ranges for hydrochlorothiazide and olmesartan medoxomil were 2.5-22.5 μg/ml and 4-36 μg/ml, respectively. The second method is based on the derivative spectrophotometric method at zero crossing wavelengths. The linearity ranges for hydrochlorothiazide and olmesartan medoxomil were 2.5-20 μg/ml and 4-32 μg/ml, respectively. The accuracy of the methods were assessed by recovery studies and was found to be 100.45% ±0.4215 and 100.24% ±0.3783 for absorbance ratio method and 99.39% ±0.221 and 99.72% ±0.11 for first derivative method, for hydrochlorothiazide and olmesartan medoxomil, respectively. These methods are simple, accurate and rapid, those require no preliminary separation and can therefore be used for routine analysis of both drugs in quality control laboratories.

  4. Kinetic spectrophotometric method for determination of amlodipine besylate in its pharmaceutical tablets

    Institute of Scientific and Technical Information of China (English)

    Ashraf M. Mahmoud; Hanaa M. Abdel-Wadood; Niveen A. Mohamed

    2012-01-01

    A simple and sensitive kinetic spectrophotometric method has been developed and validated for determination of amlodipine besylate (AML). The method was based on the condensation reaction of AML with 7-chloro-4-nitro-2,1,3-benzoxadiazole in an alkaline buffer (pH 8.6) producing a highly colored product. The color development was monitored spectrophometrically at the maximum absorption λmax 470 nm. The factors affecting the reaction were studied and the conditions were optimized. The stoichiometry of the reaction was determined, and the reaction pathway was postulated. Moreover, both the activation energy and the specific rate constant (at 70 ℃) of the reaction were found to be 6.74 kcal mole-1 and 3.58 s -1, respectively. The initial rate and fixed time methods were utilized for constructing the calibration graphs lbr the determination of AML concentration. Under the optimum reaction conditions, the limits of detection and quantification were 0.35 and 1.05 ug/mL, respectively. The precision of the method was satisfactory; the relative standard deviations were 0.85-1.76%. The proposed method was successfully applied to the analysis of AML in its pure form and tablets with good accuracy; the recovery percentages ranged from 99.55 ± 1.69% to 100.65 ±1.48%. The results were compared with that of the reported method.

  5. Development and Validation of Spectrophotometric Methods for Estimating Sulfamethoxazole in Pharmaceutical Preparations

    Directory of Open Access Journals (Sweden)

    Sangita Sharma

    2010-07-01

    Full Text Available Four simple, sensitive, accurate, and rapid visible spectrophotometric methods (A, B, C and D have been developed for the estimation of sulfamethoxazole in pharmaceutical Preparation. They are based on the diazotization of sulfamethoxazole with sodium nitrite and hydrochloric acid followed by coupling with N-(1-naphthyl ethylenediamine dihydrochloride (Method A to form pink coloured chromogen, diphenylamine (Method B to form pink coloured chromogen, β-napthol (in alkaline medium (Method C to form a orange yellow coloured chromogen and Resorcinol (in alkaline medium (Method D to form orange red coloured chromogen and exhibiting absorption maxima λmax at 536 nm, 516 nm, 477 nm and 502 nm respectively. The coloured chromogens formed are stable for more than 2 h. Beer's law was obeyed in the concentration range of 4 -12 µg mL-1 in method A , 2 – 10 µg mL-1 in method B, 5 – 25 µg mL-1 in method C and 1 – 5 µg mL-1 in method D respectively. The Results of the four analysis have been validated statistically and by recovery studies. The results obtained in the proposed methods are in good agreements with labeled amounts, when marketed pharmaceutical preparations are analyzed.

  6. Study on the interaction between diphenhydramine and erythrosin by absorption, fluorescence and resonance Rayleigh scattering spectra

    Institute of Scientific and Technical Information of China (English)

    TANG XiaoLing; LIU ZhongFang; LIU ShaoPu; HU XiaoLi

    2007-01-01

    In pH 4.5 Britton-Robinson (BR) buffer solution, erythrosin (ET) can react with diphenhydramine (DP) to form a 1:1 ion-association complex, which not only results in the change of the absorption spectra, but also results in the great enhancement of resonance Rayleigh scattering (RRS) and the quenching of fluorescence. Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 580 nm.In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reaction and the properties of an analytical chemistry were investigated. A sensitive, simple and new method for the determination of DP by using erythrosin as a probe has been developed. The detection limits for DP were 0.0020 μg/mL for RRS method, 0.088 μg/mL for absorption method and 0.094 μg/mL for fluorophotometry. There was a linear relationship between the absorbance, RRS and fluorescence intensities and the drug concentration in the range of 0.0067-2.0, 0.29-6.4 and 0.31-3.2 μg/mL, respectively. The effects of the interaction of diphenhydramine and erythrosin on the absorption, fluorescence and resonance Rayleigh scattering spectra were discussed. In light polarization experiment, the polarization of RRS at maximum wavelength was measured to be P = 0.9779, and it revealed that the RRS spectrum of DP-ET complex consists mostly of resonance scattering and few resonance fluorescence. In this study, enthalpy of formation and mean polarizability were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra and the energy transfer between absorption, fluorescence and RRS were discussed.

  7. Kinetic Spectrophotometric Determination of Certain Cephalosporins in Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    Mahmoud A. Omar

    2009-01-01

    Full Text Available A simple, reliable, and sensitive kinetic spectrophotometric method was developed for determination of eight cephalosporin antibiotics, namely, Cefotaxime sodium, Cephapirin sodium, Cephradine dihydrate, Cephalexin monohydrate, Ceftazidime pentahydrate, Cefazoline sodium, Ceftriaxone sodium, and Cefuroxime sodium. The method depends on oxidation of each of studied drugs with alkaline potassium permanganate. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 610 nm. The initial rate and fixed time (at 3 minutes methods are utilized for construction of calibration graphs to determine the concentration of the studied drugs. The calibration graphs are linear in the concentration ranges 5–15 g mL−1 and 5–25 g mL−1 using the initial rate and fixed time methods, respectively. The results are validated statistically and checked through recovery studies. The method has been successfully applied for the determination of the studied cephalosporins in commercial dosage forms. Statistical comparisons of the results with the reference methods show the excellent agreement and indicate no significant difference in accuracy and precision.

  8. Kinetic spectrophotometric determination of certain cephalosporins in pharmaceutical formulations.

    Science.gov (United States)

    Omar, Mahmoud A; Abdelmageed, Osama H; Attia, Tamer Z

    2009-01-01

    A simple, reliable, and sensitive kinetic spectrophotometric method was developed for determination of eight cephalosporin antibiotics, namely, Cefotaxime sodium, Cephapirin sodium, Cephradine dihydrate, Cephalexin monohydrate, Ceftazidime pentahydrate, Cefazoline sodium, Ceftriaxone sodium, and Cefuroxime sodium. The method depends on oxidation of each of studied drugs with alkaline potassium permanganate. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 610 nm. The initial rate and fixed time (at 3 minutes) methods are utilized for construction of calibration graphs to determine the concentration of the studied drugs. The calibration graphs are linear in the concentration ranges 5-15 mug mL(-1) and 5-25 mug mL(-1) using the initial rate and fixed time methods, respectively. The results are validated statistically and checked through recovery studies. The method has been successfully applied for the determination of the studied cephalosporins in commercial dosage forms. Statistical comparisons of the results with the reference methods show the excellent agreement and indicate no significant difference in accuracy and precision. PMID:20140078

  9. Autoradiographic study on percutaneous absorption of several oils useful for cosmetics

    International Nuclear Information System (INIS)

    Percutaneous absorption of five 14C-labelled oils, n-octadecane, decanoxy decane, 2-hexyldecanoxy octane, isopropyl myristate and glyceryl tri-(oleate), commonly used is cosmetics were studied from the point of view of their safety. In whole body autoradiography of hairless mice, there was no visible penetration into the skin and organs, whereas microautoradiography of guinea pigs showed local penetration. Isopropyl myristate penetrated to the greatest extent, whereas 2-hexyldecanoxy octane was hardly absorbed. Percutaneous absorption of these two oils, therefore, was examined in Angora rabbits by microautoradiography simultaneously with skin irritation potential by a histological method, from the following aspects, (1) patterns of penetration and irritation in relation to application time and (2) fate within the skin and pattern of irritation after application. In addition, intradermal metabolic fate was studied in vivo. (author)

  10. Optical Absorption and Electron Injection of 4-(Cyanomethylbenzoic Acid Based Dyes: A DFT Study

    Directory of Open Access Journals (Sweden)

    Yuehua Zhang

    2015-01-01

    Full Text Available Density functional theory (DFT and time-dependent density functional theory (TDDFT calculations were carried out to study the ground state geometries, electronic structures, and absorption spectra of 4-(cyanomethylbenzoic acid based dyes (AG1 and AG2 used for dye-sensitized solar cells (DSSCs. The excited states properties and the thermodynamical parameters of electron injection were studied. The results showed that (a two dyes have uncoplanar structures along the donor unit and conjugated bridge space, (b two sensitizers exhibited intense absorption in the UV-Vis region, and (c the excited state oxidation potential was higher than the conduction band edge of TiO2 photoanode. As a result, a solar cell based on the 4-(cyanomethylbenzoic acid based dyes exhibited well photovoltaic performance. Furthermore, nine dyes were designed on the basis of AG1 and AG2 to improve optical response and electron injection.

  11. Derivative Spectrophotometric Estimation of Ondansetron and Paracetamol

    OpenAIRE

    Ravi Kumar, P.; M Murali Krishna; P. Bhanu Prakash; B. Anil Kumar; P. Madhusudhan

    2006-01-01

    A simple and reproducible spectrophotometric method, requiring no prior separation, has been developed for the estimation of ondansetron and paracetamol in combined dosage form. First order derivative spectroscopy method is adopted to eliminate spectral interference. The methods obey Beer’s Law in concentration ranges employed for evaluation. Ondansetron and paracetamol have λmax at 302 nm and 246 nm respectively in methanol. The results of analysis have been validated statistically and recov...

  12. Spectrophotometric determination of fluorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.; Smith, V.C.

    1964-01-01

    The rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate, the sinter-cake leached with water and the resulting solution filtered. Fluorine is separated from the acidified filtrate by steam distillation and determined spectrophotometrically by means of a zirconium-SPADNS reagent. If a multiple-unit distillation apparatus is used, 12 determinations can be completed per man-day. ?? 1964.

  13. Spectrophotometric Estimation of Azithromycin in Tablets

    OpenAIRE

    B. K. Jayanna; G. Nagendrappa; Arunkumar,; Gowda, N.

    2012-01-01

    The present manuscript describes a simple, sensitive, accurate, precise and economical visible spectrophotometric method for the estimation of azithromycin from tablet formulation. The method is based on the reduction of potassium permanganate in alkaline medium with azithromycin. The measurement of decrease in absorbance of potassium permanganate at 547 nm was done, as it decolourises upon reduction by azithromycin. The method was used to determine between 2 and 20 μg/ml of azithromycin in t...

  14. An Atlas of Spectrophotometric Landolt Standard Stars

    OpenAIRE

    Stritzinger, Maximilian; Suntzeff, Nicholas B.; Hamuy, Mario; Challis, Peter; Demarco, Ricardo; Germany, Lisa; Soderberg, A. M.

    2005-01-01

    We present CCD observations of 102 Landolt standard stars obtained with the R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models we have extended the flux points to our six spectrophotometric secondary standards, in both the blue and the red, allowing us to produce flux-calibrated spectra that span a wavelength range from 3050 \\AA to 1.1 \\micron. Mean differences between UBVRI spectrophotometry computed using Bessell's standard passbands and Landolt's published photom...

  15. Spectrophotometric determination of cefaclor in pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    Ivama Viviane M.

    1999-01-01

    Full Text Available A simple spectrophotometric method is proposed for the determination of cefaclor. The method involves alkaline hydrolysis of the drug in ammonia buffer solution at pH 10 to yield diketopiperazine-2,5-dione derivative and subsequent measurement at 340 nm. Beer's law is obeyed in the concentration range 1.8 - 55 mg/mL. The proposed method was successfully applied to the determination of cefaclor in pharmaceutical formulations.

  16. An Empirical Study of the Relationship of IT Intensity and Organizational Absorptive Capacity on CRM Performance

    OpenAIRE

    Ja-Shen Chen; Russell K.H. Ching

    2004-01-01

    In recent years, e-business has emerged as a mainstream business practice for engaging in global markets. To gain a competitive advantage in these highly competitive markets, many business organizations have turned to customer relationship management (CRM), an integrated system that draws upon the strengths of IT, to allow them to gain greater insights into their customers’ needs. This study examines the relationship of information technology (IT) intensity and organizational absorptive cap...

  17. Atomic structure of machined semiconducting chips: An x-ray absorption spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Paesler, M.; Sayers, D.

    1988-12-01

    X-ray absorption spectroscopy (XAS) has been used to examine the atomic structure of chips of germanium that were produced by single point diamond machining. It is demonstrated that although the local (nearest neighbor) atomic structure is experimentally quite similar to that of single crystal specimens information from more distant atoms indicates the presence of considerable stress. An outline of the technique is given and the strength of XAS in studying the machining process is demonstrated.

  18. A study on maximization of dynamic crushing energy absorption of square tubes with and without stiffener

    OpenAIRE

    Han, Jing; Yamazaki, Koetsu

    2000-01-01

    The axial impact crushing behavior of square tubes with and without stiffeners are studied by Finite Element method, and comparisons of mean axial crushing force between numerical solutions and theoretical prediction as well as qualitative comparisons of folding patterns between numerical simulations and experimental observations are made and discussed. Based on the numerical analyses, maximization problems of dynamic crushing energy absorption of square tubes with and without stiffeners, res...

  19. Refined Study of ECR Wave Propagation and Absorption in the Weakly Relativistic Plasma

    Institute of Scientific and Technical Information of China (English)

    SHIBingren; LONGYongxin

    2001-01-01

    The ECR wave heating is now a routine method for plasma heating and profile control in fusion devices and also in plasma applications. Theoretical study of ECR wave propagation and absorption began very early in 1950's. Basic theoretical work had accomplished in 1970~1980. For toroidal devices like the tokamak, the fundamental O-mode and X-mode with nearly perpendicular propagation were used very often. For pure O-mode and X-mode with kx=O,

  20. Absorption and fluorescence studies of curcumin bound to liposomes and lymphocytes: effect of γ- irradiation

    International Nuclear Information System (INIS)

    Absorption and fluorescence spectral changes in curcumin were employed to follow its binding to liposomes and lymphocytes. The association constants indicated high affinity of curcumin to liposomes. Tumor lymphocytes show mere intense fluorescence of curcumin over the normal lymphocytes. The loss of curcumin in cells after γ-irradiation could be followed by reduction in curcumin fluorescence. The studies indicate that such fluorescence changes can be used as markers to understand the preferential loading of curcumin to cells. (author)

  1. Study on the application of cold vapor atomic absorption spectrometry and hydride generation atomic absorption spectrometry for the determination of Hg and As traces in sea water samples

    International Nuclear Information System (INIS)

    The trace amount of total mercury (Hg) and arsenic (As) in sea water samples were quantitatively determined by using the Atomic Absorption Spectrometry connected with the hydride generation technique (HG-AAS) for As, and with the cold vapour technique (CV-AAS) for Hg. The experiments were carried out at room temperature on a Hydride System Module (HS55) combined with an Atomic Absorption Spectrometer (VARIO 6, Analytik Jena AG). The effect of reductants concentration, and that of matrix on the absorption intensity of each analyzed element was studied in details. The sea water sample after fitrating through a membrane with 0.45(μm-hole size was pre-treated with an oxidant or an reductant to obtain the identical medium. The absorption intensity of each element was then measured on the VARIO-6 under the optimum parameters for spectrometer such as: maximum wavelength, current of hollow cathode lamp, and that for hydride system such as cell temperature, speed of peristaltic pump, pump time, reaction time and rewash time, ect. The analytical procedures were set-up and applied for the determination of these above mentioned elements in the synthesized sea water sample and in the real sea water samples with high precision and accuracy. (author)

  2. Spectrophotometric validation of assay method for selected medicinal plant extracts

    Directory of Open Access Journals (Sweden)

    Matthew Arhewoh

    2014-09-01

    Full Text Available Objective: To develop UV spectrophotometric assay validation methods for some selected medicinal plant extracts.Methods: Dried, powdered leaves of Annona muricata (AM and Andrographis paniculata (AP as well as seeds of Garcinia kola (GK and Hunteria umbellata (HU were separately subjected to maceration using distilled water. Different concentrations of the extracts were scanned spectrophotometrically to obtain wavelengths of maximum absorbance. The different extracts were then subjected to validation studies following international guidelines at the respective wavelengths obtained.Results: The results showed linearity at peak wavelengths of maximum absorbance of 292, 280, 274 and 230 nm for GK, HU, AM and AP, respectively. The calibration curves for the different concentrations of the extract gave R2 values ranging from 0.9831 for AM to 0.9996 for AP the inter-day and intra-day precision study showed that the relative standard deviation (% was ≤ 10% for all the extracts.Conclusion: The aqueous extracts and isolates of these plants can be assayed and monitored using these wavelengths.

  3. Transcutaneous absorption of oil in preterm babies--a pilot study.

    Science.gov (United States)

    Fernandez, A R; Krishnamoorthy, G; Patil, N; Mondkar, J A; Swar, B D

    2005-03-01

    This study was conducted to determine transcutaneous absorption of oil in preterm neonates. A mixture of coconut oil and Meadowfoam oil which contains unique fatty acids, which acted as marker fatty acids was applied to the skin of babies. One mL blood was collected before and one hour after post oil application. Both pre and post oil application serum samples were hydrolysed and derivatised with 2-phenyl hydrazine hydrochloride in order to detect fatty acids by HPLC analysis on C-8 column. None of the pre oil application serum sample showed the presence of the marker fatty acids. The post oil application serum sample of all the 12 babies showed the presence of marker fatty acids of Meadowfoam oil which indicates transcutaneous absorption of oil in preterm babies.

  4. X-ray absorption spectroscopic studies of mononuclear non-heme iron enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Westre, T.E.

    1996-01-01

    Fe-K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the electronic and geometric structure of the iron active site in non-heme iron enzymes. A new theoretical extended X-ray absorption fine structure (EXAFS) analysis approach, called GNXAS, has been tested on data for iron model complexes to evaluate the utility and reliability of this new technique, especially with respect to the effects of multiple-scattering. In addition, a detailed analysis of the 1s{yields}3d pre-edge feature has been developed as a tool for investigating the oxidation state, spin state, and geometry of iron sites. Edge and EXAFS analyses have then been applied to the study of non-heme iron enzyme active sites.

  5. Review of Russian language studies on radionuclide behaviour in agricultural animals: part 1. Gut absorption

    International Nuclear Information System (INIS)

    An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or taken into account in international reviews of gastrointestinal uptake. The paper gives extended information on Russian research on radionuclide absorption in the gut of farm animals performed in controlled field and laboratory experiments from the 1960s to the current time. The data presented in the paper, together with English language values, will be used to provide recommended values of absorption specifically for farm animals within the revision of the IAEA Handbook of Parameter Values IAEA [International Atomic Energy Agency, 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments, IAEA technical reports series No. 364. International Atomic Energy Agency, Vienna

  6. Effect of Atomic Coherence on Absorption in Four-level Systems: an Analytical study

    CERN Document Server

    Sandhya, S N

    2006-01-01

    Absorption profile of a four-level ladder atomic system interacting with three driving fields is studied perturbatively and analytical results are presented. Numerical results where the driving field strengths are treated upto all orders are presented. The absorption features is studied in two regimes, i) the weak middle transition coupling, i.e. $\\Omega_2 \\Omega_{1,3}$ and ii) the strong middle transition coupling $\\Omega_2 \\Omega_{1,3}$. In case i), it is shown that the ground state absorption and the saturation characteristics of the population of level 2 reveal deviation due to the presence of upper level couplings. In particular, the saturation curve for the population of level 2 shows a dip for $\\Omega_1 = \\Omega_3$. While the populations of levels 3 and 4 show a maxima when this resonance condition is satisfied. Thus the resonance condition provides a criterion for maximally populating the upper levels. A second order perturbation calculation reveals the nature of this minima (maxima). In the second ca...

  7. Comparison of Flurbiprofen Tablets Available In Pakistani Market and Their Absorption Studies

    Directory of Open Access Journals (Sweden)

    Muhammad Hanif

    2015-06-01

    Full Text Available AbstractThe aim of this present work was to compare different parameters of various brands of flurbiprofen tablets collected from different retail pharmacies in the local market of Pakistan. Four brands A, B, C and D were tested for weight variation, hardness, friability, disintegration dissolution, HPLC assay and in vitro absorption studies in rabbit skin, stomach and intestine by using the prepacked Column RT 250-4.6 Purospher® STAR RP-18 end capped (5 µm and acetonitrile, phosphate buffer (pH 3.7 as mobile phase in the ratio of 1:1. Flurbiprofen was detected at 265 nm at the flow rate of 1 ml/min. Brand B was considered as reference. Similarity factor (f2 of brand B and C and brand B & D was found to be 61 and 51 and dissimilarity factors (f1 values were 5 and 9 respectively in same dissolution medium. Model dependent methods First order, Hixon crowell and Weibull model were used. The method was found to be sensitive and linear in the range of 10 to 700 ppm with 0.999 coefficient of correlation. Everted sac absorption studies of selected formulation showed 50% of drug absorption from stomach in first 3 hours, 21% through intestine and very negligible through skin.

  8. [Study on experiment of absorption spectroscopy detection of pesticide residues of carbendazim in orange juice].

    Science.gov (United States)

    Ji, Ren-Dong; Chen, Meng-Lan; Zhao, Zhi-Min; Zhu, Xing-Yue; Wang, Le-Xin; Liu, Quan-Jin

    2014-03-01

    Absorption spectra were studied for the carbendazim, in the mixed solution of orange juice and carbendazim using spectrophotometer. The most intensive characteristic peak (285 nm) was found in the spectrum of carbendazim standard solution. Compared with the carbendazim drug solution, the peak position of absorption spectrum has the blue shift (285-280 nm) when carbendazim (0.28 mg x mL(-1))was added in the orange juice. So that we can conclude that interaction happened between the orange juice and carbendazim. Through the method of least squares fitting, the prediction models between the absorbance of orange juice and carbendazim content was obtained with a good linear relationship. The linear function model was: I = 2.41 + 9.26x, the correlation coefficient was 0.996, and the recovery was: 81%-102%. According to the regression model, we can obtain the amount of carbendazim pesticide residues in orange juice. It was verified that the method of using ultraviolet-visible absorption spectra was feasible to detect the carbendazim residues in orange juice. The result proved that it is possible to detect pesticide residues of carbendazim in orange juice, and it can meet the needs of rapid analysis. This study provides a new way for the detection of pesticide residues.

  9. In vitro predictions of skin absorption of caffeine, testosterone, and benzoic acid: A multi-centre comparison study

    NARCIS (Netherlands)

    Sandt, J.J.M. van de; Burgsteden, J.A. van; Cage, S.; Carmichael, P.L.; Dick, I.; Kenyon, S.; Korinth, G.; Larese, F.; Limasset, J.C.; Maas, W.J.M.; Montomoli, L.; Nielsen, J.B.; Payan, J.-P.; Robinson, E.; Sartorelli, P.; Schaller, K.H.; Wilkinson, S.C.; Williams, F.M.

    2004-01-01

    To obtain better insight into the robustness of in vitro percutaneous absorption methodology, the intra- and inter-laboratory variation in this type of study was investigated in 10 European laboratories. To this purpose, the in vitro absorption of three compounds through human skin (9 laboratories)

  10. Titrimetric, spectrophotometric and kinetic methods for the assay of atenolol using bromate–bromide and methyl orange

    Directory of Open Access Journals (Sweden)

    KANAKAPURA BASAVAIAH

    2006-05-01

    Full Text Available Three new methods have been developed for the determination of atenolol in bulk drug and in tablet formulation. The methods are based on the oxidation–bromination reaction of the drug by bromine, generated in situ by the action of acid on a bromate–bromide mixture. In the titrimetric method, the drug is treated with a known excess of bromate–bromide mixture in hydrochloric acid medium, followed by the determination of the unreacted bromine iodometrically. The spectrophotometric method involves the addition of a measured excess of bromate–bromide reagent in hydrochloric acid medium to atenolol, and after ensuring the reaction had gone to completion, the unreacted bromine is treated with a fixed amount of methyl orange, and absorbance measured at 520 nm. The absorbance was found to increase linearly with increasing concentration of atenolol. The kinetic method depends on the existence of a linear relationship between the concentration of the drug and the time of the oxidation–bromination reaction, as indicated by the bleaching of methyl orange acid colour. The working conditions were optimized. The titrimetric method is based on a 1:1 reaction stoichiometry (atenolol:bromate and is applicable over the 3–20 mg range. The spectrophotometric method permits micro determination of the drug (0.5–4.0 mg ml-1with an apparentmolar absorptivity of 4.13x104 lmol-1 cm-1 and detection limit of 0.07 mg ml-1. The kinetic method is applicable in the concentration range 5–25 mg ml-1 with a detection limit of 3.72 mg ml-1. The proposed methods were successfully applied to the determination of atenolol in tablet preparations with mean recoveries of 97.63 to 101.78 %. The reliability of the assay was established by parallel determination by the reference method and by recovery studies using the standard addition technique.

  11. QUANTITATIVE ASSAY OF ALMOTRIPTAN MALATE IN PURE DRUG AND PHARMACEUTICAL PREPARATIONS USING SIMPLE AND CONVENIENT VISIBLE SPECTROPHOTOMETRIC METHODS

    Directory of Open Access Journals (Sweden)

    U. VIPLOVA PRASAD

    2012-05-01

    Full Text Available Two direct, simple and sensitive visible spectrophotometric methods (M1&M2 are described for the assay of almotripan malate in pure and solid dosage forms. The method M1 involves oxidative coupling of drug with brucine in presence of sodium meta periodate and purple red colored species is formed and exhibits absorption maxima at 520nm. The method M2 is based on the formation of yellowish brown colored species by the drug with Folin reagent and exhibits absorption maxima at 450nm. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges (8.0-24 μg/ml for method M1, (16-48 μg/ml for method M2 respectively. The proposed methods are applied to commercial available tablets and the results are statistically compared with those obtained by the reported UV reference method and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the almotriptan malate in the presence of other ingredients that are usually present in dosageforms. These methods offer the advantages of rapidity, simplicity and sensitivity and normal cost and can be easily applied to resource-poor settings without the need for expensive instrumentation and reagents.

  12. Spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from the OSIRIS instrument onboard the ROSETTA spacecraft

    CERN Document Server

    Fornasier, S; Barucci, M A; Feller, C; Besse, S; Leyrat, C; Lara, L; Gutierrez, P J; Oklay, N; Tubiana, C; Scholten, F; Sierks, H; Barbieri, C; Lamy, P L; Rodrigo, R; Koschny, D; Rickman, H; Keller, H U; Agarwal, J; A'Hearn, M F; Bertaux, J -L; Bertini, I; Cremonese, G; Da Deppo, V; Davidsson, B; Debei, S; De Cecco, M; Fulle, M; Groussin, O; Güttler, C; Hviid, S F; Ip, W; Jorda, L; Knollenberg, J; Kovacs, G; Kramm, R; Kührt, E; Küppers, M; La Forgia, F; Lazzarin, M; Moreno, J J Lopez; Marzari, F; Matz, K -D; Michalik, H; Moreno, F; Mottola, S; Naletto, G; Pajola, M; Pommerol, A; Preusker, F; Shi, X; Snodgrass, C; Thomas, N; Vincent, J -B

    2015-01-01

    The Rosetta mission of the European Space Agency has been orbiting the comet 67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort phase. A large complement of scientific experiments designed to complete the most detailed study of a comet ever attempted are onboard Rosetta. We present results for the photometric and spectrophotometric properties of the nucleus of 67P derived from the OSIRIS imaging system, which consists of a Wide Angle Camera (WAC) and a Narrow Angle Camera (NAC). The disk-averaged phase function of the nucleus of 67P shows a strong opposition surge with a G parameter value of -0.13$\\pm$0.01 in the HG system formalism and an absolute magnitude $H_v(1,1,0)$ = 15.74$\\pm$0.02 mag. The integrated spectrophotometry in 20 filters covering the 250-1000 nm wavelength range shows a red spectral behavior, without clear absorption bands except for a potential absorption centered at $\\sim$ 290 nm that is possibly due to SO$_2$ ice. The nucleus shows strong phase reddening, with disk...

  13. Flow-injection Spectrophotometric Determination of Uric Acid in Urine via Prussian Blue Reaction

    Institute of Scientific and Technical Information of China (English)

    WASEEM Amir; YAQOOB Mohammad; NABI Abdul; MURTAZA Ghulam; HUSSAIN Izhar

    2011-01-01

    A simple and sensitive flow injection(FI)spectrophotometric method was reported for the determination of uric acid based on the reduction of Fe(Ⅲ)/ferricyanide in the presence of uric acid.The in situ reduced ions reacted with unreduced portion of ferricyanide/Fe(Ⅲ)to form soluble Prussian blue,which was monitored at an absorption wavelength of 735 nm.The optimized conditions allow a linear calibration graph in a concentration range of 1-100μmol/L.The relative standard deviation was in a range of 0.5%-2.5%,with a detection limit(3σ blank)of 0.3 μmol/L and a sampling frequency of 60 injection/h was obtained.The effect of common substances present in human physiological fluids on the determination of uric acid was examined.The method was applied to determining uric acid in human urine samples with the recoveries in a range of 96%-105%.The results agree well with those by spectrophotometric reference method at a confidence level of 95%.Spectrophotometric procedures for uric acid determination in clinical samples were reviewed briefly.

  14. Polarographic and spectrophotometric determination of Nifuroxazide in pharmaceuticals. II. Determination of Nifuroxazide in suspensions.

    Science.gov (United States)

    Szumińska, E; Cisak, A

    1990-01-01

    The properties of Ercefuryl suspensions which contain Nifuroxazide as active constituent were studied by spectrophotometry and polarography. On this basis two analytical methods for determination of Nifuroxazide content in suspensions were devised: one polarographic, based on the electrochemical reduction of the nitro-group, and a spectrophotometric, based on the absorbance measurements at 373 nm. PMID:12959248

  15. Studies on absorption of EC waves in assisted startup experiment on FTU

    Directory of Open Access Journals (Sweden)

    Ramponi G.

    2012-09-01

    Full Text Available Assistance of EC wave for plasma breakdown and current ramp up is the proposed scenario for the ITER case, characterized by low toroidal electric field. The experimental results on many tokamaks clearly indicate the capabilities of the proposed scheme to have a robust breakdown in ITER. The key aspect of this technique is the EC power required, strongly related to the absorption of the wave in the initial stage of plasma formation. This aspect is generally neglected due to the diagnostics difficulties in the plasma formation phase. As a consequence a multi-pass absorption scheme is usually considered reasonable, leading to a strong absorption after many reflections on the walls. The present study exploits the high temporal and spatial resolution of the fast scanning interferometer of FTU together with the measure of residual power obtained by a sniffer probe. The absorbed EC power is calculated considering also the polarization rotation and the subsequent mode conversion after incidence on the internal wall and compared with that derived from experimental data. The resulting EC power distribution can explain differences observed between perpendicular and oblique injection results, indicating future investigations to define ITER power requirements.

