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Sample records for reliable derivative spectrophotometric

  1. Second derivative spectrophotometric determination of ...

    African Journals Online (AJOL)

    A new, simple, rapid, wide applicable range and reliable second derivative spectrophotometric method has been developed for determination of cyclophosphamide (CP) in bulk and pharmaceutical dosage forms. Calibration graph is linear in the concentration range of 25 - 200 μg/ml of CP with 10 μg/ml of detection limit and ...

  2. Second derivative spectrophotometric determination of ...

    African Journals Online (AJOL)

    Hemn

    2013-11-13

    Nov 13, 2013 ... olanzapine in pharmaceutical formulation.Int.J.ChemTech. Res.2(1):756-761. Stanisz B, Paszun S, Lesniak M (2009). Validation of UV derivative spectrophotometric method for determination of benazepril hydrochloride in tablets and evaluation of its stability.ActaPoloniaePharmaceutica-Drug Research.

  3. Reliability and accuracy of Crystaleye spectrophotometric system.

    Science.gov (United States)

    Chen, Li; Tan, Jian Guo; Zhou, Jian Feng; Yang, Xu; Du, Yang; Wang, Fang Ping

    2010-01-01

    to develop an in vitro shade-measuring model to evaluate the reliability and accuracy of the Crystaleye spectrophotometric system, a newly developed spectrophotometer. four shade guides, VITA Classical, VITA 3D-Master, Chromascop and Vintage Halo NCC, were measured with the Crystaleye spectrophotometer in a standardised model, ten times for 107 shade tabs. The shade-matching results and the CIE L*a*b* values of the cervical, body and incisal regions for each measurement were automatically analysed using the supporting software. Reliability and accuracy were calculated for each shade tab both in percentage and in colour difference (ΔE). Difference was analysed by one-way ANOVA in the cervical, body and incisal regions. range of reliability was 88.81% to 98.97% and 0.13 to 0.24 ΔE units, and that of accuracy was 44.05% to 91.25% and 1.03 to 1.89 ΔE units. Significant differences in reliability and accuracy were found between the body region and the cervical and incisal regions. Comparisons made among regions and shade guides revealed that evaluation in ΔE was prone to disclose the differences. measurements with the Crystaleye spectrophotometer had similar, high reliability in different shade guides and regions, indicating predictable repeated measurements. Accuracy in the body region was high and less variable compared with the cervical and incisal regions.

  4. [Derivative spectrophotometric and NMR spectroscopic study in pharmaceutical science].

    Science.gov (United States)

    Kitamura, Keisuke

    2007-10-01

    This review starts with an introduction of derivative spectrophotometry followed by a description on the construction of a personal computer-assisted derivative spectrophotometric (DS) system. An acquisition system for inputting digitalized absorption spectra into personal computers and a BASIC program for calculating derivative spectra were developed. Then, applications of the system to drug analyses that are difficult with traditional absorption methods are described. Following this, studies on the interactions of drugs with biological macromolecules by the DS and NMR methods were discussed. An (1)H NMR study elucidated that the small unilamellar vesicle (SUV) has a single membrane made of a phosphatidylcholine bilayer, and that chlorpromazine interacts with both the outer and inner layers. (13)C NMR revealed a reduction of the dissociation constants of phenothiazine drugs due to their interaction with SUV. The partition coefficients of phenothiazine, benzodiazepine and steroid drugs in an SUV-water system and the effects of cholesterol or amino lipids content on these partition coefficients were examined by the DS method. The binding constants of phenothiazine drugs to bovine serum albumin (BSA) and the influence of Na(+), K(+), Cl(-), Br(-), and I(-) on these binding constants were determined by DS. It was found that I(-), Br(-), Cl(-) reduce the binding constants in this order, and that Na(+) and K(+) have no effect. A (19)F NMR study revealed that triflupromazine binds to BSA and human serum albumin in two regions including Site II with different populations, and that a nonsteroidal anti-inflammatory drug, niflumic acid, binds Sites Ia and Ib.

  5. Derivative spectrophotometric method for simultaneous determination of clindamycin phosphate and tretinoin in pharmaceutical dosage forms.

    Science.gov (United States)

    Barazandeh Tehrani, Maliheh; Namadchian, Melika; Fadaye Vatan, Sedigheh; Souri, Effat

    2013-04-10

    A derivative spectrophotometric method was proposed for the simultaneous determination of clindamycin and tretinoin in pharmaceutical dosage forms. The measurement was achieved using the first and second derivative signals of clindamycin at (1D) 251 nm and (2D) 239 nm and tretinoin at (1D) 364 nm and (2D) 387 nm.The proposed method showed excellent linearity at both first and second derivative order in the range of 60-1200 and 1.25-25 μg/ml for clindamycin phosphate and tretinoin respectively. The within-day and between-day precision and accuracy was in acceptable range (CVpharmaceutical dosage form.

  6. Spectrophotometric determination of chlorthalidone in pharmaceutical formulations using different order derivative methods

    Directory of Open Access Journals (Sweden)

    Narmeen S. Abdullah

    2017-05-01

    Full Text Available Simple, repaid and accurate zero-, first- and second-order derivative spectrophotometric methods have been developed for determination of chlorthalidone (CLT in commercially available tablets. Normal spectrophotometric scan (zero order shows maximum absorbance at 276 nm in methanol solution and a good linearity in the range of 10.0–75.0 μg/mL. Linear relations using first (D1 and second (D2 order derivative methods were obtained at 278 and 288 nm for D1 and 286 and 292 nm for D2.The calibration curves were constructed in the range of 1.0–25.0 μg/mL for D1 (R = 0.998 and D2 (R = 0.999. Different analytical validations were determined (accuracy, precision, specificity, recovery, stability and robustness to demonstrate its suitability for routine quality control labs. All the developed methods were successfully applied to a tablet formulation and the results were compared statistically with each other and with those obtained by the HPLC reference method.

  7. First derivative spectrophotometric determination of granisetron hydrochloride in presence of its hydrolytic products and preservative and application to pharmaceutical preparations.

    Science.gov (United States)

    Hewala, Ismail I; Bedair, Mona M; Shousha, Sherif M

    2013-04-01

    Granisetron is a selective 5-HT3 receptor antagonist used in prevention and treatment of chemotherapy-induced nausea and vomiting. The drug is available in tablet dosage form and parenteral dosage form containing benzyl alcohol as a preservative. The main route of degradation of granisetron is through hydrolysis. The present work describes the development of a simple, rapid, and reliable first derivative spectrophotometric method for the determination of granisetron in presence of its hydrolytic products as well as the formulations adjuvant and benzyl alcohol. The method is based on the measurement of the first derivative response of granisetron at 290 nm where the interference of the hydrolytic products, the co-formulated adjuvant and benzyl alcohol is completely eliminated. The proposed method was validated with respect to specificity, linearity, selectivity, accuracy, precision, robustness, detection, and quantification limits. Regression analysis showed good correlation between the first derivative response and the concentration of granisetron over a range of 8-16 μg ml(-1) . Statistical analysis proved the accuracy of the proposed method compared with a reference stability indicating high performance liquid chromatography method. The described method was successfully applied to the determination of granisetron in different batches of tablets and ampoules. The assay results obtained in this study strongly encourage us to apply the validated method for the quality control and routine analysis of tablets and parenteral preparations containing granisetron. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Development of a derivative spectrophotometric method for the determination of fungicide zinc ethylenebisdithiocarbamate using sodium molybdate

    International Nuclear Information System (INIS)

    Kaur, Manpreet; Kaur, Varinder; Malik, Ashok K.; Singh, Baldev; Rao, A.L.J.; Verma, Neelam

    2009-01-01

    A derivative spectrophotometric procedure was developed for the determination of zinc(II) ethylenebisdithiocarbamate, Zineb, after formation of its blue colored complex with sodium molybdate in acidic medium. The Beer's law is obeyed up to 40 μg mL -1 of Zineb at 956 nm. The detection limit was 0.006 μg mL -1 for Zineb when S/N ratio is 3 taking into account various parameters, such as the effect of acid concentration. The interference of a large number of ions on the determination of Zineb was evaluated. Most of the alkaline metals and metal salts did not interfere. The procedure presented proper sensitivity and it was applied for determining Zineb in food stuffs and commercial samples of Dithane Z 78 and Hexathane 75% W.P.. Results were compared with earlier reported methods. Zineb was successfully determined without any interferences in the presence of other dithiocarbamates like Ziram, Thiram, Ferbam etc. (author)

  9. Spectrophotometric method for the analysis of rare earths by first and second order derivatives

    International Nuclear Information System (INIS)

    Deshpande, S.M.; Singh, H.

    1997-01-01

    Spectrophotometric methods are widely used for the analysis of rare earth elements as they are simple, fast, precise and accurate. Many of the rare earth ions in acidic solutions absorb in ultraviolet and visible region of the electromagnetic spectrum. Because of the restricted transition of the 4f electrons the absorption peaks are very sharp and these peaks are used for the qualitative and quantitative analysis of rare elements. When analysis of one or two minor constituents in the mixture of rare earths is involved, it is a straightforward and simple matter, but the analysis of multiple elements from a complex mixture is very difficult because of the mutual interference of the absorption bands. Simultaneous equations of the type: (OD) 1 = C A X Φ A1 + C B X Φ B1 and (OD) 2 = C A X Φ A2 + C B X Φ B2 are also employed to overcome the mutual interference. In this paper first order and second order derivative spectra are used for the analysis of rare earths. It is a simple and effective technique for accurate analysis of rare earths from a complex mixture. Absorption data in the first derivative mode is also presented. Analysis of Nd-Pr-Sm from their synthetic mixtures is reported. (author). 4 refs., 1 tab., 1 ill

  10. Derivative spectrophotometric determination of trace amounts of Tungsten(VI) in real water samples

    International Nuclear Information System (INIS)

    Viswanatha, C.; Ramakrishna Reddy, K.; Devanna, N.; Praveen Kumar, M.D.

    2012-01-01

    2,4-Dimethoxybenzaldehydeisonicotinoylhydrazone (DMBHIH) has been synthesized and characterized with IR, NMR and Mass Spectroscopic methods. A simple and derivative spectrophotometric method has been developed for the determination of trace amounts of W(VI). The reagent forms a yellow coloured water soluble complex with W(VI) in basic medium (pH 8.0). The molar absorptivity and Sandell's sensitivity of coloured species are 3.43 x 10 4 L.mol -1 cm -1 and 0.0049 μg/cm 2 respectively. Beer's law is obeyed in the range 0.4113-6.2138 μg/ml of W(VI) at λ max 394 nm. W(VI) forms 1:1 complex with DMBHIH and stability constant of the complex was 5.22x10 6 . The first and second derivative amplitude was measured at 453 nm and 468 nm. The developed method applied for the determination of W(VI) in alloys and biological samples. (author)

  11. Mean centering of ratio spectra and successive derivative ratio spectrophotometric methods for determination of isopropamide iodide, trifluoperazine hydrochloride and trifluoperazine oxidative degradate

    Directory of Open Access Journals (Sweden)

    Maha M. Abdelrahman

    2016-09-01

    Full Text Available Two sensitive, selective and precise stability indicating methods for the determination of isopropamide iodide (ISO, trifluoperazine hydrochloride (TPZ and trifluoperazine oxidative degradate (DEG were developed and validated. Method A is a successive derivative ratio spectrophotometric one, which depends on the successive derivative of ratio spectra in two steps using 0.1 N HCl as a solvent and measuring TPZ at 250.4 and 257.2 nm, ISO at 223 and 228 nm and DEG at 210.6, 213 and 270.2 nm. Method B is mean centering of ratio spectra which depends on using the mean centered ratio spectra in two successive steps and measuring the mean centered values of the second ratio spectra at 322, 355 and 339 nm for TPZ, ISO and DEG, respectively. Factors affecting the developed methods were studied and optimized, moreover, they have been validated as per ICH guidelines and the results demonstrated that the suggested methods are reliable, reproducible and suitable for routine use with short analysis time. Statistical analysis of the two developed methods with the reported one using F- and Student’s t-test showed no significant difference regarding accuracy and precision.

  12. Spectrophotometric determination of pKa's of 1-hydroxybenzotriazole and oxime derivatives in 95% acetonitrile-water

    International Nuclear Information System (INIS)

    Fathallah, M.F.; Khattab, S.N.

    2011-01-01

    1-hydroxybenzotriazole derivatives are used with carbodiimide as additives to generate active esters during peptide bond formation. They are also used as additives during the peptide bond formation. Dissociation constants of the 1-hydroxybenzotriazole (HOBt) and its derivatives, 1-hydroxy-6-chloro benzotriazole, 1-hydroxy-6-trifluoro methylbenzotriazole, 1-hydroxy-6-nitrobenzo-triazole were determined spectrophotometrically in 95% acetonitrile-water. In addition, 7-aza-1-hydroxybenzotriazole (7-HOAt) and 4-aza-1-hydroxybenzotriazole (4-HOAt) were also studied. Recently, oxyma was reported as a good replacement for the benzotriazole derivatives. As alcoholic components of active esters, the oximes seem to be good leaving groups. Therefore it was expected, that the strongly acidic and nucleophilic oximes, which possess electron-withdrawing groups in the molecule, are suitable as additives during the peptide bond formation. The dissociation constant of some oximes, such as diethyl 2-(hydroxyimino)malonate, ethyl 2-cyano-2-(hydroxyimino)acetate (oxyma), hydroxycarbonimidoyl dicyanide and N-hydroxypicolinimidoyl cyanide in 95% acetonitrile-water are reported. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Dolgorev, A V; Serikov, Yu A; Zolotavin, V L

    1977-03-01

    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 V/sup 3 +/ forms yellow complexes of the composition 1:1 with instability constants 2.2x10/sup -19/, 7.8x10/sup -11/, and 2.2x10/sup -12/, respectively. Complexes of V/sup 3 +/ with derivatives of salicylic acid can be used for determining V(3) content in the presence of V(4).

  14. Derivative Spectrophotometric Method for Estimation of Antiretroviral Drugs in Fixed Dose Combinations

    Science.gov (United States)

    P.B., Mohite; R.B., Pandhare; S.G., Khanage

    2012-01-01

    Purpose: Lamivudine is cytosine and zidovudine is cytidine and is used as an antiretroviral agents. Both drugs are available in tablet dosage forms with a dose of 150 mg for LAM and 300 mg ZID respectively. Method: The method employed is based on first order derivative spectroscopy. Wavelengths 279 nm and 300 nm were selected for the estimation of the Lamovudine and Zidovudine respectively by taking the first order derivative spectra. The conc. of both drugs was determined by proposed method. The results of analysis have been validated statistically and by recovery studies as per ICH guidelines. Result: Both the drugs obey Beer’s law in the concentration range 10-50 μg mL-1,for LAM and ZID; with regression 0.9998 and 0.9999, intercept – 0.0677 and – 0.0043 and slope 0.0457 and 0.0391 for LAM and ZID, respectively.The accuracy and reproducibility results are close to 100% with 2% RSD. Conclusion: A simple, accurate, precise, sensitive and economical procedures for simultaneous estimation of Lamovudine and Zidovudine in tablet dosage form have been developed. PMID:24312779

  15. Spectrophotometric study of the protonation processes of some indole derivatives in sulfuric acid

    Directory of Open Access Journals (Sweden)

    GORAN M. STOJKOVIC

    1999-12-01

    Full Text Available The protonation of 3-methylindole, D-tryptophan, 3-formylindole, 3-acetylindole and indolyl-2-carboxylic acid in sulfuric acid media was studied by UV spectro-scopy. The measurement of the absorbance at four selected wavelengths enabled the calculation of the corresponding molar absorptivities. The results were used to calculate the pKa value of the protonated form of the indole derivatives by the Hammett Method. The Hammett postulate (the slope of the plot log [c(BH+/c(B] vs. H should be equal to 1 was tested. The dissociation constants and solvent parameter m* were also obtained by applying the Excess Acidity Method. The position of the additional protons in the protonated compounds is discussed.

  16. Derivative spectrophotometric method for simultaneous determination of zofenopril and fluvastatin in mixtures and pharmaceutical dosage forms.

    Science.gov (United States)

    Stolarczyk, Mariusz; Maślanka, Anna; Apola, Anna; Rybak, Wojciech; Krzek, Jan

    2015-09-05

    Fast, accurate and precise method for the determination of zofenopril and fluvastatin was developed using spectrophotometry of the first (D1), second (D2), and third (D3) order derivatives in two-component mixtures and in pharmaceutical preparations. It was shown, that the developed method allows for the determination of the tested components in a direct manner, despite the apparent interference of the absorption spectra in the UV range. For quantitative determinations, "zero-crossing" method was chosen, appropriate wavelengths for zofenopril were: D1 λ=270.85 nm, D2 λ=286.38 nm, D3 λ=253.90 nm. Fluvastatin was determined at wavelengths: D1 λ=339.03 nm, D2 λ=252.57 nm, D3 λ=258.50 nm, respectively. The method was characterized by high sensitivity and accuracy, for zofenopril LOD was in the range of 0.19-0.87 μg mL(-1), for fluvastatin 0.51-1.18 μg mL(-1), depending on the class of derivative, and for zofenopril and fluvastatin LOQ was 0.57-2.64 μg mL(-1) and 1.56-3.57 μg mL(-1), respectively. The recovery of individual components was within the range of 100±5%. For zofenopril, the linearity range was estimated between 7.65 μg mL(-1) and 22.94 μg mL(-1), and for fluvastatin between 5.60 μg mL(-1) and 28.00 μg mL(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Acidity Constants Determination of Triazine Dye Derivative in the presence of some Surfactants by Multiwavelength Spectrophotometric and Spectrofluorimetric

    Directory of Open Access Journals (Sweden)

    Ali Yeganeh Faal

    2014-03-01

    Full Text Available In this work, acidity constants protonated form of 4.4'-bis astilbene-2,2'-disulfonic-disodium salts (TRIAZ have been determined spectrophotometrically and spectrofluorimetrically at 25◦C and ionic strength of 0.1M KNO3. A program based on MCR-ALS applied for determination of acidity constants. The results show that the peak values of dye are influenced by the presence of anionic, cationic, and nonionic surfactants. The effects of sodium dodecyl sulfate (SDS, Triton X-100 (TX-100 and cetyl trimethyl ammonium bromide (CTAB as a surface-active agent on the acidic and basic forms, and the spectral properties of dye were studied. Also, we determined the critical micelle concentration (CMC for these surfactants by spectrophotometric and spectrofluorimetric triazine dye probes. In addition, by using of evolving factor analysis (EFA and multivariate curve resolution alternative least squares (MCR-ALS methods, acidity constants were acquired.

  18. Simultaneous spectrophotometric determination of overlapping spectra of paracetamol and caffeine in laboratory prepared mixtures and pharmaceutical preparations using continuous wavelet and derivative transform

    Directory of Open Access Journals (Sweden)

    Ahmed Ashour

    2015-03-01

    Full Text Available In the present paper, two spectrophotometric methods were used for the simultaneous analysis of paracetamol (PCT and caffeine (CAF in their laboratory prepared mixtures and pharmaceutical preparations. Simple spectrophotometric analysis of PCT and CAF is not possible due to their complete spectral overlap. The proposed methods are based on the application of continuous wavelet transform (CWT and derivative transform (using Savitsky–Golay filters on the ratio spectra to predict each of CAF and PCT. Several wavelet families were tested. Coif1 and Sym2 were found to give best results under optimum conditions. The transformed signals of ratio spectra were used to plot the calibration curves for both components. The predictability of the built calibrations was validated through their application on several synthetic mixtures of both drugs. The proposed methods were used for the prediction of CAF and PCT in pharmaceutical preparation. The obtained results were statistically compared to a reference HPLC method. No significant differences were found between the obtained results and those from the reference method. Being simple, rapid, cheap and sensitive, the proposed methods are recommended for the routine daily analysis of these two drugs in their mixtures in quality control laboratories.

  19. p Ka determinations of xanthene derivates in aqueous solutions by multivariate analysis applied to UV-Vis spectrophotometric data

    Science.gov (United States)

    Batistela, Vagner Roberto; Pellosi, Diogo Silva; de Souza, Franciane Dutra; da Costa, Willian Ferreira; de Oliveira Santin, Silvana Maria; de Souza, Vagner Roberto; Caetano, Wilker; de Oliveira, Hueder Paulo Moisés; Scarminio, Ieda Spacino; Hioka, Noboru

    2011-09-01

    Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the p Ka determination and the attribution of each group to the corresponding p Ka value is a very important feature. Attempts to obtain reliable p Ka through the potentiometry titration and the electronic absorption spectrophotometry using the first and second orders derivative failed. Due to the close p Ka values allied to strong UV-Vis spectral overlap, multivariate analysis, a powerful chemometric method, is applied in this work. The determination was performed for eosin Y, erythrosin B, and bengal rose B, and also for other synthesized derivatives such as 2-(3,6-dihydroxy-9-acridinyl) benzoic acid, 2,4,5,7-tetranitrofluorescein, eosin methyl ester, and erythrosin methyl ester in water. These last two compounds (esters) permitted to attribute the p Ka of the phenolic group, which is not easily recognizable for some investigated dyes. Besides the p Ka determination, the chemometry allowed for estimating the electronic spectrum of some prevalent protolytic species and the substituents effects evaluation.

  20. Spectrophotometric Determination of Iron(II and Cobalt(II by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone

    Directory of Open Access Journals (Sweden)

    V. S. Anusuya Devi

    2012-01-01

    Full Text Available Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH reacts with iron(II and cobalt(II to form reddish-brown and yellow-coloured [Fe(II-HNAHBH] and [Co(II-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II-HNAHBH], Beer’s law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II-HNAHBH] complex obeys Beer’s law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content.

  1. New development of spectrophotometric analysis of thorium

    International Nuclear Information System (INIS)

    Yang Xiangzhen

    1992-01-01

    This review covers new development of spectrophotometric determination of thorium since 1980's. The methods include general spectrophotometry, double wavelength spectrophotometry, catalytic spectrophotometry, total differential spectrophotometry, derivative spectrophotometry and fluorescent spectrophotometry, etc

  2. 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.

  3. Spectrophotometric and potentiometric study of uranyl hydrolysis in perchlorate medium. Is derivative spectrophotometry suitable for search of the chemical model?

    International Nuclear Information System (INIS)

    Lubal, P.; Havel, J.

    1997-01-01

    Uranyl hydrolysis (I = 3.00 mol dm -3 NaClO 4 , T = 298.15 K) was studied by potentiometry and spectrophotometry. Numerical analysis of experimental data yielded the logarithmic values of hydrolytic constants for (UO 2 ) p (OH) q (2p-q) species with (p, q) indices: (2, 2) - 6.24 ± 0.02, (3, 5) - 16.80 ± 0.04, and (3, 4) - 12.8 ± 0.1 (potentiometry) and (2, 2) - 6.13 ± 0.02, (3, 5) - 16.81 ± 0.02, and (32, 4) - 12.57 ± 0.02 (average values obtained by derivative spectrophotometry from the first to the fourth order). The spectra of hydrolytic species were deconvoluted and the use of derivative spectrophotometry in equilibria studies has been discussed. (authors)

  4. Collection/concentration of trace uranium for spectrophotometric detection using activated carbon and first-derivative spectrophotometry

    International Nuclear Information System (INIS)

    El-Sayed, A.A.; Hamed, M.M.; El-Reefy, S.; Hmmad, H.A.

    2007-01-01

    The need exists for preconcentration of trace and ultratrace amounts of uranium from environmental, geological and biological samples. The adsorption of uranium on various solids is important from the purification, environmental, and radioactivity waste disposal points of view. A method is described for the determination of traces of uranium using first-derivative spectrophotometry after adsorptive preconcentration of uranium on activated carbon. Various parameters that influence the adsorptive preconcentration of uranium on activated carbon, viz., pH, amounts of activated carbon and time of stirring and interference of metals have been studied. First-derivative spectrophotometry in conjunction with adsorptive preconcentration of uranium on activated carbon is used for determining uranium at concentration levels down to 20 ppb (w/v). (orig.)

  5. Micellar HPLC and derivative spectrophotometric methods for the simultaneous determination of fluconazole and tinidazole in pharmaceuticals and biological fluids.

    Science.gov (United States)

    Belal, F; Sharaf El-Din, M K; Eid, M I; El-Gamal, R M

    2014-04-01

    Micellar high-performance liquid chromatography (HPLC) and first-derivative ultraviolet spectrophotometry were used to simultaneously determine fluconazole (FLZ) and tinidazole (TNZ) in combined pharmaceutical dosage forms. The derivative procedure is based on the linear relationship between the drug concentration and the first derivative amplitudes at 220 and 288 nm for FLZ and TNZ, respectively. The calibration graphs were linear in the range of 1.5-9.0 µg/mL for FLZ and 10.0-60.0 µg/mL for TNZ. Furthermore, an HPLC procedure with ultraviolet detection at 210 nm was developed. For the HPLC procedure, good chromatographic separation was achieved using an ODS C18 column (250 × 4.6 mm i.d.). The mobile phase containing 0.15M sodium dodecyl sulphate, 0.3% triethylamine and 12% n-propanol in 0.02M orthophosphoric acid at pH 5.5 was pumped at a flow rate of 1 mL/min. Indapamide was used as an internal standard. The method showed good linearity over the concentration ranges of 1.5-30.0 and 10.0-200.0 µg/mL, with limits of detection of 0.36 and 2.70 µg/mL and limits of quantification of 1.1 and 8.2 µg/mL for FLZ and TNZ, respectively. The suggested methods were successfully applied for the simultaneous analysis of the drugs in their laboratory prepared mixture, co-formulated tablet and single dosage forms. Moreover the second method was also extended to the determination of the drugs in biological fluids.

  6. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

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    acetylchlorophosphonazo(CPApA) by hydrogen peroxide in 0.10 M phosphoric acid. A novel catalytic kinetic-spectrophotometric method is proposed for the determination of copper based on this principle. Copper(II) can be determined spectrophotometrically ...

  7. Reliability

    OpenAIRE

    Condon, David; Revelle, William

    2017-01-01

    Separating the signal in a test from the irrelevant noise is a challenge for all measurement. Low test reliability limits test validity, attenuates important relationships, and can lead to regression artifacts. Multiple approaches to the assessment and improvement of reliability are discussed. The advantages and disadvantages of several different approaches to reliability are considered. Practical advice on how to assess reliability using open source software is provided.

  8. 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.

  9. Spectrophotometric Determination of Ezetimibe

    Directory of Open Access Journals (Sweden)

    P. Baby Sudha Lakshmi

    2010-01-01

    Full Text Available 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 validated statistically and by recovery studies. The results are compared with those obtained using UV spectrophotometric method in alcohol at 231.7 nm.

  10. Assessing urban and rural neighborhood characteristics using audit and GIS data: derivation and reliability of constructs

    Directory of Open Access Journals (Sweden)

    Laraia Barbara A

    2009-07-01

    Full Text Available Abstract Background Measures to assess neighborhood environments are needed to better understand the salient features that may enhance outdoor physical activities, such as walking and bicycling for transport or leisure. The purpose of this study was to derive constructs to describe neighborhoods using both primary (neighborhood audit and secondary (geographic information systems data. Methods We collected detailed information on 10,770 road segments using an audit and secondary data. The road segment sample was randomly split into an exploratory (60% and validation sample (40% for cross-validation. Using the exploratory sample (n = 6,388, seven a priori constructs were assessed separately (functionality, safety, aesthetics, destinations, incivilities, territorality, social spaces by urbanicity using multi-group confirmatory factor analysis (CFA. Additionally, new a posteriori constructs were derived using exploratory factor analysis (EFA. For cross-validation (n = 4,382, we tested factor loadings, thresholds, correlated errors, and correlations among a posteriori constructs between the two subsamples. Two-week test-retest reliability of the final constructs using a subsample of road segments (n = 464 was examined using Spearman correlation coefficients. Results CFA indicated the a priori constructs did not hold in this geographic area, with the exception of physical incivilities. Therefore, we used EFA to derive a four-factor solution on the exploratory sample: arterial or thoroughfare, walkable neighborhood, physical incivilities, and decoration. Using CFA on the validation sample, the internal validity for these a posteriori constructs was high (range 0.43 to 0.73 and the fit was acceptable. Spearman correlations indicated the arterial or thoroughfare factor displayed near perfect reliability in both urban and rural segments (r = 0.96. Both the physical incivilities factor and the walkable neighborhood factor had substantial to near perfect

  11. Extraction spectrophotometric analyzer

    International Nuclear Information System (INIS)

    Batik, J.; Vitha, F.

    1985-01-01

    Automation is discussed of extraction spectrophotometric determination of uranium in a solution. Uranium is extracted from accompanying elements in an HCl medium with a solution of tributyl phosphate in benzene. The determination is performed by measuring absorbance at 655 nm in a single-phase ethanol-water-benzene-tributyl phosphate medium. The design is described of an analyzer consisting of an analytical unit and a control unit. The analyzer performance promises increased productivity of labour, improved operating and hygiene conditions, and mainly more accurate results of analyses. (J.C.)

  12. Simultaneous removal of binary mixture of Brilliant Green and Crystal Violet using derivative spectrophotometric determination, multivariate optimization and adsorption characterization of dyes on surfactant modified nano-γ-alumina

    Science.gov (United States)

    Zolgharnein, Javad; Bagtash, Maryam; Shariatmanesh, Tahere

    2015-02-01

    The present study deals with the simultaneous removal of Brilliant Green (BG) and Crystal Violet (CV) by surfactant-modified alumina. The utilization of alumina nanoparticles with an anionic surfactant (sodium dodecyl sulfate (SDS)) as a novel and efficient adsorbent is successfully carried out to remove two cationic dyes from aqueous solutions in binary batch systems. A first-order derivative spectrophotometric method is developed for the simultaneous determination of BG and CV in binary solutions. The linear concentration range and limits of detection for the simultaneous determination of BG and CV were found to be: 1-20, 1-15 mg/L, 0.3 and 0.5 mg/L, respectively. The influence of various parameters, such as contact time, initial concentration of dyes and sorbent mass on the dye adsorption is investigated. A response surface methodology achieved through performing the Box-Behnken design is utilized to optimize the removal of dyes by surfactant-modified nanoparticle alumina through a batch adsorption process. The proposed quadratic model resulting from the Box-Behnken design approach fitted very well with the experimental data. The optimal conditions for dye removal were contact time t = 50 min, sorbent dose = 0.036 g, CBG (Initial BG concentration) = 215 mg/L and CCV (Initial CV concentration) = 170 mg/L. Furthermore, FT-IR analysis, the isotherms and kinetics of adsorption were also explored.

  13. Human reliability under sleep deprivation: Derivation of performance shaping factor multipliers from empirical data

    International Nuclear Information System (INIS)

    Griffith, Candice D.; Mahadevan, Sankaran

    2015-01-01

    This paper develops a probabilistic approach that could use empirical data to derive values of performance shaping factor (PSF) multipliers for use in quantitative human reliability analysis (HRA). The proposed approach is illustrated with data on sleep deprivation effects on performance. A review of existing HRA methods reveals that sleep deprivation is not explicitly included at present, and expert opinion is frequently used to inform HRA model multipliers. In this paper, quantitative data from empirical studies regarding the effect of continuous hours of wakefulness on performance measures (reaction time, accuracy, and number of lapses) are used to develop a method to derive PSF multiplier values for sleep deprivation, in the context of the SPAR-H model. Data is extracted from the identified studies according to the meta-analysis research synthesis method and used to investigate performance trends and error probabilities. The error probabilities in test and control conditions are compared, and the resulting probability ratios are suggested for use in informing the selection of PSF multipliers in HRA methods. Although illustrated for sleep deprivation, the proposed methodology is general, and can be applied to other performance shaping factors. - Highlights: • Method proposed to derive performance shaping factor multipliers from empirical data. • Studies reporting the effect of sleep deprivation on performance are analyzed. • Test data using psychomotor vigilance tasks are analyzed. • Error probability multipliers computed for reaction time, lapses, and accuracy measures.

  14. New simple spectrophotometric assay of total carotenes in margarines

    NARCIS (Netherlands)

    Luterotti, S.; Bicanic, D.D.; Pozgaj, R.

    2006-01-01

    Direct and reliable spectrophotometric method for assaying total carotenes (TC) in margarines with the minimum of sample manipulation is proposed. For the first time saponification step used in determination of carotenes in margarines was omitted leading to a substantial cost saving and reduction of

  15. 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)

  16. Differential spectrophotometric determination of plutonium

    International Nuclear Information System (INIS)

    Lecat, J.

    1980-01-01

    Differential spectrophotometric method is used for determination of plutonium reduced to oxydation state III+ by ascorbic acid, at 560 nm. Concentration of solutions is 4 g/l and accuracy of the method is better than 0,3% [fr

  17. SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF MONTELUKAST SODIUM AND BAMBUTEROL HYDROCHLORIDE IN TABLETS

    OpenAIRE

    Patel Satish A; Patel Dhara J; Patel Natavarlal J.

    2011-01-01

    The present manuscript describe simple, sensitive, rapid, accurate, precise and economical first derivative spectrophotometric method for the simultaneous determination of montelukast sodium and bambuterol hydrochloride in combined tablet dosage form. The derivative spectrophotometric method was based on the determination of both the drugs at their respective zero crossing point (ZCP). The first order derivative spectra was obtained in chloroform and the determinations were made at 241 nm (ZC...

  18. Validating and calibrating the Nintendo Wii balance board to derive reliable center of pressure measures.

    Science.gov (United States)

    Leach, Julia M; Mancini, Martina; Peterka, Robert J; Hayes, Tamara L; Horak, Fay B

    2014-09-29

    The Nintendo Wii balance board (WBB) has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation) research domains. Although the WBB has been proposed as an alternative to the "gold standard" laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP) measurement device. In this study, we used the WBB and a laboratory-grade AMTI force plate (AFP) to simultaneously measure the CoP displacement of a controlled dynamic load, which has not been done before. A one-dimensional inverted pendulum was displaced at several different displacement angles and load heights to simulate a variety of postural sway amplitudes and frequencies (<1 Hz). Twelve WBBs were tested to address the issue of inter-device variability. There was a significant effect of sway amplitude, frequency, and direction on the WBB's CoP measurement error, with an increase in error as both sway amplitude and frequency increased and a significantly greater error in the mediolateral (ML) (compared to the anteroposterior (AP)) sway direction. There was no difference in error across the 12 WBB's, supporting low inter-device variability. A linear calibration procedure was then implemented to correct the WBB's CoP signals and reduce measurement error. There was a significant effect of calibration on the WBB's CoP signal accuracy, with a significant reduction in CoP measurement error (quantified by root-mean-squared error) from 2-6 mm (before calibration) to 0.5-2 mm (after calibration). WBB-based CoP signal calibration also significantly reduced the percent error in derived (time-domain) CoP sway measures, from -10.5% (before calibration) to -0.05% (after calibration) (percent errors averaged across all sway measures and in both sway directions). In this study, we characterized the WBB's CoP measurement error under controlled, dynamic

  19. 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 (<0.0001) suggest highly efficiency of CCD model for prediction of data concern to simultaneous 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Validating and Calibrating the Nintendo Wii Balance Board to Derive Reliable Center of Pressure Measures

    Directory of Open Access Journals (Sweden)

    Julia M. Leach

    2014-09-01

    Full Text Available The Nintendo Wii balance board (WBB has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation research domains. Although the WBB has been proposed as an alternative to the “gold standard” laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP measurement device. In this study, we used the WBB and a laboratory-grade AMTI force plate (AFP to simultaneously measure the CoP displacement of a controlled dynamic load, which has not been done before. A one-dimensional inverted pendulum was displaced at several different displacement angles and load heights to simulate a variety of postural sway amplitudes and frequencies (<1 Hz. Twelve WBBs were tested to address the issue of inter-device variability. There was a significant effect of sway amplitude, frequency, and direction on the WBB’s CoP measurement error, with an increase in error as both sway amplitude and frequency increased and a significantly greater error in the mediolateral (ML (compared to the anteroposterior (AP sway direction. There was no difference in error across the 12 WBB’s, supporting low inter-device variability. A linear calibration procedure was then implemented to correct the WBB’s CoP signals and reduce measurement error. There was a significant effect of calibration on the WBB’s CoP signal accuracy, with a significant reduction in CoP measurement error (quantified by root-mean-squared error from 2–6 mm (before calibration to 0.5–2 mm (after calibration. WBB-based CoP signal calibration also significantly reduced the percent error in derived (time-domain CoP sway measures, from −10.5% (before calibration to −0.05% (after calibration (percent errors averaged across all sway measures and in both sway directions. In this study, we characterized the WBB’s CoP measurement error

  1. Spectrophotometric determination of eflornithine hydrochloride ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a spectrophotometric method for the quantitative determination of eflornithine hydrochloride as a pure compound and in pharmaceutical formulations. Methods: The method involved the reaction of the target compound with vanillin reagent at specific pH 5.6 to produce a green reddish color ...

  2. Spectrophotometric determination of association constant

    DEFF Research Database (Denmark)

    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...

  3. Spectrophotometric Determination of Eflornithine Hydrochloride ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a spectrophotometric method for the quantitative determination of eflornithine hydrochloride as a pure compound and in pharmaceutical formulations. Methods: The method involved the reaction of the target compound with vanillin reagent at specific pH. 5.6 to produce a green reddish color ...

  4. reliability reliability

    African Journals Online (AJOL)

    eobe

    Corresponding author, Tel: +234-703. RELIABILITY .... V , , given by the code of practice. However, checks must .... an optimization procedure over the failure domain F corresponding .... of Concrete Members based on Utility Theory,. Technical ...

  5. Spectrophotometric analysis of irradiated spices

    Energy Technology Data Exchange (ETDEWEB)

    Josimovic, L; Cudina, I

    1987-01-01

    Seven different spices (thyme, cinnamon, coriander, caraway, pimento, paprika, black pepper) were treated by gamma radiation at an absorbed dose of 10 kGy, and the effect on chemical quality was determined. The effects of this dose were assessed by spectrophotometric analysis of some water-soluble constituents of spices (carbohydrates; carbonyl compounds) and on the content of water-insoluble steam-volatile oils. The colour of paprika and the content of piperine in pepper held in different packaging materials were measured in unirradiated and irradiated samples as a function of storage time. In all cases irradiation does not bring about any distinct qualitative or quantitative chemical changes based on spectrophotometric analysis of spice extracts.

  6. On the reliable use of satellite-derived surface water products for global flood monitoring

    Science.gov (United States)

    Hirpa, F. A.; Revilla-Romero, B.; Thielen, J.; Salamon, P.; Brakenridge, R.; Pappenberger, F.; de Groeve, T.

    2015-12-01

    Early flood warning and real-time monitoring systems play a key role in flood risk reduction and disaster response management. To this end, real-time flood forecasting and satellite-based detection systems have been developed at global scale. However, due to the limited availability of up-to-date ground observations, the reliability of these systems for real-time applications have not been assessed in large parts of the globe. In this study, we performed comparative evaluations of the commonly used satellite-based global flood detections and operational flood forecasting system using 10 major flood cases reported over three years (2012-2014). Specially, we assessed the flood detection capabilities of the near real-time global flood maps from the Global Flood Detection System (GFDS), and from the Moderate Resolution Imaging Spectroradiometer (MODIS), and the operational forecasts from the Global Flood Awareness System (GloFAS) for the major flood events recorded in global flood databases. We present the evaluation results of the global flood detection and forecasting systems in terms of correctly indicating the reported flood events and highlight the exiting limitations of each system. Finally, we propose possible ways forward to improve the reliability of large scale flood monitoring tools.

  7. Quantitative trait loci markers derived from whole genome sequence data increases the reliability of genomic prediction

    DEFF Research Database (Denmark)

    Brøndum, Rasmus Froberg; Su, Guosheng; Janss, Luc

    2015-01-01

    This study investigated the effect on the reliability of genomic prediction when a small number of significant variants from single marker analysis based on whole genome sequence data were added to the regular 54k single nucleotide polymorphism (SNP) array data. The extra markers were selected...... with the aim of augmenting the custom low-density Illumina BovineLD SNP chip (San Diego, CA) used in the Nordic countries. The single-marker analysis was done breed-wise on all 16 index traits included in the breeding goals for Nordic Holstein, Danish Jersey, and Nordic Red cattle plus the total merit index...... itself. Depending on the trait’s economic weight, 15, 10, or 5 quantitative trait loci (QTL) were selected per trait per breed and 3 to 5 markers were selected to tag each QTL. After removing duplicate markers (same marker selected for more than one trait or breed) and filtering for high pairwise linkage...

  8. Utilizing foreign operating experience to derive reliability data - especially for common mode failures

    International Nuclear Information System (INIS)

    Bongartz, R.; Hennings, W.; Meessen, H.

    1987-11-01

    Failure rates for common mode failures of redundant components of the same design are derived from abnormal occurrences in safety systems of US nuclear power stations for use on a national level. The available raw data of interest for pumps and valves (processed Licensee Event Reports) are progressively re-evaluated and checked for transferability of German conditions. Most of the common mode failures (CMF) experienced affected only part of the redundancies; the homogeneous Marshall-Olkin model is therefore used to determine failure rates for both partial and total failures of redundant components. Some few results based on zero failure statistics and a small data base (four-train systems) seem to be too conservative. On the whole, however, the application of the data determined here does not provide any unrealistically high system unavailabilities. (orig.) [de

  9. Simultaneous Spectrophotometric Determination of Valsartan and ...

    African Journals Online (AJOL)

    Purpose: To develop a direct, simple and extraction-free spectrophotometric method for the simultaneous estimation of valsartan and ezetimibe in pharmaceuticals. Methods: A spectrophotometric method for the determination of valsartan and ezetimibe was developed using acidic dyes, namely, bromophenol blue (BPB) ...

  10. Follow-up of CT-derived airway wall thickness: Correcting for changes in inspiration level improves reliability

    Energy Technology Data Exchange (ETDEWEB)

    Pompe, Esther, E-mail: e.pompe@umcutrecht.nl [Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht (Netherlands); Rikxoort, Eva M. van [Department of Radiology, Radboud University Medical Center, Nijmegen (Netherlands); Mets, Onno M. [Department of Radiology, University Medical Center Utrecht, Utrecht (Netherlands); Charbonnier, Jean-Paul [Department of Radiology, Radboud University Medical Center, Nijmegen (Netherlands); Kuhnigk, Jan-Martin [Institute for Medical Image Computing, Fraunhofer MEVIS, Bremen (Germany); Koning, Harry J. de [Department of Public Health, Erasmus Medical Center, Rotterdam (Netherlands); Oudkerk, Matthijs [University of Groningen, University Medical Center Groningen, Groningen, Department of Radiology (Netherlands); Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Groningen, Department of Radiology (Netherlands); University of Groningen, University Medical Center Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Zanen, Pieter; Lammers, Jan-Willem J. [Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht (Netherlands); Ginneken, Bram van [Department of Radiology, Radboud University Medical Center, Nijmegen (Netherlands); Jong, Pim A. de; Mohamed Hoesein, Firdaus A.A. [Department of Radiology, University Medical Center Utrecht, Utrecht (Netherlands)

    2016-11-15

    Objectives: Airway wall thickness (AWT) is affected by changes in lung volume. This study evaluated whether correcting AWT on computed tomography (CT) for differences in inspiration level improves measurement agreement, reliability, and power to detect changes over time. Methods: Participants of the Dutch-Belgian lung cancer screening trial who underwent 3-month repeat CT for an indeterminate pulmonary nodule were included. AWT on CT was calculated by the square root of the wall area at a theoretical airway with an internal perimeter of 10 mm (Pi10). The scan with the highest lung volume was labelled as the reference scan and the scan with the lowest lung volume was labelled as the comparison scan. Pi10 derived from the comparison scan was corrected by multiplying it with the ratio of CT lung volume of the comparison scan to CT lung volume on the reference scan. Agreement of uncorrected and corrected Pi10 was studied with the Bland-Altman method, reliability with intra-class correlation coefficients (ICC), and power to detect changes over time was calculated. Results: 315 male participants were included. Limit of agreement and reliability for Pi10 was −0.61 to 0.57 mm (ICC = 0.87), which improved to −0.38 to 0.37 mm (ICC = 0.94) after correction for inspiration level. To detect a 15% change over 3 months, 71 subjects are needed for Pi10 and 26 subjects for Pi10 adjusted for inspiration level. Conclusions: Correcting Pi10 for differences in inspiration level improves reliability, agreement, and power to detect changes over time.

  11. Sensitive inexpensive spectrophotometric and spectrofluorimetric analysis of ezogabine, levetiracetam and topiramate in tablet formulations using Hantzsch condensation reaction

    Science.gov (United States)

    Ibrahim, F. A.; El-Yazbi, A. F.; Wagih, M. M.; Barary, M. A.

    2017-09-01

    Two highly sensitive, simple and selective spectrophotometric and spectrofluorimetric assays have been investigated for the analysis of ezogabine, levetiracetam and topiramate in their pure and in pharmaceutical dosage forms. The suggested methods depend on the condensation of the primary amino-groups in the three drugs with acetylacetone and formaldehyde according to Hantzsch reaction yielding highly fluorescent yellow colored dihydropyridine derivatives. The reaction products of ezogabine, levetiracetam and topiramate were measured spectrophotometrically at 418, 390 and 380 nm or spectrofluorimetrically at λem/ex of 495/425 nm, 490/415 nm and 488/410 nm, respectively. Various experimental conditions have been carefully studied to maximize the reaction yield. At the optimum reaction conditions, the calibration curves were rectilinear over the concentration ranges of 8-25, 60-180 and 80-200 μg/mL spectrophotometrically and 0.02-0.2, 0.2-1.2 and 0.2-1.5 μg/mL spectrofluorimetrically for ezogabine, levetiracetam and topiramate, respectively with good correlation coefficients. The suggested methods were applied successfully for the analysis of ezogabine, levetiracetam and topiramate in their commercial tablets with high percentage recoveries and negligible interference from various excipients in pharmaceutical dosage forms. The results were statistically analyzed and showed the absence of any significant difference between both developed and published methods. The procedures were validated and evaluated by the ICH guidelines revealing good reproducibility and accuracy. Therefore, the two proposed methods may be considered of high interest for practical and reliable analysis of ezogabine, levetiracetam and topiramate in pharmaceutical dosage forms.

  12. 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.

  13. Extractive spectrophotometric determination of thorium

    International Nuclear Information System (INIS)

    Venkatesan, M.; Gopalakrishnan, V.; Ramanujam, A.; Nadkarni, M.N.

    1981-01-01

    An extractive spectrophotometric method has been standardized for the analysis of 0.2 to 1.6 milligrams of thorium present in nitric acid solutions. The method involves the extraction of thorium from nitric acid solutions into 0.5 M thenoyl trifluoro acetone (HTTA) in benzene and its direct estimation from the organic extract by spectrophotometry as Thoron colour complex. In this method, interference due to iron upto 5 milligrams can be suppressed by adding ascorbic acid in the ratio of 1:2 prior to HTTA extraction. Uranium(VI) does not interefere even when present in 2000 times the amount of thorium. Plutonium and cerium do not interfere at one milligram level whereas zirconium interferes in this method. The overall error variation and precision of this method has been determined to be +- 3.5%. (author)

  14. Spectrophotometric calibration system for DECam

    Science.gov (United States)

    Rheault, J.-P.; DePoy, D. L.; Marshall, J. L.; Prochaska, T.; Allen, R.; Wise, J.; Martin, E.; Williams, P.

    2012-09-01

    We describe a spectrophotometric calibration system that is being implemented as part of the DES DECam project at the Blanco 4 meter at CTIO. Our calibration system uses a 1nm wide tunable source to measure the instrumental response function of the telescope optics and detector from 300nm up to 1100nm. This calibration will be performed regularly to monitor any change in the transmission function of the telescope during the 5 year survey. The system consists of a monochromator based tunable light source that provides illumination on a dome flat that is monitored by calibrated photodiodes that allow us to measure the telescope throughput as a function of wavelength. Our system has a peak output power of 2 mW, equivalent to a flux of approximately 800 photons/s/pixel on DECam.

  15. 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...... a mixture of room air, pure oxygen and pure nitrogen, ranging from 5% to 100% oxygen. Femoral arterial blood gas analysis and retinal oximetry was performed at each level of inspiratory oxygen fraction. Retinal oximetry was performed using a commercial instrument, the Oxymap Retinal Oximeter T1 (Oxymap ehf...... arterial oxygen saturation and the optical density ratio over retinal arteries revealed an approximately linear relationship (R(2) = 0.74, p = 3.4 x 10(-9)). In order to test the validity of applying the arterial calibration to veins, we compared non-invasive oximetry measurements to invasive pO2...

  16. Extractive Spectrophotometric Determination of Omeprazole in ...

    African Journals Online (AJOL)

    Erah

    Abstract. Purpose: To develop a simple, rapid and selective method for the extractive spectrophotometric determination of .... The colour intensity of the organic layer had shown a very .... considerable attention for quantitative analyses of many ...

  17. Spectrophotometric Determination Of Heavy Metals In Cosmetics

    African Journals Online (AJOL)

    ISSN 1597-6343. Spectrophotometric Determination Of Heavy Metals In Cosmetics ... analysed using atomic absorption spectrophotometer – coupled with a hydride ... presence of arsenic (As), mercury (Hg), cadmium (Cd) and lead. (Pb) in ...

  18. Optimization, Validation and Application of Spectrophotometric ...

    African Journals Online (AJOL)

    ... 3Research Center of Food and Drug Evaluation, Wuhan University, Wuhan 430071, ... Methods: Spectrophotometric HMG-CoA reductase detection in male Wistar ... protein expression in various regulatory ... reagents were analytical grade.

  19. Development of Vanadometric System for Spectrophotometric ...

    African Journals Online (AJOL)

    rugged, and compares well with some complex methods for assay of timolol maleate in ... 3-[[4-(4-morpholinyl)-1, 2, 5-thiadiazol-3-yl] oxy]- ... preparation methods, costly reagents, expertise ..... chemical characterization, UV spectrophotometric.

  20. Development of Ultraviolet Spectrophotometric Method for Analysis ...

    African Journals Online (AJOL)

    HP

    Method for Analysis of Lornoxicam in Solid Dosage. Forms. Sunit Kumar Sahoo ... testing. Mean recovery was 100.82 % for tablets. Low values of % RSD indicate .... Saharty E, Refaat YS, Khateeb ME. Stability-. Indicating. Spectrophotometric.

  1. Validation of different spectrophotometric methods for determination of vildagliptin and metformin in binary mixture

    Science.gov (United States)

    Abdel-Ghany, Maha F.; Abdel-Aziz, Omar; Ayad, Miriam F.; Tadros, Mariam M.

    New, simple, specific, accurate, precise and reproducible spectrophotometric methods have been developed and subsequently validated for determination of vildagliptin (VLG) and metformin (MET) in binary mixture. Zero order spectrophotometric method was the first method used for determination of MET in the range of 2-12 μg mL-1 by measuring the absorbance at 237.6 nm. The second method was derivative spectrophotometric technique; utilized for determination of MET at 247.4 nm, in the range of 1-12 μg mL-1. Derivative ratio spectrophotometric method was the third technique; used for determination of VLG in the range of 4-24 μg mL-1 at 265.8 nm. Fourth and fifth methods adopted for determination of VLG in the range of 4-24 μg mL-1; were ratio subtraction and mean centering spectrophotometric methods, respectively. All the results were statistically compared with the reported methods, using one-way analysis of variance (ANOVA). The developed methods were satisfactorily applied to analysis of the investigated drugs and proved to be specific and accurate for quality control of them in pharmaceutical dosage forms.

  2. Espectrofotometria derivativa: uma estratégia simples para a determinação simultânea de corantes em alimentos Derivative spectrophotometry: a simple strategy for simultaneous determination of food dyes

    Directory of Open Access Journals (Sweden)

    Eliane Cristina Vidotti

    2006-04-01

    Full Text Available A very simple spectrophotometric method is described for resolving binary mixture of the food colorants Sunset Yellow (INS 110 and Tartrazine Yellow (INS 102 by using the first derivative spectra with measurements at zero-crossing wavelengths. Before the spectrophotometric measurements, the dyes were sorbed onto polyurethane foam and recovered in N,N-dimethilformamide. Commercial food products (gelatine and juice powder were analysed by using the proposed method and the HPLC technique. The results are in very good agreement and the differences between the methods is not statistically important. Therefore, the first-order derivative spectrophotometric method is accurate, precise, reliable and could be applied to the routine analysis of food samples.

