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Sample records for fluorescence uranium determination

  1. Uranium determination at ppb levels by X-ray fluorescence after its preconcentration on polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, M.S.; Domingues, M.D.L.F.; Mantovano, J.L.; Filho, E.Q.S. [Instituto de Engenharia Nuclear, CNEN-RJ, CP 68550, 21945-590 (Brazil)

    1998-12-28

    A sensitive method based on the preconcentration of uranium on powdered polyurethane foam (PUF) has been developed to determinate this element in water samples by X-ray florescence. Uranium at ppb levels was sorbed as the salicylate complex on powdered PUF at pH 4.0. The resulting PUF was filtered through a filter paper and used for X-ray fluorescence measurements. For 50 {mu}g/l of uranium the coefficient of variation for five measurements is 5% and the detection limit is 5.5 {mu}g/l. The interference level of various ions and ligands was studied and optimum conditions were developed to determine uranium in reference materials, waste water, mine drainage, and sea water. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Fluorescence uranium determination; Determinacion de uranio por fluorescencia. I. Proyecto de equipo y comprobacion

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R.; Crus Castillo, F. de la; Barrera Pinero, R.

    1960-07-01

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs.

  3. X-ray fluorescence-based method for the quantitative determination of uranium in the aqueous solutions

    Science.gov (United States)

    Dubrovka, S.; Chursin, S.; Verkhoturova, V.

    2017-01-01

    Currently, one of the important issues in the field of nuclear technology is providing special handling with respect to nuclear materials, due to their energy and commercial significancy, as well as their potential radiation contamination threat. There is a necessity to have information about the full qualitative and quantitative composition of the sample as a part of special handling with nuclear materials. Spectrometric methods solve this problem effectively. One of these methods is the X-ray fluorescence analysis, which is fast, nondestructive and environmentally friendly with a high accuracy and reproducibility of the results. Development of uranium quantitative determination method in aqueous solutions to solve the problems of accounting and control of nuclear materials is the subject of research in this article. The development of the uranium concentration determination method in the aqueous solutions of uranyl nitrate UO2(NO3)2 was carried out using Spectroscan MAKC-G - wavelength dispersive crystal diffraction XRF spectrometer.

  4. Determination of trace uranium by resonance fluorescence method coupled with photo-catalytic technology and dual cloud point extraction

    Science.gov (United States)

    Li, Jiekang; Li, Guirong; Han, Qian

    2016-12-01

    In this paper, two kinds of salophens (Sal) with different solubilities, Sal1 and Sal2, have been respectively synthesized, and they all can combine with uranyl to form stable complexes: [UO22 +-Sal1] and [UO22 +-Sal2]. Among them, [UO22 +-Sal1] was used as ligand to extract uranium in complex samples by dual cloud point extraction (dCPE), and [UO22 +-Sal2] was used as catalyst for the determination of uranium by photocatalytic resonance fluorescence (RF) method. The photocatalytic characteristic of [UO22 +-Sal2] on the oxidized pyronine Y (PRY) by potassium bromate which leads to the decrease of RF intensity of PRY were studied. The reduced value of RF intensity of reaction system (ΔF) is in proportional to the concentration of uranium (c), and a novel photo-catalytic RF method was developed for the determination of trace uranium (VI) after dCPE. The combination of photo-catalytic RF techniques and dCPE procedure endows the presented methods with enhanced sensitivity and selectivity. Under optimal conditions, the linear calibration curves range for 0.067 to 6.57 ng mL- 1, the linear regression equation was ΔF = 438.0 c (ng mL- 1) + 175.6 with the correlation coefficient r = 0.9981. The limit of detection was 0.066 ng mL- 1. The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-103.5%. The mechanisms of the indicator reaction and dCPE are discussed.

  5. Determination of trace uranium by resonance fluorescence method coupled with photo-catalytic technology and dual cloud point extraction.

    Science.gov (United States)

    Li, Jiekang; Li, Guirong; Han, Qian

    2016-12-01

    In this paper, two kinds of salophens (Sal) with different solubilities, Sal1 and Sal2, have been respectively synthesized, and they all can combine with uranyl to form stable complexes: [UO2(2+)-Sal1] and [UO2(2+)-Sal2]. Among them, [UO2(2+)-Sal1] was used as ligand to extract uranium in complex samples by dual cloud point extraction (dCPE), and [UO2(2+)-Sal2] was used as catalyst for the determination of uranium by photocatalytic resonance fluorescence (RF) method. The photocatalytic characteristic of [UO2(2+)-Sal2] on the oxidized pyronine Y (PRY) by potassium bromate which leads to the decrease of RF intensity of PRY were studied. The reduced value of RF intensity of reaction system (ΔF) is in proportional to the concentration of uranium (c), and a novel photo-catalytic RF method was developed for the determination of trace uranium (VI) after dCPE. The combination of photo-catalytic RF techniques and dCPE procedure endows the presented methods with enhanced sensitivity and selectivity. Under optimal conditions, the linear calibration curves range for 0.067 to 6.57ngmL(-1), the linear regression equation was ΔF=438.0 c (ngmL(-1))+175.6 with the correlation coefficient r=0.9981. The limit of detection was 0.066ngmL(-1). The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-103.5%. The mechanisms of the indicator reaction and dCPE are discussed.

  6. Separation and determination of trace uranium using a double-receptor sandwich supramolecule method based on immobilized salophen and fluorescence labeled oligonucleotide

    Energy Technology Data Exchange (ETDEWEB)

    Wu Minlong [College of Chemistry and Chemical Engineering, University of South China, Hengyang, Hunan 421001 (China); Liao Lifu, E-mail: lf_liao@yahoo.com.cn [College of Chemistry and Chemical Engineering, University of South China, Hengyang, Hunan 421001 (China); Zhao Minmin; Lin Yingwu; Xiao Xilin; Nie Changming [College of Chemistry and Chemical Engineering, University of South China, Hengyang, Hunan 421001 (China)

    2012-06-04

    Highlights: Black-Right-Pointing-Pointer We report a double-receptor sandwich method for separating and determining uranium. Black-Right-Pointing-Pointer One receptor used for separating uranium is an immobilized salophen. Black-Right-Pointing-Pointer Another used for determining uranium is a fluorescence labeled oligonucleotide. Black-Right-Pointing-Pointer The method utilizes the formation of supramolecule oligonucleotide-uranyl-salophen. Black-Right-Pointing-Pointer It has the advantages of high selectivity, high sensitivity and good stability. - Abstract: A double-receptor sandwich supramolecule method for the separation and determination of trace uranium was proposed in this paper. One receptor is a salophen which can react with uranyl to form a uranyl-salophen complex, and another receptor is an oligonucleotide which can bind uranyl to form oligonucleotide-uranyl-salophen supramolecule. The salophen was immobilized on the surface of silica gel particles and used as the solid phase receptor for separating uranium from solution. The oligonucleotide was labeled with a fluorescent group and used as the labeled receptor for quantitatively analyzing uranium. In the procedure of separation and determination, uranyl ion was first combined with the solid phase receptor and then conjugated with the labeled receptor to form the sandwich-type supramolecule. The labeled receptor in the sandwich supramolecule was then eluted and determined by fluorescence analysis. The experimental results demonstrate that this method has a number of advantages such as high selectivity, excellent pre-concentration capability, high sensitivity, good stability and low cost. Under optimal conditions, the linear range for the detection of uranium is 0.5-30.0 ng mL{sup -1} with a detection limit of 0.2 ng mL{sup -1}. The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-105.5%.

  7. Determination of niobium, tantalum, and uranium in tantalite-columbite ores by X-ray fluorescence spectrometry; Application de la spectrometrie de fluorescence de rayos X a la determination de niobium, tantale et uranium dans niobiotantalites

    Energy Technology Data Exchange (ETDEWEB)

    Latorre, O.; Bermudez Polonio, J.

    1964-07-01

    A simple and quick procedure is carried out to determine niobium, tantalum and uranium employing the internal standard technique; zinc as internal standard for tantalum and molybdenum for niobium and uranium were selected. Some inter element effects were studied and the ratios. (Author)

  8. Standard test method for determination of low concentrations of uranium in oils and organic liquids by X-ray fluorescence

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers the steps necessary for the preparation and analysis by X-ray fluorescence (XRF) of oils and organic solutions containing uranium. Two different preparation techniques are described. 1.2 The procedure is valid for those solutions containing 20 to 2000 μg uranium per mL as presented to the spectrometer for the solution technique and 200 to 50 000 μg uranium per g for the pellet technique. 1.3 This test method requires the use of an appropriate internal standard. Care must be taken to ascertain that samples analyzed by this test method do not contain the internal standard or that this contamination, whenever present, has been corrected for mathematically. Such corrections are not addressed in this procedure. Care must be taken that the internal standard and sample medium are compatible; that is, samples must be miscible with tri-n-butyl phosphate (TBP) and must not remove the internal standard from solution. Alternatively, a scatter line may be used as the internal standard. 1....

  9. X-Ray Fluorescence Spectrometry. II Determination of Uranium in ores; Espectrometria de fluorescencia de Rayos X. II-Aplicacion a la determinacion de uranio en minerales

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez Polonio, J.; Crus Castillo, F. de la; Fernandez Cellini, R.

    1961-07-01

    A method of analysis of uranium in ores by X-ray spectrometry was developed, using the internal standard technique. Strontium was found to be the most suitable internal standard for general use. A Norelco Philips X-ray fluorescent spectrometer was used in this work, equipped with a lithium fluoride crystal acting as a diffraction grating analyzer. The intensity of the uranium-L {alpha}{sub 1} spectral line is calculated and related to corresponding strontium-K{sub {alpha}} spectral line, both detected with a Scintillation Counter. (Author) 31 refs.

  10. Uranium Determination by Delayed Neutron Counting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Uranium is a very important resource in nuclear industry, especially in the exploiture of nuclear energy. Determination of uranium using delayed neutron counting (DNC) is simple, non-destructive, and

  11. Synchronous derivative fluorimetric determination of boron in Uranium fuel samples

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Poonam, E-mail: poonamv@barc.gov.in [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Shiny S.; Sawant, R.M.; Tomar, B.S. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ramakumar, K.L. [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-09-15

    We report a sensitive and selective method for determination of boron in uranium samples by spectrofluorimetry in synchronous derivative mode. This method is based on the complexation of non-fluorescent boron with fluorescent chromotropic acid to form fluorescent boron–chromotrope complex. The spectrum of native fluorescence of chromotropic acid seriously overlaps with that of the complex and hence, synchronous derivative mode was employed in which physical separation of excess ligand and complex is not necessary. With the optimized experimental and instrumental conditions, limit of detection obtained is 2 ng mL{sup −1}. The linear concentration range is 5–100 ng mL{sup −1} with regression coefficient better than 0.997. The precision is better than 5% at 10 ng mL{sup −1} level and 3% at 50 ng mL{sup −1} level (n=9). Fluorescence quenching by residual matrix elements in the final sample solution is corrected by slope-ratio method. The method is validated with reference materials and successfully applied to the uranium nuclear fuels with the accuracy of ±10%. The proposed method reduces sample size requirement; thereby reducing load of uranium recovery from analytical waste in case of enriched uranium based samples. - Highlights: • Selectivity and sensitivity increases in synchronous derivative mode. • Sample size reduction that reduces load of enriched uranium recovery. • Eliminates need of physical separation of excess ligand and complex. • Quenching by residual matrix elements corrected by the slope-ratio method. • Important contribution to quality control of fuel materials in nuclear technology.