  16. VO2+ ions in zinc lead borate glasses studied by EPR and optical absorption techniques.

    Science.gov (United States)

    Prakash, P Giri; Rao, J Lakshmana

    2005-09-01

    Electron paramagnetic resonance (EPR) and optical absorption spectra of vanadyl ions in zinc lead borate (ZnO-PbO-B2O3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in zinc lead borate glasses were present in octahedral sites with tetragonal compression and belong to C4V symmetry. The spin-Hamiltonian parameters g and A are found to be independent of V2O5 content and temperature but changing with ZnO content. The decrease in Deltag( parallel)/Deltag( perpendicular) value with increase in ZnO content indicates that the symmetry around VO2+ ions is more octahedral. The decrease in intensity of EPR signal above 10 mol% of V2O5 is attributed to a fall in the ratio of the number of V4+ ions (N4) to the number of V5+ ions (N5). The number of spins (N) participating in resonance was calculated as a function of temperature for VO2+ doped zinc lead borate glass sample and the activation energy was calculated. From the EPR data, the paramagnetic susceptibility was calculated at various temperatures and the Curie constant was evaluated from the 1/chi-T graph. The optical absorption spectra show single absorption band due to VO2+ ions in tetragonally distorted octahedral sites. PMID:16043053

  17. Quasar Absorption Lines in the Far Ultraviolet: An Untapped Gold Mine for Galaxy Evolution Studies

    CERN Document Server

    Tripp, Todd

    2013-01-01

    This white paper emphasizes the potential of QSO absorption lines in the rest-frame far/extreme UV at rest-frame wavelengths from ~500 to 2000 A. In this wavelength range, species such as Ne VIII, Na IX, and Mg X can be detected, providing diagnostics of gas with temperatures >> 10^{6} K, as well as banks of adjacent ions such as O I, O II, O III, O IV, O V, and O VI (and similarly N I - N V; S II - S VI; Ne II - Ne VIII, etc.), which constrain physical conditions with unprecedented precision. A UV spectrograph with good sensitivity down to observed wavelengths of 1000 A can detect these new probes in absorption systems with redshift z(abs) > 0.3, and at these redshifts, the detailed relationships between the absorbers and nearby galaxies and large-scale environment can be studied from the ground. By observing QSOs at z = 1.0 - 1.5, HST has started to exploit extreme-UV QSO absorption lines, but HST can only reach a small number of these targets. A future, more sensitive UV spectrograph could open up this new...

  18. X-ray absorption spectral studies of copper (II) mixed ligand complexes

    International Nuclear Information System (INIS)

    X-ray absorption spectra at the K-edge of copper have been studied in two copper mixed ligand complexes, one having tetramethyethylenediamine (tmen) and the other having tetraethyethylenediamine (teen) as one of the ligands. The spectra have been recorded at BL-8 dispersive extended X-ray absorption fine structure (EXAFS) beamline at the 2.5 GeV INDUS- 2 synchrotron, RRCAT, Indore, India. The data obtained has been processed using the data analysis program Athena. The energy of the K-absorption edge, chemical shift, edge-width and shift of the principal absorption maximum in the complexes have been determined and discussed. The values of these parameters have been found to be approximately the same in both the complexes indicating that the two complexes possess similar chemical environment around the copper metal atom. The chemical shift has been utilized to estimate effective nuclear charge on the absorbing atom. The normalized EXAFS spectra have been Fourier transformed. The position of the first peak in the Fourier transform gives the value of first shell bond length, which is shorter than the actual bond length because of energy dependence of the phase factors in the sine function of the EXAFS equation. This distance is thus the phase- uncorrected bond length. Bond length has also been determined by Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The results obtained from LSS and the Fourier transformation methods are comparable with each other, since both are phase uncorrected bond lengths.

  19. EPR, optical absorption and luminescence studies of Cr3+-doped antimony phosphate glasses

    Science.gov (United States)

    De Vicente, F. S.; Santos, F. A.; Simões, B. S.; Dias, S. T.; Siu Li, M.

    2014-12-01

    Antimony phosphate glasses (SbPO) doped with 3 and 6 mol% of Cr3+ were studied by Electron Paramagnetic Resonance (EPR), UV-VIS optical absorption and luminescence spectroscopy. The EPR spectra of Cr3+-doped glasses showed two principal resonance signals with effective g values at g = 5.11 and g = 1.97. UV-VIS optical absorption spectra of SbPO:Cr3+ presented four characteristics bands at 457, 641, 675, and 705 nm related to the transitions from 4A2(F) to 4T1(F), 4T2(F), 2T1(G), and 2E(G), respectively, of Cr3+ ions in octahedral symmetry. Optical absorption spectra of SbPO:Cr3+ allowed evaluating the crystalline field Dq, Racah parameters (B and C) and Dq/B. The calculated value of Dq/B = 2.48 indicates that Cr3+ ions in SbPO glasses are in strong ligand field sites. The optical band gap for SbPO and SbPO:Cr3+ were evaluated from the UV optical absorption edges. Luminescence measurements of pure and Cr3+-doped glasses excited with 350 nm revealed weak emission bands from 400 to 600 nm due to the 3P1 → 1S0 electronic transition from Sb3+ ions. Cr3+-doped glasses excited with 415 nm presented Cr3+ characteristic luminescence spectra composed by two broad bands, one band centered at 645 nm (2E → 4A2) and another intense band from 700 to 850 nm (4T2 → 4A2).

  20. A temperature dependent infrared absorption study of strong hydrogen bonds in bis(glycinium)oxalate

    Science.gov (United States)

    Bhatt, Himal; Deo, M. N.; Murli, C.; Vishwakarma, S. R.; Chitra, R.; Sharma, Surinder M.

    2016-05-01

    We report infrared absorption studies on Bis(glycinium)oxalate, an organic complex of the simplest amino acid Glycine, under varying temperatures in the range 77 - 350 K. The measurements have been carried out in the spectral range 400 - 4000 cm-1 and the strongest O-H---O hydrogen bond, which plays a vital role in the structural stabilization, has been studied. Subtle changes in widths of modes and temperature dependent frequency variations have been observed near 250 K. The hydrogen bonding network remains stable in the entire temperature range. This is in contrast to its reported high pressure behavior.

  1. Spectrophotometric determination of ruthenium using 1-pentyl 4,6-dihydroxy-5-nitrosopyridine-3-carboxylate

    International Nuclear Information System (INIS)

    A method of spectrophotometric analysis for ruthenium, using the reagent 1-pentyl 4,6-dihydroxy-5-nitrosopyridine-3-carboxylate, has been developed. Several interferences are removed by extraction prior to the development of the purple color formed between PDNHPC and ruthenium. The molar absorptivity of the PDHNPC-ruthenium complex is 4.2 x 104 at 535 nm. The complex forms at a 3 : 1 ligand-metal ratio. This procedure provides the most sensitive colorimetric method for the determination of ruthenium. (author)

  2. Determination of Tapentadol Hydrochloride in Tablets by Three New Validated Spectrophotometric Methods

    OpenAIRE

    Deepti Jain; Pawan Kumar Basniwal

    2013-01-01

    Three UV spectrophotometric methods viz. linear regression equation (LRE), standard absorptivity (SA) and first order derivative (FOD) method were developed and validated according to ICH guideline. The methods were linear in the range of 10-50 μg/mL and validated methods were successfully applied for determination of tapentadol hydrochloride content in tablet dosage forms in the range of 100.42-100.64%, 100.31-100.54% and 100.10-100.59%, respectively. The standard deviation for all the metho...

  3. Separate spectrophotometric determination of gadolinium and dysprosium in binary mixtures by phthalexones using nomogram

    International Nuclear Information System (INIS)

    The possibility has been shown of using different-ligand complexes of rare earths with phthalexones and cetylpyridinium for differential spectrophotometric determination of rare earths in mixtures. The molar absorptivities of individual components of a mixture are not constant values if the total mixture concentration changes. The application of an equation for calculation of mixture absorbances makes it possible to change concentration of the components in mixtures over a wide range (the limit Me1:Me2 ratio is 1:50). Simultaneous nomographic determinations of gadolinium and dysprosium in their mixtures were carried out

  4. X-ray absorption spectroscopy and EPR studies of oriented spinach thylakoid preparations

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.C. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States). Structural Biology Div.

    1995-08-01

    In this study, oriented Photosystem II (PS II) particles from spinach chloroplasts are studied with electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) to determine more details of the structure of the oxygen evolving complex (OEC). The nature of halide binding to Mn is also studied with Cl K-edge and Mn EXAFS (extended x-ray absorption fine structure) of Mn-Cl model compounds, and with Mn EXAFS of oriented PS II in which Br has replaced Cl. Attention is focused on the following: photosynthesis and the oxygen evolving complex; determination of mosaic spread in oriented photosystem II particles from signal II EPR measurement; oriented EXAFS--studies of PS II in the S{sub 2} state; structural changes in PS II as a result of treatment with ammonia: EPR and XAS studies; studies of halide binding to Mn: Cl K-edge and Mn EXAFS of Mn-Cl model compounds and Mn EXAFS of oriented Br-treated photosystem II.

  5. Ultrafast transient absorption studies of hematite nanoparticles: the effect of particle shape on exciton dynamics.

    Science.gov (United States)

    Fitzmorris, Bob C; Patete, Jonathan M; Smith, Jacqueline; Mascorro, Xiomara; Adams, Staci; Wong, Stanislaus S; Zhang, Jin Z

    2013-10-01

    Much progress has been made in using hematite (α-Fe2 O3 ) as a potentially practical and sustainable material for applications such as solar-energy conversion and photoelectrochemical (PEC) water splitting; however, recent studies have shown that the performance can be limited by a very short charge-carrier diffusion length or exciton lifetime. In this study, we performed ultrafast studies on hematite nanoparticles of different shapes to determine the possible influence of particle shape on the exciton dynamics. Nanorice, multifaceted spheroidal nanoparticles, faceted nanocubes, and faceted nanorhombohedra were synthesized and characterized by using SEM and XRD techniques. Their exciton dynamics were investigated by using femtosecond transient absorption (TA) spectroscopy. Although the TA spectral features differ for the four samples studied, their decay profiles are similar, which can be fitted with time constants of 1-3 ps, approximately 25 ps, and a slow nanosecond component extending beyond the experimental time window that was measured (2 ns). The results indicate that the overall exciton lifetime is weakly dependent on the shape of the hematite nanoparticles, even though the overall optical absorption and scattering are influenced by the particle shape. This study suggests that other strategies need to be developed to increase the exciton lifetime or to lengthen the exciton diffusion length in hematite nanostructures. PMID:24058060

  6. Gamma camera imaging for studying intestinal absorption and whole-body distribution of selenomethionine

    DEFF Research Database (Denmark)

    Madsen, Jan L.; Sjögreen-Gleisner, Katarina; Elema, Dennis Ringkjøbing;

    2014-01-01

    Se metabolism in humans is not well characterised. Currently, the estimates of Se absorption, whole-body retention and excretion are being obtained from balance and tracer studies. In the present study, we used gamma camera imaging to evaluate the whole-body retention and distribution of radiolab......Se metabolism in humans is not well characterised. Currently, the estimates of Se absorption, whole-body retention and excretion are being obtained from balance and tracer studies. In the present study, we used gamma camera imaging to evaluate the whole-body retention and distribution...... of radiolabelled selenomethionine (SeMet), the predominant form of Se present in foods. A total of eight healthy young men participated in the study. After consumption of a meal containing 4MBq [75Se]L-SeMet ([75Se]SeMet), whole-body gamma camera scanning was performed for 45 min every hour over a 6 h period......]SeMet was retained within the body after 7 d. In contrast, the measured excretion in urine and faeces for the 7 d period was 8•2 (SD 1•1)% of the activity. Time–activity curves were generated for the whole body, stomach, liver, abdomen (other than the stomach and the liver), brain and femoral muscles. Gamma camera...

  7. Spectrophotometric and pH-Metric Studies of Ce(III, Dy(III, Gd(III,Yb(III and Pr(III Metal Complexes with Rifampicin

    Directory of Open Access Journals (Sweden)

    A. N. Sonar

    2011-01-01

    Full Text Available The metal-ligand and proton-ligand stability constant of Ce(III, Dy(III, Gd(III,Yb(III and Pr(III metals with substituted heterocyclic drug (Rifampicin were determined at various ionic strength by pH metric titration. NaClO4 was used to maintain ionic strength of solution. The results obtained were extrapolated to the zero ionic strength using an equation with one individual parameter. The thermodynamic stability constant of the complexes were also calculated. The formation of complexes has been studied by Job’s method. The results obtained were of stability constants by pH metric method is confirmed by Job’s method.

  8. First principle studies on the electronic structures and absorption spectra in KMgF{sub 3} crystal with fluorine vacancy

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Fang [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Liu Tingyu, E-mail: liutyyxj@163.co [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Zhang Qiren; Qiao Hailin; Zhou Xiuwen [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2010-08-01

    The experiments indicate that the perfect KMgF{sub 3} crystal has no absorption in the visible range, however the electron irradiation induces a complex absorption spectrum. The absorption spectra can be decomposed by five Gaussian bands peaking at 2.5 eV (488 nm), 3.4 eV (359 nm), 4.2 eV (295 nm), 4.6 eV (270 nm) and 5.2 eV (239 nm), respectively. The purpose of this paper is to seek the origins of the absorption bands. The electronic structures and absorption spectra either for the perfect KMgF{sub 3} or for KMgF{sub 3}: V{sub F}{sup +} with electrical neutrality have been studied by using density functional theory code CASTEP with the lattice structure optimized. The calculation results predicate that KMgF{sub 3}: V{sub F}{sup +} also exhibits five absorption bands caused by the existence of the fluorine ion vacancy V{sub F}{sup +} and the five absorption bands well coincide with the experimental results. It is believable that the five absorption bands are related to V{sub F}{sup +} in KMgF{sub 3} crystal produced by the electron irradiation.

  9. First principle studies on the electronic structures and absorption spectra in KMgF 3 crystal with fluorine vacancy

    Science.gov (United States)

    Cheng, Fang; Liu, Tingyu; Zhang, Qiren; Qiao, Hailin; Zhou, Xiuwen

    2010-08-01

    The experiments indicate that the perfect KMgF 3 crystal has no absorption in the visible range, however the electron irradiation induces a complex absorption spectrum. The absorption spectra can be decomposed by five Gaussian bands peaking at 2.5 eV (488 nm), 3.4 eV (359 nm), 4.2 eV (295 nm), 4.6 eV (270 nm) and 5.2 eV (239 nm), respectively. The purpose of this paper is to seek the origins of the absorption bands. The electronic structures and absorption spectra either for the perfect KMgF 3 or for KMgF 3: VF+ with electrical neutrality have been studied by using density functional theory code CASTEP with the lattice structure optimized. The calculation results predicate that KMgF 3: VF+ also exhibits five absorption bands caused by the existence of the fluorine ion vacancy VF+ and the five absorption bands well coincide with the experimental results. It is believable that the five absorption bands are related to VF+ in KMgF 3 crystal produced by the electron irradiation.

  10. Synthesis, electrochemical, spectrophotometric and potentiometric studies of two azo-compounds derived from 4-amino-2-methylquinoline in ethanolic-aqueous buffered solutions

    Energy Technology Data Exchange (ETDEWEB)

    El-Attar, Mona A.; Ghoneim, Mohamed M. [Analytical Chemistry Research Unit, Chemistry Department, Tanta University (Egypt); Ismail, Iqbal M., E-mail: maema.2011@yahoo.com [Chemistry Department, Faculty of Science, King Abdul Aziz University, Jeddah (Saudi Arabia)

    2012-08-15

    Two azo-compounds, 2-methyl-4-(5-amino-2-hydroxy-phenylazo)-quinoline (2) and 2-methyl-4-(2-hydroxy-5-nitrophenylazo)-quinoline, derived from 4-amino-2-methylquinoline were synthesized. Their chemical structures were characterized and confirmed by means of elemental chemical analysis, infrared (IR) spectroscopy, {sup 1}H nuclear magnetic resonance (NMR) and mass spectrometry (MS). The electrochemical behavior of the starting compound (4-amino-2-methylquinoline) and of the two synthesized azo-derivatives was studied at the mercury electrode in the B-R universal buffer at various pH values (2-11.5) containing 40% (v/v) ethanol using dc-polarography, cyclic voltammetry and controlled-potential coulometry. Their electrode reaction pathways were elucidated and discussed. The dissociation constants (pKa) of the examined compounds, stability constants and stoichiometry of their complexes in solution with some transition metal ions (Co(II), Ni(II), Cu(II), La(III) and UO{sup 2+}{sub 2}) were determined. (author)

  11. Human in vivo and in vitro studies on gastrointestinal absorption of titanium dioxide nanoparticles.

    Science.gov (United States)

    Jones, Kate; Morton, Jackie; Smith, Ian; Jurkschat, Kerstin; Harding, Anne-Helen; Evans, Gareth

    2015-03-01

    The study was designed to conduct human in vivo and in vitro studies on the gastrointestinal absorption of nanoparticles, using titanium dioxide as a model compound, and to compare nanoparticle behaviour with that of larger particles. A supplier's characterisation data may not fully describe a particle formulation. Most particles tested agreed with their supplied characterisation when assessed by particle number but significant proportions of 'nanoparticle formulations' were particles >100nm when assessed by particle weight. Oral doses are measured by weight and it is therefore important that the weight characterisation is taken into consideration. The human volunteer studies demonstrated that very little titanium dioxide is absorbed gastrointestinally after an oral challenge. There was no demonstrable difference in absorption for any of the three particle sizes tested. All tested formulations were shown to agglomerate in simulated gastric fluid, particularly in the smaller particle formulations. Further agglomeration was observed when dispersing formulations in polymeric or elemental foods. Virtually no translocation of titanium dioxide particles across the cell layer was demonstrated. This study found no evidence that nanoparticulate titanium dioxide is more likely to be absorbed in the gut than micron-sized particles.

  12. High Pressure X-ray Absorption Studies on Correlated-Electron Systems

    Energy Technology Data Exchange (ETDEWEB)

    Cornelius, Andrew L. [Univ. of Nevada, Las Vegas, NV (United States)

    2016-08-26

    Correlated-electron systems are so named because there are strong interactions between electrons unlike traditional metals such as copper that have weakly interacting "free electrons.” Studies on correlated-electron systems have wide ranging interest from defense related issues to future use in nanoscale devices. Experimental results are a necessity for understanding these complicated materials and allow critical tests to theory. We have used high pressure X-ray absorption measurements as a way to estimate the strength of interactions as a function of pressure.

  13. A study on Fresnel absorption and reflections in the keyhole in deep penetration laser welding

    International Nuclear Information System (INIS)

    On the basis of a keyhole photograph obtained experimentally, the keyhole profiles are determined by the method of polynomial fitting. Then the behaviour of the laser beam in the keyhole is analysed by tracing a ray of light using geometrical optics theory; the Fresnel absorption and reflections in the keyhole are systematically studied, and the laser intensities absorbed on the keyhole walls are calculated. By comparing the laser intensity absorbed on the keyhole walls with the heat flux lost there, the mechanism of energy balance on the keyhole walls is discussed. (author)

  14. X-ray scattering and absorption studies of MnAs/GaAs heterostructures

    Science.gov (United States)

    Huang, S.; Ming, Z. H.; Soo, Y. L.; Kao, Y. H.; Tanaka, M.; Munekata, H.

    1996-02-01

    Ferromagnetic MnAs thin films grown on GaAs (001) substrates by molecular-beam epitaxy have been studied by the methods of grazing incidence x-ray scattering, x-ray diffraction, and extended x-ray-absorption fine structure. Microstructures in two films prepared with different first-layer growth conditions (template effects) are compared in terms of the interfacial roughness in the layer structure, lattice constants, epilayer thickness, local environment surrounding the Mn atoms, coordination number, and local disorder. Our results indicate that the template effects can cause significant differences in the local structures and crystallinity of the MnAs epitaxial layers.

  15. X-ray absorption study of tribofilms from ZDDP and overbased salicylate detergents

    Institute of Scientific and Technical Information of China (English)

    Yong Wan; M. Kasrai; G.M. Bancroft

    2009-01-01

    The interaction of overbased salicylate detergents with zinc dialkyldithiophosphates (ZDDP) and its effect on the formation of tribofilms under boundary lubrication have been studied by means of X-ray absorption near-edge structure spectroscopy. The results show that addition of metallic detergents to neat ZDDP results in the change of surface chemistry of the tribofilm formed from neat ZDDP. Calcium from detergents is digested in the tribofilm. For the high overbased detergents, the deposit of overbasing agent CaCO3 in the tribofilm is also observed along with the formation of calcium phosphate in tribofilms.

  16. Catalytic spectrophotometric determination of iodine in coal by pyrohydrolysis decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Wu Daishe [School of Environmental Science and Engineering, Nanchang University, Nanchang 330031 (China); Institute of Geographic Sciences and Resources Research, CAS, Beijing 100101 (China)], E-mail: dswu@ncu.edu.cn; Deng Haiwen [School of Environmental Science and Engineering, Nanchang University, Nanchang 330031 (China); Wang Wuyi [Institute of Geographic Sciences and Resources Research, CAS, Beijing 100101 (China); Xiao Huayun [School of Environmental Science and Engineering, Nanchang University, Nanchang 330031 (China)

    2007-10-10

    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 {mu}g g{sup -1} and 0.29 {mu}g g{sup -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.

  17. Catalytic spectrophotometric determination of iodine in coal by pyrohydrolysis decomposition.

    Science.gov (United States)

    Wu, Daishe; Deng, Haiwen; Wang, Wuyi; Xiao, Huayun

    2007-10-10

    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 microg g(-1) and 0.29 microg 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. PMID:17920390

  18. Spectrophotometric determination of nicradipine and isradipine in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    S. M. Al-Ghannam

    2009-05-01

    Full Text Available A sensitive spectrophotometric method was developed for the determination of some 1,4-dihydropyridine compounds namely, nicardipine and isradipine either in pure form or in pharmaceutical preparations. The method is based on the reduction of nicardipine and isradipine with zinc powder and calcium chloride followed by further reduction with sodium pentacyanoaminoferrate (II to give violet and red products having the absorbance maximum at 546 and 539 nm with nicardipine and isradipine, respectively. Beer’s law was obeyed over the concentration range 8.0–180 μg/ml with the detection limit of 1.67 μg/ml for nicardipine and 8.0–110 μg/ml with the detection limit of 1.748 μg/ml for isradipine. The analytical parameters and their effects on the reported methods were investigated. The molar absorptivity, quantization limit, standard deviation of intercept (Sa, standard deviation of slope (Sb and standard deviation of the residuals (Sy/x were calculated. The composition of the result compounds were found 1:1 for nicardipine and 1:2 for isradipine by Job’s method and the conditional stability constant (Kf and the free energy changes (ΔG were calculated for compounds formed. The proposed method was applied successfully for the determination of nicardipine and isradipine in their dosage forms. The results obtained were in good agreement with those obtained using the reference or official methods. A proposal of the reaction pathway was presented.

  19. Spectrophotometric study of neptunium (VI) complexation by nitrate ions; Etude par spectrophotometrie de la complexation du neptunium au degre d'oxydation (VI) par les ions nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Pochon, P. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification (DRRV), 30 - Marcoule (France)]|[Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)]|[Centre Regional Associe de Lyon, 69 (France)

    2000-07-01

    Neptunium(VI) complexation by nitrate ions was investigated by visible and near-infrared spectrophotometry, a technique suitable for observing the appearance and evolution of the species in solution. In the absence of reference spectra for Np(VI) nitrate- complexes, mathematical (factor analysis) tools were used to interpret the spectra. These chemo-metric techniques were first tested and validated on a simpler chemical system: Np(VI)complexation by the SiW{sub 11}O{sub 39}{sup 8-} anion. The test media used to investigate Np(VI) nitrate- complexes generally contain nitrate and perchlorate salts at high concentrations (high ionic strength). Media effects arising from the presence of cations, acidity or the perchlorate ion concentration are therefore significant, and no doubt account for the scattered values of the complexation constants published in the literature. The evolution of the neptunium spectra according to the parameters of the reaction medium illustrated these effects and allowed them to be quantified by a global 'perturbation constant'. In order to minimize the spectrum modifications due to media effects, the neptunium nitrate-complexes were studied at constant ionic strength in weak acidic media (2 mol.kg{sup -1}{sub H2O}) in the presence of sodium salts. The bulk formation constants and the spectrum of the NpO{sub 2}(NO{sub 3}){sup +} complex were determined for ionic strength values of 2.2, 4, 6 and 8 mol.kg{sup -1}{sub H2O}. The constants remained on the same order of magnitude regardless of the ionic strength; the thermodynamic constant {beta}{sub 1}{sup 0} determined from them according to specific interaction theory is thus probably of little significance. Conversely, the bulk constants can be corrected for the effects of the perchlorate ions by taking the global 'perturbation constant' into account. (author)

  20. [Study of profile analysis on urinary free steroids using high performance liquid chromatography with spectrophotometric scanning by photodiode array--application of Girard reagent T for sample preparation].

    Science.gov (United States)

    Toya, K

    1988-04-20

    High performance liquid chromatography (HPLC) has been useful for profile analysis of steroids. However, the conventional extraction of urinary free steroids using urine specimens has some disadvantages because of lots of interfering substances simultaneously extracted from the urine. These substances were usually detected on the chromatogram at the range of relatively short retention time within which some urinary free steroids were heavily contaminated. Therefore it seemed unsuitable for profile analysis of urinary free steroids by HPLC. In this study, we developed a relatively simple and reproducible method for removing the interfering substances by Girard reagent T. In addition, the purity of each extracted free steroids were confirmed by Photodiode Array continuous scanning system, together with 3-dimensional chromatogram as well as contour map analyzed by the attached computer. The extraction procedure was as follows: (1) 10% volume of 24-h specimens of urine included 1 microgram internal standard was charged to Sep-pack C18 cartridge. The cartridge was eluted with 20 micromilligram ethyl acetate and the eluate was evaporated. (2) 10 mg Girard reagent T dissolved in 0.5 micromilligram acetic acid and 0.5 micromilligram ethanol was added to the residue, then left at room temperature for 2 hours. During this time, ketosteroids formed by the action of Girard reagent T turned to be water-soluble hydrazone complex. (3) After the addition of 10 micromilligram cold water, it was adjusted to pH 8 with NaOH and NaHCO3, then washed with 5 volumes of ethyl acetate (non-ketotic fraction). (4) The lower layer were hydrolyzed by adding 0.5 micromilligram concentrated hydrogen chloride and left for an hour at room temperature, then the liberated steroids were extracted with ethyl acetate (ketotic fraction). (5) Ethyl acetate extract was evaporated and redissolved in the mobile phase, then injected to HPLC. To determine the effect of Girard's separation non-ketotic fraction

  1. Sonochemical assisted hydrothermal synthesis of ZnO: Cr nanoparticles loaded activated carbon for simultaneous ultrasound-assisted adsorption of ternary toxic organic dye: Derivative spectrophotometric, optimization, kinetic and isotherm study.

    Science.gov (United States)

    Jamshidi, M; Ghaedi, M; Dashtian, K; Hajati, S; Bazrafshan, A A

    2016-09-01

    Chromium doped zinc oxide nanoparticles (ZnO: Cr-NPs) was synthesized by ultrasonically assisted hydrothermal method and characterized by FE-SEM, XRD and TEM analysis. Subsequently, this composite ultrasonically assisted was deposited on activated carbon (ZnO: Cr-NPs-AC) and used for simultaneous ultrasound-assisted removal of three toxic organic dye namely of malachite green (MG), eosin yellow (EY) and Auramine O (AO). Dyes spectra overlap in mixture (major problem for simultaneous investigation) of this systems was extensively resolved by derivative spectrophotometric method. The magnitude of variables like initial dyes concentration, adsorbent mass and sonication time influence on dyes removal was optimized using small central composite design (CCD) combined with desirability function (DF) approach, while pH was studied by one-a-time approach. The maximized removal percentages at desirability of 0.9740 was set as follow: pH 6.0, 0.019g ZnO: Cr-NPs-AC, 3.9min sonication at 4.5, 4.8 and 4.7mgL(-1) of MG, EY and AO, respectively. Above optimized points lead to achievement of removal percentage of 98.36%, 97.24%, and 99.26% correspond to MG, EY and AO, respectively. ANOVA for each dyes based p-value less than (removal of these dyes within 95% confidence interval, while their F-value for MG, EY and AO is 935, 800.2, and 551.3, respectively, that confirm low participation of this them in signal. The value of multiple correlation coefficient R(2), adjusted and predicted R(2) for simultaneous removal of MG is 0.9982, 0.9972 and 0.9940, EY is 0.9979, 0.9967 and 0.9930 and for AO is 0.9970, 0.9952 and 0.9939. The adsorption rate well fitted by pseudo second-order and Langmuir model via high, economic and profitable adsorption capacity of 214.0, 189.7 and 211.6mgg(-1) for MG, EY and AO, respectively. PMID:27150752

  2. A study on radon absorption efficiencies of edible oils produced in India.

    Science.gov (United States)

    Karunakara, N; Al-Azmi, Darwish

    2010-04-01

    A study on absorption of radon by different edible oils of plant origins produced and used in India was conducted in order to identify efficient radon-absorbing oils. A comparative study of radon absorption by edible oils of India with that of olive oil, which is known as a good absorber of radon, was also carried out. The study was performed by bubbling known concentrations of radon through the oil contained in a bottle and then evaluating the bubbled oil by gamma-ray spectrometry using an HPGe detector. The results show that oils such as coconut oil, gingelly oil (till oil), ground nut oil, mustard oil, sunflower oil, and saffola kardi oil are also good absorbers for radon, and among them coconut oil and gingelly oils are better absorbers than olive oil. The Henry's equilibrium constant (or the concentration factor), an indicator for the solubility of gas in liquids, was also measured for different types of oil by saturating a known volume of the oil with radon. The Henry's equilibrium constant varied in the range 7.32-8.22 for the Indian vegetable oils, and for olive oil it was found to be 7.88. The details of the experimental technique employed and results obtained are presented and discussed in this paper.

  3. Characterization on the Mean Molar Absorptivity of Amino Acids in Microbial Lipopeptides

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid composition exactly equivalent to that of the peptide chain of the corresponding lipopeptide were determined based on calculation or experimental. The significance of the results is that the mean molar absorption coefficients strongly demonstrate the regular patterns, though different amino acids bear quite different molar absorption coefficients.

  4. Spectrophotometric determination of etodolac in pure form and pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Gouda Ayman A

    2008-04-01

    Full Text Available Abstract Background Etodolac (ETD is a non-steroidal anti-inflamatory antirheumatic drug. A survey of the literature reveals that there is no method available for the determination of ETD in pure form and pharmaceutical formulations by oxidation-reduction reactions. Results We describe three simple, sensitive and reproducible spectrophotometric assays (A-C for the determination of etodolac in pure form and in pharmaceutical formulations. Methods A and B are based on the oxidation of etodolac by Fe3+ in the presence of o-phenanthroline (o-phen or bipyridyl (bipy. The formation of the tris-complex on reaction with Fe3+-o-phen and/or Fe3+-bipy mixtures in acetate buffer solution at optimum pH was demonstrated at 510 and 520 nm with o-phen and bipy. Method C is based on the oxidation of etodolac by Fe3+ in acidic medium, and the subsequent interaction of iron(II with ferricyanide to form Prussian blue, with the product exhibiting an absorption maximum at 726 nm. The concentration ranges are 0.5–8, 1.0–10 and 2–18 μg mL-1 respectively for methods A, B and C. For more accurate analysis, Ringbom optimum concentration ranges were calculated, in addition to molar absorptivity, Sandell sensitivity, detection and quantification limits. Conclusion Our methods were successfully applied to the determination of etodolac in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were ≤ 0.76 %, with recoveries of 99.87 % – 100.21 %.

  5. Non-destructive studies of fuel pellets by neutron resonance absorption radiography and thermal neutron radiography

    International Nuclear Information System (INIS)

    Many isotopes in nuclear materials exhibit strong peaks in neutron absorption cross sections in the epithermal energy range (1–1000 eV). These peaks (often referred to as resonances) occur at energies specific to particular isotopes, providing a means of isotope identification and concentration measurements. The high penetration of epithermal neutrons through most materials is very useful for studies where samples consist of heavy-Z elements opaque to X-rays and sometimes to thermal neutrons as well. The characterization of nuclear fuel elements in their cladding can benefit from the development of high resolution neutron resonance absorption imaging (NRAI), enabled by recently developed spatially-resolved neutron time-of-flight detectors. In this technique the neutron transmission of the sample is measured as a function of spatial location and of neutron energy. In the region of the spectra that borders the resonance energy for a particular isotope, the reduction in transmission can be used to acquire an image revealing the 2-dimensional distribution of that isotope within the sample. Provided that the energy of each transmitted neutron is measured by the neutron detector used and the irradiated sample possesses neutron absorption resonances, then isotope-specific location maps can be acquired simultaneously for several isotopes. This can be done even in the case where samples are opaque or have very similar transmission for thermal neutrons and X-rays or where only low concentrations of particular isotopes are present (<0.1 atom% in some cases). Ultimately, such radiographs of isotope location can be utilized to measure isotope concentration, and can even be combined to produce three-dimensional distributions using tomographic methods. In this paper we present the proof-of-principle of NRAI and transmission Bragg edge imaging performed at Flight Path 5 (FP5) at the LANSCE pulsed, moderated neutron source of Los Alamos National Laboratory. A set of urania mockup

  6. In vitro study of transporters involved in intestinal absorption of inorganic arsenic.

    Science.gov (United States)

    Calatayud, Marta; Barrios, Julio A; Vélez, Dinoraz; Devesa, Vicenta

    2012-02-20

    Inorganic arsenic (iAs) [As(III)+As(V)] is a drinking water contaminant, and human exposure to these arsenic species has been linked with a wide range of health effects. The main path of exposure is the oral route, and the intestinal epithelium is the first physiological barrier that iAs must cross in order to be absorbed. However, there is a lack of information about intestinal iAs absorption. The aim of this study was to evaluate the participation of certain transporters [glucose transporters (GLUT and SGLT), organic anion transporting polypeptides (OATPs), aquaporins (AQPs), and phosphate transporters (NaPi and PiT)] in intestinal absorption of As(V) and As(III), using the Caco-2 cell line as a model of the intestinal epithelium. For this purpose, the effects of chemical inhibition and gene silencing of the transporters of interest on iAs uptake were evaluated, and also the differential expression of these transporters after treatment with iAs. The results show that chemical inhibition using rifamycin SV (OATP inhibitor), phloridzin (SGLT inhibitor), phloretin (GLUT and AQP inhibitor), and copper sulfate (AQP inhibitor) leads to a significant reduction in the apparent permeability and cellular retention of As(III). RT-qPCR indicates up-regulation of GLUT2, GLUT5, OATPB, AQP3, and AQP10 after exposure to As(III), while exposure to As(V) increases the expression of sodium-dependent phosphate transporters, especially NaPiIIb. Gene silencing of OATPB, AQP10, and GLUT5 for As(III) and NaPiIIb for As(V) significantly reduces uptake of the inorganic forms. These results indicate that these transporters may be involved in intestinal absorption of iAs.