  3. A simple and reliable approach to docking protein-protein complexes from very sparse NOE-derived intermolecular distance restraints

    International Nuclear Information System (INIS)

    Tang, Chun; Clore, G. Marius

    2006-01-01

    A simple and reliable approach for docking protein-protein complexes from very sparse NOE-derived intermolecular distance restraints (as few as three from a single point) in combination with a novel representation for an attractive potential between mapped interaction surfaces is described. Unambiguous assignments of very sparse intermolecular NOEs are obtained using a reverse labeling strategy in which one the components is fully deuterated with the exception of selective protonation of the δ-methyl groups of isoleucine, while the other component is uniformly 13 C-labeled. This labeling strategy can be readily extended to selective protonation of Ala, Leu, Val or Met. The attractive potential is described by a 'reduced' radius of gyration potential applied specifically to a subset of interfacial residues (those with an accessible surface area ≥ 50% in the free proteins) that have been delineated by chemical shift perturbation. Docking is achieved by rigid body minimization on the basis of a target function comprising the sparse NOE distance restraints, a van der Waals repulsion potential and the 'reduced' radius of gyration potential. The method is demonstrated for two protein-protein complexes (EIN-HPr and IIA Glc -HPr) from the bacterial phosphotransferase system. In both cases, starting from 100 different random orientations of the X-ray structures of the free proteins, 100% convergence is achieved to a single cluster (with near identical atomic positions) with an overall backbone accuracy of ∼2 A. The approach described is not limited to NMR, since interfaces can also be mapped by alanine scanning mutagenesis, and sparse intermolecular distance restraints can be derived from double cycle mutagenesis, cross-linking combined with mass spectrometry, or fluorescence energy transfer

  4. A simple and reliable approach to docking protein-protein complexes from very sparse NOE-derived intermolecular distance restraints

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chun; Clore, G. Marius [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)], E-mail: mariusc@intra.niddk.nih.gov

    2006-09-15

    A simple and reliable approach for docking protein-protein complexes from very sparse NOE-derived intermolecular distance restraints (as few as three from a single point) in combination with a novel representation for an attractive potential between mapped interaction surfaces is described. Unambiguous assignments of very sparse intermolecular NOEs are obtained using a reverse labeling strategy in which one the components is fully deuterated with the exception of selective protonation of the {delta}-methyl groups of isoleucine, while the other component is uniformly {sup 13}C-labeled. This labeling strategy can be readily extended to selective protonation of Ala, Leu, Val or Met. The attractive potential is described by a 'reduced' radius of gyration potential applied specifically to a subset of interfacial residues (those with an accessible surface area {>=} 50% in the free proteins) that have been delineated by chemical shift perturbation. Docking is achieved by rigid body minimization on the basis of a target function comprising the sparse NOE distance restraints, a van der Waals repulsion potential and the 'reduced' radius of gyration potential. The method is demonstrated for two protein-protein complexes (EIN-HPr and IIA{sup Glc}-HPr) from the bacterial phosphotransferase system. In both cases, starting from 100 different random orientations of the X-ray structures of the free proteins, 100% convergence is achieved to a single cluster (with near identical atomic positions) with an overall backbone accuracy of {approx}2 A. The approach described is not limited to NMR, since interfaces can also be mapped by alanine scanning mutagenesis, and sparse intermolecular distance restraints can be derived from double cycle mutagenesis, cross-linking combined with mass spectrometry, or fluorescence energy transfer.

  5. Spectrophotometric observations of symbiotic stars

    International Nuclear Information System (INIS)

    Ipatov, A.P.; Yudin, B.F.

    1985-01-01

    The data of spectrophotometric observations of symbiotic stars Z And, AX Per, CI Cyg, BF Cyg, YY Her, V 443 Her, AG Dra, AG Peg, AS 296, EG And, V 1016 Cyg, and HM Sge are presented. The spectral range of observations is 3300-7500 A, resolution is 50 A. The data obtained allowed to reveal specific characteristics inherent to the radiation of symbiotic stars and to estimate the parameters of their individual components. Analysis of the spectra of symbiotic stars in the range of 1300-7500 A wavelengths suggests a hypothesis, according to which a hot source in the Rayleigh - Jeans spectral range has a less steep inclination in the energy distribution, than a black-body one. A disk, formed during cold star substance accretion through an internal Lagrangian point onto a denser component of the system, can play the role of the source. In this case one manages to obtain the energy distribution in the symbiotic star spectrum consistent with the observed distribution

  6. Europium determination in oxide and oxysulfide luminophors and their wastes by the method of direct and derivative spectrophotometry

    International Nuclear Information System (INIS)

    Mishchenko, V.T.; Aleksandrova, N.N.

    1989-01-01

    Spectrophotometric methods for europium determination in luminophors are proposed. Application of standard and derivative spectrophotometry allows one to determine europium in oxide and oxysulfide luminophors, their wastes and raffinates produced during waste reprocessing quite accurately and reliably. When determining Eu 2 O 3 (Eu 2 O 2 S) mass shares within 4-8 % limits absolute deviation from the mean result makes up to more than ± 0.2 %, relative standard deviation does not exceed 0.02

  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. Reliability of semiquantitative 18F-FDG PET parameters derived from simultaneous brain PET/MRI: A feasibility study

    International Nuclear Information System (INIS)

    Jena, Amarnath; Taneja, Sangeeta; Goel, Reema; Renjen, Pushpendranath; Negi, Pradeep

    2014-01-01

    Purpose: Simultaneous brain PET/MRI faces an important issue of validation of accurate MRI based attenuation correction (AC) method for precise quantitation of brain PET data unlike in PET/CT systems where the use of standard, validated CT based AC is routinely available. The aim of this study was to investigate the feasibility of evaluation of semiquantitative 18 F-FDG PET parameters derived from simultaneous brain PET/MRI using ultrashort echo time (UTE) sequences for AC and to assess their agreement with those obtained from PET/CT examination. Methods: Sixteen patients (age range 18–73 years; mean age 49.43 (19.3) years; 13 men 3 women) underwent simultaneous brain PET/MRI followed immediately by PET/CT. Quantitative analysis of brain PET images obtained from both studies was undertaken using Scenium v.1 brain analysis software package. Twenty ROIs for various brain regions were system generated and 6 semiquantitative parameters including maximum standardized uptake value (SUV max), SUV mean, minimum SUV (SUV min), minimum standard deviation (SD min), maximum SD (SD max) and SD from mean were calculated for both sets of PET data for each patient. Intra-class correlation coefficients (ICCs) were determined to assess agreement between the various semiquantitative parameters for the two PET data sets. Results: Intra-class co-relation between the two PET data sets for SUV max, SUV mean and SD max was highly significant (p < 0.00) for all the 20 predefined brain regions with ICC > 0.9. SD from mean was also found to be statistically significant for all the predefined brain regions with ICC > 0.8. However, SUV max and SUV mean values obtained from PET/MRI were significantly lower compared to those of PET/CT for all the predefined brain regions. Conclusion: PET quantitation accuracy using the MRI based UTE sequences for AC in simultaneous brain PET/MRI is reliable in a clinical setting, being similar to that obtained using PET/CT

  9. Spectrophotometric determination of copper with ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, A; Mustafa, M M; Asma, R N; Sareecha, N [Islamia Univ., Bahawalpur (Pakistan). Chemistry Dept.

    1996-06-01

    Copper has been determined spectrophotometrically by using ascorbic acid as a chromagenic reagent. The complex formed in basic medium is measured for its absorbance at 340 n.m. Interference for 23 cations and 9 anions has also been checked. Effect of pH, time, temperature, ammonia, reagent concentration and interferents has been report. (author).

  10. Development of an indirect spectrophotometric method for ...

    African Journals Online (AJOL)

    A simple and rapid indirect spectrophotometric method for determination of ... of the colored product was measured at 405 nm and pH 3 against a reagent blank. ... The limit of detection and quantification were found to be 0.20±0.03 and ...

  11. Spectrophotometric Determination of Nitrate in Vegetables Using ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    ABSTRACT: A rapid and sensitive spectrophotometric method for the determination of nitrate in vegetables is described. The method is based on the measurement of the absorbance of yellow sodium nitrophenoxide formed via the reaction of phenol with the vegetable-based nitrate in presence of sulphuric acid.

  12. Spectrophotometric determination of proteins associated with ...

    African Journals Online (AJOL)

    Twenty six Aeromonas isolates from fishes, poultry and humans in Zaria were quantified for total soluble proteins (enzymes) profiles in January, 2007 by spectrophotometric (Biuret) method. Isolates were grown on Brain Heart Infusion (BHI) broth, they were incubated at 370C and centrifuged at 1,000 g/dl using harous ...

  13. Spectrophotometric determination of copper with ascorbic acid

    International Nuclear Information System (INIS)

    Majeed, A.; Mustafa, M.M.; Asma, R.N.; Sareecha, N.

    1996-01-01

    Copper has been determined spectrophotometrically by using ascorbic acid as a chromagenic reagent. The complex formed in basic medium is measured for its absorbance at 340 n.m. Interference for 23 cations and 9 anions has also been checked. Effect of pH, time, temperature, ammonia, reagent concentration and interferents has been report. (author)

  14. Uranium fluorides analysis. Titanium spectrophotometric determination

    International Nuclear Information System (INIS)

    Anon.

    Titanium determination in uranium hexafluoride in the range 0.7 to 100 microgrammes after transformation of uranium fluoride in sulfate. Titanium is separated by extraction with N-benzoylphenylhydroxylamine, reextracted by hydrochloric-hydrofluoric acid. The complex titanium-N-benzoylphenylhydroxylamine is extracted by chloroform. Spectrophotometric determination at 400 nm [fr

  15. SPECTROPHOTOMETRIC DETERMINATION OF NITRITE BY ITS ...

    African Journals Online (AJOL)

    Preferred Customer

    sources of nitrite include intensive use of chemical nitrogenous fertilizers, ... The current paper describes another kinetic spectrophotometric method for determination of ... s at λmax = 570 nm (allowing a lag time of 5 s) against water as reference. ... samples and the total amount of the analyte was estimated by applying the ...

  16. Spectrophotometric determination of uranium using quercetin

    International Nuclear Information System (INIS)

    Barros, A.R.

    1972-10-01

    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.) [pt

  17. Spectrophotometric Methods for the Determination of Ketoconazole ...

    African Journals Online (AJOL)

    Spectrophotometric Methods for the Determination of Ketoconazole in Pharmaceutical Dosage Forms. ... Tropical Journal of Pharmaceutical Research ... Methods: The first method (A) was based on the oxidation of the studied drug by a known excess of cerium (IV) as an oxidizing agent and subsequent determination of ...

  18. Kinetic spectrophotometric determination of some fluoroquinolone ...

    African Journals Online (AJOL)

    A simple and sensitive kinetic spectrophotometric method was developed for the determination of some fluoroquinolonea antibiotics; gemifloxacin mesylate, moxifloxacin hydrochloride and gatifloxacin in bulk and in pharmaceutical preparations. The method is based upon a kinetic investigation of the oxidation reaction of ...

  19. Development and Application of Kinetic Spectrophotometric Method ...

    African Journals Online (AJOL)

    Purpose: To develop an improved kinetic-spectrophotometric procedure for the determination of metronidazole (MNZ) in pharmaceutical formulations. Methods: The method is based on oxidation reaction of MNZ by hydrogen peroxide in the presence of Fe(II) ions at pH 4.5 (acetate buffer). The reaction was monitored ...

  20. Spectrophotometric Determination of Trimipramine in Tablet Dosage ...

    African Journals Online (AJOL)

    Purpose: To develop and validate simple, rapid and sensitive spectrophotometric procedures for determination of trimipramine in tablet dosage form. Methods: The methods were based on the interaction of trimipramine as n-electron donor with the ο-acceptor, iodine and various π-acceptors, namely: chloranil (CH), ...

  1. Follow-up of CT-derived airway wall thickness : Correcting for changes in inspiration level improves reliability

    NARCIS (Netherlands)

    Pompe, Esther; van Rikxoort, Eva M; Mets, Onno M; Charbonnier, Jean-Paul; Kuhnigk, Jan-Martin; de Koning, Harry J; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Zanen, Pieter; Lammers, Jan-Willem J; van Ginneken, Bram; de Jong, Pim A; Mohamed Hoesein, Firdaus A A

    2016-01-01

    OBJECTIVES: Airway wall thickness (AWT) is affected by changes in lung volume. This study evaluated whether correcting AWT on computed tomography (CT) for differences in inspiration level improves measurement agreement, reliability, and power to detect changes over time. METHODS: Participants of the

  2. Follow-up of CT-derived airway wall thickness : Correcting for changes in inspiration level improves reliability

    NARCIS (Netherlands)

    Pompe, Esther; van Rikxoort, Eva M.; Mets, Onno M.; Charbonnier, Jean-Paul; Kuhnigk, Jan-Martin; de Koning, Harry J.; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Zanen, Pieter; Lammers, Jan-Willem J.; van Ginneken, Bram; de Jong, Pim A.; Hoesein, Firdaus A. A. Mohamed

    2016-01-01

    Objectives: Airway wall thickness (AWT) is affected by changes in lung volume. This study evaluated whether correcting AWT on computed tomography (CT) for differences in inspiration level improves measurement agreement, reliability, and power to detect changes over time. Methods: Participants of the

  3. 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

    2015-11-05

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Liquid chromatographic and spectrophotometric methods for the determination of erythromycin stearate and trimethoprim in tablets

    Directory of Open Access Journals (Sweden)

    Sonia T. Hassib

    2011-12-01

    Full Text Available Simple, accurate and precise reversed-phase liquid chromatographic (LC and spectrophotometric methods have been developed and validated for the determination of erythromycin stearate (ERS and trimethoprim (TMP in mixture. In LC method, chromatographic separation was achieved on a Symmetry® Waters C18 column (150 × 4.6 mm, 5 μm based on isocratic elution using a mobile phase consisting of potassium dihydrogen phosphate buffer pH (9:acetonitrile:water (25:100:50, v/v/v at a flow rate of 1.6 ml min−1 with UV detection at 210 nm for ERS and 280 nm for TMP. Besides, two spectrophotometric methods were applied after reaction with perchloric acid (12 M which gives a colored product with ERS. Then, the spectral interference between the colored product of ERS and TMP was resolved by either ratio spectra derivative spectrophotometry in the first spectrophotometric method or chemometric techniques, namely classical least-squares (CLS, principal component regression (PCR and partial least-squares regression (PLS in the second spectrophotometric method. The results were statistically compared using one-way analysis of variance (ANOVA. The methods developed were satisfactorily applied to the analysis of the pharmaceutical preparation containing the two drugs and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

  5. Separation and spectrophotometric determination of elements

    International Nuclear Information System (INIS)

    Marczenko, Z.

    1986-01-01

    This book is a useful text intended as a reference for the laboratory that is either involved in spectrophotometric analysis or requires separations prior to analysis by any method. It attempts to cover a diverse series of topics in fewer than 700 pages. Part I of the book covers general topics such as separation schemes (solvent extraction, precipitation, volatility, ion exchange), principles and instrumentation used for spectrophotometry, and color reagents in only 119 pages. Entire books have been written on each of those subjects. The author must therefore resort to extensive referencing to cover each subject adequately. Part II, Methods for Separation and Determination of Individual Elements, discusses all elements - both nonmetals and metals and major procedures for the separation and spectrophotometric determination of each element are adequately covered

  6. Spectrophotometric determination of fluoride with alizarin complexone

    Energy Technology Data Exchange (ETDEWEB)

    Marczenko, Z; Lenarczyk, L [Politechnika Warszawska (Poland)

    1976-01-01

    The modification of direct spectrophotometric method of fluoride determination by alizarin complexone has been developed. It was shown that the lanthanum alizarin complexone chelate is more convenient than that of cerium (3). The influence of acetone, dioxane and dimethyl sulphoxide in water solution on the increase of sensitivity of the method and the rate of colour reaction has been determined. The optimal pH ranges for the reaction with lanthanum and cerium (3) have been estimated. Some amines having a large molecule are useful for extraction of blue fluoride complex with isobutanol. Dioctylamine was applied in a new extraction spectrophotometric procedure of fluoride determination. Conditions in reagent have been established. Both variants of the method have been applied to the fluoride determination in several chemicals. The obtained results show a good precision and accuracy.

  7. Spectrophotometric titration of zirconium in siliceous materials

    International Nuclear Information System (INIS)

    Sugawara, K.F.; Su, Y.-S.; Strzegowski, W.R.

    1978-01-01

    An accurate and selective complexometric titration procedure based upon a spectrophotometrically detected end-point has been developed for the determination of zirconium in glasses, glass-ceramics and refractories. A p-bromomandelic acid separation step for zirconium imparts excellent selectivity to the procedure. The method is particularly important for the 1 to 5% concentration range where a simple, accurate and selective method for the determination of zirconium has been lacking. (author)

  8. [Spectrophotometric and HPLC evaluation of ceftazidime stability].

    Science.gov (United States)

    Palade, B; Cioroiu, B; Lazăr, Doina; Corciovă, Andreia; Lazăr, M I

    2010-01-01

    In this paper we followed up the stability of ceftazidime, raw material used in drug industry. Matherials and methods: We used three spectrophotometric methods based on ceftazidime property to form complexes with p-chloranilic acid (ac. p-CA), 3-methylbenzothiazolin-2-on hydrazone (MBTH) and N-(1-naphtil) etilendiamine (NEDA) and a chromatographic method (HPLC). Our results revealed that the substances analyzed maintained minimum content allowable.

  9. Derivative spectrophotometric determination of trace lead in alloys ...

    African Journals Online (AJOL)

    diethylaminophenol-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 4.0–6.0 from a large volume of aqueous solutions of various samples. After filtration, the solid mass consisting of the lead complex and ...

  10. Derivation of centers and axes of rotation for wrist and fingers in a hand kinematic model: methods and reliability results.

    Science.gov (United States)

    Cerveri, P; Lopomo, N; Pedotti, A; Ferrigno, G

    2005-03-01

    In the field of 3D reconstruction of human motion from video, model-based techniques have been proposed to increase the estimation accuracy and the degree of automation. The feasibility of this approach is strictly connected with the adopted biomechanical model. Particularly, the representation of the kinematic chain and the assessment of the corresponding parameters play a relevant role for the success of the motion assessment. In this paper, the focus is on the determination of the kinematic parameters of a general hand skeleton model using surface measurements. A novel method that integrates nonrigid sphere fitting and evolutionary optimization is proposed to estimate the centers and the functional axes of rotation of the skeletal joints. The reliability of the technique is tested using real movement data and simulated motions with known ground truth 3D measurement noise and different ranges of motion (RoM). With respect to standard nonrigid sphere fitting techniques, the proposed method performs 10-50% better in the best condition (very low noise and wide RoM) and over 100% better with physiological artifacts and RoM. Repeatability in the range of a couple of millimeters, on the localization of the centers of rotation, and in the range of one degree, on the axis directions is obtained from real data experiments.

  11. Determination of Modafinil in Tablet Formulation Using Three New Validated Spectrophotometric Methods

    International Nuclear Information System (INIS)

    Basniwal, P.K.; Jain, D.; Basniwal, P.K.

    2014-01-01

    In this study, three new UV spectrophotometric methods viz. linear regression equation (LRE), standard absorptivity (SA) and first order derivative (FOD) method were developed and validated for determination of modafinil in tablet form. The Beer-Lamberts law was obeyed as linear in the range of 10-50 μg/ mL and all the methods were validated for linearity, accuracy, precision and robustness. These methods were successfully applied for assay of modafinil drug content in tablets in the range of 100.20 - 100.42 %, 100.11 - 100.58 % and 100.25 - 100.34 %, respectively with acceptable standard deviation (less than two) for all the methods. The validated spectrophotometric methods may be successfully applied for assay, dissolution studies, bio-equivalence studies as well as routine analysis in pharmaceutical industries. (author)

  12. Spectrophotometric Determination of Zinc Using 7-(4-Nitrophenylazo-8-Hydroxyquinoline-5-Sulfonic Acid

    Directory of Open Access Journals (Sweden)

    Korn Maria das Graças Andrade

    1999-01-01

    Full Text Available A sensitive and selective spectrophotometric method is proposed for the rapid determination of zinc(II using an 8-hydroxyquinoline derivative, 7-(4-nitrophenylazo-8-hydroxyquinoline-5-sulfonic acid (p-NIAZOXS, as a new spectrophotometric reagent. The reaction between the p-NIAZOXS and zinc(II is instantaneous at pH 9.2 (borax buffer and the absorbance remains stable for over 24 h. The method allows the determination of zinc over the range of 0.05-1.0 mug mL-1 with a molar absorptivity of 3.75x10(4 L mol-1 cm-1 and features a detection limit of 15 ng mL-1. The proposed method has been successfully applied to the determination of zinc in several pharmaceutical preparations and copper alloys. The precision (R.S.D. < 2% and the accuracy obtained were satisfactory.

  13. Reliability engineering

    International Nuclear Information System (INIS)

    Lee, Chi Woo; Kim, Sun Jin; Lee, Seung Woo; Jeong, Sang Yeong

    1993-08-01

    This book start what is reliability? such as origin of reliability problems, definition of reliability and reliability and use of reliability. It also deals with probability and calculation of reliability, reliability function and failure rate, probability distribution of reliability, assumption of MTBF, process of probability distribution, down time, maintainability and availability, break down maintenance and preventive maintenance design of reliability, design of reliability for prediction and statistics, reliability test, reliability data and design and management of reliability.

  14. Salicylate-spectrophotometric determination of inorganic monochloramine

    International Nuclear Information System (INIS)

    Tao Hui; Chen Zhonglin; Li Xing; Yang Yanling; Li Guibai

    2008-01-01

    On the basis of classical Berthelot reaction, a simple salicylate-spectrophotometric method was developed for quantitative determination of inorganic monochloramine in water samples. With the catalysis of disodium pentacyanonitrosylferrate(III), inorganic monochloramine reacts with salicylate in equimolar to produce indophenol compound which has an intense absorption at 703 nm. Parameters that influence method performance, such as pH, dosage of salicylate and nitroprussiate and reaction time, were modified to enhance the method performance. By using this method, inorganic monochloramine can be distinguished from organic chloramines and other inorganic chlorine species, such as free chlorine, dichloramine, and trichloramine. The molar absorptivities of the final products formed by these compounds are below ±3% of inorganic monochloramine, because of the α-N in them have only one exchangeable hydrogen atom, and cannot react with salicylate to produce the indophenol compound. The upper concentrations of typical ions that do not interfere with the inorganic monochloramine determination are also tested to be much higher than that mostly encountered in actual water treatment. Case study demonstrates that the results obtained from this method are lower than DPD-titrimetric method because the organic chloramines formed by chlorination of organic nitrogenous compounds give no response in the newly established method. And the result measured by salicylate-spectrophotometric method is coincident with theoretical calculation

  15. Spectrophotometric and Spectrofluorimetric Studies on Azilsartan Medoxomil and Chlorthalidone to be Utilized in Their Determination in Pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Walid M. Ebeid

    2014-01-01

    Full Text Available The recently approved angiotensin II receptor blocker, azilsartan medoxomil (AZL, was determined spectrophotometrically and spectrofluorimetrically in its combination with chlorthalidone (CLT in their combined dosage form. The UV-spectrophotometric technique depends on simultaneous measurement of the first derivative spectra for AZL and CLT at 286 and 257 nm, respectively, in methanol. The spectrofluorimetric technique depends on measurement of the fourth derivative of the synchronous spectra intensities of AZL in presence of CLT at 298 nm in methanol. The effects of different solvents on spectrophotometric and spectrofluorimetric responses were studied. For, the spectrofluorimetric study, the effect of pH and micelle-assisted fluorescence enhancement were also studied. Linearity, accuracy, and precision were found to be satisfactory over the concentration ranges of 8-50 μg mL −1 and 2-20 μg mL −1 for AZL and CLT, respectively, in the spectrophotometric method as well as 0.01-0.08 μg mL −1 for AZL in the spectrofluorimetric method. The methods were successfully applied for the determination of the studied drugs in their co-formulated tablets. The developed methods are inexpensive and simple for the quality control and routine analysis of the cited drugs in bulk and in pharmaceuticals.

  16. Simultaneous determination of moxifloxacin and cefixime by first and ratio first derivative ultraviolet spectrophotometry

    Directory of Open Access Journals (Sweden)

    Attimarad Mahesh

    2012-09-01

    Full Text Available Abstract Background The new combination of moxifloxacin HCl and cefixime trihydrate is approved for the treatment of lower respiratory tract infections in adults. At initial formulation development and screening stage a fast and reliable method for the dissolution and release testing of moxifloxacin and cefixime were highly desirable. The zero order overlaid UV spectra of moxifloxacin and cefixime showed >90% overlapping. Hence, simple, accurate precise and validated two derivative spectrophotometric methods have been developed for the determination of moxifloxacin and cefixime. Methods In the first derivative spectrophotometric method varying concentration of moxifloxacin and cefixime were prepared and scanned in the range of 200 to 400 nm and first derivative spectra were calculated (n = 1. The zero crossing wavelengths 287 nm and 317.9 nm were selected for determination of moxifloxacin and cefixime, respectively. In the second method the first derivative of ratio spectra was calculated and used for the determination of moxifloxacin and cefixime by measuring the peak intensity at 359.3 nm and 269.6 nm respectively. Results Calibration graphs were established in the range of 1–16 μg /mL and 1–15 μg /mL for both the drugs by first and ratio first derivative spectroscopic methods respectively with good correlation coefficients. Average accuracy of assay of moxifloxacin and cefixime were found to be 100.68% and 98 93%, respectively. Relative standard deviations of both inter and intraday assays were less than 1.8%. Moreover, recovery of moxifloxacin and cefixime was more than 98.7% and 99.1%, respectively. Conclusions The described derivative spectrophotometric methods are simple, rapid, accurate, precise and excellent alternative to sophisticated chromatographic techniques. Hence, the proposed methods can be used for the quality control of the cited drugs and can be extended for routine analysis of the drugs in formulations.

  17. REVIEW ARTICLE: Spectrophotometric applications of digital signal processing

    Science.gov (United States)

    Morawski, Roman Z.

    2006-09-01

    Spectrophotometry is more and more often the method of choice not only in analysis of (bio)chemical substances, but also in the identification of physical properties of various objects and their classification. The applications of spectrophotometry include such diversified tasks as monitoring of optical telecommunications links, assessment of eating quality of food, forensic classification of papers, biometric identification of individuals, detection of insect infestation of seeds and classification of textiles. In all those applications, large numbers of data, generated by spectrophotometers, are processed by various digital means in order to extract measurement information. The main objective of this paper is to review the state-of-the-art methodology for digital signal processing (DSP) when applied to data provided by spectrophotometric transducers and spectrophotometers. First, a general methodology of DSP applications in spectrophotometry, based on DSP-oriented models of spectrophotometric data, is outlined. Then, the most important classes of DSP methods for processing spectrophotometric data—the methods for DSP-aided calibration of spectrophotometric instrumentation, the methods for the estimation of spectra on the basis of spectrophotometric data, the methods for the estimation of spectrum-related measurands on the basis of spectrophotometric data—are presented. Finally, the methods for preprocessing and postprocessing of spectrophotometric data are overviewed. Throughout the review, the applications of DSP are illustrated with numerous examples related to broadly understood spectrophotometry.

  18. High precision spectrophotometric analysis of thorium

    International Nuclear Information System (INIS)

    Palmieri, H.E.L.

    1984-01-01

    An accurate and precise determination of thorium is proposed. Precision of about 0,1% is required for the determination of macroquantities of thorium when processed. After an extensive literature search concerning this subject, spectrophotometric titration has been chosen, using dissodium ethylenediaminetetraacetate (EDTA) solution and alizarin-S as indicator. In order to obtain such a precision, an amount of 0,025 M EDTA solution precisely measured has been added and the titration was completed with less than 5 ml of 0,0025 M EDTA solution. It is usual to locate the end-point graphically, by plotting added titrant versus absorbance. The non-linear minimum square fit, using the Fletcher e Powell's minimization process and a computer programme. Besides the equivalence point, other parameters of titration were determined: the indicator concentration, the absorbance of the metal-indicator complex, and the stability constants of the metal-indicator and the metal-EDTA complexes. (Author) [pt

  19. Thorium spectrophotometric analysis with high precision

    International Nuclear Information System (INIS)

    Palmieri, H.E.L.

    1983-06-01

    An accurate and precise determination of thorium is proposed. Precision of about 0,1% is required for the determination of macroquantities of thorium processed. After an extensive literature search concerning this subject, spectrophotometric titration has been chosen, using disodium ethylenediaminetetraacetate (EDTA) solution and alizarin S as indicator. In order to obtain such a precision, an amount of 0,025 M EDTA solution precisely measured has been added and the titration was completed with less than 5 ml of 0,0025 M EDTA solution. It is usual to locate the end-point graphically, by plotting added titrant versus absorbance. The non-linear minimum square fit, using the Fletcher e Powell's minimization process and a computer program. (author)

  20. DECal: A Spectrophotometric Calibration System For DECam.

    Science.gov (United States)

    Rheault, Jean-Philippe; DePoy, D. L.; Marshall, J. L.; Prochaska, T.; Allen, R.; Wise, J.; Martin, E.

    2012-01-01

    We present preliminary results for a spectrophotometric calibration system that is being implemented as part of the DES DECam project at the Blanco 4 meter at CTIO. Our calibration system uses a 2nm wide tunable source to measure the instrumental response function of the telescope from 300nm up to 1100nm. This calibration will be performed regularly to monitor any change in the transmission function. The system consists of a monochromator based tunable light source that provides illumination on a dome flat that is monitored by calibrated photodiodes and allow us to measure the throughput as a function of wavelength. Our system has an output power of 2 mW, equivalent to a flux of approximately 800 photons/s/pixel on DECam. Preliminary results of the measure of the throughput of the telescope will be presented.

  1. Spectrophotometric methods for determining noble metals

    International Nuclear Information System (INIS)

    Gur'eva, R.F.; Savvin, S.B.

    2002-01-01

    The main trends of the development of spectrophotometric methods for determining noble metals (NMs) including ruthenium are considered. One of these trends is the synthesis and study of new, highly sensitive and selective organic reagents for determining NMs in solutions and solid phase. Another trend is the search for and developing of new methodological approaches (techniques) and color reactions, including those that involve modified and immobilized reagents. The third trend includes the improvement of equipment and automation. It is shown that the present-day spectrophotometry can provide the determination of NMs in samples with concentrations from several to 10 -4 % (photometry and differential photometry) and down to 10 -7 % (test and sorption-spectroscopic methods based on photometry and diffuse-reflectance spectroscopy, including the use of chromaticity functions) [ru

  2. Spectrophotometric determination of silicon in silumin matrix

    International Nuclear Information System (INIS)

    Samanta, Papu; Pandey, K.L.; Kumar, Pradeep; Bagchi, A.C.; Abdulla, K.K.

    2015-01-01

    In dispersion fuel, fissile material is dispersed in inert matrix. Aluminum-silicon-nickel (silumin) alloy is employed as inert matrix owing to its high thermal conductivity, high castability, high corrosion resistance. All these properties depend on the chemical composition and the structure of silumin. Silicon is stringent specification in silumin. A spectrophotometric method has been developed for the determination of silicon content in silumin matrix. Silumin matrix was fused with LiOH and subsequent dissolution in water along with few drops of conc. sulphuric acid. The molybodo-silicic formed by the addition of ammonium molybdate is reduced to molybdenum blue by ascorbic acid in the presence of antimony. The absorbance was measured at 810 nm. Aluminum and nickel were found to be non-interfering with the silicon determination. (author)

  3. 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 %.

  4. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation

    Directory of Open Access Journals (Sweden)

    Hanan A. Merey

    2017-01-01

    Full Text Available Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY and Flunixin Meglumine (FLU. The first method, dual wavelength (DW, depends on measuring the difference in absorbance (ΔA 273.4–327 nm for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7–275.7 nm. The second method, first-derivative spectrophotometric method (1D, depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5–324.8 nm and ΔP 249.6–286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD, depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones.

  5. Spectrophotometric determination of some metal ions using hydrazones

    International Nuclear Information System (INIS)

    Mohammed, M. S.

    2000-05-01

    In this research many starting materials were prepared, like methyl salicylate and salicylic acid hydrazide from which different derivatives of hydrazones were synthesized by coupling with carbonyl compounds like benzil monoxime and benzil mono hydrazone which are prepared and others like salicylaldehyde and benzoin. The hydrazones that were synthesized are salicylaldehyde salicylic acid hydrazone, benzoin salicylic acid hydrazone, benzil mono hydrazone salicylic acid hydrazone and benzil monoxime salicylic acid hydrazone. These reagents were determined by different methods, IR spectrophotometric determination, the nitrogen content method and melting point determination. These hydrazones act as ligands for determination of some metal ions by making different coloured complexes that were prepared for eight hydrazones with eight metal ions U (VI), Fe (II), Fe (III), Co (II), V (II), Mo (VI), Ni (II) and Cu (II). These complexes were determined by ultraviolet and visible spectrophotometer (UV/VIS) to detect their absorbance and wavelengths (λ max). The two hydrazones salicylaldehyde salicylic acid-hydrazone and benzoin salicylic acid hydrazone, were selected for determination of five metal ions (Fe (II), Fe (III), U (VI), Ni (II) and Cu (II)), using two micelles sodium n-dodecyl sulphate and pyridinium hexa decyl bromide mono hydrate. Their absorbance and wavelengths were detected using UV/VIS spectrophotometer. (Author)

  6. Spectrophotometric Determination of Cilostazol in Tablet Dosage Form

    African Journals Online (AJOL)

    Erah

    Purpose: To develop simple, rapid and selective spectrophotometric methods for ... Conclusion: These validated methods may be useful for routine analysis of cilostazol ... Keywords: Cilostazol tablets, UV spectrophotometry, Linear regression ...

  7. Study on the Solid Phase Extraction and Spectrophotometric ...

    African Journals Online (AJOL)

    NJD

    Spectrophotometric Determination of Mercury in Water and. Biological ... 1Department of Chemistry, Yunnan University, Kunming, 650091, P.R. China. 2Department of ... (such as higher enrichment factor, reduced contamination of the.

  8. Spectrophotometric and Voltammetric Studies on the Interaction of ...

    African Journals Online (AJOL)

    0.84V(vs. SCE) also changed correspondingly without change of the peak potential, which also indicated that the binding reaction had taken place. Under the selected conditions a new spectrophotometric analytical method was established for ...

  9. Spectrophotometric observations of very low ionization HII regions in the LMC

    International Nuclear Information System (INIS)

    Pena, M.; Ruiz, M.T.; Rubio, M.

    1987-01-01

    Optical spectrophotometric observations of 17 very low ionization HII regions of the LMC are reported. Physical conditions and chemical composition of these objects are derived from the emission line intensities. The average chemical abundances obtained are: log O/H=8.49+-0.08, log N/H=6.91+-0.07 and log S/H=6.89+-0.10. We do not find evidence of any composition gradient in the LMC. The HII regions in the vicinity of the detected molecular cloud complexes show higher nebular reddening. (Author)

  10. Spectrophotometric determination of substrate-borne polyacrylamide.

    Science.gov (United States)

    Lu, Jianhang; Wu, Laosheng

    2002-08-28

    Polyacrylamides (PAMs) have wide application in many industries and in agriculture. Scientific research and industrial applications manifested a need for a method that can quantify substrate-borne PAM. The N-bromination method (a PAM analytical technique based on N-bromination of amide groups and spectrophotometric determination of the formed starch-triiodide complex), which was originally developed for determining PAM in aqueous solutions, was modified to quantify substrate-borne PAM. In the modified method, the quantity of substrate-borne PAM was converted to a concentration of starch-triiodide complex in aqueous solution that was then measured by spectrophotometry. The method sensitivity varied with substrates due to sorption of reagents and reaction intermediates on the substrates. Therefore, separate calibration for each substrate was required. Results from PAM samples in sand, cellulose, organic matter burnt soils, and clay minerals showed that this method had good accuracy and reproducibility. The PAM recoveries ranged from 95.8% to 103.7%, and the relative standard deviations (n = 4) were application and facilitating PAM-related research.

  11. The Spectrophotometric Analysis and Modeling of Sunscreens

    Science.gov (United States)

    Walters, Christina; Keeney, Allen; Wigal, Carl T.; Johnston, Cynthia R.; Cornelius, Richard D.

    1997-01-01

    Sunscreens and their SPF (Sun Protection Factor) values are the focus of this experiment that includes spectrophotometric measurements and molecular modeling. Students suspend weighed amounts of sunscreen lotions graded SPF 4, 6, 8, 15, 30, and 45 in water and dissolve aliquots of the aqueous suspensions in propanol. The expected relationship of absorbance proportional to log10(SPF) applies at 312 nm where a maximum in absorbance occurs for the sunscreen solutions. Results at 330 nm give similar results and are more accessible using spectrometers routinely available in the introductory laboratory. Sunscreens constitute a suitable class of compounds to use for modeling electronic spectra, and using the computer for the active ingredients ethylhexyl para-methoxycinnamate, oxybenzone, 2-ethylhexyl salicylate, and octocrylene found in commercially available formulations typically predicts the absorption maxima within 10 nm. This experiment lets students explore which compounds have the potential to function as sunscreen agents and thereby see the importance of a knowledge of chemistry to the formulation of household items.

  12. Spectrophotometrical investigation of the NGC 3359 galaxy

    International Nuclear Information System (INIS)

    Burenkov, A.N.; Khchikyan, Eh.E.; AN Armyanskoj SSR, Byurakan. Astrofizicheskaya Observatoriya)

    1986-01-01

    Results of detailed spectrophotometrical investigations of NGC 3353, carried out with 6 m telescope of SAO Academy of Sciences of the USSR are presented (dispersion approximately 65 A/mm). Four separate condensations, the brightest of which is Mark 35, are studied. In the spectrum of Mark 35 the emission lines for Hsub(α) to H 12 , HeI lambda lambda 7065, 6678, 5876, 4922, 4472, 3820 and forbidden lines [01]lambda lambdas 6300/64, [02] lambda 3727, [03] lambda lambda 5007, 4959, 4363, [Ne3] lambda 3869, [N2] lambda lambda 6584/48, [S2] lambda lambda 6717/31, [S3] lambda 6310, [Ar3] lambda 7136 are detected. In the second central condensation, called ''nucleus'', emission lines are weaker and beginning with Hsub(β) the absorption components appear which become stronger in the late members of Balmer lines. The forbidden lines in the nucleus are strong: [Ne3], [O3], [O2], [S2][N2]. The relative intensities and equivalent widths of emission lines as well as the chemical composition of Mark 35 and ''nucleus'' are estimated. Both condensations according to their physical properties look like superassociations. It has been concluded that the source of excitation are young stars. NGC 3353 is probably the net of superassociations

  13. Reliability Engineering

    International Nuclear Information System (INIS)

    Lee, Sang Yong

    1992-07-01

    This book is about reliability engineering, which describes definition and importance of reliability, development of reliability engineering, failure rate and failure probability density function about types of it, CFR and index distribution, IFR and normal distribution and Weibull distribution, maintainability and movability, reliability test and reliability assumption in index distribution type, normal distribution type and Weibull distribution type, reliability sampling test, reliability of system, design of reliability and functionality failure analysis by FTA.

  14. Analysis of ionic channels by a flash spectrophotometric technique applicable to thylakoid membranes : CF0, the proton channel of the chloroplast ATP synthase, and, for comparison, gramicidin

    NARCIS (Netherlands)

    Lill, H.; Althoff, Gerd; Junge, Wolfgang

    We previously introduced a flash spectrophotometric method to analyze proton conduction by CF0 in vesicles derived from thylakoid membranes (H. Lill, S. Engelbrecht, G. Schönknecht & W. Junge, 1986, Eur. J. Biochem.160:627-634). The unit conductance of CF0, as revealed by this technique, was orders

  15. Power electronics reliability analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Mark A.; Atcitty, Stanley

    2009-12-01

    This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.

  16. Spectrophotometric Rapid-Response Classification of Near-Earth Objects

    Science.gov (United States)

    Mommert, Michael; Trilling, David; Butler, Nat; Axelrod, Tim; Moskovitz, Nick; Jedicke, Robert; Pichardo, Barbara; Reyes-Ruiz, Mauricio

    2015-08-01

    Small NEOs are, as a whole, poorly characterized, and we know nothing about the physical properties of the majority of all NEOs. The rate of NEO discoveries is increasing each year, and projects to determine the physical properties of NEOs are lagging behind. NEOs are faint, and generally even fainter by the time that follow-up characterizations can be made days or weeks after their discovery. There is a need for a high-throughput, high-efficiency physical characterization strategy in which hundreds of faint NEOs can be characterized each year. Broadband photometry in the near-infrared is sufficiently diagnostic to assign taxonomic types, and hence constrain both the individual and ensemble properties of NEOs.We present results from our rapid response near-infrared spectrophotometric characterization program of NEOs. We are using UKIRT (on Mauna Kea) and the RATIR instrument on the 1.5m telescope at the San Pedro Martir Observatory (Mexico) to allow us to make observations most nights of the year in robotic/queue mode. We derive taxonomic classifications for our targets using machine-learning techniques that are trained on a large sample of measured asteroid spectra. For each target we assign a probability for it to belong to a number of different taxa. Target selection, observation, data reduction, and analysis are highly automated, requiring only a minimum of user interaction, making this technique powerful and fast. Our targets are NEOs that are generally too faint for other characterization techniques, or would require many hours of large telescope time.

  17. Spectrophotometric Investigations of Macrolide Antibiotics: A Brief Review

    Directory of Open Access Journals (Sweden)

    Mrudul R. Keskar

    2015-01-01

    Full Text Available Macrolides, one of the most commonly used class of antibiotics, are a group of drugs produced by Streptomyces species. They belong to the polyketide class of natural products. Their activity is due to the presence of a large macrolide lactone ring with deoxy sugar moieties. They are protein synthesis inhibitors and broad-spectrum antibiotics, active against both gram-positive and gram-negative bacteria. Different analytical techniques have been reported for the determination of macrolides such as chromatographic methods, flow injection methods, spectrofluorometric methods, spectrophotometric methods, and capillary electrophoresis methods. Among these methods, spectrophotometric methods are sensitive and cost effective for the analysis of various antibiotics in pharmaceutical formulations as well as biological samples. This article reviews different spectrophotometric methods for the determination of macrolide antibiotics.

  18. The thermodynamic dissociation constants of losartan, paracetamol, phenylephrine and quinine by the regression analysis of spectrophotometric data

    International Nuclear Information System (INIS)

    Meloun, Milan; Syrovy, Tomas; Vrana, Ales

    2005-01-01

    The mixed dissociation constants of four drug acids - losartan, paracetamol, phenylephrine and quinine - at various ionic strengths I of range 0.01 and 1.0 and at temperatures of 25 and 37 deg. C were determined using SPECFIT32 and SQUAD(84) regression analysis of the pH-spectrophotometric titration data. A proposed strategy of efficient experimentation in a dissociation constants determination, followed by a computational strategy for the chemical model with a dissociation constants determination, is presented on the protonation equilibria of losartan. Indices of precise methods predict the correct number of components, and even the presence of minor ones when the data quality is high and the instrumental error is known. Improved identification of the number of species uses the second or third derivative function for some indices, namely when the number of species in the mixture is higher than 3 and when, due to large variations in the indicator values even at logarithmic scale, the indicator curve does not reach an obvious point where the slope changes. The thermodynamic dissociation constant pKaT was estimated by nonlinear regression of {pK a , I} data at 25 and 37 deg. C: for losartan pKa,1T=3.63(1) and 3.57(3), pKa,2T=4.84(1) and 4.80(3), for paracetamol pKa,1T=9.78(1) and 9.65(1), for phenylephrine pKa,1T=9.17(1) and 8.95(1), pKa,2T=10.45(1) and 10.22(1), for quinine pKa,1T=4.25(1) and 4.12(1), pKa,2T=8.72(1) and 8.46(2). Goodness-of-fit tests for various regression diagnostics enabled the reliability of the parameter estimates to be found

  19. The thermodynamic dissociation constants of losartan, paracetamol, phenylephrine and quinine by the regression analysis of spectrophotometric data

    Energy Technology Data Exchange (ETDEWEB)

    Meloun, Milan [Department of Analytical Chemistry, University of Pardubice, 53210 Pardubice (Czech Republic)]. E-mail: milan.meloun@upce.cz; Syrovy, Tomas [Department of Analytical Chemistry, University of Pardubice, 53210 Pardubice (Czech Republic)]. E-mail: tomas.syrovy@upce.cz; Vrana, Ales [IVAX Pharmaceuticals, s.r.o. 74770 Opava (Czech Republic)]. E-mail: ales_vrana@ivax-cr.com

    2005-03-21

    The mixed dissociation constants of four drug acids - losartan, paracetamol, phenylephrine and quinine - at various ionic strengths I of range 0.01 and 1.0 and at temperatures of 25 and 37 deg. C were determined using SPECFIT32 and SQUAD(84) regression analysis of the pH-spectrophotometric titration data. A proposed strategy of efficient experimentation in a dissociation constants determination, followed by a computational strategy for the chemical model with a dissociation constants determination, is presented on the protonation equilibria of losartan. Indices of precise methods predict the correct number of components, and even the presence of minor ones when the data quality is high and the instrumental error is known. Improved identification of the number of species uses the second or third derivative function for some indices, namely when the number of species in the mixture is higher than 3 and when, due to large variations in the indicator values even at logarithmic scale, the indicator curve does not reach an obvious point where the slope changes. The thermodynamic dissociation constant pKaT was estimated by nonlinear regression of {l_brace}pK{sub a}, I{r_brace} data at 25 and 37 deg. C: for losartan pKa,1T=3.63(1) and 3.57(3), pKa,2T=4.84(1) and 4.80(3), for paracetamol pKa,1T=9.78(1) and 9.65(1), for phenylephrine pKa,1T=9.17(1) and 8.95(1), pKa,2T=10.45(1) and 10.22(1), for quinine pKa,1T=4.25(1) and 4.12(1), pKa,2T=8.72(1) and 8.46(2). Goodness-of-fit tests for various regression diagnostics enabled the reliability of the parameter estimates to be found.

  20. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    Science.gov (United States)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  1. Validation of HPLC and UV spectrophotometric methods for the determination of meropenem in pharmaceutical dosage form.

    Science.gov (United States)

    Mendez, Andreas S L; Steppe, Martin; Schapoval, Elfrides E S

    2003-12-04

    A high-performance liquid chromatographic method and a UV spectrophotometric method for the quantitative determination of meropenem, a highly active carbapenem antibiotic, in powder for injection were developed in present work. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by reversed-phase technique on an RP-18 column with a mobile phase composed of 30 mM monobasic phosphate buffer and acetonitrile (90:10; v/v), adjusted to pH 3.0 with orthophosphoric acid. The UV spectrophotometric method was performed at 298 nm. The samples were prepared in water and the stability of meropenem in aqueous solution at 4 and 25 degrees C was studied. The results were satisfactory with good stability after 24 h at 4 degrees C. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the two methods. The proposed methods are highly sensitive, precise and accurate and can be used for the reliable quantitation of meropenem in pharmaceutical dosage form.

  2. Different Spectrophotometric and Chromatographic Methods for Determination of Mepivacaine and Its Toxic Impurity.

    Science.gov (United States)

    Abdelwahab, Nada S; Fared, Nehal F; Elagawany, Mohamed; Abdelmomen, Esraa H

    2017-09-01

    Stability-indicating spectrophotometric, TLC-densitometric, and ultra-performance LC (UPLC) methods were developed for the determination of mepivacaine HCl (MEP) in the presence of its toxic impurity, 2,6-dimethylanaline (DMA). Different spectrophotometric methods were developed for the determination of MEP and DMA. In a dual-wavelength method combined with direct spectrophotometric measurement, the absorbance difference between 221.4 and 240 nm was used for MEP measurements, whereas the absorbance at 283 nm was used for measuring DMA in the binary mixture. In the second-derivative method, amplitudes at 272.2 and 232.6 nm were recorded and used for the determination of MEP and DMA, respectively. The developed TLC-densitometric method depended on chromatographic separation using silica gel 60 F254 TLC plates as a stationary phase and methanol-water-acetic acid (9 + 1 + 0.1, v/v/v) as a developing system, with UV scanning at 230 nm. The developed UPLC method depended on separation using a C18 column (250 × 4.6 mm id, 5 μm particle size) as a stationary phase and acetonitrile-water (40 + 60, v/v; pH 4 with phosphoric acid) as a mobile phase at a flow rate of 0.4 mL/min, with UV detection at 215 nm. The chromatographic run time was approximately 1 min. The proposed methods were validated with respect to International Conference on Harmonization guidelines regarding precision, accuracy, ruggedness, robustness, and specificity.

  3. 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.

  4. Simultaneous determination of a binary mixture of pantoprazole sodium and itopride hydrochloride by four spectrophotometric methods

    Science.gov (United States)

    Ramadan, Nesrin K.; El-Ragehy, Nariman A.; Ragab, Mona T.; El-Zeany, Badr A.

    2015-02-01

    Four simple, sensitive, accurate and precise spectrophotometric methods were developed for the simultaneous determination of a binary mixture containing Pantoprazole Sodium Sesquihydrate (PAN) and Itopride Hydrochloride (ITH). Method (A) is the derivative ratio method (1DD), method (B) is the mean centering of ratio spectra method (MCR), method (C) is the ratio difference method (RD) and method (D) is the isoabsorptive point coupled with third derivative method (3D). Linear correlation was obtained in range 8-44 μg/mL for PAN by the four proposed methods, 8-40 μg/mL for ITH by methods A, B and C and 10-40 μg/mL for ITH by method D. The suggested methods were validated according to ICH guidelines. The obtained results were statistically compared with those obtained by the official and a reported method for PAN and ITH, respectively, showing no significant difference with respect to accuracy and precision.

  5. Simultaneous determination of the brand new two-drug combination for the treatment of hepatitis C: Sofosbuvir/ledipasvir using smart spectrophotometric methods manipulating ratio spectra

    Science.gov (United States)

    Eissa, Maya S.

    2017-08-01

    In this work, various sensitive and selective spectrophotometric methods were first introduced for the simultaneous determination of sofosbuvir and ledipasvir in their binary mixture without preliminary separation. Ledipasvir was determined simply by zero-order spectrophotometric method at its λmax = 333.0 nm in a linear range of 2.5-30.0 μg/ml without any interference of sofosbuvir even in low or high concentrations and with mean percentage recovery of 100.05 ± 0.632. Sofosbuvir can be quantitatively estimated by one of the following smart spectrophotometric methods based on ratio spectra developed for the resolution of the overlapped spectra of their binary mixture; ratio difference spectrophotometric method (RD) by computing the difference between the amplitudes of sofosbuvir ratio spectra at 228 nm and 270 nm, first derivative (DD1) of ratio spectra by measuring the sum of amplitude of trough and peak at 265 nm and 277 nm, respectively, ratio subtraction (RS) spectrophotometric method in which sofosbuvir can be successfully determined at its λmax = 261.0 nm and mean centering (MC) of ratio spectra by measuring the mean centering values at 270 nm. All of the above mentioned spectrophotometric methods can estimate sofosbuvir in a linear range of 7.5-90.0 μg/ml with mean percentage recoveries of 100.57 ± 0.810, 99.92 ± 0.759, 99.51 ± 0.475 and 100.75 ± 0.672, respectively. These methods were successfully applied to the analysis of their combined dosage form and bulk powder. The adopted methods were also validated as per ICH guidelines and statistically compared to an in-house HPLC method.

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

    International Nuclear Information System (INIS)

    Pérez-González, Pablo G.; Cava, Antonio; Barro, Guillermo; Villar, Víctor; Cardiel, Nicolás; Espino, Néstor; Gallego, Jesús; Ferreras, Ignacio; Rodríguez-Espinosa, José Miguel; Balcells, Marc; Cepa, Jordi; Alonso-Herrero, Almudena; Cenarro, Javier; Charlot, Stéphane; Cimatti, Andrea; Conselice, Christopher J.; Daddi, Emmanuele; Elbaz, David; Donley, Jennifer; Gobat, R.

    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 2 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

  7. SHARDS: An Optical Spectro-photometric Survey of Distant Galaxies

    Science.gov (United States)

    Pérez-González, Pablo G.; Cava, Antonio; Barro, Guillermo; Villar, Víctor; Cardiel, Nicolás; Ferreras, Ignacio; Rodríguez-Espinosa, José Miguel; Alonso-Herrero, Almudena; Balcells, Marc; Cenarro, Javier; Cepa, Jordi; Charlot, Stéphane; Cimatti, Andrea; Conselice, Christopher J.; Daddi, Emmanuele; Donley, Jennifer; Elbaz, David; Espino, Néstor; Gallego, Jesús; Gobat, R.; González-Martín, Omaira; Guzmán, Rafael; Hernán-Caballero, Antonio; Muñoz-Tuñón, Casiana; Renzini, Alvio; Rodríguez-Zaurín, Javier; Tresse, Laurence; Trujillo, Ignacio; Zamorano, Jaime

    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 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 UV-to-MIR SEDs of the massive quiescent galaxies at z = 1.0-1.4 are well described by an exponentially decaying star formation history with scale τ = 100-200 Myr, age around 1.5-2.0 Gyr, solar or slightly sub-solar metallicity, and moderate extinction, A(V) ~ 0.5 mag. We also find that galaxies with masses above M* are typically older than lighter galaxies, as expected in a downsizing scenario of galaxy formation. This

  8. 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

  9. Determination of cyanide by a highly sensitive indirect spectrophotometric method.

    Science.gov (United States)

    Blanco, M; Maspoch, S

    1984-01-01

    Complexation of Pd(2+) with cyanide inhibits the extraction of the palladium complex of 5-phenylazo-8-aminoquinoline. This effect is used for the indirect spectrophotometric determination of cyanide at the mug level. Cyanide in industrial waste water and in sea-water is determined after distillation as HCN from the sample and collection in sodium hydroxide solution.

  10. Spectrophotometric determination of pizotefin maleate in pure form ...

    African Journals Online (AJOL)

    Two simple, quick and sensitive methods were described for the spectrophotometric determination of pizotefin maleate (PZT) either in pure form or pharmaceutical form (tablets). The methods were based on the reaction of pizotefin maleate as 'n' electron donor with chloranilic acid (p-CLA) and 7,7,8 ...

  11. NEW SPECTROPHOTOMETRIC METHOD WITH KMnO 4 FOR ...

    African Journals Online (AJOL)

    The new method, an instrument-based and simple experimental procedure involves the reaction of the hypochlorite with arsenious oxide (As2O3) (pH 6.5) followed by the coupled reaction of residual As2O3 with permanganate at acidic pH. A titration procedure is described and spectrophotometric method is designed using ...