  12. Study of an X-ray fluorescence thin film method for the determination of uranium in low activity solutions; Estudio de un metodo de fluorescencia de rayos X en capa delgada para la determinacion del uranio en soluciones de baja actividad

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Guerra, J. P.

    1980-07-01

    The application of the X-ray fluorescence thin film technique to the uranium determination in nitric solutions for a concentration range from 1 g/l to 100 g/l and activity levels under 5 mCi/ml is studied. The most suited excitation and measurement conditions are also studied and the uranium matrix effect correction, which is performed through the double dilution, {alpha}{sub U}U interaction coefficient calculation and internal standard methods, is discussed. The specimen preparation is satisfactorily accomplished by using P.V.C. filters fixed on aluminium supports. (Author) 18 refs.

  13. Two-Dimensional Fluorescence Spectroscopy for Measuring Uranium Isotopes in Femtosecond Laser Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-05-30

    We present the first two-dimensional fluorescence spectroscopy measurements of uranium isotopes in femtosecond laser ablation plasmas. A new method of signal normalization is presented to reduce noise in absorption-based measurements of laser ablation.

  14. Two-dimensional fluorescence spectroscopy of uranium isotopes in femtosecond laser ablation plumes

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; LaHaye, Nicole L.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-06-19

    We demonstrate measurement of uranium isotopes in femtosecond laser ablation plumes using two-dimensional fluorescence spectroscopy (2DFS). The high-resolution, tunable CW-laser spectroscopy technique clearly distinguishes atomic absorption from 235U and 238U in natural and highly enriched uranium metal samples. We present analysis of spectral resolution and analytical performance of 2DFS as a function of ambient pressure. Simultaneous measurement using time-resolved absorption spectroscopy provides information on temporal dynamics of the laser ablation plume and saturation behavior of fluorescence signals. The rapid, non-contact measurement is promising for in-field, standoff measurements of uranium enrichment for nuclear safety and security applications.

  15. Estimation of Eu3+ in bulk uranium by ligand sensitized fluorescence in dimethyl sulphoxide

    Science.gov (United States)

    Maji, S.; Kumar, Satendra; Sankaran, K.

    2014-12-01

    Ligand sensitized fluorescence of europium ion using thenoyltrifluoroacetone (TTA) as a sensitizing ligand and dimethyl sulphoxide (DMSO) as a solvent is studied for the first time. TTA ligand enhances the fluorescence of Eu3+ by a factor of 40000 in DMSO. Linearity is obtained for a concentration range of 0.076-7.6 ng/mL of Eu3+ with a detection limit of 7.6 pg/mL. The quenching of Eu3+-TTA fluorescence by uranium matrix was studied in different solvents and found to be less in DMSO. Consequently, estimation of Eu3+ in a large excess of uranium becomes a possibility without the need to separate uranium from the solution, which has been demonstrated in this paper. Satisfactory results are obtained when Eu3+ is present at a concentration of 0.6 μg/g in uranium.

  16. Speciation and spectrophotometric determination of uranium in seawater

    Directory of Open Access Journals (Sweden)

    M. KONSTANTINOU

    2012-12-01

    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.

  17. Speciation of bioaccumulated uranium(VI) by Euglena mutabilis cells obtained by laser fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, Sina; Bernhard, Gert [Technical Univ. Dresden (Germany). Radiochemistry; Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany). Inst. of Resource Ecology; Arnold, Thuro [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany). Inst. of Resource Ecology

    2014-07-01

    The ability of Euglena mutabilis cells - a unicellular protozoan with a flexible pellicle, which is typically found in acid mine drainage (AMD) environments - to bioaccumulate uranium under acid conditions was studied in batch sorption experiments at pH 3 and 4 using Na{sub 2}SO{sub 4} and NaClO{sub 4} as background media. It was found that axenic cultures of Euglena mutabilis Schmitz were able to bioaccumulate in 5 days 94.9 to 99.2% of uranium from a 1 x 10{sup -5} mol/L uranium solution in perchlorate medium and 95.1 to 95.9% in sodium sulfate medium, respectively. The speciation of uranium in solution and uranium bioaccumulated by Euglena mutabilis cells, were studied by laser induced fluorescence spectroscopy (LIFS). The LIFS investigations showed that the uranium speciation in the NaClO{sub 4} systems was dominated by free uranyl(VI) species and that the UO{sub 2}SO{sub 4} species was dominating in the Na{sub 2}SO{sub 4} medium. Fluorescence spectra of the bioaccumulated uranium revealed that aqueous uranium binds to carboxylic and/or (organo)phosphate groups located on the euglenid pellicle or inside the Euglena mutabilis cells. Reduced uranium immobilization rates of 0.93-1.43 mg uranium per g Euglena mutabilis biomass were observed in similar experiments, using sterile filtrated AMD waters containing, 4.4 x 10{sup -5} mol/L uranium. These lower rates were attributed to competition with other cations for available sorption sites. Additional LIFS measurements, however, showed that the speciation of the bioaccumulated uranium by the Euglena mutabilis cells was found to be identical with the uranium speciation found in the bioaccumulation experiments carried out in Na{sub 2}SO{sub 4} and NaClO{sub 4} media. The results indicate that Euglena mutabilis has the potential to immobilize aqueous uranium under acid condition and thus may be used in future as promising agent for immobilizing uranium in low pH waste water environments. (orig.)

  18. Concentration Determination of Tetravalent Uranium by Direct Spectrophotometric Method

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The traditional concentration determination method of macro amount of tetravalent uranium in aqueous solution is potassium dichromate titration which is simple to operate with high accuracy and big volume of effluent. In order to simple

  19. Tables for determining lead, uranium, and thorium isotope ages

    Science.gov (United States)

    Schonfeld, E.

    1974-01-01

    Tables for determining lead, uranium, and thorium isotope ages are presented in the form of computer printouts. Decay constants, analytical expressions for the functions evaluated, and the precision of the calculations are briefly discussed.

  20. Determination of uranium and zirconium by flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Alvaro S.F. de; Domingues, Maria de L.F.; Rocha, Valeska P. de Araujo; Jesus, Camila S. de, E-mail: alvaro@ien.gov.br, E-mail: valeska@ien.gov.br, E-mail: luma@ien.gov.br, E-mail: camilasaj@gmail.com [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    As an integral part of chemical quality control of nuclear materials a method for determination of uranium and zirconium, in a mixture is presented. A simple, cheap, selective and quantitative Flow Injection Analysis (FIA) system was developed. Zirconium and uranium were determinate in presence of each other and no prior separation was needed. Arsenazo III was used as a colorimetric reagent and parameters such as acidity and reagents concentration were studied and optimized. An analytical throughput of 30 sample determination per hour was obtained. (author)

  1. Micelle-mediated methodology for the preconcentration of uranium prior to its determination by flow injection

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Laespada, M.E.; Perez Pavon, J.L.; Moreno Cordero, B. (Univ. de Salamanca (Spain). Dept. de Quimica Analitica, Nutricion y Bromatologia)

    1993-02-01

    Cloud point extraction has been used for the preconcentration of uranium, prior to its determination by flow injection. The non-ionic surfactant employed was Triton X-114 and the reagent chosen to form a hydrophobic chelate of uranium was 1-(2-pyridylazo)-2-naphthol. The optimum conditions for the preconcentration and determination of uranium have been studied. This methodology has been applied to the determination of trace amounts of uranium in tap and river waters from Salamanca. (Author).

  2. Determination of Uranium and Plutonium Concentration in 1AF by Isotopic Dilution Mass Spectrometry Methods

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>It is important data to measure uranium and plutonium concentration for the reprocessing plant control analysis. The determination of uranium and plutonium concentration in 1AF by isotopic dilution mass

  3. Accurate and Precise Determination of Uranium by Means of Extraction Spectrophotometric

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Uranium is an important nuclear material. Accurate determination of uranium is significant in the nuclear fuel production, accountancy, nuclear safeguards and other procedures of nuclear fuel cycle.

  4. Evaluation of kinetic phosphorescence analysis for the determination of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Croatto, P.V.; Frank, I.W.; Johnson, K.D.; Mason, P.B.; Smith, M.M.

    1997-12-01

    In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11 offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO{sub 3} before measurement. Concentrations were determined on a mass basis ({micro}g U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same

  5. Procedure for Uranium-Molybdenum Density Measurements and Porosity Determination

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Ramprashad [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Devaraj, Arun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-13

    The purpose of this document is to provide guidelines for preparing uranium-molybdenum (U-Mo) specimens, performing density measurements, and computing sample porosity. Typical specimens (solids) will be sheared to small rectangular foils, disks, or pieces of metal. A mass balance, solid density determination kit, and a liquid of known density will be used to determine the density of U-Mo specimens using the Archimedes principle. A standard test weight of known density would be used to verify proper operation of the system. By measuring the density of a U-Mo sample, it is possible to determine its porosity.