  7. Spectrophotometric determination of nateglinide in bulk and tablet dosage forms

    Directory of Open Access Journals (Sweden)

    Jain Suresh

    2009-01-01

    Full Text Available Nateglinide (NTG is available as tablet dosage form in 60 mg and 120 mg strength. In the present study, two simple, reproducible and efficient UV spectrophotometric methods for the estimation of this drug in bulk and pharmaceutical dosage forms have been developed. In method I, methanol-AR was used as solvent, while in method II, Methanol-AR + 10% V/V 3N NaOH was used as reference solvent. In method I, nateglinide shows λmax at 216 nm, which is then shifted to 225.4 nm on increasing the basicity of the reference solvent in method II. The linearity for nateglinide was observed to be statistically in the range of 10-100 μg/ml in method I and 100-1000 μg/ml in method II. Both the methods were validated using ANOVA. The recovery studies confirmed the accuracy of the proposed methods.

  8. A rapid spectrophotometric method for the determination of mercury in environmental, biological, soil and plant samples using diphenylthiocarbazone

    OpenAIRE

    AHMED, M. Jamaluddin; Alam, Md Shah

    2003-01-01

    A simple, sensitive and highly selective direct spectrophotometric method for the determination of trace levels of mercury(II) in various samples is described. Diphenylthiocarbazone (dithizone) reacts in slightly acidic 50% aqueous 1,4-dioxane media (0.18–1.80 M sulphuric acid) with mercury(II) to give an orange chelate which has an absorption maximum at 488 nm. The average molar absorption co-efficient and Sandell's sensitivity were found to be 2.5×104l mol−1 cm−1 and 0.015 μg of Hg(II) cm−2...

  9. Highly sensitive catalytic spectrophotometric determination of ruthenium

    Science.gov (United States)

    Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

    2008-01-01

    A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

  10. X-ray absorption Studies of Zinc species in Centella asiatica

    Science.gov (United States)

    Dehipawala, Sunil; Cheung, Tak; Hogan, Clayton; Agoudavi, Yao; Dehipawala, Sumudu

    2013-03-01

    Zinc is a very important mineral present in a variety of vegetables. It is an essential element in cellular metabolism and several bodily functions. We used X-ray fluorescence, and X-ray Absorption near Edge structure(XANES) to study the amount of zinc present in several leafy vegetables as well as its chemical environment within the plant. Main absorption edge position of XANES is sensitive to the oxidation state of zinc and is useful when comparing the type of zinc present in different vegetables to the standard zinc present in supplements. Normalized main edge height is proportional to the amount of zinc present in the sample. Several leafy greens were used in this study, such as Spinacia oleracea, Basella alba, Brassica oleracea, Cardiospermum halicacabumand Centella asiatica. All of these plant leaves contained approximately the same amount of zinc in the leaf portion of the plant and a slightly lower amount in the stems, except Centella asiatica. Both leaves and stems of the plant Centella asiatica contained nearly two times the zinc compared to other plants. Further investigation of zinc's chemical environment within Centella asiatica could lead to a much more efficient dietary consumption of zinc. Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886

  11. In Situ X-Ray Absorption Spectroscopy Study of the LiNiO2 Electrode

    Science.gov (United States)

    Mansour, A. N.; McBreen, J.; Melendres, C. A.

    1997-03-01

    LiNiO2 is one of the most promising active material for the development of novel 4V rechargeable lithium batteries. Recent x-ray diffraction studies showed that the electrochemical reactivity of this electrode is sensitive to the structure of the starting material as well as the charged products. To further examine this material, we have conducted an x-ray absorption spectroscopy (XAS) study to determine the structure of this electrode as a function of its charge state. Specifically, the x-ray absorption Ni K-edge energy, the pre-edge structure, and local structure parameters such as bond lengths, coordination numbers and disorders were investigated at various states of charge corresponding to Li_(1-x)NiO2 for x values of 0.0, 0.11, 0.23, 0.34, 0.45, 0.82, and 0.99. The charging which proceeds via lithium de-intercalation was conducted using constant current anodization at 0.5 mA in a non aqueous electrolyte consisting of 1M LiPF6 in 1:1:3 propylene ! carbonate, ethylene carbonate and dimethyl carbonate. The XAS results for this electrode will be compared with those of γ-NiOOH and KNiIO_6, the latter being used as a reference for quadrivalent nickel.

  12. Theoretical studies on the one- and two-photon absorption properties of azulenylporphyrins and azulene-fused porphyrins

    Institute of Scientific and Technical Information of China (English)

    Li Wen-Chao; Feng Ji-Kang; Ren Ai-Min; Zhang Xiang-Biao; Sun Jia-Zhong

    2009-01-01

    The electronic structures, one-photon absorption (OPA) and two-photon absorption (TPA) properties of the azulenylporphyrins and azulene-fused porphyrins have been comparatively studied by using DFT/B3LYP/6-31G(d)and the ZINDO/SDCI method. With the number of azulenyl groups increasing, the OPA wavelengths of all molecules are red-shifted in 400-600 nm and the two-photon absorption cross section is gradually enlarged. The azulene-fused structures facilitate an expanding conjugated area and increasing TPA cross section. The origin of TPA properties of studied compounds is studied with a two-level model. In summary, the azulene-fused porphyrins exhibit strong two-photon absorption.

  13. Atomic Transition Frequencies, Isotope Shifts, and Sensitivity to Variation of the Fine Structure Constant for Studies of Quasar Absorption Spectra

    Science.gov (United States)

    Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.; King, J. A.; Kozlov, M. G.; Murphy, M. T.; Webb, J. K.

    Theories unifying gravity with other interactions suggest spatial and temporal variation of fundamental "constants" in the Universe. A change in the fine structure constant, α = {e}2/hslash c , could be detected via shifts in the frequencies of atomic transitions in quasar absorption systems. Recent studies using 140 absorption systems from the Keck telescope and 153 from the Very Large Telescope, suggest that α varies spatially (61). That is, in one direction on the sky α seems to have been smaller at the time of absorption, while in the opposite direction it seems to have been larger.

  14. Study of the influence on radiation, chemical and thermic treatment in Cesium and Cobalt absorption in natural zeolites

    International Nuclear Information System (INIS)

    The influence of radiation and thermic treatment of zeolites from El Piojillo (Villa Clara), Orozco (Pinar del Rio) and Palmarito (Santiago de Cuba) deposits in the absorption of cesium-137 is studied. It was verified that as it generally occurs in zeolites, the thermic treatment influences negatively the absorption and the radiation treatment with dose up to 105 Gy does not affect it. Alternatives to chemical and chemical-thermic treatment for zeolite from El Piojillo are also applied. It was noted that previous treatment with NH4OH at 2000C in the vacuum stove and its contact in dynamic regime with NaNO3 improves its capacity of cobalt absorption

  15. An electron microscopic study of the intestinal villus. II. The pathway of fat absorption.

    Science.gov (United States)

    PALAY, S L; KARLIN, L J

    1959-05-25

    The intestinal pathway for absorbed fat was traced in thin sections of intestinal villi from rats fed corn oil by stomach tube after a fast of 24 to 40 hours. For electron microscopy the tissues were fixed in chilled buffered osmium tetroxide and embedded in methacrylate. For light microscopy, other specimens from the same animals were fixed in formal-calcium, mordanted in K(2)Cr(2)O(7), and embedded in gelatin. Frozen sections were stained with Sudan black B or Sudan IV. About 20 minutes after feeding, small fat droplets (65 mmicro maximal diameter) appear in the striated border between microvilli. At the same time fat particles are seen within pinocytotic vesicles in the immediately subjacent terminal web. In later specimens the fat droplets are generally larger (50 to 240 mmicro) and lie deeper in the apical cytoplasm. All intracellular fat droplets are loosely enveloped in a thin membrane, the outer surface of which is sometimes studded with the fine particulate component of the cytoplasm. This envelope, apparently derived from the cell surface by pinocytosis, has at this stage evidently become a part of the endoplasmic reticulum. Just above the nucleus numerous fat droplets lie clustered within the dilated cisternae of the Golgi complex. As absorption progresses fat droplets appear in the intercellular spaces of the epithelium, in the interstitial connective tissue spaces of the lamina propria, and in the lumen of the lacteals. All of these extracellular fat droplets are devoid of a membranous envelope. The picture of fat absorption as reconstructed from these studies involves a stream of fat droplets filtering through the striated border, entering the epithelial cell by pinocytosis at the bases of the intermicrovillous spaces, and coursing through the endoplasmic reticulum to be discharged at the sides of the epithelial cell into extracellular spaces. From the epithelial spaces, the droplets move into the lamina propria and thence into the lymph. If the lumen

  16. Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, J. Matthew; Cullinan, Valerie I.; Barnett, Debra S.; Trang-Le, Truc LT; Bliss, Mary; Greenwood, Lawrence R.; Ballinger, Marcel Y.

    2009-02-17

    effects. The microscopy analysis compares different filter loadings and shows that smaller particle sizes (under 10 micron) can readily be seen on the more lightly loaded filters. At higher loadings, however, the particle size is harder to differentiate. This study provides data on actual stack emission samples showing a range of mass loading conditions and visual evidence of particle size and distribution and also presents the difficulties in quantifying self-absorption effects using actual samples.

  17. Resolution of overlapped spectra for the determination of ternary mixture using different and modified spectrophotometric methods

    Science.gov (United States)

    Moussa, Bahia Abbas; El-Zaher, Asmaa Ahmed; Mahrouse, Marianne Alphonse; Ahmed, Maha Said

    2016-08-01

    Four new spectrophotometric methods were developed, applied to resolve the overlapped spectra of a ternary mixture of [aliskiren hemifumarate (ALS)-amlodipine besylate (AM)-hydrochlorothiazide (HCT)] and to determine the three drugs in pure form and in combined dosage form. Method A depends on simultaneous determination of ALS, AM and HCT using principal component regression and partial least squares chemometric methods. In Method B, a modified isosbestic spectrophotometric method was applied for the determination of the total concentration of ALS and HCT by measuring the absorbance at 274.5 nm (isosbestic point, Aiso). On the other hand, the concentration of HCT in ternary mixture with ALS and AM could be calculated without interference using first derivative spectrophotometric method by measuring the amplitude at 279 nm (zero crossing of ALS and zero value of AM). Thus, the content of ALS was calculated by subtraction. Method C, double divisor first derivative ratio spectrophotometry (double divisor 1DD method), was based on that for the determination of one drug, the ratio spectra were obtained by dividing the absorption spectra of its different concentrations by the sum of the absorption spectra of the other two drugs as a double divisor. The first derivative of the obtained ratio spectra were then recorded using the appropriate smoothing factor. The amplitudes at 291 nm, 380 nm and 274.5 nm were selected for the determination of ALS, AM and HCT in their ternary mixture, respectively. Method D was based on mean centering of ratio spectra. The mean centered values at 287, 295.5 and 269 nm were recorded and used for the determination of ALS, AM and HCT, respectively. The developed methods were validated according to ICH guidelines and proved to be accurate, precise and selective. Satisfactory results were obtained by applying the proposed methods to the analysis of pharmaceutical dosage form.

  18. Femtosecond Transient Absorption Studies in Cadmium Selenide Nanocrystal Thin Films Prepared by Chemical Bath Deposition Method

    Directory of Open Access Journals (Sweden)

    M. C. Rath

    2007-01-01

    Full Text Available Dynamics of photo-excited carrier relaxation processes in cadmium selenide nanocrystal thin films prepared by chemical bath deposition method have been studied by nondegenerate femtosecond transient pump-probe spectroscopy. The carriers were generated by exciting at 400 nm laser light and monitored by several other wavelengths. The induced absorption followed by a fast bleach recovery observed near and above the bandgap indicates that the photo-excited carriers (electrons are first trapped by the available traps and then the trapped electrons absorb the probe light to show a delayed absorption process. The transient decay kinetics was found to be multiexponential in nature. The short time constant, <1 picosecond, was attributed to the trapping of electrons by the surface and/or deep traps and the long time constant, ≥20 picoseconds, was due to the recombination of the trapped carriers. A very little difference in the relaxation processes was observed in the samples prepared at bath temperatures from 25∘C to 60∘C.

  19. Resonant inverse photoemission study of late transition metals at 3p absorption edge

    International Nuclear Information System (INIS)

    Full text: Resonant inverse photoemission spectra (RIPES) of late transition metals (TM) were observed near TM 3p absorption edge. The RIPES spectra of polycrystalline Co, Ni and Cu, as well as single crystal Ni, were observed. Figure 1 shows resonant IPES spectra of polycrystalline Co, Ni and Cu, which were prepared by evaporation. These spectra ware excited by energy above 3p absorption edge (off-resonance). Since a core hole is created by these energies, TM 3d → 3p fluorescence peak is observed in each spectrum at high energy, which is indicated by vertical bars. The main peak just above EF is TM 3d structure, while TM 4sp is observed at 10 ∼ 15 eV. In resonant spectra, the 3d structure changes its intensity, while the 4sp structure does not. In case of Ni metal, satellite structures are also observed at about 2 and 4 eV. From a calculation by Tanaka and Jo, which is based on the Anderson impurity model, the observation of satellite structures suggests the 10 ∼ 20 % 3d8 in ground state The RIPES spectra in this study give us a direct evidence of 3d8 component in Ni metal

  20. Enhanced oral absorption of insulin-loaded liposomes containing bile salts: a mechanistic study.

    Science.gov (United States)

    Niu, Mengmeng; Tan, Ya'nan; Guan, Peipei; Hovgaard, Lars; Lu, Yi; Qi, Jianping; Lian, Ruyue; Li, Xiaoyang; Wu, Wei

    2014-01-01

    Liposomes containing bile salts (BS-liposomes) significantly enhanced the oral bioavailability of insulin (rhINS). However, the underlying absorption mechanisms have not been well understood yet. In this study, the transiting fate of the liposomes was first investigated using fluorescent imaging tools to confirm the effect of enhanced gastrointestinal stability. In order to obtain evidence of enhanced transcellular permeation, the interaction between BS-liposomes and the biomembrane was investigated in Caco-2 cell lines. BS-liposomes were found to be more stable in the gastrointestinal tract by showing prolonged residence time in comparison with conventional liposomes. BS-liposomes were significantly more effective for cellular uptake and transport of rhINS; and this effect was found to be size- and concentration-dependent. A good linear correlation was observed between the concentration of the liposomes and uptake/transport of rhINS. Confocal laser scanning microscopy visualization further validated the transcellular transit of BS-liposomes. The BS-liposomes showed little effect on cytotoxicity and did not induce apoptosis within 24h investigation. It was concluded that BS-liposomes showed improved in vivo residence time and enhanced permeation across the biomemebranes. Mechanisms of trans-enterocytic internalization could be proposed as an interpretation for enhanced absorption of insulin-loaded liposomes.

  1. EPR and optical absorption studies of VO2+ ions in alkaline earth aluminoborate glasses

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance (EPR) and optical absorption studies have been carried out for VO2+ ions in calcium aluminoborate glasses. The EPR spectra of all the glass samples exhibit resonance signals, characteristic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in calcium aluminoborate glasses were present in octahedral co-ordination with a tetragonal compression and belong to C4v symmetry. The number of spins (N) participating in resonance was calculated as a function of concentration as well as temperature. It is observed that variation of N with temperature obeys the Boltzmann law. From the EPR data, the paramagnetic susceptibility (χ) is calculated at various temperatures and the Curie constant (C) was evaluated from the 1/χ-T graph. The Fermi contact interaction parameter (k), dipolar hyperfine coupling parameter (P) have been calculated and these values are found to be independent of V2O5 content and temperature. The optical absorption spectrum exhibits two bands corresponding to the d-d transition 2B2g → 2Eg and 2B2g → 2A1g in the order of increasing energy. The theoretical values of optical basicity (Λth) of the glasses have also been evaluated

  2. X-ray absorption studies of graphite intercalates and metal-ammonia solutions

    International Nuclear Information System (INIS)

    X-ray absorption spectroscopy (XAS) was used to study the arsenic fluorocomplexes, including the AsF5 and AsF6- intercalates of graphite, and rubidium metal-ammonia solutions. The As-F distances obtained for AsF3 and AsF5 gas are both in excellent agreement with electron diffraction data (within 0.004 A). A superior measurement which is significantly shorter than the accepted value of the bond distance in an undistorted AsF6- octahedra is reported. Both the XAES and EXAFS data presented support the hypothesis that the AsF5 oxidizes graphite upon intercalation to produce AsF6- and AsF3 intercalant species. Changes in the Rb K-edge features which are consistent with the known properties of Rb-NH3 are correlated with conductivity and delocalization of the solvated electrons. In the XAES region, intensity and position changes of absorption transitions are explained. In the EXAFS region, the Rb-N bond distance and the relative number of nitrogen atoms in the first shell are measured. XAS has been shown to provide unique information about the nature of the metal-ammonia phase separation, phase transition, and density fluctuations

  3. [Study on Differential Optical Absorption Spectroscopy Data Processing Based on Chirp-Z Transformation].

    Science.gov (United States)

    Zheng, Hai-ming; Li, Guang-jie; Wu, Hao

    2015-06-01

    Differential optical absorption spectroscopy (DOAS) is a commonly used atmospheric pollution monitoring method. Denoising of monitoring spectral data will improve the inversion accuracy. Fourier transform filtering method is effectively capable of filtering out the noise in the spectral data. But the algorithm itself can introduce errors. In this paper, a chirp-z transform method is put forward. By means of the local thinning of Fourier transform spectrum, it can retain the denoising effect of Fourier transform and compensate the error of the algorithm, which will further improve the inversion accuracy. The paper study on the concentration retrieving of SO2 and NO2. The results show that simple division causes bigger error and is not very stable. Chirp-z transform is proved to be more accurate than Fourier transform. Results of the frequency spectrum analysis show that Fourier transform cannot solve the distortion and weakening problems of characteristic absorption spectrum. Chirp-z transform shows ability in fine refactoring of specific frequency spectrum. PMID:26601381

  4. Particle extinction measured at ambient conditions with differential optical absorption spectroscopy. 2. Closure study.

    Science.gov (United States)

    Müller, Thomas; Müller, Detlef; Dubois, René

    2006-04-01

    Spectral particle extinction coefficients of atmospheric aerosols were measured with, to the best of our knowledge, a newly designed differential optical absorption spectroscopy (DOAS) instrument. A closure study was carried out on the basis of optical and microphysical aerosol properties obtained from nephelometer, particle soot/absorption photometer, hygroscopic tandem differential mobility analyzer, twin differential mobility particle sizer, aerodynamic particle sizer, and Berner impactors. The data were collected at the urban site of Leipzig during a period of 10 days in March 2000. The performance test also includes a comparison of the optical properties measured with DOAS to particle optical properties calculated with a Mie-scattering code. The computations take into account dry and ambient particle conditions. Under dry particle conditions the linear regression and the correlation coefficient for particle extinction are 0.95 and 0.90, respectively. At ambient conditions these parameters are 0.89 and 0.97, respectively. An inversion algorithm was used to retrieve microphysical particle properties from the extinction coefficients measured with DOAS. We found excellent agreement within the retrieval uncertainties. PMID:16607998

  5. Time-resolved X-ray Absorption Spectroscopy for Electron Transport Study in Warm Dense Gold

    Science.gov (United States)

    Lee, Jong-Won; Bae, Leejin; Engelhorn, Kyle; Heimann, Philip; Ping, Yuan; Barbrel, Ben; Fernandez, Amalia; Beckwith, Martha Anne; Cho, Byoung-Ick; GIST Team; IBS Team; LBNL Collaboration; SLAC Collaboration; LLNL Collaboration

    2015-11-01

    The warm dense Matter represents states of which the temperature is comparable to Fermi energy and ions are strongly coupled. One of the experimental techniques to create such state in the laboratory condition is the isochoric heating of thin metal foil with femtosecond laser pulses. This concept largely relies on the ballistic transport of electrons near the Fermi-level, which were mainly studied for the metals in ambient conditions. However, they were barely investigated in warm dense conditions. We present a time-resolved x-ray absorption spectroscopy measured for the Au/Cu dual layered sample. The front Au layer was isochorically heated with a femtosecond laser pulse, and the x-ray absorption changes around L-edge of Cu, which was attached on the backside of Au, was measured with a picosecond resolution. Time delays between the heating of the `front surface' of Au layer and the alternation of x-ray spectrum of Cu attached on the `rear surface' of Au indicate the energetic electron transport mechanism through Au in the warm dense conditions. IBS (IBS-R012-D1) and the NRF (No. 2013R1A1A1007084) of Korea.

  6. Simple spectrophotometric methods for quantification of modafinil us-ing 1,2-naphthoquinone-4-sulphonate and 2,4-dinitrophenol as analyti-cal reagents

    Directory of Open Access Journals (Sweden)

    Burla Sunitha Venkata Seshamamba

    2014-10-01

    Full Text Available Two simple visible spectrophotometric methods are developed and validated for the quantifica-tion of modafinil using 1,2-naphthoquinone-4-sulphonic acid (NQS method and 2,4-dinitrophenol (DNP method as analytical reagents. The NQS method involves the reaction of modafinil with 1,2-naphthoquinone-4-sulphonate in alkaline medium at room conditions to form a yellow colored product exhibiting maximum absorption at 430 nm. DNP method is based on the proton transfer from 2,4-dinitrophenol to modafinil at room conditions and then we have the formation of yellow colored ion-pair complex exhibiting maximum absorption at 475 nm. Dif-ferent variables affecting the reaction were studied and optimized. Under the optimized experi-mental conditions, Beer's law is obeyed in the concentration ranges of 10-100 and 8-60 μg/mL with the detection of limit values of 0.486 and 0.258 μg/mL for NQS method and DNP method, respectively The molar absorptivity and Sandell's sensitivity for both of the methods are report-ed. The methods were validated in terms of accuracy, precision and robustness. The results were satisfactory. The proposed methods were effectively applied to the analysis of the modafinil in their tablet formulations. The recoveries were 99.92% and 99.96% with RSD and 0.863% and 0.722% for NQS and DNS methods, respectively. The assay was not interfered by common ex-cipients.

  7. Optical Spectrophotometric Monitoring of Fermi/LAT Bright Sources

    CERN Document Server

    Patiño-Álvarez, V; León-Tavares, J; Valdés, J R; Carramiñana, A; Carrasco, L; Torrealba, J

    2013-01-01

    We describe an ongoing optical spectrophotometric monitoring program of a sample of Fermi/LAT bright sources showing prominent and variable {\\gamma}-ray emission, with the 2.1m telescope at Observatorio Astrof\\'isico Guillermo Haro (OAGH) located in Cananea, Sonora, M\\'exico. Our sample contains 11 flat spectrum radio quasars (FSRQ) and 1 Narrow Line Seyfert 1 (NLSy1) galaxy. Our spectroscopic campaign will allow us to study the spectroscopic properties (FWHM, EW, flux) of broad-emission lines in the optical (e.g. H{\\beta}) and mid-UV (e.g. Mg II {\\lambda}2800) regimes, depending on the redshift of the source. The cadence of the broad emission lines monitoring is about five nights per month which in turn will permit us to explore whether there is a correlated variability between broad emission line features and high levels of {\\gamma}-ray emission.

  8. Spectrophotometric variability of the magnetic CP star alpha2 CVn

    CERN Document Server

    Sokolov, N A

    2011-01-01

    The spectrophotometric variability of the classical magnetic CP star alpha2 CVn in the ultraviolet spectral region from 1150 to 3200 A is investigated. This study is based on the archival International Ultraviolet Explorer data obtained at different phases of the rotational cycle. The brightness of the star at spectral region from 3015 to 3138 A is constant over the period of rotation which means that the so called 'null wavelength region' exist on these wavelengths. Moreover, the minima values of the amplitude of light curves are reached in the spectral region at \\lambda \\lambda 1660 and 1900 A. The monochromatic light curves in the 'pseudo-continuum' of this star change their shape with wavelength. All light curves with \\lambda 2505 A shows the phase displacement of the minimum from 0.0 at \\lambda 2505 A to 0.3 at \\lambda 2993 A.

  9. Spectrophotometric intracutaneous analysis for differential diagnosis of pigmented skin lesions

    Directory of Open Access Journals (Sweden)

    Е. V. Filonenko

    2013-01-01

    Full Text Available The non-invasive diagnosis of pigmented skin lesions by spectrophotometric intracutaneous analysis (SIA-scopy using device for dermatoscopy (SIAscope V by Astron Clinica, Ltd was approved in P.A.Herzen Moscow Cancer Research Institute. The method is based on analysis of light interaction with wavelength of 440–960 nm anf human skin, which is recorded by change of image on scan. The comparative analysis of SIA-scopy and histological data in 327 pigmented skin lesions in 147 patients showed, that SIA had high diagnostic efficiency for cutaneous melanoma: the sensitivity was 96%, specifity – 94%, diagnostic accuracy – 94%. For study of malignant potential of pigmented lesions by SIA-scopy the most informative capacity was obtained for assessment of melanin in papillary dermis, status of blood vessels and collagen fibres (SIA-scans 3, 4, 5.

  10. Simultaneous spectrophotometric estimation of nitazoxanide and ofloxacin in tablets

    Directory of Open Access Journals (Sweden)

    Madhuri D Game

    2011-01-01

    Full Text Available Two simple, accurate and precise spectrophotometric methods have been developed for simultaneous determination of nitazoxanide and ofloxacin in tablets. Method I is Q-absorbance ratio method which involves Q-absorbance at isobestic point (306.25 nm and max (347.5 nm of nitazoxanide, while method II is two wavelength method, where 244.6 nm and 273.0 nm were selected as 1 and 2 for determination of nitazoxanide and 294.3 nm and 388.1 nm were selected as 3 and 4 for determination of ofloxacin. Both drugs obeyed the Beer′s law in the concentration range 2-30 μg/ml,correlation coefficient (r 2 <1. Both methods were validated statistically and recovery studies were carried out to confirm the accuracy. Commercial tablet formulation was successfully analyzed using the developed methods.

  11. Kinetic spectrophotometric determination of bromide in clidinium-c drug

    Institute of Scientific and Technical Information of China (English)

    Ali Sheibani; M. Reza Shishehbore; Zahra Tavakolian Ardakani

    2011-01-01

    A simple, rapid and sensitive method has been described for the determination of the trace amounts of bromide. The method is based on the catalytic effect of bromide ion on the oxidation of methylene blue by bromate in sulfuric acid media. The reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of methylene blue at 665 nm. Bromide was determined in the range of 0.05-1.90 μg/mL with the detection limit of 0.03 μg/mL. The relative standard deviations of five replicate determinations of 0.20 and 10.0 μg/mL of bromide were 2.4% and 1.8%, respectively. The influence of potential interfering ions and substances was studied. The method is applied to the analysis of bromide in clidinium-c tablet as a real sample.

  12. Study of interplanetary hydrogen from Lyman alpha emission and absorption determination

    International Nuclear Information System (INIS)

    The purpose of the work submitted in this paper is to contribute to the study of interplanetary hydrogen from Lyman alpha emission and absorption measurements, carried out on board the D2A, OSO-8 and Copernicus satellites. This study, which was undertaken from the D2A satellite, moved us to study the interplanetary environment as from observations made from the following experiments placed on board the OSO-8 and Copernicus satellites. The experiment set up on board the OSO-8 satellite made it possible to obtain the profile of the solar alpha Lyman emission. An absorption profile was observed for the first time on these profiles and this made it possible to attribute them to interplanetary hydrogen and enabled us to make a direct and local determination of the solar ionization rate. - The spectrometer set up on board Copernicus made it possible to obtain the emission spectrum of the interplanetary environment at the same time as the geocorona. The overall velocity of the interplanetary environment was deduced from the Doppler shift between the two spectra. In the first part, the principle of the REA and POLAR experiments is recalled but only the REA experiment is described in detail, particularly the problems arising from the construction and calibration of the cell. In the second part, a study of the interplanetary environment made from the D2A determinations is presented in synthesized form. On the other hand, the study to which theses initial results led us is presented in detail. Finally, in the third part, the results obtained by means of the OSO-8 and Copernicus satellites are given

  13. Monte Carlo study of characteristics of uranium L-edge from X-ray absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seunghoon; Kwak, Sung-Woo; Shin, Jung-Ki; Kang, Han-Byeol; Chung, Heejun [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

    2015-05-15

    L-edge densitometry (LED) which is specially called X-ray Absorption Spectrometry (XAS) for uranium xray analysis is a technique of determination of uranium concentration as a continuous x-ray energy beams transmit a uranium liquid sample for safeguard. Compared to K-edge densitometer, since relatively lower energy of uranium L series energy than K series energy, L-edge densitometer does not require a liquid nitride cooling system. In this study, the simulation of uranium L-edge densitometer is performed using Monte Carlo method. Ledge spectrum, such as spectrum jumps, can be confirmed by the simulation. In further study, improvement of counting efficiency through collimation of x-ray, and shielding will be considered for detailed design of L-edge densitometer.

  14. USING FLY ASH TO STUDY ON THE MECHANISM OF THE ABSORPTION OF HEAVY METAL IONS IN WASTEWATER

    Institute of Scientific and Technical Information of China (English)

    程建光

    2000-01-01

    Using the method of sedentary thermal experiment, the use of fly ash to remove Zn2+,Cu2+ and Pb2+ in waste water was studied. Special attention was paid to the effects of pH and time degree of activity on absorbing ability. The freundlich model applicable to the absorption data was set. Also the mechanism of absorption and ultra-micro structure of fly ash with the help of TEM was put forward.

  15. Synthesis and Study of Two-photon Absorption Behavior of 3- (3-Arylacryloyl) -chromen-2-one Derivatives

    Institute of Scientific and Technical Information of China (English)

    SONG Hua-Can; LIANG Hui-Fen; SUN Yi-Feng; YAO Jun-Hua

    2003-01-01

    @@ The study on two-photon absorption materials has attracted a lot of attention in recent years, many good re search results have been obtained in the field of two-photon fluorescent microscopy and imaging. [ 1 ~ 4] It was found in our laboratory that some 3-(3-arylacryloyl)-chromen-2-one derivatives possess good two-photon absorption behav-ior, [5] therefore, a series of this family of compounds was synthesized.