  12. Spectrophotometric and theoretical studies on the determination of ...

    African Journals Online (AJOL)

    Purpose: To develop a simple and cost effective spectrophotometric method for the ... species exhibited absorption maxima at 410 and 479 nm for the two systems in ... etilefrine in plasma and urine in pharmacokinetic ... In this work, the interactions of ET with BCG and ... prepared where the total volume of investigated.

  13. A Spectrophotometric Method for the Determination of Ramipril in ...

    African Journals Online (AJOL)

    A Spectrophotometric Method for the Determination of Ramipril in Solid Dosage Forms. ... Tropical Journal of Pharmaceutical Research ... Methods: UV spectrophotometry was used to develop and validate a simple method for the assay of ramipril in solid dosage form at λmax of 210 nm, as per International Conference on ...

  14. Eliminating amino acid interference during spectrophotometric NH4+ analysis

    NARCIS (Netherlands)

    Ros, G.H.; Leeuwen, van A.G.; Temminghoff, E.J.M.

    2011-01-01

    Amino acids can interfere with NH4+ in spectrophotometric NH4+ determination hampering accurate quantification of the fate of NH4+ and dissolved organic N in soils. Serious interference has been reported for soils rich in organic matter, and for soils that have been fumigated, oven-dried or

  15. Spectrophotometric determination of aluminium in steel with xylenol orange

    International Nuclear Information System (INIS)

    Majeed, A.; Javed, N.; Khan, M.S.

    1996-01-01

    Spectrophotometric determination of Aluminium in steel based on colour reaction between Aluminium and xylenol orange has been carried out. Red coloured complex formed in weak acidic solution is measured for its absorbance at 550 nm. The various optimum experimental conditions for Aluminium xylenol orange (Al-Xo) complex have been studied. (author)

  16. Spectrophotometric Determination of Cilostazol in Tablet Dosage Form

    African Journals Online (AJOL)

    Purpose: To develop simple, rapid and selective spectrophotometric methods for the determination of cilostazol in tablet dosage form. Methods: Cilostazol was dissolved in 50 % methanol and its absorbance was scanned by ultraviolet (UV) spectrophotometry. Both linear regression equation and standard absorptivity were ...

  17. Simultaneous determination of rifampicin, isoniazid and pyrazinamide in tablet preparations by multivariate spectrophotometric calibration.

    Science.gov (United States)

    Goicoechea, H C; Olivieri, A C

    1999-08-01

    The use of multivariate spectrophotometric calibration is presented for the simultaneous determination of the active components of tablets used in the treatment of pulmonary tuberculosis. The resolution of ternary mixtures of rifampicin, isoniazid and pyrazinamide has been accomplished by using partial least squares (PLS-1) regression analysis. Although the components show an important degree of spectral overlap, they have been simultaneously determined with high accuracy and precision, rapidly and with no need of nonaqueous solvents for dissolving the samples. No interference has been observed from the tablet excipients. A comparison is presented with the related multivariate method of classical least squares (CLS) analysis, which is shown to yield less reliable results due to the severe spectral overlap among the studied compounds. This is highlighted in the case of isoniazid, due to the small absorbances measured for this component.

  18. Validated univariate and multivariate spectrophotometric methods for the determination of pharmaceuticals mixture in complex wastewater

    Science.gov (United States)

    Riad, Safaa M.; Salem, Hesham; Elbalkiny, Heba T.; Khattab, Fatma I.

    2015-04-01

    Five, accurate, precise, and sensitive univariate and multivariate spectrophotometric methods were developed for the simultaneous determination of a ternary mixture containing Trimethoprim (TMP), Sulphamethoxazole (SMZ) and Oxytetracycline (OTC) in waste water samples collected from different cites either production wastewater or livestock wastewater after their solid phase extraction using OASIS HLB cartridges. In univariate methods OTC was determined at its λmax 355.7 nm (0D), while (TMP) and (SMZ) were determined by three different univariate methods. Method (A) is based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method followed by ratio difference method for determination of TMP and SMZ. Method (B) is successive derivative ratio technique (SDR). Method (C) is mean centering of the ratio spectra (MCR). The developed multivariate methods are principle component regression (PCR) and partial least squares (PLS). The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs. The obtained results are statistically compared with those obtained by the official methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

  19. A novel method for spectrophotometric determination of pregabalin in pure form and in capsules

    Directory of Open Access Journals (Sweden)

    Gaur Prateek

    2011-10-01

    Full Text Available Abstract Background Pregabalin, a γ-amino-n-butyric acid derivative, is an antiepileptic drug not yet official in any pharmacopeia and development of analytical procedures for this drug in bulk/formulation forms is a necessity. We herein, report a new, simple, extraction free, cost effective, sensitive and reproducible spectrophotometric method for the determination of the pregabalin. Results Pregabalin, as a primary amine was reacted with ninhydrin in phosphate buffer pH 7.4 to form blue violet colored chromogen which could be measured spectrophotometrically at λmax 402.6 nm. The method was validated with respect to linearity, accuracy, precision and robustness. The method showed linearity in a wide concentration range of 50-1000 μg mL-1 with good correlation coefficient (0.992. The limits of assays detection was found to be 6.0 μg mL-1 and quantitation limit was 20.0 μg mL-1. The suggested method was applied to the determination of the drug in capsules. No interference could be observed from the additives in the capsules. The percentage recovery was found to be 100.43 ± 1.24. Conclusion The developed method was successfully validated and applied to the determination of pregabalin in bulk and pharmaceutical formulations without any interference from common excipients. Hence, this method can be potentially useful for routine laboratory analysis of pregabalin.

  20. Spectrophotometric measurement of calcium carbonate saturation states in seawater.

    Science.gov (United States)

    Easley, Regina A; Patsavas, Mark C; Byrne, Robert H; Liu, Xuewu; Feely, Richard A; Mathis, Jeremy T

    2013-02-05

    Measurements of ocean pH and carbonate ion concentrations in the North Pacific and Arctic Oceans were used to determine calcium carbonate saturation states (Ω(CaCO(3))) from spectrophotometric methods alone. Total carbonate ion concentrations, [CO(3)(2-)](T), were for the first time at sea directly measured using Pb(II) UV absorbance spectra. The basis of the method is given by the following: [formula see text] where (CO(3))β(1) is the PbCO(3)(0) formation constant, e(i) are molar absorptivity ratios, and R = (250)A/(234)A (ratio of absorbances measured at 250 and 234 nm). On the basis of shipboard and laboratory Pb(II) data and complementary carbon-system measurements, the experimental parameters were determined to be (25 °C) the following: [formula see text]. The resulting mean difference between the shipboard spectrophotometric and conventional determinations of [CO(3)(2-)](T) was ±2.03 μmol kg(-1). The shipboard analytical precision of the Pb(II) method was ∼1.71 μmol kg(-1) (2.28%). Spectrophotometric [CO(3)(2-)](T) and pH(T) were then combined to calculate Ω(CaCO(3)). For the case of aragonite, 95% of the spectrophotometric aragonite saturation states (Ω(Aspec)) were within ±0.06 of the conventionally calculated values (Ω(Acalc)) when 0.5 ≤ Ω(A) ≤ 2.0. When Ω(A) > 2.0, 95% of the Ω(Aspec) values were within ±0.18 of Ω(Acalc). Our shipboard experience indicates that spectrophotometric determinations of [CO(3)(2-)](T) and Ω(CaCO(3)) are straightforward, fast, and precise. The method yields high-quality measurements of two important, rapidly changing aspects of ocean chemistry and offers capabilities suitable for long-term automated in situ monitoring.

  1. Spectro-photometric calibration of the SuperNova Integral Field Spectrograph in the Nearby Supernova Factory collaboration framework

    International Nuclear Information System (INIS)

    Buton, Clement

    2009-01-01

    Ten years ago, type Ia supernovae used as distances indicators led to the discovery of the accelerating expansion of the universe. Today, a second generation of surveys has significantly increased the high-redshift type Ia supernovae sample. The low-redshift sample was however still limiting the cosmological analysis using SNe. In this framework, the Nearby Supernova Factory has followed 200 nearby type Ia supernovae using the dedicated Supernovae Integral Field Spectrograph with spectro-photometric capacities. My PhD thesis has been carried out at the Institut de Physique Nucleaire de Lyon and at the Lawrence Berkeley National Laboratory in the framework of the international cosmological project SNfactory. In order to reach the design spectrophotometric accuracy, attention has been focused on several key aspects of the calibration procedure, including: determination of a dedicated point spread function for 3D point source extraction, estimating the nightly photometric quality, derivation of the nightly sky extinction over the extended optical domain, its modeling in terms of physical components and its variability within a given night. A full multi-standards calibration pipeline has been implemented using approximately 4000 observations of spectrophotometric standard stars taken throughout the night over nearly 500 individual nights. Preliminary scientific results of the whole SNfactory collaboration will be presented at the end of this thesis. (author)

  2. The Development of DNA Based Methods for the Reliable and Efficient Identification of Nicotiana tabacum in Tobacco and Its Derived Products

    Directory of Open Access Journals (Sweden)

    Sukumar Biswas

    2016-01-01

    Full Text Available Reliable methods are needed to detect the presence of tobacco components in tobacco products to effectively control smuggling and classify tariff and excise in tobacco industry to control illegal tobacco trade. In this study, two sensitive and specific DNA based methods, one quantitative real-time PCR (qPCR assay and the other loop-mediated isothermal amplification (LAMP assay, were developed for the reliable and efficient detection of the presence of tobacco (Nicotiana tabacum in various tobacco samples and commodities. Both assays targeted the same sequence of the uridine 5′-monophosphate synthase (UMPS, and their specificities and sensitivities were determined with various plant materials. Both qPCR and LAMP methods were reliable and accurate in the rapid detection of tobacco components in various practical samples, including customs samples, reconstituted tobacco samples, and locally purchased cigarettes, showing high potential for their application in tobacco identification, particularly in the special cases where the morphology or chemical compositions of tobacco have been disrupted. Therefore, combining both methods would facilitate not only the detection of tobacco smuggling control, but also the detection of tariff classification and of excise.

  3. Validated Spectrophotometric Methods for Simultaneous Determination of Food Colorants and Sweeteners

    Directory of Open Access Journals (Sweden)

    Fatma Turak

    2013-01-01

    Full Text Available Two simple spectrophotometric methods have been proposed for simultaneous determination of two colorants (Indigotin and Brilliant Blue and two sweeteners (Acesulfame-K and Aspartame in synthetic mixtures and chewing gums without any prior separation or purification. The first method, derivative spectrophotometry (ZCDS, is based on recording the first derivative curves (for Indigotin, Brillant Blue, and Acesulfame-K and third-derivative curve (for Aspartame and determining each component using the zero-crossing technique. The other method, ratio derivative spectrophotometry (RDS, depends on application ratio spectra of first- and third-derivative spectrophotometry to resolve the interference due to spectral overlapping. Both colorants and sweeteners showed good linearity, with regression coefficients of 0.9992–0.9999. The LOD and LOQ values ranged from 0.05 to 0.33 μgmL−1 and from 0.06 to 0.47 μgmL−1, respectively. The intraday and interday precision tests produced good RSD% values (<0.81%; recoveries ranged from 99.78% to 100.67% for all two methods. The accuracy and precision of the methods have been determined, and the methods have been validated by analyzing synthetic mixtures containing colorants and sweeteners. Two methods were applied for the above combination, and satisfactory results were obtained. The results obtained by applying the ZCDS method were statistically compared with those obtained by the RDS method.

  4. Spectrophotometric determination of metformin in pharmaceutical preparations, serum and urine using benzoin as derivatizing reagent

    International Nuclear Information System (INIS)

    Alamgir, M.; Hayat, A.

    2014-01-01

    A simple and selective spectrophotometric procedure is described for the determination of Metformin based on derivatization with benzoin. The Beers law was obeyed with 2.50-12.50 meu mol L-1 at 290 nm with coefficient of determination (r2) 0.997. The experimental conditions in term of pH, reaction time and temperature, and addition of derivatizing reagent were examined. The pure metformin-benzoin derivative was prepared and characterized by FT-IR and mass spectroscopic techniques. The method was applied for the determination of metformin from pharmaceutical preparations and serum and urine of volunteers after spiking with metformin. The results were checked by standard addition method. A number of pharmaceutical additives and serum or urine matrix did not affect the determination of metformin. (author)

  5. Three different spectrophotometric methods manipulating ratio spectra for determination of binary mixture of Amlodipine and Atorvastatin

    Science.gov (United States)

    Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeiny, Badr A.

    2011-12-01

    Three simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed for the simultaneous determination of Amlodipine besylate (AM) and Atorvastatin calcium (AT) in tablet dosage forms. The first method is first derivative of the ratio spectra ( 1DD), the second is ratio subtraction and the third is the method of mean centering of ratio spectra. The calibration curve is linear over the concentration range of 3-40 and 8-32 μg/ml for AM and AT, 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. Standard deviation is <1.5 in the assay of raw materials and tablets. Methods are validated as per ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit.

  6. Software reliability

    CERN Document Server

    Bendell, A

    1986-01-01

    Software Reliability reviews some fundamental issues of software reliability as well as the techniques, models, and metrics used to predict the reliability of software. Topics covered include fault avoidance, fault removal, and fault tolerance, along with statistical methods for the objective assessment of predictive accuracy. Development cost models and life-cycle cost models are also discussed. This book is divided into eight sections and begins with a chapter on adaptive modeling used to predict software reliability, followed by a discussion on failure rate in software reliability growth mo

  7. 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.

  8. 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.

  9. Spectrophotometric and spectrofluorimetric methods for the determination of saxagliptin and vildagliptin in bulk and pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    Marwa S. Moneeb

    2013-12-01

    Full Text Available New simple and sensitive spectrophotometric and spectrofluorimetric methods have been developed and validated for the determination of saxagliptin (SAX and vildagliptin (VDG in bulk and pharmaceutical preparations. The spectrophotometric methods were based on derivatization of the investigated drugs with two reagents: 1,2-naphthoquinone-4-sulfonic acid sodium salt (NQS and 4-chloro-7-nitrobenzofurazan (NBD-Cl. For further increase in the sensitivity, the D1 spectra of the reactions products were also recorded. For NQS reaction, Beer’s law was obeyed over the ranges of 5–30 and 7–45 μg mL−1 for the absorbance readings; and 3–32 and 5–50 μg mL−1 for the derivative readings of SAX and VDG, respectively. For NBD-Cl reaction, Beer’s law was obeyed over the ranges of 3–20 and 4.5–35 μg mL−1 for the absorbance readings; and 1.5–25 and 2.5–40 μg mL−1 for the derivative readings of SAX and VDG, respectively. Spectrofluorimetric methods were developed based on the fact that the derivatized investigated drugs with NBD-Cl reagent are highly fluorescent products. The fluorescence concentration plots were linear over the ranges of 0.02–0.25 and 0.03–0.37 μg mL−1 for SAX and VDG, respectively. The fluorescence measurement enabled the detection of SAX and VDG at concentrations of about 3 and 7 ng mL−1, respectively. The proposed methods have been validated and successfully applied to the determination of the investigated drugs in their pharmaceutical preparations. The results obtained were statistically compared to those obtained from reference methods.

  10. Spectrophotometric determination of silica in water. Low range

    International Nuclear Information System (INIS)

    Acosta L, E.

    1992-07-01

    The spectrophotometric method for the determination of the silica element in water, demineralized water, raw waters, laundry waters, waters treated with ion exchange resins and sea waters is described. This method covers the determination of the silica element in the interval from 20 to 1000 μg/l on 50 ml. of base sample. These limits its can be variable if the size of the used aliquot one is changed for the final determination of the silica element. (Author)

  11. Spectrophotometric determination of thorium using arsenazo III in water

    International Nuclear Information System (INIS)

    Rio, M.A.P. do; Godoy, J.M. de.

    1985-01-01

    A spectrophotometric determination of thorium with arsenazo III (1,8 dihidroxynaphtaline - 3,6 sulfanic acid - 2,7 bis (azo-2) - phenil argonic acid) was carried out aiming to analyse this element in water. In order to eliminate possible interferences, a coprecipitation with lantanium fluoride was used followed by an extration with 0,2 M TTA (tenoil-trifluor - aceton) / Benzen. The results showed a good agreement with the ones obtained by alfa-spectrometry. (Author) [pt

  12. Spectrophotometric determination of procainamide hydrochloride using sodium periodate

    OpenAIRE

    Al-Tamrah, S.; Al-Abbad, S.

    2015-01-01

    A simple spectrophotometric method has been described for the determination of procainamide hydrochloride. The method is based on the oxidation of procainamide hydrochloride by sodium periodate in the presence of sulfuric acid and measurement of the absorbance of the violet color formed at 531 nm. Parameters affecting the reaction were studied and conditions were optimized. Linear calibration graph was obtained from 50 to 700 μg ml−1 of procainamide hydrochloride and the limit of detection wa...

  13. SPECTROPHOTOMETRIC ASSESSMENT OF FERRIC REDUCING POWER OF THE INSTANT COFFEE

    OpenAIRE

    Tsiupko, T. G.; Tishchenko, E. A.; Voronova, O. B.

    2016-01-01

    The methods of antioxidant activity determination of foodstuffs using different indicator systems were discussed. The investigation of ferric reducing power (FRP) of coffee and its individual phenolic components such as chlorogenic (CGA), caffeic (СА), ferulic (FA), gallic (GA), vanillic (VA), protocatechuic (PCA) and uric (UA) acids as well as quercetin (Qu) and catechol (C) using the spectrophotometric method with Fe(III) - o-Phen indicator system was carried out. It was shown that the sens...

  14. Facile and Sensitive Spectrophotometric Technique for the Determination of Carbofuran in its Formulations, Water and Grain Samples with Substituted Anilines

    Directory of Open Access Journals (Sweden)

    V. Harikishna

    2005-01-01

    Full Text Available Methods are described for the determination of carbofuran in its formulations, in water and grain samples by the diazotization coupling spectrophotometric technique, using substituted anilines such as 4-bromoaniline, 4-methylaniline and 4-aminobenzaldehyde as the coupling agents. The orange red colour formed with 4-bromoaniline shows maximum absorption at 478 nm, yellow colour obtained with 4-methylaniline have maximum absorption at 465 nm whereas a red colour derivative formed with 4-aminobenzaldehyde shows λmax at 472 nm. The methods could be successfully applied for the determination of carbofuran in its formulations, water and grain samples.

  15. Titrimetric and Spectrophotometric Determination of Metaprolol tartrate in Pharmaceuticals Using N-Bromosuccinimide

    Directory of Open Access Journals (Sweden)

    K. Basavaiah

    2007-01-01

    Full Text Available One titrimetric and two spectrophotometric methods are presented for the assay of metaprolol tartrate (MPT in bulk drug and in tablets. The methods employ N-bromosuccinimide (NBS as the oxidimetric reagent and two dyes, methyl orange and indigo carmine as spectrophotometric reagents. In titrimetry, an acidified solution of MPT is treated with a known excess amount of NBS and after a definite time, the unreacted oxidant is determined by iodometric back titration. Spectrophotometry involves adding a measured excess of NBS to MPT in acid medium followed by determination of residual NBS by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (Method A or indigo carmine and measuring the absorbance at 610 nm (Method B. In all the methods, the amount of NBS reacted corresponds to the amount of MPT. Reaction conditions have been optimized. Titrimetry allows the determination of 1 - 12 mg of MPT and the calculations are based on a 1: 4 (MPT: NBS reaction stoichiometry. In spectrophotometry, the measured absorbance is found to increase linearly with the concentration of MPT serving as basis for quantitation. The systems obey Beer’s law for 0.5 - 4.0 μg mL-1 and 1.25 - 10.0 μg mL-1 for method A and method B, respectively. The apparent absorptivities are calculated to 1.07 × 105 be and 4.22 × 104 L mol cm-1 for method A and method B, respectively. The methods developed were applied to the assay of MPT in commercial tablet formulations, and the results were compared statistically with those of a reference method. The accuracy and reliability of the methods were further ascertained by performing recovery tests via standard-addition method.

  16. Spectrophotometric high-precision seawater pH determination for use in underway measuring systems

    Directory of Open Access Journals (Sweden)

    S. Aßmann

    2011-10-01

    Full Text Available Autonomous sensors are required for a comprehensive documentation of the changes in the marine carbon system and thus to differentiate between its natural variability and anthropogenic impacts. Spectrophotometric determination of pH – a key variable of the seawater carbon system – is particularly suited to achieve precise and drift-free measurements. However, available spectrophotometric instruments are not suitable for integration into automated measurement systems (e.g. FerryBox since they do not meet the major requirements of reliability, stability, robustness and moderate cost. Here we report on the development and testing of a~new indicator-based pH sensor that meets all of these requirements. This sensor can withstand the rough conditions during long-term deployments on ships of opportunity and is applicable to the open ocean as well as to coastal waters with a complex matrix and highly variable conditions. The sensor uses a high resolution CCD spectrometer as detector connected via optical fibers to a custom-made cuvette designed to reduce the impact of air bubbles. The sample temperature can be precisely adjusted (25 °C ± 0.006 °C using computer-controlled power supplies and Peltier elements thus avoiding the widely used water bath. The overall setup achieves a measurement frequency of 1 min−1 with a precision of ±0.0007 pH units, an average offset of +0.0005 pH units to a reference system, and an offset of +0.0081 pH units to a certified standard buffer. Application of this sensor allows monitoring of seawater pH in autonomous underway systems, providing a key variable for characterization and understanding of the marine carbon system.

  17. Development and Validation of UV-Visible Spectrophotometric Methods for Simultaneous Estimation of Thiocolchicoside and Dexketoprofen in Bulk and Tablet Dosage Form

    OpenAIRE

    M. T. Harde; S. B. Jadhav; D. L. Dharam; P. D. Chaudhari

    2012-01-01

    Development and validation of two simple, accurate, precise and economical UV Spectrophotometric methods for simultaneous estimation of Thiocolchicoside and Dexketoprofen in bulk and in tablet dosage form. The methods employed were Method-1 Absorbance correction method and Method-2 First order derivative spectroscopic method. In method-1 Absorbance is measured at two wavelengths 370nm at which Dexketoprofen has no absorbance and 255nm at which both the drug have considerable absorbance. In me...

  18. Emodin (1,3,8-trihydroxy-6-methylanthraquinone): a spectrophotometric reagent for the determination of beryllium(II), magnesium(II) and calcium(II)

    International Nuclear Information System (INIS)

    Pal, T.; Jana, N.R.

    1993-01-01

    The individual determination of Be II , Mg II or Ca II by conventional spectrophotometry and simultaneous determination of Mg II and Ca II in mixtures by first-derivative spectrophotometry are possible at trace levels, using emodin (1,3,8-trihydroxy-6-methylanthraquinone) as spectrophotometric reagent. Interference from other metal species, application of these methods to rock samples and statistical analysis of the results are discussed. (author)

  19. Human reliability

    International Nuclear Information System (INIS)

    Embrey, D.E.

    1987-01-01

    Concepts and techniques of human reliability have been developed and are used mostly in probabilistic risk assessment. For this, the major application of human reliability assessment has been to identify the human errors which have a significant effect on the overall safety of the system and to quantify the probability of their occurrence. Some of the major issues within human reliability studies are reviewed and it is shown how these are applied to the assessment of human failures in systems. This is done under the following headings; models of human performance used in human reliability assessment, the nature of human error, classification of errors in man-machine systems, practical aspects, human reliability modelling in complex situations, quantification and examination of human reliability, judgement based approaches, holistic techniques and decision analytic approaches. (UK)

  20. Reliability Calculations

    DEFF Research Database (Denmark)

    Petersen, Kurt Erling

    1986-01-01

    Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety...... and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic...... approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very...

  1. Spectrophotometric determination of caffeine using polyaniline films

    International Nuclear Information System (INIS)

    Monlinong, Jason Paul C.; Portilla, Ma. Cristina B.; Agustin, Katrina Jane D.; Pascual, Cherrie B.

    2015-01-01

    Polyaniline (PANI) films were fabricated by chemical oxidative polymerization of aniline monomers using ammonium persulfate (APS). The effects of varying oxidant concentration, oxidant solvent and washing solution in the PANI film deposition were first evaluated. 0.250 M APS in 0.200 M HCl and 0.200 M aniline in 0.200 M HCl were used to produce the emeraldine PANI (green) films which were deposited onto commercially available acctate films. The fabricated PANI film acts as an optical sensor baed on its redox-dependent switching of polyaniline from emeraldine (green) to pernigranilline (blue) form. The change in absorbance of blue PANI films immerse in caffeine-containing solution vs green fabricated PANI films were utilized in analysis of caffeine at 829 nm using a UV-VIS spectrophotometer. Repeatable results were obtained in intra-branch and inter-branch repeatability studies, with coefficient of variation (CV) values ranging rom 9.8-13.9% and 5.1-14.5%, respectively. Linear response was obtained over the concentration of 10.0-50.0 μg/mL. The limit of detection (LOD) and limit of quantitation (LOQ) were determined to be 2.5 and 8.5μg/mL, respectively. The obtained % recovery values of caffeine spiked in aqueous solution ranged from 84.9-107%. Three pharmaceutical formulations containing 20.0 or 25.0 μg/Ml caffeine where analyzed using PANI films by external calibration method. The obtained average caffeine values were 25.2 mg/tablet, 22.4 mg/tablet and 15.4 mg/capsule for Fevadol®, Fevergan® and Alaxan®FR, respectively. These values were 77.0% to 101% of the label claims. Human urine samples spiked with caffeine were also analyzed, after sample pre-treatment. Obtained percent recovery values ranged from 79.1 to 105%. This method demonstrated the potential of laboratory-fabricated PANI films as a low-cost rapid, reliable, simple and accurate method for caffeine quantification in pharmaceutical and clinical specimens. (author)

  2. Reliable and inexpensive expression of large, tagged, exogenous proteins in murine bone marrow-derived macrophages using a second generation lentiviral system

    Directory of Open Access Journals (Sweden)

    Matthew R. Miller

    2015-08-01

    Full Text Available Over the past two decades, researchers have struggled to efficiently express foreign DNA in primary macrophages, impeding research progress. The applications of lipofection, electroporation, microinjection, and viral-mediated transfer typically result in disruptions in macrophage differentiation and function, low expression levels of exogenous proteins, limited efficiency and high cell mortality. In this report, after extensive optimization, we present a method of expressing large tagged proteins at high efficiency, consistency, and low cost using lentiviral infection. This method utilizes laboratory-propagated second generation plasmids to produce efficient virus that can be stored for later use. The expression of proteins up to 150 kDa in size is achieved in 30–70% of cells while maintaining normal macrophage differentiation and morphology as determined by fluorescence microscopy and Western blot analysis. This manuscript delineates the reagents and methods used to produce lentivirus to express exogenous DNA in murine bone marrow-derived macrophages sufficient for single cell microscopy as well as functional assays requiring large numbers of murine bone marrow-derived macrophages.

  3. Derivation of Reliable Geometries in QM Calculations of DNA Structures: Explicit Solvent QM/MM and Restrained Implicit Solvent QM Optimizations of G-Quadruplexes.

    Science.gov (United States)

    Gkionis, Konstantinos; Kruse, Holger; Šponer, Jiří

    2016-04-12

    Modern dispersion-corrected DFT methods have made it possible to perform reliable QM studies on complete nucleic acid (NA) building blocks having hundreds of atoms. Such calculations, although still limited to investigations of potential energy surfaces, enhance the portfolio of computational methods applicable to NAs and offer considerably more accurate intrinsic descriptions of NAs than standard MM. However, in practice such calculations are hampered by the use of implicit solvent environments and truncation of the systems. Conventional QM optimizations are spoiled by spurious intramolecular interactions and severe structural deformations. Here we compare two approaches designed to suppress such artifacts: partially restrained continuum solvent QM and explicit solvent QM/MM optimizations. We report geometry relaxations of a set of diverse double-quartet guanine quadruplex (GQ) DNA stems. Both methods provide neat structures without major artifacts. However, each one also has distinct weaknesses. In restrained optimizations, all errors in the target geometries (i.e., low-resolution X-ray and NMR structures) are transferred to the optimized geometries. In QM/MM, the initial solvent configuration causes some heterogeneity in the geometries. Nevertheless, both approaches represent a decisive step forward compared to conventional optimizations. We refine earlier computations that revealed sizable differences in the relative energies of GQ stems computed with AMBER MM and QM. We also explore the dependence of the QM/MM results on the applied computational protocol.

  4. Co3O4 based non-enzymatic glucose sensor with high sensitivity and reliable stability derived from hollow hierarchical architecture

    Science.gov (United States)

    Tian, Liangliang; He, Gege; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Yang, Cong; Chen, Yanling; Li, Lu

    2018-02-01

    Inspired by kinetics, the design of hollow hierarchical electrocatalysts through large-scale integration of building blocks is recognized as an effective approach to the achievement of superior electrocatalytic performance. In this work, a hollow, hierarchical Co3O4 architecture (Co3O4 HHA) was constructed using a coordinated etching and precipitation (CEP) method followed by calcination. The resulting Co3O4 HHA electrode exhibited excellent electrocatalytic activity in terms of high sensitivity (839.3 μA mM-1 cm-2) and reliable stability in glucose detection. The high sensitivity could be attributed to the large specific surface area (SSA), ample unimpeded penetration diffusion paths and high electron transfer rate originating from the unique two-dimensional (2D) sheet-like character and hollow porous architecture. The hollow hierarchical structure also affords sufficient interspace for accommodation of volume change and structural strain, resulting in enhanced stability. The results indicate that Co3O4 HHA could have potential for application in the design of non-enzymatic glucose sensors, and that the construction of hollow hierarchical architecture provides an efficient way to design highly active, stable electrocatalysts.

  5. Reliability Engineering

    CERN Document Server

    Lazzaroni, Massimo

    2012-01-01

    This book gives a practical guide for designers and users in Information and Communication Technology context. In particular, in the first Section, the definition of the fundamental terms according to the international standards are given. Then, some theoretical concepts and reliability models are presented in Chapters 2 and 3: the aim is to evaluate performance for components and systems and reliability growth. Chapter 4, by introducing the laboratory tests, puts in evidence the reliability concept from the experimental point of view. In ICT context, the failure rate for a given system can be

  6. Reliability training

    Science.gov (United States)

    Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Dillard, Richard B.; Wong, Kam L.; Barber, Frank J.; Barina, Frank J.

    1992-01-01

    Discussed here is failure physics, the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low cost reliable products. A review of reliability for the years 1940 to 2000 is given. Next, a review of mathematics is given as well as a description of what elements contribute to product failures. Basic reliability theory and the disciplines that allow us to control and eliminate failures are elucidated.

  7. Spectrophotometric determination of volautile inorganic hydrides in binary gaseous mixtures

    International Nuclear Information System (INIS)

    Rezchikov, V.G.; Skachkova, I.N.; Kuznetsova, T.S.; Khrushcheva, V.V.

    1985-01-01

    A study was made on possibility of single and continuons analysis of binary mixtures (hydride-gas) for the content of volatile inorganic hydrides (VIH) from absorption spectra in the 185-280 nm band. Dependences of the percentage of VIH transmission on the wavelength are presented. It is shown that the maximum of their absorption depends on the element-hydrogen the bond length and binding energy. Detection limit for boron hydride was established to be n x 10 -3 % vol at 185-190 nm wavelength. Technique for spectrophotometric hydride determination in binary mixtures with hydrogen, argon, helium was developed. The technique provides the continuous control of gaseous mixture composition

  8. Spectrophotometric Determination of Thorium in Low Grade Minerals and Ores

    Energy Technology Data Exchange (ETDEWEB)

    Arnfelt, A L; Edmundsson, I

    1960-08-15

    The following method is intended for the determination of microgram quantities of thorium in samples of minerals and ores. The mineral sample is decomposed by repeated sintering with sodium peroxide. After digestion with water thorium peroxide hydrate is recovered by centrifugation and dissolved in hydrochloric acid. Thorium is determined spectrophotometrically with naphtarson after its separation from metals forming chloro complexes which are adsorbed on a strongly basic anion exchange resin. Interferences from a few different ions have been studied. The time required for the analysis of one sample is about 4 hours, when analysing 12 samples simultaneously

  9. Spectrophotometric determination of the first hydrolysis constant of praseodymium (III)

    International Nuclear Information System (INIS)

    Gonzalez M, R.; Lopez G, H.; Rojas H, A.

    2010-01-01

    The behavior of the trivalent ion praseodymium in 2 M of NaCl at 303 K and in CO 2 free conditions, was studied. Spectrophotometric titrations of the soluble species were used, in order to obtain the value of the first hydrolysis constant of Pr(III). The data obtained were treated with both the program Squad and by a graphic method, respectively. The result obtained using Squad was log*β 1 = -8.94 ± 0.03, while it was log*β 1 = -8.77 ± 0.03, when calculated graphically. These results are similar to the value obtained previously with the potentiometric method. (Author)

  10. Spectrophotometric determination of procainamide hydrochloride using sodium periodate

    Directory of Open Access Journals (Sweden)

    S. Al-Tamrah

    2015-09-01

    Full Text Available A simple spectrophotometric method has been described for the determination of procainamide hydrochloride. The method is based on the oxidation of procainamide hydrochloride by sodium periodate in the presence of sulfuric acid and measurement of the absorbance of the violet color formed at 531 nm. Parameters affecting the reaction were studied and conditions were optimized. Linear calibration graph was obtained from 50 to 700 μg ml−1 of procainamide hydrochloride and the limit of detection was 25 μg ml−1. The method was successfully applied for the determination of procainamide hydrochloride in pharmaceutical preparation.

  11. Spectrophotometric Determination of Thorium in Low Grade Minerals and Ores

    International Nuclear Information System (INIS)

    Arnfelt, A.L.; Edmundsson, I.

    1960-08-01

    The following method is intended for the determination of microgram quantities of thorium in samples of minerals and ores. The mineral sample is decomposed by repeated sintering with sodium peroxide. After digestion with water thorium peroxide hydrate is recovered by centrifugation and dissolved in hydrochloric acid. Thorium is determined spectrophotometrically with naphtarson after its separation from metals forming chloro complexes which are adsorbed on a strongly basic anion exchange resin. Interferences from a few different ions have been studied. The time required for the analysis of one sample is about 4 hours, when analysing 12 samples simultaneously

  12. Spectrophotometric determination of fluorides in water with Hach equipment

    International Nuclear Information System (INIS)

    Acosta L, E.

    1994-11-01

    The spectrophotometric method for the determination of the fluoride ion in water, demineralized water, raw waters, laundry waters and waters treated with ion exchange resins , using the technique and the SPADNS coloring indicated in the operation manual of the Hach equipment is described. This method covers the determination of the fluoride ion in the range from 0 to 2 mg/l on 25 ml. of radioactive base sample. These limits can be variable if the size of the used aliquot one is changed for the final determination of the fluoride ion. (Author)

  13. Simple Sensitive Spectrophotometric Determination of Vanadium in Biological and Environmental Samples

    Directory of Open Access Journals (Sweden)

    B. Krishna Priya

    2006-01-01

    Full Text Available Novel, rapid, highly sensitive and selective spectrophotometric method for the determination of traces of vanadium (V in environmental and biological samples, pharmaceutical and steel samples was studied. The method is based on oxidation of 2,4- dinitro phenyl hydrazine(2,4-DNPH by vanadium (V followed by coupling reaction with N-(1-naphthalene-1-ylethane-1,2-diamine-dihydrochloride (NEDA in acidic medium to give red colored derivative or on oxidation of 4-Amino Pyridine by vanadium (V followed by coupling reaction with NEDA in basic medium to give pink colored derivative. The red colored derivative having an λmax 495 nm which is stable for 8 days and the pink colored derivative with 525 nm is stable for more than 7 days at 350C. Beer's law is obeyed for vanadium (V in the concentration range of 0.02 - 3.5 μg mL–1 (red derivative and 0.03 – 4.5 μg mL–1 (pink derivative at the wave length of maximum absorption. The optimum reaction conditions and other analytical parameters were investigated to enhance the sensitivity of the present method. The detailed study of various interferences made the method more selective. The proposed method was successfully applied to the analysis of vanadium in natural water samples, plant material, soil samples, synthetic mixtures, pharmaceutical samples and biological samples. The results obtained were agreed with the reported methods at the 95 % confidence level. The performance of proposed method was evaluated in terms of Student's t-test and Variance ratio f-test which indicates the significance of proposed method over reported method.

  14. Reliability calculations

    International Nuclear Information System (INIS)

    Petersen, K.E.

    1986-03-01

    Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very complex systems. In order to increase the applicability of the programs variance reduction techniques can be applied to speed up the calculation process. Variance reduction techniques have been studied and procedures for implementation of importance sampling are suggested. (author)

  15. Systems reliability/structural reliability

    International Nuclear Information System (INIS)

    Green, A.E.

    1980-01-01

    The question of reliability technology using quantified techniques is considered for systems and structures. Systems reliability analysis has progressed to a viable and proven methodology whereas this has yet to be fully achieved for large scale structures. Structural loading variants over the half-time of the plant are considered to be more difficult to analyse than for systems, even though a relatively crude model may be a necessary starting point. Various reliability characteristics and environmental conditions are considered which enter this problem. The rare event situation is briefly mentioned together with aspects of proof testing and normal and upset loading conditions. (orig.)

  16. 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.

  17. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

    Science.gov (United States)

    Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-01-01

    Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  18. Flame Spectrophotometric Determination of Strontium in Water and Biological Material

    Energy Technology Data Exchange (ETDEWEB)

    Joensson, G

    1964-10-15

    A flame spectrophotometric method has been developed for the determination of strontium in biological material and water samples. Strontium is determined in the presence of calcium at a wavelength of 4607 A. The intensity of the strontium emission from the sample is increased if n-butanol is added to a solution of the sample in water. With a 6 vol% solution of n-butanol in water, an optimum intensity of 3.5 times that obtained with pure water solution is obtained. Anions and alkali metals which might interfere with the flame spectrophotometric determination are separated from the sample by a simple ion exchange operation. The method allows determination of strontium in solutions down to 0.1{mu}g/ml. In this case the standard deviation is 3.1 % and with a strontium concentration of 1 {mu}g/ml the deviation is 0.9 %. This method has been used for the determination of strontium in samples of varying composition such as bone, meat and skin from fishes, samples of human bones, shell-fish, milk, and water, in which case Sr quantities of 5{mu}g were determined with an analytical error of less than 5 % and Sr{sub q}uantities greater than 10 {mu}g with an error of less than 3 %.

  19. 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.

  20. AAS and spectrophotometric determination of propranolol HCl and metoprolol tartrate.

    Science.gov (United States)

    El-Ries, M A; Abou Attia, F M; Ibrahim, S A

    2000-12-15

    Two simple and accurate spectrophotometric methods are described for the determination of propranolol hydrochloride (I) and metoprolol tartrate (II). The methods are based on the reaction of each drug as a secondary amine: (a) with carbon disulphide, the formed complex extracted into iso-butyl methyl ketone (IBMK) after chelation with Cu(II) ions at pH 7.5, followed by measuring the absorbance at 435.4 nm or indirectly for the drug by flame atomic absorption spectrophotometry (AAS). The calibration graph is linear up to 40 and 60 microg ml(-1) with apparent molar absorptivities of 6.89 x 10(3) and 1.08 x 104 l mol(-1) cm(-1) and correlation coefficients of 0.9994 and 0.9995 for propranolol and metoprolol, respectively; (b) with pi-acceptors, tetracyanoethylene (TCNE), or chloranilic acid (CLA) to give highly coloured complex species. The coloured products are quantitated spectrophotometrically at 415 or 510 nm for the two drugs with TCNE and CLA, respectively, and obey Beer's Law with RSD less than 2.0. The methods were applied to the determination of these drugs in pharmaceutical preparation without interferences.

  1. Flame Spectrophotometric Determination of Strontium in Water and Biological Material

    International Nuclear Information System (INIS)

    Joensson, G.

    1964-10-01

    A flame spectrophotometric method has been developed for the determination of strontium in biological material and water samples. Strontium is determined in the presence of calcium at a wavelength of 4607 A. The intensity of the strontium emission from the sample is increased if n-butanol is added to a solution of the sample in water. With a 6 vol% solution of n-butanol in water, an optimum intensity of 3.5 times that obtained with pure water solution is obtained. Anions and alkali metals which might interfere with the flame spectrophotometric determination are separated from the sample by a simple ion exchange operation. The method allows determination of strontium in solutions down to 0.1μg/ml. In this case the standard deviation is 3.1 % and with a strontium concentration of 1 μg/ml the deviation is 0.9 %. This method has been used for the determination of strontium in samples of varying composition such as bone, meat and skin from fishes, samples of human bones, shell-fish, milk, and water, in which case Sr quantities of 5μg were determined with an analytical error of less than 5 % and Sr q uantities greater than 10 μg with an error of less than 3 %

  2. Convenience versus Biological Significance: Are PMA-Differentiated THP-1 Cells a Reliable Substitute for Blood-Derived Macrophages When Studying in Vitro Polarization?

    Science.gov (United States)

    Tedesco, Serena; De Majo, Federica; Kim, Jieun; Trenti, Annalisa; Trevisi, Lucia; Fadini, Gian Paolo; Bolego, Chiara; Zandstra, Peter W; Cignarella, Andrea; Vitiello, Libero

    2018-01-01

    Human peripheral-blood monocytes are used as an established in vitro system for generating macrophages. For several reasons, monocytic cell lines such as THP-1 have been considered as a possible alternative. In view of their distinct developmental origins and phenotypic attributes, we set out to assess the extent to which human monocyte-derived macrophages (MDMs) and phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 cells were overlapping across a variety of responses to activating stimuli. Resting (M0) macrophages were polarized toward M1 or M2 phenotypes by 48-h incubation with LPS (1 μg/ml) and IFN-γ (10 ng/ml) or with IL-4 (20 ng/ml) and IL-13 (5 ng/ml), respectively. At the end of stimulation, MDMs displayed more pronounced changes in marker gene expression than THP-1. Upon assaying an array of 41 cytokines, chemokines and growth factors in conditioned media (CM) using the Luminex technology, secretion of 29 out of the 41 proteins was affected by polarized activation. While in 12 of them THP-1 and MDM showed comparable trends, for the remaining 17 proteins their responses to activating stimuli did markedly differ. Quantitative comparison for selected analytes confirmed this pattern. In terms of phenotypic activation markers, measured by flow cytometry, M1 response was similar but the established MDM M2 marker CD163 was undetectable in THP-1 cells. In a beads-based assay, MDM activation did not induce significant changes, whereas M2 activation of THP-1 decreased phagocytic activity compared to M0 and M1. In further biological activity tests, both MDM and THP-1 CM failed to affect proliferation of mouse myogenic progenitors, whereas they both reduced adipogenic differentiation of mouse fibro-adipogenic progenitor cells (M2 to a lesser extent than M1 and M0). Finally, migration of human umbilical vein endothelial cells was enhanced by CM irrespective of cell type and activation state except for M0 CM from MDMs. In summary, PMA-differentiated THP-1

  3. Human reliability

    International Nuclear Information System (INIS)

    Bubb, H.

    1992-01-01

    This book resulted from the activity of Task Force 4.2 - 'Human Reliability'. This group was established on February 27th, 1986, at the plenary meeting of the Technical Reliability Committee of VDI, within the framework of the joint committee of VDI on industrial systems technology - GIS. It is composed of representatives of industry, representatives of research institutes, of technical control boards and universities, whose job it is to study how man fits into the technical side of the world of work and to optimize this interaction. In a total of 17 sessions, information from the part of ergonomy dealing with human reliability in using technical systems at work was exchanged, and different methods for its evaluation were examined and analyzed. The outcome of this work was systematized and compiled in this book. (orig.) [de

  4. Microelectronics Reliability

    Science.gov (United States)

    2017-01-17

    inverters  connected in a chain. ................................................. 5  Figure 3  Typical graph showing frequency versus square root of...developing an experimental  reliability estimating methodology that could both illuminate the  lifetime  reliability of advanced devices,  circuits and...or  FIT of the device. In other words an accurate estimate of the device  lifetime  was found and thus the  reliability  that  can  be  conveniently

  5. Different spectrophotometric methods applied for the analysis of simeprevir in the presence of its oxidative degradation product: Acomparative study

    Science.gov (United States)

    Attia, Khalid A. M.; El-Abasawi, Nasr M.; El-Olemy, Ahmed; Serag, Ahmed

    2018-02-01

    Five simple spectrophotometric methods were developed for the determination of simeprevir in the presence of its oxidative degradation product namely, ratio difference, mean centering, derivative ratio using the Savitsky-Golay filters, second derivative and continuous wavelet transform. These methods are linear in the range of 2.5-40 μg/mL and validated according to the ICH guidelines. The obtained results of accuracy, repeatability and precision were found to be within the acceptable limits. The specificity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. Furthermore, these methods were statistically comparable to RP-HPLC method and good results were obtained. So, they can be used for the routine analysis of simeprevir in quality-control laboratories.

  6. The value of service reliability

    OpenAIRE

    Benezech , Vincent; Coulombel , Nicolas

    2013-01-01

    International audience; This paper studies the impact of service frequency and reliability on the choice of departure time and the travel cost of transit users. When the user has (α, β, γ) scheduling preferences, we show that the optimal head start decreases with service reliability, as expected. It does not necessarily decrease with service frequency, however. We derive the value of service headway (VoSH) and the value of service reliability (VoSR), which measure the marginal effect on the e...

  7. Development and Statistical Validation of Spectrophotometric Methods for the Estimation of Nabumetone in Tablet Dosage Form

    Directory of Open Access Journals (Sweden)

    A. R. Rote

    2010-01-01

    Full Text Available Three new simple, economic spectrophotometric methods were developed and validated for the estimation of nabumetone in bulk and tablet dosage form. First method includes determination of nabumetone at absorption maxima 330 nm, second method applied was area under curve for analysis of nabumetone in the wavelength range of 326-334 nm and third method was First order derivative spectra with scaling factor 4. Beer law obeyed in the concentration range of 10-30 μg/mL for all three methods. The correlation coefficients were found to be 0.9997, 0.9998 and 0.9998 by absorption maxima, area under curve and first order derivative spectra. Results of analysis were validated statistically and by performing recovery studies. The mean percent recoveries were found satisfactory for all three methods. The developed methods were also compared statistically using one way ANOVA. The proposed methods have been successfully applied for the estimation of nabumetone in bulk and pharmaceutical tablet dosage form.

  8. Different Spectrophotometric Methods for Simultaneous Determination of Trelagliptin and Its Acid Degradation Product

    Science.gov (United States)

    Hassan, Mostafa A.; Zaghary, Wafaa A.

    2018-01-01

    New spectrophotometric and chemometric methods were carried out for the simultaneous assay of trelagliptin (TRG) and its acid degradation product (TAD) and applied successfully as a stability indicating assay to recently approved Zafatek® tablets. TAD was monitored using TLC to ensure complete degradation. Furthermore, HPLC was used to confirm dealing with one major acid degradation product. The proposed methods were developed by manipulating zero-order, first-derivative, and ratio spectra of TRG and TAD using simultaneous equation, first-derivative, and mean-centering methods, respectively. Using Spectra Manager II and Minitab v.14 software, the absorbance at 274 nm–260.4 nm, amplitudes at 260.4 nm–274.0 nm, and mean-centered values at 287.6 nm–257.2 nm were measured against methanol as a blank for TRG and TAD, respectively. Linearity and the other validation parameters were acceptable at concentration ranges of 5–50 μg/mL and 2.5–25 μg/mL for TRG and TAD, respectively. Using one-way analysis of variance (ANOVA), the optimized methods were compared and proved to be accurate for the simultaneous assay of TRG and TAD. PMID:29629213

  9. Validated spectrophotometric methods for simultaneous determination of troxerutin and carbazochrome in dosage form

    Science.gov (United States)

    Khattab, Fatma I.; Ramadan, Nesrin K.; Hegazy, Maha A.; Al-Ghobashy, Medhat A.; Ghoniem, Nermine S.

    2015-03-01

    Four simple, accurate, sensitive and precise spectrophotometric methods were developed and validated for simultaneous determination of Troxerutin (TXN) and Carbazochrome (CZM) in their bulk powders, laboratory prepared mixtures and pharmaceutical dosage forms. Method A is first derivative spectrophotometry (D1) where TXN and CZM were determined at 294 and 483.5 nm, respectively. Method B is first derivative of ratio spectra (DD1) where the peak amplitude at 248 for TXN and 439 nm for CZM were used for their determination. Method C is ratio subtraction (RS); in which TXN was determined at its λmax (352 nm) in the presence of CZM which was determined by D1 at 483.5 nm. While, method D is mean centering of the ratio spectra (MCR) in which the mean centered values at 300 nm and 340.0 nm were used for the two drugs in a respective order. The two compounds were simultaneously determined in the concentration ranges of 5.00-50.00 μg mL-1 and 0.5-10.0 μg mL-1 for TXN and CZM, respectively. The methods were validated according to the ICH guidelines and the results were statistically compared to the manufacturer's method.

  10. Benchmarking DFT and semi-empirical methods for a reliable and cost-efficient computational screening of benzofulvene derivatives as donor materials for small-molecule organic solar cells.

    Science.gov (United States)

    Tortorella, Sara; Talamo, Maurizio Mastropasqua; Cardone, Antonio; Pastore, Mariachiara; De Angelis, Filippo

    2016-02-24

    A systematic computational investigation on the optical properties of a group of novel benzofulvene derivatives (Martinelli 2014 Org. Lett. 16 3424-7), proposed as possible donor materials in small molecule organic photovoltaic (smOPV) devices, is presented. A benchmark evaluation against experimental results on the accuracy of different exchange and correlation functionals and semi-empirical methods in predicting both reliable ground state equilibrium geometries and electronic absorption spectra is carried out. The benchmark of the geometry optimization level indicated that the best agreement with x-ray data is achieved by using the B3LYP functional. Concerning the optical gap prediction, we found that, among the employed functionals, MPW1K provides the most accurate excitation energies over the entire set of benzofulvenes. Similarly reliable results were also obtained for range-separated hybrid functionals (CAM-B3LYP and wB97XD) and for global hybrid methods incorporating a large amount of non-local exchange (M06-2X and M06-HF). Density functional theory (DFT) hybrids with a moderate (about 20-30%) extent of Hartree-Fock exchange (HFexc) (PBE0, B3LYP and M06) were also found to deliver HOMO-LUMO energy gaps which compare well with the experimental absorption maxima, thus representing a valuable alternative for a prompt and predictive estimation of the optical gap. The possibility of using completely semi-empirical approaches (AM1/ZINDO) is also discussed.

  11. Benchmarking DFT and semi-empirical methods for a reliable and cost-efficient computational screening of benzofulvene derivatives as donor materials for small-molecule organic solar cells

    International Nuclear Information System (INIS)

    Tortorella, Sara; Talamo, Maurizio Mastropasqua; Cardone, Antonio; Pastore, Mariachiara; De Angelis, Filippo

    2016-01-01

    A systematic computational investigation on the optical properties of a group of novel benzofulvene derivatives (Martinelli 2014 Org. Lett. 16 3424–7), proposed as possible donor materials in small molecule organic photovoltaic (smOPV) devices, is presented. A benchmark evaluation against experimental results on the accuracy of different exchange and correlation functionals and semi-empirical methods in predicting both reliable ground state equilibrium geometries and electronic absorption spectra is carried out. The benchmark of the geometry optimization level indicated that the best agreement with x-ray data is achieved by using the B3LYP functional. Concerning the optical gap prediction, we found that, among the employed functionals, MPW1K provides the most accurate excitation energies over the entire set of benzofulvenes. Similarly reliable results were also obtained for range-separated hybrid functionals (CAM-B3LYP and wB97XD) and for global hybrid methods incorporating a large amount of non-local exchange (M06-2X and M06-HF). Density functional theory (DFT) hybrids with a moderate (about 20–30%) extent of Hartree–Fock exchange (HFexc) (PBE0, B3LYP and M06) were also found to deliver HOMO–LUMO energy gaps which compare well with the experimental absorption maxima, thus representing a valuable alternative for a prompt and predictive estimation of the optical gap. The possibility of using completely semi-empirical approaches (AM1/ZINDO) is also discussed. (paper)

  12. Sensitive and selective spectrophotometric determination of pantoprazole sodium in pharmaceuticals using permanganate

    Directory of Open Access Journals (Sweden)

    K. B. VINAY

    2010-03-01

    Full Text Available A simple visible spectrophotometric method is described for the determination of pantoprazole sodium sesquihydrate (PSS. The method is based on the formation of a brown colored product on treating PSS with permanganate in neutral medium, the absorbance being measured at 350 nm. The experimental conditions for the assay were optimized. The absorbance is found to increase linearly with the concentration of PSS and the calibration graph is linear in the range of 2.5-40.0 μg ml-1 with a linear regression coefficient of 0.998. The calculated molar absorptivity value is 1.27x104 l mol-1 cm-1 and the corresponding Sandel sensitivity is 0.0341 µg cm-2. The limits of detection (LOD and quantification (LOQ are calculated to be 0.49 and 1.47 µg ml-1, respectively. Intra-day and inter-day accuracy expressed as relative error were better than 2.0% and the corresponding precision (RSD was less than 2.5 %. The developed and validated method was applied to the determination of the active ingredient in a tablet dosage form and the results obtained agreed well with those of the reference method. The accuracy and reliability of the method were ascertained by performing recovery experiments via standard-addition procedure.

  13. Comparison of the acetyl bromide spectrophotometric method with other analytical lignin methods for determining lignin concentration in forage samples.