  6. Fluorimetric determination of uranium in water; Determinacion fluorimetrica de uranio en aguas

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-02-15

    The fluorimetric method for the determination of microquantities of uranium in water is described. This method covers the determination of uranium in water in the interval from 0.2 to 50 ppm on 50 ml. of radioactive base sample. These limits can be variable if the volume of the aliquot one of the base sample is changed, as well as the volume of the used aliquot one for to the final determination of uranium. (Author)

  7. Determination of irradiated reactor uranium in soil samples in Belarus using 236U as irradiated uranium tracer.

    Science.gov (United States)

    Mironov, Vladislav P; Matusevich, Janna L; Kudrjashov, Vladimir P; Boulyga, Sergei F; Becker, J Sabine

    2002-12-01

    This work presents experimental results on the distribution of irradiated reactor uranium from fallout after the accident at Chernobyl Nuclear Power Plant (NPP) in comparison to natural uranium distribution in different soil types. Oxidation processes and vertical migration of irradiated uranium in soils typical of the 30 km relocation area around Chernobyl NPP were studied using 236U as the tracer for irradiated reactor uranium and inductively coupled plasma mass spectrometry as the analytical method for uranium isotope ratio measurements. Measurements of natural uranium yielded significant variations of its concentration in upper soil layers from 2 x 10(-7) g g(-1) to 3.4 x 10(-6) g g(-1). Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 5 x 10(-12) g g(-1) to 2 x 10(-6) g g(-1) depending on the distance from Chernobyl NPP. In the majority of investigated soil profiles 78% to 97% of irradiated "Chernobyl" uranium is still contained in the upper 0-10 cm soil layers. The physical and chemical characteristics of the soil do not have any significant influence on processes of fuel particle destruction. Results obtained using carbonate leaching of 236U confirmed that more than 60% of irradiated "Chernobyl" uranium is still in a tetravalent form, ie. it is included in the fuel matrix (non-oxidized fuel UO2). The average value of the destruction rate of fuel particles determined for the Western radioactive trace (k = 0.030 +/- 0.005 yr(-1)) and for the Northern radioactive trace (k = 0.035 + 0.009 yr(-1)) coincide within experimental errors. Use of leaching of fission products in comparison to leaching of uranium for study of the destruction rate of fuel particles yielded poor coincidence due to the fact that use of fission products does not take into account differences in the chemical properties of fission products and fuel matrix (uranium).

  8. Standard test method for analysis of uranium and thorium in soils by energy dispersive X-Ray fluorescence spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers the energy dispersive X-ray fluorescence (EDXRF) spectrochemical analysis of trace levels of uranium and thorium in soils. Any sample matrix that differs from the general ground soil composition used for calibration (that is, fertilizer or a sample of mostly rock) would have to be calibrated separately to determine the effect of the different matrix composition. 1.2 The analysis is performed after an initial drying and grinding of the sample, and the results are reported on a dry basis. The sample preparation technique used incorporates into the sample any rocks and organic material present in the soil. This test method of sample preparation differs from other techniques that involve tumbling and sieving the sample. 1.3 Linear calibration is performed over a concentration range from 20 to 1000 μg per gram for uranium and thorium. 1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units in parentheses are for information only. 1.5 This standard...

  9. Laser-induced breakdown spectroscopy for determination of uranium in thorium-uranium mixed oxide fuel materials.

    Science.gov (United States)

    Sarkar, Arnab; Alamelu, Devanathan; Aggarwal, Suresh K

    2009-05-15

    Laser-induced breakdown spectroscopy (LIBS) has been developed for determining the percentage of uranium in thorium-uranium mixed oxide fuel samples required as a part of the chemical quality assurance of fuel materials. The experimental parameters were optimized using mixed oxide pellets prepared from 1:1 (w/w) mixture of thorium-uranium mixed oxide standards and using boric acid as a binder. Calibration curves were established using U(II) 263.553 nm, U(II) 367.007 nm, U(II) 447.233 nm and U(II) 454.363 nm emission lines. The uranium amount determined in two synthetic mixed oxide samples using calibration curves agreed well with that of the expected values. Except for U(II) 263.553 nm, all the other emission lines exhibited a saturation effect due to self-absorption when U amount exceeded 20 wt.% in the Th-U mixture. The present method will be useful for fast and routine determination of uranium in mixed oxide samples of Th and U, without the need for dissolution, which is difficult and time consuming due to the refractory nature of ThO(2). The methodology developed is encouraging since a very good analytical agreement was obtained considering the limited resolution of the spectrometer employed in the work.

  10. Characterization of uranium bearing material using x-ray fluorescence and direct gamma-rays measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mujaini, M., E-mail: madihah@uniten.edu.my; Chankow, N. [Faculty of Engineering, Chulalongkorn University Phyathai Rd., Wang Mai, Patumwan, Bangkok 10330 (Thailand); Yusoff, M. Z.; Hamid, N. A. [College of Engineering, Universiti Tenaga Nasional 43000 Kajang, Selangor (Malaysia)

    2016-01-22

    Uranium ore can be easily detected due to various gamma-ray energies emitted from uranium daughters particularly from {sup 238}U daughters such as {sup 214}Bi, {sup 214}Pb and {sup 226}Ra. After uranium is extracted from uranium ore, only low energy gamma-rays emitted from {sup 235}U may be detected if the detector is placed in close contact to the specimen. In this research, identification and characterization of uranium bearing materials is experimentally investigated using direct measurement of gamma-rays from {sup 235}U in combination with the x-ray fluorescence (XRF) technique. Measurement of gamma-rays can be conducted by using high purity germanium (HPGe) detector or cadmium telluride (CdTe) detector while a {sup 57}Coradioisotope-excited XRF spectrometer using CdTe detector is used for elemental analysis. The proposed technique was tested with various uranium bearing specimens containing natural, depleted and enriched uranium in both metallic and powder forms.

  11. Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media.

    Science.gov (United States)

    Popov, L

    2016-09-01

    Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials.

  12. Uranium in surface soils: an easy-and-quick assay combining X-ray diffraction and fluorescence qualitative data

    Science.gov (United States)

    Figueiredo, M. O.; Silva, T. P.; Batista, M. J.; Leote, J.; Ferreira, M. L.; Limpo, V.

    2009-04-01

    Portugal has been a uranium-producer since the beginning of the last century. The uranium-rich area of Alto Alentejo, East-central Portugal, was identified more than fifty years ago [1]. Almost all the uranium-bearing mineralization occurs in schistose rocks of the contact metamorphic aureole produced by intrusion of the Hercynian monzonitic granite of Alto Alentejo into the pre-Ordovitian schist-greywacke complex forming deposits of vein and dissemination type. The Nisa uranium-reservoir, situated at the sharp border of a large and arch shaped granite pluton, was identified in 1957 [2] but its exploitation was considered economically impracticable until recently. However, its existence and the accumulated detritus of these prospect efforts are a concern for local populations [3]. A study of the near-surface soils close to the Nisa reservoir was therefore undertaken to assess the uranium retention by adsorption on clay components under the form of uranyl ions, [UO2]2+ [4-6] and its eventual release into the aquifer groundwater. As an attempt to very quickly appraise the presence of uranium in as-collected near-surface sediment samples a combination of laboratory X-ray techniques was designed: X-ray diffraction (XRD) to identify the mineral phases and roughly estimate its relative proportion plus X-ray fluorescence spectrometry in wavelength dispersive mode (XRF-WDS) to ascertain the presence of uranium and tentatively evaluate its content by comparison with selected chemical components of the soil. A description of the experimental methodology adopted for the implemented easy-and-quick uranium assay is presented. Obtained results compare quite well to the data of certified time-consuming analytical tests of uranium in those soil samples. [1] L. Pilar (1966) Conditions of formation of Nisa uranium deposit (in Portuguese). Comunic. Serv. Geol. Portugal, tomo L, 50-85. [2] C. Gonçalves & J.V. Teixeira Lopes (1971) Uranium deposit of Nisa: geological aspects of its

  13. Uranium(VI) coordination polymers with pyromellitate ligand: Unique 1D channel structures and diverse fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingjie, E-mail: yzx@ansto.gov.au [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Bhadbhade, Mohan [Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052 (Australia); Karatchevtseva, Inna [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Price, Jason R. [Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168 (Australia); Liu, Hao [Centre for Clean Energy Technology, School of Chemistry and Forensic Science, University of Technology Sydney, PO Box 123, Broadway, Sydney, NSW 2007 (Australia); Zhang, Zhaoming; Kong, Linggen [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Čejka, Jiří [Department of Mineralogy, National Museum, Václavské náměstí, 68, Prague 1, 115 79-CZ (Czech Republic); Lu, Kim; Lumpkin, Gregory R. [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2015-03-15

    Three new coordination polymers of uranium(VI) with pyromellitic acid (H{sub 4}btca) have been synthesized and structurally characterized. (ED)[(UO{sub 2})(btca)]·(DMSO)·3H{sub 2}O (1) (ED=ethylenediammonium; DMSO=dimethylsulfoxide) has a lamellar structure with intercalation of ED and DMSO. (NH{sub 4}){sub 2}[(UO{sub 2}){sub 6}O{sub 2}(OH){sub 6}(btca)]·~6H{sub 2}O (2) has a 3D framework built from 7-fold coordinated uranyl trinuclear units and btca ligands with 1D diamond-shaped channels (~8.5 Å×~8.6 Å). [(UO{sub 2}){sub 2}(H{sub 2}O)(btca)]·4H{sub 2}O (3) has a 3D network constructed by two types of 7-fold coordinated uranium polyhedron. The unique μ{sub 5}-coordination mode of btca in 3 enables the formation of 1D olive-shaped large channels (~4.5 Å×~19 Å). Vibrational modes, thermal stabilities and fluorescence properties have been investigated. - Graphical abstract: Table of content: three new uranium(VI) coordination polymers with pyromellitic acid (H{sub 4}btca) have been synthesized via room temperature and hydrothermal synthesis methods, and structurally characterized. Two to three dimensional (3D) frameworks are revealed. All 3D frameworks have unique 1D large channels. Their vibrational modes, thermal stabilities and photoluminescence properties have been investigated. - Highlights: • Three new coordination polymers of U(VI) with pyromellitic acid (H{sub 4}btca). • Structures from a 2D layer to 3D frameworks with unique 1D channels. • Unusual µ{sub 5}-(η{sub 1}:η{sub 2}:η{sub 1}:η{sub 2:}η{sub 1}) coordination mode of btca ligand. • Vibrational modes, thermal stabilities and luminescent properties reported.

  14. Determination of Uranium in Apatite Minerals by Solvent Extraction--Inductively Coupled Plasma Atomic Emission Spectrometry

    OpenAIRE

    1993-01-01

    [Abstract] Solvent, extraction-ICP atomic emission spectrometry was applied to the determination of uranium in apatite minerals. Apatite minerals were treated with nitric acid. After removing a small quantity of insoluble residue, uranium was extracted with 0.05 mol/dm^3 1-phonyl-3-mcthyl-4-trifluoroacetyl-5-pyrazolonc-diisobutyl kctone at pH 0.8. The uranium content in the apatite was found to be (20.3〜132.9)×10^%.

  15. NGSI FY15 Final Report. Innovative Sample Preparation for in-Field Uranium Isotopic Determinations

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Thomas M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Meyers, Lisa [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-10

    Our FY14 Final Report included an introduction to the project, background, literature search of uranium dissolution methods, assessment of commercial off the shelf (COTS) automated sample preparation systems, as well as data and results for dissolution of bulk quantities of uranium oxides, and dissolution of uranium oxides from swipe filter materials using ammonium bifluoride (ABF). Also, discussed were reaction studies of solid ABF with uranium oxide that provided a basis for determining the ABF/uranium oxide dissolution mechanism. This report details the final experiments for optimizing dissolution of U3O8 and UO2 using ABF and steps leading to development of a Standard Operating Procedure (SOP) for dissolution of uranium oxides on swipe filters.