  16. Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy

    Science.gov (United States)

    Harris, Don Ahmasi

    Ultrafast transient absorption spectroscopy was used to investigate the solvent dependent reaction dynamics of two prototypical chemical systems: (1) The ring-opening reaction of 1,3-cyclohexadiene, the isolated chromophore in Provitamin D, and (2) The photolysis of various Vitamin B12 cofactors. We investigated the influence of solvent polarity on the ground state conformational relaxation of 1,3,5-cis hexatriene subsequent to the ring opening of 1,3-cyclohexadiene in methanol and 1-propanol solvents. Comparisons to the conformational relaxation in alkane solvents studied earlier demonstrated a surprising influence of solvent polarity on single bond isomerization. Temperature dependent transient absorption measurements were performed on 1,3,5-cis hexatriene in cyclohexane and 1-propanol to determine the effect of solvent polarity on the activation energy barrier for ground state single bond isomerization. These measurements conclude that the polar solvent lowers the energy barrier for single bond isomerization allowing conformational relaxation to proceed faster in alcohol solvents compared to alkane solvents. With no perceived polar transition state for single bond isomerization, this result disagrees with the conventional view of solvation and differentiates the single bond isomerization dynamics of polyenes from alkanes. Transient absorption spectroscopy was also utilized to study the solvent effects in the photolysis of various B12 cofactors in different environments. We investigated the solvent dependent photolysis of adenosylcobalamin, methylcobalamin, and cyanocobalamin in water and ethylene glycol as a function of solvent temperature. In comparing the radical cage escape of adenosylcobalamin and cyanocobalamin, we determined a larger than expected hydrodynamic radii for the diffusing radicals in water compared to ethylene glycol, thus making necessary a revised perspective of solvent interaction with the diffusing radical. In addition, we investigated the

  17. Development Of New Visible Spectrophotometric Methods For Quantitative Determination Of Almotriptan Malate As An Active Pharmaceutical Ingredient In Formulations

    Directory of Open Access Journals (Sweden)

    U. Viplava Prasad

    2012-06-01

    Full Text Available Purpose: The aim of the investigation was to see the simple and sensitive visible spectrophotometric methods for the determination of the almotriptan malate in bulk and tablet dosage forms. Methods: Two simple, sensitive and cost effective visible spectrophotometric methods (M1-M2 were developed for the estimation of almotriptan malate in bulk and dosage forms. The first method (M1 is based on the formation of blue reduced product by treating drug with Folin Ciocalteu (FC reagent in the presence of sodium carbonate solution with an absorption maximum of 770nm. The second method (M2 is based on the complex formation product by drug with 1, 10-phenanthroline in the presence of Fe (III as an oxidant in phosphoric acid medium with an absorption maximum of 510nm. Results: Beer’s law obeyed in the concentration range of 4-12μg/ml and 1-5 μg/ml for methodM1 and M2 respectively. No interference was observed from the usually existing additives in pharmaceutical formulations and the applicability of the methods was examined by analyzing AXERT tablets containing AM. Conclusion: The reported methods for its assay involve sophisticated equipment, which are very costly and pose problems of maintenance. To overcome these problems, the use of visible spectrophotometric technique is justifiable. The statistical data proved the accuracy, reproducibility and the precision of the proposed methods.

  18. Study on the absorption site of divalent cations in the intestinal loop, using the multitracer technique

    International Nuclear Information System (INIS)

    The duodenum is thought to be the principal site for Ca absorption, which showed a significant increase in Ca absorption during pregnancy. The active transport of Mg in the colon may occur in a nonpregnant state, while no such evidence was observed during gestation. The present data suggest that each part of the intestinal loop is responsible for the absorption of a particular cation. (author)

  19. Measurements of the Absorption by Auditorium SEATING—A Model Study

    Science.gov (United States)

    BARRON, M.; COLEMAN, S.

    2001-01-01

    One of several problems with seat absorption is that only small numbers of seats can be tested in standard reverberation chambers. One method proposed for reverberation chamber measurements involves extrapolation when the absorption coefficient results are applied to actual auditoria. Model seat measurements in an effectively large model reverberation chamber have allowed the validity of this extrapolation to be checked. The alternative barrier method for reverberation chamber measurements was also tested and the two methods were compared. The effect on the absorption of row-row spacing as well as absorption by small numbers of seating rows was also investigated with model seats.

  20. Rotational molecular dynamics of laser-manipulated bromotrifluoromethane studied by x-ray absorption

    International Nuclear Information System (INIS)

    We present a computational study of the rotational molecular dynamics of bromotrifluoromethane (CF3Br) molecules in gas phase. The rotation is manipulated with an off-resonant 800 nm laser. The molecules are treated as rigid rotors. Frequently, we use a computationally efficient linear rotor model for CF3Br, which we compare with selected results for full symmetric-rotor computations. The expectation value 2 θ>(t) is discussed. Especially, the transition from impulsive to adiabatic alignment, the temperature dependence of the maximally achievable alignment, and its intensity dependence are investigated. In a next step, we examine resonant x-ray absorption as an accurate tool to study laser manipulation of molecular rotation. Specifically, we investigate the impact of the x-ray pulse duration on the signal (particularly its temporal resolution) and study the temperature dependence of the achievable absorption. Most importantly, we demonstrated that using picosecond x-ray pulses, one can accurately measure the expectation value 2 θ>(t) for impulsively aligned CF3Br molecules. We point out that a control of the rotational dynamics opens up a novel way to imprint shapes onto long x-ray pulses on a picosecond time scale. For our computations, we determine the dynamic polarizability tensor of CF3Br using ab initio molecular linear-response theory in conjunction with wave function models of increasing sophistication: Coupled-cluster singles (CCS), second-order approximate coupled-cluster singles and doubles (CC2), and coupled-cluster singles and doubles (CCSD).

  1. Application of X-ray Absorption Spectroscopy to the study of nuclear structural materials

    Science.gov (United States)

    Liu, Shanshan

    One of key technologies for the next generation nuclear systems are advanced materials, including high temperature structural materials, fast neutron resistance core materials and so on. Local structure determination in these systems, which often are crystallographically intractable, is critical to gaining an understanding of their properties. In this thesis, X-ray Absorption Spectroscopy (XAS), including Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES), is used to examine the geometric and electronic structure of nuclear structural materials under varying conditions. The thesis is divided into two main sections. The first examines the structural analysis of nanostructured ferritic alloys (NFA) which are dispersion strengthened by an ultra high density of Y-Ti-O enriched nano-features, resulting in remarkable high temperature creep strength and radiation damage resistance. Titanium and Yttrium K-edge XAS shows commercial alloys MA957 and J12YWT more closely resemble the as received Fe-14Cr-3W-0.4Ti (wt. %) powders, and mechanically alloyed (MA) powders with 0.25Y2O3 (wt. %). It shows that a significant fraction of substitutional Ti remains dissolved in the (BCC) ferrite matrix. In contrast, annealed powders and hot isostatic press (HIP) consolidated alloys show high temperature heat treatments shift the Y and Ti to more oxidized states that are consistent with combinations of Y2Ti2O7 and, especially, TiO. The second section describes corrosion studies of Pb with 316L stainless steel, molybdenum and spinet (MgAl2O4) at high temperature by XAS. The corrosion of fuel cladding and structural materials by liquid lead at elevated temperatures is an issue that must be considered when designing advanced nuclear systems and high-power spallation neutron targets. The results of ex-situ studies show that a Mo substrate retained a smooth and less corroded surface than 316L stainless steel sample at elevated temperature. In

  2. Microbeam x-ray absorption spectroscopy study of chromium in large-grain uranium dioxide fuel

    Science.gov (United States)

    Mieszczynski, C.; Kuri, G.; Bertsch, J.; Martin, M.; Borca, C. N.; Delafoy, Ch; Simoni, E.

    2014-09-01

    Synchrotron-based microprobe x-ray absorption spectroscopy (XAS) has been used to study the local atomic structure of chromium in chromia-doped uranium dioxide (UO2) grains. The specimens investigated were a commercial grade chromia-doped UO2 fresh fuel pellet, and materials from a spent fuel pellet of the same batch, irradiated with an average burnup of ~40 MW d kg-1. Uranium L3-edge and chromium K-edge XAS have been measured, and the structural environments of central uranium and chromium atoms have been elucidated. The Fourier transform of uranium L3-edge extended x-ray absorption fine structure shows two well-defined peaks of U-O and U-U bonds at average distances of 2.36 and 3.83 Å. Their coordination numbers are determined as 8 and 11, respectively. The chromium Fourier transform extended x-ray absorption fine structure of the pristine UO2 matrix shows similar structural features with the corresponding spectrum of the irradiated spent fuel, indicative of analogous chromium environments in the two samples studied. From the chromium XAS experimental data, detectable next neighbor atoms are oxygen and uranium of the cation-substituted UO2 lattice, and two distinct subshells of chromium and oxygen neighbors, possibly because of undissolved chromia particles present in the doped fuels. Curve-fitting analyses using theoretical amplitude and phase-shift functions of the closest Cr-O shell and calculations with ab initio computer code FEFF and atomic clusters generated from the chromium-dissolved UO2 structure have been carried out. There is a prominent reduction in the length of the adjacent Cr-O bond of about 0.3 Å in chromia-doped UO2 compared with the ideal U-O bond length in standard UO2 that would be expected because of the change in effective Coulomb interactions resulting from replacing U4+ with Cr3+ and their ionic size differences. The contraction of shortest Cr-U bond is ~0.1 Å relative to the U-U bond length in bulk UO2. The difference in the

  3. Spectroscopic studies of micelle-enhanced ligand exchange of gallium (III)/4-(2-pyridylazo) resorcinol complex by calf thymus DNA

    Science.gov (United States)

    Romeika, Jennifer M.; Spurgeon, Charina L.; Yan, Fei

    2014-01-01

    The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of gallium (III) with 4-(2-pyridylazo) resorcinol (PAR) under varying conditions has been studied spectrophotometrically. At pH 6.0, CTAB (0.05% w/v) markedly enhanced the absorption intensity of gallium (III)-PAR complex. Furthermore, the introduction of CTAB provided unique selectivity for the ligand exchange of Ga(III)-PAR by calf thymus dsDNA over calf thymus ssDNA. This phenomenon offers a novel spectrophotometric sensing strategy for direct detection of dsDNA.

  4. Electronic topological transition in zinc under pressure: An x-ray absorption spectroscopy study

    Science.gov (United States)

    Aquilanti, G.; Trapananti, A.; Minicucci, M.; Liscio, F.; Twaróg, A.; Principi, E.; Pascarelli, S.

    2007-10-01

    Zinc metal has been studied at high pressure using x-ray absorption spectroscopy. In order to investigate the role of the different degrees of hydrostaticity on the occurrence of structural anomalies following the electronic topological transition, two pressure transmitting media have been used. Results show that the electronic topological transition, if it exists, does not induce an anomaly in the local environment of compressed Zn as a function of hydrostatic pressure and any anomaly must be related to a loss of hydrostaticity of the pressure transmitting medium. The near-edge structures of the spectra, sensitive to variations in the electronic density of states above the Fermi level, do not show any evidence of electronic transition whatever pressure transmitting medium is used.

  5. X-ray absorption studies of gamma irradiated Nd doped phosphate glass

    International Nuclear Information System (INIS)

    This paper presents the X-ray absorption near edge structure (XANES) studies of Nd doped phosphate glasses before and after gamma irradiation. The intensity and location of LIII edge white line peak of Nd changes depending on its concentration as well as on the ratio of O/Nd in the glass matrix. The decrease in the peak intensity of white line after gamma irradiation indicates towards reduction of Nd3+ to Nd2+ in the glass matrix, which increases with an increase in the doses of gamma irradiation. Similarity in the XANES spectra of Nd doped phosphate glasses and Nd2O3 suggests that coordination geometry around Nd3+ in glass samples may be identical to that of Nd2O3

  6. X-ray absorption studies of gamma irradiated Nd doped phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Rai, V. N., E-mail: vnrai@rrcat.gov.in [Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India); Rajput, Parasmani; Jha, S. N.; Bhattacharyya, D. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2015-06-24

    This paper presents the X-ray absorption near edge structure (XANES) studies of Nd doped phosphate glasses before and after gamma irradiation. The intensity and location of L{sub III} edge white line peak of Nd changes depending on its concentration as well as on the ratio of O/Nd in the glass matrix. The decrease in the peak intensity of white line after gamma irradiation indicates towards reduction of Nd{sup 3+} to Nd{sup 2+} in the glass matrix, which increases with an increase in the doses of gamma irradiation. Similarity in the XANES spectra of Nd doped phosphate glasses and Nd{sub 2}O{sub 3} suggests that coordination geometry around Nd{sup 3+} in glass samples may be identical to that of Nd{sub 2}O{sub 3}.

  7. Hydrogen absorption study of Ti-based alloys performed by melt-spinning

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, R.M.; Lemus, L.F.; Santos, D.S. dos, E-mail: rafaella@metalmat.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEMM/COPPEP/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2013-11-01

    The hydrogen absorption and desorption of Ti{sub 53}Zr{sub 27}Ni{sub 20} icosahedral quasicrystal (ICQ) and Ti{sub 50}Ni{sub 50} shape memory alloy (SMA) melt-spun ribbons was studied. Samples were exposed to hydrogen gas at 623 K and 4 MPa for 1000 minutes. The total capacity of hydrogen obtained for Ti{sub 53}Zr{sub 27}Ni{sub 20} and Ti{sub 50}Ni{sub 50} was 3.2 and 2.4 wt. % respectively. The Thermal Desorption Spectrometry (TDS) of the hydrogenated alloys shows that both alloys start to desorb hydrogen around 750 K. X-ray diffraction (XRD) patterns, performed after hydrogenation, indicate a complete amorphization of the Ti{sub 53}Zr{sub 27}Ni{sub 20} i-phase alloy, while the Ti{sub 50}Ni{sub 50} alloy remained crystalline after hydride formation. (author)

  8. A microwave absorption study in the thermochromic SrMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G. [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510 Coyoacan, DF (Mexico)], E-mail: memodin@yahoo.com; Heiras, J. [Centro de Ciencias de la Materia Condensada, Universidad Nacional Autonoma de Mexico, Apartado Postal 356, 22800 Ensenada, BC (Mexico); Castellanos, M. [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, 04510 Mexico DF (Mexico); Valenzuela, R. [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510 Coyoacan, DF (Mexico)

    2008-07-15

    We report electron paramagnetic resonance (EPR) and magnetically modulated microwave absorption spectroscopy (MAMMAS) studies at X-band (8.8-9.6 GHz) on powdered SrMnO{sub 3} in the 90-400 K temperature range. EPR spectrum shows one broad single-line at room temperature, which is observed only above 280.5 K, being compatible with an antiferromagnetic order. The onset of the para-antiferromagnetic transition has been determined from the temperature dependence of three main parameters extracted from the EPR spectra: resonant field (H{sub res}), peak-to-peak linewidth ({delta}H{sub pp}) and integrated intensity (I{sub EPR}). The MAMMAS response shows a change in the region 276-283 K, compatible with the para-antiferromagnetic transition, without presenting any significant change in the region of thermochromism.

  9. Optical absorption and photoluminescence studies of gold nanoparticles deposited on porous silicon

    Science.gov (United States)

    Amran, Tengku Sarah Tengku; Hashim, Md Roslan; Al-Obaidi, Nihad K. Ali; Yazid, Hanani; Adnan, Rohana

    2013-01-01

    We present an investigation on a coupled system consists of gold nanoparticles and silicon nanocrystals. Gold nanoparticles (AuNPs) embedded into porous silicon (PSi) were prepared using the electrochemical deposition method. Scanning electron microscope images and energy-dispersive X-ray results indicated that the growth of AuNPs on PSi varies with current density. X-ray diffraction analysis showed the presence of cubic gold phases with crystallite sizes around 40 to 58 nm. Size dependence on the plasmon absorption was studied from nanoparticles with various sizes. Comparison with the reference sample, PSi without AuNP deposition, showed a significant blueshift with decreasing AuNP size which was explained in terms of optical coupling between PSi and AuNPs within the pores featuring localized plasmon resonances.

  10. Magnetization and Specific Absorption Rate Studies of Ball-Milled Iron Oxide Nanoparticles for Biomedicine

    Directory of Open Access Journals (Sweden)

    P. Burnham

    2013-01-01

    Full Text Available Comparative studies are presented of iron oxide nanoparticles in the 7–15 nm average diameter range ball milled in hexane in the presence of oleic acid. Transmission electron microscopy identified spherical particles of decreasing size as milling time and/or surfactant concentration increased. Micromagnetic characterization via Mössbauer spectroscopy at room temperature yielded broadened magnetic spectroscopic signatures, while macromagnetic characterization via vibrating sample magnetometry of 7-8 nm diameter particles showed largely superparamagnetic behavior at room temperature and hysteretic at 2 K. Zero-field and field-cooled magnetization curves exhibited a broad maximum at ~215 K indicating the presence of strong interparticle magnetic interactions. The specific absorption rates of ferrofluids based on these nanoparticle preparations were measured in order to test their efficacies as hyperthermia agents.

  11. Study on the surface hydroxyl group on solid breeding materials by infrared absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    Hydroxyl groups on the surface of Li{sub 2}O were studied by using a diffuse reflectance method with Fourier transform infrared absorption spectroscopy at high temperature up to 973K under controlled D{sub 2}O or D{sub 2} partial pressure. It was found that hydroxyl groups could exist on Li{sub 2}O surface up to 973K under Ar atmosphere. Under D{sub 2}O containing atmosphere, only the sharp peak at 2520cm{sup -1} was observed at 973K in the O-D stretching vibration region. Below 973K, multiple peaks due to the surface -OD were observed and they showed different behavior with temperature or atmosphere. Multiple peaks mean that surface is not homogeneous for D{sub 2}O adsorption. Assignment of the observed peaks to the surface bonding structure was also discussed. (author)

  12. The spectrophotometric determination of boron in tourmalines

    Directory of Open Access Journals (Sweden)

    LJILJANA JAKSIC

    2005-02-01

    Full Text Available A procedure for the spectrophotometric determination of macro amounts of boron in tourmaline with azomethine H is described. The used tourmaline concentrate was obtained by magnetic separation and heavy-liquids purification of the schorl zone of pegmatite or granite aplite. The samples of tourmaline were decomposed by fusion with anhydrous sodium carbonate and taken up in dilute hydrochloric acid. The interfering effects of iron and aluminium were eliminated by masking with an EDTA – NTA solution. After pH adjustment, the boron was reacted with azomethine H and the absorbance of the obtained coloured complex was measured at 415 nm. The results are compared with those obtained by other procedures. The relative error of the determination was less than 3 %.

  13. Spectrophotometric determination of azathioprine in pharmaceutical formulations.

    Science.gov (United States)

    Lakshmi, C S; Reddy, M N

    1998-12-01

    Four simple and sensitive visible spectrophotometric methods (A-D) have been described for the assay of azathioprine (ATP) either in pure form or in pharmaceutical formulations. Methods A and B are based on the oxidation of ATP with excess N-bromosuccinimide (NBS) or chloramine-T (CAT) and determining the consumed NBS or CAT with a decrease in colour intensity of celestine blue (CB) (method A) or gallocyanine (GC) (method B), respectively. Methods C and D are based on the diazotisation of reduced azathioprine (RATP) with excess nitrous acid and estimating either the consumed nitrous acid (HNO(2)) with cresyl fast violet acetate (CFVA) (method C) or by coupling reaction of the diazonium salt formed with N-1-naphthyl ethylene diamine dihydrochloride (NED) (method D). All of the variables have been optimized and the reactions presented. The concentration measurements are reproducible within a relative standard deviation of 1.0%. Recoveries are 99.2-100.3%. PMID:18967434

  14. Spectrophotometric estimation of azithromycin in tablets

    Directory of Open Access Journals (Sweden)

    B K Jayanna

    2012-01-01

    Full Text Available The present manuscript describes a simple, sensitive, accurate, precise and economical visible spectrophotometric method for the estimation of azithromycin from tablet formulation. The method is based on the reduction of potassium permanganate in alkaline medium with azithromycin. The measurement of decrease in absorbance of potassium permanganate at 547 nm was done, as it decolourises upon reduction by azithromycin. The method was used to determine between 2 and 20 μg/ml of azithromycin in the final measured solution. There is no interference from the ingredients commonly found in azithromycin tablets with this method. The results for the determination of azithromycin in tablets were in good agreement with the labelled quantities and related analytical parameters are calculated.

  15. Spectrophotometric estimation of azithromycin in tablets.

    Science.gov (United States)

    Jayanna, B K; Nagendrappa, G; Arunkumar; Gowda, N

    2012-07-01

    The present manuscript describes a simple, sensitive, accurate, precise and economical visible spectrophotometric method for the estimation of azithromycin from tablet formulation. The method is based on the reduction of potassium permanganate in alkaline medium with azithromycin. The measurement of decrease in absorbance of potassium permanganate at 547 nm was done, as it decolourises upon reduction by azithromycin. The method was used to determine between 2 and 20 μg/ml of azithromycin in the final measured solution. There is no interference from the ingredients commonly found in azithromycin tablets with this method. The results for the determination of azithromycin in tablets were in good agreement with the labelled quantities and related analytical parameters are calculated. PMID:23626394

  16. An Atlas of Spectrophotometric Landolt Standard Stars

    CERN Document Server

    Stritzinger, M; Hamuy, M; Challis, P M; Demarco, R; Germany, L; Soderberg, A M; Stritzinger, Maximilian; Suntzeff, Nicholas B.; Hamuy, Mario; Challis, Peter; Demarco, Ricardo; Germany, Lisa

    2005-01-01

    We present CCD observations of 102 Landolt standard stars obtained with the R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models we have extended the flux points to our six spectrophotometric secondary standards, in both the blue and the red, allowing us to produce flux-calibrated spectra that span a wavelength range from 3050 \\AA to 1.1 \\micron. We find mean differences between $UBVRI$ spectrophotometry computed using Bessell's standard passbands and Landolt's published photometry to be 1% or less. Observers in both hemispheres will find these spectra useful for flux-calibrating spectra and through the use of accurately constructed instrumental passbands be able to compute accurate corrections to bring instrumental magnitudes to any desired standard photometric system (S-corrections). In addition, by combining empirical and modeled spectra of the Sun, Sirius and Vega, we calculate and compare synthetic photometry to observed photometry taken from the literature for these three stars.

  17. Spectrophotometric discrimination of river dissolved organic matter

    Science.gov (United States)

    Baker, Andy

    2002-11-01

    There is a need to be able to differentiate the dissolved organic matter (DOM) fraction in river waters. Research in the 1970s and 1980s has attempted to utilize both absorbance and fluorescence to distinguish between DOM fractions in river waters, but both were limited by the available technology. Total organic carbon content has, therefore, been widely used as a standard method of measuring DOM concentration, although it has little power to differentiate DOM fractions. Recent advances in fluorescence spectrophotometry enable rapid and optically precise analysis of DOM. Here, we show how a combination of both fluorescence and absorbance can be used to discriminate statistically between spatial variations of DOM in tributaries in a small catchment of the Ouseburn, NE England. The results of the discriminant analysis suggest that about 70% of the samples can be correctly classified to its tributary. Discriminant function 1 explains 60·8% of the variance in the data and the fulvic-like fluorescence intensity has the largest absolute correlation within this function; discriminant function 2 explains a further 21·5% of the variance and the fulvic-like fluorescence emission wavelength has the largest absolute correlation within this function. The discriminant analysis does not correctly classify all tributaries every time, and successfully discriminates between the different tributaries 70% of the time. Occasions when the tributary waters are less well discriminated are due to either episodic pollution events (at two sites) or due to tributaries that have strong seasonal trends in spectrophotometric parameters, which allows the sites to be misclassified. Results suggest that spectrophotometric techniques have considerable potential in the discrimination of DOM in rivers.

  18. Spectrophotometric Analysis of Phosphoric Acid Leakage in High-Temperature Phosphoric Acid-Doped Polybenzimidazole Membrane Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Seungyoon Han

    2016-01-01

    Full Text Available High-temperature proton exchange membrane fuel cells (HT-PEMFCs utilize a phosphoric acid- (PA- doped polybenzimidazole (PBI membrane as a polymer electrolyte. The PA concentration in the membrane can affect fuel cell performance, as a significant amount of PA can leak from the membrane electrode assembly (MEA by dissolution in discharged water, which is a byproduct of cell operation. Spectrophotometric analysis of PA leakage in PA-doped polybenzimidazole membrane fuel cells is described here. This spectrophotometric analysis is based on measurement of absorption of an ion pair formed by phosphomolybdic anions and the cationoid color reagent. Different color reagents were tested based on PA detection sensitivity, stability of the formed color, and accuracy with respect to the amount of PA measured. This method allows for nondestructive analysis and monitoring of PA leakage during HT-PEMFCs operation.

  19. Validated spectrophotometric methods for the estimation of moxifloxacin in bulk and pharmaceutical formulations

    Science.gov (United States)

    Motwani, Sanjay K.; Chopra, Shruti; Ahmad, Farhan J.; Khar, Roop K.

    2007-10-01

    New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods were developed and validated for the estimation of moxifloxacin in bulk and pharmaceutical formulations. Moxifloxacin was estimated at 296 nm in 0.1N hydrochloric acid (pH 1.2) and at 289 nm in phosphate buffer (pH 7.4). Beer's law was obeyed in the concentration range of 1-12 μg ml -1 ( r2 = 0.9999) in hydrochloric acid and 1-14 μg ml -1 ( r2 = 0.9998) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.63 × 10 4 l mol -1 cm -1 and 9.5 ng cm -2/0.001 A in hydrochloric acid; and 4.08 × 10 4 l mol -1 cm -1 and 10.8 ng cm -2/0.001 A in phosphate buffer media, respectively indicating the high sensitivity of the proposed methods. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.0402, 0.1217 μg ml -1 in hydrochloric acid and 0.0384, 0.1163 μg ml -1 in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of moxifloxacin in pharmaceutical formulations (tablets, i.v. infusions, eye drops and polymeric nanoparticles). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation moxifloxacin in different dosage forms and dissolution studies.

  20. Study on Nonlinear Absorption Effect of Nanosecond Pulse Laser Irradiation for GaAs.

    Science.gov (United States)

    Sun, Wenjun; Liu, Zhongyang; Zhou, Haijiao

    2016-04-01

    In order to research nonlinear absorption effect of pulse laser irradiation for GaAs, a physical model of Gaussian distribution pulse laser irradiation for semiconductor material was established by software COMSOL Multiphysics. The thermal effects of semiconductor material GaAs was analyzed under irradiation of nanosecond pulse laser with wavelength of 1064 nm. The radial and transverse temperature distribution of semiconductor material GaAs was calculated under irradiation of nanosecond pulse laser with different power density by solving the thermal conduction equations. The contribution of one-photon absorption, two-photon absorption and free carrier absorption to temperature of GaAs material were discussed. The results show that when the pulse laser power density rises to 10(10) W/cm2, free carrier absorption played a leading role and it was more than that of one-photon absorption of material. The temperature contribution of two-photon absorption and free carrier absorption could be ignored at laser power density lower than 10(8) W/cm2. The result is basically consistent with relevant experiments, which shows that physical model constructed is valid. PMID:27451733

  1. Vitamin D-mediated calcium absorption in patients with clinically stable Crohn's disease: a pilot study

    Science.gov (United States)

    Vitamin D is the critical hormone for intestinal absorption of calcium. Optimal calcium absorption is important for proper mineralization of bone in the prevention of osteoporosis and osteoporotic fractures, among other important functions. Diseases associated with gut inflammation, such as Crohn's ...

  2. Online spectrophotometric determination of Fe(II) and Fe(III) by flow injection combined with low pressure ion chromatography

    Science.gov (United States)

    Chen, Shujuan; Li, Nan; Zhang, Xinshen; Yang, Dongjing; Jiang, Heimei

    2015-03-01

    A simple and new low pressure ion chromatography combined with flow injection spectrophotometric procedure for determining Fe(II) and Fe(III) was established. It is based on the selective adsorption of low pressure ion chromatography column to Fe(II) and Fe(III), the online reduction reaction of Fe(III) and the reaction of Fe(II) in sodium acetate with phenanthroline, resulting in an intense orange complex with a suitable absorption at 515 nm. Various chemical (such as the concentration of colour reagent, eluant and reductive agent) and instrumental parameters (reaction coil length, reductive coil length and wavelength) were studied and were optimized. Under the optimum conditions calibration graph of Fe(II)/Fe(III) was linear in the Fe(II)/Fe(III) range of 0.040-1.0 mg/L. The detection limit of Fe(III) and Fe(II) was respectively 3.09 and 1.55 μg/L, the relative standard deviation (n = 10) of Fe(II) and Fe(III) 1.89% and 1.90% for 0.5 mg/L of Fe(II) and Fe(III) respectively. About 2.5 samples in 1 h can be analyzed. The interfering effects of various chemical species were studied. The method was successfully applied in the determination of water samples.

  3. Study on the improved structure of dye-sensitized solar cells for enhancing light absorption

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; SHEN Hui; DENG Youjun

    2007-01-01

    The absorption coefncients of N719 or N3 dyes at the longer wavelength region (>600 nm)are not enough to catch photons efficiently,but the solar spectrum has a large photon flux in the wavelength region between 500 and 1,000 nm,so it is desirable to enhance the absorption of light by the dye-sensitized solar cells(DSSC)to achieve higher efficiencies.To solve this problem,an improved structure Of DSSC for enhancing light absorption is introduced in this paper, and I-V characteristics of DSSC are measured to illustrate the enhancement of the light absorption and efficiency.As a result,the improved DSSC exhibits higher light absorption and solar-to-electric conversion efficiency than traditional DSSC.

  4. Tunable Microwave Absorption Frequency by Aspect Ratio of Hollow Polydopamine@α-MnO2 Microspindles Studied by Electron Holography.

    Science.gov (United States)

    She, Wen; Bi, Han; Wen, Zhiwei; Liu, Qinghe; Zhao, Xuebing; Zhang, Jie; Che, Renchao

    2016-04-20

    A tunable response frequency is highly desirable for practical applications of microwave absorption materials but remains a great challenge. Here, hollow lightweight polydopamine@α-MnO2 microspindles were facilely synthesized with the tunable absorption frequency governed by the aspect ratio. The size of the hard template is a key factor to achieve the unique shape; the polymer layer with uniform thickness plays an important role in obtaining spindles with homogeneous size. With the aspect ratio increasing, the maximum reflection loss, as well as the absorption bandwidth (<-10 dB), increases and then decreases; meanwhile, the microwave absorption band shifts to the low frequency. The optimized aspect ratio of the cavity about the hollow polydopamine@α-MnO2 microspindles is ∼2.8. With 3 mm thickness at 9.7 GHz, the strongest reflection reaches -21.8 dB, and the width of the absorbing band (<-10 dB) is as wide as 3.3 GHz. Via electron holography, it is confirmed that strong charge accumulates around the interface between the polydopamine and α-MnO2 layers, which mainly contributes to the dielectric polarization absorption. This study proposes a reliable strategy to tune the absorption frequency via different aspect ratio polymer@α-MnO2 microspindles. PMID:27027922

  5. Theoretical modeling of the spectroscopic absorption properties of luciferin and oxyluciferin: A critical comparison with recent experimental studies

    Energy Technology Data Exchange (ETDEWEB)

    Anselmi, Massimiliano, E-mail: m.anselmi@caspur.it [Department of Chemistry, University of Rome ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Marocchi, Simone [Department of Chemistry, University of Rome ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Aschi, Massimiliano [Department of Chemistry, Chemical Engineering and Materials, University of L' Aquila, Via Vetoio (Coppito 1), 67100 Coppito, L' Aquila (Italy); Amadei, Andrea [Department of Chemistry, University of Rome ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2012-01-02

    Highlights: Black-Right-Pointing-Pointer The calculated absorption spectra were compared with experimental data. Black-Right-Pointing-Pointer Shapes and absorption maxima were reproduced for luciferin and oxyluciferin spectra. Black-Right-Pointing-Pointer The effect of the solvent largely changes the electronic transition probabilities. Black-Right-Pointing-Pointer Higher excitations provide an important contribution to the main absorption peak. - Abstract: Firefly luciferin and its oxidated form, oxyluciferin, are two heterocyclic compounds involved in the enzymatic reaction, catalyzed by redox proteins called luciferases, which provides the bioluminescence in a wide group of arthropods. Whereas the electronic absorption spectra of D-luciferin in water at different pHs are known since 1960s, only recently reliable experimental electronic spectra of oxyluciferin have become available. In addition oxyluciferin is involved in a triple chemical equilibria (deprotonation of the two hydroxyl groups and keto-enol tautomerism of the 4-hydroxythiazole ring), that obligates to select during an experiment a predominant species, tuning pH or solvent polarity besides introducing chemical modifications. In this study we report the absorption spectra of luciferin and oxyluciferin in each principal chemical form, calculated by means of perturbed matrix method (PMM), which allowed us to successfully introduce the effect of the solvent on the spectroscopic absorption properties, and compare the result with available experimental data.