    Science.gov (United States)

    Fukushima, Romualdo S; Hatfield, Ronald D

    2004-06-16

    Present analytical methods to quantify lignin in herbaceous plants are not totally satisfactory. A spectrophotometric method, acetyl bromide soluble lignin (ABSL), has been employed to determine lignin concentration in a range of plant materials. In this work, lignin extracted with acidic dioxane was used to develop standard curves and to calculate the derived linear regression equation (slope equals absorptivity value or extinction coefficient) for determining the lignin concentration of respective cell wall samples. This procedure yielded lignin values that were different from those obtained with Klason lignin, acid detergent acid insoluble lignin, or permanganate lignin procedures. Correlations with in vitro dry matter or cell wall digestibility of samples were highest with data from the spectrophotometric technique. The ABSL method employing as standard lignin extracted with acidic dioxane has the potential to be employed as an analytical method to determine lignin concentration in a range of forage materials. It may be useful in developing a quick and easy method to predict in vitro digestibility on the basis of the total lignin content of a sample.

  14. A Unified tool to estimate Distances, Ages, and Masses (UniDAM) from spectrophotometric data

    Science.gov (United States)

    Mints, Alexey; Hekker, Saskia

    2017-08-01

    Context. Galactic archaeology, the study of the formation and evolution of the Milky Way by reconstructing its past from its current constituents, requires precise and accurate knowledge of stellar parameters for as many stars as possible. To achieve this, a number of large spectroscopic surveys have been undertaken and are still ongoing. Aims: So far consortia carrying out the different spectroscopic surveys have used different tools to determine stellar parameters of stars from their derived effective temperatures (Teff), surface gravities (log g), and metallicities ([Fe/H]); the parameters can be combined with photometric, astrometric, interferometric, or asteroseismic information. Here we aim to homogenise the stellar characterisation by applying a unified tool to a large set of publicly available spectrophotometric data. Methods: We used spectroscopic data from a variety of large surveys combined with infrared photometry from 2MASS and AllWISE and compared these in a Bayesian manner with PARSEC isochrones to derive probability density functions (PDFs) for stellar masses, ages, and distances. We treated PDFs of pre-helium-core burning, helium-core burning, and post helium-core burning solutions as well as different peaks in multimodal PDFs (I.e. each unimodal sub-PDF) of the different evolutionary phases separately. Results: For over 2.5 million stars we report mass, age, and distance estimates for each evolutionary phase and unimodal sub-PDF. We report Gaussian, skewed, Gaussian, truncated Gaussian, modified truncated exponential distribution or truncated Student's t-distribution functions to represent each sub-PDF, allowing us to reconstruct detailed PDFs. Comparisons with stellar parameter estimates from the literature show good agreement within uncertainties. Conclusions: We present UniDAM, the unified tool applicable to spectrophotometric data of different surveys, to obtain a homogenised set of stellar parameters. The unified tool and the tables with

  15. A new innovative spectrophotometric method for the simultaneous determination of sofosbuvir and ledipasvir

    Science.gov (United States)

    Mansour, Fotouh R.

    2018-01-01

    A new innovative spectrophotometric method is developed to determine the concentration ratios in binary mixtures by determining the zero crossing point in the first derivative of the gross curve. This relationship can be applied if the part of the UV spectrum of substance Y, that intersects with the overlaid spectra of substance X is straight. By plotting the intersection wavelength against the concentration ratio (Cx/Cy), a straight line was obtained with a co-efficient of determination equals 0.9999. As an application, simultaneous determination of sofosbuvir and ledipasvir in their binary mixtures was performed using two methods; a direct UV spectrophotometric method for determination of ledipasvir at 333 nm, and the new "wavelength-intersection ratio" method for determination of sofosbuvir. In the wavelength-intersection ratio method, different mixtures of sofosbuvir and ledipasvir containing different concentration ratios were prepared; the zero crossing point of the first derivative curve in the range 285 to 295 nm were determined for each mixture. An absorbance shift in the intersection was obtained with the change in the concentration ratio (sofosbuvir/ledipasvir). When the concentration ratio was plotted against the intersection wavelength, a straight line was obtained with a coefficient of determination of 0.9992. The direct method was linear in the range 3 to 18 μg/mL while the wavelength-intersection ratio method was linear in the range 11-110 μg/mL. The limits of detection were determined and found to be 0.5 and 3 μg/mL for ledipasvir and sofosbuvir, respectively. The accuracy and repeatability of the two methods were tested. The mean %recovery was found to be 100.19% and 100.75% for ledipasvir and sofosbuvir, respectively. The relative standard deviation was 0.57 for ledipasvir and 1.79 for sofosbuvir. The intermediate precision was also checked, the coefficients of variation for sofosbuvir and ledipasvir measurements between days did not exceed 1.88%.

  16. Liquid–liquid microextraction in a multicommuted flow system for direct spectrophotometric determination of iodine value in biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Andréia C.; Rocha, Fábio R.P., E-mail: frprocha@cena.usp.br

    2014-06-01

    Highlights: • First flow-based procedure for iodine value determination in biodiesel. • Simple, fast and reliable procedure. • Detection without sample pretreatment or phase separation. • Liquid–liquid microextraction with low sample and reagent volumes. • Avoid toxic reagents and organic solvent used in the reference procedure. Abstract: A flow-based procedure was developed for the direct spectrophotometric determination of the iodine value (IV) in biodiesel. The procedure was based on the microextraction/reaction of unsaturated compounds with triiodide ions in an aqueous medium by inserting the reagent solution between the aliquots of biodiesel without any pretreatment. The interaction occurred through the biodiesel film formed on the inner walls of the hydrophobic tube used as the reactor and at the aqueous/biodiesel interfaces. The spectrophotometric detection was based on the discoloration of the I₃⁻ reagent in the aqueous phase by using a glass tube coupled to a fiber-optic spectrophotometer as the detection cell. Reference solutions were prepared by dilution of biodiesel samples with previously determined IV in hexane. The analytical response was linear for IV from 13 to 135 g I₂/100 g with a detection limit of 5 g I₂/100 g. A coefficient of variation of 1.7% (n = 10) and a sampling rate of 108 determinations per hour were achieved by consuming 224 μL of the sample and 200 μg of I₂ per determination. The slopes of analytical curves obtained with three different biodiesel samples were in agreement (variations in slopes lower than 3.1%), thus indicating an absence of any matrix effects. Results for biodiesel samples from different sources agreed with the volumetric official procedure at the 95% confidence level. The proposed procedure is therefore a simple, fast, and reliable alternative for estimating the iodine value of biodiesel.

  17. Liquid–liquid microextraction in a multicommuted flow system for direct spectrophotometric determination of iodine value in biodiesel

    International Nuclear Information System (INIS)

    Pereira, Andréia C.; Rocha, Fábio R.P.

    2014-01-01

    Highlights: • First flow-based procedure for iodine value determination in biodiesel. • Simple, fast and reliable procedure. • Detection without sample pretreatment or phase separation. • Liquid–liquid microextraction with low sample and reagent volumes. • Avoid toxic reagents and organic solvent used in the reference procedure. - Abstract: A flow-based procedure was developed for the direct spectrophotometric determination of the iodine value (IV) in biodiesel. The procedure was based on the microextraction/reaction of unsaturated compounds with triiodide ions in an aqueous medium by inserting the reagent solution between the aliquots of biodiesel without any pretreatment. The interaction occurred through the biodiesel film formed on the inner walls of the hydrophobic tube used as the reactor and at the aqueous/biodiesel interfaces. The spectrophotometric detection was based on the discoloration of the I 3 − reagent in the aqueous phase by using a glass tube coupled to a fiber-optic spectrophotometer as the detection cell. Reference solutions were prepared by dilution of biodiesel samples with previously determined IV in hexane. The analytical response was linear for IV from 13 to 135 g I 2 /100 g with a detection limit of 5 g I 2 /100 g. A coefficient of variation of 1.7% (n = 10) and a sampling rate of 108 determinations per hour were achieved by consuming 224 μL of the sample and 200 μg of I 2 per determination. The slopes of analytical curves obtained with three different biodiesel samples were in agreement (variations in slopes lower than 3.1%), thus indicating an absence of any matrix effects. Results for biodiesel samples from different sources agreed with the volumetric official procedure at the 95% confidence level. The proposed procedure is therefore a simple, fast, and reliable alternative for estimating the iodine value of biodiesel

  18. Development and Validation of Eco-Friendly Liquid Chromatographic and Spectrophotometric Methods for Simultaneous Determination of Coformulated Drugs: Phenylephrine Hydrochloride and Prednisolone Acetate.

    Science.gov (United States)

    Mostafa, Nadia M; Elsayed, Ghada M; Hassan, Nagiba Y; El Mously, Dina A

    2017-11-01

    Five simple, sensitive, and eco-friendly LC and UV spectrophotometric methods have been developed for the simultaneous determination of phenylephrine hydrochloride (PHE) and prednisolone acetate (PRD) in their combined dosage form. The first method was reversed-phase (RP) LC using methanol-water-heptane-1-sulfonic acid sodium salt (75 + 25 + 0.1, v/v/w) as a mobile phase. Separation was achieved using an XSelect HSS reversed-phase C18 analytical column (250 × 4.6 mm, 5µm). The flow rate was 1.0 mL/min and UV detection was done at 230 nm. Quantification was achieved over the concentration ranges of 5-50 µg/mL for PHE and 2-90 µg/mL for PRD. Four spectrophotometric methods were proposed, namely dual wavelength, first derivative of ratio spectra, ratio difference, and mean-centering of ratio spectra. Linearity was observed in the concentration ranges of 10-120 and 5-35 µg/mL for PHE and PRD, respectively, for the spectrophotometric methods. Green solvents were used in the proposed methods because they play a vital role in the analytical methods' influence on the environment. The suggested methods were validated regarding linearity, accuracy, and precision according to the International Conference on Harmonization guidelines, with satisfactory results. These methods could be used as harmless substitutes for routine analysis of the mentioned drugs, with no interference from excipients.

  19. Redefining reliability

    International Nuclear Information System (INIS)

    Paulson, S.L.

    1995-01-01

    Want to buy some reliability? The question would have been unthinkable in some markets served by the natural gas business even a few years ago, but in the new gas marketplace, industrial, commercial and even some residential customers have the opportunity to choose from among an array of options about the kind of natural gas service they need--and are willing to pay for. The complexities of this brave new world of restructuring and competition have sent the industry scrambling to find ways to educate and inform its customers about the increased responsibility they will have in determining the level of gas reliability they choose. This article discusses the new options and the new responsibilities of customers, the needed for continuous education, and MidAmerican Energy Company's experiment in direct marketing of natural gas

  20. 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.

  1. An efficient absorbing system for spectrophotometric determination of nitrogen dioxide

    Science.gov (United States)

    Kaveeshwar, Rachana; Amlathe, Sulbha; Gupta, V. K.

    A simple and sensitive spectrophotometric method for determination of atmospheric nitrogen dioxide using o-nitroaniline as an efficient absorbing, as well as diazotizing, reagent is described. o-Nitroaniline present in the absorbing medium is diazotized by the absorbed nitrite ion to form diazonium compound. This is later coupled with 1-amino-2-naphthalene sulphonic acid (ANSA) in acidic medium to give red-violet-coloured dye,having λmax = 545 nm. The isoamyl extract of the red azo dye has λmax = 530 nm. The proposed reagents has ≈ 100% collection efficiency and the stoichiometric ratio of NO 2:NO 2- is 0.74. The other important analytical parameters have been investigated. By employing solvent extraction the sensitivity of the reaction was increased and up to 0.03 mg m -3 nitrogen dioxide could be estimated.

  2. 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.

  3. Spectrophotometric determination of the first hydrolysis constant of praseodymium (III)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez M, R.; Lopez G, H. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Rojas H, A., E-mail: hilario.lopez@inin.gob.m [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Departamento de Quimica, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2010-07-01

    The behavior of the trivalent ion praseodymium in 2 M of NaCl at 303 K and in CO{sub 2} free conditions, was studied. Spectrophotometric titrations of the soluble species were used, in order to obtain the value of the first hydrolysis constant of Pr(III). The data obtained were treated with both the program Squad and by a graphic method, respectively. The result obtained using Squad was log*{beta}{sub 1}= -8.94 {+-} 0.03, while it was log*{beta}{sub 1}= -8.77 {+-} 0.03, when calculated graphically. These results are similar to the value obtained previously with the potentiometric method. (Author)

  4. Spectrophotometric determination of the ASTM color of diesel oil

    Energy Technology Data Exchange (ETDEWEB)

    Douglas Willian Emanuel Alves Santana; Marcelle Prates Sepulveda; Paulo Jorge Sanches Barbeira

    2007-03-15

    One of the parameters analyzed to determine the quality of diesel oil is its ASTM color. Changes in color may be indicative of problems in the production process, contamination, degradation or the oxidation of diesel. The methodology recommended for determining the color of automotive diesel oil samples is the colorimetry according to standard ASTM D1500, in which a sample is introduced into a glass cell and the color of the sample is compared with an optical filter color scale. Although it is very simple, the manual method requires good visual acuity from the operator. This procedure becomes somewhat subjective in some cases since different operators can make distinct evaluations of the same sample. In this way, this work proposes the development of a spectrophotometric analysis methodology to eliminate the subjectiveness in the determination of ASTM color of diesel oil samples by using operator-independent parameters and making quality assay more accurate and precise. Short communication. 7 refs., 2 figs., 2 tabs.

  5. 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.

  6. Extractive Spectrophotometric Methods for the Determination of Etoricoxib in Tablets

    Directory of Open Access Journals (Sweden)

    Kamal Shah

    2009-01-01

    Full Text Available Two simple, rapid, sensitive, precise and economic spectrophotometric methods have been developed for the estimation of etoricoxib in tablet formulation. During the course of study, it was observed that acidic solution of the drug formed colored ion-association complexes with Bromocresol Green (BCG and Bromocresol Purple (BCP which were soluble in chloroform. This property of the drug was followed for the development of colorimetric methods for analysis of drug. The complex of etoricoxib with BCG and BCP showed λmax at 416 nm and 408 nm respectively. These methods were validated statistically. Recovery studies gave satisfactory results indicating that none of common additives and excipients interfere the assay method. The proposed methods are found to be simple, accurate and reproducible that was successfully applied for the analysis of tablet formulation.

  7. Spectrophotometric titration of sulfates in the presence of zirconium

    International Nuclear Information System (INIS)

    Kuznetsov, V.V.; Kotova, S.S.; Molokanova, L.G.; Chekmarev, A.M.; Yagodin, G.A.

    1978-01-01

    The procedure has been proposed for express determination of sulphate ions in the presence of zirconium by spectrophotometric titration with the use of barium chloride and nitrochromazo as an indicator. The procedure is based on bonding zirconium into a more stable complex with EDTA (ethylenediaminotetraacetic acid). The presence of excess of EDTA and zirconium (4) complexonate in the solution being titrated does not affect the titration curve shape and the character of break on the curve in the equivalence point. A complete demasking of SO 4 2- is observed in the case of 1O-fold excess of EDTA with respect to zirconium (4). Statistic evaluation of the method has shown that the results of titration can be distorted by chance errors only

  8. Extractive spectrophotometric determination of uranium with malachite green

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, S C; Nadkarni, M N [Bhabha Atomic Research Centre, Bombay (India). Fuel Reprocessing Div.

    1977-04-01

    A sensitive spectrophotometric method based on the extraction of a uranium-benzoate-Malachite Green complex by chlorobenzene is described. The absorption maximum is at 635 nm and the molar absorptivity is 8.3 x 10/sup 4/1. mole /sup -1/ cm/sup -1/. A preliminary separation of uranium by extraction with methyl isobutyl ketone from acid-deficient aluminium nitrate solution is used to avoid interferences. An aliquot of the extract in then diluted with chlorobenzene and shaken with benzoate buffer containing Malachite Green (MG). The method has been applied for the determination of uranium in a synthetic leach solution. The complex extracted is probably (U0/sub 2/(C/sub 6/H/sub 5/C00/sub 3//sup -/)(MG/sup +/).

  9. Extractive spectrophotometric determination of uranium with malachite green

    International Nuclear Information System (INIS)

    Dubey, S.C.; Nadkarni, M.N.

    1977-01-01

    A sensitive spectrophotometric method based on the extraction of a uranium-benzoate-Malachite Green complex by chlorobenzene is described. The absorption maximum is at 635 nm and the molar absorptivity is 8.3 x 10 4 1. mole -1 cm -1 . A preliminary separation of uranium by extraction with methyl isobutyl ketone from acid-deficient aluminium nitrate solution is used to avoid interferences. An aliquot of the extract in then diluted with chlorobenzene and shaken with benzoate buffer containing Malachite Green (MG). The method has been applied for the determination of uranium in a synthetic leach solution. The complex extracted is probably [U0 2 (C 6 H 5 C00 3 - ][MG + ]. (author)

  10. Spectrophotometric determination of La (III) with sulphamethoxazole based hydroxy triazene

    International Nuclear Information System (INIS)

    Manwani, Sapana; Chauhan, R.S.; Goswami, A.K.

    2015-01-01

    In the present study, 3-hydroxy-3-p-chlorophenyll-1-(4-amino-N-(5-methyl-1,2-oxazole-3- yl) benzenesulphonamide-methane) triazene has been synthesized by coupling of hydroxylamine obtained by reduction of nitro compound with diazonium salt obtained from sulphamethoxazole taking hydroxylamine in excess at temperature between 0-5°C. Chemical structure of the synthesized compound was confirmed by IR, 1 H NMR, MASS and by elemental analysis. The complex of the reagent with La (III) has been studied. 3-hydroxy-3-p-chlorophenyll-1-(4-amino-N-(5-methyl-1,2-oxazole-3-yl) benzenesulphonamide-methane) triazene has been used for spectrophotometric determination of lanthanum (III) at 392 nm, keeping the pH between 8.5 to 8.9

  11. ATPase Activity Measurements by an Enzyme-Coupled Spectrophotometric Assay.

    Science.gov (United States)

    Sehgal, Pankaj; Olesen, Claus; Møller, Jesper V

    2016-01-01

    Enzymatic coupled assays are usually based on the spectrophotometric registration of changes in NADH/NAD(+) or NADPH/NADP(+) absorption at 340 nm accompanying the oxidation/reduction of reactants that by dehydrogenases and other helper enzymes are linked to the activity of the enzymatic reaction under study. The present NADH-ATP-coupled assay for ATPase activity is a seemingly somewhat complicated procedure, but in practice adaptation to performance is easily acquired. It is a more safe and elegant method than colorimetric methods, but not suitable for handling large number of samples, and also presupposes that the activity of the helper enzymes is not severely affected by the chemical environment of the sample in which it is tested.

  12. Spectrophotometric investigation of vanadium(4) complexing with monoamine complexones

    International Nuclear Information System (INIS)

    Merkulov, D.A.; Kornev, V.I.

    1998-01-01

    Interaction of vanadium(4) with iminodiacetic (H 2 Ida) and methyliminodiacetic (H 2 Mida) acids by μ = 0.1 (NaClO 4 ) and t = 20±2 deg C is studied through the spectrophotometric method. It is established that the process of complex formation in quasi-binary systems due to competitive effect of hydroxide ions depends to a large degree on the ligands concentration and properties. The VOIda, VO(OH)Ida - , VOMida, VO(OH)Mida - complexes are identified. The stability constants logarithms of these complexes are equal correspondingly to 9.81±0.02, 18.19±0.03, 10.15±0.03, 18.34±0.02. The results of the study on the VO 2+ -HIda and VO 2+ -H 2 Mida systems agree well with the regularities, identified by the study on the vanadium(4) complex formation with other complexones of the iminodiacetate series

  13. Determination of lisinopril in pharmaceuticals by a kinetic spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Čakar Mira

    2012-01-01

    Full Text Available A kinetic spectrophotometric method for determination of lisinopril in pharmaceuticals has been developed. The method is based on activator action of lisinopril on Cu(II ions catalysing the oxidation of nile blue A with hydrogen peroxide in borate buffer (pH 9.3. A decrease of the absorbance was recorded at 635 nm for 5 min at 25°C. The linearity was established applying the tangent method within the concentration range of lisinopril from 0.8-6.4 μg mL-1, the detection and quantification limits being 0.158 μg mL-1 and 0.480 μg mL-1, respectively. The method has been successfully applied in three brands of tablets containing lisinopril alone or in combination with hydrochlorothiazide.

  14. Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Barzegar, Mohsen [Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Jabbari, Ali [K. N. Toosi University, Tehran (Iran, Islamic Republic of); Esmaeili, Majid [Razi University, Kermanshah (Iran, Islamic Republic of)

    2003-09-15

    A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples.

  15. Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

    International Nuclear Information System (INIS)

    Barzegar, Mohsen; Jabbari, Ali; Esmaeili, Majid

    2003-01-01

    A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples

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

    Energy Technology Data Exchange (ETDEWEB)

    Tishchenko, M A; Gerasimenko, G I; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

    1981-01-01

    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:Ant: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.

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

    International Nuclear Information System (INIS)

    Tishchenko, M.A.; Gerasimenko, G.I.; Poluehktov, N.S.

    1981-01-01

    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 [ru

  18. Spectrophotometric determination of catecholamine using vanadium and eriochrome cyanine r

    International Nuclear Information System (INIS)

    Nagaraja, Padmarajaiah; Shrestha, Ashwinee Kumar; Shivakumar, Anantharaman; Al-Tayar, Naef Ghallab Saeed; Gowda, Avinask K.

    2011-01-01

    highly sensitive spectrophotometric method for the analysis of catecholamine drugs; L-dopa and methyldopa, is described. The analysis is based on the reaction of drug molecules with vanadium (V) which is reduced to vanadium (IV) and form complex with eriochrome cyanine R to give products having maximum absorbance (λ max ) at 565 nm. Beer's law is obeyed in the range 0.028-0.84 and 0.099-0.996 μg mL -1 for L-dopa and methyldopa, respectively. The statistical analysis as well as comparison with reported methods demonstrated high precision and accuracy of the proposed method. The method was successfully applied in the analysis of pharmaceutical preparations. (author)

  19. DLLME-spectrophotometric determination of glyphosate residue in legumes.

    Science.gov (United States)

    Çetin, Emine; Şahan, Serkan; Ülgen, Ahmet; Şahin, Uğur

    2017-09-01

    A new separation and pre-concentration method for spectrophotometric determination of glyphosate herbicide was developed. Glyphosate was converted into dithiocarbamic acid with CS 2 , followed by copper in the presence of ammonia to promote complex formation. This complex was collected in a CH 2 Cl 2 organic drop and absorbance measured at 435nm. The analytical parameters, such as the amount of NH 3 , Cu(II) and CS 2 , type of extraction solutions, and the ratio of dispersive and organic liquids were optimized. The calibration curve was linear in the range 0.5-10mgl -1 . The limits of detection and quantification were calculated from 3s to 10s criterions as 0.21mgl -1 and 0.70mgl -1 , respectively. The developed method was applied to legume samples with the satisfactory recovery values of 98±4-102±3%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Speciation and spectrophotometric determination of uranium in seawater

    Directory of Open Access Journals (Sweden)

    M. KONSTANTINOU

    2004-06-01

    Full Text Available A series of ion-exchange and extraction procedures for the separation of uranium from seawater samples and subsequent spectrophotometric determination of uranium in seawater by means of arsenazo(III is described. According to the measurements performed by means of traced samples at every stage of separation, the yield of the pre-analytical procedures is generally over 90% and the separation of uranium very selective. The mean uranium concentration in seawater samples collected from five different coastal areas in Cyprus was found to be 3.2 ± 0.2 & micro; g L-1. Uranium in seawater is stable in its hexavalent oxidation state and UO2 (CO334- is the predominant species under normal coastal conditions (pH ≥ 8, EH ≥ 0.35 mV, 1 atm and 0.03% CO2.

  1. Determination of dissolved inorganic species of iodine by spectrophotometric titration

    Energy Technology Data Exchange (ETDEWEB)

    Pesavento, Maria; Profumo, Antonella; Biesuz, Raffaela

    1987-09-01

    A method for determining iodate and iodine (+1) in aqueous solutions is proposed. The assay is similar to a previously described method for the determination of iodide and iodine (O), which were titrated with standard iodate in hydrochloric acid solution. A sample solution made 0.5-1.5 M in hydrochloric acid is titrated with a standard iodide solution and monitored spectrophotometrically at 230 nm. The species involved have strong absorbances that are well differentiated at this wavelength. By combining the two titrations it is possible to resolve any mixture of species of iodine in different oxidation states. The precision of the method (standard deviation) is the same both when determining a single species (IO/sub 3/-,I+,1/sub 2/ or I-) and a mixture, and is equal to 2 x 10/sup -7/ M. Chloride and bromide, even at very high concentrations, do not interfere.

  2. Determination of dissolved inorganic species of iodine by spectrophotometric titration

    International Nuclear Information System (INIS)

    Pesavento, Maria; Profumo, Antonella

    1987-01-01

    A method for determining iodate and iodine (+1) in aqueous solutions is proposed. The assay is similar to a previously described method for the determination of iodide and iodine (O), which were titrated with standard iodate in hydrochloric acid solution. A sample solution made 0.5-1.5 M in hydrochloric acid is titrated with a standard iodide solution and monitored spectrophotometrically at 230 nm. The species involved have strong absorbances that are well differentiated at this wavelength. By combining the two titrations it is possible to resolve any mixture of species of iodine in different oxidation states. The precision of the method (standard deviation) is the same both when determining a single species (IO 3 -,I+,1 2 or I-) and a mixture, and is equal to 2 x 10 -7 M. Chloride and bromide, even at very high concentrations, do not interfere. (author)

  3. Spectrophotometric Methods for the Assay of Fluvoxamine Using Chromogenic Reagents

    Directory of Open Access Journals (Sweden)

    V. Annapurna

    2010-01-01

    Full Text Available Simple, accurate and reproducible UV-Visible spectrophotometric methods were established for the assay of FXA based on the oxidative coupling and condensation reactions. Condensation and coupling of the FXA with Ninhydrin-Ascorbic acid is proposed in method A. Method B includes complexation of FXA with cobalt thiocyanate. The ligating property of FXA with sodium nitro prusside is incorporated in method C. The optical characteristics such as Beers law limits, molar absorptivity and Sandell’s sensitivity for the methods (A-C are given. Regression analysis using the method of least squares was made to evaluate the slope(b, intercept(a and correlation coefficient (r and standard error of estimation (Se for each system. Determination of FXA in bulk form and in pharmaceutical formulations were also incorporated.

  4. Validation of a spectrophotometric method for quantification of carboxyhemoglobin.

    Science.gov (United States)

    Luchini, Paulo D; Leyton, Jaime F; Strombech, Maria de Lourdes C; Ponce, Julio C; Jesus, Maria das Graças S; Leyton, Vilma

    2009-10-01

    The measurement of carboxyhemoglobin (COHb) levels in blood is a valuable procedure to confirm exposure to carbon monoxide (CO) either for forensic or occupational matters. A previously described method using spectrophotometric readings at 420 and 432 nm after reduction of oxyhemoglobin (O(2)Hb) and methemoglobin with sodium hydrosulfite solution leads to an exponential curve. This curve, used with pre-established factors, serves well for lower concentrations (1-7%) or for high concentrations (> 20%) but very rarely for both. The authors have observed that small variations on the previously described factors F1, F2, and F3, obtained from readings for 100% COHb and 100% O(2)Hb, turn into significant changes in COHb% results and propose that these factors should be determined every time COHb is measured by reading CO and O(2) saturated samples. This practice leads to an increase in accuracy and precision.

  5. Spectrophotometric characterization of hemozoin as a malaria biomarker

    Science.gov (United States)

    Silva, Ivo; Lima, Rui; Minas, Graça.; Catarino, Susana O.

    2017-08-01

    Malaria is a parasitic disease with more than a billion people worldwide at risk of contraction. The disease is predominantly widespread in regions with precarious healthcare conditions and resources. Despite the several available malaria diagnostic methods, only two are predominantly used in the field in malaria-endemic countries: microscopy and rapid diagnostic tests. In this work, an alternative diagnostic system is proposed, based on optical absorption spectrophotometry. The main objective of this paper is the spectrophotometric study of hemozoin as a malaria biomarker, since it is a sub-product of the malaria infection. The optical absorbance of hemoglobin and hemozoin solutions in purified water was measured in the visible spectrum range using a spectrophotometric setup. The results showed main absorbance peaks at 540 nm and 574 nm for hemoglobin, and at 672 nm for hemozoin. The tests performed in aqueous solutions have shown that both hemoglobin and synthetic hemozoin, when alone in solution, were detected by absorbance, with sensitivity of 0.05 g/L, and with a high linearity (R2> 0.92 for all wavelength peaks). Furthermore, it was found that the whole blood and the hemoglobin spectra have similar absorption peaks. By combining whole blood and synthetic hemozoin solutions, it was proved that both the hemozoin and the hemoglobin absorbance peaks could still be detected by spectrophotometry. For instance, in polydimethylsiloxane wells, the proposed method was able to detect hemozoin in whole blood samples for optical paths as low as 3 mm in cylindrical wells, thus proving the capability for this method's miniaturization. With this work, it is possible to conclude that hemozoin is a viable candidate as a biomarker for malaria detection by optical absorption spectrophotometry and also, that an autonomous, fully integrated and low cost miniaturized system, based on such a principle, could provide an efficient diagnosis of malaria.

  6. Spectrophotometric determination of the sulfhydryl containing drug mesna

    Directory of Open Access Journals (Sweden)

    Rim S. Haggag

    2016-06-01

    Full Text Available Four simple and sensitive spectrophotometric methods were developed for the determination of the sulfhydryl containing drug mesna (MSN. Methods I and II rely on nucleophilic aromatic substitution reactions using two UV tagging reagents namely: 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl for method I and 2,4-dinitrofluorobenzene (DNFB for method II. Both reactions took place in alkaline buffered medium and the obtained yellowish products were measured at 414 and 332 nm for methods I and II, respectively. Methods III and IV are indirect spectrophotometric methods based on the suppressive effect of MSN on the absorption of two ternary complex systems which are composed of 1,10-phenanthroline, silver and eosin for method III and 1,10-phenanthroline, silver and bromopyrogallol red for method IV. The decrease in absorbance of the ternary complexes was measured at 547 and 635 nm for methods III and IV, respectively. All the experimental parameters affecting these reactions were carefully studied and optimized. The methods were validated as per the ICH guidelines. The methods were applicable in the linearity ranges 4–18 μg/mL for method I, 4–16 μg/mL for method II, 0.25–2.25 μg/mL for method III and 0.25–1.75 μg/mL for method IV. The proposed methods were successfully applied for the analysis of MSN in its commercial ampoules and no interference was encountered from the present excipients as indicated by the satisfactory percentage recoveries. The results obtained were in a good agreement with those obtained from a previously published method of the investigated drug.

  7. Safety and reliability criteria

    International Nuclear Information System (INIS)

    O'Neil, R.

    1978-01-01

    Nuclear power plants and, in particular, reactor pressure boundary components have unique reliability requirements, in that usually no significant redundancy is possible, and a single failure can give rise to possible widespread core damage and fission product release. Reliability may be required for availability or safety reasons, but in the case of the pressure boundary and certain other systems safety may dominate. Possible Safety and Reliability (S and R) criteria are proposed which would produce acceptable reactor design. Without some S and R requirement the designer has no way of knowing how far he must go in analysing his system or component, or whether his proposed solution is likely to gain acceptance. The paper shows how reliability targets for given components and systems can be individually considered against the derived S and R criteria at the design and construction stage. Since in the case of nuclear pressure boundary components there is often very little direct experience on which to base reliability studies, relevant non-nuclear experience is examined. (author)

  8. SHARDS: a spectro-photometric analysis of distant red and dead massive galaxies

    Science.gov (United States)

    Pérez-González, P. G.; Cava, A.; The Shards Team

    2013-05-01

    SHARDS, an ESO/GTC Large Program, is an ultra-deep (26.5 mag) spectro-photometric survey carried out with GTC/OSIRIS and designed to select and study massive passively evolving galaxies at z= 1.0--2.5 in the GOODS-N field. The survey uses a set of 24 medium band filters (FWHM ˜15 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 populations (older than 0.5 Gyr). These observations are being used to: (1) construct for the first time an unbiased sample of high-z quiescent galaxies, which extends to fainter magnitudes the samples selected with color techniques and spectroscopic surveys; (2) derive accurate ages and stellar masses based on robust measurements of spectral features such as the Mg(UV) or D(4000) indices; (3) measure their redshift with an accuracy Δ z/(1+z)<0.02; and (4) study emission-line galaxies (starbursts and AGN) up to very high redshifts. The well-sampled optical SEDs provided by SHARDS for all sources in the GOODS-N field are a valuable complement for current and future surveys carried out with other telescopes (e.g., Spitzer, HST, and Herschel).

  9. Spectrophotometric method for the determination of thorium in UO2 pellets

    International Nuclear Information System (INIS)

    Acosta L, E.

    1995-04-01

    This report presents a procedure with the description of the spectrophotometric method for the determination of the thorium element in uranium products including powders and pellets of uranium dioxide. Quantities can be determined starting from 1 ppm. (Author)

  10. Polarographic, spectrophotometric and coulometric studies of MoO=4 in H2SO4

    International Nuclear Information System (INIS)

    Tokoro, R.; Bertotti, M.

    1990-01-01

    This study characterizes the polarographic process of Mo O sup(=) sub(4) in H sub(2)SO sub(4) medium, determining which species is responsible by catalytic cycle. Spectrophotometric and coulometric studies are also described. (author)

  11. Spectrophotometric reading of EUCAST antifungal susceptibility testing of Aspergillus fumigatus

    DEFF Research Database (Denmark)

    Meletiadis, J.; Leth Mortensen, K.; Verweij, P. E.

    2017-01-01

    with spectrophotometrically determined MICs and essential (±1 twofold dilution) and categorical (susceptible/intermediate/resistant or wild-type/non-wild-type) agreement was calculated. Spectrophotometric data were analysed with regression analysis using the Emax model, and the effective concentration corresponding to 5% (EC......5) was estimated. Results Using the 5% cut-off, high essential (92%–97%) and categorical (93%–99%) agreement (

  12. Titrimetric and Spectrophotometric Determination of Metaprolol tartrate in Pharmaceuticals Using N-Bromosuccinimide

    OpenAIRE

    K. Basavaiah; B. C. Somashekar

    2007-01-01

    One titrimetric and two spectrophotometric methods are presented for the assay of metaprolol tartrate (MPT) in bulk drug and in tablets. The methods employ N-bromosuccinimide (NBS) as the oxidimetric reagent and two dyes, methyl orange and indigo carmine as spectrophotometric reagents. In titrimetry, an acidified solution of MPT is treated with a known excess amount of NBS and after a definite time, the unreacted oxidant is determined by iodometric back titration. Spectrophotometry involve...

  13. Application of spectrophotometric, densitometric, and HPLC techniques as stability indicating methods for determination of Zaleplon in pharmaceutical preparations

    Science.gov (United States)

    Metwally, Fadia H.; Abdelkawy, M.; Abdelwahab, Nada S.

    2007-12-01

    Spectrophotometric, spectrodensitometric and HPLC are stability indicating methods described for determination of Zaleplon in pure and dosage forms. As Zaleplon is easily degradable, the proposed techniques in this manuscript are adopted for its determination in presence of its alkaline degradation product, namely N-[4-(3-cyano-pyrazolo[1,5a]pyridin-7-yl)-phenyl]- N-ethyl-acetamide. These approaches are successfully applied to quantify Zaleplon using the information included in the absorption spectra of appropriate solutions. The second derivative (D 2) spectrophotometric method, allows determination of Zaleplon without interference of its degradate at 235.2 nm using 0.01N HCl as a solvent with obedience to Beer's law over a concentration range of 1-10 μg ml -1 with mean percentage recovery 100.24 ± 0.86%. The first derivative of the ratio spectra ( 1DD) based on the simultaneous use of ( 1DD) and measurement at 241.8 nm using the same solvent and over the same concentration range as (D 2) spectrophotometric method, with mean percentage recovery 99.9 ± 1.07%. The spectrodensitometric analysis allows the separation and quantitation of Zaleplon from its degradate on silica gel plates using chloroform:acetone:ammonia solution (9:1:0.2 by volume) as a mobile phase. This method depends on quantitave densitometric evaluation of thin layer chromatogram of Zaleplon at 338 nm over a concentration range of 0.2-1 μg band -1, with mean percentage recovery 99.73 ± 1.35. Also a reversed-phase liquid chromatographic method using 5-C8 (22 cm × 4.6 mm i.d. 5 μm particle size) column was described and validated for quantitation of Zaleplon using acetonitrile:deionised water (35:65, v/v) as a mobile phase using Paracetamol as internal standard and a flow rate of 1.5 ml min -1 with UV detection of the effluent at 232 nm at ambient temperature over a concentration range of 2-20 μg ml -1 with mean percentage recovery 100.19 ± 1.15%. The insignificance difference of the proposed

  14. Stability indicating spectrophotometric and spectrodensitometric methods for the determination of diatrizoate sodium in presence of its degradation product

    Science.gov (United States)

    Abd El-Rahman, Mohamed K.; Riad, Safaa M.; Abdel Gawad, Sherif A.; Fawaz, Esraa M.; Shehata, Mostafa A.

    2015-02-01

    Three sensitive, selective, and precise stability indicating methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA), in the presence of its acidic degradation product (highly cytotoxic 3,5 diamino metabolite) and in pharmaceutical formulation were developed and validated. The first method is a first derivative (D1) spectrophotometric one, which allows the determination of DTA in the presence of its degradate at 231.2 nm (corresponding to zero crossing of the degradate) over a concentration range of 2-24 μg/mL with mean percentage recovery 99.95 ± 0.97%. The second method is the first derivative of the ratio spectra (DD1) by measuring the peak amplitude at 227 nm over the same concentration range as D1 spectrophotometric method, with mean percentage recovery 99.99 ± 1.15%. The third method is a TLC-densitometric one, where DTA was separated from its degradate on silica gel plates using chloroform:methanol:ammonium hydroxide (20:10:2 by volume) as a developing system. This method depends on quantitative densitometric evaluation of thin layer chromatogram of DTA at 238 nm over a concentration range of 4-20 μg/spot, with mean percentage recovery 99.88 ± 0.89%. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  15. An Introduction To Reliability

    International Nuclear Information System (INIS)

    Park, Kyoung Su

    1993-08-01

    This book introduces reliability with definition of reliability, requirement of reliability, system of life cycle and reliability, reliability and failure rate such as summary, reliability characteristic, chance failure, failure rate which changes over time, failure mode, replacement, reliability in engineering design, reliability test over assumption of failure rate, and drawing of reliability data, prediction of system reliability, conservation of system, failure such as summary and failure relay and analysis of system safety.

  16. Liquid-liquid microextraction in a multicommuted flow system for direct spectrophotometric determination of iodine value in biodiesel.

    Science.gov (United States)

    Pereira, Andréia C; Rocha, Fábio R P

    2014-06-04

    A flow-based procedure was developed for the direct spectrophotometric determination of the iodine value (IV) in biodiesel. The procedure was based on the microextraction/reaction of unsaturated compounds with triiodide ions in an aqueous medium by inserting the reagent solution between the aliquots of biodiesel without any pretreatment. The interaction occurred through the biodiesel film formed on the inner walls of the hydrophobic tube used as the reactor and at the aqueous/biodiesel interfaces. The spectrophotometric detection was based on the discoloration of the I3(-) reagent in the aqueous phase by using a glass tube coupled to a fiber-optic spectrophotometer as the detection cell. Reference solutions were prepared by dilution of biodiesel samples with previously determined IV in hexane. The analytical response was linear for IV from 13 to 135 g I2/100 g with a detection limit of 5 g I2/100 g. A coefficient of variation of 1.7% (n=10) and a sampling rate of 108 determinations per hour were achieved by consuming 224 μL of the sample and 200 μg of I2 per determination. The slopes of analytical curves obtained with three different biodiesel samples were in agreement (variations in slopes lower than 3.1%), thus indicating an absence of any matrix effects. Results for biodiesel samples from different sources agreed with the volumetric official procedure at the 95% confidence level. The proposed procedure is therefore a simple, fast, and reliable alternative for estimating the iodine value of biodiesel. Copyright © 2014. Published by Elsevier B.V.

  17. THE SPECTROPHOTOMETRIC DETERMINATION OF NITRITES WITH N,N-DIETHYLANILINE

    Directory of Open Access Journals (Sweden)

    O. S. Pogrebnyak

    2015-11-01

    Full Text Available A new spectrophotometric method for nitrite determination was proposed. The method is based on the measurement of absorbance of the N,N-diethylaniline nitrosation product at 475 nm in the hydrochloric acid medium. The optimum concentrations and the influence of various conditions on the determination sensitivity have been determined. The detection limit (blank + 3s for nitrite is 0.98 mg∙L–1 where sis the standard deviation of blank estimation. The linearity range of the calibration graph was over 1.0–100 mg∙L–1 of  nitrite (sr≤ 0.029, n = 8. The metrological characteristics of the procedure were checked by means of method of additives on the control samples and natural waters. The relative error did not exceed 0.06 for nitrite determination on the control samples. The effect of foreign ions in nitrite determination of 1,0∙10−3 mol∙L–1 has been studied. The proposed procedure is simple  and suitable for nitrite determination in various objects.

  18. Simultaneous spectrophotometric determination of tungsten and molybdenum with dithiol

    International Nuclear Information System (INIS)

    Navale, A.S.

    1987-01-01

    Toluene-3,4-dithiol is a very sensitive reagent for the spectrophotometric determination of tungsten and molybdenum. Since the absorption spectra of the dithiol complexes of these two elements overlap, a separation of the two elements is carried out. This leads to time consuming extraction procedures. Measuring the absorption of the mixed complexes at two wavelengths and solving a set of simultaneous equations is also not favorable because a lot of time and effort is required for solving the simultaneous equations for each sample. A faster and simpler method is described here for the simultaneous determination of the two elements. The method is based on measurement of absorbance of the mixed complexes at three pre-selected wavelengths and simple calculations involving the absorbance differences. The criteria for selecting the three wavelengths and the theory are described. Application of the method for the determination of tungsten and molybdenum in ore samples is presented. The method is applicable to any similar system consisting of two interfering components. 4 figures, 2 tables, 6 refs. (author)

  19. Spectrophotometric Determination of Lamivudine in Pure and Tablet Forms

    Directory of Open Access Journals (Sweden)

    A. Biksham Babu

    2012-01-01

    Full Text Available Two visible spectrophotometric methods have been developed for the determination of Lamivudine(LMV in pure and tablet forms. Method-A is based on oxidation of 3-methyl-2-benzathiazolinone hydrazone (MBTH in the presence of iodoso benzene diacetate (IBDA to form electrophilic intermediate which is an active coupling species that reacts with the coupler (LMV by electrophillic attack on the most nucleophilic site on cyclic ring of the coupler. Method-B depends on diazonium salt formation and consequent reaction with resorcinol producing colored product. The absorbances are measured at 590 nm and 540 nm for Method-A and Method-B respectively. Beer's law is obeyed in the concentration range of 10.0-60.0 μg/mL for both the methods. The correlation coefficient which is very close to unity indicates that there is good correlation between concentration and absorbance. LOD, LOQ, confidence levels and relative standard deviation are calculated for the developed methods. The developed methods were successfully applied to tablet forms.

  20. Spectrophotometric readout for an alanine dosimeter for food irradiation applications

    International Nuclear Information System (INIS)

    Ebraheem, S.; Beshir, W.B.; Eid, S.; Sobhy, R.; Kovacs, A.

    2003-01-01

    The alanine-electron spin resonance (EPR) readout system is well known as a reference and transfer dosimetry system for the evaluation of high doses in radiation processing. The high cost of an EPR/alanine dosimetry system is a serious handicap for large-scale routine application in irradiation facilities. In this study, the use of a complex produced by dissolving irradiated L-alanine in 1,4-phenyl diammonium dichloride solution was investigated for dosimetry purposes. This complex--having a purple colour--has an increasing absorbance with increasing dose in the range of 1-20 kGy. The applicability of spectrophotometric evaluation was studied by measuring the absorbance intensity of this complex at 360 and 505 nm, respectively. Fluorimetric evaluation was also investigated by measuring the emission of the complex at 435 nm as a function of dose. The present method is easy for routine application. The effect of the dye concentration as well as the suitable amount of irradiated alanine has been studied. With respect to routine application, the stability of the product complex after its formation was also investigated

  1. Spectrophotometric determination of total lactones in Andrographis paniculata Nees

    Directory of Open Access Journals (Sweden)

    Napaporn Jantakun

    2005-11-01

    Full Text Available A spectrophotometric method for determination of total lactones in Andrographis paniculata was established by using dinitrobenzoic acid and potassium hydroxide solutions as colour forming agents. The absorbance of the solution was determined at 536 nm. The linearity range was 12-72 × 10-6 g.ml-1. The detection limit was 1.2 μg, the quantitation limit was 4.23 μg. The intraday variation had an average of slope 6082.97 g.ml-1, % RSD 0.10; an average intercept 0.2786, %RSD 3.66 (n=3. The interday variation had an average of 6146 g.ml-1 with the %RSD of 6.30 and an average intercept 0.2628, %RSD 4.95 (n=4. The coefficients of determination were 0.998-0.999. The total lactones content, calculated as andrographolide, determined by this method was 8.61±0.52% (n=4 and by the official method, Thai Herbal Pharmacopoeia, was 8.12±0.34% (n=2. The results of the two methods do not differ significantly at P=0.05 (P(|t|>0.903 = 0.53

  2. Verification of spectrophotometric method for nitrate analysis in water samples

    Science.gov (United States)

    Kurniawati, Puji; Gusrianti, Reny; Dwisiwi, Bledug Bernanti; Purbaningtias, Tri Esti; Wiyantoko, Bayu

    2017-12-01

    The aim of this research was to verify the spectrophotometric method to analyze nitrate in water samples using APHA 2012 Section 4500 NO3-B method. The verification parameters used were: linearity, method detection limit, level of quantitation, level of linearity, accuracy and precision. Linearity was obtained by using 0 to 50 mg/L nitrate standard solution and the correlation coefficient of standard calibration linear regression equation was 0.9981. The method detection limit (MDL) was defined as 0,1294 mg/L and limit of quantitation (LOQ) was 0,4117 mg/L. The result of a level of linearity (LOL) was 50 mg/L and nitrate concentration 10 to 50 mg/L was linear with a level of confidence was 99%. The accuracy was determined through recovery value was 109.1907%. The precision value was observed using % relative standard deviation (%RSD) from repeatability and its result was 1.0886%. The tested performance criteria showed that the methodology was verified under the laboratory conditions.

  3. Spectrophotometric determination of boric acid in boron powder with curcumin

    International Nuclear Information System (INIS)

    Grotheer, E.W.

    1979-01-01

    A rapid and accurate method was needed to determine trace amounts of boric acid for quality control and specification testing of elemental boron. The reaction between boric acid and curcumin occurs at a measurable rate only when the curcumin molecule is protonated. Protonation takes place at the carbonyl groups in the presence of a strong acid and occurs completely and rapidly when sulfuric acid is added to a solution of curcumin in acetic acid. Spectrophotometric measurements were made. The extraction of boric acid from boron powder was found to be complete within 2h when either water or the diol solution was used. Whatman No. 40 cr 42 filter paper was used to obtain diol samples free of boron particles. The extraction efficiency of 2-ethyl-1,3-hexanediol was evaluated by adding 1 ml of 500 ppM aqueous boric acid and 1 drop of 10% NaOH to accurately weighed samples of boron powder. The water then was evaporated at room temperature and the samples were extracted with diol solution. The data obtained are included. The extraction efficiency also was evaluated by determining the boric acid content of boron which had been recovered from a previous extraction and boric acid determination. The determination of boric acid using curcumin is unaffected by the presence of other compounds, except for fluoride and nitrate ions. 2 tables

  4. Rapid visual and spectrophotometric nitrite detection by cyclometalated ruthenium complex.

    Science.gov (United States)

    Lo, Hoi-Shing; Lo, Ka-Wai; Yeung, Chi-Fung; Wong, Chun-Yuen

    2017-10-16

    Quantitative determination of nitrite ion (NO 2 - ) is of great importance in environmental and clinical investigations. A rapid visual and spectrophotometric assay for NO 2 - detection was developed based on a newly designed ruthenium complex, [Ru(npy)([9]aneS3)(CO)](ClO 4 ) (denoted as RuNPY; npy = 2-(1-naphthyl)pyridine, [9]aneS3 = 1,4,7-trithiacyclononane). This complex traps NO + produced in acidified NO 2 - solution, and yields observable color change within 1 min at room temperature. The assay features excellent dynamic range (1-840 μmol L -1 ) and high selectivity, and its limit of detection (0.39 μmol L -1 ) is also well below the guideline values for drinking water recommended by WHO and U.S. EPA. Practical use of this assay in tap water and human urine was successfully demonstrated. Overall, the rapidity and selectivity of this assay overcome the problems suffered by the commonly used modified Griess assays for nitrite determination. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Titanium Analysis of Ilmenite Bangka by Spectrophotometric Method Using Perhidrol

    International Nuclear Information System (INIS)

    Rusydi-S

    2004-01-01

    Determination of titanium by spectrofotometric method using perhydrol has been done. The purpose of experiment is to find out the condition of titanium analysis of ilmenite by spectrophotometric method. The experiment parameter e c. analysis condition include the Ti-perhydrol complex spectrum, acidity of complex, perhydrol concentration, linearity, influence of anion, limit detection, interfere elements, application of the method using 40 SRM Standard and analysis for ilmenite samples. Result of experiments are spectrum of Ti-perhydrol complex at 410 nm, acidity of complex is the H 2 SO 4 2 M, perhydrol concentration is 0,24 %, the curve calibration is linier at 1-80 ppm, anion of PO 4 , NO 3 , Cl, CO 3 not be influence until 2000 ppm, limit detection is 0,30 ppm and Mo, V is interfere. The method which was aplicated to 40 SRM standard, shown that the content of Ti is 1580 ppm while the standard is 1600 ppm, and the content of Ti from ilmenite high grade samples is 31,46 % and low grade is 13,55 %. (author)

  6. 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.

  7. Sensitive flow-injection spectrophotometric analysis of bromopride

    Science.gov (United States)

    Lima, Liliane Spazzapam; Weinert, Patrícia Los; Pezza, Leonardo; Pezza, Helena Redigolo

    2014-12-01

    A flow injection spectrophotometric procedure employing merging zones is proposed for direct bromopride determination in pharmaceutical formulations and biological fluids. The proposed method is based on the reaction between bromopride and p-dimethylaminocinnamaldehyde (p-DAC) in acid medium, in the presence of sodium dodecyl sulfate (SDS), resulting in formation of a violet product (λmax = 565 nm). Experimental design methodologies were used to optimize the experimental conditions. The Beer-Lambert law was obeyed in a bromopride concentration range of 3.63 × 10-7 to 2.90 × 10-5 mol L-1, with a correlation coefficient (r) of 0.9999. The limits of detection and quantification were 1.07 × 10-7 and 3.57 × 10-7 mol L-1, respectively. The proposed method was successfully applied to the determination of bromopride in pharmaceuticals and human urine, and recoveries of the drug from these media were in the ranges 99.6-101.2% and 98.6-102.1%, respectively. This new flow injection procedure does not require any sample pretreatment steps.

  8. 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.)

  9. Spectrophotometric determination of nitrite in simulated Purex Process solutions

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, I.daC. de; Matsuda, H T; Araujo, B.F. de; Araujo, J.A. de

    1984-01-01

    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/sup -6/M for nitrite. The calibration curve is linear in the range of 2 to 30..mu..g NO/sup -//sub 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/sup -//sub 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 10/sup 13/ n.s/sup -1/.cm/sup -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%.

  10. Spectrophotometric assay of creatinine in human serum sample

    Directory of Open Access Journals (Sweden)

    Avinash Krishnegowda

    2017-05-01

    Full Text Available A new spectrophotometric method for the analysis of creatinine concentration in human serum samples is developed. The method explores the oxidation of p-methylamino phenol sulfate (Metol in the presence of copper sulfate and creatinine which yields an intense violet colored species with maximum absorbance at 530 nm. The calibration graph of creatinine by fixed time assay ranged from 4.4 to 620 μM. Recovery of creatinine in human serum samples varied from 101% to 106%. Limit of detection and limit of quantification were 0.145 μM and 0.487 μM respectively. Sandell’s sensitivity was 0.112 μg cm−2 and molar absorptivity was 0.101 × 104 L mol−1 cm−1. Within day precision was 2.5–4.8% and day-to-day precision range was 3.2–7.8%. The robustness and ruggedness of the method expressed in RSD values ranged from 0.78% to 2.12% and 1.32% to 3.46% respectively, suggesting that the developed method was rugged. This method provides good sensitivity and is comparable to standard Jaffe’s method with comparatively less interference from foreign substances.

  11. Sensitive spectrophotometric determination of metoclopramide hydrochloride in dosage forms and spiked human urine using vanillin

    Directory of Open Access Journals (Sweden)

    O. Zenita Devi

    2016-09-01

    Full Text Available A new spectrophotometric method which is simple, sensitive, selective and rapid is described for the determination of metoclopramide hydrochloride (MCP in bulk drug and in dosage forms using vanillin as the chromogenic agent. The method is based on the condensation reaction between primary aromatic amine group present in MCP with aromatic aldehyde, vanillin to produce an intense yellow colored product. The resulting Schiff’s base shows an absorption maximum at 410 nm and the reaction product is stable for more than one day. The reaction was carried out in acetic acid and perchloric acid medium. Beer’s law was obeyed in the concentration range 1.5–15.0 μg ml−1 MCP with a molar absorptivity of 1.89 × 104 l mol−1 cm−1. The limit of detection (LOD and limit of quantification (LOQ were found to be 0.51 and 1.55 μg ml−1, respectively. The method was statistically evaluated by calculating percent relative error (% RE for accuracy and percent relative standard deviation (% RSD for precision, and was applied successfully to the determination of MCP in tablets, in injection and also in spiked human urine. No interference was observed from common additives found in pharmaceutical preparations. The results obtained by the proposed method were validated statistically by comparing the results with those of the reference method by applying the Student’s t-test and F-test. The accuracy and reliability of the method were further ascertained by performing recovery tests via standard-addition technique.