  16. Uranium determination in the red blood cells of workers engaged in the chemical treatment of uranium ore

    Energy Technology Data Exchange (ETDEWEB)

    Nosek, J.; Simkova, M.; Kukula, F.; Musil, K.

    1973-10-01

    Using the neutron activation analysis method, the uranium levels were determined in red blood cells of venous blood samples from persons occupationally exposed to this metal in chemical processing plants using wet methods (6.5+-2.1ppb U) or dry methods (37.2+-20.2ppb U), and of controls (4.1+-2.6ppb U).

  17. Standard test method for uranium analysis in natural and waste water by X-ray fluorescence

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method applies for the determination of trace uranium content in waste water. It covers concentrations of U between 0.05 mg/L and 2 mg/L. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  18. Spectrophotometric simultaneous determination of uranium and thorium using partial least squares regression and orthogonal signal correction

    Energy Technology Data Exchange (ETDEWEB)

    Niazi, Ali [Azad University of Arak (Iran, Islamic Republic of). Faculty of Sciences. Dept. of Chemistry]. E-mail: ali.niazi@gmail.com

    2006-09-15

    A simple, novel and sensitive spectrophotometric method was described for simultaneous determination of uranium and thorium. The method is based on the complex formation of uranium and thorium with Arsenazo III at pH 3.0. All factors affecting the sensitivity were optimized and the linear dynamic range for determination of uranium and thorium found. The simultaneous determination of uranium and thorium mixtures by using spectrophotometric methods is a difficult problem, due to spectral interferences. By multivariate calibration methods such as partial least squares (PLS), it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 600-760 nm range for 25 different mixtures of uranium and thorium. Calibration matrices contained 0.10- 21.00 and 0.25-18.50 {mu}g mL{sup -1} of uranium and thorium, respectively. The RMSEP for uranium and thorium with OSC and without OSC were 0.4362, 0.4183 and 1.5710, 1.0775, respectively. This procedure allows the simultaneous determination of uranium and thorium in synthetic and real matrix samples with good reliability of the determination. (author)

  19. Determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Le Cong; Tao, Chau Van; Thong, Luong Van; Linh, Duong Mong [University of Science Ho Chi Minh City (Viet Nam). Faculty of Physics and Engineering Physics; Dong, Nguyen Van [University of Science Ho Chi Minh City (Viet Nam). Faculty of Chemistry

    2011-08-15

    In this study, a simple procedure for the determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy is described. This procedure allows a sequential extraction polonium, uranium, thorium and radium radionuclides from the same sample in two to three days. It was tested and validated with the analysis of certified reference materials from the IAEA. (orig.)

  20. Uranium isotopes quantitatively determined by modified method of atomic absorption spectrophotometry

    Science.gov (United States)

    Lee, G. H.

    1967-01-01

    Hollow-cathode discharge tubes determine the quantities of uranium isotopes in a sample by using atomic absorption spectrophotometry. Dissociation of the uranium atoms allows a large number of ground state atoms to be produced, absorbing the incident radiation that is different for the two major isotopes.

  1. Correction for the interference of strontium in the determination of uranium in geologic samples by X-ray fluorescence; Correccion de la interferencia del estroncio en la determinacion del uranio en materiales geologicos mediante fluorescencia de rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M.; Bayon, A.

    1981-07-01

    A suitable empirical algorithm for the correction for the spectral interference of the SrK{alpha} on the UL{alpha} line has been derived. It works successfully for SrO concentrations up to 8% with a minimum detectable limit of 20 ppm U{sub 3}O{sub 8}. X-ray spectrometry procedure allows also the determination of the SrO contents of the samples. A program in BASIC language for data reduction has been written. (Author) 3 refs.

  2. Determination of solubility of uranium in liquid sodium

    Institute of Scientific and Technical Information of China (English)

    YANG Tongzai; XING Pifeng; YE Shiyou; LONG Kaiming; FU Zhonghua; HE Yuhui; JIANG Tao

    2008-01-01

    An experimental technique has been developed which overcomes the two major problems common to liquid metal solubility measurements, namely, maintaining the integrity of the samples during transfer of the liquid sodium from container to whatever device is used for analysis and detecting solute at very low concentration in liquid sodium. The solubility of uranium in liquid sodium has been measured over the temperature range 150~400℃, by equilibration and sampling technique, the solubility of uranium is approximately 0.00001%.

  3. Monochromatic wavelength dispersive x-ray fluorescence providing sensitive and selective detection of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George J [Los Alamos National Laboratory; Collins, Michael L [Los Alamos National Laboratory; Montoya, Velma M [Los Alamos National Laboratory; Chen, Zewu [XOS; Wei, Fuzhong [XOS

    2010-01-01

    Monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) is a sensitive and selective method for elemental compositional analyses. The basis for this instrumental advance is the doubly curved crystal (DCC) optic. Previous work has demonstrated the feasibility of sensitive trace element detection for yttrium as a surrogate for curium in aqueous solutions. Additional measurements have demonstrated similar sensitivity in several different matrix environments which attests to the selectivity of the DCC optic as well as the capabilities of the MWDXRF concept. The objective of this effort is to develop an improved Pu characterization method for nuclear fuel reprocessing plants. The MWDXRF prototype instrument is the second step in a multi-year effort to achieve an improved Pu assay. This work will describe a prototype MWDXRF instrument designed for uranium detection and characterization. The prototype consists of an X-ray tube with a rhodium anode and a DCC excitation optic incorporated into the source. The DCC optic passes the RhK{alpha} line at 20.214 keV for monochromatic excitation of the sample. The source is capable of 50 W power at 50 kV and 1.0 mA operation. The x-ray emission from the sample is collected by a DCC optic set at the UL{alpha} line of 13.613 keV. The collection optic transmits the UL{alpha} x-rays to the silicon drift detector. The x-ray source, sample, collection optic and detector are all mounted on motion controlled stages for the critical alignment of these components. The sensitivity and selectivity of the instrument is obtained through the monochromatic excitation and the monochromatic detection. The prototype instrument performance has a demonstrated for sensitivity for uranium detection of around 2 ppm at the current state of development. Further improvement in sensitivity is expected with more detailed alignment.

  4. Determination of thorium and uranium contents in soil samples using SSNTD's passive method

    Indian Academy of Sciences (India)

    T A Salama; U Seddik; T M Dsoky; A Ahmed Morsy; R El-Asser

    2006-08-01

    Thorium-to-uranium ratios have been determined in different soil samples using CR-39 and LR-115-II solid-state nuclear track detectors (SSNTDs). A calibration method based on determination of SSNTD registration sensitivity ratio for -particles of thorium and uranium series has been developed. Thorium and uranium contents of the standard soil samples have been determined and compared with its known values. There is a good agreement between the results of this method and the values of standard samples. The method is simple, inexpensive, non-destructive and has a wide range of applications in environment, building materials and petroleum fields.

  5. Determination of uranium fission product interference factor for molybdenum quantification by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Junior, Ibere S.; Saiki, Mitiko; Genezini, Frederico A.; Zahn, Guilherme S., E-mail: ibere@usp.br, E-mail: mitiko@ipen.br, E-mail: fredzini@ipen.br, E-mail: gzahn@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Instrumental Neutron Activation Analysis (INAA) is a technique that provides high precision and accuracy results for the concentration determinations of several elements in different kinds of matrices. However, if the sample contains high uranium concentration in their composition, INAA can provide inaccurate results due to uranium fission product interferences. The molybdenum is one of these elements that suffers interference by uranium fission product, because the {sup 99}Mo radioisotope formed by {sup 98}Mo neutron capture, used in INAA, is the same that formed in the uranium fission. This kind of interference can be solved by separation of uranium before irradiation or by determining the uranium interference factor to the radioisotope of interest and applying the correction. The present study aims at the following: (1) determination of the Mo interference factor (F{sub Exp}{sup Mo}) due to the uranium fission product {sup 99}Mo by irradiating standards of Mo and U with known masses of these elements (experimental interference factor); (2) determination of the theoretical F{sub Th}{sup Mo}, in this case it was necessary to determine the epithermal to thermal neutron flux ratio and use the reported nuclear parameters; (3) comparison of the results of the interference factor obtained with values reported in the literature. The interference factor for Mo analysis was obtained in a position 14b shelf 3 of the IEA-R1 nuclear research reactor. (author)

  6. Uranium and plutonium solution assays by transmission-corrected x-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Ryon, R W; Ruhter, W D; Rudenko, V; Sirontinin, A; Petrov, A A

    1999-09-08

    We have refined and tested a previously developed x-ray fluorescence analysis technique for uranium and plutonium solutions that compensates for variations in the absorption of the exciting gamma rays and fluorescent x-rays. We use {sup 57}Co to efficiently excite the K lines of the elements, and a mixed {sup 57}Co plus {sup 153}Gd transmission source to correct for variations in absorption. The absorption correction is a unique feature of our technique. It is possible to accurately calibrate the system with a single solution standard. There does not need to be a close match in composition (i.e., absorption) between the standard(s) and solutions to be analyzed. Specially designed equipment incorporates a planar intrinsic germanium detector, excitation and transmission radioisotopes, and specimen holder. The apparatus can be inserted into a rubber glove of a glovebox, keeping the apparatus outside and the solutions inside the glovebox, thereby protecting the user and the equipment from possible contamination. An alternate design may be used in chemical reprocessing plants, providing continuous monitoring, by measuring the trans-actinides through stainless steel piping. This technique has been tested at the Bochvar Research Institute of Inorganic Materials in Moscow for possible use in the Russian complex of nuclear facilities. This is part of a cooperative program between laboratories in the United States and Russia to strengthen systems of nuclear materials protection, control, and accountability (MPC and A). A part of this program is to accurately measure and track inventories of materials, thus the need for good non-destructive analytical techniques such as the one described here.

  7. Direct determination of uranium and co-extracted elements in the organic phases (D2EHPA/TOPO, TBP, TDA) in kerosene by TXRF technique.