  6. Theoretical modeling of the spectroscopic absorption properties of luciferin and oxyluciferin: A critical comparison with recent experimental studies

    International Nuclear Information System (INIS)

    Highlights: ► The calculated absorption spectra were compared with experimental data. ► Shapes and absorption maxima were reproduced for luciferin and oxyluciferin spectra. ► The effect of the solvent largely changes the electronic transition probabilities. ► Higher excitations provide an important contribution to the main absorption peak. - Abstract: Firefly luciferin and its oxidated form, oxyluciferin, are two heterocyclic compounds involved in the enzymatic reaction, catalyzed by redox proteins called luciferases, which provides the bioluminescence in a wide group of arthropods. Whereas the electronic absorption spectra of D-luciferin in water at different pHs are known since 1960s, only recently reliable experimental electronic spectra of oxyluciferin have become available. In addition oxyluciferin is involved in a triple chemical equilibria (deprotonation of the two hydroxyl groups and keto-enol tautomerism of the 4-hydroxythiazole ring), that obligates to select during an experiment a predominant species, tuning pH or solvent polarity besides introducing chemical modifications. In this study we report the absorption spectra of luciferin and oxyluciferin in each principal chemical form, calculated by means of perturbed matrix method (PMM), which allowed us to successfully introduce the effect of the solvent on the spectroscopic absorption properties, and compare the result with available experimental data.

  7. Adsorption of mercury on lignin: Combined surface complexation modeling and X-ray absorption spectroscopy studies

    International Nuclear Information System (INIS)

    Adsorption of mercury (Hg) on lignin was studied at a range of pH values using a combination of batch adsorption experiments, a surface complexation model (SCM) and synchrotron X-ray absorption spectroscopy (XAS). Surface complexation modeling indicates that three types of acid sites on lignin surfaces, namely aliphatic carboxylic-, aromatic carboxylic- and phenolic-type surface groups, contributed to Hg(II) adsorption. The bond distance and coordination number of Hg(II) adsorption samples at pH 3.0, 4.0 and 5.5 were obtained from extended X-ray absorption fine structure (EXAFS) spectroscopy analysis. The results of SCM and XAS combined reveal that the predominant adsorption species of Hg(II) on lignin changes from HgCl20 to monodentate complex –C–O–HgCl and then bidentate complex –C–O–Hg–O–C– with increasing pH value from 2.0 to 6.0. The good agreement between SCM and XAS results provides new insight into understanding the mechanisms of Hg(II) adsorption on lignin. - Highlights: ► Lignin exhibits a high Hg(II) adsorption capability. ► Adsorption of Hg(II) on lignin is strongly pH-dependent. ► HgCl20, –C–O–HgCl and –C–O–Hg–O–C– are the main adsorption species of Hg(II). - Adsorption of Hg(II) on lignin is strongly pH-dependent, and the main adsorption Hg(II) species change from HgCl20 to –C–O–HgCl and –C–O–Hg–O–C– as pH increases from 2.0 to 6.0.

  8. [Study on determination of plume velocity by passive differential optical absorption spectroscopy].

    Science.gov (United States)

    Li, Ang; Xie, Pin-hua; Liu, Wen-qing; Liu, Jian-guo; Dou, Ke; Lin, Yi-hui

    2008-10-01

    Differential optical absorption spectroscopy (DOAS) technique has been used to measure various trace gases in the atmosphere by their strongly structured absorption of radiation in the UV and visible spectral range. Passive DOAS using the zenith scattered sunlight as the light source can obtain the continuous column density distribution of air pollutants (such as SO2 and NO2) by scanning the plume emitted from sources on a mobile platform, then with the plume velocity information the total emission value can be ultimately estimated. In practice it is hard to calculate the total emission because there is no efficient way to accurately get the plume velocity which is the most important parameter. Usually the wind speed near ground is used as the actual plume speed, which constitutes the greatest source of uncertainty in the passive DOAS measurements for the total emission calculation. A passive DOAS method for the determination of plume velocity of pollution source was studied in the present paper. Two passive DOAS systems were placed under the plume along the plume transmission direction to observed the scattered sunlight at one fixed sepasation angle, and then the plume velocity was derived from the time delay resulting from the plume moving a certain distance, and also the plume height needed in the plume velocity calculation was measured by the same two passive DOAS systems. Measurement of the plume emitted from a certain power plant was carried out by the two passive DOAS systems and the plume velocities of 3.6 and 5.4 m x s(-1) at two separate moments were derived. The comparison with the wind speed measured at the same time by the single theodolite wind observation method indicates that this optical remote sensing method based on passive DOAS can be used to determine the plume velocity by monitoring the total emission from sources. PMID:19123375

  9. Determination of the acidity constants of neutral red and bromocresol green by solution scanometric method and comparison with spectrophotometric results

    Directory of Open Access Journals (Sweden)

    Ardeshir Shokrollahi

    2016-03-01

    The method is based on scanning cells containing the indicator solution with a scanner, and analyzing the color of each cell with a software written in visual basic (VB 6 media to red, green and blue values. The cells were made by making holes in the Plexiglas® sheet. Also, the acidity constants of the neutral red and bromocresol green indicators were studied with spectrophotometrically. HypSpec program has been applied for the estimation of pKa values based on spectrophotometric data. The agreement between obtained pKa values by solution scanometric, spectrophotometric method and values reported in the literature demonstrates the utility of the method here used. Also the HySS 2009 program was applied for drawing of the corresponding distribution diagrams.

  10. Validation of spectrophotometric method for lactulose assay in syrup preparation

    Science.gov (United States)

    Mahardhika, Andhika Bintang; Novelynda, Yoshella; Damayanti, Sophi

    2015-09-01

    Lactulose is a synthetic disaccharide widely used in food and pharmaceutical fields. In the pharmaceutical field, lactulose is used as osmotic laxative in a syrup dosage form. This research was aimed to validate the spectrophotometric method to determine the levels of lactulose in syrup preparation and the commercial sample. Lactulose is hydrolyzed by hydrochloric acid to form fructose and galactose. The fructose was reacted with resorcinol reagent, forming compounds that give absorption peak at 485 nm. Analytical methods was validated, hereafter lactulose content in syrup preparation were determined. The calibration curve was linear in the range of 30-100 μg/mL with a correlation coefficient (r) of 0.9996, coefficient of variance (Vxo) of 1.1 %, limit of detection of 2.32 μg/mL, and limit of quantitation of 7.04 μg/mL. The result of accuracy test for the lactulose assay in the syrup preparation showed recoveries of 96.6 to 100.8 %. Repeatability test of lactulose assay in standard solution of lactulose and sample preparation syrup showed the coefficient of variation (CV) of 0.75 % and 0.7 %. Intermediate precision (interday) test resulted in coefficient of variation 1.06 % on the first day, the second day by 0.99 %, and 0.95 % for the third day. This research gave a valid analysis method and levels of lactulose in syrup preparations of samples A, B, C were 101.6, 100.5, and 100.6 %, respectively.

  11. The studies of high-frequency magnetic properties and absorption characteristics for amorphous-filler composites

    Science.gov (United States)

    Li, Z. W.; Yang, Z. H.

    2015-10-01

    Pure amorphous flake fillers and amorphous flakes coated by ferrite nanoparticles with core-shell-like structure were fabricated using mechanical ball-milling. The later with core-shell-like structure can greatly decrease permittivity and improve the absorption properties, as compared to the former. The absorption of all amorphous-filler composites has its origin in a quarter-wavelength resonator. Based on the resonator model, absorption frequency fA and the corresponding return loss RL are calculated, which are well consistent with observed values. It is also found that the resonance frequency is proportional to effective resistivity, based on William-Shockley-Kittel's eddy model.

  12. Toward picosecond time-resolved X-ray absorption studies of interfacial photochemistry

    Science.gov (United States)

    Gessner, Oliver; Mahl, Johannes; Neppl, Stefan

    2016-05-01

    We report on the progress toward developing a novel picosecond time-resolved transient X-ray absorption spectroscopy (TRXAS) capability for time-domain studies of interfacial photochemistry. The technique is based on the combination of a high repetition rate picosecond laser system with a time-resolved X-ray fluorescent yield setup that may be used for the study of radiation sensitive materials and X-ray spectroscopy compatible photoelectrochemical (PEC) cells. The mobile system is currently deployed at the Advanced Light Source (ALS) and may be used in all operating modes (two-bunch and multi-bunch) of the synchrotron. The use of a time-stamping technique enables the simultaneous recording of TRXAS spectra with delays between the exciting laser pulses and the probing X-ray pulses spanning picosecond to nanosecond temporal scales. First results are discussed that demonstrate the viability of the method to study photoinduced dynamics in transition metal-oxide semiconductor (SC) samples under high vacuum conditions and at SC-liquid electrolyte interfaces during photoelectrochemical water splitting. Opportunities and challenges are outlined to capture crucial short-lived intermediates of photochemical processes with the technique. This work was supported by the Department of Energy Office of Science Early Career Research Program.

  13. Non-invasive gas monitoring in newborn infants using diode laser absorption spectroscopy: a case study

    Science.gov (United States)

    Lundin, Patrik; Svanberg, Emilie K.; Cocola, Lorenzo; Lewander, Märta; Andersson-Engels, Stefan; Jahr, John; Fellman, Vineta; Svanberg, Katarina; Svanberg, Sune

    2012-03-01

    Non-invasive diode laser spectroscopy was, for the first time, used to assess gas content in the intestines and the lungs of a new-born, 4 kg, baby. Two gases, water vapor and oxygen, were studied with two low-power tunable diode lasers, illuminating the surface skin tissue and detecting the diffusely emerging light a few centimeters away. The light, having penetrated into the tissue, had experienced absorption by gas located in the lungs and in the intestines. Very distinct water vapor signals were obtained from the intestines while imprint from oxygen was lacking, as expected. Detectable, but minor, signals of water vapor were also obtained from the lungs, illuminating the armpit area and detecting below the collar bone. Water vapor signals were seen but again oxygen signals were lacking, now due to the difficulties of penetration of the oxygen probing light into the lungs of this full-term baby. Ultra-sound images were obtained both from the lungs and from the stomach of the baby. Based on dimensions and our experimental findings, we conclude, that for early pre-term babies, also oxygen should be detectable in the lungs, in addition to intestine and lung detection of water vapor. The present paper focuses on the studies of the intestines while the lung studies will be covered in a forthcoming paper.

  14. Studies of ionic liquid solutions by soft X-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Fabio [Departamento de Quimica Fundamental, Instituto de Quimica, Universidade de Sao Paulo, CP 26.077, CEP 05513-970, Sao Paulo, SP (Brazil); Nascimento, Gustavo M. do [Departamento de Quimica Fundamental, Instituto de Quimica, Universidade de Sao Paulo, CP 26.077, CEP 05513-970, Sao Paulo, SP (Brazil)], E-mail: morari@yahoo.com; Santos, Paulo S. [Departamento de Quimica Fundamental, Instituto de Quimica, Universidade de Sao Paulo, CP 26.077, CEP 05513-970, Sao Paulo, SP (Brazil)

    2007-03-15

    Soft X-ray spectroscopies give specific information about the electronic structure around light elements. The high absorption of soft X-rays by almost every molecule, including air, requires studies under vacuum, which represents a great limitation. Solids with high vapor pressure and liquids are very difficult to be studied, making solution chemistry almost neglected. This work explores the use of ionic liquids, organic liquids with very low vapor pressure, as media to study chemical solutions using soft X-ray. N 1s spectra are reported of ionic liquid solutions of 1-methyl-3alkyl-imidazolium cation with different anions and chain lengths, and urea/choline chloride mixtures (a deep eutectic solvent) with several solutes including dyes (Janus Green B and Congo Red), synthetic polymers (polyaniline) and nitrate salts. While there are significant problems with the signal of the solvent, the results do show that it is possible to detect solute signals, and further to see spectral changes attributed to solvent-solute interactions.

  15. Spectrophotometric study of interaction of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone with diaza-18-crown-6 and diaza-15-crown-5 in acetonitrile and chloroform solutions

    Science.gov (United States)

    Hasani, Masoumeh; Shamsipur, Mojtaba

    2005-03-01

    Interactions of diaza-18-crown-6 and diaza-15-crown-5, as electron donors, with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), as an electron acceptor, have been investigated spectrophotometrically in acetonitrile and chloroform solutions. The results indicated immediate formation of an electron donor-electron acceptor complex DA: D+A ⇌fastKDA which is followed by two relatively slow consecutive reactions: DA⟶kDA⟶kProduct The pseudo-first-order rate constants for the formation of the ionic intermediate and the final product have been evaluated at various temperatures by computer fitting of the absorbance time data to appropriate equations. The formation constants of the resulting DA complexes have also been determined. The influences of both the azacrown's structure and the solvent properties on the formation of DA complexes and the rates of subsequent reactions are discussed.

  16. Successive spectrophotometric resolution as a novel technique for the analysis of ternary mixtures of pharmaceuticals

    Science.gov (United States)

    Lotfy, Hayam M.; Tawakkol, Shereen M.; Fahmy, Nesma M.; Shehata, Mostafa A.

    2014-03-01

    A novel spectrophotometric technique was developed for the simultaneous determination of ternary mixtures, without prior separation steps. This technique was called successive spectrophotometric resolution technique. The technique was based on either the successive ratio subtraction or successive derivative subtraction. The mathematical explanation of the procedure was illustrated. In order to evaluate the applicability of the methods a model data as well as an experimental data were tested. The results from experimental data related to the simultaneous spectrophotometric determination of lidocaine hydrochloride (LH), calcium dobesilate (CD) and dexamethasone acetate (DA); in the presence of hydroquinone (HQ), the degradation product of calcium dobesilate were discussed. The proposed drugs were determined at their maxima 202 nm, 305 nm, 239 nm and 225 nm for LH, CD, DA and HQ respectively; by successive ratio subtraction coupled with constant multiplication method to obtain the zero order absorption spectra, while by applying successive derivative subtraction they were determined at their first derivative spectra at 210 nm for LH, 320 nm or P292-320 for CD, 256 nm or P225-252 for DA and P220-233 for HQ respectively. The calibration curves were linear over the concentration range of 2-20 μg/mL for both LH and DA, 6-50 μg/mL for CD, and 3-40 μg/mL for HQ. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs with no interference from other dosage form additives. The proposed methods were validated according to the ICH guidelines. The obtained results were statistically compared with those of the official BP methods for LH, DA, and CD, and with the official USP method for HQ; using student t-test, F-test, and one way ANOVA, showing no significant difference with respect to accuracy and precision.

  17. Improved Spectrophotometric Calibration of the SDSS-III BOSS Quasar Sample

    OpenAIRE

    Margala, Daniel; Kirkby, David; Dawson, Kyle; Bailey, Stephen; Blanton, Michael; Schneider, Donald P.

    2015-01-01

    We present a model for spectrophotometric calibration errors in observations of quasars from the third generation of the Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) and describe the correction procedure we have developed and applied to this sample. Calibration errors are primarily due to atmospheric differential refraction and guiding offsets during each exposure. The corrections potentially reduce the systematics for any studies of BOSS quasars, includi...

  18. NEW VISIBLE SPECTROPHOTOMETRIC METHOD FOR ESTIMATION OF ITOPRIDE HYDROCHLORIDE FROM TABLETS FORMULATIONS USING METHYL ORANGE REAGENT

    Directory of Open Access Journals (Sweden)

    BALRAM CHOUDHARY

    2009-07-01

    Full Text Available A simple, economical, precise and fast visible spectrophotometric method has been developed for the determination of Itopride hydrochloride in tablet dosage form. Developed method is based on the formation of extractable colored complex of drug with coloring agent Methyl orange. A wavelength maximum was found to be 418.5 nm. Linearity was observed in the concentration range of 10-50 g /ml. The result of analysis have been validated statistically and also by recovery studies.

  19. Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate

    OpenAIRE

    Gouda, Ayman Abou El-Fetouh; El-Sheikh, Ragaa; El Shafey, Zeineb.; Hossny, Nagda.; El-Azzazy, Rham

    2008-01-01

    Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), ...

  20. SIMULTANEOUS ESTIMATION OF ABACAVIR, LAMIVUDINE AND ZIDOVUDINE IN COMBINED TABLET DOSAGE FORM BY UV SPECTROPHOTOMETRIC METHOD

    OpenAIRE

    Nagulwar Vaishali P; Bhusari Kishor P

    2011-01-01

    The present study deals with the development of an accurate, economical and reproducible UV spectrophotometric method for the simultaneous estimation of abacavir, lamivudine and zidovudine in pure bulk drug and in combined tablet dosage form. The stock solutions were prepared in acetonitrile followed by the further required dilutions with distilled water. The λ max for abacavir, lamivudine, and zidovudine were observed at 295.6, 279.8 and 266.2 nm respectively and linearity was also shown at ...

  1. Simultaneous derivative and multi-component spectrophotometric determination of drotaverine hydrochloride and mefenamic acid in tablets

    Directory of Open Access Journals (Sweden)

    Dahivelkar P

    2007-01-01

    Full Text Available Two new, simple, accurate and economical spectrophotometric methods have been developed for simultaneous estimation of drotaverine hydrochloride and mefenamic acid in two-component tablet formulation. The methods employed are, first derivative spectrophotometry, using zero crossing technique and multicomponent analysis. Both the drugs obey the Beer′s law in the concentration range employed for these methods. The results of analysis are validated by statistical evaluation and recovery studies.

  2. High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue

    Energy Technology Data Exchange (ETDEWEB)

    Collingwood, J.F.; Mikhaylova, A.; Davidson, M.R.; Batich, C.; Streit, W.J.; Eskin, T.; Terry, J.; Barrea, R.; Underhill, R.S.; Dobson, J. (IIT); (Keele); (Florida); (DRDC)

    2008-06-16

    Fluorescence mapping and microfocus X-ray absorption spectroscopy are used to detect, locate and identify iron biominerals and other inorganic metal accumulations in neurodegenerative brain tissue at sub-cellular resolution (< 5 microns). Recent progress in developing the technique is reviewed. Synchrotron X-rays are used to map tissue sections for metals of interest, and XANES and XAFS are used to characterize anomalous concentrations of the metals in-situ so that they can be correlated with tissue structures and disease pathology. Iron anomalies associated with biogenic magnetite, ferritin and haemoglobin are located and identified in an avian tissue model with a pixel resolution {approx} 5 microns. Subsequent studies include brain tissue sections from transgenic Huntington's mice, and the first high-resolution mapping and identification of iron biominerals in human Alzheimer's and control autopsy brain tissue. Technical developments include use of microfocus diffraction to obtain structural information about biominerals in-situ, and depositing sample location grids by lithography for the location of anomalies by conventional microscopy. The combined techniques provide a breakthrough in the study of both intra- and extra-cellular iron compounds and related metals in tissue. The information to be gained from this approach has implications for future diagnosis and treatment of neurodegeneration, and for our understanding of the mechanisms involved.

  3. Shock tube/laser absorption studies of the decomposition of methyl formate

    KAUST Repository

    Ren, Wei

    2013-01-01

    Reaction rate coefficients for the major high-temperature methyl formate (MF, CH3OCHO) decomposition pathways, MF → CH3OH + CO (1), MF →CH2O+CH2O (2), and MF→ CH4 + CO2 (3), were directly measured in a shock tube using laser absorption of CO (4.6 μm), CH2O (306 nm) and CH4 (3.4 μm). Experimental conditions ranged from 1202 to 1607 K and 1.36 to 1.72 atm, with mixtures varying in initial fuel concentration from 0.1% to 3% MF diluted in argon. The decomposition rate coefficients were determined by monitoring the formation rate of each target species immediately behind the reflected shock waves and modeling the species time-histories with a detailed kinetic mechanism [12]. The three measured rate coefficients can be well-described using two-parameter Arrhenius expressions over the temperature range in the present study: k1 = 1.1 × 1013 exp(-29556/T, K) s -1, k2 = 2.6 × 1012 exp(-32052/T, K) s-1, and k3 = 4.4 × 1011 exp(-29 078/T, K) s-1, all thought to be near their high-pressure limits. Uncertainties in the k1, k2 and k3 measurements were estimated to be ±25%, ±35%, and ±40%, respectively. We believe that these are the first direct high-temperature rate measurements for MF decomposition and all are in excellent agreement with the Dooley et al. [12] mechanism. In addition, by also monitoring methanol (CH3OH) and MF concentration histories using a tunable CO2 gas laser operating at 9.67 and 9.23 μm, respectively, all the major oxygen-carrying molecules were quantitatively detected in the reaction system. An oxygen balance analysis during MF decomposition shows that the multi-wavelength laser absorption strategy used in this study was able to track more than 97% of the initial oxygen atoms in the fuel. © 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  4. Nasal Drug Delivery : In Vitro Studies on Factors Influencing Permeability and Implications on Absorption

    OpenAIRE

    Wadell, Cecilia

    2002-01-01

    Nasal delivery is a feasible alternative to oral or parenteral administration for some drugs because of the high permeability of the nasal epithelium, rapid drug absorption across this membrane and avoidance of hepatic first-pass metabolism. The main objective of this thesis was to investigate factors influencing the permeability of the nasal mucosa to various compounds and to evaluate implications for drug absorption via the nasal route. Porcine nasal mucosa mounted in an Ussing chamber sys...

  5. SPECTROPHOTOMETRIC ESTIMATION OF MONTELUKAST FROM BULK DRUG AND TABLET DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    S.R. Bhagade

    2013-11-01

    Full Text Available Two Simple, accurate, precise and sensitive spectrophotometric methods for estimation of Montelukast sodium (MON have been developed and validated. The zero order spectroscopic method (Method I and area under curve method (Method II have developed. The proposed methods are validated according to ICH Q2B guidelines. The Montelukast sodium gives maximum absorbance at 241nm in chloroform and observed linearity 2-20 μg/ml for zero order method and 4-20 μg/ml for area under curve method. The stability of drug in chloroform has been studied and drug shows good stability in Chloroform. The recovery by method I and method II are 99.52 ± 0.069, 101.93± 0.11 respectively. The both spectrophotometric methods can be applied for routine analysis of Montelukast sodium in tablet formulation and in bulk drug.

  6. Kinetic spectrophotometric method for the determination of norfloxacin in pharmaceutical formulations.

    Science.gov (United States)

    Rahman, Nafisur; Ahmad, Yasmin; Hejaz Azmi, Syed Najmul

    2004-03-01

    A simple and sensitive kinetic spectrophotometric method is described, based on the oxidation of norfloxacin with alkaline potassium permanganate. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 603 nm. The initial rate and fixed time (at 3 min) methods are utilized for constructing the calibration graphs to determine the concentration of the drug. The calibration graphs are linear in the concentration ranges 2.0-20 microg ml(-1) and 1.0-20 microg ml(-1) using the initial rate and fixed time methods, respectively. The results are validated statistically and through recovery studies. The method has been successfully applied to the determination of norfloxacin in commercial dosage forms. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision. PMID:15018997

  7. Ultrafast Time-Resolved Emission and Absorption Spectra of meso-Pyridyl Porphyrins upon Soret Band Excitation Studied by Fluorescence Up-Conversion and Transient Absorption Spectroscopy.

    Science.gov (United States)

    Venkatesh, Yeduru; Venkatesan, M; Ramakrishna, B; Bangal, Prakriti Ranjan

    2016-09-01

    A comprehensive study of ultrafast molecular relaxation processes of isomeric meso-(pyridyl) porphyrins (TpyPs) has been carried out by using femtosecond time-resolved emission and absorption spectroscopic techniques upon pumping at 400 nm, Soret band (B band or S2), in 4:1 dichloromethane (DCM) and tetrahydrofuran (THF) solvent mixture. By combined studies of fluorescence up-conversion, time-correlated single photon counting, and transient absorption spectroscopic techniques, a complete model with different microscopic rate constants associated with elementary processes involved in electronic manifolds has been reported. Besides, a distinct coherent nuclear wave packet motion in Qy state is observed at low-frequency mode, ca. 26 cm(-1) region. Fluorescence up-conversion studies constitute ultrafast time-resolved emission spectra (TRES) over the whole emission range (430-710 nm) starting from S2 state to Qx state via Qy state. Careful analysis of time profiles of up-converted signals at different emission wavelengths helps to reveal detail molecular dynamics. The observed lifetimes are as indicated: A very fast decay component with 80 ± 20 fs observed at ∼435 nm is assigned to the lifetime of S2 (B) state, whereas being a rise component in the region of between 550 and 710 nm emission wavelength pertaining to Qy and Qx states, it is attributed to very fast internal conversion (IC) occurring from B → Qy and B → Qx as well. Two distinct components of Qy emission decay with ∼200-300 fs and ∼1-1.5 ps time constants are due to intramolecular vibrational redistribution (IVR) induced by solute-solvent inelastic collisions and vibrational redistribution induced by solute-solvent elastic collision, respectively. The weighted average of these two decay components is assigned as the characteristic lifetime of Qy, and it ranges between 0.3 and 0.5 ps. An additional ∼20 ± 2 ps rise component is observed in Qx emission, and it is assigned to the formation time of

  8. Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

    KAUST Repository

    Elwardany, A.

    2014-07-16

    The thermal decomposition of formic acid (HCOOH) and acetic acid (CH3COOH), two carboxylic acids which play an important role in oxygenate combustion chemistry, were investigated behind reflected shock waves using laser absorption. The rate constants of the primary decomposition pathways of these acids:(HCOOH → CO + H2 O (R 1); HCOOH → CO2 + H2 (R 2); CH3 COOH → CH4 + CO2 (R 3); CH3 COOH → CH2 CO + H2 O (R 4)) were measured using simultaneous infrared laser absorption of CO, CO2 and H2O at wavelengths of 4.56, 4.18 and 2.93 microns, respectively. Reaction test conditions covered temperatures from 1230 to 1821 K and pressures from 1.0 to 6.5 atm for dilute mixtures of acids (0.25-0.6%) in argon. The rate constants of dehydration (R1) and decarboxylation (R2) reactions of formic acid were calculated by fitting exponential functions to the measured CO, CO2 and H2O time-history profiles. These two decomposition channels were found to be in the fall-off region and have a branching ratio, k1/k2, of approximately 20 over the range of pressures studied here. The best-fit Arrhenius expressions of the first-order rates of R1 and R2 were found to be:(k1 (1 atm) = 1.03 × 1011 exp (- 25651 / T) s- 1 (± 37 %); k1 (6.5 atm) = 9.12 × 1012 exp (- 30275 / T) s- 1 (± 32 %); k2 (1 atm) = 1.79 × 108 exp (- 21133 / T) s- 1 (± 41 %); k2 (6.5 atm) = 2.73 × 108 exp (- 20074 / T) s- 1 (± 37 %)). The rate constants for acetic acid decomposition were obtained by fitting simulated profiles, using an acetic acid pyrolysis mechanism, to the measured species time-histories. The branching ratio, k4/k3, was found to be approximately 2. The decarboxylation and dehydration reactions of acetic acid appear to be in the falloff region over the tested pressure range:(k3 (1 atm) = 3.18 × 1011 exp (- 28679 / T) s- 1 (± 30 %); k3 (6 atm) = 3.51 × 1012 exp (- 31330 / T) s- 1 (± 26 %); k4 (1 atm) = 7.9 × 1011 exp (- 29056 / T) s- 1 (± 34 %); k4 (6 atm) = 6.34 × 1012 exp (- 31330 / T) s

  9. A study on the inhibitory mechanism for cholesterol absorption by α-cyclodextrin administration

    Directory of Open Access Journals (Sweden)

    Takahiro Furune

    2014-12-01

    Full Text Available Background: Micelle formation of cholesterol with lecithin and bile salts is a key process for intestinal absorption of lipids. Some dietary fibers commonly used to reduce the lipid content in the body are thought to inhibit lipid absorption by binding to bile salts and decreasing the lipid solubility. Amongst these, α-cyclodextrin (α-CD is reportedly one of the most powerful dietary fibers for decreasing blood cholesterol. However, it is difficult to believe that α-CD directly removes cholesterol because it has a very low affinity for cholesterol and its mechanism of action is less well understood than those of other dietary fibers. To identify this mechanism, we investigated the interaction of α-CD with lecithin and bile salts, which are essential components for the dissolution of cholesterol in the small intestine, and the effect of α-CD on micellar solubility of cholesterol.Results: α-CD was added to Fed-State Simulated Intestinal Fluid (FeSSIF, and precipitation of a white solid was observed. Analytical data showed that the precipitate was a lecithin and α-CD complex with a molar ratio of 1:4 or 1:5. The micellar solubility of cholesterol in the mixture of FeSSIF and α-CD was investigated, and found to decrease through lecithin precipitation caused by the addition of α-CD, in a dose-dependent manner. Furthermore, each of several other water-soluble dietary fibers was added to the FeSSIF, and no precipitate was generated.Conclusion: This study suggests that α-CD decreases the micellar solubility of cholesterol in the lumen of the small intestine via the precipitation of lecithin from bile salt micelles by complex formation with α-CD. It further indicates that the lecithin precipitation effect on the bile salt micelles by α-CD addition clearly differs from addition of other water-soluble dietary fibers. The decrease in micellar cholesterol solubility in the FeSSIF was the strongest with α-CD addition.

  10. Study about the capillary absorption and the sorptivity of concretes with Cuban limestone aggregates

    Directory of Open Access Journals (Sweden)

    Howland, J. J.

    2013-12-01

    Full Text Available The objective of this study was to demonstrate the possibility to obtain concretes in Cuba with values of effective porosity below of 10%, using limestone aggregates with high levels of absorption (higher than 1% in many cases, and values of Sorptivity below of 5 x 10-5 m/s1/2 as is established in the document prepared by the DURAR Latin Working Group, for structures exposed to very aggressive environments. The experimental results showed that the use of the trial method of capillary absorption of Göran Fagerlund, were obtained concretes with effective porosity below of the 10%, for water/cement ratios of 0.4 and 0.45, but the values of sorptivities were very high. Nevertheless the subsequent use of the trial method of the ASTM C1585, that use cylinders probes with bigger depth and different processing, permits to obtain the desired sorptivity values for water/cement ratios of 0.4 and 0.45 whenever would be fulfilled the Good Practices of the Construction.El objetivo del estudio fue demostrar la posibilidad de lograr en Cuba, con el empleo de áridos calizos de elevada absorción (mayores del 1% en muchos casos, hormigones con valores de porosidad efectiva inferiores al 10% y de velocidad de absorción capilar (Sorptividad inferiores a 5 x 10-5 m/s1/2, tal como establece el documento elaborado por la RED DURAR del CYTED para estructuras expuestas a ambientes muy agresivos. Los resultados experimentales mostraron que con la aplicación del método de ensayo de absorción capilar de Göran Fagerlund se obtuvieron porosidades efectivas inferiores al 10% para relaciones agua/cemento de 0,4 y 0,45, pero los valores de sorptividad fueron muy elevados. No obstante la aplicación posterior del método de ensayo de la ASTM C1585 que utiliza probetas de mayor espesor y diferente tratamiento, permitió obtener los valores indicados de sorptividad para relaciones agua/cemento de 0,4; 0,45 siempre que se cumplan las Buenas Prácticas constructivas.

  11. Spectral studies of ocean water with space-borne sensor SCIAMACHY using Differential Optical Absorption Spectroscopy (DOAS

    Directory of Open Access Journals (Sweden)

    M. Vountas

    2007-09-01

    Full Text Available Methods enabling the retrieval of oceanic parameter from the space borne instrumentation Scanning Imaging Absorption Spectrometer for Atmospheric ChartographY (SCIAMACHY using Differential Optical Absorption Spectroscopy (DOAS are presented. SCIAMACHY onboard ENVISAT measures back scattered solar radiation at a spectral resolution (0.2 to 1.5 nm. The DOAS method was used for the first time to fit modelled Vibrational Raman Scattering (VRS in liquid water and in situ measured phytoplankton absorption reference spectra to optical depths measured by SCIAMACHY. Spectral structures of VRS and phytoplankton absorption were clearly found in these optical depths. Both fitting approaches lead to consistent results. DOAS fits correlate with estimates of chlorophyll concentrations: low fit factors for VRS retrievals correspond to large chlorophyll concentrations and vice versa; large fit factors for phytoplankton absorption correspond with high chlorophyll concentrations and vice versa. From these results a simple retrieval technique taking advantage of both measurements is shown. First maps of global chlorophyll concentrations were compared to the corresponding MODIS measurements with very promising results. In addition, results from this study will be used to improve atmospheric trace gas DOAS-retrievals from visible wavelengths by including these oceanographic signatures.