  12. Development of a Spectrophotometric Method for Monitoring Angiotensin-Converting Enzyme in Dairy Products

    Directory of Open Access Journals (Sweden)

    Julijana Tomovska*, S. Presilski, N. Gjorgievski, N. Tomovska1, M. S. Qureshi2 and N. P. Bozinovska3

    2013-01-01

    Full Text Available The angiotensin-converting enzyme (ACE regulates the levels of blood pressure through generation of angiotensin-II from angiotensin-I. It is of great importance to have a reliable and yet simple method for a quantitative determination ACE inhibitory peptides in whey of milk products. A rapid, simple, sensitive and accurate spectrophotometric kinetic method has been developed for determination of ACE inhibitory peptides, using competitive inhibition. Samples of dairy product from the market were used for the determination of ACE inhibitory peptides in whey. Holmquist’s kinetic method was used for determining ACE inhibitory activity in blood serum and Ronca-Testoni method was used for the determination of ACE inhibitory activity in whey. Enzymatic inhibition activity was determined using 0.8 mmol/L FAPGG (N-[3-(Furyl –Acryloyl]-L-Phenylalanyl Glycyl Glycyne as the substrate in 50 mmol/L Tris buffer at pH 8.2 at 37°C and a standard serum containing ACE. First, a solution of whey was mixed in a 1 to 10 ratio with serum (elevation containing high ACE activity. The enzymatic activity was determined by monitoring the decrease in absorbance at 340 nm as result of hydrolysis of the substrate. The concentration of ACE inhibitory peptides was determined from a standard curve of inhibitor concentration versus percent of ACE inhibition. The study suggests that the method possesses good reproducibility and accuracy. The linear range enabled determination of high enzymatic activity of ACE and all ACE inhibitory peptides from dairy products act as competitive inhibitors.

  13. Development of a microtitre-based spectrophotometric method to monitor Babesia divergens growth in vitro.

    Science.gov (United States)

    Malandrin, Laurence; Marchand, Anne-Marie; Chauvin, Alain

    2004-09-01

    Babesia divergens multiplication cycle involves erythrocyte invasion, intracellular division, and erythrocyte lysis with the simultaneous liberation of hemoglobin. We have decided to set up a spectrophotometric protocol based on hemoglobin concentration in the culture supernatants to monitor B. divergens in vitro growth. After the selection of 405 nm as the most appropriate endpoint hemoglobin wavelength in our conditions (hemoglobin concentration in the supernatant), cultures were standardized [1 x 10(9) red blood cell (RBC)/ml, 1-2.5 x 10(5) infected red blood cell (iRBC)/ml] to allow their monitoring over 3 days. The protocol was then compared to the most commonly used growth measurement methods: parasitemia counting and [(3)H]hypoxanthine incorporation. An excellent correlation was demonstrated between A(405) of the culture supernatant and parasitemia of the iRBC, whatever the RBC concentration used in the medium. This correlation was also evidenced between A(405) and [(3)H]hypoxanthine incorporation for [(3)H]hypoxanthine concentrations lower than 4 microCi/ml. Our assays also highlighted the inhibitory effect of [(3)H]hypoxanthine on B. divergens growth even when used at low concentrations (0.8 microCi/ml) and for a short incorporation duration (24 h). This effect was confirmed by both A(405) and parasitemia counting. In conclusion, A(405) measurement of B. divergens culture supernatant represents a simple, rapid, safe, and reliable way to measure the in vitro growth of this parasite. Generation times of three different B. divergens strains were then determined by the protocol described here and varied between 8 h 36 min and 13 h 8 min.

  14. The value of reliability

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Karlström, Anders

    2010-01-01

    We derive the value of reliability in the scheduling of an activity of random duration, such as travel under congested conditions. Using a simple formulation of scheduling utility, we show that the maximal expected utility is linear in the mean and standard deviation of trip duration, regardless...... of the form of the standardised distribution of trip durations. This insight provides a unification of the scheduling model and models that include the standard deviation of trip duration directly as an argument in the cost or utility function. The results generalise approximately to the case where the mean...

  15. Development and Validation of a UV Spectrophotometric and a RP-HPLC Methods for Moexipril Hydrochloride in Pure Form and Pharmaceutical Dosage Form

    International Nuclear Information System (INIS)

    Mastiholimath, V.S.; Gupte, P.P.; Mannur, V.S.

    2012-01-01

    A simple and reliable UV spectrophotometric and high-performance liquid chromatography (HPLC) methods were developed and validated for Moexipril hydrochloride in pure form and pharmaceutical dosage form. The RP-HPLC method was developed on agilant eclipse C 18 , (150 mm x 4.6 mm, 5 μm) with a mobile phase gradient system of 60 % (methanol:acetonitrile (70:30 % v/v)) : 40 % 20 mM ammonium acetate buffer pH 4.5 (v/v) and UV spectrophotometric method was developed in phosphate buffer pH 6.8. The effluent was monitored by SPD-M20A, prominence PDA detector at 210 nm. Calibration curve was linear over the concentration range of 10-35 μg/ml and 1-9 μg/ml for RP-HPLC and UV with a regression coefficient of 0.999. For RP-HPLC method Inter-day and intra-day precision % RSD values were found to be 1.00078 % and 1.49408 % respectively. For UV method 0.73386 % to 1.44111 % for inter day 0.453864 to 1.15542 intra-day precision. Recovery of Moexipril hydrochloride was found to be in the range of 99.8538 % to 101.5614 % and 100.5297586 % to 100.6431587 % for UV and RP-HPLC respectively. The limits of detection (LOD) and quantification (LOQ) for HPLC were 0.98969 and 2.99907 μg/ml, respectively. The developed RP-HPLC and UV spectrophotometric method was successfully applied for the quantitative determination of Moexipril hydrochloride in pharmaceutical dosage. (author)

  16. Application and validation of superior spectrophotometric methods for simultaneous determination of ternary mixture used for hypertension management

    Science.gov (United States)

    Mohamed, Heba M.; Lamie, Nesrine T.

    2016-02-01

    Telmisartan (TL), Hydrochlorothiazide (HZ) and Amlodipine besylate (AM) are co-formulated together for hypertension management. Three smart, specific and precise spectrophotometric methods were applied and validated for simultaneous determination of the three cited drugs. Method A is the ratio isoabsorptive point and ratio difference in subtracted spectra (RIDSS) which is based on dividing the ternary mixture of the studied drugs by the spectrum of AM to get the division spectrum, from which concentration of AM can be obtained by measuring the amplitude values in the plateau region at 360 nm. Then the amplitude value of the plateau region was subtracted from the division spectrum and HZ concentration was obtained by measuring the difference in amplitude values at 278.5 and 306 nm (corresponding to zero difference of TL) while the total concentration of HZ and TL in the mixture was measured at their isoabsorptive point in the division spectrum at 278.5 nm (Aiso). TL concentration is then obtained by subtraction. Method B; double divisor ratio spectra derivative spectrophotometry (RS-DS) and method C; mean centering of ratio spectra (MCR) spectrophotometric methods. The proposed methods did not require any initial separation steps prior the analysis of the three drugs. A comparative study was done between the three methods regarding their; simplicity, sensitivity and limitations. Specificity was investigated by analyzing the synthetic mixtures containing different ratios of the three studied drugs and their tablets dosage form. Statistical comparison of the obtained results with those found by the official methods was done, differences were non-significant in regard to accuracy and precision. The three methods were validated in accordance with ICH guidelines and can be used for quality control laboratories for TL, HZ and AM.

  17. Spectrophotometric and chromatographic determination of insensitive energetic materials: HNS and NTO, in the presence of sensitive nitro-explosives.

    Science.gov (United States)

    Can, Ziya; Uzer, Ayşem; Tekdemir, Yasemin; Erçağ, Erol; Türker, Lemi; Apak, Reşat

    2012-02-15

    As there are no molecular spectroscopic determination methods for the most widely used insensitive energetic materials, 2,2',4,4',6,6'-hexanitrostilbene (HNS) and 3-nitro-1,2,4-triazole-5-one (NTO), in the presence of sensitive nitro-explosives, two novel spectrophotometric methods were developed. For HNS and TNT mixtures, both analytes react with dicyclohexylamine (DCHA) forming different colored charge-transfer complexes, which can be resolved by derivative spectroscopy. The spectrophotometric method for NTO measures the 416-nm absorbance of its yellow-colored Na(+)NTO(-) salt formed with NaOH. TNT, if present, is pre-extracted into IBMK as its Meisenheimer anion forming an ion-pair with the cationic surfactant cetyl pyridinium (CP(+)) in alkaline medium, whereas the unextracted NTO is determined in the aqueous phase. The molar absorptivity (ε, L mol(-1)cm(-1)) and limit of quantification (LOQ, mg L(-1)) are as follows: for HNS, ε=2.75 × 10(4) and LOQ=0.48 (in admixture with TNT); for NTO, ε=6.83 × 10(3) and LOQ=0.73. These methods were not affected from nitramines and nitrate esters in synthetic mixtures or composite explosives. The developed methods were statistically validated against HPLC, and the existing chromatographic method was modified so as to enable NTO determination in the presence of TNT. These simple, low-cost, and versatile methods can be used in criminology, remediation/monitoring of contaminated sites, and kinetic stability modeling of munitions containing desensitized energetic materials. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Spectrophotometric Analysis of Phenolic Compounds in Grapes and Wines.

    Science.gov (United States)

    Aleixandre-Tudo, Jose Luis; Buica, Astrid; Nieuwoudt, Helene; Aleixandre, Jose Luis; du Toit, Wessel

    2017-05-24

    Phenolic compounds are of crucial importance for red wine color and mouthfeel attributes. A large number of enzymatic and chemical reactions involving phenolic compounds take place during winemaking and aging. Despite the large number of published analytical methods for phenolic analyses, the values obtained may vary considerably. In addition, the existing scientific knowledge needs to be updated, but also critically evaluated and simplified for newcomers and wine industry partners. The most used and widely cited spectrophotometric methods for grape and wine phenolic analysis were identified through a bibliometric search using the Science Citation Index-Expanded (SCIE) database accessed through the Web of Science (WOS) platform from Thompson Reuters. The selection of spectrophotometry was based on its ease of use as a routine analytical technique. On the basis of the number of citations, as well as the advantages and disadvantages reported, the modified Somers assay appears as a multistep, simple, and robust procedure that provides a good estimation of the state of the anthocyanins equilibria. Precipitation methods for total tannin levels have also been identified as preferred protocols for these types of compounds. Good reported correlations between methods (methylcellulose precipitable vs bovine serum albumin) and between these and perceived red wine astringency, in combination with the adaptation to high-throughput format, make them suitable for routine analysis. The bovine serum albumin tannin assay also allows for the estimation of the anthocyanins content with the measurement of small and large polymeric pigments. Finally, the measurement of wine color using the CIELab space approach is also suggested as the protocol of choice as it provides good insight into the wine's color properties.

  19. Spectrophotometric studies of marine surfactants in the southern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Violetta Drozdowska

    2015-04-01

    Full Text Available It is well known that surfactants in the southern Baltic Sea constitute the organic matter from riverine waters discharges as well as the secondary degradation products of marine phytoplankton excretion. They reach the surface microlayer by the upwellings and turbulent motions of water and in the membranes of the vesicles as well as from the atmosphere. To assess concentration and spatial distribution of marine surfactants in the southern Baltic Sea, the steady-state spectrophotometric and spectrofluorometric measurements of water samples taken from a surface film and a depth of 0.5 m were carried out. Water samples were collected during windless days of the cruise of r/v ‘Oceania’ in November 2012, from the open and the coastal waters having regard to the vicinity of the Vistula and Łeba mouths. In the present paper, fractions of dissolved organic matter having chromophores (CDOM or fluorophores (FDOM are recognized through their specific spectroscopic behavior, i.e., steady-state absorption, fluorescence excitation and fluorescence spectra. The steady-state spectroscopic measurements revealed the CDOM and FDOM molecules characteristic to both the land and marine origin. Moreover, the concentration and spatial distribution of marine surfactants significantly depend on the distance from the river mouth. Finally, higher values of absorbance and fluorescence intensity observed in a surface film in comparison to these values in a depth of 0.5 m clearly suggest the higher concentration of organic matter in a marine film. On the other hand, our results revealed that a surface microlayer is composed of the same CDOM and FDOM as bulk water.

  20. Novel Spectrophotometric Methods for Determination of Salicylamide and Ascorbic acid in their binary mixture

    International Nuclear Information System (INIS)

    Ali, N.W.; Zaazaa, H.E.S.; Abdelrahman, M.M.

    2014-01-01

    Simple, selective and precise four spectrophotometric methods were developed and validated for quantitative determination of Salicylamide (SAD) and Ascorbic acid (ASC, Vitamin C) in their binary mixture. Method A is Area under curve spectrophotometry, in which the area under curve in the wavelength ranges 225-245 nm and 265-285 nm were selected for determination of SAD and ASC. Method B is based on dual wavelength spectrophotometry, where ASC can be determined by difference in absorbance at 249.8 and 285.8 nm. On the same way; SAD is measured by difference in absorbance at 240.4 and 286.4 nm. Method C utilizes isoabsorptive point spectrophotometry where total concentration of SAD and ASC was calculated at their isoabsorptive points at 246.4 and 287 nm, while SAD concentration alone can be determined by first derivative spectrophotometry (1D) at 315.4 nm, then ASC concentration can be determined by subtraction. Method D is ratio subtraction spectrophotometry, where ASC can be determined by dividing the spectrum of the mixture by the spectrum of the SAD (as a divisor) followed by subtracting the constant absorbance value of the plateau region, then finally multiplying the obtained spectrum by the spectrum of the divisor. The developed methods have been successfully applied for determination of the studied drugs in different laboratory prepared mixtures and in their pharmaceutical formulation. Statistical comparison between the results obtained by applying the proposed methods and the reported HPLC method was done, and it was found that there was no significant difference between them regarding both accuracy and precision. (author)

  1. Spectrophotometric determination of cyclotrimethylenetrinitramine (RDX) in explosive mixtures and residues with the Berthelot reaction.

    Science.gov (United States)

    Uzer, A; Erçağ, E; Apak, R

    2008-03-31

    On-site colorimetric methods are a valuable, cost-effective tool to assess the nature and extent of contamination in remediated sites and to enable on-site screening for police criminology laboratories. The existing colorimetric method for cyclotrimethylenetrinitramine (RDX) based on a Griess reaction suffers from the non-quantitative reduction to nitrite and from the unstable character of HNO2 in acidic medium. Thus we propose a novel spectrophotometric RDX assay in explosive mixtures and residues, based on (Zn+HCl) reduction of RDX in a microwave oven, followed by neutralization of the reduction products to ammonia and low molecular-weight amines, and Berthelot reaction of these amine-compounds with phenol and hypochlorite in alkaline medium to give an intensely blue indophenol dye absorbing at 631nm. The molar absorptivity and limit of detection (LOD) for RDX were (1.08+/-0.04)x10(4) L mol(-1) cm(-1) and 0.18 mg L(-1), respectively. Application of the method to synthetic mixture solutions of RDX and trinitrotoluene (TNT) at varying proportions showed that there was minimal interference from TNT (which could be compensated for by dicyclohexylamine colorimetry), since the Berthelot reaction was essentially non-responsive to m-substituted anilines derived from TNT upon (Zn+HCl) reduction. The proposed method was successfully applied to military-purpose explosive mixtures of (RDX+inert matter) such as Comp A5, Comp C4, and Hexal P30, and to (RDX+TNT) mixtures such as Comp B. The molar absorptivity of RDX was much higher than that of either ammonium or nitrate; RDX could be effectively separated from ammonium and nitrate in soil mixtures, based on solubility differences. The Berthelot method for RDX was statistically validated using Comp B mixtures against standard HPLC equipped with a Hypersil C-18 column with (40% MeOH-60% H2O) mobile phase, and against gas chromatography-thermal energy analysis (GC-TEA) system.

  2. Spectrophotometric method for quantitative determination of triclabendazole in bulk and pharmaceutical

    Directory of Open Access Journals (Sweden)

    Alankar Shrivastava

    2011-01-01

    Full Text Available Background: Triclabendazole (TCBZ, 6-chloro-5(2-3 dichlorophenoxy-2-methyl thio-benzimidazole, an halogenated benzimidazole (BZD thiol derivative, shows high efficacy against both the immature and mature stages of Fasciola hepatica in sheep and cattle, which is a differential feature compared to other available trematodicidal drugs. As a consequence of its excellent activity against the liver fluke, it has been extensively used and this has inevitably promoted the selection of TCBZ-resistant populations, which is now a worrying problem in several areas of the world. We propose simple ultraviolet spectrophotometric method for the estimation of triclabendazole in 0.1 methanolic HCl for the estimation of the drug. Method was validated as per ICH guidelines. Materials and Methods: Spectral absorbance measurements were made on Shimadzu UV-1800 with 10 mm matched quartz cells and dilutions were made in 0.1 M methanolic HCl. Results: The LOD and LOQ of triclabendazole at 305 nm were found to be 0.068434 and 2.73×10-4 μg/ml respectively. The calibration was linear in the range of 1-10 μg/ml. Analytical parameters such as stability, selectivity, accuracy, and precision have been established for the method in Endex and Fasinex tablets and evaluated statistically to assess the application of the method. Conclusion: Method passes all parameters with in desirable limits and found to be simple, stable, sensitive, reproducible, and accurate for the routine analysis of the drug in pharmaceutical formulations and in pharmaceutical investigations involving triclabendazole.

  3. Simultaneous determination of piracetam and vincamine by spectrophotometric and high-performance liquid chromatographic methods.

    Science.gov (United States)

    El-Saharty, Yasser Shaker Ibrahim

    2008-01-01

    A mixture of piracetam and vincamine was determined by 3 different methods. The first was the determination of piracetam and vincamine using the ratio-spectra first-derivative (DD1) spectrophotometric technique at 209 and 293 nm in concentration ranges of 10-45 and 2-14 microg/mL with mean recoveries of 99.22 +/- 0.72 and 99.67 +/- 0.79%, respectively. The second method was based on the resolution of the 2 components by bivariate calibration depending on a mathematic algorithm that provides simplicity and rapidity. The method depended on quantitative evaluation of the absorbencies at 210 and 225 nm in concentration ranges of 5-45 and 2-14 microg/mL, with mean recoveries of 100.33 +/- 0.54 and 100.44 +/- 0.98% for piracetam and vincamine, respectively. The third method was reversed-phase liquid chromatography using 0.05 M potassium dihydrogen phosphate-methanol (50 + 50, v/v) as the mobile phase, with the pH adjusted to 3.5 with phosphoric acid. The eluent was monitored at 215 nm in concentration ranges of 5-100 and 2-200 microg/mL, with mean recoveries of 99.62 +/- 0.67 and 99.32 +/- 0.85% for piracetam and vincamine, respectively. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.

  4. Extraction and spectrophotometric determination of molybdenum with omicron-hydroxythiophenols and aromatic amines

    International Nuclear Information System (INIS)

    Zalov, A.Z.; Verdizade, N.A.

    2015-01-01

    The interaction of molybdenum (VI) with o-hydroxythiophenol derivatives (HTPDs) and aromatic amines (AAs) was studied. The following three HTPDs, which contain different halogen atoms at position 5, were used: 2-hydroxy-5-chlorothiophenol(HCTP), 2-hydroxy-5-bromothiophenol (HBTP), 2-hydroxy-5-iodothiophenol (HITP)). The examined AAs were aniline (An), Nmethylaniline (mAn) and N,N-dimethylaniline (dAn). The obtained ternary complexes have a composition of 1:2:2 (Mo(V):HBTP:AA). Optimal conditions for their liquid-liquid extraction (LLE) were found: organic solvent (chloroform), pH (4-6), concentration of the reagents 10-3moldm-3 (AA)) and 10-3moldm-3 (HTPD) and (1.2-1.5) ((1.3-1.5) extraction time(colour develops almost immediately after the reagents addition). The absorbance of the extracts is stable for at least 48 hours. The optimum shaking time is 10 min.). Under the optimal max) at 515-538 conditions, the complexes have absorption maxima ( 104dm3mol-1 cm-1. The max) between 3.1 nm and molar absorptivities ( 98.4%. The results suggested that linear degrees of extraction were max or relationships exist between the spectral characteristics ( max) and some fundamental properties of the halogen substituent in the HTPD (atomic mass and electronegativity). The effect of foreign ions on the LLE-spectrophotometric determination of molybdenum was examined and two sensitive, selective and precise procedures for molybdenum determination were proposed. The relative standard deviations for Mo 10-4 % were 4% (HCTP-An procedure) and 3% (HBTP-An content of (3-5) procedure). (author)

  5. Frontiers of reliability

    CERN Document Server

    Basu, Asit P; Basu, Sujit K

    1998-01-01

    This volume presents recent results in reliability theory by leading experts in the world. It will prove valuable for researchers, and users of reliability theory. It consists of refereed invited papers on a broad spectrum of topics in reliability. The subjects covered include Bayesian reliability, Bayesian reliability modeling, confounding in a series system, DF tests, Edgeworth approximation to reliability, estimation under random censoring, fault tree reduction for reliability, inference about changes in hazard rates, information theory and reliability, mixture experiment, mixture of Weibul

  6. Extractive spectrophotometric determination of molybdenum using p-chloroisonitroso acetophenone hydrazone

    International Nuclear Information System (INIS)

    Lokhande, R.S.; Agashe, A.P.; Hundiwale, D.G.

    2001-01-01

    Separation technique like solvent extraction can be advantageously employed for the determination of metals at low concentration in micrograms using spectrophotometric methods. Hydrazoxine has been used for the extraction and spectrophotometric determination of metals at trace level as well as for the studies of transition metals in complex form. In the present paper, solvent extraction technique has been used to develop methods for the separation and spectrophotometric determination of Mo(VI) with p-chloroisonitroso acetophenone hydrazone was extracted into chloroform from aqueous solution in the pH range 8 to 8.5. The absorption maxima was also tried for the extracted species and Beer's law was also studied for its applicability. In this, interference from the foreign ion has also been examined. (author)

  7. A Sensitive Validated Spectrophotometric Method for the Determination of Flucloxacillin Sodium

    Directory of Open Access Journals (Sweden)

    R. Singh Gujral

    2009-01-01

    Full Text Available A simple and sensitive spectrophotometric method has been proposed for the determination of flucloxacillin sodium. The determination method is based on charge transfer complexation reaction of the drug with iodine in methanol-dichloromethane medium. The absorbance was measured at 362 nm against the reagent blank. Under optimized experimental conditions, Beer's law is obeyed in the concentration ranges 1-9 μg/mL for flucloxacillin. The method was validated for specificity, linearity, precision, accuracy. The degree of linearity of the calibration curves, the percent recoveries, limit of detection and quantitation for the spectrophotometric method were determined. No interferences could be observed from the additives commonly present in the pharmaceutical formulations. The method was successfully applied for in vitro determination of human urine samples with low RSD value. This is simple, specific, accurate and sensitive spectrophotometric method.

  8. Yonsei Evolutionary Population Synthesis (YEPS). II. Spectro-photometric Evolution of Helium-enhanced Stellar Populations

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chul; Yoon, Suk-Jin; Lee, Young-Wook, E-mail: chulchung@yonsei.ac.kr, E-mail: sjyoon0691@yonsei.ac.kr [Center for Galaxy Evolution Research, Yonsei University, Seoul 03722 (Korea, Republic of)

    2017-06-20

    The discovery of multiple stellar populations in Milky Way globular clusters (GCs) has stimulated various follow-up studies on helium-enhanced stellar populations. Here we present the evolutionary population synthesis models for the spectro-photometric evolution of simple stellar populations (SSPs) with varying initial helium abundance ( Y {sub ini}). We show that Y {sub ini} brings about dramatic changes in spectro-photometric properties of SSPs. Like the normal-helium SSPs, the integrated spectro-photometric evolution of helium-enhanced SSPs is also dependent on metallicity and age for a given Y {sub ini}. We discuss the implications and prospects for the helium-enhanced populations in relation to the second-generation populations found in the Milky Way GCs. All of the models are available at http://web.yonsei.ac.kr/cosmic/data/YEPS.htm.

  9. Effect of bilirubin on the spectrophotometric and radionuclide assay for serum angiotensin-converting enzyme

    International Nuclear Information System (INIS)

    Saxe, A.W.; Hollinger, M.A.; Essam, T.

    1986-01-01

    The effect of bilirubin on serum angiotensin-converting enzyme (ACE) activity was studied with spectrophotometric and radionuclide assays. In the spectrophotometric assay addition of bilirubin to normal serum from dog, mouse, and human produced a dose-related inhibition of ACE activity. A 50% decrease in human ACE activity was produced by the addition of approximately 250 mg/L in vitro. Serum from icteric patients with elevated bilirubin was also associated with a reduction in ACE activity in the spectrophotometric assay. A 50% decrease in ACE activity in these samples was associated with a serum bilirubin of approximately 220 mg/L. In the radionuclide assay, however, addition of bilirubin to normal human serum failed to reduce measured ACE activity. The use of a radionuclide assay for serum ACE in clinical samples offers the advantage of less interference from serum bilirubin

  10. Yonsei Evolutionary Population Synthesis (YEPS). II. Spectro-photometric Evolution of Helium-enhanced Stellar Populations

    International Nuclear Information System (INIS)

    Chung, Chul; Yoon, Suk-Jin; Lee, Young-Wook

    2017-01-01

    The discovery of multiple stellar populations in Milky Way globular clusters (GCs) has stimulated various follow-up studies on helium-enhanced stellar populations. Here we present the evolutionary population synthesis models for the spectro-photometric evolution of simple stellar populations (SSPs) with varying initial helium abundance ( Y ini ). We show that Y ini brings about dramatic changes in spectro-photometric properties of SSPs. Like the normal-helium SSPs, the integrated spectro-photometric evolution of helium-enhanced SSPs is also dependent on metallicity and age for a given Y ini . We discuss the implications and prospects for the helium-enhanced populations in relation to the second-generation populations found in the Milky Way GCs. All of the models are available at http://web.yonsei.ac.kr/cosmic/data/YEPS.htm.

  11. Extraction-spectrophotometric method for silicon determination in high-purity substances. 1. Silicon determination in tellurium

    Energy Technology Data Exchange (ETDEWEB)

    Shaburova, V P; Yudelevich, I G [AN SSSR, Novosibirsk (USSR). Inst. Neorganicheskoj Khimii

    1989-01-01

    The extraction-spectrophotometric method for silicon determination in tellurium based on extraction isolation of the base by tributyl phosphate from hydrochloride solutions and with addition of HNO/sub 3/ and spectrophotometric silicon determination using malachite green is developed. The method permits to determine 2x10/sup -1/-3x10/sup -4/ % Si.

  12. Genetic algorithm-based wavelength selection in multicomponent spectrophotometric determination by PLS: Application on sulfamethoxazole and trimethoprim mixture in bovine milk

    Directory of Open Access Journals (Sweden)

    Givianrad Hadi Mohammad

    2013-01-01

    Full Text Available The simultaneous determination of sulfamethoxazole (SMX and trimethoprim (TMP mixtures in bovine milk by spectrophotometric method is a difficult problem in analytical chemistry, due to spectral interferences. By means of multivariate calibration methods, such as partial least square (PLS regression, it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Genetic algorithm (GA is a suitable method for selecting wavelengths for PLS calibration of mixtures with almost identical spectra without loss of prediction capacity using the spectrophotometric method. In this study, the calibration model based on absorption spectra in the 200-400 nm range for 25 different mixtures of SMX and TMP Calibration matrices were formed form samples containing 0.25-20 and 0.3-21 μg mL-1 for SMX and TMP, at pH=10, respectively. The root mean squared error of deviation (RMSED for SMX and TMP with PLS and genetic algorithm partial least square (GAPLS were 0.242, 0.066 μgmL-1 and 0.074, 0.027 μg mL-1, respectively. This procedure was allowed the simultaneous determination of SMX and TMP in synthetic and real samples and good reliability of the determination was proved.

  13. Innovative spectrophotometric methods for simultaneous estimation of the novel two-drug combination: Sacubitril/Valsartan through two manipulation approaches and a comparative statistical study

    Science.gov (United States)

    Eissa, Maya S.; Abou Al Alamein, Amal M.

    2018-03-01

    Different innovative spectrophotometric methods were introduced for the first time for simultaneous quantification of sacubitril/valsartan in their binary mixture and in their combined dosage form without prior separation through two manipulation approaches. These approaches were developed and based either on two wavelength selection in zero-order absorption spectra namely; dual wavelength method (DWL) at 226 nm and 275 nm for valsartan, induced dual wavelength method (IDW) at 226 nm and 254 nm for sacubitril and advanced absorbance subtraction (AAS) based on their iso-absorptive point at 246 nm (λiso) and 261 nm (sacubitril shows equal absorbance values at the two selected wavelengths) or on ratio spectra using their normalized spectra namely; ratio difference spectrophotometric method (RD) at 225 nm and 264 nm for both of them in their ratio spectra, first derivative of ratio spectra (DR1) at 232 nm for valsartan and 239 nm for sacubitril and mean centering of ratio spectra (MCR) at 260 nm for both of them. Both sacubitril and valsartan showed linearity upon application of these methods in the range of 2.5-25.0 μg/mL. The developed spectrophotmetric methods were successfully applied to the analysis of their combined tablet dosage form ENTRESTO™. The adopted spectrophotometric methods were also validated according to ICH guidelines. The results obtained from the proposed methods were statistically compared to a reported HPLC method using Student t-test, F-test and a comparative study was also developed with one-way ANOVA, showing no statistical difference in accordance to precision and accuracy.

  14. PCA-based algorithm for calibration of spectrophotometric analysers of food

    International Nuclear Information System (INIS)

    Morawski, Roman Z; Miekina, Andrzej

    2013-01-01

    Spectrophotometric analysers of food, being instruments for determination of the composition of food products and ingredients, are today of growing importance for food industry, as well as for food distributors and consumers. Their metrological performance significantly depends of the numerical performance of available means for spectrophotometric data processing; in particular – the means for calibration of analysers. In this paper, a new algorithm for this purpose is proposed, viz. the algorithm using principal components analysis (PCA). It is almost as efficient as PLS-based algorithms of calibration, but much simpler

  15. Validated UV-Spectrophotometric Methods for Determination of Gemifloxacin Mesylate in Pharmaceutical Tablet Dosage Forms

    Directory of Open Access Journals (Sweden)

    R. Rote Ambadas

    2010-01-01

    Full Text Available Two simple, economic and accurate UV spectrophotometric methods have been developed for determination of gemifloxacin mesylate in pharmaceutical tablet formulation. The first UV-spectrophotometric method depends upon the measurement of absorption at the wavelength 263.8 nm. In second area under curve method the wavelength range for detection was selected from 268.5-258.5 nm. Beer’s law was obeyed in the range of 2 to 12 μgmL-1 for both the methods. The proposed methods was validated statistically and applied successfully to determination of gemifloxacin mesylate in pharmaceutical formulation.

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

    Directory of Open Access Journals (Sweden)

    B. Thangabalan

    2009-01-01

    Full Text Available 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 simple, precise, sensitive and reproducible and can be used for the routine quality control testing of the marketed formulations.

  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. System Reliability Engineering

    International Nuclear Information System (INIS)

    Lim, Tae Jin

    2005-02-01

    This book tells of reliability engineering, which includes quality and reliability, reliability data, importance of reliability engineering, reliability and measure, the poisson process like goodness of fit test and the poisson arrival model, reliability estimation like exponential distribution, reliability of systems, availability, preventive maintenance such as replacement policies, minimal repair policy, shock models, spares, group maintenance and periodic inspection, analysis of common cause failure, and analysis model of repair effect.

  19. Spectrophotometric study of Saturn's main rings by means of Monte Carlo ray-tracing and Hapke's theory

    Science.gov (United States)

    Ciarniello, Mauro; Filacchione, Gianrico; D'Aversa, Emiliano; Cuzzi, Jeffrey N.; Capaccioni, Fabrizio; Hedman, Matthew M.; Dalle Ore, Cristina M.; Nicholson, Philip D.; Clark, Roger Nelson; Brown, Robert H.; Cerroni, Priscilla; Spilker, Linda

    2017-10-01

    This work is devoted to the investigation of the spectrophotometric properties of Saturn's rings from Cassini-VIMS (Visible and Infrared Mapping Spectrometer) observations. The dataset used for this analysis is represented by ten radial spectrograms of the rings which have been derived in Filacchione et al. (2014) by radial mosaics produced by VIMS. Spectrograms report the measured radiance factor of the main Saturn's rings as a function of both radial distance (from 73.500 to 141.375 km) and wavelength (0.35-5.1 µm) for different observation geometries (phase angle ranging in the 1.9°-132.2° interval). We take advantage of a Monte Carlo ray-tracing routine to characterize the photometric behavior of the rings at each wavelength and derive the spectral Bond albedo of rings particles. This quantity is used to infer the composition of the regolith covering rings particles by applying Hapke's theory. Four different regions, characterized by different optical depths, and respectively located in the C ring, inner B ring, mid B ring and A ring, have been investigated. Results from spectral modeling indicate that rings spectrum can be described by water ice with minimal inclusion of organic materials (tholin, exogenous material, which is more effective in the less dense regions of the rings because of their lower content of pure water ice.

  20. Validation of high performance liquid chromatographic and spectrophotometric methods for the determination of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products

    Directory of Open Access Journals (Sweden)

    Serpil Sevim

    2015-12-01

    Full Text Available abstract The antiparkinson agent pramipexole dihydrochloride monohydrate was quantified in pharmaceutical products by high performance liquid chromatography (HPLC and derivative spectrophotometry. The first method was based on HPLC using tamsulosin HCl as an internal standard. In this method, chromatographic separation was achieved using a LiChrospher 60 RP column at 25°C, with a flow rate of 1.0 mL/min at 263 nm. The eluent comprised 0.01 mol/L ammonium acetate (pH 4.4 and acetonitrile (35:65 by volume. The linearity range was found to be 10.0-30.0 µg/mL with a mean recovery of 100.5 ± 1.10. The limit of detection (8 ng/mL and limit of quantification (50 ng/mL were calculated. In the second method, the first derivative spectrophotometric technique for the determination of pramipexole dihydrochloride monohydrate was performed by measuring the amplitude at 249 and 280 nm. In the first derivative technique, the absorbance and concentration plot was rectilinear over the 5.0-35.0 µg/mL range with a lower detection limit of 1.5 ng/mL and quantification limit of 4.5 ng/mL. The typical excipients included in the pharmaceutical product do not interfere with the selectivity of either method. The developed methods were validated for robustness, selectivity, specificity, linearity, precision, and accuracy as per the ICH and FDA guidelines (ICH Q2B, 1996; FDA,2000. In conclusion, the developed methods were successful in determining the quantity of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products. The RSD values for the pharmaceutical product used in this study were found to be 0.97% for the HPLC method and 0.00% for the first derivative spectrophotometric method.

  1. Selective determination of cyanide complexes of copper, zinc and cadmium in electrolytes by spectrophotometric titration

    International Nuclear Information System (INIS)

    Kuznetsov, V.V.; Korchagina, O.A.; Samorukova, O.L.

    1986-01-01

    Selective, sensitive and rapid method for determining Cd, Zn, Cu and their mixtures in cyanide electrolytes of galvanic bathes has been developed. Analysis is performed by means of indicator spectrophotometric titration with barium and strontium salts of cadmium cyanide complexes in organic-aqueous solvents

  2. Determination of cyanide by an indirect spectrophotometric method using 5-Br-PADAP.

    Science.gov (United States)

    Fu-Sheng, W; Yu-Qin, L; Fang, Y; Nai-Kui, S

    1981-09-01

    Complexation of Ni(2+) with cyanide inhibits its colour reaction with 5-Br-PADAP and this reaction is used in the spectrophotometric determination of cyanide at the ug level. Cyanide in industrial waste waters is determined after an initial transfer as hydrogen cyanide from the sample into sodium hydroxide solution with a stream of air.

  3. Spectrophotometric investigation into iodine-electron donor systems at low temperature

    International Nuclear Information System (INIS)

    Gorodyskij, V.A.; Morachevskij, A.A.

    1978-01-01

    Iodine-sec. butanol (n-donor) and iodine - hexene - 1 (π-donor) have been investigated for the first time by the spectrophotometric method in the wide temeprature range (77-293 K). The existence of complexes with a charge transfer of the type, which is characterized by the long-wave absorption band in electron spectra, is determined in the systems

  4. Spectrophotometric determination of boron in water with prior distillation and hydrolysis of the methyl borate

    International Nuclear Information System (INIS)

    Monzo, J.; Pomares, F.; Guardia, M. de la

    1988-01-01

    A procedure for the determination of boron in irrigation waters is proposed, involving the prior distillation and hydrolysis of methyl borate and subsequent spectrophotometric determination with azomethine-H. The selectivity is better than that of the direct analysis method. (author)

  5. Using Spectrophotometric Titrations To Characterize Humic Acid Reactivity at Environmental Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Janot, N.; Benedetti, M. F. [Univ Paris Diderot, Lab Geochim Eaux, UMR CNRS 7154, IPGP, F-75025 Paris 13 (France); Janot, N.; Reiller, P. E. [CE Saclay, CEA DEN DANS DPC SECR, Lab Speciat Radionucleides and Mol, F-91191 Gif Sur Yvette (France); Korshin, G. V. [Univ Washington, Dept Civil and Environm Engn, Seattle, WA 98195 (United States)

    2010-07-01

    Potentiometric titration is a common method to characterize dissolved organic matter (DOM) reactivity. Because of the sensitivity of pH electrodes, it is necessary to work with very high DOM ({>=}1 g/L) concentrations that are unrealistic compared to those found in natural waters (0. 1 to 100 mg/L). To obtain proton binding data for concentrations closer to environmental values, spectroscopic titration methodology is a viable alternative to traditional potentiometric titrations. Spectrophotometric titrations and UV visible spectra of a diluted solution of purified Aldrich humic acid (5 mg(DOC)/L) are used to estimate changes in proton binding moieties as function of pH and ionic strength after calculation of differential absorbance spectra variations. After electrostatic correction of spectrophotometric data, there is a linear operational correlation between spectrophotometric and potentiometric data which can be used as a transfer function between the two properties. Spectrophotometric titrations are then used to determine the changes of humic acid protonation after adsorption onto alpha-alumina. (authors)

  6. Compatible validated spectrofluorimetric and spectrophotometric methods for determination of vildagliptin and saxagliptin by factorial design experiments

    Science.gov (United States)

    Abdel-Aziz, Omar; Ayad, Miriam F.; Tadros, Mariam M.

    2015-04-01

    Simple, selective and reproducible spectrofluorimetric and spectrophotometric methods have been developed for the determination of vildagliptin and saxagliptin in bulk and their pharmaceutical dosage forms. The first proposed spectrofluorimetric method is based on the dansylation reaction of the amino group of vildagliptin with dansyl chloride to form a highly fluorescent product. The formed product was measured spectrofluorimetrically at 455 nm after excitation at 345 nm. Beer's law was obeyed in a concentration range of 100-600 μg ml-1. The second proposed spectrophotometric method is based on the charge transfer complex of saxagliptin with tetrachloro-1,4-benzoquinone (p-chloranil). The formed charge transfer complex was measured spectrophotometrically at 530 nm. Beer's law was obeyed in a concentration range of 100-850 μg ml-1. The third proposed spectrophotometric method is based on the condensation reaction of the primary amino group of saxagliptin with formaldehyde and acetyl acetone to form a yellow colored product known as Hantzsch reaction, measured at 342.5 nm. Beer's law was obeyed in a concentration range of 50-300 μg ml-1. All the variables were studied to optimize the reactions' conditions using factorial design. The developed methods were validated and proved to be specific and accurate for quality control of vildagliptin and saxagliptin in their pharmaceutical dosage forms.

  7. Indications of Segmental Flow in Straight Pipes by Flow Injection with Spectrophotometric Detection

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2000-01-01

    A procedure of spectrophotometric analysis of fluid flow in pipes is described and its performance is tested on three different dye compounds. The procedure follows measurement and mathematical de-convolution of the signal with an exponential function that is associated with molecular diffusion. ...

  8. 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.…

  9. Spectrophotometric study of holmium complexation in KOH solutions at 25 Deg C

    International Nuclear Information System (INIS)

    Stepanchikova, S.A.; Bitejkina, R.P.

    2006-01-01

    Complexation of Ho 3+ in solutions of HoCl 3 and KOH at 25 Deg C is studied by indicator spectrophotometric method. Within the range of pH 9.25-10.10 and μ≤4 x 10 -4 stability constants of Ho 3+ hydroxocomplexes are measured and are extrapolated on zero ion strength [ru

  10. Using Spectrophotometric Titrations To Characterize Humic Acid Reactivity at Environmental Concentrations

    International Nuclear Information System (INIS)

    Janot, N.; Benedetti, M. F.; Janot, N.; Reiller, P. E.; Korshin, G. V.

    2010-01-01

    Potentiometric titration is a common method to characterize dissolved organic matter (DOM) reactivity. Because of the sensitivity of pH electrodes, it is necessary to work with very high DOM (≥1 g/L) concentrations that are unrealistic compared to those found in natural waters (0. 1 to 100 mg/L). To obtain proton binding data for concentrations closer to environmental values, spectroscopic titration methodology is a viable alternative to traditional potentiometric titrations. Spectrophotometric titrations and UV visible spectra of a diluted solution of purified Aldrich humic acid (5 mg(DOC)/L) are used to estimate changes in proton binding moieties as function of pH and ionic strength after calculation of differential absorbance spectra variations. After electrostatic correction of spectrophotometric data, there is a linear operational correlation between spectrophotometric and potentiometric data which can be used as a transfer function between the two properties. Spectrophotometric titrations are then used to determine the changes of humic acid protonation after adsorption onto alpha-alumina. (authors)

  11. Simultaneous Spectrophotometric Determination of Copper, Nickel, and Zinc Using 1-(2-Thiazolylazo)-2-Naphthol in the Presence of Triton X-100 Using Chemometric Methods

    International Nuclear Information System (INIS)

    Low, Kah Hin; Zain, Sharifuddin Md; Abas, Mhd. Radzi; Misran, Misni; Mohd, Mustafa Ali

    2009-01-01

    Multivariate models were developed for the simultaneous spectrophotometric determination of copper (II), nickel (II) and zinc (II) in water with 1-(2-thiazolylazo)-2-naphthol as chromogenic reagent in the presence of Triton X-100. To overcome the drawback of spectral interferences, principal component regression (PCR) and partial least square (PLS) multivariate calibration approaches were applied. Performances were validated with several test sets, and their results were then compared. In general, no significant difference in analytical performance between PLS and PCR models. The root mean square error of prediction (RMSEP) using three components for Cu 2+ , Ni 2+ and Zn 2+ were 0.018, 0.010, 0.011 ppm, respectively. Figures of merit such as sensitivity, analytical sensitivity, limit of detection (LOD) were also estimated. High reliability was achieved when the proposed procedure was applied to simultaneous determination of Cu 2+ , Ni 2+ and Zn 2+ in synthetic mixture and tap water

  12. New Spectrophotometric Methods for the Determination of p ...

    African Journals Online (AJOL)

    derivatizing reagents for the determination of p-aminosalicylic acid (PAS) in tablets. The derivatization was carried ... liquid chromatography (HPLC) [7,8], nuclear magnetic resonance ..... aminosalicylic acid and m-aminophenol by derivative.

  13. Application of rank annihilation factor analysis to the spectrophotometric determination of the formation constant of complex of a new synthesized tripodal ligand with Co2+

    Directory of Open Access Journals (Sweden)

    Reza Golbedaghi

    2017-05-01

    Full Text Available The complex formation between a new synthesized tripodal ligand (L22py and the cation Co2+ in water was studied spectrophotometrically using rank annihilation factor analysis (RAFA. According to molar ratio data the stoichiometry of complexation between the ligand and the cation Co2+ was 1:1. Formation constant of this complex was derived using RAFA on spectrophotometric data. In this process the contribution of ligand is removed from the absorbance data matrix when the complex stability constant acts as an optimizing object and simply combined with the pure spectrum of ligand, the rank of original data matrix can be reduced by one by annihilating the information of the ligand from the original data matrix. The effect of ethanol, dimethylformamide (DMF and acetonitrile (AN was investigated on the formation constant of the Co2+ complex. Complex formation constant in water was estimated as log Kf = 5.09 ± 0.02. In mixtures of solvents of water and DMF and water and AN, the formation constant of the complex was increased because of lowering donor number of the solvent and in mixture of water and ethanol, the complex formation constant was decreased because of lowering of dielectric constant of the solvent.

  14. FRELIB, Failure Reliability Index Calculation

    International Nuclear Information System (INIS)

    Parkinson, D.B.; Oestergaard, C.

    1984-01-01

    1 - Description of problem or function: Calculation of the reliability index given the failure boundary. A linearization point (design point) is found on the failure boundary for a stationary reliability index (min) and a stationary failure probability density function along the failure boundary, provided that the basic variables are normally distributed. 2 - Method of solution: Iteration along the failure boundary which must be specified - together with its partial derivatives with respect to the basic variables - by the user in a subroutine FSUR. 3 - Restrictions on the complexity of the problem: No distribution information included (first-order-second-moment-method). 20 basic variables (could be extended)

  15. Comparison of spectrophotometric and radioisotopic methods for the assay of Rubisco in ozone-treated plants

    International Nuclear Information System (INIS)

    Reid, C.D.; Tissue, D.T.; Fiscus, E.L.; Strain, B.R.

    1997-01-01

    Radioisotopic and spectrophotometric assays for ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) initial and final activities and Rubisco content were compared in plants chronically exposed to ozone (O 3 ) in a greenhouse and the field. In a greenhouse experiment, Glycine max was treated in exposure chambers with either charcoal-filtered air (CF air) or 100 nl O 3 l -1 for 6 h daily during vegetative growth. Samples were collected after 7 days of exposure. In a field experiment, G. max was treated in open-top chambers with either CF air or non-filtered air with O 3 added at 1.5 times ambient O 3 for 12 h daily. Average daily O 3 concentrations were 21 and 92 nl l -1 in the CF and O 3 treatments, respectively. Samples were collected during vegetative and reproductive growth. Both assays generally yielded comparable Rubisco initial and final activities for greenhouse-grown plants regardless of the O 3 treatment. However for field-grown plants, Rubisco initial and final activities average 15 and 23% lower when assayed by the spectrophotometric rather than the radioisotopic method. For Rubisco content estimated by the spectrophotometric method, lower values for the regression of Rubisco activity vs concentration of carboxyarabinitol-1.5-bisphosphate were observed in O 3- than in CF-treated plants. Both assays yielded comparable Rubisco contents in the greenhouse and in the field although the variation was larger with the spectrophotometric method in field-grown plants. Growth conditions, field vs greenhouse, were more critical to the spectrophotometric assay performance than the O 3 treatments for measurement of Rubisco activity and content. (au) 40 refs

  16. AMSAA Reliability Growth Guide

    National Research Council Canada - National Science Library

    Broemm, William

    2000-01-01

    ... has developed reliability growth methodology for all phases of the process, from planning to tracking to projection. The report presents this methodology and associated reliability growth concepts.

  17. A reliability simulation language for reliability analysis

    International Nuclear Information System (INIS)

    Deans, N.D.; Miller, A.J.; Mann, D.P.

    1986-01-01

    The results of work being undertaken to develop a Reliability Description Language (RDL) which will enable reliability analysts to describe complex reliability problems in a simple, clear and unambiguous way are described. Component and system features can be stated in a formal manner and subsequently used, along with control statements to form a structured program. The program can be compiled and executed on a general-purpose computer or special-purpose simulator. (DG)

  18. Spectrophotometric determination of vanadium in environmental and biological samples

    International Nuclear Information System (INIS)

    Rekha, D.; Krishnapriya, B.; Subrahmanyam, P.; Reddyprasad, P.; Dilip Kumar, J.; Chiranjeevi, P.

    2007-01-01

    The method is based on oxidation of p-nitro aniline by vanadium (V) followed by coupling reaction with N-(1-naphthalene-1-y1)ethane-1, 2-diaminedihydrochloride (NEDA) in basic medium of pH 8 to give purple colored derivative. The derivative having an λ max 525nm is stable for 10 days. Beer's law is obeyed for vanadium (V) in the concentration range of 0.03-4.5 μg ml -1 . The proposed method was successfully applied to the analysis of vanadium in environmental and biological samples. (author)

  19. Sensitive spectrophotometric assay of simvastatin in pharmaceuticals using permanganate

    Directory of Open Access Journals (Sweden)

    Kalsang Tharpa

    2010-03-01

    Full Text Available Two simple, sensitive, selective and inexpensive spectrophotometric methods are described for the determination of simvastatin (SMT in bulk drug and in tablets using permanganate as the oxidimetric reagent. In method A, SMT is treated with a measured excess of permanganate in acetic acid medium and the unreacted oxidant is measured at 550 nm, whereas in method B the reaction is carried out in alkaline medium and the resulting manganate is measured at 610 nm. In method A, the amount of permanganate reacted corresponds to the SMT content and the absorbance is found to decrease linearly with the concentration; and in method B, the absorbance increases with concentration. The working conditions of assays were optimized, and the methods were validated according to the current ICH guidelines. Under optimum conditions, SMT could be assayed in the concentration ranges, 1.47 - 17.67x10-5 and 2.27 - 27.18 x10-6 mol/L by method A and method B, respectively. The calculated molar absorptivities are 3.2 x 10³ and 2.5 x 10(4 L/mol/cm for method A and method B, respectively with corresponding Sandell sensitivity values of 0.0387 and 0.0178 μg/cm². The limits of detection (LOD and quantification (LOQ have also been reported. Accuracy and precision for the assay were determined by calculating the intra-day and inter-day at three concentrations; the intra-day RSD was Dois métodos espectrofotométricos simples, sensíveis, seletivos e baratos são descritos para a determinação de sinvastatina (SMT a granel e em comprimidos, utilizando permanganato como reagente oxidimétrico. No método A, a SMT é tratada com excesso conhecido de permanganato em meio de ácido acético e o oxidante que não reage é medido a 550 nm, enquanto no método B, a reação é efetuada em meio alcalino e o manganato resultante é medido a 610 nm. No método A, a quantidade de permanganato que reage corresponde ao conteúdo de SMT e a absorbância diminui linearmente com o aumento da

  20. Multi-wavelength spectrophotometric determination of acidity constant of some newly synthesized Schiff bases and their QSPR study

    Science.gov (United States)

    Hemmateenejad, Bahram; Emami, Leila; Sharghi, Hashem

    2010-01-01

    The acidity constants of some newly synthesized Schiff base derivatives were determined by hard-model based multivariate data analysis of the spectrophotometric data in the course of pH-metric titration in 50% (v/v) methanol-water binary solvent. The employed data analysis method was also able to extract the pure spectra and pH-dependent concentration profiles of the acid-base species. The molecules that possess different substituents (both electron donating and withdrawing) on the ortho-, meta- and para-positions of one of the phenyl ring showed variable acidity constants ranging from 8.77 to 11.07 whereas the parent molecule had an acidity constant of 10.25. To investigate the quantitative effects of changing of substitution pattern on the acidity constant, a quantitative structure-property relation analysis was conducted using substituent constants and molecular descriptor. Some models with high statistical quality (measured by cross-validation Q2) were obtained. It was found that the acidity constant of the studied molecules in the methanol-water mixed solvent not only is affected by electronic features of the solutes but also by the lipophilic interaction between methanol part of solvent and the deprotonated solutes.

  1. Development and validation of a simple spectrophotometric method for the determination of methyldopa in both bulk and marketed dosage formulations

    Directory of Open Access Journals (Sweden)

    Paulo Roberto da Silva Ribeiro

    2014-09-01

    Full Text Available A simple, precise, sensitive, rapid, specific and economical spectrophotometric method was developed to determine methyldopa (MTD content in bulk and pharmaceutical dosage formulations. The proposed method was based on the formation of a colored product from the nitrosation reaction of MTD with sodium nitrite in an acid medium. The resultant nitroso derivative species reacts further with sodium hydroxide and is converted it into a more stable compound. This yellow nitrosation product exhibited an absorption maximum at 430 nm. Beer's Law was obeyed in a concentration range of 6.37 to 82.81 μg mL-1 MTD with an excellent coefficient of determination (R2 = 0.9998. No interference was observed from common excipients in formulations. The results showed the method to be simple, accurate and readily applied for the determination of MTD in pure form and in pharmaceutical preparations. The analytical results obtained for these products using the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at a 95% confidence level.

  2. 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.

  3. Reliability data banks

    International Nuclear Information System (INIS)

    Cannon, A.G.; Bendell, A.