    Science.gov (United States)

    Stas, J; Khuder, A; Karjou, J

    2008-04-01

    The total reflection X-ray fluorescence (TXRF) spectrometry was used for direct determination of uranium concentration in the organic phase di-(2-ethyl hexyl) phosphoric acid and trioctyl phosphine oxide (D(2)EHPA-TOPO)/kerosene, which resulted from first and second cycles of uranium extraction from wet-process phosphoric acid. The TXRF measurements were performed using gallium as an internal standard. A linear relationship between relative intensity of uranium vs. gallium (I(U)/S(Ga)) against uranium concentration has been obtained. Four calibration curves, 0-5, 5-100, 100-1000 and 1000-7000 microgmL(-1), according to uranium concentration in the studied samples, were constructed. The detection limit was found to be 0.15 microgmL(-1). The effect of D(2)EHPA and TOPO concentration in kerosene on uranium determination was considered. The TXRF spectrometry was also applied for the multi-elemental analysis of the co-extracted impurities with uranium, such as (Fe, Ni, Cu and Zn) in the organic phase, and four calibration curves, 0-500 microgmL(-1) Fe, 0-20 microgmL(-1) Ni, 0-10 microgmL(-1) Cu and 0-20 microgmL(-1) Zn, according to Fe, Ni, Cu and Zn concentration in the studied samples were performed, respectively, using gallium as an internal standard. The obtained results using direct TXRF analysis method were in a very good agreement with those obtained by fluorometry method, which is suitable for aqueous solutions after stripping of uranium from the organic phase by 1M Na(2)CO(3).

  8. Feasibility of using fluorescence in situ hybridization (FISH) to detect early gene changes in sputum cells from uranium miners

    Energy Technology Data Exchange (ETDEWEB)

    Neft, R.E.; Rogers, J.L.; Belinsky, S.A. [and others

    1995-12-01

    Epidemiological studies have shown that combined exposure to radon progeny and tobacco smoke produce a greater than additive or synergistic increase in lung cancer risk. Lung cancer results from multiple genetic changes over a long period of time. An early change that occurs in lung cancer is trisomy 7 which is found in 50% of non-small cell lung cancer and in the far margins of resected lung tumors. The 80% mortality associated with lung cancer is in part related to the high proportion of patients who present with an advanced, unresectable tumor. Therefore, early detection of patients at risk for tumor development is critical to improve treatment of this disease. Currently, it is difficult to detect lung cancer early while it is still amendable by surgery. Saccomanno, G. has shown that premalignant cytologic changes in sputum cells collected from uranium miners can be detected by a skilled, highly trained cytopathologist. A more objective alternative for identifying premalignant cells in sputum may be to determine whether an early genetic change such as trisomy 7 is present in these cells. Fluorescence in situ hybridization (FISH) can be used to identify cells with trisomy 7. The results of this investigation indicate that FISH may prove to be an accurate, efficient method to test at-risk individuals for genetic alterations in bronchial epithelial cells from sputum.

  9. 高矿化度水样中微量铀的测定%Trace Uranium Determination in High Salinity Brine

    Institute of Scientific and Technical Information of China (English)

    白静; 赵梁; 范芳丽; 吴晓蕾; 丁华杰; 雷富安; 田伟; 秦芝; 郭俊盛

    2011-01-01

    With the development of nuclear power industry in our country, the needs for uranium will increase drastically. But as the uranium resource in uranium mines are very limited, much attention has been paid on the uranium recovery from other resources, such as sea water and high salinity brine. Accurate determination of uranium concentration is very important, if uranium recovery was performed on this complicate water. Trace uranium determination in high salinity brine, for instance, salt lake and intercrystalline bittern samples, was studied in present work by using ultraviolet fluorescence method. As the instrument is stable, the optimal conditions for uranium determination are found to be: pH = 2-12, added fluorescence-enhancing agent amount of 500 μL; to reduce the negative effect of impurity ions on uranium determination, both direct dilution and TBP extraction fluorescence methods are investigated. The procedure used for TBP extraction fluorescence method is confirmed by employing different solvents as TBP diluent, and the uranium recov-ery rate is determined to be 85%. Under the optimal conditions, both methods mentioned above were used for analyzing uranium concentration in salt lake and intercrystalline bittern samples. The obtained results were compared with those measured by inductively coupled plasma mass spectrometry (ICP-MS) method. Good consistency among the results is founded, which clearly shows that the method can be used for uranium determination in high salinity brine.%通过系统对比实验,建立了一种适合于盐湖水、晶间卤水等高矿化度液体样品中微量铀的测定方法——紫外荧光法.在确定仪器测量稳定性的基础上,给出紫外荧光法测定铀的最佳条件为样品pH=2~12,荧光增强剂用量为500μL.为减少杂质离子对铀测定的干扰,分别采用直接稀释荧光法及TBP萃取荧光法进行铀的测定,确定了TBP萃取荧光法测量高矿化度水样中微量铀的步

  10. Trace determination of uranium in fertilizer samples by total reflection X-ray fluorescence

    Indian Academy of Sciences (India)

    N L Misra; Sangita Dhara; Arijeet Das; G S Lodha; S K Aggarwal; I Varga

    2011-02-01

    Uranium is reported to be present in phosphate fertilizers. The recovery of uranium from the fertilizers is important because it can be used as fuel in nuclear reactors and also because of environmental concerns. For both these activities suitable method of uranium determinations at trace levels in these fertilizers are required. Studies have been initiated for such TXRF determination of uranium and the results are reported in the present paper. For TXRF determinations the fertilizer samples were processed with nitric acid and the uranium present in it was removed by solvent extraction using tri-n-butyl phosphate as the extractant. The organic phase containing uranium was equilibrated with 1.5% suprapure nitric acid to bring out uranium in aqueous phase. This aqueous phase was mixed with internal standard Y and the TXRF spectra were measured by depositing samples on float glass supports. The amounts of uranium in four fertilizer samples of Hungarian origin were determined by processing these TXRF spectra. Uranium concentrations in two fertilizer samples were found to be in the range of 4–6 /, whereas two fertilizer samples did not show the presence of uranium. The precision of the TXRF determination of uranium was found to be better than 8 % (1).

  11. Determination of natural and depleted uranium in urine at the ppt level: an interlaboratory analytical exercise

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostino, P.A. [Defence R and D Canada - Suffield, Medicine Hat, Alberta (Canada); Ough, E.A. [Royal Military College of Canada, Kingston, Ontario (Canada); Glover, S.E. [Los Alamos National Lab., Los Alamos, NM (United States); Vallerand, A.L.

    2002-10-15

    An analytical exercise was initiated in order to determine those analytical procedures with the capacity to measure uranium isotope ratios ({sup 238}U/{sup 235}U) in urine samples containing less that 1{mu} uranium /L urine. A host laboratory was tasked with the preparation of six sets (12 samples per set) of synthetic urine samples spiked with varying amounts of natural and depleted (0.2% {sup 235}U) uranium. The sets of samples contained total uranium in the range 25 ng U/L urine to 770 ng U/L urine, with isotope ratios ({sup 238}U/{sup 235}U) from 137.9 (natural uranium) to 215 ({approx}50% depleted uranium). Sets of samples were shipped to five testing laboratories (four Canadian and one European) for total and isotopic assay. The techniques employed in the analyses included sector field inductively coupled plasma mass spectrometry (ICP-SF-MS), quadrupole inductively coupled plasma mass spectrometry (ICP-Q-MS), thermal ionization mass spectrometry (TIMS) and neutron activation analysis (NAA). Full results were obtained from three testing labs (ICP-SF-MS, ICP-Q-MS and TIMS). Their results, plus partial results from the NAA lab, have been included in this report. Total uranium and isotope ratio results obtained from ICP-SF-MS and ICP-Q-MS were in good agreement with the host lab values. Neutron activation analysis and TIMS reported total uranium concentrations that differed from the host lab. An incomplete set of isotopic ratios was obtained from the NAA lab with some results reporting enriched uranium (%{sup 235}U > 0.7). Based on the reported results, the four analytical procedures were ranked: ICP-SF-MS (1), ICP-Q-MS (2), TIMS (3) and NAA (4). (author)

  12. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  13. Fluorimetric determination of uranium in zirconium and zircaloy alloys; Determinacion fluorimetrica de uranio en aleaciones de zirconio y zircaloy

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-05-15

    The objective of this procedure is to determine microquantities of uranium in zirconium and zircaloy alloys. The report also covers the determination of uranium in zirconium alloys and zircaloy in the range from 0.25 to 20 ppm on 1 g of base sample of radioactive material. These limit its can be variable if the size of the used aliquot one is changed for the final determination of uranium. (Author)

  14. Uranium isotopes determination in urine samples using alpha spectrometry and ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Mychelle M.L.; Maihara, Vera A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Tine, Fernanda D.; Santos, Sandra M.C.; Bonifacio, Rodrigo L.; Taddei, Maria HelenaT. [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas

    2015-07-01

    The action of determining the concentration of uranium isotopes in biological samples, 'in vitro' bioassay, is an indirect method for evaluating the incorporation and quantification of these radionuclides internally deposited. When incorporated, these radionuclides tend to be disposed through excretion, with urine being the main source of data because it can be easily collected and analyzed. The most widely used methods for determination of uranium isotopes ({sup 234}U, {sup 235}U and {sup 238}U) are Alpha Spectrometry and ICP-MS. This work presents a comparative study for the determination of uranium isotopes using these two methodologies in real samples from occupationally exposed workers. In order to validate the methodology, a sample of the intercomparison exercise organized by PROCORAD (Association pour la Promotion du Controle de Qualite des Analyses de Biologie Medicale em Radiotoxicologie) was used, and the results were statistically compared applying the Student's t-test. (author)

  15. A simple method for the absolute determination of uranium enrichment by high-resolution {gamma} spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Korob, R.O. [Unidad de Actividad Radioquimica y Quimica de las Radiaciones, Comision Nacional de Energia Atomica, Centro Atomico Ezeiza, Presbitero Juan Gonzalez y Aragon No. 15 Partido de Ezeiza, Provincia de Buenos Aires (Argentina)]. E-mail: korob@cae.cnea.gov.ar; Blasiyh Nuno, G.A. [Unidad de Actividad Gestion de Residuos Radiactivos, Comision Nacional de Energia Atomica, Centro Atomico Ezeiza, Presbitero Juan Gonzalez y Aragon No. 15 Partido de Ezeiza, Provincia de Buenos Aires (Argentina)

    2006-05-15

    A simple method for the determination of uranium enrichment using high-resolution {gamma} spectrometry is presented in this paper. The method relies solely on the {gamma}-ray emission probabilities of {sup 235}U and {sup 234m}Pa, and an iterative procedure for the least squares fit of a polynomial to a set of experimentally determined data. To ensure the reliability of the {sup 234m}Pa {gamma}-ray emission probabilities employed, a new determination of these probabilities was carried out using a combination of {gamma} spectrometry and Cerenkov counting of a purified {sup 234}Th solution. Using these new data, a maximum difference of {approx}5% has been found between the experimental and declared uranium enrichment in a set of solid and liquid samples containing uranium compounds.

  16. A neutron activation analysis procedure for the determination of uranium, thorium and potassium in geologic samples

    Science.gov (United States)

    Aruscavage, P. J.; Millard, H.T.