  12. A Groundbased Imaging Study of Galaxies Causing DLA, subDLA, and LLS Absorption in Quasar Spectra

    CERN Document Server

    Rao, Sandhya M; Turnshek, David A; Monier, Eric M; Nestor, Daniel B; Quider, Anna M

    2011-01-01

    We present results from a search for galaxies that give rise to damped Lyman alpha (DLA), subDLA, and Lyman limit system (LLS) absorption at redshifts 0.1 ~= 0.3 A) whose HI column densities were determined by measuring the Ly-alpha line in HST UV spectra. Photometric redshifts, galaxy colors, and proximity to the quasar sightline, in decreasing order of importance, were used to identify galaxies responsible for the absorption. Our sample includes 80 absorption systems for which the absorbing galaxies have been identified, of which 54 are presented here for the first time. The main results of this study are: (i) the surface density of galaxies falls off exponentially with increasing impact parameter, b, from the quasar sightline relative to a constant background of galaxies, with an e-folding length of ~46 kpc. Galaxies with b >~ 100 kpc calculated at the absorption redshift are statistically consistent with being unrelated to the absorption system. (ii) log N(HI) is inversely correlated with b at the 3.0 sig...

  13. Parametric Study of Differential Absorption Lidar Systemfor Monitoring Toxic Agents in the Atmosphere

    Directory of Open Access Journals (Sweden)

    S. Veerabuthiran

    2007-09-01

    Full Text Available Differential absorption lidar (DIAL techniques are advantageously used these days fordetecting and monitoring traces of toxic agents located at several kilometer in the atmosphere.A theoretical study has been carried out to simulate the performance of a multiwavelength DIALsystem. Clouds of hydrazine, unsymmetrical dimethylhydrazine (UDMH, andmonomethylhydrazine (MMH, located at various ranges up to 5 km in the atmosphere, havebeen taken as examples of the toxic agents. It has been shown that a given lidar system cannotdetect any of these agents with a specific cloud thickness if the concentration of that agent isbelow a certain value (Nmin. It has also been shown that if the concentration level of a givenagent is above a certain value (Nmax at a particular distance, this value cannot be quantified fora given lidar system although the identity as well as the location of that agent can still bedetermined. Further, for some typical parametric conditions, the required energy levels of thelaser to detect specific concentrations of these agents at different distances have been computed.Power levels of the return signals and the SNR values from different ranges have also beencalculated for each of these toxic agents for a given value of the laser transmitter energy.

  14. Iron in Alzheimer's and Control Hippocampi - Moessbauer, Atomic Absorption and ELISA Studies

    International Nuclear Information System (INIS)

    Alzheimer disease is a neurodegenerative process of unknown mechanism taking place in a part of the brain - hippocampus. Oxidative stress and the role of iron in it is one of the suggested mechanisms of cells death. In this study several methods were used to assess iron and iron binding compounds in human hippocampus tissues. Moessbauer spectroscopy was used for identification of the iron binding compound and determination of total iron concentration in 12 control and one Alzheimer disease sample of hippocampus. Moessbauer parameters obtained for all samples suggest that most of the iron is ferritin-like iron. The average concentration of iron determined by Moessbauer spectroscopy in control hippocampus was 45 ± 10 ng/mg wet tissue. The average concentration of iron in 10 Alzheimer disease samples determined by atomic absorption was 66 ± 13 ng/mg wet tissue. The concentration of H and L chains of ferritin in 20 control and 10 AD hippocampi was assessed with enzyme-linked immuno-absorbent assay. The concentration of H and L ferritin was higher in Alzheimer disease compared to control (19.36 ± 1.51 vs. 5.84 ± 0.55 ng/μg protein for H, and 1.39 ± 0.25 vs. 0.55 ± 0.10 for L). This 3-fold increase of the concentration of ferritin is accompanied by a small increase of the total iron concentration. (authors)

  15. Brush border membrane vesicles from dipteran midgut: a tool for studies on nutrient absorption

    Directory of Open Access Journals (Sweden)

    MG Leonardi

    2006-12-01

    Full Text Available Brush border membrane vesicles (BBMV from insects midgut can be successfully used to study several membrane phenomena, including nutrient absorption, ions permeability and insecticides mode of action. Midgut BBMV, purified from Musca domestica whole larvae, were used for the functional characterization of leucine transport. The amino acid uptake was accelerated in the presence of sodium or potassium and increased significantly when the extravesicular pH was 5.0, in agreement with the luminal pH in vivo. Radiolabelled leucine uptake was significantly reduced by an excess of cold leucine, histidine, serine and glycine, suggesting that the amino acid transporter is a broad scope carrier that does not recognize proline, glutamine and the dibasic amino acids lysine and arginine.Midgut BBMV were also obtained from homogenization of M. domestica and Bactrocera oleae adults. The final preparations showed a high enrichment in the specific activity of the BBM marker enzymes aminopeptidase N and γ-glutamyl transpeptidase, and were poorly contaminated by basolateral membranes, as indicated by the low specific activities of their marker enzyme Na+/K+ ATPase. Electron microscopy of B. oleae BBM fraction showed the presence of closed vesicles. Similar SDS-PAGE patterns, with numerous distinct bands, were detected for both B. oleae and M. domestica BBMV.

  16. Study of Water Absorption in Raffia vinifera Fibres from Bandjoun, Cameroon

    Directory of Open Access Journals (Sweden)

    N. R. Sikame Tagne

    2014-01-01

    Full Text Available The study is focused on the water diffusion phenomenon through the Raffia vinifera fibre from the stem. The knowledge on the behavior of those fibres in presence of liquid during the realization of biocomposite, is necessary. The parameters like percentage of water gain at the point of saturation, modelling of the kinetic of water absorption, and the effective diffusion coefficient were the main objectives. Along a stem of raffia, twelve zones of sampling were defined. From Fick’s 2nd law of diffusion, a new model was proposed and evaluated compared to four other models at a constant temperature of 23°C. From the proposed model, the effective diffusion coefficient was deduced. The percentage of water gain was in the range of 303–662%. The proposed model fitted better to the experimental data. The estimated diffusion coefficient was evaluated during the initial phase and at the final phase. In any cross section located along the stem of Raffia vinifera, it was found that the effective diffusion coefficient increases from the periphery to the centre during the initial and final phases.

  17. OPTIMIZING CONDITIONS FOR SPECTROPHOTOMETRIC DETERMINATION OF TOTAL POLYPHENOLS IN WINES USING FOLIN-CIOCALTEU REAGENT

    Directory of Open Access Journals (Sweden)

    Daniel Bajčan

    2013-02-01

    Full Text Available Wine is a complex beverage that obtains its properties mainly due to synergistic effect of alcohol, organic acids, arbohydrates, as well as the phenolic and aromatic substances. At present days, we can observe an increased interest in the study of polyphenols in wines that have antioxidant, antimicrobial, anti-inflammatory, anti-cancer and many other beneficial effects. Moderate and regular consumption of the red wine especially, with a high content of phenolic compounds, has a beneficial effect on human health. The aim of this work was to optimize conditions for spectrophotometric determination of total polyphenols in winwas to optimize conditions for spectrophotometric determination of total polyphenols in winwas to optimize conditions for spectrophotometric determination of total polyphenols in winwas to optimize conditions for pectrophotometric determination of total polyphenols in wine using Folin-Ciocaulteu reagent. Based on several studies, in order to minimize chemical use and optimize analysis time, we have proposed a method for the determination of total polyphenols using 0.25 ml Folin-Ciocaulteu reagent, 3 ml of 20% Na2CO3 solution and time of coloring complex 1.5 hour. We f

  18. Laser plasma interaction studies in the context of shock ignition--Transition from collisional to collisionless absorption

    Energy Technology Data Exchange (ETDEWEB)

    Klimo, O. [Czech Technical University in Prague, FNSPE, Brehova 7, Prague 11519 (Czech Republic); Centre Lasers Intenses et Applications, University Bordeaux 1-CEA-CNRS, Talence 33405 (France); Tikhonchuk, V. T.; Ribeyre, X.; Schurtz, G.; Weber, S. [Centre Lasers Intenses et Applications, University Bordeaux 1-CEA-CNRS, Talence 33405 (France); Riconda, C. [TIPS/LULI, Universite Paris 6, CNRS, CEA, Ecole Polytechnique, Ivry-sur-Seine 94200 (France); Limpouch, J. [Czech Technical University in Prague, FNSPE, Brehova 7, Prague 11519 (Czech Republic)

    2011-08-15

    The shock ignition concept implies laser pulse intensities higher than 10{sup 15} W/cm{sup 2} (at the wavelength of 351 nm), which is the commonly accepted limit where the inverse bremsstruhlung absorption dominates. The transition from collisional to collisionless absorption in laser plasma interactions at higher intensities is studied in the present paper with the help of large scale one-dimensional particle-in-cell simulations. The initial parameters are defined by the hydrodynamic simulations corresponding to recent experiments. The simulations predict that a quasi-steady regime of laser plasma interaction is attained where the total laser energy absorption stays on the level of {approx}65% in the laser intensity range 10{sup 15}-10{sup 16} W/cm{sup 2}. However, the relation between the collisional and collisionless processes changes significantly. This is manifested in the energy spectrum of electrons transporting the absorbed laser energy and in the spectrum of the reflected laser light.

  19. Shapes of the $^{192,190}$Pb ground states from beta decay studies using the total absorption technique

    CERN Document Server

    Aguado, M E Estevez; Agramunt, J; Rubio, B; Tain, J L; Jordan, D.; Fraile, L M; Gelletly, W; Frank, A.; Csatlos, M.; Csige, L; Dombradi, Zs.; Krasznahorkay, A; Nacher, E; Sarriguren, P; Borge, M J G; Briz, J A; Tengblad, O; Molina, F.; Moreno, O; Kowalska, M; Fedosseev, V N; Marsh, B A; Fedorov, D V; Molkanov, P L; Andreyev, A.N.; Seliverstov, M D; Burkard, K; Huller, W

    2015-01-01

    The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.

  20. Study of electronic structures and absorption bands of BaMgF4 crystal with F colour centre

    Institute of Scientific and Technical Information of China (English)

    Kang Ling-Ling; Liu Ting-Yu; Zhang Qi-Ren; Xu Ling-Zhi; Zhang Fei-Wu

    2011-01-01

    The electronic structures of BaMgF4 crystals containing an F colour centre are studied within the framework of the fully relativistic self-consistent Direc-Slate-theory, using a numerically discrete variational (DV-Xα)method. It is concluded from the calculated results that the energy levels of the F colour centre are located in the forbidden band.The optical transition energy from the ground state to the excited state for the F colour centre is about 5.12 eV, which corresponds to the 242-nm absorption band. These calculated results can explain the origin of the absorption bands.

  1. Theoretical Studies on the Third-order Nonlinear Optical Properties and Two-photon Absorption of Stilbene Derivatives

    Institute of Scientific and Technical Information of China (English)

    REN, Ai-Min(任爱民); FENG, Ji-Kang(封继康); LIU, Xiao-Juan(刘孝娟)

    2004-01-01

    Different types of stilbene derivatives (D-π-D, A-π-A, D-π-A) were investigated with AM1, and specially, equilibrium geometries of symmetrical stilbene derivatives (D-π-D) were studied using of PM3. With the same method INDO/CI, the UV-vis spectra were explored and the position and strength of the two-photon absorption were predicated by Sum-Over-States expression. The relationships of the structures, spectra and nonlinear optical properties have been examined. The influence of various substituents on two photon absorption cross-sections was discussed micromechanically.

  2. Spectrophotometric Examination of Rough Print Surfaces

    Directory of Open Access Journals (Sweden)

    Erzsébet Novotny

    2011-05-01

    Full Text Available The objective was to assess the impact of the surface texture of individual creative paper types (coated or patternedon the quality of printing and to identify to what extent the various creative paper types require specific types ofspectrophotometers. We used stereomicroscopic images to illustrate unprinted and printed surfaces of creative papertypes. Surface roughness was measured to obtain data on the unevenness of surfaces. Spectrophotometric tests wereused to select the most suitable spectrophotometer from meters with different illumination setup for testing anygiven print. For the purpose of testing, we used spectrophotometers which are commonly available generally used totest print products for colour accuracy. With the improvement of measuring geometries, illumination setup, colourmeasurement becomes more and more capable of producing reliable results unaffected by surface textures. Our testshave proved this fact by showing that the GretagMacbeth Spectrolino with annular illumination is less sensitive tosurface texture than the X-Rite Spetrodensitometer and the Techkon SpetroDens with directional illumination. Furthertests have brought us to the conclusion that there is a difference even between the two devices with directionalillumination. While the X-Rite 530 Spectrodensitometer is more suitable for testing coated surfaces, the TechkonSpectroDens can come close to ΔE*ab values produced by the annular illuminated device for textured surfaces.

  3. An Atlas of Spectrophotometric Landolt Standard Stars

    Science.gov (United States)

    Stritzinger, Maximilian; Suntzeff, Nicholas B.; Hamuy, Mario; Challis, Peter; Demarco, Ricardo; Germany, Lisa; Soderberg, A. M.

    2005-08-01

    We present CCD observations of 102 Landolt standard stars obtained with the Ritchey-Chrétien spectrograph on the Cerro Tololo Inter-American Observatory 1.5 m telescope. Using stellar atmosphere models, we have extended the flux points to our six spectrophotometric secondary standards, in both the blue and the red, allowing us to produce flux-calibrated spectra that span a wavelength range from 3050 Å to 1.1 μm. Mean differences between UBVRI spectrophotometry computed using Bessell's standard passbands and Landolt's published photometry were determined to be 1% or less. Observers in both hemispheres will find these spectra useful for flux-calibrating spectra, and through the use of accurately constructed instrumental passbands, will be able to compute accurate corrections to bring instrumental magnitudes to any desired standard photometric system (S-corrections). In addition, by combining empirical and modeled spectra of the Sun, Sirius, and Vega, we calculate and compare synthetic photometry to observed photometry taken from the literature for these three stars.

  4. Bimetallic Catalysts and Platinum Surfaces Studied by X-ray Absorption Spectroscopy and Scanning Tunnelling Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roenning, Magnus

    2000-07-01

    Bimetallic catalyst systems used in Fischer-Tropsch synthesis (Co-Re/Al{sub 2}O{sub 3}) and in the naphtha reforming process (Pt-Re/Al{sub 2}O{sub 3}) have been studied in situ using X-ray absorption spectroscopy (EXAFS). Additionally, the adsorption of ethene on platinum single crystal surfaces has been investigated using scanning tunnelling microscopy. In situ EXAFS at the cobalt K absorption edge have been carried out at 450{sup o}C on the hydrogen reduction of a rhenium-promoted Co{sub 3}O{sub 4}/Al{sub 2}O{sub 3} catalyst. Reductions carried out using 100% hydrogen and 5% hydrogen in helium gave different results. Whereas the reduction using dilute hydrogen leads to bulk-like metallic cobalt particles (hcp or fcc), reaction with pure hydrogen yields a more dispersed system with smaller cobalt metal particles (< 40 A). The results are rationalised in terms of different degrees of reoxidation of cobalt by the higher and lower concentrations of water generated during the reduction of cobalt oxide by 100% and 5% hydrogen, respectively. Additionally, in both reduction protocols a small fraction (3 -4 wt%) of the cobalt content is randomly dispersed over the tetrahedral vacancies of the alumina support. This dispersion occurs during reduction and not calcination. The cobalt in these sites cannot be reduced at 450 {sup o}C. The local environments about the rhenium atoms in Co-Re/{gamma}-A1{sub 2}O{sub 3} catalyst after different reduction periods have been studied by X-ray absorption spectroscopy. A bimetallic catalyst containing 4.6 wt% cobalt and 2 wt% rhenium has been compared with a corresponding monometallic sample with 2 wt% rhenium on the same support. The rhenium L{sub III} EXAFS analysis shows that bimetallic particles are formed after reduction at 450{sup o}C with the average particle size being 10-15 A. Rhenium is shown to be reduced at a later stage than cobalt. The fraction of cobalt atoms entering the support obstructs the access to the support for the

  5. Bimetallic Catalysts and Platinum Surfaces Studied by X-ray Absorption Spectroscopy and Scanning Tunnelling Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roenning, Magnus

    2000-07-01

    Bimetallic catalyst systems used in Fischer-Tropsch synthesis (Co-Re/Al{sub 2}O{sub 3}) and in the naphtha reforming process (Pt-Re/Al{sub 2}O{sub 3}) have been studied in situ using X-ray absorption spectroscopy (EXAFS). Additionally, the adsorption of ethene on platinum single crystal surfaces has been investigated using scanning tunnelling microscopy. In situ EXAFS at the cobalt K absorption edge have been carried out at 450{sup o}C on the hydrogen reduction of a rhenium-promoted Co{sub 3}O{sub 4}/Al{sub 2}O{sub 3} catalyst. Reductions carried out using 100% hydrogen and 5% hydrogen in helium gave different results. Whereas the reduction using dilute hydrogen leads to bulk-like metallic cobalt particles (hcp or fcc), reaction with pure hydrogen yields a more dispersed system with smaller cobalt metal particles (< 40 A). The results are rationalised in terms of different degrees of reoxidation of cobalt by the higher and lower concentrations of water generated during the reduction of cobalt oxide by 100% and 5% hydrogen, respectively. Additionally, in both reduction protocols a small fraction (3 -4 wt%) of the cobalt content is randomly dispersed over the tetrahedral vacancies of the alumina support. This dispersion occurs during reduction and not calcination. The cobalt in these sites cannot be reduced at 450 {sup o}C. The local environments about the rhenium atoms in Co-Re/{gamma}-A1{sub 2}O{sub 3} catalyst after different reduction periods have been studied by X-ray absorption spectroscopy. A bimetallic catalyst containing 4.6 wt% cobalt and 2 wt% rhenium has been compared with a corresponding monometallic sample with 2 wt% rhenium on the same support. The rhenium L{sub III} EXAFS analysis shows that bimetallic particles are formed after reduction at 450{sup o}C with the average particle size being 10-15 A. Rhenium is shown to be reduced at a later stage than cobalt. The fraction of cobalt atoms entering the support obstructs the access to the support for the

  6. Spectrophotometric determination of trace amounts of cadmium and lead with iodide and rhodamine B

    International Nuclear Information System (INIS)

    Highly sensitive spectrophotometric methods have been developed for determination of cadmium and lead, based on the CdI42- or PbI42- anionic complexes with Rhodamine B in the presence of polyvinyl alcohol to form ion-association complexes. The molar absorptivity is 4.2x105 l x mole-1 x cm-1 at 600 nm for cadmium and 5.7x105 l x mole-1 x cm-1 at 610 nm for lead. The complexes have the composition [CdI 42-] x [RhB+]2 and [PbI42-] x [RhB+]2 as established by Job's method of continuous variations and the molar-ratio method. The colour reaction selectivity is fairly good and the method can be applied for direct spectrophotometric determination of cadmium or lead in some pure metals. A species [PbI3-] x [RhB+] can also be formed, and extracted into toluene or a toluene/diethyl ether micture. (Authors)

  7. Alanine dosimetry using a spectrophotometric ferric-xylenol orange complex readout

    Energy Technology Data Exchange (ETDEWEB)

    Laere, K. van; Buysse, J.; Berkvens, P. (Ghent Rijksuniversiteit (Belgium). Lab. voor Kernfysica)

    1989-01-01

    The spectrophotometric dosimetric method using the indirect oxidation of ferrous ions after dissolution of irradiated DL-and L-alanine has been thoroughly investigated with respect to its composition, read-out procedure and dose-response. Optimal concentration of 0.10 N H{sub 2}SO{sub 4}, 0.2 mM xylenol orange and 0.2 mM Fe{sup 2+} were found, giving an absorption maximum at 547 nm. Standardization of chemical processing procedures allows a reproducibility better than 0.5%. The useful dose range has been extended to 0.03-12 kGy by means of slightly different read-out procedure. The quantitative concept of ''indirect yield'', G{sub id}, was introduced for this procedure as a measure of the indirect oxidation capacity of the radicals. It was found to be G{sub id,0}(Fe{sup 3+}) 7.1 ions/100 eV transferred into the alanine. The spectrophotometric readout combines the highly advantageous use of alanine as a dosemeter with the straightforwardness, accuracy and low costs of the chemical procedure. (author).

  8. Alanine dosimetry using a spectrophotometric ferric-xylenol orange complex readout

    International Nuclear Information System (INIS)

    The spectrophotometric dosimetric method using the indirect oxidation of ferrous ions after dissolution of irradiated DL-and L-alanine has been thoroughly investigated with respect to its composition, read-out procedure and dose-response. Optimal concentration of 0.10 N H2SO4, 0.2 mM xylenol orange and 0.2 mM Fe2+ were found, giving an absorption maximum at 547 nm. Standardization of chemical processing procedures allows a reproducibility better than 0.5%. The useful dose range has been extended to 0.03-12 kGy by means of slightly different read-out procedure. The quantitative concept of ''indirect yield'', Gid, was introduced for this procedure as a measure of the indirect oxidation capacity of the radicals. It was found to be Gid,0(Fe3+) 7.1 ions/100 eV transferred into the alanine. The spectrophotometric readout combines the highly advantageous use of alanine as a dosemeter with the straightforwardness, accuracy and low costs of the chemical procedure. (author)

  9. Effects of xylitol on carbohydrate digesting enzymes activity, intestinal glucose absorption and muscle glucose uptake: a multi-mode study.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

    2015-03-01

    The present study investigated the possible mechanism(s) behind the effects of xylitol on carbohydrate digesting enzymes activity, muscle glucose uptake and intestinal glucose absorption using in vitro, ex vivo and in vivo experimental models. The effects of increasing concentrations of xylitol (2.5%-40% or 164.31 mM-2628.99 mM) on alpha amylase and alpha glucosidase activity in vitro and intestinal glucose absorption and muscle glucose uptake were investigated under ex vivo conditions. Additionally, the effects of an oral bolus dose of xylitol (1 g per kg BW) on gastric emptying and intestinal glucose absorption and digesta transit in the different segments of the intestinal tract were investigated in normal and type 2 diabetic rats at 1 hour after dose administration, when phenol red was used as a recovery marker. Xylitol exhibited concentration-dependent inhibition of alpha amylase (IC₅₀ = 1364.04 mM) and alpha glucosidase (IC₅₀ = 1127.52 mM) activity in vitro and small intestinal glucose absorption under ex vivo condition. Xylitol also increased dose dependent muscle glucose uptake with and without insulin, although the uptake was not significantly affected by the addition of insulin. Oral single bolus dose of xylitol significantly delayed gastric emptying, inhibited intestinal glucose absorption but increased the intestinal digesta transit rate in both normal and diabetic rats compared to their respective controls. The data of this study suggest that xylitol reduces intestinal glucose absorption via inhibiting major carbohydrate digesting enzymes, slowing gastric emptying and fastening the intestinal transit rate, but increases muscle glucose uptake in normal and type 2 diabetic rats. PMID:25656339

  10. A systematic study on the absorption and fluorescence properties of 2,4,6-triaryl and tripyridylpyridines

    OpenAIRE

    FINDIK, Esra; ARIK, Mustafa; Ceylan, Mustafa

    2009-01-01

    Eight different 2,4,6-triaryl, and tripyridylpridines compounds were synthesized and their fluorescent properties were studied by using steady-state and time-resolved fluorescence and UV-Vis absorption spectroscopy techniques in 6 different solvents. Especially, 2,4,6-triarylpyridines showed strong fluorescence properties with high fluorescence quantum yields but small Stokes shifts.

  11. A general enhancement factor model for absorption and desorption systems: A CO2 capture case-study

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Fosbøl, Philip Loldrup

    2015-01-01

    This study derives a general method (GM) for reactive absorption and desorption calculation. It connects the Onda's approximation for reversible reactions with the van Krevelen's approach for instantaneous irreversible reactions. It is set-up for a reversible (m+n)-th order, forward reaction...

  12. Experimental and theoretical study of electronic structure of aluminum in extreme conditions with X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Matter in extreme conditions belongs to Warm Dense Matter regime which lays between dense plasma regime and condensed matter. This regime is still not well known, indeed it is very complex to generate such plasma in the laboratory to get experimental data and validate models. The goal of this thesis is to study electronic structure of aluminum in extreme conditions with X-ray absorption spectroscopy. Experimentally aluminum has reached high densities and high temperatures, up to now unexplored. An X-ray source has also been generated to probe highly compressed aluminum. Two spectrometers have recorded aluminum absorption spectra and aluminum density and temperature conditions have been deduced thanks to optical diagnostics. Experimental spectra have been compared to ab initio spectra, calculated in the same conditions. The theoretical goal was to validate the calculation method in high densities and high temperatures regime with the study of K-edge absorption modifications. We also used absorption spectra to study the metal-non metal transition which takes place at low density (density ≤ solid density). This transition could be study with electronic structure modifications of the system. (author)

  13. [Study on removing the lamp spectrum structure in differential optical absorption spectroscopy].

    Science.gov (United States)

    Qu, Xiao-ying; Li, Yu-jin

    2010-11-01

    Differential optical absorption spectroscopy (DOAS) technique has been used to measure trace gases in the atmosphere by their strongly structured absorption of radiation in the UV and visible spectral range, and nowadays this technique has been widely utilized to measure trace polluted gases in the atmosphere e.g. SO2, NO2, O3, HCHO, etc. However, there exists lamp (xenon lamp or deuteriumlamp) spectrum structure in the measured band (300-700 nm) of the absorption spectra of atmosphere, which badly impacts on precision of retrieving the concentration of trace gases in the atmosphere. People home and abroad generally employ two ways to handle this problem, one is segmenting band retrieving method, another is remedial retrieving method. In the present paper, a new retrieving method to deal with this trouble is introduced. The authors used moving-window average smoothing method to obtain the slow part of the absorption spectra of atmosphere, then achieved the lamp (xenon lamp in the paper) spectrum structure in the measured band of the absorption spectra of atmosphere. The authors analyzed and retrieved the measured spectrum of the atmosphere, and the result is better than the forenamed ways. Chi-square of residuum is 2.995 x 10(-4), and this method was proved to be able to avoid shortcoming of choosing narrowband and disadvantage of discovering the new component of atmosphere in retrieving the concentration of air pollutants and measuring the air pollutants. PMID:21284148

  14. LIQUID-LIQUID EXTRACTION AND SPECTROPHOTOMETRIC DETERMINATION OF IRON USING ACETOPHENONE 2’,5’-DIHYDROXY THIOSEMICARBAZONE (ADHTS AS A NEW ANALYTICAL REAGENT

    Directory of Open Access Journals (Sweden)

    Prabhakar S. Navarkar

    2012-09-01

    Full Text Available Acetophenone 2’,5’-dihydroxy thiosemicarbazone (ADHTS is proposed as a new sensitive and selective reagent for the Spectrophotometric determination of trace amount of Iron. The optimum extraction conditions were evaluated by studying various parameters like pH, solvent, reagent concentration, equilibration time and stability of extracted complex. The reagent reacts with Iron to form a yellow colored 1:2 chelate, at the pH 3.6.The complex is extracted in n-Butanol. The absorption spectrum shows maxima at 430 nm. Beer’s law is obeyed in the concentration range 1 to 8 ppm for Iron. The molar absorptivity is 646.06 L mol-1cm–1 and Sandell’s sensitivity is 0.0869μg cm-2 The Limit of Detection for the proposed method was found to be 0.561 ppm. The proposed method is highly sensitive, selective, simple, rapid, accurate, and has been satisfactorilyapplied for the determination of Iron in the synthetic mixtures, and real samples.

  15. Utilization of charge-transfer complexation in the spectrophotometric determination of some monosaccharides through their osazone intermediates.

    Science.gov (United States)

    Ayad, M; Belal, S; El Kheir, A A; El Adl, S

    1987-09-01

    Monosaccharide osazones are utilized in the spectrophotometric determination of their parent compounds though charge-transfer complexation with two-electron acceptor reagents. The molar combining ratio and the optimum complexation conditions have been studied. The method has been used to analyse for glucose and fructose and in determining blood glucose. PMID:18964408

  16. DEVELOPMENT AND VALIDATION OF FIRST ORDER DERIVATIVE SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS ESTIMATION OF PARACETAMOL AND TAPENTADOL HYDROCHLORIDE IN TABLET DOSAGE FORM

    OpenAIRE

    SAMIL D. DESAI*, BHAVNA A. PATEL, SHRADDHA J. PARMAR, NAITIK N. CHAMPANERI

    2013-01-01

    A simple, precise, accurate and reproducible spectrophotometric method has been developed forSimultaneous estimation of Paracetamol and Tapentadol Hydrochloride by employing first order derivativezero crossing method in 0.1 N Sodium Hydroxide. The first order derivative absorption at 257.1 nm (zerocross point of Paracetamol) was used for quantification of Tapentadol HCl and 289.0 nm (zero cross point ofTapentadol HCl) for quantification of Paracetamol. The linearity was established over the c...

  17. Development and validation of Ultra violet spectrophotometric and Reversed-phase High Performance Liquid Chromatography techniques for simultaneous estimation of Brinzolamide and Brimonidine tartrate in ophthalmic suspension formulation.

    OpenAIRE

    Gunasekar Manoharan; Mohammed Al Bratty

    2016-01-01

    A sensitive and fast UV spectrophotometric technique and feasible reverse phase liquid chromatographic method for the analysis of Brinzolamide and Brimonidine tartrate in ophthalmic formulation has been developed.Linearity ranges for both methods were 5 - 25 μg/ml and 1-5 μg/ml for brinzolamide and brimonidine tartrate respectively.The absorption maxima were observed at 232 and 257 nm for Brinzolamide and Brimonidine. The UV, ophthalmic formulation assay shows percentage purity ranging from 9...

  18. Determination of boron in niobium-zirconium alloys by distillation separation-curcumin spectrophotometric method

    International Nuclear Information System (INIS)

    Study was made on the distillation spearation-curcumin spectrophotometric method, which is used for the analysis of steel. In this method, a sample is dissolved in sulfuric acid and ammonium sulfate, and the solution is distilled by adding methanol to separate boron, and boron is colorized by curcumin for spectrophotometric determination. In the direct spectrophotometric determination of boron in Nb-Zr alloys by the methylene blue or curcumin method, the effect of coexistent elements such as Nb and Ta must be eliminated by means of dilution or separation with phytin. However, this method enables of determine boron in the distilled and separated solution with curcumin by stipulating a fixed amount of sulfuric acid and ammonium sulfate to be used for dissolving the sample, regardless of Nb and Ta contents, without any precipitation being formed. The recovery experiment using 2.5% Nb-Zr alloy and the analysis of in-house standard samples and JAERI-Z3 showed that this is a satisfactory analysis method. This procedure did not require any complex and skillful separating operation, and could shorten the analysis time in comparison with the phytin separation-methylene blue procedure. In addition, it can determine boron not less than 0.05 ppm, and is adequately applicable to the analysis with the specified value not more than 0.5 ppm for the advanced thermal reactor FUGEN. (Kobatake, H.)

  19. A surface extended X-ray absorption fine structure study of tellurium adsorbed onto Si(100)

    Science.gov (United States)

    Burgess, S. R.; Cowie, B. C. C.; Wilks, S. P.; Dunstan, P. R.; Dunscombe, C. J.; Williams, R. H.

    1996-09-01

    The adsorption of tellurium on Si(100) has been studied using surface extended X-ray adsorption fine structure (SEXAFS) and X-ray standing wave spectroscopy (XSW). This particular system is of interest due to its potential applicability in the surfactant aided growth of CdHgTeCdTeSi(100) based infra-red detectors. The Te/Si(100) structure was generated by depositing a thick layer (˜ 100 Å) of CdTe onto a clean Si (2 × 1) double domain surface, and annealing the sample to 350°C. This resulted is a ˜ 1 ML Te terminated surface where the (2 × 1) reconstruction was lost in favour of a (1 × 1) symmetry. X-ray absorption of the Te L 3 edge ( E = 4341 eV), with a photon energy range of 4440-4700 eV, was probed using a total yield detection scheme. The SEXAFS results indicated that the Te atoms sat in 2-fold bridge sites directly above a fourth layer Si atom. The corresponding bond length was measured to be 2.52 ± 0.05 Å. The XSW measurements of the (400) reflection gave a coherent position of 1.63 ± 0.03 Å and a coherent fraction of 0.65. This is consistent with the breaking of the SiSi dimers and thus could be an example of the phenomena of adsorbate-induced dereconstruction of the surface. These results are compared with those of Bennet et al. who examined a similar system using soft X-ray photoemission (SXPS) and the STM study of Yoshikawa et al.