    1991-01-01

    Following an introductory chapter on Reliability, what is it, why it is needed, how it is achieved and measured, the principles of reliability data bases and analysis methodologies are the subject of the next two chapters. Achievements due to the development of data banks are mentioned for different industries in the next chapter, FACTS, a comprehensive information system for industrial safety and reliability data collection in process plants are covered next. CREDO, the Central Reliability Data Organization is described in the next chapter and is indexed separately, as is the chapter on DANTE, the fabrication reliability Data analysis system. Reliability data banks at Electricite de France and IAEA's experience in compiling a generic component reliability data base are also separately indexed. The European reliability data system, ERDS, and the development of a large data bank come next. The last three chapters look at 'Reliability data banks, - friend foe or a waste of time'? and future developments. (UK)

  4. Suncor maintenance and reliability

    Energy Technology Data Exchange (ETDEWEB)

    Little, S. [Suncor Energy, Calgary, AB (Canada)

    2006-07-01

    Fleet maintenance and reliability at Suncor Energy was discussed in this presentation, with reference to Suncor Energy's primary and support equipment fleets. This paper also discussed Suncor Energy's maintenance and reliability standard involving people, processes and technology. An organizational maturity chart that graphed organizational learning against organizational performance was illustrated. The presentation also reviewed the maintenance and reliability framework; maintenance reliability model; the process overview of the maintenance and reliability standard; a process flow chart of maintenance strategies and programs; and an asset reliability improvement process flow chart. An example of an improvement initiative was included, with reference to a shovel reliability review; a dipper trip reliability investigation; bucket related failures by type and frequency; root cause analysis of the reliability process; and additional actions taken. Last, the presentation provided a graph of the results of the improvement initiative and presented the key lessons learned. tabs., figs.

  5. Zeolite - a possible substitute of silica gel in spectrophotometric determination of uranium?

    International Nuclear Information System (INIS)

    Foeldesova, M; Dillinger, P.

    2006-01-01

    Zeolites sorption abilities differ from the ones of the silica gel, which is normally used for uranium determination by spectrophotometric method. The difference is obvious mainly in the case of zeolites chemically modified with 1 or 2 mol/L NaOH solution. Absorbances measured using these zeolites on an radioactive water samples were 4 to 4.2 times bigger than the ones with silica gel. This avoids a use of one universal calibration curve for experimental data evaluation. Within delivered experimental data only a calibration curve for silica gel was provided. Its application to zeolites caused substantial misinterpretation of the results. Calculational construction of individual calibration curves made at this work shaw, that zeolites have a potential to replace the silica gel. This possibility is necessary to confirm by more experiments. Better sorption abilities of the modified zeolites would be utilized to reduce the lower limit for uranium determination by spectrophotometric method. (authors)

  6. Complexation equilibria and spectrophotometric determination of iron(III) with 1-amino-4-hydroxyanthraquinone.

    Science.gov (United States)

    Abu-Bakr, M S; Sedaira, H; Hashem, E Y

    1994-10-01

    The complex equilibria of iron(III) with 1-amino-4-hydroxyanthraquinone (AMHA) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaClO(4)). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance-pH graphs. A simple, rapid, selective and sensitive method for the spectrophotometric determination of trace amounts of Fe(III) is developed based on the formation of Fe(AMHA) complex at pH 2.5 (lambda(max) = 640 nm, epsilon approximately = 2.1 x 10(4) L. mol(-1) . cm(-1)) in the presence of a large number of foreign ions. Interferences caused by palladium(II) was masked by the addition of cyanide ions. The method has been applied to the determination of iron in some synthetic samples and polymetallic iron ores.

  7. Spectrophotometric determination of uranium by previous extraction chromatography separation in polimetalic mineral, phosphorites and technological licours

    International Nuclear Information System (INIS)

    Moreno Bermudez, J.; Cabrera Quevedo, C.; Alfonso Mendez, L.; Rodriguez Aguilera, M.

    1994-01-01

    The development of an analytical procedure for spectrophotometric determination of uranium in polimetalic mineral, phosphorites and technological licours is described. The method is based on the previous separation of interfering elements by extraction chromatography and on spectrophotometric determination of uranium (IV) with arsenazo III in concentrated hydrochloric acid. Tributyl phosphate impregnate on politetrafluoroethylene is used as stationary phase and 5.5 M nitric acid is used as movie phase. The influence of matrix-component elements was studies. The development procedure was applied to real samples, being the results compared with those obtained by other well established analytical methods like gamma-spectrometry, laser fluorimetric, spectrophotometry previous uranium separation by liquid liquid extraction and anion exchange. The reproducibility is evaluated and the detection limited has been established for each studied matrix. A procedure for correcting the thorium interference has been developed for samples with a Th/ 3U8O higher than 0.2

  8. Spectrophotometric determination of metals in Pakistani and foreign brand cigarette tobacco

    International Nuclear Information System (INIS)

    Ikram, M.; Rauf, M.A.; Ali, S.; Iqbal, M.

    2001-01-01

    Tobacco smoking and related uses are major cause of various diseases in human beings. In the present study forty one various brands of cigarettes from Pakistan, United States, United Kingdom and Japan have been selected for determination of iron, nickel and copper spectrophotometrically. The concentration of Fe, Ni and Cu in tobacco of each forty-one brands of national and foreign brands cigarette is given in this article. The spectrophotometric determination of Fe, Ni and Cu in forty one brands of national and foreign cigarettes reveals that the concentrations of these metals depends on different conditions, such as soil condition, fertilizer and sprays during the tobacco growth. However, Cigarette manufacturing companies could have a significant role in their concentration levels. The results obtained by this technique are in good agreement with the reported literature values. (A.B.)

  9. Spectrophotometric method of the determination of gold (III) by using imipramine hydrochloride and promethazine hydrochloride

    International Nuclear Information System (INIS)

    Dembinski, B.; Kurzawa, M.; Szydlowska-Czerniak, A.

    2003-01-01

    Imipramine hydrochloride (IPM.HCl) and promethazine hydrochloride (PMT-HCl) were used for the spectrophotometric determination of gold (III) in the aqueous solution. The halides complexes of gold (III) created a coloured coupling with the studied drugs which were extractable in chloroform. These new compounds were characterized by IR,UV-VIS spectra and thermal and elemental analysis. Rapid and sensitive spectrophotometric method for the determination of gold (III) in the aqueous solution is described. The absorbance was found to be linear function of the gold (III) concentration in the range from 0.2 to 20 x10/sup -1/ mg. The ratio of complex (AuX/sub 4/) to the organic cation from drug in the obtained compounds was determined as 1:1. The method was satisfactorily applied to the analysis of gold (III). A great advantage of the proposed method is that the trace amounts of gold (III) can also be examined. (author)

  10. The analysis of impurities in the diuranate-determination of phosphate by phosphomolybdate blue spectrophotometric method

    International Nuclear Information System (INIS)

    Sun Haobo

    2014-01-01

    Phosphomolybdenum blue spectrophotometric method was used for determination of phosphate in the diuranate. Diuranate was dissolved in nitric acid solution, in which formed a soluble heteropolyacid complex (namely phosphomolybdenum yellow) due to interaction of phosphate and ammonium molybdate. Then phosphomolybdenum yellow was reduced to phosphomolybdenum blue with Bismuth nitrate as catalyst. Colour intensity at 700 nm is in proportion to the content of phosphate determined by spectrophotometric method. This experiment presents good linearity at the range of 30 μg to 245 μg phosphate, and the relative standard deviation of the experimental result is 2.4%, and the recovery rate is from 95% to 105%. The determination result of phosphate content will not be effected under conditions of 4 mg of SiO 2 , 6 mg of Fe, 400 mg of Cl - and 4.5 mg of Ge in the solution. (author)

  11. Evaluation of the Esthetic Properties of Developmental Defects of Enamel: A Spectrophotometric Clinical Study

    Directory of Open Access Journals (Sweden)

    Fabrizio Guerra

    2015-01-01

    Full Text Available Objectives. Detailed clinical quantification of optical properties of developmental defect of enamel is possible with spectrophotometric evaluation. Developmental defects of enamel (DDE are daily encountered in clinical practice. DDE are an alteration in quality and quantity of the enamel, caused by disruption and/or damage to the enamel organ during amelogenesis. Methods. Several clinical indices have been developed to categorize enamel defects based on their nature, appearance, microscopic features, or cause. A sample of 39 permanent teeth presenting DDE on labial surface was examined using the DDE Modified Index and SpectroShade evaluation. The spectrophotometric approach quantifies L* (luminosity, a* (quantity of green-red, and b* (quantity of blue-yellow of different DDE. Conclusions. SpectroShade evaluation of the optical properties of the enamel defect enhances clinical understanding of severity and extent of the defect and characterizes the enamel alteration in terms of color discrepancy and surface characterization.

  12. Estimation of very low concentrations of Ruthenium by spectrophotometric method using barbituric acid as complexing agent

    International Nuclear Information System (INIS)

    Ramakrishna Reddy, S.; Srinivasan, R.; Mallika, C.; Kamachi Mudali, U.; Natarajan, R.

    2012-01-01

    Spectrophotometric method employing numerous chromogenic reagents like thiourea, 1,10-phenanthroline, thiocyanate and tropolone is reported in the literature for the estimation of very low concentrations of Ru. A sensitive spectrophotometric method has been developed for the determination of ruthenium in the concentration range 1.5 to 6.5 ppm in the present work. This method is based on the reaction of ruthenium with barbituric acid to produce ruthenium(ll)tris-violurate, (Ru(H 2 Va) 3 ) -1 complex which gives a stable deep-red coloured solution. The maximum absorption of the complex is at 491 nm due to the inverted t 2g → Π(L-L ligand) electron - transfer transition. The molar absorptivity of the coloured species is 9,851 dm 3 mol -1 cm -1

  13. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  14. Spectrophotometric determination of Fe(II) in Geological Materials by Using Ferrozine as Cromogenic Reagent

    International Nuclear Information System (INIS)

    Sanchez, D. M.; Martin, R.; Marin, J.; Morante, R.; Gutierrez, L.; Bayon, A.

    1999-12-01

    A rapid and sensitive spectrophotometric method for the determination of labile ferrous iron in geological materials is described. Samples are treated by boiling with hydrochloric acid for 60 min. in an atmosphere of carbon dioxide. Systematic erroneous results due to high concentrations of ferric iron are resolved. The limit of detection for the method was 0.02% of FeO. International standard granites analysed by the proposed method showed recoveries ranged from 81-102%. (Author) 9 refs

  15. Spectrophotometric-isotope dilution determination of arsenic in soils and rock

    Science.gov (United States)

    Brown, F.W.; Simon, F.O.; Greenland, L.P.

    1975-01-01

    Arsenic in soil and rock samples may be determined in part-per-million concentrations using a radiochemical-isotope dilution method. Arsenic in the sample plus added As76 tracer is separated as arsine and determined spectrophotometrically as a molybdenum blue complex. The As76 activity in the absorbing solution allows corrections for chemical losses. A lower limit of 1 ppm is determinate in a 0.5-g sample.

  16. Stopped-flow injection spectrophotometric method for determination of chlorate in soil

    OpenAIRE

    Jaroon Jakmunee

    2008-01-01

    A stopped-flow injection (FI) spectrophotometric procedure based on iodometric reaction for the determination of chlorate has been developed. Standard/sample was injected into a stream of potassium iodide solution and then merged with a stream of hydrochloric acid solution to produce triiodide. By stopping the flow while the sample zone is being in a mixing coil, a slow reaction of chlorate with iodide in acidic medium was promoted to proceed with minimal dispersion of the triiodide product z...

  17. Determination of rhenium (7) trace amounts by spectrophotometric titration in medium of mixed solvents

    International Nuclear Information System (INIS)

    Kuznetsov, V.V.; Samorukova, O.L.

    1978-01-01

    The method has been proposed of determining rhenium (7) microamounts by spectrophotometric titration in the medium water-dimethyl-sulphoxide with the reagent nitrochromazo. The method is based on the formation of ionic pairs K + ReO 4 - in water-organic solvents. The results of rhenium determination are satisfactory in a wide concentration range up to 0.3 mkg in 15 ml which makes the method proposed close in sensitivity to photometric methods and much better in reproducibility

  18. Microchemical analysis of materials based on Y-Ba-Cu by spectrophotometric titration

    International Nuclear Information System (INIS)

    Kuznetsov, V.V.; Samorukova, O.L.; Zakharov, Eh.K.

    1990-01-01

    A complex method for analysis of superconductor and similar materials on Y-Ba-Cu basis has been developed, which comprises yttrium and copper determination by their indicator spectrophotometric titration by EDTA and/or complexone 4 in the presence of arsenazo 3. The use of complexone 4 is more favourable. Titration is carried out at λ=650 nm. The method has a sufficient accuracy, provides for rapid determination and does not reguire preliminary separation of components

  19. DETERMINATION OF PROTOPINE IN FUMARIA DENSIFLORA DC. BY TLC- DENSITOMETRIC AND SPECTROPHOTOMETRIC METHOD

    OpenAIRE

    FAFAL, Tuğçe; ÖNÜR, Mustafa Ali

    2007-01-01

    The isoquinoline alkaloid protopine in Fumaria densiflora DC. (Fumariaceae) was quantitatively determined by TLC-densitometry and spectrophotometry. In TLC-densitometry two different solvent systems as toluene : chloroform : methanol : % 25 ammonium hydroxide (5:3:1:1) and cyclohexane : diethylamine (9:1) were used and protopine was detected as 0.351 and 0.352 % respectively. The content of protopine in Fumaria densiflora DC. was estimated as 0.366 % in spectrophotometric method. The quantita...

  20. SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS ESTIMATION OF TOLPERISONE HYDROCHLORIDE AND DICLOFENAC SODIUM IN SYNTHETIC MIXTURE

    OpenAIRE

    Patel Satish A; Hariyani Kaushik P

    2012-01-01

    The present manuscript describes simple, sensitive, rapid, accurate, precise and economical spectrophotometric method for the simultaneous determination of Diclofenac sodium and Tolperisone hydrochloride in bulk and synthetic mixture. The method is based on the simultaneous equations for analysis of both the drugs using methanol as solvent. Diclofenac sodium has absorbance maxima at 281 nm and Tolperisone hydrochloride has absorbance maxima at 255 nm in methanol. The linearity was obtained in...

  1. SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS ESTIMATION OF EPERISONE HYDROCHLORIDE AND DICLOFENAC SODIUM IN SYNTHETIC MIXTURE

    OpenAIRE

    Patel Paresh U; Patel Sejal K; Patel Umang J

    2012-01-01

    The present manuscript describes simple, sensitive, rapid, accurate, precise and economical spectrophotometric method for the simultaneous determination of diclofenac sodium and Eperisone hydrochloride in bulk and synthetic mixture. The method is based on the simultaneous equations for analysis of both the drugs using methanol as solvent. Diclofenac sodium has absorbance maxima at 281 nm and Eperisone hydrochloride has absorbance maxima at 255 nm in methanol. The linearity was obtained in the...

  2. Spectrophotometric determination of silica in water. Low range; Determinacion espectrofotometrica de silicio en aguas. Rango bajo

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: eal@nuclear.inin.mx

    1992-07-15

    The spectrophotometric method for the determination of the silica element in water, demineralized water, raw waters, laundry waters, waters treated with ion exchange resins and sea waters is described. This method covers the determination of the silica element in the interval from 20 to 1000 {mu}g/l on 50 ml. of base sample. These limits its can be variable if the size of the used aliquot one is changed for the final determination of the silica element. (Author)

  3. Spectrophotometric determination of plutonium with chlorophosphonazo III in n-pentanol

    International Nuclear Information System (INIS)

    Saponara, N.M.; Marsh, S.F.

    1982-03-01

    Microgram amounts of plutonium are measured spectrophotometrically as the plutonium-chlorophosphonazo III complex after extraction into n-pentanol from 1.5 M HCl. The relative standard deviation is 1.5% for the range of 2.5 to 17.5 μg. The tolerance is excellent for many metals and nonmetals present in nuclear fuel-cycle materials. A preceding anion-exchange-column separation increases tolerance for certain metals and nonmetals

  4. Spectrophotometric and spectrofluorometric determination of uranium using a flotation process with benzoate and rivanol

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Herroz, C.; Hernandez, M.; Sanchez-Pedreno, C.

    1988-01-01

    Tribenzouranyl anion forms with rivnol an ion-association compound which is floated with isopropyl ether and dissolved in ethanol. As a consequence, new spectrophotometric and spectrofluorimetric methods for the determination of trace amounts of uranium are developed. At 373 nm Beer's law is obeyed over the range 10-150 /mu/g of uranium. When the spectrofluorimetric technique is used, calibration graph is linear in the 2-25 /mu/g range.

  5. Purohit's spectrophotometric method for determination of stability constants of complexes using Job's curves

    International Nuclear Information System (INIS)

    Purohit, D.N.; Goswami, A.K.; Chauhan, R.S.; Ressalan, S.

    1999-01-01

    A spectrophotometric method for determination of stability constants making use of Job's curves has been developed. Using this method stability constants of Zn(II), Cd(II), Mo(VI) and V(V) complexes of hydroxytriazenes have been determined. For the sake of comparison, values of the stability constants were also determined using Harvey and Manning's method. The values of the stability constants developed by two methods compare well. This new method has been named as Purohit's method. (author)

  6. Reliability Based Optimization of Structural Systems

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    1987-01-01

    The optimization problem to design structural systems such that the reliability is satisfactory during the whole lifetime of the structure is considered in this paper. Some of the quantities modelling the loads and the strength of the structure are modelled as random variables. The reliability...... is estimated using first. order reliability methods ( FORM ). The design problem is formulated as the optimization problem to minimize a given cost function such that the reliability of the single elements satisfies given requirements or such that the systems reliability satisfies a given requirement....... For these optimization problems it is described how a sensitivity analysis can be performed. Next, new optimization procedures to solve the optimization problems are presented. Two of these procedures solve the system reliability based optimization problem sequentially using quasi-analytical derivatives. Finally...

  7. Spectrophotometric studies of transcurium element halides and oxyhalides in the solid state

    International Nuclear Information System (INIS)

    Young, J.P.; Haire, R.G.; Fellows, R. L.; Peterson, J.R.

    1978-01-01

    The present state of a microscale spectrophotometric technique is described. The application of spectrophotometry to transcurium elements (Bk, Cf, Es) requires some rather specialized microtechniques for the following reasons: only small amounts of these elements are available; their radioactivity makes the use of μg-sized samples desirable; and spectral study of solids requires thin samples. A schematic diagram of the microscope-spectrophotometer used for spectrophotometric study of the transcurium element compounds is shown. The spectrophotometer, of local design, consists of two microscopes equipped with Cassegrainian reflecting microscope objective lenses, a quartz field lens, and a Jarrell Ash 1/2 meter scanning monochromator equipped with a 1180 line/mm grating blazed at 4000 A. The photomultiplier used in this system is an S-1 type RCA 7102 operated at approximately -50 deg C. This grating-photomultiplier combination provides a continuous response free of discontinuities over the useful wavelength range of the system from 3000 to 11 000 A. The microscope-spectrophotometer is a single beam instrument. Each spectral trace is registered as photomultiplier current on a strip chart recorder. In order to obtain true absorption spectra, however, the output from the photometer is also simultaneously digitized for on-line processing. The unique advantages of applying both spectrophotometric and X-ray powder diffraction methods on the sample, in order to identify and characterize newly synthesized compounds, are also discussed. (T.G.)

  8. Spectrophotometric titrations: Application to the determination of some elements in uranium solutions

    International Nuclear Information System (INIS)

    L'Her, M.

    1967-01-01

    The aim of this work is the application of spectrophotometric titrations to the analysis of uranium-containing solutions. We have been led to examine the general principles involved in these titrations, and we give a brief outline of these principles. In the first part we deal therefore with spectrophotometric titrations from a general point of view, examining their fundamental principle, their practical execution as well as the various possibilities of the method. The advantage of the titration are examined, in particular that of lending itself simultaneous determination of two species. The possibility of applying these spectrophotometric titrations to the analysis of uranium-containing solutions is the subject of the second part of this report: the dosage of a few species in uranium (VI) solutions is described. To this second part is added an experimental appendix consisting of a description of the apparatus, as well as of the operational techniques used for certain titrations, in particular those involving solutions containing uranium. (author) [fr

  9. 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

  10. Spectrophotometric determination of Sn+2 in lyophilized kit for labeling with 99mTc

    International Nuclear Information System (INIS)

    Araujo, Elaine Bortoleti; Sampel, Carolina Judith; Melo, Ivani Bortoleti; Okamoto, Miriam R.Y; Silva, Constancia P.G

    2004-01-01

    The preparation of 99 mTc labeled radiopharmaceuticals depends on the reduction of the technetium pertechnetate, commonly by stannous chloride (SnCl 2 ). The determination of the Sn +2 contents in the lyophilized preparations represents an important quality control procedure that may be applied to the process and to the final product. The objective os this work is the optimization of an spectrophotometric assay to the determination os Sn +2 contents in a citrate-stannous lyophilized kit for 99 mTc labeling. The spectrophotometric methodology employed is based in the colour development when Sn +2 reacts with sodium molybdate in the presence of potasium thiocyanate in chloridric medium. The colourfull reaction studied showed high stability after 60 minutes of the mixtures preparation. The sequence of reagents introduction in the reaction mixture was determinant to the assay. The molibdenium-stannous-tiocianate sequence produces calibration curves with good correlations (R2 ≥ 0.99). The concentrations of the molibdenium solution was also studied, in order to determine a ideal concentration for the Sn +2 range. The spectrophotometric method studied was usefull to the determination of Sn +2 content in different batches of citrate-stannous preparations. The method was fast and easy and can be applied to different stages of the production process, in order to guarantee the content of Sn +2 in the preparations (Au)

  11. Human Reliability Program Overview

    Energy Technology Data Exchange (ETDEWEB)

    Bodin, Michael

    2012-09-25

    This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.

  12. Reliability of software

    International Nuclear Information System (INIS)

    Kopetz, H.

    1980-01-01

    Common factors and differences in the reliability of hardware and software; reliability increase by means of methods of software redundancy. Maintenance of software for long term operating behavior. (HP) [de

  13. Development and validation of RP-HPLC and UV-spectrophotometric methods for rapid simultaneous estimation of amlodipine and benazepril in pure and fixed dose combination

    Directory of Open Access Journals (Sweden)

    Abhi Kavathia

    2017-05-01

    Full Text Available High-performance liquid chromatographic (HPLC and UV spectrophotometric methods were developed and validated for the quantitative determination of amlodipine besylate (AM and benazepril hydrochloride (BZ. Different analytical performance parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD and limit of quantification (LOQ were determined according to International Conference on Harmonization ICH Q2B guidelines. The RP-HPLC method was developed by the isocratic technique on a reversed-phase Shodex C-18 5e column. The retention time for AM and BZ was 4.43 min and 5.70 min respectively. The UV spectrophotometric determinations were performed at 237 nm and 366 nm for AM and at 237 nm for BZ. Correlation between absorbance of AM at 237 nm and 366 nm was established and based on developed correlation equation estimation of BZ at 237 nm was carried out. The linearity of the calibration curves for each analyte in the desired concentration range was good (r2 > 0.999 by both the HPLC and UV methods. The method showed good reproducibility and recovery with percent relative standard deviation less than 5%. Moreover, the accuracy and precision obtained with HPLC co-related well with the UV method which implied that UV spectroscopy can be a cheap, reliable and less time consuming alternative for chromatographic analysis. The proposed methods are highly sensitive, precise and accurate and hence successfully applied for determining the assay and in vitro dissolution of a marketed formulation.

  14. Microwave-assisted of dispersive liquid-liquid microextraction and spectrophotometric determination of uranium after optimization based on Box-Behnken design and chemometrics methods

    Science.gov (United States)

    Niazi, Ali; Khorshidi, Neda; Ghaemmaghami, Pegah

    2015-01-01

    In this study an analytical procedure based on microwave-assisted dispersive liquid-liquid microextraction (MA-DLLME) and spectrophotometric coupled with chemometrics methods is proposed to determine uranium. In the proposed method, 4-(2-pyridylazo) resorcinol (PAR) is used as a chelating agent, and chloroform and ethanol are selected as extraction and dispersive solvent. The optimization strategy is carried out by using two level full factorial designs. Results of the two level full factorial design (24) based on an analysis of variance demonstrated that the pH, concentration of PAR, amount of dispersive and extraction solvents are statistically significant. Optimal condition for three variables: pH, concentration of PAR, amount of dispersive and extraction solvents are obtained by using Box-Behnken design. Under the optimum conditions, the calibration graphs are linear in the range of 20.0-350.0 ng mL-1 with detection limit of 6.7 ng mL-1 (3δB/slope) and the enrichment factor of this method for uranium reached at 135. The relative standard deviation (R.S.D.) is 1.64% (n = 7, c = 50 ng mL-1). The partial least squares (PLS) modeling was used for multivariate calibration of the spectrophotometric data. The orthogonal signal correction (OSC) was used for preprocessing of data matrices and the prediction results of model, with and without using OSC, were statistically compared. MA-DLLME-OSC-PLS method was presented for the first time in this study. The root mean squares error of prediction (RMSEP) for uranium determination using PLS and OSC-PLS models were 4.63 and 0.98, respectively. This procedure allows the determination of uranium synthesis and real samples such as waste water with good reliability of the determination.

  15. Microwave-assisted of dispersive liquid-liquid microextraction and spectrophotometric determination of uranium after optimization based on Box-Behnken design and chemometrics methods.

    Science.gov (United States)

    Niazi, Ali; Khorshidi, Neda; Ghaemmaghami, Pegah

    2015-01-25

    In this study an analytical procedure based on microwave-assisted dispersive liquid-liquid microextraction (MA-DLLME) and spectrophotometric coupled with chemometrics methods is proposed to determine uranium. In the proposed method, 4-(2-pyridylazo) resorcinol (PAR) is used as a chelating agent, and chloroform and ethanol are selected as extraction and dispersive solvent. The optimization strategy is carried out by using two level full factorial designs. Results of the two level full factorial design (2(4)) based on an analysis of variance demonstrated that the pH, concentration of PAR, amount of dispersive and extraction solvents are statistically significant. Optimal condition for three variables: pH, concentration of PAR, amount of dispersive and extraction solvents are obtained by using Box-Behnken design. Under the optimum conditions, the calibration graphs are linear in the range of 20.0-350.0 ng mL(-1) with detection limit of 6.7 ng mL(-1) (3δB/slope) and the enrichment factor of this method for uranium reached at 135. The relative standard deviation (R.S.D.) is 1.64% (n=7, c=50 ng mL(-1)). The partial least squares (PLS) modeling was used for multivariate calibration of the spectrophotometric data. The orthogonal signal correction (OSC) was used for preprocessing of data matrices and the prediction results of model, with and without using OSC, were statistically compared. MA-DLLME-OSC-PLS method was presented for the first time in this study. The root mean squares error of prediction (RMSEP) for uranium determination using PLS and OSC-PLS models were 4.63 and 0.98, respectively. This procedure allows the determination of uranium synthesis and real samples such as waste water with good reliability of the determination. Copyright © 2014. Published by Elsevier B.V.

  16. Spectrophotometric and chemometric methods for determination of imipenem, ciprofloxacin hydrochloride, dexamethasone sodium phosphate, paracetamol and cilastatin sodium in human urine

    Science.gov (United States)

    El-Kosasy, A. M.; Abdel-Aziz, Omar; Magdy, N.; El Zahar, N. M.

    2016-03-01

    New accurate, sensitive and selective spectrophotometric and chemometric methods were developed and subsequently validated for determination of Imipenem (IMP), ciprofloxacin hydrochloride (CIPRO), dexamethasone sodium phosphate (DEX), paracetamol (PAR) and cilastatin sodium (CIL) in human urine. These methods include a new derivative ratio method, namely extended derivative ratio (EDR), principal component regression (PCR) and partial least-squares (PLS) methods. A novel EDR method was developed for the determination of these drugs, where each component in the mixture was determined by using a mixture of the other four components as divisor. Peak amplitudes were recorded at 293.0 nm, 284.0 nm, 276.0 nm, 257.0 nm and 221.0 nm within linear concentration ranges 3.00-45.00, 1.00-15.00, 4.00-40.00, 1.50-25.00 and 4.00-50.00 μg mL- 1 for IMP, CIPRO, DEX, PAR and CIL, respectively. PCR and PLS-2 models were established for simultaneous determination of the studied drugs in the range of 3.00-15.00, 1.00-13.00, 4.00-12.00, 1.50-9.50, and 4.00-12.00 μg mL- 1 for IMP, CIPRO, DEX, PAR and CIL, respectively, by using eighteen mixtures as calibration set and seven mixtures as validation set. The suggested methods were validated according to the International Conference of Harmonization (ICH) guidelines and the results revealed that they were accurate, precise and reproducible. The obtained results were statistically compared with those of the published methods and there was no significant difference.

  17. Reliable Design Versus Trust

    Science.gov (United States)

    Berg, Melanie; LaBel, Kenneth A.

    2016-01-01

    This presentation focuses on reliability and trust for the users portion of the FPGA design flow. It is assumed that the manufacturer prior to hand-off to the user tests FPGA internal components. The objective is to present the challenges of creating reliable and trusted designs. The following will be addressed: What makes a design vulnerable to functional flaws (reliability) or attackers (trust)? What are the challenges for verifying a reliable design versus a trusted design?

  18. Pocket Handbook on Reliability

    Science.gov (United States)

    1975-09-01

    exponencial distributions Weibull distribution, -xtimating reliability, confidence intervals, relia- bility growth, 0. P- curves, Bayesian analysis. 20 A S...introduction for those not familiar with reliability and a good refresher for those who are currently working in the area. LEWIS NERI, CHIEF...includes one or both of the following objectives: a) prediction of the current system reliability, b) projection on the system reliability for someI future

  19. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated......, and as an example the reliability profile and a sensitivity analyses for a corroded reinforced concrete bridge is shown....

  20. Reliability in engineering '87

    International Nuclear Information System (INIS)

    Tuma, M.

    1987-01-01

    The participants heard 51 papers dealing with the reliability of engineering products. Two of the papers were incorporated in INIS, namely ''Reliability comparison of two designs of low pressure regeneration of the 1000 MW unit at the Temelin nuclear power plant'' and ''Use of probability analysis of reliability in designing nuclear power facilities.''(J.B.)

  1. A continuous spectrophotometric assay for monitoring adenosine 5'-monophosphate production.

    Science.gov (United States)

    First, Eric A

    2015-08-15

    A number of biologically important enzymes release adenosine 5'-monophosphate (AMP) as a product, including aminoacyl-tRNA synthetases, cyclic AMP (cAMP) phosphodiesterases, ubiquitin and ubiquitin-like ligases, DNA ligases, coenzyme A (CoA) ligases, polyA deadenylases, and ribonucleases. In contrast to the abundance of assays available for monitoring the conversion of adenosine 5'-triphosphate (ATP) to ADP, there are relatively few assays for monitoring the conversion of ATP (or cAMP) to AMP. In this article, we describe a homogeneous assay that continuously monitors the production of AMP. Specifically, we have coupled the conversion of AMP to inosine 5'-monophosphate (IMP) (by AMP deaminase) to the oxidation of IMP (by IMP dehydrogenase). This results in the reduction of oxidized nicotine adenine dinucleotide (NAD(+)) to reduced nicotine adenine dinucleotide (NADH), allowing AMP formation to be monitored by the change in the absorbance at 340 nm. Changes in AMP concentrations of 5 μM or more can be reliably detected. The ease of use and relatively low expense make the AMP assay suitable for both high-throughput screening and kinetic analyses. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Scaled CMOS Technology Reliability Users Guide

    Science.gov (United States)

    White, Mark

    2010-01-01

    The desire to assess the reliability of emerging scaled microelectronics technologies through faster reliability trials and more accurate acceleration models is the precursor for further research and experimentation in this relevant field. The effect of semiconductor scaling on microelectronics product reliability is an important aspect to the high reliability application user. From the perspective of a customer or user, who in many cases must deal with very limited, if any, manufacturer's reliability data to assess the product for a highly-reliable application, product-level testing is critical in the characterization and reliability assessment of advanced nanometer semiconductor scaling effects on microelectronics reliability. A methodology on how to accomplish this and techniques for deriving the expected product-level reliability on commercial memory products are provided.Competing mechanism theory and the multiple failure mechanism model are applied to the experimental results of scaled SDRAM products. Accelerated stress testing at multiple conditions is applied at the product level of several scaled memory products to assess the performance degradation and product reliability. Acceleration models are derived for each case. For several scaled SDRAM products, retention time degradation is studied and two distinct soft error populations are observed with each technology generation: early breakdown, characterized by randomly distributed weak bits with Weibull slope (beta)=1, and a main population breakdown with an increasing failure rate. Retention time soft error rates are calculated and a multiple failure mechanism acceleration model with parameters is derived for each technology. Defect densities are calculated and reflect a decreasing trend in the percentage of random defective bits for each successive product generation. A normalized soft error failure rate of the memory data retention time in FIT/Gb and FIT/cm2 for several scaled SDRAM generations is

  3. Reliability of provocative tests of motion sickness susceptibility

    Science.gov (United States)

    Calkins, D. S.; Reschke, M. F.; Kennedy, R. S.; Dunlop, W. P.

    1987-01-01

    Test-retest reliability values were derived from motion sickness susceptibility scores obtained from two successive exposures to each of three tests: (1) Coriolis sickness sensitivity test; (2) staircase velocity movement test; and (3) parabolic flight static chair test. The reliability of the three tests ranged from 0.70 to 0.88. Normalizing values from predictors with skewed distributions improved the reliability.

  4. Reliable computer systems.

    Science.gov (United States)

    Wear, L L; Pinkert, J R

    1993-11-01

    In this article, we looked at some decisions that apply to the design of reliable computer systems. We began with a discussion of several terms such as testability, then described some systems that call for highly reliable hardware and software. The article concluded with a discussion of methods that can be used to achieve higher reliability in computer systems. Reliability and fault tolerance in computers probably will continue to grow in importance. As more and more systems are computerized, people will want assurances about the reliability of these systems, and their ability to work properly even when sub-systems fail.

  5. Human factor reliability program

    International Nuclear Information System (INIS)

    Knoblochova, L.

    2017-01-01

    The human factor's reliability program was at Slovenske elektrarne, a.s. (SE) nuclear power plants. introduced as one of the components Initiatives of Excellent Performance in 2011. The initiative's goal was to increase the reliability of both people and facilities, in response to 3 major areas of improvement - Need for improvement of the results, Troubleshooting support, Supporting the achievement of the company's goals. The human agent's reliability program is in practice included: - Tools to prevent human error; - Managerial observation and coaching; - Human factor analysis; -Quick information about the event with a human agent; -Human reliability timeline and performance indicators; - Basic, periodic and extraordinary training in human factor reliability(authors)

  6. Application of Reliability in Breakwater Design

    DEFF Research Database (Denmark)

    Christiani, Erik

    methods to design certain types of breakwaters. Reliability analyses of the main armour and toe berm interaction is exemplified to show the effect of a multiple set of failure mechanisms. First the limit state equations of the main armour and toe interaction are derived from laboratory tests performed...... response, but in one area information has been lacking; bearing capacity has not been treated in depth in a probabilistic manner for breakwaters. Reliability analysis of conventional rubble mound breakwaters and conventional vertical breakwaters is exemplified for the purpose of establishing new ways...... by Bologna University. Thereafter a multiple system of failure for the interaction is established. Relevant stochastic parameters are characterized prior to the reliability evaluation. Application of reliability in crown wall design is illustrated by deriving relevant single foundation failure modes...

  7. On a variant of the first derivative technique in spectrophotometry

    International Nuclear Information System (INIS)

    Kvaratskheli, Yu.K.; Pchelkin, V.A.; Demin, Yu.V.; Kukushkin, G.R.

    1981-01-01

    A variant of the first derivative technique in spectrophotometry is suggested which is based on continuous sinusoidal sweep of the wavelength within a narrow spectral region. A spectrophotometer has been designed which records the first derivative (dA/dlambda). A method has been developed of determining uranium (6) with arsenazo 3 in the presence of 20 times its amounts of zirconium thorium or iron (3). The method can be used for spectrophotometric determination of some other elements with different reagents, particularly in the analysis of elements with overlapped absorption spectra [ru

  8. Spectrophotometric determination of microamounts of boron in water

    International Nuclear Information System (INIS)

    Weber de D'Alessio, Ana; Guido, O.O.; Bandin, N.A.

    1980-01-01

    A fast method of boron in water determination has been studied for the 0.5 .- 2 μg ml -1 concentration range. The procedure is based on the formation of a coloured complex of the tetrafluoroborate of a thionine derivate cation, its extraction by an organic solvent and the further absorptiometric measurement in such media. Methylene blue and azur C were comparatively tested as organic reagents, with 1.2-dichloroethane as the extractant. The absorbance was measured at the maximum (658 nm). The tetrafluoroboric acid formation was reached in 20 min on a water-bath kept at 60 deg C. The sensitivity with methylene blue was higher than with azur C. The molar absorptivities were 65,000 and 38,000 (l mol -1 cm -1 ) respectively. For a boron concentration of 0.1 μg ml -1 the relative standard deviation was 9% for methylene blue and 7% for azur C. The procedure is applicable to the control of boron traces in heavy water of nuclear reactors refrigerating loops. (author) [es

  9. An experimental design approach for optimization of spectrophotometric method for estimation of cefixime trihydrate using ninhydrin as derivatizing reagent in bulk and pharmaceutical formulation

    Directory of Open Access Journals (Sweden)

    Yogita B. Wani

    2017-01-01

    Full Text Available The aim of the present work is to use experimental design to screen and optimize experimental variables for developing a spectrophotometric method for determining cefixime trihydrate content using ninhydrin as a derivatizing reagent. The method is based on the reaction of the amino group of cefixime with ninhydrin in an alkaline medium to form a yellow-colored derivative (λmax 436 nm. A two-level full factorial design was utilized to screen the effect of ninhydrin reagent concentration (X1, volume of ninhydrin reagent (X2, heating temperature (X3 and heating time (X4 on the formation of the cefixime–ninhydrin complex Y (absorbance. One way ANOVA and Pareto ranking analyses have shown that the ninhydrin reagent concentration (X1, volume of ninhydrin reagent (X2 and heating temperature (X3 were statistically significant factors (P < 0.05 affecting the formation of the cefixime–ninhydrin complex Y (absorbance. A Box-Behnken experimental design with response surface methodology was then utilized to evaluate the main, interaction and quadratic effects of these three factors on the selected response. With the help of a response surface plot and contour plot the optimum values of the selected factors were determined and used for further experiments. These values were a ninhydrin reagent concentration (X1 of 0.2% w/v, volume of ninhydrin reagent (X2 of 1 mL and heating temperature (X3 of 80 °C. The proposed method was validated according to the ICH Q2 (R1 method validation guidelines. The results of the present study have clearly shown that an experimental design concept may be effectively applied to the optimization of a spectrophotometric method for estimating the cefixime trihydrate content in bulk and pharmaceutical formulation with the least number of experimental runs possible.

  10. Reliability and safety engineering

    CERN Document Server

    Verma, Ajit Kumar; Karanki, Durga Rao

    2016-01-01

    Reliability and safety are core issues that must be addressed throughout the life cycle of engineering systems. Reliability and Safety Engineering presents an overview of the basic concepts, together with simple and practical illustrations. The authors present reliability terminology in various engineering fields, viz.,electronics engineering, software engineering, mechanical engineering, structural engineering and power systems engineering. The book describes the latest applications in the area of probabilistic safety assessment, such as technical specification optimization, risk monitoring and risk informed in-service inspection. Reliability and safety studies must, inevitably, deal with uncertainty, so the book includes uncertainty propagation methods: Monte Carlo simulation, fuzzy arithmetic, Dempster-Shafer theory and probability bounds. Reliability and Safety Engineering also highlights advances in system reliability and safety assessment including dynamic system modeling and uncertainty management. Cas...

  11. Human reliability analysis

    International Nuclear Information System (INIS)

    Dougherty, E.M.; Fragola, J.R.

    1988-01-01

    The authors present a treatment of human reliability analysis incorporating an introduction to probabilistic risk assessment for nuclear power generating stations. They treat the subject according to the framework established for general systems theory. Draws upon reliability analysis, psychology, human factors engineering, and statistics, integrating elements of these fields within a systems framework. Provides a history of human reliability analysis, and includes examples of the application of the systems approach

  12. Reliability of electronic systems

    International Nuclear Information System (INIS)

    Roca, Jose L.

    2001-01-01

    Reliability techniques have been developed subsequently as a need of the diverse engineering disciplines, nevertheless they are not few those that think they have been work a lot on reliability before the same word was used in the current context. Military, space and nuclear industries were the first ones that have been involved in this topic, however not only in these environments it is that it has been carried out this small great revolution in benefit of the increase of the reliability figures of the products of those industries, but rather it has extended to the whole industry. The fact of the massive production, characteristic of the current industries, drove four decades ago, to the fall of the reliability of its products, on one hand, because the massively itself and, for other, to the recently discovered and even not stabilized industrial techniques. Industry should be changed according to those two new requirements, creating products of medium complexity and assuring an enough reliability appropriated to production costs and controls. Reliability began to be integral part of the manufactured product. Facing this philosophy, the book describes reliability techniques applied to electronics systems and provides a coherent and rigorous framework for these diverse activities providing a unifying scientific basis for the entire subject. It consists of eight chapters plus a lot of statistical tables and an extensive annotated bibliography. Chapters embrace the following topics: 1- Introduction to Reliability; 2- Basic Mathematical Concepts; 3- Catastrophic Failure Models; 4-Parametric Failure Models; 5- Systems Reliability; 6- Reliability in Design and Project; 7- Reliability Tests; 8- Software Reliability. This book is in Spanish language and has a potentially diverse audience as a text book from academic to industrial courses. (author)

  13. Operational safety reliability research

    International Nuclear Information System (INIS)

    Hall, R.E.; Boccio, J.L.

    1986-01-01

    Operating reactor events such as the TMI accident and the Salem automatic-trip failures raised the concern that during a plant's operating lifetime the reliability of systems could degrade from the design level that was considered in the licensing process. To address this concern, NRC is sponsoring the Operational Safety Reliability Research project. The objectives of this project are to identify the essential tasks of a reliability program and to evaluate the effectiveness and attributes of such a reliability program applicable to maintaining an acceptable level of safety during the operating lifetime at the plant

  14. Circuit design for reliability

    CERN Document Server

    Cao, Yu; Wirth, Gilson

    2015-01-01

    This book presents physical understanding, modeling and simulation, on-chip characterization, layout solutions, and design techniques that are effective to enhance the reliability of various circuit units.  The authors provide readers with techniques for state of the art and future technologies, ranging from technology modeling, fault detection and analysis, circuit hardening, and reliability management. Provides comprehensive review on various reliability mechanisms at sub-45nm nodes; Describes practical modeling and characterization techniques for reliability; Includes thorough presentation of robust design techniques for major VLSI design units; Promotes physical understanding with first-principle simulations.

  15. A new optical sensor for spectrophotometric determination of uranium (VI) and thorium (IV) in acidic medium

    Energy Technology Data Exchange (ETDEWEB)

    Elhefnawy, O.A. [Nuclear and Radiological Regulatory Authority (NRRA), Cairo (Egypt). Nuclear Safeguards and Physical Protection Dept.

    2017-07-01

    A spectrophotometric method was developed for U(VI) and Th(IV) determination in acidic medium by using proposed optical sensor. This sensor is base on the complexation reaction of the ionophore midodrine hydrochloride (L) with U(VI)/Th(IV) in plasticized (o-NPOE) high molecular weight (PVC). Several parameters such as effect of acidic medium, response time and sensor compositions were studied. The determination of the complexes stoichiometry was also studied using Job's method. The complexes stoichiometry were measured at the absorbance spectra 302 nm and the results were found to be 1:1 for both complexes U(VI)-L and Th(IV)-L. The complexation reaction was extremely rapid at room temperature; it takes 5, 10 min to complete the complexation reaction in U(VI) and Th(IV), respectively. Under the optimum conditions the calibration curves of U(VI)/Th(IV) determination, have good linearity at different acidic medium nitric, sulfuric, and phosphoric acids with low detection and quantification limits. The accuracy and precision studies proved that the proposed optical sensor is valid and qualified for U(VI)/Th(IV) spectrophotometric determination in different acidic medium. The selectivity of the proposed optical sensor was studied. The proposed optical sensor was applied successfully for U(VI)/Th(IV) determination in research and development (R and D) nuclear waste samples with satisfactory results. A comparative study of the proposed optical sensor with other previous spectrophotometric sensors for U(VI)/Th(IV) determination, proved the high efficiency of the proposed optical sensor, that it presents wide linear range and low detection limit. The proposed optical sensor could be applied for a quantitative determination of U(VI)/Th(IV) in acidic waste samples.

  16. A new optical sensor for spectrophotometric determination of uranium (VI) and thorium (IV) in acidic medium

    International Nuclear Information System (INIS)

    Elhefnawy, O.A.

    2017-01-01

    A spectrophotometric method was developed for U(VI) and Th(IV) determination in acidic medium by using proposed optical sensor. This sensor is base on the complexation reaction of the ionophore midodrine hydrochloride (L) with U(VI)/Th(IV) in plasticized (o-NPOE) high molecular weight (PVC). Several parameters such as effect of acidic medium, response time and sensor compositions were studied. The determination of the complexes stoichiometry was also studied using Job's method. The complexes stoichiometry were measured at the absorbance spectra 302 nm and the results were found to be 1:1 for both complexes U(VI)-L and Th(IV)-L. The complexation reaction was extremely rapid at room temperature; it takes 5, 10 min to complete the complexation reaction in U(VI) and Th(IV), respectively. Under the optimum conditions the calibration curves of U(VI)/Th(IV) determination, have good linearity at different acidic medium nitric, sulfuric, and phosphoric acids with low detection and quantification limits. The accuracy and precision studies proved that the proposed optical sensor is valid and qualified for U(VI)/Th(IV) spectrophotometric determination in different acidic medium. The selectivity of the proposed optical sensor was studied. The proposed optical sensor was applied successfully for U(VI)/Th(IV) determination in research and development (R and D) nuclear waste samples with satisfactory results. A comparative study of the proposed optical sensor with other previous spectrophotometric sensors for U(VI)/Th(IV) determination, proved the high efficiency of the proposed optical sensor, that it presents wide linear range and low detection limit. The proposed optical sensor could be applied for a quantitative determination of U(VI)/Th(IV) in acidic waste samples.

  17. Validated spectrophotometric methods for determination of Alendronate sodium in tablets through nucleophilic aromatic substitution reactions

    Directory of Open Access Journals (Sweden)

    Walash Mohamed I

    2012-04-01

    Full Text Available Abstract Background Alendronate (ALD is a member of the bisphosphonate family which is used for the treatment of osteoporosis, bone metastasis, Paget's disease, hypocalcaemia associated with malignancy and other conditions that feature bone fragility. ALD is a non-chromophoric compound so its determination by conventional spectrophotometric methods is not possible. So two derivatization reactions were proposed for determination of ALD through the reaction with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl and 2,4-dinitrofluorobenzene (DNFB as chromogenic derivatizing reagents. Results Three simple and sensitive spectrophotometric methods are described for the determination of ALD. Method I is based on the reaction of ALD with NBD-Cl. Method II involved heat-catalyzed derivatization of ALD with DNFB, while, Method III is based on micellar-catalyzed reaction of the studied drug with DNFB at room temperature. The reactions products were measured at 472, 378 and 374 nm, for methods I, II and III, respectively. Beer's law was obeyed over the concentration ranges of 1.0-20.0, 4.0-40.0 and 1.5-30.0 μg/mL with lower limits of detection of 0.09, 1.06 and 0.06 μg/mL for Methods I, II and III, respectively. The proposed methods were applied for quantitation of the studied drug in its pure form with mean percentage recoveries of 100.47 ± 1.12, 100.17 ± 1.21 and 99.23 ± 1.26 for Methods I, II and III, respectively. Moreover the proposed methods were successfully applied for determination of ALD in different tablets. Proposals of the reactions pathways have been postulated. Conclusion The proposed spectrophotometric methods provided sensitive, specific and inexpensive analytical procedures for determination of the non-chromophoric drug alendronate either per se or in its tablet dosage forms without interference from common excipients. Graphical abstract

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

    International Nuclear Information System (INIS)

    Parakudyil, A.S.; Pillai, A.K.; Reddy, A.V.R.; Singal, R.K.; Sharma, P.K.; Michael, K.M.

    2012-01-01

    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

  19. Highly sensitive spectrophotometric kinetic determination of vanadium by catalysis of the gallic acid-bromate reaction

    International Nuclear Information System (INIS)

    Fukasawa, Tsutomu; Kawakubo, Susumu; Yamanouchi, Tatsuo

    1985-01-01

    Conditions are described for improving the speed and sensitivity of this catalytic determination of vanadium. The reaction of 0.018 M gallic acid with 0.96 M sodium bromate at pH 3.8 and double-beam spectrophotometric measurement at 380 nm are recommended. The highest practical sensitivity at 22-30 0 C was ca. 40 pg for an absorbance change of 0.0005, 50 times better than previously. The detection limit was ca. 0.5 ng of vanadium. Reaction at 50 0 C gave even better sensitivity. (Auth.)

  20. K4 Fe(CN)6 as a spectrophotometric agent for uranium analysis

    International Nuclear Information System (INIS)

    Soedyartomo; Tarwita.

    1976-01-01

    The properties of K 4 Fe(CN) 6 as a spectrophotometric agent for Uranium analysis was observed by putting some experiment into practice. The experiment covers the observation of expanding colour stability, the optimization of operating condition (p,H. and wavelength), the effect of K 4 Fe(CN) 6 concentration and the preparation of its standard curves (transmitansion vs uranium concentration) and the observation of the interfering metal spectra s (Cu ++ , Fe ++ ) either of its mixtures or themselves alone, has been carried out. The result and discussion on it are given. (author)

  1. Quantization of buspirone hydrochloride in pure and pharmaceutical formulation by spectrophotometric method

    International Nuclear Information System (INIS)

    Kazi, A.A.; Mumtaz, A.; Sabri, M.U.

    2008-01-01

    A simple and sensitive method is described for the determination of bus pirone hydrochloride in bulk drug and in formulations employing spectrophotometric technique. The method is based on the interaction orbuspirone hydrochloride with ammonium molybdate in acidic media and the absorbance is measured at 700 nm. Beer's Law is obeyed in the range of 5 macro g to 350 micro g/ml and RSD is 0.96% for buspirone hydrochloride. Analytical data for the determination of pure compound is presented along with the application of the proposed method for the analysis of pharmaceutical formulation. (author)

  2. Comparison of numerical and physico-chemical models for on-line spectrophotometric control of uranium

    International Nuclear Information System (INIS)

    Corriou, J.P.; Boisde, G.

    1986-04-01

    In view of on-line spectrophotometric control of fuel reprocessing streams, a physico-chemical model able to predict uranium and nitric acid concentrations in an uranyl nitrate-nitric acid system has been searched. Thus the influences of the following parameters: uranium, nitrate, hydrogen ion concentrations, ionic strength, on the equilibria of complexation of uranium (VI) nitrate have been evaluated. Extinction coefficients for the uranium mononitrate and uranium dinitrate complexes are given between 410 and 440 nm. The apparent equilibrium constants are determined as a function of the ionic strength. The limitations of this predictive model are emphasized and comparisons with numerical models are discussed. (16 refs)

  3. Spectrophotometric determination of hydrogen peroxide with osmium(VIII) and m-carboxyphenylfluorone.

    Science.gov (United States)

    Hoshino, Mitsuru; Kamino, Shinichiro; Doi, Mitsunobu; Takada, Shingo; Mitani, Shota; Yanagihara, Rika; Asano, Mamiko; Yamaguchi, Takako; Fujita, Yoshikazu

    2014-01-03

    Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL(-1), with an effective molar absorption coefficient (at 580 nm) of 5.21×10(4) L mol(-1) cm(-1) and a relative standard deviation of 0.33% (n=6). Further, we performed the characterization of MCPF and obtained the crystal structure. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Ultra-violet Spectrophotometric Determination of Caffeine in Soft and Energy Drinks Available in Yenagoa, Nigeria

    OpenAIRE

    Amos-Tautua; W. Bamidele Martin; E.R.E. Diepreye

    2014-01-01

    This study was carried out to determine the pH and levels of caffeine in eight brands of carbonated and energy drinks available in local market in Yenagoa, Nigeria. Quantitative analysis of caffeine was performed by a simple and fast standard UV spectrophotometric method, using carbon tetrachloride as the extracting solvent. Results showed that the pH of the beverages were slightly acidic ranging from 5.92-6.44. The minimum caffeine level was observed in the carbonated soft drink Coca Cola (4...

  5. Development of a new spectrophotometric method to determine the total aromatic contents in kerosene

    International Nuclear Information System (INIS)

    Harfoush, A.; shlewit, H.

    1996-12-01

    This developed spectrophotometric method is helpful to determine and control the total aromatic contents in kerosene, during the treatment process of kerosene with conc. H sup 2 SO sup 4 and P sup 2 O sup 5 to remove aromatics, which have negative effect on the solvent extraction coefficient KD of uranium from the Syrian phosphoric acid, where kerosene is used as diluent. this method is rapid according to others, and simply, using the standard curve prepared by the separated aromatics from the Syrian kerosene, A =f (C) at 272 nm, we can calculate the aromatic contents in the known samples. (author). 24 Refs., 5 Figs

  6. Anion-exchange enrichment and spectrophotometric determination of uranium in sea-water

    International Nuclear Information System (INIS)

    Kuroda, Rokuro; Oguma, Koichi; Mukai, Noriko; Iwamoto, Masatoshi

    1987-01-01

    A method is proposed for the determination of uranium in sea-water. The uranium is strongly sorbed on a strongly basic anion-exchange resin (Cl - form) from acidified sea-water containing sodium azide (0.3M) and is easily eluted with 1M hydrochloric acid. Uranium in the effluent can be determined spectrophotometrically with Arsenazo III. The combined method allows easy and selective determination of uranium in sea-water without using a sophisticated adsorbent. The overall recovery and precision are satisfactory at the 3 μg/1. level. (author)

  7. Spectrophotometric activity microassay for pure and recombinant cytochrome P450-type nitric oxide reductase

    CSIR Research Space (South Africa)

    Garny, S

    2014-02-01

    Full Text Available spectrophotometric quantification of NADH [19]. Kaya et al. (2004) [19] demonstrated the linearly proportional relationship between the oxidation of NADH to NAD+, with the release of NO from NOC-5, but did not develop a kinetic assay for NOR activity using... this principle, the primary aim of this study. Nakahara et al. (1993) [10] determined the stoichiometry of NO reduction by NOR as 2:1:1 for NO:NADH:N2O. Therefore, for each NADH oxidized to NAD+, two molecules of NO are converted to N2O (refer Equation 1). 2...