    1972-01-01

    A neutron activation analysis procedure was developed for the determination of uranium, thorium and potassium in basic and ultrabasic rocks. The three elements are determined in the same 0.5-g sample following a 30-min irradiation in a thermal neutron flux of 2??1012 n??cm-2??sec-1. Following radiochemical separation, the nuclides239U (T=23.5 m),233Th (T=22.2 m) and42K (T=12.36 h) are measured by ??-counting. A computer program is used to resolve the decay curves which are complex owing to contamination and the growth of daughter activities. The method was used to determine uranium, throium and potassium in the U. S. Geological Survey standard rocks DTS-1, PCC-1 and BCR-1. For 0.5-g samples the limits of detection for uranium, throium and potassium are 0.7, 1.0 and 10 ppb, respectively. ?? 1972 Akade??miai Kiado??.

  17. DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRY FOR DETERMINATION OF SOME HEAVY METALS IN URANIUM

    Directory of Open Access Journals (Sweden)

    Saryati Saryati

    2010-06-01

    Full Text Available The direct determination of some metals impurity in uranium by using differential pulse anodic stripping voltammetry (DPASV method at a hanging mercury drop electrode and in a carbonate buffer media was developed. It was found that the carbonate buffer show the strongest affinity for uranium and gives the best separation between the DPASV peaks of heavy metals impurities. The carbonate concentration markedly affects the oxidation and reduction the major and the minor constituents of the uranium samples. In 0.1 M carbonate buffer solution pH 10, copper, bismuth, thalium, lead, cadmium, zinc, could be determined without the removal of the uranium matrix. Recovery and relative standard deviation (RSD of this method was in the range of 174% - 85.2% for recovery and 36.8% - 1.2% for RSD. The larger error of analytical result was obtained for Zn at low concentration. In general, the analytic results error and RSD decreased with increasing metals concentration.   Keywords: heavy metal determination, differential pulse anodic stripping voltammetry, uranium

  18. DETERMINATION OF AMINOGLYCOSIDES IN FOOD BY FLUORESCENCE POLARIZATION IMMUNOASSAY

    OpenAIRE

    FARAFONOVA O.V.; Eremin, S. A.; ERMOLAEVA T.N.; VASILIEV S.V.

    2015-01-01

    The methodic for quantitative determination of aminoglycoside antibiotics (gentamicin, kanamycin, streptomycin, amikacin, neomycin) in food by polarization fluorescent immunoassay (FPIA) is developed. The size and structure influence of a fluorescent molecule on a fluorescence polarization degree is analyzed. Affinity constants of antibodies to compounds and tracers were estimated, optimized working concentration of tracers and antibodies that provide the maximum value of analytical signal. M...

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

    Directory of Open Access Journals (Sweden)

    ChandraSekhar Reddy Gadikota

    2011-08-01

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

  20. Determining uranium speciation in contaminated soils by molecular spectroscopic methods: Examples from the Uranium in Soils Integrated Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Allen, P.G.; Berg, J.M.; Chisholm-Brause, C.J.; Conradson, S.D.; Donohoe, R.J.; Morris, D.E.; Musgrave, J.A.; Tait, C.D.

    1994-03-01

    The US Department of Energy`s former uranium production facility located at Fernald, OH (18 mi NW of Cincinnati) is the host site for an Integrated Demonstration for remediation of uranium-contaminated soils. A wide variety of source terms for uranium contamination have been identified reflecting the diversity of operations at the facility. Most of the uranium contamination is contained in the top {approximately}1/2 m of soil, but uranium has been found in perched waters indicating substantial migration. In support of the development of remediation technologies and risk assessment, we are conducting uranium speciation studies on untreated and treated soils using molecular spectroscopies. Untreated soils from five discrete sites have been analyzed. We have found that {approximately}80--90% of the uranium exists as hexavalent UO{sub 2}{sup 2+} species even though many source terms consisted of tetravalent uranium species such as UO{sub 2}. Much of the uranium exists as microcrystalline precipitates (secondary minerals). There is also clear evidence for variations in uranium species from the microscopic to the macroscopic scale. However, similarities in speciation at sites having different source terms suggest that soil and groundwater chemistry may be as important as source term in defining the uranium speciation in these soils. Characterization of treated soils has focused on materials from two sites that have undergone leaching using conventional extractants (e.g., carbonate, citrate) or novel chelators such as Tiron. Redox reagents have also been used to facilitate the leaching process. Three different classes of treated soils have been identified based on the speciation of uranium remaining in the soils. In general, the effective treatments decrease the total uranium while increasing the ratio of U(IV) to U(VI) species.

  1. The determination of minor isotope abundances in naturally occurring uranium materials. The tracing power of isotopic signatures for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Ovaskainen, R

    1999-11-01

    The mass spectrometric determination of minor abundant isotopes, {sup 234}U and {sup 236}U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the thermal ionisation mass spectrometer Finnigan MAT 262RPQ was used. It was equipped with 6 Faraday cups and a Secondary Electron Multiplier (SEM), which was operated in pulse counting mode for the detection of extremely low ion currents. The dynamic measurement range was increased considerably combining these two different detectors. The instrument calibration was performed carefully. The linearity of each detector, the deadtime of the ion counting detector, the detector normalisation factor, the baseline of each detector and the mass discrimination in the ion source were checked and optimised. A measurement technique based on the combination of a Gas Source Mass Spectrometry (GSMS) and a Thermal Ionisation Mass Spectrometry (TIMS) was developed for the accurate determination of isotopic composition in naturally occurring uranium materials. Because the expected ratio of n({sup 234}U)/n({sup 238}U) exceeded the dynamic measurement range of the Faraday detectors of the TIMS instrument, an experimental design using a combination of two detectors was developed. The n({sup 234}U)/n({sup 235}U) and n({sup 236}U)/n({sup 235}U) ratios were determined using ion counting in combination with the decelerating device. The n({sup 235}U)/n({sup 238}U) ratio was determined by the Faraday detector. This experimental design allowed the detector cross calibration to be circumvented. Precisions of less than 1 percent for the n({sup 234}U)/n({sup 235}U) ratios and 5-25 percent for the n({sup 236}U)/n({sup 235}U) ratios were achieved. The purpose of the study was to establish a register of isotopic signatures for natural uranium materials. The amount ratio, and isotopic composition of 18 ore concentrates, collected by the International

  2. Fluorescence derivatization of clarithromycin for high performance liquid chromatographic determination with fluorescence detection

    OpenAIRE

    Boonleang, J.

    2007-01-01

    Clarithromycin (CAM) is a semisynthetic macrolide antibiotic whose chemical structure has no suitable chromophore for highly sensitive and accurate direct determination. The aim of this study was toderivatize CAM with fluorescence-labeling compounds capable of enhancing the sensitivity of CAM determination. Two fluorescence-labeling compounds were used in this study, 9-fluorenylmethyloxycarbonylchloride (FMOC-Cl) and 1-naphthylisocyanate (NIC), both of which gave the fluorescent derivatives o...

  3. Volumetric determination of uranium using titanous sulfate as reductant before oxidimetric titration

    Science.gov (United States)

    Wahlberg, James S.; Skinner, Dwight L.; Rader, Lewis F.

    1956-01-01

    A new method for determining uranium in samples containing 0.05 percent or more U3O8, using titanous sulfate as reducing agent, is much shorter, faster, and has fewer interferences than conventional methods using reductor columns. The sample is dissolved with sulfuric, nitric, perchloric, and hydrofluoric acids. Elements that would otherwise form insoluble fluorides are kept in solution by complexing the fluoride ion with boric acid. A precipitation is made with cupferron to remove interfering elements. The solution is filtered to remove the precipitated cupferrates instead of extracting them with chloroform as is usually done. Filtration is preferred to extraction because any niobium that may be in solution forms an insoluble cupferrate that may be removed by filtering but is very difficult to extract with chloroform. Excess cupferron is destroyed by oxidizing with nitric and perchloric acids, and evaporating to dense fumes of sulfuric acid. The uranium is reduced to U(IV) by the addition of titanous sulfate, with cupric sulfate used as an indicator of the completeness of the reduction. Metallic copper is formed when all the uranium is reduced. The reduced copper is then reoxidized by the addition of mercuric perchlorate, an excess of ferric sulfate added, and the solution titrated immediately with standard ceric sulfate with ferroin as an indicator. Precision of the method compared favorable with methods in common use, both for uranium ores and for most types of uranium-rich materials.

  4. On the distribution of uranium in hair: Non-destructive analysis using synchrotron radiation induced X-ray fluorescence microprobe techniques

    Energy Technology Data Exchange (ETDEWEB)

    Israelsson, A., E-mail: axel.israelsson@liu.se [Department of Medical and Health Sciences, Linköping University, 58183 Linköping (Sweden); Eriksson, M. [Swedish Radiation Safety Authority, 17116 Stockholm (Sweden); Pettersson, H.B.L. [Department of Radiation Physics, Linköping University, 58183 Linköping (Sweden); Department of Medical and Health Sciences, Linköping University, 58183 Linköping (Sweden)

    2015-06-01

    In the present study the distribution of uranium in single human hair shafts has been evaluated using two synchrotron radiation (SR) based micro X-ray fluorescence techniques; SR μ-XRF and confocal SR μ-XRF. The hair shafts originated from persons that have been exposed to elevated uranium concentrations. Two different groups have been studied, i) workers at a nuclear fuel fabrication factory, exposed mainly by inhalation and ii) owners of drilled bedrock wells exposed by ingestion of water. The measurements were carried out on the FLUO beamline at the synchrotron radiation facility ANKA, Karlsruhe. The experiment was optimized to detect U with a beam size of 6.8 μm × 3 μm beam focus allowing detection down to ppb levels of U in 10 s (SR μ-XRF setup) and 70 s (SR confocal μ-XRF setup) measurements. It was found that the uranium was present in a 10–15 μm peripheral layer of the hair shafts for both groups studied. Furthermore, potential external hair contamination was studied by scanning of unwashed hair shafts from the workers. Sites of very high uranium signal were identified as particles containing uranium. Such particles, were also seen in complementary analyses using variable pressure electron microscope coupled with energy dispersive X-ray analyzer (ESEM–EDX). However, the particles were not visible in washed hair shafts. These findings can further increase the understanding of uranium excretion in hair and its potential use as a biomonitor. - Highlights: • Uranium at the fg level was detectable and the uranium distribution in single hair shafts was derived. • The uranium is located peripherally on the shafts in what seems to be a layer of approximately 10-15 μm thickness. • Uranium bearing particles were found on hairs that had not been washed.

  5. Optimal Fluorescence Waveband Determination for Detecting Defective Cherry Tomatoes Using a Fluorescence Excitation-Emission Matrix

    Directory of Open Access Journals (Sweden)

    In-Suck Baek

    2014-11-01

    Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.