  20. Molecular simulation and experimental study of CO2 absorption in ionic liquid reverse micelle.

    Science.gov (United States)

    Shi, Wei; Hong, Lei; Damodaran, Krishnan; Nulwala, Hunaid B; Luebke, David R

    2014-12-01

    The structure and dynamics for CO2 absorption in ionic liquid reverse micelle (ILRM) were studied using molecular simulations. The ILRM consisted of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) ionic liquid (IL) as the micelle core, the benzylhexadecyldimethylammonium ([BHD](+)) chloride ([Cl](-)) was the cationic surfactant, and benzene was used as the continuous solvent phase in this study. The diffusivity values of this ILRM system were also experimentally determined. Simulations indicate that there is ion exchange between the IL anion ([BF4](-)) and the surfactant anion ([Cl](-)). It was also found that the [bmim][BF4] IL exhibits small local density at the interface region between the IL core and the [BHD](+) surfactant cation layer, which leads to a smaller density for the [bmim][BF4] IL inside the reverse micelle (RM) compared with the neat IL. These simulation findings are consistent with experimental results. Both our simulations and experimental results show that [bmim][BF4] inside the RM diffuses 5-26 times faster than the neat IL, which is partly due to the fast particle diffusion for the ILRM nanodroplet (IL and surfactant) as a whole in benzene solvent compared with neat [bmim][BF4] diffusion. Additionally, it was found that [bmim][BF4] IL solved in benzene diffuses 2 orders of magnitude faster than the neat IL. Lastly, simulations show that CO2 molecules are absorbed in four different regions of the ILRM system, that is, (I) in the IL inner core, (II) in the [BHD](+) surfactant cation layer, (III) at the interface between the [BHD](+) surfactant cation layer and benzene solvent, and (IV) in the benzene solvent. The CO2 solubility was found to decrease in the order II > III ∼ IV > I, while the CO2 diffusivity and permeability decrease in the following order: IV > III > II > I. PMID:25382316

  1. Infrared absorption spectroscopic study of Nd3+ substituted Zn–Mg ferrites

    Indian Academy of Sciences (India)

    B P Ladgaonkar; C B Kolekar; A S Vaingankar

    2002-08-01

    Compositions of polycrystalline ZnMg1-Fe2–NdO4 ( = 0.00, 0.20, 0.40, 0.60, 0.80 and 1.00; = 0.00, 0.05 and 0.10) ferrites were prepared by standard ceramic method and characterized by X-ray diffraction, scanning electron microscopy and infrared absorption spectroscopy. Far infrared absorption spectra show two significant absorption bands, first at about 600 cm–1 and second at about 425 cm–1 , which were respectively attributed to tetrahedral (A) and octahedral (B) sites of the spinel. The positions of bands are found to be composition dependent. The force constants, $K_T$ and $K_O$, were calculated and plotted against zinc concentration. Compositional dependence of force constants is explained on the basis of cation–oxygen bond distances of respective sites and cation distribution.

  2. Three-photon absorption and vibrational spectroscopic study of 2-methylamino-5-chlorobenzophenone.

    Science.gov (United States)

    Sajan, D; Chaitanya, K; Safakath, K; Philip, Reji; Suthan, T; Rajesh, N P

    2013-04-01

    In this paper, the vibrational spectral analysis and three-photon absorption properties of an organic material of 2-methylamino-5-chlorobenzophenone have been reported. The geometry and harmonic vibrational wavenumbers are calculated with the help of B3LYP density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology (SQM). SQM force fields have also been used to calculate potential energy distribution (PED) in order to make conspicuous vibrational assignments. The nonlinear absorption properties have been investigated in ethanol solution at 532nm using the Z-scan technique employing laser pulses of 5ns duration. Open aperture Z-scan data reveal the presence of effective three-photon absorption for ns pulses at 532nm resulting in a strong optical limiting behavior, indicating possible photonic applications. PMID:23410921

  3. On Absorption by Circumstellar Dust, With the Progenitor of SN2012aw as a Case Study

    CERN Document Server

    Kochanek, C S; Dai, X

    2012-01-01

    We use the progenitor of SN2012aw to illustrate the consequences of modeling circumstellar dust using Galactic (interstellar) extinction laws that (1) ignore dust emission in the near-IR and beyond; (2) average over dust compositions, and (3) mis-characterize the optical/UV absorption by assuming that scattered photons are lost to the observer. The primary consequences for the progenitor of SN2012aw are that both the luminosity and the absorption are significantly over-estimated. In particular, the stellar luminosity is most likely in the range 10^4.8 0.3 micron) and total (absorption plus scattering) V-band optical depth (tau < 20). These do not include the contributions of dust emission, but provide a simple, physical alternative to incorrectly using interstellar extinction laws.

  4. Study on Sound Absorption Properties of Coconut Coir Fibre Reinforced Composite with Added Recycled Rubber

    Directory of Open Access Journals (Sweden)

    S. Mahzan

    2010-06-01

    Full Text Available Sound pollutions have become worsen and creating concerns for many peoples. Conventionally, expensive sound absorption materials are employed to control noise disturbances. However, recent developments on natural fibres have created interest for researchers especially for acoustics application purposes. This paper investigates the viability of coconut coir added with recycled rubber to be implemented as sound absorption panel. The composite is constructed at prescribed percentages of fillers and polyurethane as resin. The two-microphone method was applied to obtain the acoustic properties of the samples. The samples were also tested for physical properties such as density and porosity, as well as the microstructures. The results demonstrate good acoustics performances and highlight the potential of the coconut coir reinforced with recycled rubber as the sound absorption panel.

  5. STUDY ON EVOLUTION REGULARITIES AND ABSORPTION CHARACTERISTICS OF SULFIDE DURING BITUMINOUS BRIQUETTE HORIZONTAL COMBUSTION

    Institute of Scientific and Technical Information of China (English)

    路春美; 王永征

    1999-01-01

    This paper discusses the evolution regularity and the absorption characters of sulfide for bituminous briquette burned in a horizontal burning furnace. The evolution rate of sulphur is affected by some factors, such as the sulphur content in the burning coal, burning time and the meane excess air coefficient in the furnace. With processing the experimental result, the calculation related expression has been obtained to predict the evolution rate of sulfide. The sulphur absorption efficiency of briquette is affected by the factors such as the character of the sulphur sorbent, the type of the coal and the operating parameters. "By means of appropriately adjusting the calciumsulphur mole ratio, the mean excess air coefficient and the time-interval between pushing two layer briquettes, a high sulphur absorption efficiency (>74%) can be obtained.

  6. Spectrophotometric investigation of Phobos with the Rosetta OSIRIS-NAC camera and implications for its collisional capture

    Science.gov (United States)

    Pajola, M.; Lazzarin, M.; Bertini, I.; Marzari, F.; Turrini, D.; Magrin, S.; La Forgia, F.; Thomas, N.; Küppers, M.; Moissl, R.; Ferri, F.; Barbieri, C.; Rickman, H.; Sierks, H.

    2012-12-01

    The Martian satellite Phobos has been observed on 2007 February 24 and 25, during the pre- and post-Mars closest approach (CA) of the ESA Rosetta spacecraft Mars swing-by. The goal of the observations was the determination of the surface composition of different areas of Phobos, in order to obtain new clues regarding its nature and origin. Near-ultraviolet, visible and near-infrared (263.5-992.0 nm) images of Phobos's surface were acquired using the Narrow Angle Camera of the OSIRIS instrument onboard Rosetta. The six multi-wavelength sets of observations allowed a spectrophotometric characterization of different areas of the satellite, belonging respectively to the leading and trailing hemisphere of the anti-Mars hemisphere, and also of a section of its sub-Mars hemisphere. The pre-CA spectrophotometric data obtained with a phase angle of 19° have a spectral trend consistent within the error bars with those of unresolved/disc-integrated measurements present in the literature. In addition, we detect an absorption band centred at 950 nm, which is consistent with the presence of pyroxene. The post-CA observations cover from NUV to NIR a portion of the surface (0° to 43°E of longitude) never studied before. The reflectance measured on our data does not fit with the previous spectrophotometry above 650 nm. This difference can be due to two reasons. First, the OSIRIS observed area in this observation phase is completely different with respect to the other local specific spectra and hence the spectrum may be different. Secondly, due to the totally different observation geometry (the phase angle ranges from 137° to 140°), the differences of spectral slope can be due to phase reddening. The comparison of our reflectance spectra, both pre- and post-CA, with those of D-type asteroids shows that the spectra of Phobos are all redder than the mean D-type spectrum, but within the spectral dispersion of other D-types. To complement this result, we performed an investigation

  7. Analysis of Intra- and Intersubject Variability in Oral Drug Absorption in Human Bioequivalence Studies of 113 Generic Products.

    Science.gov (United States)

    Sugihara, Masahisa; Takeuchi, Susumu; Sugita, Masaru; Higaki, Kazutaka; Kataoka, Makoto; Yamashita, Shinji

    2015-12-01

    In this study, the data of 113 human bioequivalence (BE) studies of immediate release (IR) formulations of 74 active pharmaceutical ingredients (APIs) conducted at Sawai Pharmaceutical Co., Ltd., was analyzed to understand the factors affecting intra- and intersubject variabilities in oral drug absorption. The ANOVA CV (%) calculated from area under the time-concentration curve (AUC) in each BE study was used as an index of intrasubject variability (Vintra), and the relative standard deviation (%) in AUC was used as that of intersubject variability (Vinter). Although no significant correlation was observed between Vintra and Vinter of all drugs, Vintra of class 3 drugs was found to increase in association with a decrease in drug permeability (P(eff)). Since the absorption of class 3 drugs was rate-limited by the permeability, it was suggested that, for such drugs, the low P(eff) might be a risk factor to cause a large intrasubject variability. To consider the impact of poor water solubility on the variability in BE study, a parameter of P(eff)/Do (Do; dose number) was defined to discriminate the solubility-limited and dissolution-rate-limited absorption of class 2 drugs. It was found that the class 2 drugs with a solubility-limited absorption (P(eff)/Do class 1 drugs, effects of drug metabolizing enzymes were investigated. It was demonstrated that intrasubject variability was high for drugs metabolized by CYP3A4 while intersubject variability was high for drugs metabolized by CYP2D6. For CYP3A4 substrate drugs, the Km value showed the significant relation with Vintra, indicating that the affinity to the enzyme can be a parameter to predict the risk of high intrasubject variability. In conclusion, by analyzing the in house data of human BE study, low permeability, solubility-limited absorption, and high affinity to CYP3A4 are identified as risk factors for high intrasubject variability in oral drug absorption. This information is of importance to design the human BE

  8. Inclusion of riboflavin in β-cyclodextrin: A fluorimetric and absorption spectrometric study

    Science.gov (United States)

    Roy, Dalim Kumar; Deb, Nipamanjari; Ghosh, Bankim Chandra; Mukherjee, Asok K.

    2009-07-01

    Formation of inclusion complexes between riboflavin and β-cyclodextrin (β-CD) with both 1:1 and 1:2 stoichiometry has been established by fluorimetric titration. However, in absorption spectrometric experiment, spectral change of riboflavin in the visible range could be observed only by taking β-CD at a much higher concentration (about 100 times) than riboflavin and under such condition only 1:2 complexes could be detected. Its formation constant ( K) was determined by a multiple linear regression analysis of the absorption data. The reliability of the K value was confirmed by the consistency achieved on analyzing the data at two different wavelengths.

  9. Theoretical Study on Absorption of Magnetically Tunable Terahertz Quantum- Well Photodetectors

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-Ling; GUO Xu-Guang; CAO Jun-Cheng

    2006-01-01

    Because of the Zeeman splitting effect in diluted semiconductor (Zn,Cd,Mn)Se, the absorption spectrum of ZnSe/(Zn,Cd,Mn)Se quantum wells can be adjusted by magnetic field effectively. Within the effective-mass approximation, the conduction electronic structure and the absorption spectrum of ZnSe/(Zn,Cd,Mn)Se quantum wells subjected to in-plane magnetic Gelds are investigated. Our theoretical results show that it is possible to use the ZnSe/(Zn,Cd,Mn)Se quantum well as magnetically tunable terahertz photodetectors.

  10. Studies on absorption and translocation of phosphorus using radioactive superphosphate (32P) in coffee plants

    International Nuclear Information System (INIS)

    Absorption and translocation (downward as well as lateral) of phosphate ions from foliar applied superphosphate solution (pH 6.5, labelled with 32P) were considerably higher in Coffea arabica L. cv.S. 795 than in Coffea canephera Pierre cv.S. 274 plants. The differential absorption and translocation of phosphate to various plant parts and its accumulation in enlarged flowers buds suggest the possibility that the requirement of phosphorus for flower bud enlargement and blossom (anthesis) is higher in arabica than in robusta. (auth.)

  11. A Relative Study on Two-photon Absorption Properties of C60 and C70

    Institute of Scientific and Technical Information of China (English)

    ZHOU,Xin(周新); REN,Ai-Min(任爱民); FENG,Ji-Kang(封继康); LIU,Xiao-Juan(刘孝娟)

    2004-01-01

    We have theoretically investigated the one- and two-photon absorption properties of C60 and C70 using the ZINDO method. From the results it is suggested that the one-photon absorption spectra are in agreement with the experimental observations. It is found that the maximum TPA cross section of C70 is more than twice that of C60,which is consistent with the experimental results. A notable point is that the TPA process of C60 is different from that of C70 as well as other ordinary conjugated molecules.

  12. Selective and non-extractive spectrophotometric determination of cefdinir in formulations based on donor-acceptor complex formation

    Directory of Open Access Journals (Sweden)

    Babita K. Singh

    2010-01-01

    Full Text Available Cefdinir has broad spectrum of activity and high prescription rates, hence its counterfeiting seems imminent. We have proposed a simple, fast, selective and non-extractive spectrophotometric method for the content assay of cefdinir in formulations. The method is based on complexation of cefdinir and Fe under reducing condition in a buffered medium (pH 11 to form a magenta colored donor-acceptor complex (λ max = 550 nm; apparent molar absorptivity = 3720 L mol-1 cm-1. No other cephalosporins, penicillins and common excipients interfere under the test conditions. The Beer's law is followed in the concentration range 8-160 µg mL-1.

  13. Experimental Studies of the Mechanism of Photon Absorption on Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Steven Morrow

    2000-09-13

    A measurement of the reaction {sup 12}C({gamma},p{gamma}{prime}) has been made with tagged photons in the range 49.47 < E{sub {gamma}} < 70.24 MeV. The relative population of a triplet of states, (7/2{sup -}, 1/2{sup +}, 5/2{sup +}) at E{sub ex} {approx_equal} 7 MeV in the residual nucleus {sup 11}B, following the reaction {sup 12}C({gamma},p), has been made by directly resolving their de-excitation {gamma}-ray decay to the ground state of {sup 11}B. This measurement constitutes the highest resolution ever achieved in determining the excitation function of the residual nucleus after a ({gamma},p) reaction ({approx} 48 keV FWHM at E{sub ex} {approx_equal} 7 MeV). Comparison has been made with the data of Kuzin et al, who also measured the relative populations with a resolution of {approx} 270 keV at E{sub ex} {approx_equal} 7 MeV. The 7/2{sup -} state at 6.74 MeV has been observed to be the most strongly excited state of the triplet in agreement with Kuzin et al. Disagreement has been found for the relative strengths of the 1/2{sup +} and 5/2{sup +} states in the triplet. An estimation of the maximum effect of angular correlations between the ejected proton and de-excitation {gamma}-ray has been included in the analysis. This effect increases the disagreement between the measurements. A study of the reaction {sup 12}C(e,e{prime}p) has been made in the missing momentum region 260 < p{sub m} < 320 MeV/c. A Rosenbluth separation of the reaction cross section has been carried out in parallel kinematics to measure the structure functions W{sub L} and W{sub T}. The experimental data have been compared with Complete Distorted Wave Impulse Approximation calculations and Random Phase Approximation calculations. The latter when including virtual photon absorption on 2-body currents (Meson Exchange Currents + Isobar Currents) are seen to describe the reduced cross sections better than 1-body current or Complete Distorted Wave Impulse Approximation calculations. For the 1st

  14. Spectrophotometric Determination of Cu2+ and Monitoring of Hg2+ and Ni2+ in some Iranian Vegetables Using 6-(2-Naphthyl)-2, 3-Dihydro-as-triazine-3-thione

    Science.gov (United States)

    Shamsa, Fazel; Barazande Tehrani, Malehe; Mehravar, Hamid; Mohammadi, Elaheh

    2013-01-01

    Recently, 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione (NDTT) was synthesized in laboratory and used successfully for the spectrophotometric determination of nanogram levels of Cu2+ in aqueous solution. This reagent forms a specific red complex with Cu2+ ions after the extraction by chloroform at alkaline pH. The absorption of the complex in the UV region (313 nm) is about 8 times as strong as in the visible one (510 nm). Mercury and nickel ions form yellow complexes with NDTT under the same conditions which interfere in the UV region and without effect on Cu (II) absorbance in the visible region. The studied vegetables include Mentha pipereta L., Anethum graveolens L., Beta vulgaris L., Coriandrum sativum, Petroselinum hortense H., Ocimum basilicum L., Spinacia oleracea L., Lactuca sativa L., and Brassica oleracea L. PMID:24250566

  15. Spectrophotometric Determination of Cu(2+) and Monitoring of Hg(2+) and Ni(2+) in some Iranian Vegetables Using 6-(2-Naphthyl)-2, 3-Dihydro-as-triazine-3-thione.

    Science.gov (United States)

    Shamsa, Fazel; Barazande Tehrani, Malehe; Mehravar, Hamid; Mohammadi, Elaheh

    2013-01-01

    Recently, 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione (NDTT) was synthesized in laboratory and used successfully for the spectrophotometric determination of nanogram levels of Cu(2+) in aqueous solution. This reagent forms a specific red complex with Cu(2+) ions after the extraction by chloroform at alkaline pH. The absorption of the complex in the UV region (313 nm) is about 8 times as strong as in the visible one (510 nm). Mercury and nickel ions form yellow complexes with NDTT under the same conditions which interfere in the UV region and without effect on Cu (II) absorbance in the visible region. The studied vegetables include Mentha pipereta L., Anethum graveolens L., Beta vulgaris L., Coriandrum sativum, Petroselinum hortense H., Ocimum basilicum L., Spinacia oleracea L., Lactuca sativa L., and Brassica oleracea L. PMID:24250566

  16. Tropospheric aerosol scattering and absorption over Central Europe: a closure study for the dry particle state

    Directory of Open Access Journals (Sweden)

    N. Ma

    2013-10-01

    Full Text Available This work analyses optical properties of the dry tropospheric aerosol measured at the regional GAW observation site Melpitz in East Germany. For a continuous observation period between 2007 and 2010, we provide representative values of the dry-state scattering coefficient, the hemispheric backscattering coefficient, the absorption coefficient, single scattering albedo, and the Ångström exponent. Besides the direct measurement, the aerosol scattering coefficient was alternatively computed from experimental particle number size distributions using a Mie code. Within pre-defined limits, a closure could be achieved with the direct measurement. The achievement of closure implies that such calculations can be used as a high-level quality control measure for data sets involving multiple instrumentation. All dry optical properties showed significant annual variations, which were attributed to corresponding variations in the regional emission fluxes, the intensity of secondary particle formation, and the mixed layer height. Air mass classification showed that atmospheric stability is a major factor influencing the dry aerosol properties at the GAW station. In the cold season, temperature inversions limit the volume available for atmospheric mixing, so that the aerosol optical properties near the ground proved quite sensitive to the geographical origin of the air mass. In the warm season, when the atmosphere is usually well-mixed during day-time, considerably less variability was observed for the optical properties between different air masses. This work provides, on the basis of quality-checked in-situ measurements, a first step towards a climatological assessment of direct aerosol radiative forcing in the region under study.

  17. Feasibility Study of Multi-Wavelength Differential Absorption LIDAR for CO2 Monitoring

    Directory of Open Access Journals (Sweden)

    Chengzhi Xiang

    2016-06-01

    Full Text Available To obtain a better understanding of carbon cycle and accurate climate prediction models, highly accurate and temporal resolution observation of atmospheric CO2 is necessary. Differential absorption LIDAR (DIAL remote sensing is a promising technology to detect atmospheric CO2. However, the traditional DIAL system is the dual-wavelength DIAL (DW-DIAL, which has strict requirements for wavelength accuracy and stability. Moreover, for on-line and off-line wavelengths, the system’s optical efficiency and the change of atmospheric parameters are assumed to be the same in the DW-DIAL system. This assumption inevitably produces measurement errors, especially under rapid aerosol changes. In this study, a multi-wavelength DIAL (MW-DIAL is proposed to map atmospheric CO2 concentration. The MW-DIAL conducts inversion with one on-line and multiple off-line wavelengths. Multiple concentrations of CO2 are then obtained through difference processing between the single on-line and each of the off-line wavelengths. In addition, the least square method is adopted to optimize inversion results. Consequently, the inversion concentration of CO2 in the MW-DIAL system is found to be the weighted average of the multiple concentrations. Simulation analysis and laboratory experiments were conducted to evaluate the inversion precision of MW-DIAL. For comparison, traditional DW-DIAL simulations were also conducted. Simulation analysis demonstrated that, given the drifting wavelengths of the laser, the detection accuracy of CO2 when using MW-DIAL is higher than that when using DW-DIAL, especially when the drift is large. A laboratory experiment was also performed to verify the simulation analysis.

  18. A comparative study on the GAX based absorption refrigeration systems: SGAX, GAXH and GAX-E

    International Nuclear Information System (INIS)

    In this paper, two GAX-ejector absorption refrigeration cycles are proposed and investigated thermodynamically. In the first cycle (GAX-E Model A), the ejector draws vapor from the evaporator and raises the absorber pressure. In the second combined cycle (GAX-E Model B), the ejector is used to raise the condenser pressure. The performances of these two cycles are compared with those of the standard GAX (SGAX) cycle and two different arrangements of the hybrid GAX (GAXH Model A and GAXH Model B) cycles at the same working conditions. The comparison is performed through parametric studies in which the effects of generator and evaporator temperatures as well as the degassing range on the first and second law efficiencies are investigated. It is found that the COP of GAX-E Model B cycle is higher than that of the SGAX cycle by up to 16.7%. The maximum second law efficiency for the GAX-E Model B cycle is only slightly lower than the highest efficiency value which is obtained for the GAXH Model B cycle. As there is no compressor in the GAX-E Model B cycle, this cycle can be recommended for refrigeration purposes from the viewpoint of thermo-economics. - Highlights: ► Five different configurations of GAX based cycles are compared thermodynamically. ► For all the GAX cycles the highest exergy destructions occur in the absorber–desorber. ► The COP of standard GAX cycle is enhanced by 16.7% when an ejector is employed.

  19. Synchrotron soft X-ray absorption spectroscopy study of carbon and silicon nanostructures for energy applications.

    Science.gov (United States)

    Zhong, Jun; Zhang, Hui; Sun, Xuhui; Lee, Shuit-Tong

    2014-12-10

    Carbon and silicon materials are two of the most important materials involved in the history of the science and technology development. In the last two decades, C and Si nanoscale materials, e.g., carbon nanotubes, graphene, and silicon nanowires, and quantum dots, have also emerged as the most interesting nanomaterials in nanoscience and nanotechnology for their myriad promising applications such as for electronics, sensors, biotechnology, etc. In particular, carbon and silicon nanostructures are being utilized in energy-related applications such as catalysis, batteries, solar cells, etc., with significant advances. Understanding of the nature of surface and electronic structures of nanostructures plays a key role in the development and improvement of energy conversion and storage nanosystems. Synchrotron soft X-ray absorption spectroscopy (XAS) and related techniques, such as X-ray emission spectroscopy (XES) and scanning transmission X-ray microscopy (STXM), show unique capability in revealing the surface and electronic structures of C and Si nanomaterials. In this review, XAS is demonstrated as a powerful technique for probing chemical bonding, the electronic structure, and the surface chemistry of carbon and silicon nanomaterials, which can greatly enhance the fundamental understanding and also applicability of these nanomaterials in energy applications. The focus is on the unique advantages of XAS as a complementary tool to conventional microscopy and spectroscopy for effectively providing chemical and structural information about carbon and silicon nanostructures. The employment of XAS for in situ, real-time study of property evolution of C and Si nanostructures to elucidate the mechanisms in energy conversion or storage processes is also discussed.

  20. Comparative characterisation study of a LaBr$_3$(Ce scintillation crystal in two surface wrapping scenarios: absorptive and reflective

    Directory of Open Access Journals (Sweden)

    Saad eAldawood

    2015-12-01

    Full Text Available The properties of a 50$times$50$times$30 mm$^3$ monolithic LaBr$_3$:Ce scintillator crystal coupled to a position-sensitive multi-anode photomultiplier (PMT, Hamamatsu H9500, representing the absorbing detector of a Compton camera under study for online ion (proton beam range verification in hadron-therapy, was evaluated in combination with either absorptive and reflective crystal surface coating. This study covered an assessment of the energy and position dependent energy resolution, exhibiting a factor of 2.5-3.5 improvement for the reflectively wrapped crystal at 662 keV. The spatial dependency was investigated using a collimated $^{137}$Cs source, showing a steep degradation of the energy resolution at the edges and corners of the absorptively wrapped crystal. Furthermore, the time resolution was determined to be 273 ps (FWHM and 536 ps (FWHM with reflective and absorptive coating, respectively, using a $^{60}$Co source. In contrast, the light spread function (LSF of the light amplitude distribution on the PMT segments improved for the absorptively wrapped detector. Both wrapping modalities showed almost no differences in the energy-dependent photopeak detection efficiency.

  1. Variability of calcium absorption

    International Nuclear Information System (INIS)

    Variability in calcium absorption was estimated in three groups of normal subjects in whom Ca absorption was measured by standard isotopic-tracer methods at interstudy intervals ranging from 1 to 4 mo. Fifty absorption tests were performed in 22 subjects. Each was done in the morning after an overnight fast with an identical standard breakfast containing a Ca load of approximately 250 mg. Individual fractional absorption values were normalized to permit pooling of the data. The coefficient of variation (CVs) for absorption for the three groups ranged from 10.57 to 12.79% with the size of the CV increasing with interstudy duration. One other published study presenting replicate absorption values was analyzed in a similar fashion and was found to have a CV of absorption of 9.78%. From these data we estimate that when the standard double-isotope method is used to measure Ca absorption there is approximately 10% variability around any given absorption value within an individual human subject and that roughly two-thirds of this represents real biological variability in absorption

  2. Optical absorption and X-ray photoelectron spectroscopic studies of thorium tetrabromide

    International Nuclear Information System (INIS)

    Optical absorption and X-ray photoelectron spectroscopies have been used to investigate the electronic structure of ThBr4 in relation to ThF4 and ThCl4. The same electronic process appears to be responsible for the Th 4f photoelectron 'shake-up' satellites and the valence to conduction band transition. (author)

  3. A multivariant study of the absorption properties of poly(glutaric-acid-glycerol) films

    Science.gov (United States)

    The solvent absorption into the matrix of poly(glutaric acid-glycerol) films made with or without either iminodiacetic acid, sugarcane bagasse, pectin, corn fiber gum or microcrystalline cellulose have been evaluated. The films were incubated in various solvent systems for 24h. The amounts of solve...

  4. X-ray Emission and Absorption Studies of Silicides in Relation to their Electronic Structure

    NARCIS (Netherlands)

    Weijs, P.J.W.; Wiech, G.; Zahorowski, W.; Speier, W.; Goedkoop, J.B.; Czyzyk, Marek; Acker, J.F. van; Leuken, E. van; Groot, R.A. de; Laan, G. van der; Sarma, D.D.; Kumar, L.; Buschow, K.H.J.; Fuggle, J.C.

    1990-01-01

    The valence bands and conduction bands of about 30 transition metal silicides (of which we concentrate on 4 here) have been investigated by measurements of Si X-ray emission bandsspectra, X-ray absorption spectra near the Si K (1s) edge, photoemission spectra, and Bremsstrahlung Isochromat spectra.

  5. Absorption of magnesium in intestinal loop studied by the multitracer technique

    International Nuclear Information System (INIS)

    We investigated Mg absorption in the intestine, and pregnancy-associated changes in Mg absorption by the rat everted gut sac method. Heavy ion beam accelerated by ring-cyclotron was irradiated to a titanium target and the radioactive multitracer solution which includes 28Mg was made. 9 weeks old female Wistar rats (non-pregnancy, 6∼20th day of the pregnancy) were fasted overnight and anesthetized. Four segments of the intestine were isolated and everted to prepare sac specimens with mucosa outside. Each specimen was filled with multitracer solution and was immersed in the same solution. After incubation the multitracer solutions in both of inside and outside the sacs were removed. The radioactivity of the each sample was determined by gamma-ray spectrometry. In non-pregnant state, the active transport of Mg from mucosal side into serosal side exists only in colon. This active transport of Mg in colon during pregnancy was significantly decreased than in non-pregnant state. The mechanism and importance of the decrease in Mg absorption during pregnancy are still unclear. In humans, the intracellular and extracellular Mg concentrations decrease with the normal pregnancy course, especially in preeclampsia. The association between the changes in active Mg absorption during pregnancy and the pathogenesis should be clarified as early as possible. (author)

  6. Generation dependent singlet–singlet annihilation within multichromophoric dendrimers studied by polychromatic transient absorption

    NARCIS (Netherlands)

    Jordens, Sven; Belder, Gino De; Lor, Marc; Schweitzer, Gerd; Auweraer, Mark Van der; Weil, Tanja; Herrmann, Andreas; Wiesler, Uwe-M.; Müllen, Klaus; Schryver, Frans C. De

    2003-01-01

    Intramolecular kinetic processes in a series of shape-persistent meta- and para-substituted polyphenylene dendrimers bearing different peryleneimide chromophores at the rim have been investigated using time-resolved polychromatic transient absorption measurements. The influence of the generation num

  7. Magnetic field dependent microwave absorption studies on a MgB{sub 2} superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Bhide, M.K.; Kadam, R.M.; Sastry, M.D. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Singh, Ajay; Sen, Shashwati; Aswal, D.K.; Sahni, V.C.; Gupta, S.K. [Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)]. E-mail: drgupta@magnum.barc.ernet.in

    2001-08-01

    Polycrystalline MgB{sub 2}, synthesized using a conventional solid-state reaction route, has been investigated for its magnetic field dependent microwave absorption using a standard X-band EPR spectrometer. The changes in microwave absorption as a function of temperature and/or magnetic field were recorded by following the microwave reflectivity of a sample-loaded cavity. The modulated low-field microwave absorption signal was found to be similar to that observed in high-temperature superconducting materials. The field dependent direct microwave absorption in the 0-10 kG range was used to determine H{sub c1} values at different temperatures, and the value of H{sub c1}(0) was found to be 250 G. The absorbed microwave power has been found to obey a (H){sup 1/2} dependence with a change of slope indicating a transition from a strongly pinned flux lattice to the flux flow regime. (author)

  8. Photoelectron, nuclear gamma-ray and infrared absorption spectroscopic studies of neptunium in sodium silicate glass

    International Nuclear Information System (INIS)

    The valence state of neptunium ions in sodium silicate glasses prepared under reducing and oxidizing conditions has been investigated by the x-ray photoelectron, Moessbauer and optical absorption spectroscopic techniques. Results indicate that the Np ions are tetravalent in glasses prepared under reducing conditions and pentavalent in glasses prepared under oxidizing conditions

  9. VUV Fourier-transform absorption study of the Lyman and Werner bands in D-2

    NARCIS (Netherlands)

    Lange, de A.; Dickenson, G.D.; Salumbides, E.J.; Ubachs, W.M.G.; Oliveira, de N.; Joyeux, D.; Nahon, L.

    2012-01-01

    An extensive survey of the D-2 absorption spectrum has been performed with the high-resolution VUV Fourier-transform spectrometer employing synchrotron radiation. The frequency range of 90 000-119 000 cm (1) covers the full depth of the potential wells of the B (1)Sigma(+)(u), B' 1 Sigma(+)(u), and

  10. Oxidation of plutonium dioxide: an X-ray absorption spectroscopy study

    International Nuclear Information System (INIS)

    X-ray absorption spectroscopy experiments were conducted in order to characterise plutonium dioxide oxidation. It is shown that the sample preparation adopted does not enable elaboration of hyperstoichiometric plutonium dioxide. These results could mean that plutonium dioxide oxidation only occurs under very specific conditions

  11. Quantum theory and experimental studies of absorption spectra and photoisomerization of azobenzene polymers

    DEFF Research Database (Denmark)

    Pedersen, Thomas Garm; Ramanujam, P.S.; Johansen, P.M.;

    1998-01-01

    The microscopic properties of azobenzene chromophores are important for a correct description of optical storage systems based on photoinduced anisotropy in azobenzene polymers. A quantum model of these properties is presented and verified by comparison to experimental absorption spectra for tran...