  8. Determination of niobium in rocks by an isotope dilution spectrophotometric method

    Science.gov (United States)

    Greenland, L.P.; Campbell, E.Y.

    1970-01-01

    Rocks and minerals are fused with sodium peroxide in the presence of carrierfree 95Nb. The fusion cake is leached with water and the precipitate dissolved in hydrofluoric-sulfuric acid mixture. Niobium is extracted into methyl isobutyl ketone and further purified by ion exchange. The amount of niobium is determined spectrophotometrically with 4-(2-pyridylazo)-resorcinol, and the chemical yield of the separations determined by counting 95Nb. This procedure is faster and less sensitive to interferences than previously proposed methods for determining niobium in rocks.The high purity of the separated niobium makes the method applicable to nearly all matrices. ?? 1970.

  9. Oxytetracycline as a new analytical reagent for the spectrophotometric determination of boron

    Energy Technology Data Exchange (ETDEWEB)

    Narayana, G L

    1984-05-01

    Oxytetracycline hydrochloride, Terramycin, is introduced as a new reagent for the spectrophotometric determination of trace quantities of boron in concentrated sulphuric acid medium. The reagent has an absorption maximum at 430 nm, and that of the boron complex at 520 nm. The colored system conformed to Beer's law between 2 and 10 ..mu..g of boron at 520 nm. The molar absorptivity calculated on the basis of boron is 10,800 1 mol/sup -1/ cm/sup -1/. The composition of the complex has been shown to be 1:1 both by the slope ratio and molar ratio methods. 16 references.

  10. Oxytetracycline as a new analytical reagent for the spectrophotometric determination of boron

    International Nuclear Information System (INIS)

    Narayana, G.L.

    1984-01-01

    Oxytetracycline hydrochloride, Terramycin, is introduced as a new reagent for the spectrophotometric determination of trace quantities of boron in concentrated sulphuric acid medium. The reagent has an absorption maximum at 430 nm, and that of the boron complex at 520 nm. The coloured system conformed to Beer's law between 2 and 10 μg of boron at 520 nm. The molar absorptivity calculated on the basis of boron is 10,800 1 mol -1 cm -1 . The composition of the complex has been shown to be 1:1 both by the slope ratio and molar ratio methods. (author)

  11. Liquid chromatographic and spectrophotometric methods for the determination of erythromycin stearate and trimethoprim in tablets

    OpenAIRE

    Hassib, Sonia T.; Farag, Awatef E.; Elkady, Ehab F.

    2011-01-01

    Simple, accurate and precise reversed-phase liquid chromatographic (LC) and spectrophotometric methods have been developed and validated for the determination of erythromycin stearate (ERS) and trimethoprim (TMP) in mixture. In LC method, chromatographic separation was achieved on a Symmetry® Waters C18 column (150 × 4.6 mm, 5 μm) based on isocratic elution using a mobile phase consisting of potassium dihydrogen phosphate buffer pH (9):acetonitrile:water (25:100:50, v/v/v) at a flow rate of 1...

  12. Spectrophotometric determination of phosphorus in iron alloys employing a flow injection system

    OpenAIRE

    Gervasio,Ana P. G.; Miranda,Carlos E. S.; Luca,Gilmara C.; Tumang,Cristiane A.; Campos,Luis F. P.; Reis,Boaventura F.

    2001-01-01

    A flow-injection procedure for spectrophotometric determination of phosphorus in electrolytic iron and iron alloys is proposed. The method is based on the ammonium molybdate reaction followed by stannous chloride reduction in acidic medium. In order to circumvent the severe interference caused by the major constituents such as Fe(III) and Cr(III), a mini-column packed with AG50W-X8 resin was coupled to the manifold. A sample throughput of 40 determinations per hour, a dynamical range from P 0...

  13. Potentiometric and spectrophotometric titration study of interaction of tungstovanadophosphoric heteropolyacids with sodium hydroxide

    International Nuclear Information System (INIS)

    Borkoyakov, S.A.; Fisun, L.A.

    1988-01-01

    The methods of potentiometric and spectrophotometric titration are used to study H s+n PW 12-n V n O 40 (n=1,2) (P-W-V HPA) decomposition by sodium hydroxide. It is shown that at the first stage of heteropolyanion interaction with alkali (pH) > 4 P-W-V HPA structural reconstruction takes place. It is accompanied by the formation of complexes with a higher content of vanadium atoms stable at pH 4-7/ P-W-V HPA decomposition to initial salts occurs at pH > 8

  14. 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

  15. 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.

  16. Spectrophotometric determination of trace uranium in phosphate ore samples from kurum and uro areas, Nuba mountains, Sudan

    International Nuclear Information System (INIS)

    Mohamed, A. A.; Ali, A. H.; Altayeb, M. A. H.

    2004-01-01

    A method was proposed for the spectrophotometric determination of uranium content in phosphate ores. the method is based on the use of nitrogen (v) acid for leaching the rock, and treatment with ammonium carbonate solution, whereby uranium (Vi) is kept in solution as its carbonate complex. The ion-exchange technique was used for the recovery of uranium. Uranium was determined spectrophotometrically by measurement of the absorbance of the yellow uranium (Vi)-8-hydroxyquinolate complex at λ 425 nm. The procedure was used for the determination of trace uranium content in 30 phosphate ore samples collected from Kurun and Uro areas in Nuba mountains in Sudan. X-ray fluorescence technique was employed for the assessment of the method used. The spectrophotometric method results show a high similarity with those obtained by XRF technique. This agreement indicates that the procedure proposed here has been successfully applied for the determination of uranium in phosphate ores. (Author)

  17. Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

    Energy Technology Data Exchange (ETDEWEB)

    Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R. [Water Studies Centre, School of Chemistry, Monash University, Victoria 3800 (Australia); McKelvie, Ian D., E-mail: iandm@unimelb.edu.au [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2011-10-17

    Highlights: {yields} Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. {yields} A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. {yields} Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. {yields} Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. {yields} This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L{sup -1}, 0.4%RSD (1 mg N L{sup -1} as nitrate, n = 10), a coefficient of determination (R{sup 2}) of 0.9995 over the calibration range 0.0-2.0 mg N L{sup -1}, and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L{sup -1}, 1%RSD (1 mg N L{sup -1} as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L{sup -1}, and a throughput of 5 sample h{sup -1} measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column

  18. Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

    International Nuclear Information System (INIS)

    Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R.; McKelvie, Ian D.

    2011-01-01

    Highlights: → Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. → A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. → Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. → Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. → This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L -1 , 0.4%RSD (1 mg N L -1 as nitrate, n = 10), a coefficient of determination (R 2 ) of 0.9995 over the calibration range 0.0-2.0 mg N L -1 , and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L -1 , 1%RSD (1 mg N L -1 as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L -1 , and a throughput of 5 sample h -1 measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column. The overlap of chloride and nitrate spectra in seawater is

  19. Hawaii Electric System Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Loose, Verne William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Silva Monroy, Cesar Augusto [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-08-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers’ views of reliability “worth” and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers’ views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  20. Hawaii electric system reliability.

    Energy Technology Data Exchange (ETDEWEB)

    Silva Monroy, Cesar Augusto; Loose, Verne William

    2012-09-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  1. Improving machinery reliability

    CERN Document Server

    Bloch, Heinz P

    1998-01-01

    This totally revised, updated and expanded edition provides proven techniques and procedures that extend machinery life, reduce maintenance costs, and achieve optimum machinery reliability. This essential text clearly describes the reliability improvement and failure avoidance steps practiced by best-of-class process plants in the U.S. and Europe.

  2. LED system reliability

    NARCIS (Netherlands)

    Driel, W.D. van; Yuan, C.A.; Koh, S.; Zhang, G.Q.

    2011-01-01

    This paper presents our effort to predict the system reliability of Solid State Lighting (SSL) applications. A SSL system is composed of a LED engine with micro-electronic driver(s) that supplies power to the optic design. Knowledge of system level reliability is not only a challenging scientific

  3. Integrated system reliability analysis

    DEFF Research Database (Denmark)

    Gintautas, Tomas; Sørensen, John Dalsgaard

    Specific targets: 1) The report shall describe the state of the art of reliability and risk-based assessment of wind turbine components. 2) Development of methodology for reliability and risk-based assessment of the wind turbine at system level. 3) Describe quantitative and qualitative measures...

  4. Reliability of neural encoding

    DEFF Research Database (Denmark)

    Alstrøm, Preben; Beierholm, Ulrik; Nielsen, Carsten Dahl

    2002-01-01

    The reliability with which a neuron is able to create the same firing pattern when presented with the same stimulus is of critical importance to the understanding of neuronal information processing. We show that reliability is closely related to the process of phaselocking. Experimental results f...

  5. Design reliability engineering

    International Nuclear Information System (INIS)

    Buden, D.; Hunt, R.N.M.

    1989-01-01

    Improved design techniques are needed to achieve high reliability at minimum cost. This is especially true of space systems where lifetimes of many years without maintenance are needed and severe mass limitations exist. Reliability must be designed into these systems from the start. Techniques are now being explored to structure a formal design process that will be more complete and less expensive. The intent is to integrate the best features of design, reliability analysis, and expert systems to design highly reliable systems to meet stressing needs. Taken into account are the large uncertainties that exist in materials, design models, and fabrication techniques. Expert systems are a convenient method to integrate into the design process a complete definition of all elements that should be considered and an opportunity to integrate the design process with reliability, safety, test engineering, maintenance and operator training. 1 fig

  6. Bayesian methods in reliability

    Science.gov (United States)

    Sander, P.; Badoux, R.

    1991-11-01

    The present proceedings from a course on Bayesian methods in reliability encompasses Bayesian statistical methods and their computational implementation, models for analyzing censored data from nonrepairable systems, the traits of repairable systems and growth models, the use of expert judgment, and a review of the problem of forecasting software reliability. Specific issues addressed include the use of Bayesian methods to estimate the leak rate of a gas pipeline, approximate analyses under great prior uncertainty, reliability estimation techniques, and a nonhomogeneous Poisson process. Also addressed are the calibration sets and seed variables of expert judgment systems for risk assessment, experimental illustrations of the use of expert judgment for reliability testing, and analyses of the predictive quality of software-reliability growth models such as the Weibull order statistics.

  7. Investigating Reliabilities of Intraindividual Variability Indicators

    Science.gov (United States)

    Wang, Lijuan; Grimm, Kevin J.

    2012-01-01

    Reliabilities of the two most widely used intraindividual variability indicators, "ISD[superscript 2]" and "ISD", are derived analytically. Both are functions of the sizes of the first and second moments of true intraindividual variability, the size of the measurement error variance, and the number of assessments within a burst. For comparison,…

  8. Neutron logging reliability techniques and apparatus

    International Nuclear Information System (INIS)

    Johnstone, C.W.

    1978-01-01

    This invention relates in general to neutron logging of earth formations, and in particular, to novel apparatus and procedures for determining the validity, or reliability, of data derived at least in part by logging neutron characteristics of earth formations and, if desired, for affording verifiably accurate indications of such data

  9. Neutron logging reliability techniques and apparatus

    International Nuclear Information System (INIS)

    Johnstone, C.W.

    1974-01-01

    This invention relates in general to neutron logging of earth formations, and in particular, to novel apparatus and procedures for determining the validity, or reliability, of data derived at least in part by logging neutron characteristics of earth formations and, if desired, for affording verifiably accurate indications of such data. (author)

  10. Development and Validation of Spectrophotometric Methods for the Determination of Rasagiline in Pharmaceutical Preparations

    Directory of Open Access Journals (Sweden)

    Serife Evrim Kepekci Tekkeli

    2013-01-01

    Full Text Available This study presents three simple, rapid, and accurate spectrophotometric methods for the determination of Rasagiline (RSG in pharmaceutical preparations. The determination procedures depend on the reaction of RSG with chloranilic acid for method A, tetrachloro-1,4-benzoquinone for method B, and 7,7,8,8-tetracyanoquinodimethane for method C. The colored products were quantitated spectrophotometrically at 524, 535, and 843 nm for methods A, B, and C, respectively. Different variables affecting the reaction were optimized. Linearity ranges of the methods with good correlation coefficients (0.9988–0.9996 were observed as 25–300 µg mL−1, 25–350 µg mL−1, and 50–500 µg mL−1 for methods A, B, and C, respectively. The formation of products takes place through different mechanisms. The sites of interaction were confirmed by elemental analysis using IR and 1H-NMR spectroscopy. The validation of the methods was carried out in terms of specificity, linearity, accuracy, precision, robustness, limit of detection, and limit of quantitation. No interference was observed from concomitants usually present in dosage forms. The methods were applied successfully to the determination of RSG in pharmaceutical preparations.

  11. Stopped-flow injection spectrophotometric method for determination of chlorate in soil

    Directory of Open Access Journals (Sweden)

    Jaroon Jakmunee

    2008-06-01

    Full Text Available A stopped-flow injection (FI spectrophotometric procedure based on iodometric reaction for the determination of chlorate has been developed. Standard/sample was injected into a stream of potassium iodide solution and then merged with a stream of hydrochloric acid solution to produce triiodide. By stopping the flow while the sample zone is being in a mixing coil, a slow reaction of chlorate with iodide in acidic medium was promoted to proceed with minimal dispersion of the triiodide product zone. When the flow started again, a concentrated product zone was pushed into a flow cell and a signal profile due to light absorption of the product was recorded. Employing a lab-built semi-automatic stopped-FI analyser, the analysis can be performed with higher degree of automation and low chemical consumption. Linear calibration graph in the range of 5-50 mg ClO3- L-1 was obtained, with detection limit of 1.4 mg ClO3- L-1. Relative standard deviation of 2.2% (30 mg ClO3- L-1, n=10 and sample throughput of about 20 h-1 were achieved. The system was applied to soil samples and validated by batch spectrophotometric and standard titrimetric methods.

  12. Automated spectrophotometric bicarbonate analysis in duodenal juice compared to the back titration method.

    Science.gov (United States)

    Erchinger, Friedemann; Engjom, Trond; Gudbrandsen, Oddrun Anita; Tjora, Erling; Gilja, Odd H; Dimcevski, Georg

    2016-01-01

    We have recently evaluated a short endoscopic secretin test for exocrine pancreatic function. Bicarbonate concentration in duodenal juice is an important parameter in this test. Measurement of bicarbonate by back titration as the gold standard method is time consuming, expensive and technically difficult, thus a simplified method is warranted. We aimed to evaluate an automated spectrophotometric method in samples spanning the effective range of bicarbonate concentrations in duodenal juice. We also evaluated if freezing of samples before analyses would affect its results. Patients routinely examined with short endoscopic secretin test suspected to have decreased pancreatic function of various reasons were included. Bicarbonate in duodenal juice was quantified by back titration and automatic spectrophotometry. Both fresh and thawed samples were analysed spectrophotometrically. 177 samples from 71 patients were analysed. Correlation coefficient of all measurements was r = 0.98 (p titration gold standard. This is a major simplification of direct pancreas function testing, and allows a wider distribution of bicarbonate testing in duodenal juice. Extreme values for Bicarbonate concentration achieved by the autoanalyser method have to be interpreted with caution. Copyright © 2016 IAP and EPC. Published by Elsevier India Pvt Ltd. All rights reserved.

  13. Ocean Health X-Prize testing of a Simplified Spectrophotometric pH Sensor

    Science.gov (United States)

    Darlington, R. C.; DeGrandpre, M. D.; Spaulding, R. S.; Beck, J. C.

    2016-02-01

    Since the Industrial Revolution, the world's oceans have absorbed increasing amounts of CO2, resulting in a >0.1 reduction in the pH of surface waters. This acidification of the oceans has many far reaching impacts on marine life. There is, therefore, great need of quality instrumentation to assess and follow the changing carbonate system. To address this need, we have developed a simplified spectrophotometric pH sensor with accuracy and precision suitable for sea surface measurements with special emphasis on reduced size and cost. The reduced size will allow deployment of sensors on a much wider variety of platforms than are currently possible, and the reduced cost will make the instruments available to a broader research community. This prototype pH instrument was entered into the Wendy Schmidt Ocean Health X-Prize, an incentivized global competition to spur innovation in sensors to monitor ocean acidification's impact on marine ecosystems. Results from the three phases of competition which explored accuracy, precision, and stability culminating in a one month field trial are detailed. The prototype proved to be highly accurate (+/-0.009), with good precision (+/-0.004) and stability showing drift indistinguishable from that of the validation measurements. The innovations that enabled this sensor to succeed in the competition could allow for deployment of spectrophotometric sensors on new platforms such as NOAAs Global Drifter Program, a network of non-recovered surface drifting buoys, which would greatly extend the spatial and temporal resolution of ocean acidification measurements.

  14. Spectrophotometric determination of trace and ultratrace levels of boron in silicon and chlorosilane samples

    International Nuclear Information System (INIS)

    Chen, J.S.; Lin, H.M.; Yang, M.H.

    1991-01-01

    Spectrophotometric methods for the determination of boron in the low μg/g and ng/g range in high-purity silicon and dichloro- and trichlorosilanes were investigated in detail. The procedures established involve dissolution of silicon samples and the hydrolyzed products of chlorosilane samples in hydrofluoric acid-containing reagents followed by evaporation of the silicon matrix as H 2 SiF 6 . The boron retained in the treated sample solution was then determined by a spectrophotometric method using carminic acid as a chromatic reagent. Special effort has been paid to the control of the analytical blank and reproducible determination of boron. The results indicate that addition of mannitol and proper control of the evaporation process are effective in preventing volatilization of boron during the evaporation of silicon matrix and can thus attain high recovery of boron and reproducible analysis. Through meticulous control of the analytical blank and experimental conditions, the limit of detection for boron determination with the established method can be as low as ng/g levels. Application of the methods to the determination of boron in various stages of purification of silicon and trichlorosilane as well as in borophosphosilicate film was conducted. (orig.)

  15. Determination of Nitrite and Nitrate in Natural Waters Using Flow Injection with Spectrophotometric Detection

    International Nuclear Information System (INIS)

    Yaqoob, M.; Nabi, A.

    2013-01-01

    A simple and sensitive flow injection spectrophotometric method is reported for the room temperature determination of nitrite and nitrate based on the Griess reaction and a copperised cadmium column for reduction of nitrate. Calibration graphs were linear over the range 2 - 1000 micro g N L /sup -1/ (R2 = 0.9997 and 0.9999, n = 9) with a limit of detection (3 s.d.) of 1.0 micro g N L and relative standard deviations (n = 10) of 0.9 and 1.2% for 50 micro g N L nitrite and nitrate respectively. The sample throughput was 50 h. The effect of reagent concentrations, physical parameters (flow rate, sample volume, reaction coil and copperised cadmium column length) and the potential interferences are reported. The effect of salinity on the blank and on the determination of nitrite and nitrate are also presented. The method was applied to natural waters (rainwater, freshwater and estuarine water) and the results for nitrite + nitrate (140 - 7310 micro g N L/sup -1/) were not significantly different (95% confidence interval) from results obtained using a segmented flow analyser reference method with spectrophotometric detection. (author)

  16. Spectrophotometric determination of nitrite by its catalytic effect on the oxidation of congo red with bromate

    Directory of Open Access Journals (Sweden)

    Zenovia Moldovan

    2012-08-01

    Full Text Available A novel simple, sensitive and rapid kinetic-spectrophotometric method for the determination of trace amounts of nitrite is proposed. The method is based on its catalytic effect on the oxidation of congo red (CR by potassium bromate in acidic solution. The oxidation reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of CR at a suitable λmax = 570 nm for the first 10–40 s from the start of the reaction. Under the optimum experimental conditions (sulfuric acid, 0.3 M; CR, 0.75Χ10-4 M; potassium bromate, 5Χ10-4 M and 25 oC, nitrite can be determined in the range of 0.015–0.75 µg mL−1 with the detection limit of 0.006 µg mL−1. The relative standard deviation of five replicate determination of 0.25 µg mL−1 nitrite was 2.5%. The proposed method was applied satisfactorily to the determination of nitrite in spiked drinking water samples.DOI: http://dx.doi.org/10.4314/bcse.v26i2.1

  17. Indirect spectrophotometric determination of arbutin, whitening agent through oxidation by periodate and complexation with ferric chloride

    Science.gov (United States)

    Barsoom, B. N.; Abdelsamad, A. M. E.; Adib, N. M.

    2006-07-01

    A simple and accurate spectrophotometric method for the determination of arbutin (glycosylated hydroquinone) is described. It is based on the oxidation of arbutin by periodate in presence of iodate. Excess periodate causes liberation of iodine at pH 8.0. The unreacted periodate is determined by measurement of the liberated iodine spectrophotometrically in the wavelength range (300-500 nm). A calibration curve was constructed for more accurate results and the correlation coefficient of linear regression analysis was -0.9778. The precision of this method was better than 6.17% R.S.D. ( n = 3). Regression analysis of Bear-Lambert plot shows good correlation in the concentration range 25-125 ug/ml. The identification limit was determined to be 25 ug/ml a detailed study of the reaction conditions was carried out, including effect of changing pH, time, temperature and volume of periodate. Analyzing pure and authentic samples containing arbutin tested the validity of the proposed method which has an average percent recovery of 100.86%. An alternative method is also proposed which involves a complexation reaction between arbutin and ferric chloride solution. The produced complex which is yellowish-green in color was determined spectophotometrically.

  18. Highly Selective and Sensitized Spectrophotometric Determination of Iron (3) Following Potentiometric Study

    International Nuclear Information System (INIS)

    Shokrollahi, A.; Ghaedi, M.; Rajabi, H.R.

    2007-01-01

    A simple, selective and sensitized spectrophotometric method for determination of trace amounts of Fe 3+ ion in tap and waste water solutions has been described. The spectrophotometric determination of Fe 3+ ion using Ferron in the presence of N,N-Dodecy trimethylammonium bromide (DTAB) has been carried out. The Beer's law is obeyed over the concentration range of 0.05-2.6 μg mL -1 of Fe 3+ ion with the relative standard deviation (RSD %) 3 L mol -1 cm -1 . Potentiometric pH titration has been used for prediction of protonation constants of ferron, and evaluating its stoichiometry and respective stability constant with Fe 3+ ion. As it is obvious the most likely species of ferron alone and its complexes are LH (log=7.64), LH 2 (logK=10.52), LH 3 (logK=11.74) and ML 2 (logβ= 23.68), ML 3 (logβ23.68), ML 3 H (logβ= 23.68), ML 3 H 2 (logβ= 23.68) and ML(OH) 2 (logβ=23.68) respectively

  19. Alanine dosimetry using a spectrophotometric ferric-xylenol orange complex readout

    International Nuclear Information System (INIS)

    Laere, K. van; Buysse, J.; Berkvens, P.

    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 2 SO 4 , 0.2 mM xylenol orange and 0.2 mM Fe 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 id , was introduced for this procedure as a measure of the indirect oxidation capacity of the radicals. It was found to be G id,0 (Fe 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)

  20. Liquid chromatographic and ultraviolet spectrophotometric determination of bevantolol and hydrochlorothiazide in feeds.

    Science.gov (United States)

    Spurlock, C H; Schneider, H G

    1984-01-01

    Separate assay methods have been developed for the 2 components of an 80 + 20 drug blend of bevantolol and hydrochlorothiazide (HCT) in admixtures with animal feed. Drug/diet admixtures are extracted with methanol for reverse phase ion-pair liquid chromatographic (LC) assay of bevantolol, and with acetonitrile for ultraviolet spectrophotometric assay of HCT. Bevantolol, a cardioselective beta blocker, is separated from soluble feed components with an RP-18 column, using methanol-water-acetic acid (60 + 40 + 1) containing 0. 005M octane-sulfonic acid, sodium salt, as ion-pairing reagent. HCT is determined spectrophotometrically in acetonitrile extracts, using a suitable blank extract as reference. Average recovery of HCT from an admixture of 0.5 mg blend/g diet is 94.5% +/- 4.3 RSD and at 2.0 mg/g, 101.5% +/- 3.5 RSD. Bevantolol recovery from the same admixtures is 101.8% +/- 2.7 RSD and 99.0% +/- 3.5 RSD, respectively, using the method as described.

  1. 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.

  2. Batch and flow-injection methods for the spectrophotometric determination of olanzapine

    Energy Technology Data Exchange (ETDEWEB)

    Jasinska, A.; Nalewajko, E

    2004-04-22

    An indirect batch spectrophotometric and direct flow-injection (FI) visible spectrophotometric methods have been developed for the determination of the novel anti-psychotic drug olanzapine (OLA). The batch method is based on the oxidation of olanzapine by a known excess of potassium hexacyanoferrate(III) in the presence of the mixture of sulphuric and phosphoric acids (1:1 (v/v)). The absorbance of unreacted oxidant is measured at 425 nm. The absorbance decreases linearly with increasing concentration of the assayed drug. The FI method with detection at 540 nm is based on the direct oxidation of olanzapine one of two oxidants, cerium(IV) sulphate or potassium hexacyanoferrate(III) in acidic medium. The calibration graph were linear over the range of 2.5-40 {mu}g ml{sup -1} in the batch method and 0.05-300 and 0.5-250 {mu}g ml{sup -1} in the FI methods, used cerium (IV) sulphate and potassium hexacyanoferrate (III) respectively. Both FI methods gave similar results in terms of precision and accuracy. The relative standard deviation (R.S.D.), was <1%. The accuracy, obtained from recovery experiments, was 97.9-99.4%. The batch method gave slightly higher R.S.D. values (up to 2.3%) and lower values of accuracy (the recovery was between 96.5 and 96.6%). The methods developed were applied to the determination of olanzapine in a pharmaceutical product.

  3. Spectrophotometric Quantification of Vilazodone Hydrochloride in Pharmaceutical Dosage Form Using Quality by Design Approach

    International Nuclear Information System (INIS)

    Panda, S.S.; Kumar, B.V.V.R.K.; Beg, S.; Behera, S.

    2015-01-01

    The present work deals with development and validation of a novel, robust, precise and accurate spectrophotometric method, for the estimation of vilazodone hydrochloride in tablets using the principle of Quality by Design (QbD). A fractional factorial design (FFD) was employed for initial parameter screening. Further the screened parameters were subjected to central composite design (CCD) for evaluating method robustness and method optimization. Different statistical parameters were evaluated to decide appropriateness of experimental data. Vilazodone shows absorption maximum at 285 nm using methanol. Factor screening slit width and sampling interval were identified as critical method variables, which were further evaluated by a CCD. Good linearity was obtained for vilazodone in the range of 5-60 μg/ mL with R"2 > 0.999. The method was found to be accurate with good average % recovery (more than 100 %). Developed method was validated as per ICH guidelines. Based on QbD development of spectrophotometric method ensured that quality is built into the method. The method was robust and can be applied for determination of the vilazodone in pharmaceutical dosage form. (author)

  4. Spectrophotometric Determination of Phenolic Antioxidants in the Presence of Thiols and Proteins

    Directory of Open Access Journals (Sweden)

    Aslı Neslihan Avan

    2016-08-01

    Full Text Available Development of easy, practical, and low-cost spectrophotometric methods is required for the selective determination of phenolic antioxidants in the presence of other similar substances. As electron transfer (ET-based total antioxidant capacity (TAC assays generally measure the reducing ability of antioxidant compounds, thiols and phenols cannot be differentiated since they are both responsive to the probe reagent. In this study, three of the most common TAC determination methods, namely cupric ion reducing antioxidant capacity (CUPRAC, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt/trolox equivalent antioxidant capacity (ABTS/TEAC, and ferric reducing antioxidant power (FRAP, were tested for the assay of phenolics in the presence of selected thiol and protein compounds. Although the FRAP method is almost non-responsive to thiol compounds individually, surprising overoxidations with large positive deviations from additivity were observed when using this method for (phenols + thiols mixtures. Among the tested TAC methods, CUPRAC gave the most additive results for all studied (phenol + thiol and (phenol + protein mixtures with minimal relative error. As ABTS/TEAC and FRAP methods gave small and large deviations, respectively, from additivity of absorbances arising from these components in mixtures, mercury(II compounds were added to stabilize the thiol components in the form of Hg(II-thiol complexes so as to enable selective spectrophotometric determination of phenolic components. This error compensation was most efficient for the FRAP method in testing (thiols + phenols mixtures.

  5. Spectrophotometric study on beryllium complex with Chromazurol S in the presence of zephiramine

    International Nuclear Information System (INIS)

    Nishida, Hiroshi

    1982-01-01

    Beryllium(II) reacted with Chromazurol S (CAS, H 4 L) to produce two types of 1:2 complexes in the presence of zephiramine, one of which was in a form of mononuclear Be(HL) 2 4 - showing an absorption maximum at 612 nm and other was in binuclear Be 2 (OH)(HL) 4 9 - showing an absorption maximum at 525 nm. The formation equilibrium of these complexes in the range of pH 5 to 10 was examined by the spectrophotometric method. The binuclear complex was found to be produced from the hydrolysis of the mononuclear complex through the following equation; Be(HL) 2 4 - + 1/2H 2 O reversible 1/2Be 2 (OH)(HL) 4 9 - + 1/2H + where zephiramine ion was not shown. The effect of anions such as chloride and sulfate ions on this equilibrium was observed. The apparent equilibrium constant decreased with the increase of the anion concentrations. The equilibrium constant was larger in the presence of sulfate ion than in chloride ion at the same concentration. In the practical spectrophotometric determination, however, these effects by such diverse ions could be successfully elimination by raising the pH to 10 so high as the above equilibrium was shifted rightward thoroughly. (author)

  6. Validation of a spectrophotometric methodology for the quantification of polysaccharides from roots of Operculina macrocarpa (jalapa

    Directory of Open Access Journals (Sweden)

    Marcos A.M. Galvão

    Full Text Available The roots from Operculina macrocarpa (L. Urb., Convolvulaceae, are widely used in Brazilian traditional medicine as a laxative and purgative. The biological properties of this drug material have been attributed to its polysaccharides content. Thus, the aim of this study was to evaluate the polysaccharide content in drug material from O. macrocarpa by spectrophotometric quantitative analysis. The root was used as plant material and the botanical identification was performed by macro and microscopic analysis. The plant material was used to validate the spectrophotometric procedures at 490 nm for the quantification of the reaction product from drug polysaccharides and phenol-sulfuric acid solution. The analytical procedure was evaluated in order to comply with the necessary legal requirements by the determination of the following parameters: specificity, linearity, selectivity, precision, accuracy and robustness. This study provides with a simple and valid analytical procedure (linear, precise, accurate and reproducible, which can be satisfactorily used for quality control and standardization of herbal drug from O. macrocarpa.

  7. An interval-valued reliability model with bounded failure rates

    DEFF Research Database (Denmark)

    Kozine, Igor; Krymsky, Victor

    2012-01-01

    The approach to deriving interval-valued reliability measures described in this paper is distinctive from other imprecise reliability models in that it overcomes the issue of having to impose an upper bound on time to failure. It rests on the presupposition that a constant interval-valued failure...... rate is known possibly along with other reliability measures, precise or imprecise. The Lagrange method is used to solve the constrained optimization problem to derive new reliability measures of interest. The obtained results call for an exponential-wise approximation of failure probability density...

  8. Reliability of clinical ICD-10 schizophrenia diagnoses

    DEFF Research Database (Denmark)

    Jakobsen, Klaus D; Frederiksen, Julie N; Hansen, Thomas

    2005-01-01

    Concern has been expressed as to the reliability of clinical ICD-10 diagnosis of schizophrenia. This study was designed to assess the diagnostic reliability of the clinical ICD-10 diagnosis of schizophrenia in a random sample of Danish in- and outpatients with a history of psychosis. A sample...... value (87%) of ICD-10 schizophrenia and an overall good agreement between clinical and OPCRIT-derived diagnoses (kappa=0.60). An even higher positive predictive value was obtained when diagnoses were amalgamated into a diagnostic entity of schizophrenia-spectrum disorders (98%). Near perfect agreement...... was seen between OPCRIT-derived ICD-10 and DSM-IV diagnoses (kappa=0.87). Thus, this study demonstrates high reliability of the clinical diagnosis of schizophrenia and even more so of the diagnosis of schizophrenia-spectrum disorder....

  9. Reliability of construction materials

    International Nuclear Information System (INIS)

    Merz, H.

    1976-01-01

    One can also speak of reliability with respect to materials. While for reliability of components the MTBF (mean time between failures) is regarded as the main criterium, this is replaced with regard to materials by possible failure mechanisms like physical/chemical reaction mechanisms, disturbances of physical or chemical equilibrium, or other interactions or changes of system. The main tasks of the reliability analysis of materials therefore is the prediction of the various failure reasons, the identification of interactions, and the development of nondestructive testing methods. (RW) [de

  10. Structural Reliability Methods

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Madsen, H. O.

    The structural reliability methods quantitatively treat the uncertainty of predicting the behaviour and properties of a structure given the uncertain properties of its geometry, materials, and the actions it is supposed to withstand. This book addresses the probabilistic methods for evaluation...... of structural reliability, including the theoretical basis for these methods. Partial safety factor codes under current practice are briefly introduced and discussed. A probabilistic code format for obtaining a formal reliability evaluation system that catches the most essential features of the nature...... of the uncertainties and their interplay is the developed, step-by-step. The concepts presented are illustrated by numerous examples throughout the text....

  11. Reliability and mechanical design

    International Nuclear Information System (INIS)

    Lemaire, Maurice

    1997-01-01

    A lot of results in mechanical design are obtained from a modelisation of physical reality and from a numerical solution which would lead to the evaluation of needs and resources. The goal of the reliability analysis is to evaluate the confidence which it is possible to grant to the chosen design through the calculation of a probability of failure linked to the retained scenario. Two types of analysis are proposed: the sensitivity analysis and the reliability analysis. Approximate methods are applicable to problems related to reliability, availability, maintainability and safety (RAMS)

  12. RTE - 2013 Reliability Report

    International Nuclear Information System (INIS)

    Denis, Anne-Marie

    2014-01-01

    RTE publishes a yearly reliability report based on a standard model to facilitate comparisons and highlight long-term trends. The 2013 report is not only stating the facts of the Significant System Events (ESS), but it moreover underlines the main elements dealing with the reliability of the electrical power system. It highlights the various elements which contribute to present and future reliability and provides an overview of the interaction between the various stakeholders of the Electrical Power System on the scale of the European Interconnected Network. (author)

  13. Assessing reliability in energy supply systems

    International Nuclear Information System (INIS)

    McCarthy, Ryan W.; Ogden, Joan M.; Sperling, Daniel

    2007-01-01

    Reliability has always been a concern in the energy sector, but concerns are escalating as energy demand increases and the political stability of many energy supply regions becomes more questionable. But how does one define and measure reliability? We introduce a method to assess reliability in energy supply systems in terms of adequacy and security. It derives from reliability assessment frameworks developed for the electricity sector, which are extended to include qualitative considerations and to be applicable to new energy systems by incorporating decision-making processes based on expert opinion and multi-attribute utility theory. The method presented here is flexible and can be applied to any energy system. To illustrate its use, we apply the method to two hydrogen pathways: (1) centralized steam reforming of imported liquefied natural gas with pipeline distribution of hydrogen, and (2) on-site electrolysis of water using renewable electricity produced independently from the electricity grid

  14. 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

  15. Approach to reliability assessment

    International Nuclear Information System (INIS)

    Green, A.E.; Bourne, A.J.

    1975-01-01

    Experience has shown that reliability assessments can play an important role in the early design and subsequent operation of technological systems where reliability is at a premium. The approaches to and techniques for such assessments, which have been outlined in the paper, have been successfully applied in variety of applications ranging from individual equipments to large and complex systems. The general approach involves the logical and systematic establishment of the purpose, performance requirements and reliability criteria of systems. This is followed by an appraisal of likely system achievment based on the understanding of different types of variational behavior. A fundamental reliability model emerges from the correlation between the appropriate Q and H functions for performance requirement and achievement. This model may cover the complete spectrum of performance behavior in all the system dimensions

  16. The rating reliability calculator

    Directory of Open Access Journals (Sweden)

    Solomon David J

    2004-04-01

    Full Text Available Abstract Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program.

  17. Structural systems reliability analysis

    International Nuclear Information System (INIS)

    Frangopol, D.

    1975-01-01

    For an exact evaluation of the reliability of a structure it appears necessary to determine the distribution densities of the loads and resistances and to calculate the correlation coefficients between loads and between resistances. These statistical characteristics can be obtained only on the basis of a long activity period. In case that such studies are missing the statistical properties formulated here give upper and lower bounds of the reliability. (orig./HP) [de

  18. Reliability and maintainability

    International Nuclear Information System (INIS)

    1994-01-01

    Several communications in this conference are concerned with nuclear plant reliability and maintainability; their titles are: maintenance optimization of stand-by Diesels of 900 MW nuclear power plants; CLAIRE: an event-based simulation tool for software testing; reliability as one important issue within the periodic safety review of nuclear power plants; design of nuclear building ventilation by the means of functional analysis; operation characteristic analysis for a power industry plant park, as a function of influence parameters

  19. Reliability data book

    International Nuclear Information System (INIS)

    Bento, J.P.; Boerje, S.; Ericsson, G.; Hasler, A.; Lyden, C.O.; Wallin, L.; Poern, K.; Aakerlund, O.

    1985-01-01

    The main objective for the report is to improve failure data for reliability calculations as parts of safety analyses for Swedish nuclear power plants. The work is based primarily on evaluations of failure reports as well as information provided by the operation and maintenance staff of each plant. In the report are presented charts of reliability data for: pumps, valves, control rods/rod drives, electrical components, and instruments. (L.E.)

  20. Multidisciplinary System Reliability Analysis

    Science.gov (United States)

    Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)

    2001-01-01

    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code, developed under the leadership of NASA Glenn Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multidisciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  1. Analysis and Application of Reliability

    International Nuclear Information System (INIS)

    Jeong, Hae Seong; Park, Dong Ho; Kim, Jae Ju

    1999-05-01

    This book tells of analysis and application of reliability, which includes definition, importance and historical background of reliability, function of reliability and failure rate, life distribution and assumption of reliability, reliability of unrepaired system, reliability of repairable system, sampling test of reliability, failure analysis like failure analysis by FEMA and FTA, and cases, accelerated life testing such as basic conception, acceleration and acceleration factor, and analysis of accelerated life testing data, maintenance policy about alternation and inspection.

  2. Dose intercomparison for 400–500 keV electrons using FWT-60 film and glutamine (spectrophotometric readout) dosimeters

    DEFF Research Database (Denmark)

    Gupta, B. L.; Nilekani, S. R.; Gehringer, P.

    1986-01-01

    This paper describes the dose and the depth dose measurements with FWT-60 film and glutamine (Spectrophotometric readout) dosimeters for 400–500 keV electrons. The glutamine powder was spread uniformly in polyethylene bags and the powder thickness in each bag was 5 mg cm−2. Both techniques show...

  3. The rapid spectrophotometric determination of vanadium in tool steel with 9(6-methyl-2-pyridyl)azo5

    International Nuclear Information System (INIS)

    Beaupre, P.W.; Holland, W.J.

    1980-01-01

    An extractive-spectrophotometric method for the determination of vanadium in tool steel is described. The only sample pretreatment required is dissolution. An average vanadium of 2.06% was obtained on a standard sample compared to the recommended value of 2.06%. (author)

  4. Spectrophotometric studies on complex formation of 5-nitro-3-sulpho-salicylic acid with niobium(V)

    International Nuclear Information System (INIS)

    Parmar, D.S.; Shivahare, G.C.

    1975-01-01

    5-nitro-3-sulpho-salicylic acid forms a yellow complex witn niobium(V) at pH 9.9 and the reaction has been successfully studied spectrophotometrically. The results of the Job's continuous variation method and the mole ratio method indicate a composition of 1:2 for the complex. Stability constant of the complex has also been determined. (author)

  5. Contributions te the study of methods and factors affecting the spectrophotometric determination of boron traces with carmin uranium compounds

    International Nuclear Information System (INIS)

    Fernandez Cellini, R.; Gasco Sanchez, L.

    1956-01-01

    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

  6. Spectrophotometric study of the complexation reaction between niobium(V) and 5-sulpho-3-nitro-salicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Parmar, D S; Shivahare, G C [Rajasthan Univ., Jaipur (India). Dept. of Chemistry

    1975-04-01

    5-sulpho-3 nitro-salicylic acid forms a yellow complex with niobium(V) at pH 8.5 and the reaction has been successfully studied spectrophotometrically. The results of the Job's continuous variation method and the molar ratio method indicate a composition of 1:2 for the complex. Stability constant of the complex has also been determined. (auth)

  7. Spectrophotometric studies on complex formation of 5-nitro-3-sulpho-salicylic acid with niobium(V)

    Energy Technology Data Exchange (ETDEWEB)

    Parmar, D S; Shivahare, G C [Rajasthan Univ., Jaipur (India). Dept. of Chemistry

    1975-11-01

    5-nitro-3-sulpho-salicylic acid forms a yellow complex witn niobium(V) at pH 9.9 and the reaction has been successfully studied spectrophotometrically. The results of the Job's continuous variation method and the mole ratio method indicate a composition of 1:2 for the complex. Stability constant of the complex has also been determined.

  8. Quantitative HPLC Analysis of Rosmarinic Acid in Extracts of "Melissa officinalis" and Spectrophotometric Measurement of Their Antioxidant Activities

    Science.gov (United States)

    Canelas, Vera; da Costa, Cristina Teixeira

    2007-01-01

    The students prepare tea samples using different quantities of lemon balm leaves ("Melissa officinalis") and measure the rosmarinic acid contents by an HPLC-DAD method. The antioxidant properties of the tea samples are evaluated by a spectrophotometric method using a radical-scavenging assay with DPPH. (2,2-diphenyl-1-picrylhydrazyl). Finally the…

  9. A COMPARISON OF A SPECTROPHOTOMETRIC (QUERCETIN) METHOD AND AN ATOMIC-ABSORPTION METHOD FOR DETERMINATION OF TIN IN FOOD

    DEFF Research Database (Denmark)

    Engberg, Å

    1973-01-01

    Procedures for the determination of tin in food, which involve a spectrophotometric method (with the quercetin-tin complex) and an atomic-absorption method, are described. The precision of the complete methods and of the individual analytical steps required is evaluated, and the parameters...

  10. Global Derivatives

    DEFF Research Database (Denmark)

    Andersen, Torben Juul

    approaches to dealing in the global business environment." - Sharon Brown-Hruska, Commissioner, Commodity Futures Trading Commission, USA. "This comprehensive survey of modern risk management using derivative securities is a fine demonstration of the practical relevance of modern derivatives theory to risk......" provides comprehensive coverage of different types of derivatives, including exchange traded contracts and over-the-counter instruments as well as real options. There is an equal emphasis on the practical application of derivatives and their actual uses in business transactions and corporate risk...... management situations. Its key features include: derivatives are introduced in a global market perspective; describes major derivative pricing models for practical use, extending these principles to valuation of real options; practical applications of derivative instruments are richly illustrated...

  11. SPECTROPHOTOMETRIC DETERMINATION OF ACETYLCYSTEINE IN PHARMACEUTICAL FORMULATIONS USING 2,3-DICHLORO-1,4-NAPTHOQUINONE

    Directory of Open Access Journals (Sweden)

    A. O. Donchenko

    2015-04-01

    Full Text Available The aim of research was the development and validation ofspectrophotometric method foracetylcysteine assay in pharmaceutical formulations.Тhe proposed method is based on the reaction with 2,3-dichloro-1,4-naphthoquinone and the formation of colored products that exhibit absorption maxima at 425 nm. Introduction Many analytical methods have been published for acetylcysteine assay in pharmaceutical formulations as high-performance liquid chromatography (HPLC, fluorimetry and chemiluminescence. Some of these methods are time consuming or require expensive equipment. Other published methods suffer from lack of selectivity and sensitivity. Spectrophotometry is the most widely used technique in pharmaceutical analysis because it is simple, economic, and easily available to most quality control laboratories. In the present work, we propose a simple and accurate spectrophotometric method for acetylcysteine assay in pharmaceutical formulations. Materials and Methods Reagents: Reference standard acetylcysteinesubstance; 2,3-dichloro-1,4-naphthoquinone. All chemicals and solvents were of analytical grade. DMFA was used as a solvent. Pharmaceutical preparations:powder for oral solution «ACC 200» 200 mgseries number50026151 (Salutas Pharma CmbH, Germany; effervescent tablets «Fluimucil» 600 mg (Zambon S.P.A., Italy and «ACC LONG» 600 mg (Salutas Pharma CmbH, Germany series numbers 321284 and DH2740; solution for injections «Fluimucil» 100 mg/ml (Zambon S.P.A., Italyseries number28002492. Solutions: Acetylcysteine stock solution (0,16%; DMFAsolution of 2,3-dichloro-1,4-naphthoquinone (4%. Equipment Analytical balance (ABT-120-5DM; UV-VIS spectrophotometer (Specord 200; water bath (MemmertWNB 7-45;quartz cells. Results Acetylcysteine was determined using a spectrophotometric method based on the reaction with 2,3-dichloro-1,4-naphthoquinone to form yellow colored reaction products with absorption maxima at 425 nm. The effect of reaction time and

  12. Analyzing the Reliability of the easyCBM Reading Comprehension Measures: Grade 2. Technical Report #1201

    Science.gov (United States)

    Lai, Cheng-Fei; Irvin, P. Shawn; Alonzo, Julie; Park, Bitnara Jasmine; Tindal, Gerald

    2012-01-01

    In this technical report, we present the results of a reliability study of the second-grade multiple choice reading comprehension measures available on the easyCBM learning system conducted in the spring of 2011. Analyses include split-half reliability, alternate form reliability, person and item reliability as derived from Rasch analysis,…

  13. Analyzing the Reliability of the easyCBM Reading Comprehension Measures: Grade 3. Technical Report #1202

    Science.gov (United States)

    Lai, Cheng-Fei; Irvin, P. Shawn; Park, Bitnara Jasmine; Alonzo, Julie; Tindal, Gerald

    2012-01-01

    In this technical report, we present the results of a reliability study of the third-grade multiple choice reading comprehension measures available on the easyCBM learning system conducted in the spring of 2011. Analyses include split-half reliability, alternate form reliability, person and item reliability as derived from Rasch analysis,…

  14. Analyzing the Reliability of the easyCBM Reading Comprehension Measures: Grade 5. Technical Report #1204

    Science.gov (United States)

    Park, Bitnara Jasmine; Irvin, P. Shawn; Lai, Cheng-Fei; Alonzo, Julie; Tindal, Gerald

    2012-01-01

    In this technical report, we present the results of a reliability study of the fifth-grade multiple choice reading comprehension measures available on the easyCBM learning system conducted in the spring of 2011. Analyses include split-half reliability, alternate form reliability, person and item reliability as derived from Rasch analysis,…

  15. Analyzing the Reliability of the easyCBM Reading Comprehension Measures: Grade 4. Technical Report #1203

    Science.gov (United States)

    Park, Bitnara Jasmine; Irvin, P. Shawn; Alonzo, Julie; Lai, Cheng-Fei; Tindal, Gerald

    2012-01-01

    In this technical report, we present the results of a reliability study of the fourth-grade multiple choice reading comprehension measures available on the easyCBM learning system conducted in the spring of 2011. Analyses include split-half reliability, alternate form reliability, person and item reliability as derived from Rasch analysis,…

  16. Analyzing the Reliability of the easyCBM Reading Comprehension Measures: Grade 6. Technical Report #1205

    Science.gov (United States)

    Irvin, P. Shawn; Alonzo, Julie; Park, Bitnara Jasmine; Lai, Cheng-Fei; Tindal, Gerald

    2012-01-01

    In this technical report, we present the results of a reliability study of the sixth-grade multiple choice reading comprehension measures available on the easyCBM learning system conducted in the spring of 2011. Analyses include split-half reliability, alternate form reliability, person and item reliability as derived from Rasch analysis,…

  17. Analyzing the Reliability of the easyCBM Reading Comprehension Measures: Grade 7. Technical Report #1206

    Science.gov (United States)

    Irvin, P. Shawn; Alonzo, Julie; Lai, Cheng-Fei; Park, Bitnara Jasmine; Tindal, Gerald

    2012-01-01

    In this technical report, we present the results of a reliability study of the seventh-grade multiple choice reading comprehension measures available on the easyCBM learning system conducted in the spring of 2011. Analyses include split-half reliability, alternate form reliability, person and item reliability as derived from Rasch analysis,…

  18. Multi-wavelength spectrophotometric analysis for detection of xanthochromia in cerebrospinal fluid and accuracy for the diagnosis of subarachnoid hemorrhage.

    Science.gov (United States)

    Smith, Andrew; Wu, Alan H B; Lynch, Kara L; Ko, Nerissa; Grenache, David G

    2013-09-23

    Cerebrospinal fluid (CSF) was examined for bilirubin, an important indicator for diagnosis of subarachnoid hemorrhage (SAH). A multi-wavelength (340, 415, and 460 nm) spectrophotometric assay was developed for the quantitative measurement of bilirubin in CSF, enabling the mathematical correction for absorbance of hemoglobin and proteins. Bilirubin and hemoglobin results were correlated to HPLC and a standard colorimetric assay, respectively. A subset of samples was sent for an absorbance reading at 450 nm following baseline correction. The multi-wavelength bilirubin assay was validated on 70 patients with confirmed SAH and 70 patients with neurologic symptoms who ruled out for SAH. The multi-wavelength spectrophometric assay demonstrated no interferences due to proteins (albumin) up to 30 g/l or oxyhemoglobin up to 260 mg/l. The assay limit of detection was 0.2 mg/l, linear to 20 mg/l, and CVs ranged from 1 to 6% at bilirubin concentrations of 0.84 and 2.1mg/l. The spectrophotometric assay correlated to HPLC and the colorimetric assay for bilirubin and hemoglobin, respectively. Results also correlated to the absorbance method (with removal of samples with high hemoglobin and proteins). The area under the ROC curve for diagnosis of SAH was 0.971 and 0.954 for the HPLC and spectrophotometric assay, respectively. At a cutoff of 0.2mg/l, the clinical specificity was 100% for both assays, and the clinical sensitivity was 94.3% and 88.6% for SAH for the HPLC and spectrophotometric asays, respectively. The multi-wavelength spectrophotometric assay is an objective alternative to visual inspection, HPLC, and absorbance for CSF bilirubin. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Proposed reliability cost model

    Science.gov (United States)

    Delionback, L. M.

    1973-01-01

    The research investigations which were involved in the study include: cost analysis/allocation, reliability and product assurance, forecasting methodology, systems analysis, and model-building. This is a classic example of an interdisciplinary problem, since the model-building requirements include the need for understanding and communication between technical disciplines on one hand, and the financial/accounting skill categories on the other. The systems approach is utilized within this context to establish a clearer and more objective relationship between reliability assurance and the subcategories (or subelements) that provide, or reenforce, the reliability assurance for a system. Subcategories are further subdivided as illustrated by a tree diagram. The reliability assurance elements can be seen to be potential alternative strategies, or approaches, depending on the specific goals/objectives of the trade studies. The scope was limited to the establishment of a proposed reliability cost-model format. The model format/approach is dependent upon the use of a series of subsystem-oriented CER's and sometimes possible CTR's, in devising a suitable cost-effective policy.

  20. Reliability and Inequality Measures for the Weimal Distribution ...

    African Journals Online (AJOL)

    ). This article aimed at discussing both reliability and inequality measures from the Weimal distribution. The work has derived and discussed theoretically, expressions for the survival and hazard function of the Weimal distribution. The ordinary ...

  1. Requirements of safety and reliability

    International Nuclear Information System (INIS)

    Franzen, L.F.

    1977-01-01

    The safety strategy for nuclear power plants is characterized by the fact that the high level of safety was attained not as a result of experience, but on the basis of preventive accident analyses and the findings derived from such analyses. Although, in these accident analyses, the deterministic approach is predominant it is supplemented by reliability analyses. The accidents analyzed in nuclear licensing procedures cover a wide spectrum from minor incidents to the design basis accidents which determine the design of the safety devices. The initial and boundary conditions, which are essential for accident analyses, and the determination of the loads occuring in various states during regular operation and in accidents flow into the design of the individual systems and components. The inevitable residual risk and its origins are discussed. (orig./HP) [de

  2. Reliability Centered Maintenance - Methodologies

    Science.gov (United States)

    Kammerer, Catherine C.

    2009-01-01

    Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies.

  3. Issues in cognitive reliability

    International Nuclear Information System (INIS)

    Woods, D.D.; Hitchler, M.J.; Rumancik, J.A.