  6. Determination of the isotopic composition of natural and slightly enriched uranium by alpha-spectrometry

    DEFF Research Database (Denmark)

    Kunzendorf, Helmar

    1968-01-01

    Determinations of the isotope contents of 238U, 235U and 234U in five uranium samples containing 0–5 at% 235U were carried out on the basis of a least-squares fit of the α-spectra from the samples, measured with a semiconductor detector, to the theoretically expected α-spectra. With a simple source...

  7. Determination of carbon in uranium and its compounds; Determinacion de carbono en uranio metal y sus compuestos

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Garcia, M. M.

    1972-07-01

    This paper collects the analytical methods used our laboratories for the determination of carbon in uranium metal, uranate salts and the oxides, fluorides and carbides of uranium. The carbon is usually burned off in a induction or resistance oven under oxygen flow. The CO{sub 2} is collected in barite solution. Where it is backtitrated with potassium biphthalate. (Author)

  8. DETERMINATION OF AMINOGLYCOSIDES IN FOOD BY FLUORESCENCE POLARIZATION IMMUNOASSAY

    Directory of Open Access Journals (Sweden)

    FARAFONOVA O.V.

    2015-01-01

    Full Text Available The methodic for quantitative determination of aminoglycoside antibiotics (gentamicin, kanamycin, streptomycin, amikacin, neomycin in food by polarization fluorescent immunoassay (FPIA is developed. The size and structure influence of a fluorescent molecule on a fluorescence polarization degree is analyzed. Affinity constants of antibodies to compounds and tracers were estimated, optimized working concentration of tracers and antibodies that provide the maximum value of analytical signal. Methods were tested in the antibiotics identification in milk, eggs and chicken.

  9. Pulp tissue in sex determination: A fluorescent microscopic study

    Directory of Open Access Journals (Sweden)

    Amit Nayar

    2014-01-01

    Full Text Available Aims: To determine and compare the reliability of pulp tissue in determination of sex and to analyze whether caries have any effect on fluorescent body test. Materials and Methods: This study was carried on 50 maxillary and mandibular teeth (25 male teeth and 25 female teeth, which were indicated for extraction. The teeth are categorized into 5 groups, 10 each (5 from males and 5 from females on the basis of caries progression. The pulp cells are stained with quinacrine hydrochloride and observed with fluorescent microscope for fluorescent body. Gender is determined by identification of Y chromosome fluorescence in dental pulp. Results: Fluorescent bodies were found to be more in sound teeth in males as the caries increase the mean percentage of fluorescent bodies observed decreases in males. We also observed the fluorescent spots in females, and the value of the spot increases in female as the caries progresses, thereby giving false positive results in females. Conclusion: Sex determination by fluorescent staining of the Y chromosome is a reliable technique in teeth with healthy pulps or caries with enamel or up to half way of dentin. Teeth with caries involving pulp cannot be used for sex determination.

  10. Determination of kinetic coefficients for the simultaneous reduction of sulfate and uranium by Desulfovibrio desulfuricans bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, M.D.

    1995-05-01

    Uranium contamination of groundwaters and surface waters near abandoned mill tailings piles is a serious concern in many areas of the western United States. Uranium usually exists in either the U(IV) or the U(VI) oxidation state. U(VI) is soluble in water and, as a result, is very mobile in the environment. U(IV), however, is generally insoluble in water and, therefore, is not subject to aqueous transport. In recent years, researchers have discovered that certain anaerobic microorganisms, such as the sulfate-reducing bacteria Desulfovibrio desulfuricans, can mediate the reduction of U(VI) to U(IV). Although the ability of this microorganism to reduce U(VI) has been studied in some detail by previous researchers, the kinetics of the reactions have not been characterized. The purpose of this research was to perform kinetic studies on Desulfovibrio desulficans bacteria during simultaneous reduction of sulfate and uranium and to determine the phase in which uranium exists after it has been reduced and precipitated from solution. The studies were conducted in a laboratory-scale chemostat under substrate-limited growth conditions with pyruvate as the substrate. Kinetic coefficients for substrate utilization and cell growth were calculated using the Monod equation. The maximum rate of substrate utilization (k) was determined to be 4.70 days{sup {minus}1} while the half-velocity constant (K{sub s}) was 140 mg/l COD. The yield coefficient (Y) was determined to be 0.17 mg cells/mg COD while the endogenous decay coefficient (k{sub d}) was calculated as 0.072 days{sup {minus}1}. After reduction, U(IV) Precipitated from solution in the uraninite (UO{sub 2}) phase. Uranium removal efficiency as high as 90% was achieved in the chemostat.

  11. Thermophoresis of DNA determined by microfluidic fluorescence.

    Science.gov (United States)

    Duhr, S; Arduini, S; Braun, D

    2004-11-01

    We describe a microfluidic all-optical technique to measure the thermophoresis of molecules. Within micrometer-thick chambers, we heat aqueous solutions with a micrometer-sized focus of infrared light. The temperature increase of about 1 K is monitored with temperature-sensitive fluorescent dyes. We test the approach in measuring the thermophoresis of DNA. We image the concentration of DNA in a second fluorescence-color channel. DNA is depleted away from the heated spot. The profile of depletion is fitted by the thermophoretic theory to reveal the Soret coefficient. We evaluate the method with numerical 3D calculations of temperature profiles, drift, convection and thermophoretic depletion using finite element methods. The approach opens new ways to monitor thermophoresis at the single molecule level, near boundaries and in complex mixtures. The flexible microfluidic setting is a good step towards microfluidic applications of thermophoresis in biotechnology.

  12. The Determination and Estimation of Arsenic and Uranium in Private Wells throughout the United States

    Science.gov (United States)

    Frederick, L.; Johnson, W. P.; Vanderslice, J.; Taddie, M.; Malecki, K.; Gregg, J.; Faust, N.

    2014-12-01

    Approximately 45 million Americans rely on private wells or small systems for their domestic water supply1. With the exception of a few states (e.g., WA and NJ), private wells or systems serving fewer than 15 connections are not required by the Safe Drinking Water Act to regularly monitor water quality1. This is a public health concern as a lack of monitoring/information can lead to prolonged exposure to levels of contaminants that pose health risks such as arsenic and uranium. Based on data from the United States Geologic Survey's National Water Information System (NWIS), arsenic and uranium exceeded their respective maximum contaminant levels (MCL), set by the Environmental Protection Agency, in 11% and 4% of the wells tested, respectively. As monitoring is not required, but the presence of contamination is possible, it is important to be able to estimate the likelihood of an unmonitored well to be contaminated with arsenic or uranium. A national model was developed using NWIS data from ~260,000 wells across the United States and PMPE data (Precipitation minus evapotranspiration). CART analysis was used to determine the likelihood of a well to have arsenic based on geochemical and hydrometerological parameters. PMPE was the most important determiner of arsenic mobility, followed by pH and pe. Of the two, pH was primary in driest environments, and dissolved iron (proxy for pe) was primary in wetter environments. Uranium analysis on CART is still pending. It is expected that PMPE will also be the primary determiner of uranium mobility followed by pe for all environments. Using this information, the national model can predict the likelihood of a well to have arsenic or uranium based on location and other geochemical parameters previously measured. To estimate arsenic and uranium in wells that have never been monitored requires use of geospatial statistical tools like kriging to fill in the areas where no information is known. In these areas it is impossible to have

  13. Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range.

    Science.gov (United States)

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2011-07-01

    A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV-MSFIA makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and uranium(VI) in a wide concentration range (0-1,200 and 0-2,000 μg L(-1) Th and U, respectively). Limits of detection reached are 5.9 ηg L(-1) of uranium and 60 ηg L(-1) of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method.

  14. Methods of Uranium Determination in solutions of Tributyl Phosphate and Kerosene; Metodos de determinacion de uranio en soluciones de fosfato de tributilo y queroseno

    Energy Technology Data Exchange (ETDEWEB)

    Petrement Eguiluz, J.; Palomares Delgado, F.

    1962-07-01

    A new analytical method for the determination of uranium in organic solutions of tributyl phosphate and kerosene is proposed. In this method the uranium is reectracted from the aqueous phase by reduction with cadmium in acid solution. The uranium can be determined in this solution by the usual methods. In case of very diluted solutions, a direct spectrophtometrical determination of uranium in the organic phase with dibenzoylmethane is proposed. (Author) 21 refs.

  15. [The intraoperative determination of intestinal vitality with a fluorescent indicator].

    Science.gov (United States)

    Ivanov, A; Terziev, I

    1997-01-01

    Intestinal obstruction due to strangulation is induced in dogs under experimental conditions, with intestinal wall vitality assessment done on the ground of standard clinical criteria, using fluorescence dye and UV rays, as well as histological study. Sensitivity, specificity and prognostic value of each of the methods employed are determined. The fluorescence method advantages are recorded, and the prospects of its clinical implementation are estimated.

  16. Determination of uranium concentration in ground water samples of Northern Greece

    Directory of Open Access Journals (Sweden)

    Pashalidis I.

    2012-04-01

    Full Text Available The activity concentration of 238U and 234U has been determined in groundwater samples of hot springs and deep wells from the region of Northern Greece. The analysis was performed by alpha spectroscopy after pre-concentration and separation of uranium by cation exchange (Chelex 100 resin and finally its electro-deposition on stainless steel discs. The uranium concentration in deep wells and springs varies strongly between 0.15 and 7.66 μg l−1. Generally the springs present higher uranium concentration than the deep wells, except of the Apol-lonia spring, which has shown the lowest value of 0.15 mg l−1. 238U and 234U activity concentration ranged between 1.8–95.3 mBq l−1 and 1.7–160.1 mBq l−1, respectively. The obtained isotopic ratio 234U/238U varies between 0.95 and 1.74 which means that the two isotopes are not in radioactive equilibrium. The highest 234U/238U activity ratio values correspond to the Langada springs, indicating most probably old-type waters. On the other hand, ground waters from wells with relatively low uranium activity concentration and low 234U/238U isotopic ratios, point to the presence of younger waters with a stronger contribution of a local recharge component to the groundwater.