  12. Selective spectrophotometric determination of phenolic beta-lactam antibiotics.

    Science.gov (United States)

    Salem, Hesham; Saleh, Gamal A

    2002-06-15

    Two simple and selective spectrophotometric methods were developed for the quantitative determination of cefoperazone sodium, cefadroxil monohydrate, cefprozil anhydrous and amoxicillin trihydrate in pure forms as well as in their pharmaceutical formulations. The methods are based on the selective oxidation of these drugs with either Ce (IV) or Fe (III) in acid medium to give an intense yellow coloured product (lambda(max)=397 nm). The reaction conditions were studied and optimized. Beer's plots were obeyed in a general concentration range of 5-30 microg ml(-1) with correlation coefficients not less than 0.9979 for the four drugs with the two reagents. The methods are successfully applied to the analysis of pharmaceutical formulations containing amoxicillin, either alone or in combination with potassium clavulanate, flucloxacillin or dicloxacillin. They were also applied to the analysis of the other three studied drugs in vials, capsules, tablets and suspensions with good recovery; percent ranged from 99.7 (+/-0.46) to 100.32 (+/-1.05) in the Ce (IV) method and 99.6 (+/-0.50) to 100.3 (+/-1.32) in the Fe (III) method. Interferences from other antibiotics and additives products were investigated.

  13. Spectrophotometric determination of micro quantities of zinc in rocks

    Science.gov (United States)

    Huffman, C.; Lipp, H.H.; Rader, L.F.

    1963-01-01

    A chemical method is presented for the determination of microgram amounts of zinc in rocks. Zinc is absorbed on anion-exchange resin from 1.2 M hydrochloric acid and eluted with 0.01 M hydrochloric acid. A diethyldithiocarbamate separation removes traces of interfering elements from the eluate. The zinc-diethyldithiocarbamate complex is extracted into chloroform at pH 8.5 and reextracted from other elements in the chloroform solution with 0.16 M hydrochloric acid and finally determined spectrophotometrically as the zincon complex at 621 m??. The coefficient of variation of the method determined from replicate determinations of zinc on 75 selected samples of basalt, ranging in zinc content from 0.004 to 0.018 per cent, was found to be 6.3 per cent and essentially constant in the range of zinc content studied. This method of analysis has been used extensively for a study of zinc in basalts reported by Rader, Swadley, Huffman and Lipp (companion paper, 1963). ?? 1963.

  14. A spectrophotometric method for the determination of Hydrogen Sulphide sugar cane juice and water

    International Nuclear Information System (INIS)

    A sensitive spectrophotometric is developed for the determination of hydrogen sulphide in water and sugarcane juice. The method is based on the reaction of hydrogen sulphide with phospomolybdate (ammonium molybdate and phosphate) in sulphuric acid medium. The system obeys Lambert-Beer's law at 715 nm in the concentration range of 0.284-5.68 ug ml. Molar absorptivity, correlation coefficient and Sandell sensitivity values were found to be 5x10 l mol cm, 0.9995 and 0.0494 ug cm respectively. The method was employed for the determination of hydrogen sulphide in sugar cane juice and in water samples. The results obtained were reproducible with acceptable standard deviation 0.1140-0.1337 and relative standard deviation varies from 0.0797-0.6038%. For comparison, hydrogen sulphide present in sugarcane juice and water samples were also determined separately following the methylene blue official method. The results of the proposed method compare well with the official method. (author)

  15. Determination of ametryn in sugarcane and ametryn-atrazine herbicide formulations using spectrophotometric method.

    Science.gov (United States)

    Shah, Jasmin; Jan, M Rasul; Ara, Behisht; Shehzad, Farhat-Un-Nisa

    2012-06-01

    A sensitive spectrophotometric method has been developed for determination of ametryn in agricultural samples. The proposed method was based on reaction with pyridine and further coupling with sulfanilic acid to form a colored product. The absorbance was measured at 400 nm with a molar absorptivity of 2.1 x 10(5) L mol(-1) cm(-1). The method shows a linear range from 0.2-20 μg mL(-1) with limit of detection and limit of quantification 0.16 and 0.54 μg mL(-1), respectively. The method has been successfully applied to the determination of ametryn in sugarcane juice and commercial formulations after separation of ametryn from triazine herbicides based on solvent extraction. Recovery values were found to be in the range of 96.0 ± 0.2% to 98.4  ±  0.1%.

  16. Spectrophotometric determination of ajmaline and brucine by Folin Ciocalteu’s reagent

    Directory of Open Access Journals (Sweden)

    ARCHANA SAHU

    2003-09-01

    Full Text Available A rapid and simple spectrophotometric procedure is described for the determination of ajmaline and brucine. The method is based on the development of blue coloured product due to reduction of tungstate and/or molybdate in Folin Ciocalteu’s reagent (FCR by ajmaline and brucine in alkaline medium. The colour is stable for more than 48 h. The chromogenic reaction has lmax at 540 nm with molar absorptivity 1.64×104 and 2.37×103 l mol-1 cm-1 in the Beer’s law range 1–8 mg ml-1 and 10–100 mg ml-1 for ajmaline and brucine, respectively.

  17. Alanine in high-dose dosimetry: spectrophotometric and electrochemical readout procedures compared with ESR

    Energy Technology Data Exchange (ETDEWEB)

    Van Laere, K.; Buysse, J.; Berkvens, P. (Ghent Rijksuniversiteit (Belgium). Lab. voor Kernfysica)

    1989-01-01

    The ESR readout of radical concentrations produced upon irradiation of {alpha}-alanine is compared and related to other physico-chemical detection methods. Dissolution of the free radicals in an acid ferrous sulphate solution leads to an indirect oxidation of ferrous ions. After complex formation with the dye xylenol orange optical absorption measurements can be made within a dose range from 0.03 to 12 kGy. The yield of ammonia, produced upon dissolution in a basic aqueous solution, provides spectrophotometric evaluations after complex formation with a mercury iodide containing reagent for the dose range 5 kGy to 1 MGy. A practical new routine dosimeter for applications in the range 300 Gy to at least 1 MGy, by means of an ion-selective ammonia electrode, is proposed. (author).

  18. Spectrophotometric method for Simultaneous estimation of Atorvastatin Calcium & Fenofibrate in tablet Dosage Form

    Directory of Open Access Journals (Sweden)

    Hirave Rupali. V

    2013-03-01

    Full Text Available A UV spectrophotometric method was developed for the estimation of atorvastatin calcium & fenofibrate in tablet dosage form by using simultaneous equation method. The drug obeyed Beer’s law & showed good correlation near to 0.999. Absorption maxima of atorvastatin calcium & fenofibrate were found to be at 246 and 286 nm respectively. Beer’s law was obeyed in concentration rang of 1-10 μg/ml for atorvastatin calcium & 2-20 μg/ml for fenofibrate. The method has been validated for linearity, accuracy & precision. The recovery was more than 99%. The developed method was found to be accurate, simple, precise, economical, and selective for simultaneous estimation of atorvastatin calcium & fenofibrate in tablet dosage form.

  19. Reverse saturable absorption studies in polymerized indole - Effect of polymerization in the phenomenal enhancement of third order optical nonlinearity

    Science.gov (United States)

    Jayakrishnan, K.; Joseph, Antony; Bhattathiripad, Jayakrishnan; Ramesan, M. T.; Chandrasekharan, K.; Siji Narendran, N. K.

    2016-04-01

    We report our results on the identification of large order enhancement in nonlinear optical coefficients of polymerized indole and its comparative study with reference to its monomer counterpart. Indole monomer shows virtually little third order effects whereas its polymerized version exhibits phenomenal increase in its third order nonlinear optical parameters such as nonlinear refractive index and nonlinear absorption. Open aperture Z-scan trace of polyindole done with Q-switched Nd:YAG laser source (532 nm, 7 ns), shows β value as high as 89 cm/GW at a beam energy of 0.83 GW/cm2. Closed aperture Z-scan done at identical energies reveals nonlinear refractive index of the order of -3.55 × 10-17 m2/W. Band gap measurement of polyindole was done with UV-Vis absorption spectra and compared with that of Indole. FTIR spectra of the monomer and polymerized versions were recorded and relevant bond formations were confirmed from the characteristic peaks. Photo luminescent spectra were investigated to know the emission features of both molecules. Beam energy (I0) versus nonlinear absorption coefficient (β) plot indicates reverse saturable type of absorption behaviour in polyindole molecules. Degenerate Four Wave Mixing (DFWM) plot of polyindole reveals quite a cubic dependence between probe and phase conjugate signal and the resulting χ(3) is comparable with Z-scan results. Optical limiting efficiency of polyindole is comparable with certain derivatives of porphyrins, phthalocyanines and graphene oxides.

  20. Study of nonlinear optical absorption properties of Sb2Se3 nanoparticles in the nanosecond and femtosecond excitation regime

    Science.gov (United States)

    Molli, Muralikrishna; Pradhan, Prabin; Dutta, Devarun; Jayaraman, Aditya; Bhat Kademane, Abhijit; Muthukumar, V. Sai; Kamisetti, Venkataramaniah; Philip, Reji

    2016-05-01

    In this work, we report for the first time, the nonlinear optical absorption properties of antimony selenide (Sb2Se3) nanoparticles synthesized through solvothermal route. X-ray diffraction results revealed the crystalline nature of the nanoparticles. Electron microscopy studies revealed that the nanoparticles are in the range of 10-40 nm. Elemental analysis was performed using EDAX. The nanosecond optical limiting effect was characterized by using fluence-dependent transmittance measurements with 15-ns laser pulses at 532 and 1064 nm excitation wavelengths. Mechanistically, effective two-photon (2PA) absorption and nonlinear scattering processes were the dominant nonlinear processes at both the wavelengths. At 800 nm excitation in the femtosecond regime (100 fs), the nonlinear optical absorption was found to be a three-photon (3PA) process. Both 2PA and 3PA processes were explained using the band structure and density of states of Sb2Se3 obtained using density functional theory. These nanoparticles exhibit strong intensity-dependent nonlinear optical absorption and hence could be considered to have optical power-limiting applications in the visible range.

  1. New Spectrophotometric Assay of Pyrantel Pamoate in Pharmaceuticals and Spiked Human Urine Using Three Complexing Agents

    Science.gov (United States)

    Swamy, N.; Prashanth, K. N.; Basavaiah, K.

    2015-07-01

    Three simple, rapid, inexpensive, and highly sensitive spectrophotometric methods are described for the quantifi cation of pyrantel pamoate (PYP) in pure drug and formulations. The methods are based on the molecular charge-transfer (CT) complexation reaction involving pyrantel base (PYL) as n-donor and iodine as σ-acceptor (I 2 , method A), and 2,4-dinitrophenol (DNP, method B) or picric acid (PA, method C) as π-acceptors. Spectrophotometrically, the CT complexes showed absorption maxima at 380, 420, and 430 nm, for methods A, B, and C, respectively. Under optimum conditions, Beer's law was obeyed over the concentration ranges 0.12-2.9, 0.12-3.75, and 0.12-2.9 μg/ml for methods A, B, and C, respectively. The apparent molar absorptivity of the CT complexes at the respective λmax are calculated to be 2.63 × 10 5 , 6.91 × 10 4 , and 1.73 × 10 5 l/mol· cm respectively and the corresponding Sandell sensitivity values are 0.0009, 0.003, and 0.0012. The limits of detection (LOD) and quantification (LOQ) are calculated to be (0.02 and 0.07), (0.05 and 0.15), and (0.02 and 0.07) μg/ml with methods A, B, and C, respectively. The intra-day and inter-day accuracy expressed as %RE and precision expressed as %RSD are less than 3%. The methods have been applied to the determination of PYP in tablets, suspensions, and spiked human urine. Parallel assay by a reference method and statistical analysis of the results obtained show no significant difference between the proposed methods and the reference method with respect to accuracy and precision, as evident from the Student's t and variation ratio tests. The accuracy of the methods has been further ascertained by recovery tests via the standard addition technique.

  2. Electron spin resonance and optical absorption spectroscopic studies of Cu2+ ions in aluminium lead borate glasses

    International Nuclear Information System (INIS)

    Highlights: ► It is for the first time to study optical absorption and EPR in these glasses. ► The thermal properties are new and interesting in this glass system. ► It is for the first time to report three optical bands for Cu2+ in oxide glasses. ► The interesting optical results are due to excellent sample preparation. - Abstract: Electron Spin Resonance and optical absorption spectral studies of Cu2+ ions in 5 Al2O3 + 75 B2O3 + (20-z) PbO + z CuO (where z = 0.1–1.5 mol.% of CuO) glasses have been reported. The EPR spectra of all the glasses show resonance signals characteristic of Cu2+ ions at both room and low temperatures. The number of spins and Gibbs energy were calculated at different concentrations and temperatures. From the plot of the ratio of logarithmic number of spins and absolute temperature and the reciprocal of absolute temperature, the entropy and enthalpy have been evaluated. The optical absorption spectra of all the glasses exhibit three bands and these bands have been assigned to 2B1g → 2Eg, 2B1g → 2B2g, and 2B1g → 2A1g transitions in the decreasing order of energy. It is for the first time to observe three optical absorption bands for Cu2+ ions in oxide glasses. Such type of results is due to excellent sample preparation. From the EPR and optical absorption spectroscopies data, the molecular orbital coefficients have been evaluated.

  3. 对乙酰基偶氮氯膦光度法测定烟草中钙的方法研究%Study on Spectrophotometric Determination of Calcium in Tobacc o with p-Acetylchlorophosphonazo

    Institute of Scientific and Technical Information of China (English)

    刘巍; 李忠; 刘思远; 王岚; 施红林; 杨光宇

    2001-01-01

    研究了对乙酰基偶氮氯膦(ACCPP)与钙的显色反应,在pH=8.5的氯化铵-氨水缓冲介质中,乳化剂-OP存在下,ACCPP与钙反应生成1∶1稳定络合物,λmax=680nm,ε =4.01×104L*mol-1*cm-1。钙含量在0—20μg/25mL范围内符合比耳 定律,方法用于烟草样品中钙含量的测定,结果令人满意。%Color reaction of calcium(Ⅱ) with p-acetylchlorophosphonazo (ACCPP) was studied.In the presence of buffer solution pH=8.5 ACCPP can react with calcium(Ⅱ) to form a stable 1∶1 complex.The molar absorptivity is 4.01×104L*mol-1 *cm-1 at 680nm.Beer's law is obeyed in the range of 0—20μg/25mL.This method was applied to the determination of calcium in tobacco with satisfactory results.

  4. Anticancer efficacy and absorption, distribution, metabolism, and toxicity studies of Aspergiolide A in early drug development

    Directory of Open Access Journals (Sweden)

    Wang Y

    2014-10-01

    Full Text Available Yuanyuan Wang, Xin Qi, Dehai Li, Tianjiao Zhu, Xiaomei Mo, Jing LiKey Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of ChinaAbstract: Since the first anthracycline was discovered, many other related compounds have been studied in order to overcome its defects and improve efficacy. In the present paper, we investigated the anticancer effects of a new anthracycline, aspergiolide A (ASP-A, from a marine-derived fungus in vitro and in vivo, and we evaluated the absorption, distribution, metabolism, and toxicity drug properties in early drug development. We found that ASP-A had activity against topoisomerase II that was comparable to adriamycin. ASP-A decreased the growth of various human cancer cells in vitro and induced apoptosis in BEL-7402 cells via a caspase-dependent pathway. The anticancer efficacy of ASP-A on the growth of hepatocellular carcinoma xenografts was further assessed in vivo. Results showed that, compared with the vehicle group, ASP-A exhibited significant anticancer activity with less loss of body weight. A pharmacokinetics and tissue distribution study revealed that ASP-A was rapidly cleared in a first order reaction kinetics manner, and was enriched in cancer tissue. The maximal tolerable dose (MTD of ASP-A was more than 400 mg/kg, and ASP-A was not considered to be potentially genotoxic or cardiotoxic, as no significant increase of micronucleus rates or inhibition of the hERG channel was seen. Finally, an uptake and transport assay of ASP-A was performed in monolayers of Caco-2 cells, and ASP-A was shown to be absorbed through the active transport pathway. Altogether, these results indicate that ASP-A has anticancer activity targeting topoisomerase II, with a similar structure and mechanism to adriamycin, but with much lower toxicity. Nonetheless, further molecular structure optimization is necessary.Keywords: aspergiolide A, anticancer

  5. Graphite Furnace Atomic Absorption Spectrophotometric Method for the Determination of Cadmium in Soil-full Digestion and Microwave Digestion Method Comparison Experiment%石墨炉原子吸收分光光度法测定土壤中的镉-全消解法和微波消解法比对实验

    Institute of Scientific and Technical Information of China (English)

    黄阳晓; 吴剑

    2012-01-01

    The use of microwave digestion method and electric heating board digestion digestion soil standard sample, using graphite furnace atomic absorption spectrometric determination of lead content in solution, comparison of the two methods of precision and accuracy. Microwave digestion method the relative standard deviation was 291%-411%, electric heating plate method for 738 %- 1394 %. With the standard values of the relative difference comparison, microwave digestion method was lower than 5 %, higher than the 19 % electric heating plate method. Microwave digestion method for measured values were higher than the electric heating board digestion.%用微波消解法与全消解法消解土壤标准样品,用石墨炉原子吸收光谱法测定消解液铅含量.比较两种消解方法的精密度和准确度。微波消解法的相对标准偏差为3.8%,全消解法为8.6%。与标准值的相对相差比较,微波消解法低于10%,电热板消解法高于19%。微波消解法的测出值均高于电热板消解法。

  6. Kinetic spectrophotometric determination of trace amounts of selenium and vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Safavi, A.; Sedghy, H.R.; Shams, E. [Dept. of Chemistry, Shiraz Univ. (Iran)

    1999-11-01

    A sensitive kinetic spectrophotometric method has been developed for the determination of Se(IV) over the range of 45 to 4000 ng in 10 mL of solution. The method is based on the catalytic effect of Se(IV) on the reduction reaction of bromate by hydrazinium dichloride, with subsequent reaction of Ponceau S with products of the above reaction (chlorine and bromine), causing color changing of Ponceau S. Method development includes optimization of time interval for measurement of slope, pH, reagents concentration, and temperature. The optimized conditions yielded a theoretical detection limit of 33 ng/10 mL of solution of Se(IV). The interfering effects were studied and removed. The method was applied to the determination of selenium in spiked water, Kjeldahl tablet, selenium tablet, and shampoo. Vanadium(V) has an inhibition effect on the catalyzed reaction of bromate and hydrazine by selenium. Using this effect, V(V) can be determined in the range of 70 to 2500 ng in 10 mL of solution. The optimization procedure includes pH and selenium concentration. An extraction method was used for interference removal. The method was applied to the determination of vanadium in petroleum. (orig.)

  7. Kinetic spectrophotometric determination of the macrolide antibiotic josamycin in formulations.

    Science.gov (United States)

    Al-Majed, Abdulrahman A; Belal, Fathalla; Ibrahim, Kamal E E; Khalil, Nasr Y

    2003-01-01

    A simple kinetic spectrophotometric method was developed for the determination of josamycin in its dosage forms. The method is based on oxidation of the drug with alkaline potassium permanganate at room temperature for a fixed time of 20 min and measuring the produced green color at 611 nm. The absorbance-concentration plot is rectilinear over the range of 2-10 microg/mL (2.4 x 10(6)-1.2 x 10(-5)M) with minimum detectability of 1.0 microg/mL (1.2 x 10(-6)M). The determination of josamycin by fixed concentration and the rate-constant methods is also feasible with the calibration equations obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets, and statistical analysis showed that the results compared favorably with those obtained by reference methods. The effect of sensitizers and surfactants on the performance of the proposed method was also studied. A proposal of the reaction pathway was presented. PMID:12852563

  8. Simultaneous spectrophotometric and mechanical property characterization of skin

    Science.gov (United States)

    Bunegin, Leonid; Moore, Jeffery B.

    2006-02-01

    Both reflectance spectroscopy and the determination Young's Modulus of skin have shown promise for identifying skin pathology. At present, these determinations are carried out using separate methodologies. This study demonstrates a new technology combining digital UV/VIS reflectance spectroscopy and vacuum aspiration for simultaneously determining the reflectance spectrum and mechanical properties of human skin tissue. A small hand held prototype device incorporating fiber-optic light guides into a vacuum channel was calibrated using various elastic materials subjected to increments of stress by vacuum from 0 to 25 in Hg. The intensity of a UV/VIS light beam reflected from the material at each vacuum increment was compared to the resulting material strain. The reflected beam was also spectrophotometrically analyzed. Skin types were similarly evaluated comparing normal and scar tissue and skin of various ages and coloration. An exponential relationship between reflected beam intensity and the amount of strain resulting from vacuum increments was observed. Young's Modulus (calculated from Aoki et. al equation) and spectra from normal skin and scar tissue were in agreement with previously published observations. Age related decreases in skin elasticity were also demonstrated. In the reflectance spectra, oxy and deoxy-hemoglobin absorbance bands were detected, becoming significantly enhanced at increased levels of vacuum. Melanin absorbance was also easily detected and appeared to correlate with skin coloration. Since superficial skin pathologies have characteristic spectroscopic and mechanical properties, this technique may provide a promising new approach for rapid, non-invasive method for the evaluation of skin lesions.

  9. Determination of loratadine in pharmaceuticals by a spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Pavalache Georgeta

    2015-06-01

    Full Text Available The spectrophotometric method for determination of loratadine using tetraiodomercurate has been applied in various pharmaceutical formulations. The results confirmed that recovery value is optimum and the method is valid, thus it can be used in quality control and evaluation of loratadine tablets, oral formulations of mixed composition, oral solutions, etc. The method is easy and simple to apply, does not require complicated equipment and spectrophotometric reading time is reduced, which allows a large number of analyzes in a relatively short time.

  10. Study on Absorption Heat transfer of Two-Dimensionally Constant Curvature Surface Tubes-1

    Science.gov (United States)

    Ogawa, Kiyoshi; Isshiki, Naotsugu

    In order to get better heat transfer coefficient of absorption in actual apparatus, it is considered that the wettability of the surface should be high, and that the thickness of liquid film should not be too thin or too thick all over the surface. So, new conception of two-dimensionally constant curvature surface (CCS) for absorption heat transfer has been introduced for the first time by the authors. First, theoretical CCS section curves of CCS tubes were calculated, and some of them were manufactured for the test. The wettability of CCS is tested and compared to the other finned tubes (radial fin tubes of triangular and rectangular profiles). As may be seen from photographs and compared to the other finned tubes, on the CCS surface, the thickness of liquid has shown to be even all over the surface without creating paticulary thick or thin place, so that, liquid films are very wettable on the CCS surface.

  11. A model for absorption determination of radioactive materials: application in the radio dosimetry and nutrition study

    International Nuclear Information System (INIS)

    A three-parameter model of the sigmoidal relationship is proposed to explain the food passage by intestinal tube. These parameters are: U = intestinal non-absorbed radioactivity; d parameter related to intestinal food dispersion; and t50 = time to maximal appearance of material from the intestinal lumen. In order to illustrate the applications of this model and its validity, the absorption of 65Zn from casein semi-purified diet was evaluated in rats. There was a good agreement between the predicted values and the experimental data when the sigmoidal component was added to the conventional multicompartimental equations. With this kind of model the time to maximal appearance (hours), the true absorption level, the fecal concentration and the intestinal dispersion of the ingested radioactivity material may be determined. (author)

  12. A study into light scattering and absorption by aluminum nanoparticles in PETN

    Science.gov (United States)

    Aduev, B.; Nurmukhametov, D.; Zvekov, A.; Nikitin, A.

    2014-11-01

    The paper is devoted to experimental and theoretical research into nanopartides' optic properties in pentaerythritol tetranitrate (petn) matrix. A photometric sphere was applied for the transmittance and sum of transmittance and reflectance measurement of petn pressed pellets containing aluminum nanoparticles at the light wavelength 643 nm. The theory of light propagation in terms of spherical harmonics solution of radiative transfer equation in the slab geometry with Fresnel boundary conditions was developed. The properties of aluminum nanoparticles were evaluated in terms of Mie theory. The absorbed energy distribution inside the sample was calculated. It was shown that the Beer's type law is applicable approximately. The apparent light absorption cross section determined, which takes into account both scattering and absorption, is bigger than the geometrical one. The aluminum refractive index value, estimated during comparison of theory with the experimental data, agrees well with the handbook's data.

  13. PIXE study on inhibition effect of sodium alginate to the absorption of strontium

    Energy Technology Data Exchange (ETDEWEB)

    Ma Xinpei [Academia Sinica, Beijing, BJ (China). Inst. of Atomic Energy

    1992-12-31

    The sodium alginate extracted from sargassum of South China Sea significantly inhibited the absorption of Sr in human gastrointestinal tract. Because of the identical metabolism dynamics of radioactive Sr and stable Sr, oral medication experiments have been performed by using stable Sr as a tracer. Fifteen adult healthy subjects (10 males and 5 females) were involved and divided into two groups. Concentrations of Sr, Ca, Fe, Cu, and Zn in serum and urine (24 hours) at different times after oral medications were measured by PIXE. It was found from the PIXE results that Sr in serum and in urine were reduced (78 +/- 8.9)% and (78 +/- 11)% respectively by sodium alginate. A reasonable dosage of sodium alginate had little influence to the absorption of Ca, Fe, Cu, and Zn. (author).

  14. Population specific absorption studies for some diet incorporated trace elements : comparison with ICRP data

    International Nuclear Information System (INIS)

    Daily intake and excretion can provide an important information regarding the absorption through the gastro-intestinal tract (f1 factor) of trace elements incorporated in diet. The absorption may depend upon the kind of diet consumed, the content of the fibre, protein etc and it could be quite different for two populations groups with entirely different food habits. ICRP has provided data on the intake and excretion of 63 trace elements by Caucasian population representing North American and European adults. This paper reports intake and excretion of twelve elements Na, K, Ca, Mg, Cu, Mn, Rb, Fe, Zn, Sr, Li and Cr for an urban adult Indian population group and compares with corresponding data on ICRP reference man. (author)

  15. Strontium Localization in Bone Tissue Studied by X-Ray Absorption Spectroscopy

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Raffalt, Anders Christer; Ståhl, Kenny

    2014-01-01

    Strontium has recently been introduced as a pharmacological agent for the treatment and prevention of osteoporosis. We determined the localization of strontium incorporated into bone matrix from dogs treated with Sr malonate by X-ray absorption spectroscopy. A new approach for analyzing the X......-ray absorption spectra resulted in a compositional model and allowed the relative distribution of strontium in the different bone components to be estimated. Approximately 35–45 % of the strontium present is incorporated into calcium hydroxyapatite (CaHA) by substitution of some of the calcium ions occupying...... highly ordered sites, and at least 30 % is located at less ordered sites where only the first solvation shell is resolved, suggesting that strontium is sur- rounded by only oxygen atoms similar to Sr2? in solution. Strontium was furthermore shown to be absorbed in collagen in which it obtains a higher...

  16. Preliminary study of neutron absorption by concrete with boron carbide addition

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Yusof, E-mail: yusofabd@nuclearmalaysia.gov.my; Yusof, Mohd Reusmaazran; Zali, Nurazila Mat; Ahmad, Megat Harun Al Rashid Megat; Yazid, Hafizal [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Ariffin, Fatin Nabilah Tajul; Ahmad, Sahrim [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor (Malaysia); Hamid, Roszilah [Department of Civil and Structural Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor (Malaysia); Mohamed, Abdul Aziz [College of Engineering, Universiti Tenaga National, Jalan Ikram-Uniten, 43000 Kajang, Selangor (Malaysia)

    2014-02-12

    Concrete has become a conventional material in construction of nuclear reactor due to its properties like safety and low cost. Boron carbide was added as additives in the concrete construction as it has a good neutron absorption property. The sample preparation for concrete was produced with different weight percent of boron carbide powder content. The neutron absorption rate of these samples was determined by using a fast neutron source of Americium-241/Be (Am-Be 241) and detection with a portable backscattering neutron detector. Concrete with 20 wt % of boron carbide shows the lowest count of neutron transmitted and this indicates the most neutrons have been absorbed by the concrete. Higher boron carbide content may affect the concrete strength and other properties.

  17. Excited-State Dynamics of Carotenoids Studied by Femtosecond Transient Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ingu; Pang, Yoonsoo [Department of Physics and Photon Science, Gwangju (Korea, Republic of); Lee, Sebok [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

    2014-03-15

    Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-β-caroten-8'-al and 7',7'-dicyano-7'-apo-β-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-β-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the S{sub 2} and S{sub 1} excited states.

  18. Inhibition by Natural Dietary Substances of Gastrointestinal Absorption of Starch and Sucrose in Rats 2. Subchronic Studies

    Directory of Open Access Journals (Sweden)

    Harry G. Preuss, Bobby Echard, Debasis Bagchi, Sidney Stohs

    2007-01-01

    Full Text Available Acute oral consumption of various natural inhibitors of amylase (bean and hibiscus extracts and sucrase (L-arabinose reduce absorption of starch and sucrose respectively in rats and pigs measured by lessened appearance of circulating glucose levels. The present subchronic study was designed to determine whether these selected inhibitors of gastrointestinal starch and sucrose absorption (so-called “carb blockers” remain effective with continued use and to assess their metabolic influences after prolonged intake. Sprague-Dawley rats were gavaged twice daily over nine weeks with either water or an equal volume of water containing a formula that included bean and hibiscus extracts and L-arabinose. To estimate CHO absorption, control and treated Sprague-Dawley rats were gavaged with either water alone or an equal volume of water containing glucose, rice starch, sucrose, or combined rice starch and sucrose. Circulating glucose was measured at timed intervals over four hours. The ability to decrease starch and sucrose absorption use. No toxic effects (hepatic, renal, hematologic were evident. Blood chemistries revealed significantly lower circulating glucose levels and a trend toward decreased HbA1C in the nondiabetic rats receiving the natural formulation compared to control. Subchronic administration of enzyme inhibitors was also associated with many metabolic changes including lowered systolic blood pressure and altered fluid-electrolyte balance. We postulate that proper intake of natural amylase and sucrase inhibitors may be useful in the prevention and treatment of many chronic disorders associated with perturbations in glucose-insulin homeostasis secondary to the rapid absorption of refined CHO.

  19. Study on the interaction between diphenhydramine and erythrosin by absorption,fluorescence and resonance Rayleigh scattering spectra

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In pH 4.5 Britton-Robinson(BR)buffer solution,erythrosin(ET)can react with diphenhydramine(DP)to form a 1:1 ion-association complex,which not only results in the change of the absorption spectra,but also results in the great enhancement of resonance Rayleigh scattering(RRS)and the quenching of fluorescence.Furthermore,a new RRS spectrum will appear,and the maximum RRS wavelength was located at about 580 nm.In this work,the spectral characteristics of the absorption,fluorescence and RRS,the optimum conditions of the reaction and the properties of an analytical chemistry were inves- tigated.A sensitive,simple and new method for the determination of DP by using erythrosin as a probe has been developed.The detection limits for DP were 0.0020μg/mL for RRS method,0.088μg/mL for absorption method and 0.094μg/mL for fluorophotometry.There was a linear relationship between the absorbance,RRS and fluorescence intensities and the drug concentration in the range of 0.0067-2.0, 0.29-6.4 and 0.31-3.2μg/mL,respectively.The effects of the interaction of diphenhydramine and erythrosin on the absorption,fluorescence and resonance Rayleigh scattering spectra were discussed. In light polarization experiment,the polarization of RRS at maximum wavelength was measured to be P =0.9779,and it revealed that the RRS spectrum of DP-ET complex consists mostly of resonance scat- tering and few resonance fluorescence.In this study,enthalpy of formation and mean polarizability were calculated by AM1 quantum chemistry method.In addition,the reaction mechanism and the rea- sons for the enhancement of scattering spectra and the energy transfer between absorption,fluores- cence and RRS were discussed.

  20. Procedure for intercomparison study for trace elements determination in soil samples by absorption spectroscopy

    International Nuclear Information System (INIS)

    In the environmental sampling analysis there is very important to establish an adequate methodologies on the laboratories for improvement the quality of the results obtained, so the establishment of a qualified laboratories network for environmental analysis. The objective of this work is to show the working plan for the analysis of eight elements on a Russian soil sample for an interlaboratory comparison with IAEA, by the Absorption spectroscopy technique using flame. (Author)