    1984-01-01

    This chapter examines some problems in current methods to assess reactor operator reliability at cognitive tasks and discusses new approaches to solve these problems. The two types of human failures are errors in the execution of an intention and errors in the formation/selection of an intention. Topics considered include the types of description, error correction, cognitive performance and response time, the speed-accuracy tradeoff function, function based task analysis, and cognitive task analysis. One problem of human reliability analysis (HRA) techniques in general is the question of what are the units of behavior whose reliability are to be determined. A second problem for HRA is that people often detect and correct their errors. The use of function based analysis, which maps the problem space for plant control, is recommended

  4. Spectrophotometric analysis of flavonoid-DNA binding interactions at physiological conditions

    Science.gov (United States)

    Janjua, Naveed Kausar; Siddiqa, Asima; Yaqub, Azra; Sabahat, Sana; Qureshi, Rumana; Haque, Sayed ul

    2009-12-01

    Mode of interactions of three flavonoids [morin (M), quercetin (Q), and rutin (R)] with chicken blood ds.DNA (ck.DNA) has been investigated spectrophotometrically at different temperatures including body temperature (310 K) and at two physiological pH values, i.e. 7.4 (human blood pH) and 4.7 (stomach pH). The binding constants, Kf, evaluated using Benesi-Hildebrand equation showed that the flavonoids bind effectively through intercalation at both pH values and body temperature. Quercetin, somehow, showed greater binding capabilities with DNA. The free energies of flavonoid-DNA complexes indicated the spontaneity of their binding. The order of binding constants of three flavonoids at both pH values were found to be Kf(Q) > Kf(R) > Kf(M) and at 310 K.

  5. The development of a new inhibition kinetic spectrophotometric method for determination of phenylhydrazine

    Directory of Open Access Journals (Sweden)

    VIOLETA D. MITIC

    2005-07-01

    Full Text Available Anew sensitive kinetic method has been developed for the determination of trace amounts of phenylhydrazine in the range of 1.08×10-7 to 1.08×10-6 g/cm3. The detection limit of this method is 0.008 mg/cm3, based on the 3Sb criterion. Themethod is based on the inhibitory effect of phenylhydrazine on the oxidation of Victoria Blue 4-R by KBrO3. The reaction was monitored spectrophotometrically at 596.3 nm. The method development includes the optimization of the reagent concentration and temperature. The kinetic parameters of the reaction are reported and a rate equation is suggested. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The new developedmethod was found to have fairly good selectivity, sensitivity, simplicity and rapidity.

  6. Spectrophotometric Determination of Doxycycline Hyclate in Pure and Capsule using Diazotization Reaction

    Directory of Open Access Journals (Sweden)

    Ruba Fahmi Abbas

    2017-07-01

    Full Text Available A sensitive spectrophotometric method has been developed for the determination of Doxycycline hyclate (DCH as pure and  capsule forms. This method is based on diazotization of primary amine group of benzocaine with sodium nitrite in hydrochloric acid medium; the formed diazonium salt is then reacted with DCH in sodium hydroxide medium, to form yellow – orange Azo dye. Beer's law is obeyed in the concentration rang 16-34mg. ml-1 at 480 nm with detection limit LOD and molar absorptivity Є were found to be 0.418 mg.ml-1 and 2.214× 10+4 L.mol-1.cm-1, respectively.

  7. Spectrophotometric procedure using rhodamine B for determination of submicrogram quantities of antimony in rocks

    Science.gov (United States)

    Schnepfe, M.M.

    1973-01-01

    A spectrophotometric procedure using Rhodamine B is given for the determination of antimony in mineralized rocks after its separation as stibine. A study of the Rhodamine B reaction points to the importance of the order of addition of reagents in enhancing sensitivity and increasing the stability of the system. The tolerance of some 26 elements is established for the overall procedure. Although the limit of determination is approximately 0??5 ppm Sb in a 0??2-g sample, the procedure is intended primarily for screening samples containing more than 1 ppm Sb. In pure solutions 0??1 ??g of antimony can be determined with a relative standard deviation of 25%. For >0??2 ??g of antimony a relative standard deviation of 15% or less can be expected. ?? 1973.

  8. IMPROVED SPECTROPHOTOMETRIC CALIBRATION OF THE SDSS-III BOSS QUASAR SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Margala, Daniel; Kirkby, David [Frederick Reines Hall, Department of Physics and Astronomy, University of California, Irvine, CA (United States); Dawson, Kyle [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Bailey, Stephen [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Blanton, Michael [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Schneider, Donald P., E-mail: dmargala@uci.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2016-11-10

    We present a model for spectrophotometric calibration errors in observations of quasars from the third generation of the Sloan Digital Sky Survey 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, including the measurement of baryon acoustic oscillations using the Ly α forest. Our model suggests that, on average, the observed quasar flux in BOSS is overestimated by ∼19% at 3600 Å and underestimated by ∼24% at 10,000 Å. Our corrections for the entire BOSS quasar sample are publicly available.

  9. TOWARD A NETWORK OF FAINT DA WHITE DWARFS AS HIGH-PRECISION SPECTROPHOTOMETRIC STANDARDS

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, G.; Matheson, T.; Saha, A.; Claver, J. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Axelrod, T.; Olszewski, E. [University of Arizona, Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Holberg, J. B. [University of Arizona, Lunar and Planetary Laboratory, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Stubbs, C. W. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Bohlin, R. C.; Deustua, S.; Rest, A., E-mail: gnarayan@noao.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2016-05-10

    We present the initial results from a program aimed at establishing a network of hot DA white dwarfs to serve as spectrophotometric standards for present and future wide-field surveys. These stars span the equatorial zone and are faint enough to be conveniently observed throughout the year with large-aperture telescopes. The spectra of these white dwarfs are analyzed in order to generate a non-local-thermodynamic-equilibrium model atmosphere normalized to Hubble Space Telescope colors, including adjustments for wavelength-dependent interstellar extinction. Once established, this standard star network will serve ground-based observatories in both hemispheres as well as space-based instrumentation from the UV to the near IR. We demonstrate the effectiveness of this concept and show how two different approaches to the problem using somewhat different assumptions produce equivalent results. We discuss the lessons learned and the resulting corrective actions applied to our program.

  10. Optical spectrophotometric atlas of Supernova 1987A in the LMC. I. The first 130 days

    International Nuclear Information System (INIS)

    Phillips, M.M.; Heathcote, S.R.; Hamuy, M.; Navarrete, M.

    1988-01-01

    Optical spectrophotometry of SN 1987A in the Large Magellanic Cloud (LMC) covering the first 5 months since outburst is presented. More than 80 spectra were obtained at Cerro Tololo over this period, mostly with the 2D-Frutti two-dimensional photon-counting detector on the 1-m telescope. The spectrophotometric calibration of the 2D-Frutti data is considered in detail. Through a comparison with broadband photometry, it is shown that the accuracy of the 2D-Frutti spectrophotometry is + or - 5 percent in absolute terms, and that the relative calibration for any single spectrum is accurate to + or - 3 percent. CCD spectrophotometry obtained on the first night of observation (Feb. 25, 1987) is also briefly discussed. Radial velocities for several prominent absorption and emission features are measured from these combined data. 13 references

  11. Determination of phenol in locally grown fruits and vegetable by spectrophotometric method

    International Nuclear Information System (INIS)

    Iqbal, M.; Khan, F.A.; Farooqui, Z.H.; Ifrahim, A.F.K.

    2005-01-01

    Spectrophotometric method for the determination of phenol in the sample of locally grown fruits apple, pear, sweet orange and vegetable radish of Quetta, Hyderabad and Nawabshah are described juices from these fruits and vegetable were squeezed, filtered and decolorized with charcoal. The antipyrine dye formed by reaction between phenol and 4-aminoantipyrine was analyzed. The calibration graphs were prepared in the range of 0.5 to 4 ppm of phenol. Phenol in apple, pear and sweet orange was found to be in the range of 1-1.2 ppm and in radish was found to be 0.5 ppm. Possible source of organic pollutant were pointed out and were discussed. Limits of detection of the method was investigated and was found to be 0.2 mu g/ml

  12. Spectrophotometric determination of cyclamate in soft drinks and desserts: complementary collaborative study.

    Science.gov (United States)

    Sjöberg, A M

    1988-01-01

    Fifteen official food control laboratories participated in a collaborative study of a spectrophotometric method to determine cyclamate in a soft drink and a dessert at concentrations of 90-311 mg/L and 202-526 mg/kg, respectively, with blind duplicates and a blank. Average recovery from the soft drink was 97.5%, and from the dessert, 98.6%. Reproducibility relative standard deviations were 4.7-6.5% and 6.9-8.5%, respectively. The outlier percentage was 5.5%. This study complements an earlier work by leading Nordic food laboratories and was designed according to the latest recommendations. The results of this study were compared with those of the earlier collaborative study and with general collaborative results obtained by AOAC.

  13. Validated UV-spectrophotometric method for the evaluation of the efficacy of makeup remover.

    Science.gov (United States)

    Charoennit, P; Lourith, N

    2012-04-01

    A UV-spectrophotometric method for the analysis of makeup remover was developed and validated according to ICH guidelines. Three makeup removers for which the main ingredients consisted of vegetable oil (A), mineral oil and silicone (B) and mineral oil and water (C) were sampled in this study. Ethanol was the optimal solvent because it did not interfere with the maximum absorbance of the liquid foundation at 250 nm. The linearity was determined over a range of makeup concentrations from 0.540 to 1.412 mg mL⁻¹ (R² = 0.9977). The accuracy of this method was determined by analysing low, intermediate and high concentrations of the liquid foundation and gave 78.59-91.57% recoveries with a relative standard deviation of makeup remover efficacy. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  14. Thorium coprecipitation method for spectrophotometric determination of arsenic (III) and arsenic (V) in groundwaters

    International Nuclear Information System (INIS)

    Tamari, Yuzo; Yamamoto, Nobuki; Tsuji, Haruo; Kusaka, Yuzuru

    1989-01-01

    A new coprecipitation method for the spectrophotometry of arsenic (III) and arsenic (V) in groundwater has been developed. Arsenic (III) and arsenic (V) were coprecipitated with thorium (IV) hydroxide from 1000ml of groundwater at pH9. The precipitate was centrifuged and then dissolved with hydrochloric acid. Arsenic (III) was spectrophotometrically determined by the usual silver diethylditiocarbamate (Ag-DDTC) method after generating the arsenic to arsine with sodium tetrahydroborate under masking the thorium with EDTA-NaF at pH6. From another portion of the same groundwater, both arsenic (III) and arsenic (V) were determined by the Ag-DDTC method after reducing all the arsenic to arsine with sodium tetrahydroborate at pH less than 1 in the presence of the EDTA-NaF. The concentration of arsenic (V) was obtained by subtracting that of arsenic (III) from the total for arsenic. (author)

  15. Investigation of a New Spectrophotometric Method for the analysis of carbohydrates using glucose as model

    International Nuclear Information System (INIS)

    Hussain, Z.; Ali, A.; Shah, N.U.; Khan, K.M.

    2013-01-01

    Carbohydrates are biomolecule of significant importance. Its analysis is of prime importance in the clinical investigations, delivery of medicines and quality control operations of food and fuel products. Based on its importance a novel spectrophotometric method was investigated for the trace analysis of carbohydrates using glucose as model carbohydrate. This method is based on glucosazation followed by oxidation of the glucosazone with acidified iron (III) chloride. Oxidation of the glucsazone is necessary for enhancing the color intensity and optimum conditions were investigated for the process. All the absorbance measurements were carried out using 390 nm as gamma max. The ratio of the reactants was 1: 1.5: 0.1 mole for the glucose, phenyl hydrazine and iron (III) chloride. This method was used for the analysis of carbohydrates in real samples from plants, industrial products, blood and urine using glucose as reference. (author)

  16. A spectrophotometric method for the determination of Hydrogen Sulphide sugar cane juice and water

    International Nuclear Information System (INIS)

    Mahadeviah, S.; Galil, Mansour S.; Kumar, M.S. Yogender; Suresha, M.S.; Nagendrappa, G.

    2006-01-01

    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)

  17. The effect of non-aqueous solvents on spectrophotometric analysis of lead (II)

    International Nuclear Information System (INIS)

    Ramadan, A.A.; Bahbouh, M.; Kamuah, M.

    1992-01-01

    The effect of the following non-aqueous solvents: Methanol, Ethanol, Propanol, iso-propanol, dimethylsulfoxide, dimethylformamide and acetonitrile on spectrophotometric analysis of lead (II) was studied. One absorption peak at range 220-340 nm was observed. The values of maximum wave length (λ max ) and maximum molar absorptivity coefficient (ε max ) vary in accordance with the above solvents and the concentration of HC1. the analytical curves, A=f(C Pb 2+ ), for the determination of lead (II) in presence 5 M HC1 (in methanol) and 7 M HC1 (in other solvents) showed linear proportionality over the concentration range 2.5x10 -5 - 2.0x10 -4 M Pb 2+ . (author). 16 Refs., 4 figs., 2 Tabs

  18. Spectrophotometric flow injection catalytic determination of molybdenum in plant digest using ion exchange resin

    International Nuclear Information System (INIS)

    Pessenda, L.C.R.

    1987-03-01

    A spectrophotometric flow injection analytical method based on the catalytic action of molybdenum on the oxidation of iodide by hydrogen peroxide in acidic medium is proposed for the molybdenum determination in plant digests. A cation exchange resin column is incorporated into a flow injection system for removal of interferents. The following system variables were investigated and optimized: reagent concentrations, sample injection volume, mixing and reaction coil lengths, temperature, sampling time, pumping rate and concentration of eluting agents. The effects of interfering species and of the acidity of samples on the molybdenum retention by the ion exchange resin column were investigated. The proposed method is characterized by good precision (r.s.d. (2.0%), a sampling rate of about 40 samples per hour, and permits the determination of molybdenum in plant digests in the range 1.0 to 40.0 μg/l. The results compare well with those obtained by graphite furnace atomic absorption spectrometry. (author) [pt

  19. Distributed Fast Self-Organized Maps for Massive Spectrophotometric Data Analysis †

    Directory of Open Access Journals (Sweden)

    Carlos Dafonte

    2018-05-01

    Full Text Available Analyzing huge amounts of data becomes essential in the era of Big Data, where databases are populated with hundreds of Gigabytes that must be processed to extract knowledge. Hence, classical algorithms must be adapted towards distributed computing methodologies that leverage the underlying computational power of these platforms. Here, a parallel, scalable, and optimized design for self-organized maps (SOM is proposed in order to analyze massive data gathered by the spectrophotometric sensor of the European Space Agency (ESA Gaia spacecraft, although it could be extrapolated to other domains. The performance comparison between the sequential implementation and the distributed ones based on Apache Hadoop and Apache Spark is an important part of the work, as well as the detailed analysis of the proposed optimizations. Finally, a domain-specific visualization tool to explore astronomical SOMs is presented.

  20. Distributed Fast Self-Organized Maps for Massive Spectrophotometric Data Analysis †.

    Science.gov (United States)

    Dafonte, Carlos; Garabato, Daniel; Álvarez, Marco A; Manteiga, Minia

    2018-05-03

    Analyzing huge amounts of data becomes essential in the era of Big Data, where databases are populated with hundreds of Gigabytes that must be processed to extract knowledge. Hence, classical algorithms must be adapted towards distributed computing methodologies that leverage the underlying computational power of these platforms. Here, a parallel, scalable, and optimized design for self-organized maps (SOM) is proposed in order to analyze massive data gathered by the spectrophotometric sensor of the European Space Agency (ESA) Gaia spacecraft, although it could be extrapolated to other domains. The performance comparison between the sequential implementation and the distributed ones based on Apache Hadoop and Apache Spark is an important part of the work, as well as the detailed analysis of the proposed optimizations. Finally, a domain-specific visualization tool to explore astronomical SOMs is presented.

  1. Spectrophotometric determination of uranium and plutonium in nitric acid solutions at their co-presence

    International Nuclear Information System (INIS)

    Levakov, B.I.; Mishenev, V.B.; Nezgovorov, N.Yu.; Ryazanova, G.K.; Timofeev, G.A.

    1986-01-01

    The method of spectrophotometric determination of uranium (6) and plutonium (4) in nitric acid solutions is described. Uranium is determined by light absorption of the complex with arsenazo 3 in 0.05 mol/l nitric acid at λ=654 nm, plutonium - by light absorption of the complex with xylenol orange in 0.1 mol/l nitric acid at λ=540 nm. To disguise plutonium, tetravalent and certain trivalent elements DTPA is introduced into photometered solution for uranium determination. The relative root-mean square deviation of determination results does not exceed 0.03 in uranium concenration ranges 0.5-5 μg/ml, of plutonium -1-3 μg/ml

  2. 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.

  3. Spectrophotometric Determination of Metoprolol Tartrate in Pharmaceutical Dosage Forms on Complex Formation with Cu(II

    Directory of Open Access Journals (Sweden)

    Mustafa Cesme

    2011-06-01

    Full Text Available A new, simple, sensitive and accurate spectrophotometric method has been developed for the assay of metoprolol tartrate (MPT, which is based on the complexation of drug with copper(II [Cu(II] at pH 6.0, using Britton-Robinson buffer solution, to produce a blue adduct. The latter has a maximum absorbance at 675 nm and obeys Beer’s law within the concentration range 8.5-70 mg/mL. Regression analysis of the calibration data showed a good correlation coefficient (r = 0.998 with a limit of detection of 5.56 mg/mL. The proposed procedure has been successfully applied to the determination of this drug in its tablets. In addition, the spectral data and stability constant for the binuclear copper(II complex of MPT (Cu2MPT2Cl2 have been reported.

  4. Spectrophotometric determination of boron by solvent extraction with 2-hydroxy-2-methylbutyric acid and malachite green

    International Nuclear Information System (INIS)

    Sato, Shigeya; Uchikawa, Sumio

    1984-01-01

    A very simple and sensitive method for the spectrophotometric determination of boron was developed. Boron was found to react with 2-hydroxy-2-methylbutyric acid in weak acidic aqueous solution at room temperature to form a complex anion which can be extracted into chlorobenzene with malachite green in a single extraction; boron is determined indirectly by measuring the absorbance of malachite green in the extract at 629 nm. The calibration graph is linear over the range (7.50 x 10 -7 - 2.00 x 10 -5 ) mol dm -3 boron; the apparent molar absorptivity is 6.50 x 10 4 dm 3 mol -1 cm -1 . The method is applied to the determination of micro amounts of boron in natural waters with satisfactory results. (author)

  5. Spectrophotometric determination of boron by solvent extraction with 2-hydroxy-2-methylbutyric acid and malachite green

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Shigeya; Uchikawa, Sumio [Kumamoto Univ. (Japan). Faculty of Education

    1984-03-01

    A very simple and sensitive method for the spectrophotometric determination of boron was developed. Boron was found to react with 2-hydroxy-2-methylbutyric acid in weak acidic aqueous solution at room temperature to form a complex anion which can be extracted into chlorobenzene with malachite green in a single extraction; boron is determined indirectly by measuring the absorbance of malachite green in the extract at 629 nm. The calibration graph is linear over the range (7.50 x 10/sup -7/ - 2.00 x 10/sup -5/) mol dm/sup -3/ boron; the apparent molar absorptivity is 6.50 x 10/sup 4/ dm/sup 3/ mol/sup -1/ cm/sup -1/. The method is applied to the determination of micro amounts of boron in natural waters with satisfactory results.

  6. Spectrophotometric determination of zirconium with Chrome Azurol s in aqueous streams of nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Ganesh, S.; Velavendan, P.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

    2014-01-01

    A sensitive and reproducible spectrophotometric method for the determination of zirconium is developed. The method is based on the formation of stable bluish violet colour complex with Chrome Azurol S (CAS) with maximum absorption at 598 nm. The complex formed obeys Beer's law in the range of 1-7 μg/mL. Under optimum conditions, the sensitivity of the proposed method, (i.e. the detection limit), molar absorptivity and Sandell's sensitivity values are 2.42 μg/mL, 3.93 x10 3 L.Mol -1 .cm -1 and 2.54 x 10 -4 μg/cm 2 respectively. Relative standard deviation is less than 2% and correlation coefficient is 0.997. The present method is highly sensitive, selective, rapid and simple. It can be applied for the direct determination of zirconium in environmental, industrial, water and nuclear reprocessing samples. (author)

  7. Determination of free acidity in nuclear fuel reprocessing streams by fiber optic aided spectrophotometric technique

    International Nuclear Information System (INIS)

    Ganesh, S.; Velavendan, P.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

    2014-01-01

    A fiber optic aided spectrophotometric technique has been developed for the determination of free acidity in nuclear fuel reprocessing streams. The developed method is simple, accurate and applicable to all ranges of nitric acid and heavy metal concentrations relevant to the purex process. The method is based on the formation of yellow colour with an acid-sensitive indicator such as chrome azurol s, the intensity of yellow colour is proportional to the acid concentration. The system obeys Lambert-Beer's law at 455 nm in the range of acidity 1-10 M of nitric acid. The results obtained are reproducible with standard deviation 2% and relative error is less than 3%. The results obtained by the developed technique are in good agreement with those obtained by the standard procedure. This method is adaptable for remote operation and on-line monitoring. (author)

  8. Spectrophotometric determination of neodymium in mixture with lanthanum by eosin and 2,2'-dipyridyl

    International Nuclear Information System (INIS)

    Ovchar, L.A.; Poluehktov, N.S.

    1980-01-01

    The possibility of using rare earth complexes with eosin (EO) and 2.2-dipyridyl (DP) for spectrophotometric determination of some rare earths in the presence of the others. It has been out that the complexes are not extracted by organic solvents. The PH region of complex existence (approximately 6) and the relation of components in them (rare earths:DP:EO=1:2:3) are determined. The possibility has been shown of determining all the rare earts from praseodymium to lutetium and yttrium in a binary mixture with lanthanum based on different stability of the studied complexes. The method has been tested on the example of determining Nd 2 O 3 in a mixture with La 2 O 3 . The low limit of determined contents is 1-2%. The relative standard deviation is 0.035-0.17 [ru

  9. 2-Hydro-4-n-But oxypropiophenone Oxime as a spectrophotometric reagent for Fe (III)

    International Nuclear Information System (INIS)

    Purohit, K.; Desai, K.K.

    2006-01-01

    2-Hydro-4-n-But oxypropiophenone Oxime [Hipbone] has been synthesized and used for the spectrophotometric determination of Fe (III). The reagent gives purple coloured complex with Fe (III) in 50% alcoholic medium in pH range of 2.5-4.5. Beer's law is obeyed up to 23.1 ppm of Fe (III). Molar absorptivity and sandell's sensitivity at 500 nm of complex were found to be 7.062x 10 power2 lit.mol.cm and 0.079 ug of Fe (III)/cm respectively. Composition and stability constant have been determined. The reagent is successfully used for determination of Fe (III) in dolomite and in pharmaceutical sample. It is also used for the indirect determination of fluoride in tap water sample. (author)

  10. Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

    International Nuclear Information System (INIS)

    Hassan, S.S.M.; Mahmoud, W.H.

    1982-01-01

    Sensitive and reasonably selective methods are described for the spectrophotometric, potentiometric, and gravimetric determination of lanthanides using peri-dihydroxynaphthindenone as a novel chromogenic and precipitating reagent. The reagent forms a stable 1:2 (metal:reagent) type of complex with light lanthanides at pH 2-7 in 1:1 ethanol-water mixture. Low metal concentrations ( 4 L mol -1 cm -1 ) which obey Beer's law. Quantitative precipitation of the complexes from metal solutions of concentrations > 100 μg/mL permits both gravimetric quantitation by igniting the precipitates to the metal oxides and potentiometric titration of the excess reagent. Results with an average recovery of 98% (standard deviation 0.7%) are obtainable for 0.1 μg to 200 mg of all light lanthanides. Many foreign ions naturally occurring or frequently associated with lanthanides do not interfere or can be tolerated

  11. From thermometric to spectrophotometric kinetic-catalytic methods of analysis. A review.

    Science.gov (United States)

    Cerdà, Víctor; González, Alba; Danchana, Kaewta

    2017-05-15

    Kinetic-catalytic analytical methods have proved to be very easy and highly sensitive strategies for chemical analysis, that rely on simple instrumentation [1,2]. Molecular absorption spectrophotometry is commonly used as the detection technique. However, other detection systems, like electrochemical or thermometric ones, offer some interesting possibilities since they are not affected by the color or turbidity of the samples. In this review some initial experience with thermometric kinetic-catalytic methods is described, up to our current experience exploiting spectrophotometric flow techniques to automate this kind of reactions, including the use of integrated chips. Procedures for determination of inorganic and organic species in organic and inorganic matrices are presented. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Spectrophotometric determination of Tl carrier in 201Tl-TlCl injection

    International Nuclear Information System (INIS)

    Gong Quansheng; Jing Lie

    1997-01-01

    A simple and sensitive method for the spectrophotometric determination of carrier content (Thallium) in 201 Tl-TlCl injection is described. Thallium (I) is oxidised to Thallium (III) by aqueous bromine, then excess bromine is removed by adding sulfosalicylic acid. In buffer solution (NH 4 Cl-NH 4 OH) at pH 11.7 with the presence of emulsifier OP, thallium (III) and cadion form a complex having an absorption maximum at 469 nm with a molar absorptivity of 1.37 x 10 4 m 2 /mol. Beer's law is obeyed in the concentration range of 0-7 μg/5 mL. The effect of impurity elements in 201 Tl-TlCl injection is examined. It is an ideal method for the analysis of radioactive solution

  13. Indirect spectrophotometric determination of BIDA, DISIDA, DTPA and MDP in labelled compounds

    Energy Technology Data Exchange (ETDEWEB)

    Van der Walt, T.N.; Coetzee, P.P. (Rand Afrikaans Univ., Johannesburg (South Africa). Dept. of Chemistry); Fourie, P.J. (Atomic Energy Corp. of South Africa (Pty) Ltd., Pretoria (South Africa))

    1989-01-01

    N-(4-(n-butyl)acetanilide)iminodiacetic acid (BIDA), N-(2,6-diisopropylacetanilide)iminodiacetic acid (DISDA), diethylenetriaminepentaacetic acid (DTPA) and methylene diphosphonic acid (MDP) are used in labelling kits. The contents of BIDA, DISIDA or MDP of the {sup 99m}Tc-labelled compounds can be determined (indirectly) spectrophotometrically with copper, eriochrome cyanine R (ECC) and dodecyl-ethyldimethylammonium bromide (DEDA) in a sodium barbital buffered system at pH 8.5. The calibration curves obey Beer's Law from 0 to 40 {mu}g/25 mL for BIDA and DISIDA, 0 to 60 {mu}g/25 mL for DTPA and 0 to 100 {mu}g/10 mL for MDP. (author).

  14. Indirect spectrophotometric determination of BIDA, DISIDA, DTPA and MDP in labelled compounds

    International Nuclear Information System (INIS)

    Van der Walt, T.N.; Coetzee, P.P.

    1989-01-01

    N-(4-(n-butyl)acetanilide)iminodiacetic acid (BIDA), N-(2,6-diisopropylacetanilide)iminodiacetic acid (DISDA), diethylenetriaminepentaacetic acid (DTPA) and methylene diphosphonic acid (MDP) are used in labelling kits. The contents of BIDA, DISIDA or MDP of the 99m Tc-labelled compounds can be determined (indirectly) spectrophotometrically with copper, eriochrome cyanine R (ECC) and dodecyl-ethyldimethylammonium bromide (DEDA) in a sodium barbital buffered system at pH 8.5. The calibration curves obey Beer's Law from 0 to 40 μg/25 mL for BIDA and DISIDA, 0 to 60 μg/25 mL for DTPA and 0 to 100 μg/10 mL for MDP. (author)

  15. Effect of some colloid surfactants on spectrophotometric characteristics of metal chelates with chromophore organic reagents

    International Nuclear Information System (INIS)

    Chernova, R.K.

    1977-01-01

    Theoretical regularities and prospects of using surface active substances (SAS) in spectrophotometric determination of metal ions (including ions of rare-earth elements, transition metals, Be(3)) with chromophore chelating reagents were investigated. The chromophore reagents investigated were pyrocatechol violet, phenolcarboxylic acids of the triarylmethane series, fluorones, phthalexones and azo-compounds. As SAS certain long-chain quaternary ammonium and pyridinium salts (LQAS) were employed. From the results reported it follows that the introduction of LQAS in the system of Mesup(n+)-chromophore reagent is a rather effective method of enhancing the contrast rendition and, in some cases, the sensitivity and selectivity of the reagents. Explanations are suggested as to the factors which cause the changes observed in the contrast of the reactions in the presence of SAS; the underlying phenomena are the ligand-ligand interactions between the organic reagents and SAS and solubilization processes of the reaction products by the micelles of SAS

  16. Building-up a database of spectro-photometric standards from the UV to the NIR

    Science.gov (United States)

    Vernet, J.; Kerber, F.; Mainieri, V.; Rauch, T.; Saitta, F.; D'Odorico, S.; Bohlin, R.; Ivanov, V.; Lidman, C.; Mason, E.; Smette, A.; Walsh, J.; Fosbury, R.; Goldoni, P.; Groot, P.; Hammer, F.; Kaper, L.; Horrobin, M.; Kjaergaard-Rasmussen, P.; Royer, F.

    2010-11-01

    We present results of a project aimed at establishing a set of 12 spectro-photometric standards over a wide wavelength range from 320 to 2500 nm. Currently no such set of standard stars covering the near-IR is available. Our strategy is to extend the useful range of existing well-established optical flux standards (Oke 1990, Hamuy et al. 1992, 1994) into the near-IR by means of integral field spectroscopy with SINFONI at the VLT combined with state-of-the-art white dwarf stellar atmospheric models (TMAP, Holberg et al. 2008). As a solid reference, we use two primary HST standard white dwarfs GD71 and GD153 and one HST secondary standard BD+17 4708. The data were collected through an ESO “Observatory Programme” over ~40 nights between February 2007 and September 2008.

  17. Spectrophotometric determination of U(vi) in 30% tbp using dibenzoyl methane (DBM) and methanol (abstract)

    International Nuclear Information System (INIS)

    Islam, N.; Naqvi, A.

    2011-01-01

    The Spectrophotometric method for the determination of trace amount of Uranium in aqueous and organic samples has been developed. The method is proved very accurate and precise for rapid determination of Uranium with Dibenzoyl Methane (DBM) in Methanol medium instead of Pyridine medium. The maximum absorbance occurs at 410 nm with a molar absorptivity of 4.5 x 104 L.mole/sup -1/.cm/sup -1/.The linear calibration curve through the point of origin was obtained up to 10 mu gm L/sup -1/ of Uranium (VI). The relative standard deviation is +- 2%. In case of aqueous samples extraction procedure is adopted to obtain organic phase while organic samples are treated as such. (author)

  18. Development and Validation of UV Spectrophotometric Method For Estimation of Dolutegravir Sodium in Tablet Dosage Form

    International Nuclear Information System (INIS)

    Balasaheb, B.G.

    2015-01-01

    A simple, rapid, precise and accurate spectrophotometric method has been developed for quantitative analysis of Dolutegravir sodium in tablet formulations. The initial stock solution of Dolutegravir sodium was prepared in methanol solvent and subsequent dilution was done in water. The standard solution of Dolutegravir sodium in water showed maximum absorption at wavelength 259.80 nm. The drug obeyed Beer-Lamberts law in the concentration range of 5-40 μg/ mL with coefficient of correlation (R"2) was 0.9992. The method was validated as per the ICH guidelines. The developed method can be adopted in routine analysis of Dolutegravir sodium in bulk or tablet dosage form and it involves relatively low cost solvents and no complex extraction techniques. (author)

  19. Development and application of spectrophotometric method for the determination of cefaclor in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Asad Raza

    2009-01-01

    Full Text Available A simple, fast and sensitive spectrophotometric method for the determination of cefaclor in pharmaceutical raw and dosage forms based on reaction with ninhydrin is developed, optimized and validated. The purple color (Ruhemenn's purple that resulted from the reaction was stabilized and measured at 560 nm. Beer's law is obeyed in the concentration range of 4-80 µg mL-1 with molar absorptivity of 1.42 × 10(5 L mole-1 cm-1. All variables including the reagent concentration, heating time, reaction temperature, color stability period, and cefaclor/ninhydrin ratio were studied in order to optimize the reaction conditions. No interference was observed from common pharmaceutical adjuvant. The developed method is easy to use, accurate and highly cost-effective for routine studies relative to HPLC and other techniques.

  20. Cloud point extraction, preconcentration and spectrophotometric determination of nickel in water samples using dimethylglyoxime

    Directory of Open Access Journals (Sweden)

    Morteza Bahram

    2013-01-01

    Full Text Available A new and simple method for the preconcentration and spectrophotometric determination of trace amounts of nickel was developed by cloud point extraction (CPE. In the proposed work, dimethylglyoxime (DMG was used as the chelating agent and Triton X-114 was selected as a non-ionic surfactant for CPE. The parameters affecting the cloud point extraction including the pH of sample solution, concentration of the chelating agent and surfactant, equilibration temperature and time were optimized. Under the optimum conditions, the calibration graph was linear in the range of 10-150 ng mL-1 with a detection limit of 4 ng mL-1. The relative standard deviation for 9 replicates of 100 ng mL-1 Ni(II was 1.04%. The interference effect of some anions and cations was studied. The method was applied to the determination of Ni(II in water samples with satisfactory results.

  1. Development of microwave assisted spectrophotometric method for the determination of glucose

    Science.gov (United States)

    Ali, Asif; Hussain, Zahid; Arain, Muhammad Balal; Shah, Nasrullah; Khan, Khalid Mohammad; Gulab, Hussain; Zada, Amir

    2016-01-01

    A spectrophotometric method was developed based on the microwave assisted synthesis of Maillard product. Various conditions of the reaction were optimized by varying the relative concentration of the reagents, operating temperature and volume of solutions used in the reaction in the microwave synthesizer. The absorbance of the microwave synthesized Maillard product was measured in the range of 360-740 nm using UV-Visible spectrophotometer. Based on the maximum absorbance, 370 nm was selected as the optimum wave length for further studies. The LOD and LOQ of glucose was found 3.08 μg mL- 1 and 9.33 μg mL- 1 with standard deviation of ± 0.05. The developed method was also applicable to urine sample.

  2. Extractive-spectrophotometric determination of disopyramide and irbesartan in their pharmaceutical formulation

    Science.gov (United States)

    Abdellatef, Hisham E.

    2007-04-01

    Picric acid, bromocresol green, bromothymol blue, cobalt thiocyanate and molybdenum(V) thiocyanate have been tested as spectrophotometric reagents for the determination of disopyramide and irbesartan. Reaction conditions have been optimized to obtain coloured comoplexes of higher sensitivity and longer stability. The absorbance of ion-pair complexes formed were found to increases linearity with increases in concentrations of disopyramide and irbesartan which were corroborated by correction coefficient values. The developed methods have been successfully applied for the determination of disopyramide and irbesartan in bulk drugs and pharmaceutical formulations. The common excipients and additives did not interfere in their determination. The results obtained by the proposed methods have been statistically compared by means of student t-test and by the variance ratio F-test. The validity was assessed by applying the standard addition technique. The results were compared statistically with the official or reference methods showing a good agreement with high precision and accuracy.

  3. Spectrophotometric determination of uranium and thorium with arsenazo III in the flow injection system

    International Nuclear Information System (INIS)

    Andrade, M. das G.M. de.

    1986-12-01

    A simple system for flow injection analysis (FIA) with double confluence was built using a filter photocolorimeter, an analogic potentiometer, 'plexiglass' flow cuvettes, polyethylene colls and tubes, 'plexiglass' commuter and peristaltic pump to introduce solutions and gravity as flow source. The system was dimensioned and studied using only Arsenazo III solutions. Spectrophotometric methods for uranium and thorium using Arsenazo III were studied using a scanning spectrophotometer and after chosing adequate red filter, adapted to photocolorimetry using flow cuvettes and FIA. Synthetic samples, phosphate rock, and process samples from uranium recovery of dolomites were analysed. Rocks of Morro do Ferro (MG, Brazil), Caldasite (Baddeleyte + Zirconite), Zirconite, Monazite from a program for certification and certified rocks (Dunite DC-1, CANMET) were analysed without chemical separation of Th (IV) and with ion exchange separation in semi-micro columns of cation exchange resin (Dowex 50). (Author) [pt

  4. Financial Derivatives

    DEFF Research Database (Denmark)

    Wigan, Duncan

    2013-01-01

    Contemporary derivatives mark the development of capital and constitute a novel form of ownership. By reconfiguring the temporal, spatial and legal character of ownership derivatives present a substantive challenge to the tax collecting state. While fiscal systems are nationally bounded...... and inherently static, capital itself is unprecedentedly mobile, fluid and fungible. As such derivatives raise the specter of ‘financial weapons of mass destruction’....

  5. Financial Derivatives

    OpenAIRE

    Janečková, Alena

    2011-01-01

    1 Abstract/ Financial derivatives The purpose of this thesis is to provide an introduction to financial derivatives which has been, from the legal perspective, described in a not satisfactory manner as quite little literature that can be found about this topic. The main objectives of this thesis are to define the term "financial derivatives" and its particular types and to analyse legal nature of these financial instruments. The last objective is to try to draft future law regulation of finan...

  6. The reliability analysis of cutting tools in the HSM processes

    OpenAIRE

    W.S. Lin

    2008-01-01

    Purpose: This article mainly describe the reliability of the cutting tools in the high speed turning by normaldistribution model.Design/methodology/approach: A series of experimental tests have been done to evaluate the reliabilityvariation of the cutting tools. From experimental results, the tool wear distribution and the tool life are determined,and the tool life distribution and the reliability function of cutting tools are derived. Further, the reliability ofcutting tools at anytime for h...

  7. Reliability issues in PACS

    Science.gov (United States)

    Taira, Ricky K.; Chan, Kelby K.; Stewart, Brent K.; Weinberg, Wolfram S.

    1991-07-01

    Reliability is an increasing concern when moving PACS from the experimental laboratory to the clinical environment. Any system downtime may seriously affect patient care. The authors report on the several classes of errors encountered during the pre-clinical release of the PACS during the past several months and present the solutions implemented to handle them. The reliability issues discussed include: (1) environmental precautions, (2) database backups, (3) monitor routines of critical resources and processes, (4) hardware redundancy (networks, archives), and (5) development of a PACS quality control program.

  8. Reliability Parts Derating Guidelines

    Science.gov (United States)

    1982-06-01

    226-30, October 1974. 66 I, 26. "Reliability of GAAS Injection Lasers", De Loach , B. C., Jr., 1973 IEEE/OSA Conference on Laser Engineering and...Vol. R-23, No. 4, 226-30, October 1974. 28. "Reliability of GAAS Injection Lasers", De Loach , B. C., Jr., 1973 IEEE/OSA Conference on Laser...opnatien ot 󈨊 deg C, mounted on a 4-inach square 0.250~ inch thick al~loy alum~nusi panel.. This mounting technique should be L~ ken into cunoidur~tiou

  9. Study of extraction-spectrophotometric micro-determination of boron with methylene blue and its application

    International Nuclear Information System (INIS)

    Zhu Daohong

    1990-08-01

    A sensitive extraction-spectrophotometric method for microdetermination of boron with methylene blue was investigated. The method was based on the extraction of a BF 4 - -methylene blue complex into dichloroethane. Boron was determined directly by measuring the absorbance at 658 nm. The calibration graph was linear over the range of 2.5 x 10 -9 to 8 x 10 -8 g/mL. The blank, mechanism of the reactions, interference of other ions and some optimum conditions of the method were studied in detail. The main source of the blank resulted from methylene blue and the complex of F - -methylene blue. In order to reduce the blank, the amounts of methylene blue, H 2 SO 4 and HF were used as less as possible. Only one to one complex BF 4 - -methylene blue was formed in the medium of H 2 SO 4 . About 90% of methylene blue and F - -methylene blue complex was removre with 5 ml of water and only a little amount of BF 4 -methylene blue complex was decomposed. The extraction-spectrophotometric method with methylene blue was first applied to the microdetermination of boron in sodium metal and UF 6 . The sample of sodium metal was taken and weighed in the glovebox filled with argon. Then sodium metal was oxidized, hydrolyzed, netralized and fluorizated with H 2 O, H 2 SO 4 and HF, respectively. The 0.5 ppm of boron in sodium metal was determined with a relative error about ±4%. This method can be applied to the determination of boron in sodium metal, sodium sulfate and sodium hydroxide at diffeent grades. The species of boron in the hydrolysate of UF 6 is BF 4 - anion, so the sample can be directly analyzed. Boron contents in the range of 0.1 to 0.5 ppm was determined with a relative error about ±3%. Six samples could be analysed in 2h

  10. Measurement of peroxisomal enzyme activities in the liver of brown trout (Salmo trutta, using spectrophotometric methods

    Directory of Open Access Journals (Sweden)

    Resende Albina D

    2003-03-01

    Full Text Available Abstract Background This study was aimed primarily at testing in the liver of brown trout (Salmo trutta spectrophotometric methods previously used to measure the activities of catalase and hydrogen peroxide producing oxidases in mammals. To evaluate the influence of temperature on the activities of those peroxisomal enzymes was the second objective. A third goal of this work was the study of enzyme distribution in crude cell fractions of brown trout liver. Results The assays revealed a linear increase in the activity of all peroxisomal enzymes as the temperature rose from 10° to 37°C. However, while the activities of hydrogen peroxide producing oxidases were strongly influenced by temperature, catalase activity was only slightly affected. A crude fraction enriched with peroxisomes was obtained by differential centrifugation of liver homogenates, and the contamination by other organelles was evaluated by the activities of marker enzymes for mitochondria (succinate dehydrogenase, lysosomes (aryl sulphatase and microsomes (NADPH cytochrome c reductase. For peroxisomal enzymes, the activities per mg of protein (specific activity in liver homogenates were strongly correlated with the activities per g of liver and with the total activities per liver. These correlations were not obtained with crude peroxisomal fractions. Conclusions The spectrophotometric protocols originally used to quantify the activity of mammalian peroxisomal enzymes can be successfully applied to the study of those enzymes in brown trout. Because the activity of all studied peroxisomal enzymes rose in a linear mode with temperature, their activities can be correctly measured between 10° and 37°C. Probably due to contamination by other organelles and losses of soluble matrix enzymes during homogenisation, enzyme activities in crude peroxisomal fractions do not correlate with the activities in liver homogenates. Thus, total homogenates will be used in future seasonal and

  11. Kinetic spectrophotometric method for the determination of perindopril erbumine in pure and commercial dosage forms

    Directory of Open Access Journals (Sweden)

    Nafisur Rahman

    2017-02-01

    Full Text Available A kinetic spectrophotometric method has been developed for the determination of perindopril erbumine in pure and commercial dosage forms. The method is based on the reaction of drug with potassium permanganate in alkaline medium at room temperature (30 ± 1 °C. The reaction was followed spectrophotometrically by measuring the increase in absorbance with time at 603 nm and the initial rate, fixed time (at 8.0 min and equilibrium time (at 90.0 min methods were adopted for constructing the calibration graphs. All the calibration graphs are linear in the concentration range of 5.0–50.0 μg/ml. The limits of detection for initial rate, fixed time and equilibrium time methods were 0.752, 0.882 and 1.091 μg/ml, respectively. The activation parameters such as Ea, ΔH‡, ΔS‡ and ΔG‡ were also determined for the reaction and found to be 60.93 kJ/mol, 56.45 kJ/mol, 74.16 J/K mol and −6.53 kJ/mol, respectively. The variables were optimized and the proposed methods are validated as per ICH guidelines. The method has been further applied to the determination of perindopril erbumine in commercial dosage forms. The analytical results of the proposed methods when compared with those of the reference method show no significant difference in accuracy and precision and have acceptable bias.

  12. New potentiometric and spectrophotometric methods for the determination of dextromethorphan in pharmaceutical preparations.

    Science.gov (United States)

    Elmosallamy, Mohamed A F; Amin, Alaa S

    2014-01-01

    New, simple and convenient potentiometric and spectrophotometric methods are described for the determination of dextromethorphan hydrobromide (DXM) in pharmaceutical preparations. The potentiometric technique is based on developing a potentiometric sensor incorporating the dextromethorphan tetrakis(p-chlorophenyl)borate ion-pair complex as an electroactive species in a plasticized PVC matrix membrane with o-nitophenyl octyl ether or dioctyl phthalate. The sensor shows a rapid near Nernstian response of over 1 × 10(-5) - 1 × 10(-2) mol L(-1) dextromethorphan in the pH range of 3.0 - 9.0. The detection limit is 2 × 10(-6) mol L(-1) DXM and the response time is instantaneous (2 s). The proposed spectrophotometric technique involves the reaction of DXM with eriochrom black T (EBT) to form an ion-associate complex. Solvent extraction is used to improve the selectivity of the method. The optimal extraction and reaction conditions have been studied, and the analytical characteristics of the method have been obtained. Linearity is obeyed in the range of 7.37 - 73.7 × 10(-5) mol L(-1) DXM, and the detection limit of the method is 1.29 × 10(-5) mol L(-1). The relative standard deviation (RSD) and relative error for six replicate measurements of 3.685 × 10(-4) mol L(-1) are 0.672 and 0.855%, respectively. The interference effect of some excepients has also been tested. The drug contents in pharmaceutical preparations were successfully determined by the proposed methods by applying the standard-addition technique.

  13. A modified spectrophotometric assay to estimate deglycosylation of steroidal saponin to sapogenin by mixed ruminal microbes.

    Science.gov (United States)

    Wang, Yuxi; McAllister, Tim A

    2010-08-30

    The lack of a method for measuring deglycosylation of saponins in ruminal fluid has limited the ability to investigate the impact of these compounds on rumen microorganisms. A simple spectrophotometric assay was adapted and a protocol developed to enable measurement of steroidal saponin and sapogenin in ruminal fluid. The procedure was used for in vitro determination of deglycosylation activity of rumen bacteria obtained from cattle fed or not fed Yucca schidigera saponin, and to determine the relative deglycosylase activities of extracellular and cell-associated enzymes from ruminal content. Modifications to the spectrophotometric assay (i.e. heating time shortened to 10 min and 0.5 mL dH(2)O added to the reaction mixture) improved the stability of the optical density (425 nm) of the chromophore for up to 24 h post-reaction. Centrifugation (12 000 x g, 20 min) enabled differential estimations of steroidal saponin and sapogenin in ruminal fluid. Steroidal saponin added to defaunated ruminal fluid (dRF) or clarified ruminal fluid (cRF) was recovered completely from the mixture as saponin + sapogenin (99.1% and 100.6%, respectively), whereas saponin recovery from the supernatant of dRF was greatly reduced (P ruminal extracellular enzyme preparation was recoverable in supernatant after 24 h, compared with only 26-32% remaining in supernatant from incubation with a cell-associated enzymes fraction. Mixed rumen bacteria deglycosylate steroidal saponin to sapogenin, at activity levels unaffected by prior exposure to saponin, but they were unable to degrade the sapogenin core structure. Deglycosylation activity occurred primarily in the cell-associated enzyme fraction of ruminal content. Copyright (c) 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.

  14. IRT-Estimated Reliability for Tests Containing Mixed Item Formats

    Science.gov (United States)

    Shu, Lianghua; Schwarz, Richard D.

    2014-01-01

    As a global measure of precision, item response theory (IRT) estimated reliability is derived for four coefficients (Cronbach's a, Feldt-Raju, stratified a, and marginal reliability). Models with different underlying assumptions concerning test-part similarity are discussed. A detailed computational example is presented for the targeted…

  15. A Latent Class Approach to Estimating Test-Score Reliability

    Science.gov (United States)

    van der Ark, L. Andries; van der Palm, Daniel W.; Sijtsma, Klaas

    2011-01-01

    This study presents a general framework for single-administration reliability methods, such as Cronbach's alpha, Guttman's lambda-2, and method MS. This general framework was used to derive a new approach to estimating test-score reliability by means of the unrestricted latent class model. This new approach is the latent class reliability…

  16. Reliability analysis of RC containment structures under combined loads

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Kagami, S.

    1984-01-01

    This paper discusses a reliability analysis method and load combination design criteria for reinforced concrete containment structures under combined loads. The probability based reliability analysis method is briefly described. For load combination design criteria, derivations of the load factors for accidental pressure due to a design basis accident and safe shutdown earthquake (SSE) for three target limit state probabilities are presented

  17. Macroscopic travel time reliability diagrams for freeway networks

    NARCIS (Netherlands)

    Tu, H.; Li, H.; Van Lint, J.W.C.; Knoop, V.L.; Sun, L.

    2013-01-01

    Travel time reliability is considered to be one of the key indicators of transport system performance. Knowledge of the mechanisms of travel time unreliability enables the derivation of explanatory models with which travel time reliability can be predicted and utilized in traffic management.

  18. Spectrophotometric Quantification of Flavonoids in Herbal Material, Crude Extract, and Fractions from Leaves of Eugenia uniflora Linn.

    Science.gov (United States)

    Ramos, Rhayanne T M; Bezerra, Isabelle C F; Ferreira, Magda R A; Soares, Luiz Alberto Lira

    2017-01-01

    The traditional use of Eugenia uniflora L. ("Pitanga") is reported due to several properties, which have often been related to its flavonoid content. The aim was to evaluate analytical procedures for quantification of total flavonoids content (TFCs) by ultraviolet-visible (UV-Vis) spectrophotometry in the herbal material (HM), crude extract (CE), and fractions from leaves of E. uniflora . The method for quantification of flavonoids after complexation with aluminum chloride (AlCl 3 ) was evaluated: amount of sample (0.25-1.5 g); solvent (40%-80% ethanol); reaction time and AlCl 3 concentration (2.5%-7.5%). The procedures by direct dilution (DD) and after acid hydrolysis (AH) were used and validated for HM and CE and applied to the aqueous fraction (AqF), hexane fraction, and ethyl acetate fractions (EAF). The ideal conditions of analysis were ethanol 80% as solvent; 0.5 g of sample; λmax of 408 (DD) and 425 nm (AH); 25 min after addition of AlCl 3 5%. The procedures validated for standards and samples showed linearity ( R 2 > 0.99) with limit of detection and limit of quantification between 0.01 and 0.17 mg/mL (rutin and quercetin); and 0.03 and 0.09 mg/mL (quercetin), for DD and AH, respectively. The procedures were accurate (detect, practice, and repair 90%), and stable under robustness conditions (luminosity, storage, reagents, and equipment). The TFCs in AqF and EAF were 0.65 g% and 17.72 g%, calculated as rutin. UV-Vis methods for quantification of TFC in HM, CE, and fractions from leaves of E. uniflora were suitably validated. Regarding the analysis of fractions, the EAF achieved enrichment of about nine times in the content of flavonoids. The total flavonoids content (TFCs) of herbal material, crude extract, and fractions from Eugenia uniflora can be quantified by ultraviolet-visibleThe spectrophotometric methods (direct dilution and acid hydrolysis) were reproducible and able to quantify TFC in raw material and derivatives from leaves of E. uniflora Higher

  19. A spectrophotometric study of aqueous Au(III) halide-hydroxide complexes at 25-80 °C

    Science.gov (United States)

    Usher, Al; McPhail, D. C.; Brugger, Joël

    2009-06-01

    The mobility and transport of gold in low-temperature waters and brines is affected by the aqueous speciation of gold, which is sensitive in particular to pH, oxidation and halide concentrations. In this study, we use UV-Vis spectrophotometry to identify and measure the thermodynamic properties of Au(III) aqueous complexes with chloride, bromide and hydroxide. Au(III) forms stable square planar complexes with hydroxide and halide ligands. Based on systematic changes in the absorption spectra of solutions in three binary systems NaCl-NaBr, NaCl-NaOH and NaBr-NaOH at 25 °C, we derived log dissociation constants for the following mixed and end-member halide and hydroxide complexes: [AuCl 3Br] -, [AuCl 2Br 2] -, [AuBr 3Cl] - and [AuBr 4] -; [AuCl 3(OH)] -, [AuCl 2(OH) 2] -, [AuCl(OH) 3] - and [Au(OH) 4] -; and [AuBr 3(OH)] -, [AuBr 2(OH) 2] - and [AuBr(OH) 3] -. These are the first reported results for the mixed chloride-bromide complexes. Increasing temperature to 80 °C resulted in an increase in the stability of the mixed chloride-bromide complexes, relative to the end-member chloride and bromide complexes. For the [AuCl (4-n)(OH) n] - series of complexes ( n = 0-4), there is an excellent agreement between our spectrophotometric results and previous electrochemical results of Chateau et al. [Chateau et al. (1966)]. In other experiments, the iodide ion (I -) was found to be unstable in the presence of Au(III), oxidizing rapidly to I 2(g) and causing Au to precipitate. Predicted Au(III) speciation indicates that Au(III) chloride-bromide complexes can be important in transporting gold in brines with high bromide-chloride ratios (e.g., >0.05), under oxidizing (atmospheric), acidic (pH < 5) conditions. Native gold solubility under atmospheric oxygen conditions is predicted to increase with decreasing pH in acidic conditions, increasing pH in alkaline conditions, increasing chloride, especially at acid pH, and increasing bromide for bromide/chloride ratios greater than 0

  20. System reliability developments in structural engineering

    International Nuclear Information System (INIS)

    Moses, F.

    1982-01-01

    Two major limitations occur in present structural design code developments utilizing reliability theory. The notional system reliabilities may differ significantly from calibrated component reliabilities. Secondly, actual failures are often due to gross errors not reflected in most present code formats. A review is presented of system reliability methods and further new concepts are developed. The incremental load approach for identifying and expressing collapse modes is expanded by employing a strategy to identify and enumerate the significant structural collapse modes. It further isolates the importance of critical components in the system performance. Ductile and brittle component behavior and strength correlation is reflected in the system model and illustrated in several examples. Modal combinations for the system reliability are also reviewed. From these developments a system factor can be addended to component safety checking equations. Values may be derived from system behavior by substituting in a damage model which accounts for the response range from component failure to collapse. Other strategies are discussed which emphasize quality assurance during design and in-service inspection for components whose behavior is critical to the system reliability. (Auth.)