  17. Determination of uranium from nuclear fuel in environmental samples using inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen]|[Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen

    2000-11-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The {sup 236}U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on inductively coupled plasma quadrupole mass spectrometry with a hexapole collision cell (HEX-ICP-QMS). The figures of merit of the HEX-ICP-QMS were studied with a plasma-shielded torch using different nebulizers (such as an ultrasonic nebulizer (USN) and Meinhard nebulizer) for solution introduction. A {sup 238}U{sup +} ion intensity of up to 27000 MHz/ppm in HEX-ICP-QMS with USN was observed by introducing helium into the hexapole collision cell as the collision gas at a flow rate of 10 ml min{sup -1}. The formation rate of uranium hydride ions UH{sup +}/U{sup +} of 2 x 10{sup -6} was obtained by using USN with a membrane desolvator. The limit of {sup 236}U/{sup 238}U ratio determination in 10 {mu}g 1{sup -1} uranium solution was 3 x 10{sup -7} corresponding to the detection limit for {sup 236}U of 3 pg 1{sup -1}. The precision of uranium isotopic ratio measurements in 10 {mu}g 1{sup -1} laboratory uranium isotopic standard solution was 0.13% ({sup 235}U/{sup 238}U) and 0.33% ({sup 236}U/{sup 238}U) using a Meinhard nebulizer and 0.45% ({sup 235}U/{sup 238}U) and 0.88% ({sup 236}U/{sup 238}U) using a USN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the {sup 236}U/{sup 238}U ratio ranged from 10{sup -5} to 10{sup -3}. (orig.)

  18. Determination of (210)Po and uranium in high salinity water samples.

    Science.gov (United States)

    Grabowski, Paweł; Bem, Henryk

    A method for the determination of uranium and (210)Po in high salinity water samples has been elaborated. Both radionuclides are preconcentrated from 0.5 dm(3) saline media by co-precipitation with hydrated manganese dioxide, followed by dissolution of the precipitate in 200 mL of 1 M HCl. Uranium isotopes (235)U and (238)U can be directly determined by ICP MS method with a detection limit of 0.01 ppb for (238)U. Prior to a selective determination of (210)Po, the majority of other naturally occurring α-emitting radionuclides (uranium, thorium and protactinium) can be stripped from this solution by their extraction with a 50% solution of HDEHP in toluene. Finally, (210)Po is simply separated by direct transfer to an extractive scintillator containing 5% of trioctylphosphine oxide in Ultima Gold F cocktail and determined by an α/β separation liquid scintillation technique with detection limit below 0.1 mBq/dm(3).

  19. Quantitative Determination of DNA-Ligand Binding Using Fluorescence Spectroscopy

    Science.gov (United States)

    Healy, Eamonn F.

    2007-01-01

    The effective use of fluorescence spectroscopy for determining the binding of the intercalcating agent crhidium bromide to DNA is being described. The analysis used simple measurement techniques and hence can be easily adopted by the students for a better understanding.

  20. Simultaneous Determination of Large Amount of Uranium and Trace Fission Elements by DRC-ICP-MS

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Lei; LI; Hui-bo; LIU; Fang; HE; Hui; CONG; Hai-feng

    2013-01-01

    Large amount of uranium and trace fission product elements are widely exist in reprocessing process.Since the difference of elements concentration,chemical separation and various dilution ratios should be used to obtain all the values.Inductively coupled plasma mass spectrometry(ICP-MS)can be used to determination of more than 75%elements in the periodic table and meet the needs for analysis of fission

  1. Intercomparison run for uranium and tritium determination in urine samples, organised by Nuclear Regulatory Authority, Argentina

    CERN Document Server

    Serdeiro, N H; Equillor, H E

    2003-01-01

    The Nuclear Regulatory Authority (ARN), Argentina, has carried out an intercomparison run for tritium and uranium determination in urine, in November 2002. The aim of this exercise was to assess the performance of the laboratories that usually inform these radionuclides and to provide technical support in order to have an appropriate occupational monitoring in vitro. In the present work, the results of the intercomparison and the assessment of each laboratory are published.

  2. Determination of specific activity of 230Th in uranium ore samples

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new method suitable for determining specific activity of 230Th in uranium ore samples is built. The method is characterized by adding the 230Th/ 232Th standard dilution agent with lower activity ratio (Its 230Th/ 232Th activity ratio and 230Th have been known) to the samples and using isotopic dilution analysis. The method can be applied to analyses of 230Th specific activity in various 230Th/ 232Th activity ratio samples. The precision can also be improved.

  3. Determination of uranium and polonium in Spa rus aura ta by alpha spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Luna P, M.; Renteria, M.; Montero C, M. E. [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes No. 120, Complejo Industrial Chihuahua, 31109 Chihuahua (Mexico); Manjon C, G.; Diaz, I., E-mail: elena.montero@cimav.edu.mx [Universidad de Sevilla, Escuela Tecnica Superior de Arquitectura, Departamento de Fisica Aplicada II, San Fernando No. 4, 41004 Sevilla (Spain)

    2012-06-15

    The aim of this study was optimizing conditions for the specific activities determination of some uranium-series radionuclides present in Spa rus aura ta by alpha spectrometry. Determinations of specific activities were conducted varying the type of digestion: acid attack on hot plate, controlled microwave digestion and acid attack after calcination of the sample. The latter procedure was applied only to the case of uranium isotopes determination. The variation in the isotope extraction method consisted of applying the techniques of liquid-liquid extracting using Tributyl phosphate or chromatographic UTEVA resin. Results depending on the type of treatment given to the samples were compared based on obtained chemical yields. The results reveal a higher bioaccumulation of polonium in the liver sample, with activities of 0.809, 2.495 and 2.439 Bq kg{sup -1} fresh wt compared with the fillet. The best chemical yields of polonium were close to 60% for samples that were digested by microwave. In the case of uranium the best chemical yields, close to 80% for fillet, were obtained with a previous calcination of the sample and using the UTEVA resin. (Author)

  4. Lab on valve-multisyringe flow injection system (LOV-MSFIA) for fully automated uranium determination in environmental samples.

    Science.gov (United States)

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2011-06-15

    The hyphenation of lab-on-valve (LOV) and multisyringe flow analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell (LWCC), allows the spectrophotometric determination of uranium in different types of environmental sample matrices, without any manual pre-treatment, and achieving high selectivity and sensitivity levels. On-line separation and preconcentration of uranium is carried out by means of UTEVA resin. The potential of the LOV-MSFIA makes possible the fully automation of the system by the in-line regeneration of the column. After elution, uranium(VI) is spectrophotometrically detected after reaction with arsenazo-III. The determination of levels of uranium present in environmental samples is required in order to establish an environmental control. Thus, we propose a rapid, cheap and fully automated method to determine uranium(VI) in environmental samples. The limit of detection reached is 1.9 ηg of uranium and depending on the preconcentrated volume; it results in ppt levels (10.3 ηg L(-1)). Different water sample matrices (seawater, well water, freshwater, tap water and mineral water) and a phosphogypsum sample (with natural uranium content) were satisfactorily analyzed.

  5. Spectrographic determination of impurities in uranium tetrafluoride; Determinacion espectrografica de impurezas en tetrafluoruro de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Capdevila Perez, C.; Roca Adell, M.; Alvarez Gonzalez, F.

    1967-07-01

    A carrier distillation method for the determination of Ag, Al, As, B, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Si in uranium tetrafluoride was develop ped. the previous addition of 25% Y{sub 2}3 prevents the excitation of uranium by conversion of the volatile UF{sub 4} into U{sub 3}0{sub 8} during the arc discharge. NaCl or Ga{sub 2}0{sub 3}, containing Ge and V as internal standards, are used as carriers, and samples are arced in 10 Amp. d.c. arc in a graphite anode cup. 7 mm diameter, 10 mm deep, being the weight of charge 300 mg. (Author) 14 refs.

  6. Determination of the Galaxy age by the method of uranium-thorium-plutonium isotopic ratios

    Science.gov (United States)

    Panov, I. V.; Lutostansky, Yu. S.; Eichler, M.; Thielemann, F.-K.

    2017-07-01

    The dependence of the Galaxy age ( T G), as determined by the method of uranium-thorium isotopic ratios, on the parameters of the nucleosynthesis model is studied within the theory of galactic nucleosynthesis. It is shown that TG depends strongly both on the scenario of the production of nuclei in the r-process and those features of neutron-rich nuclei that are used in the respective analysis and on galactic-nucleosynthesis parameters. The effect of a sudden nucleosynthesis spike before the formation of a solar system on the Galaxy age is evaluated. The region of admissible values of the parameters of galacticnucleosynthesis theory is discussed. The method of uranium-thorium isotopic ratios is supplemented with the 244Pu/238U ratio for yet another cosmochronometer pair, and the Galaxy age is estimated on the basis of the model modified in this way.

  7. Standard test method for radiochemical determination of uranium isotopes in soil by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers the determination of alpha-emitting uranium isotopes in soil. This test method describes one acceptable approach to the determination of uranium isotopes in soil. 1.2 The test method is designed to analyze 10 g of soil; however, the sample size may be varied to 50 g depending on the activity level. This test method may not be able to completely dissolve all forms of uranium in the soil matrix. Studies have indicated that the use of hydrofluoric acid to dissolve soil has resulted in lower values than results using total dissolution by fusion. 1.3 The lower limit of detection is dependent on count time, sample size, detector, background, and tracer yield. The chemical yield averaged 78 % in a single laboratory evaluation, and 66 % in an interlaboratory collaborative study. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, ass...

  8. Automated Controlled-Potential Coulometric Determination of Uranium (Determination de l’Uranium par Coulometre Automatise a Potentiel Controle),

    Science.gov (United States)

    1982-06-01

    CPC) is an analytical technique commonly used in the nuclear industry for determination of electroactive metals (1). At Chalk River Nuclear...removed from the samples (by fuming), it can be tolerated in concentrations up to 5 M as long as sufficient sulphamic acid is added to destroy any...used and the mercury used in the coulometer cell was triple-distilled grade. Saturated sulphamic acid was prepared by the dissolution of =15 g of

  9. Determining factors in the elimination of uranium and radium from groundwaters during a standard potabilization process

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A. [Departamento de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. de la Universidad s/n 10071 Caceres (Spain)], E-mail: ymiralle@unex.es; Salas, A. [Departamento de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. de la Universidad s/n 10071 Caceres (Spain); Legarda, F. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Superior de Ingenieros, Universidad de Pais Vasco, Alameda de Urquijo s/n 48013 Bilbao (Spain)

    2008-11-15

    We studied the physico-chemical and radioactive characteristics of four waters of subsurface origin. They were chosen for having the highest natural radioactivity levels of waters for human consumption in the Autonomous Community of Extremadura, Spain Their activity levels for alpha emitting radionuclides are between 120 and 19 300 mBq L{sup -1}, all exceeding the 100 mBq L{sup -1} threshold established in the European Union above which radioactive isotopes that are present in water should be investigated to determine which corrective action, if any, is needed. These waters were used to compare the efficiency in eliminating their uranium and radium content of two potabilization processes - one the standard chlorination-only process used by their respective municipalities, and the other a procedure consisting of coagulation, flocculation, settling, filtration, and chlorination stages, specifically designed to maximize the elimination of their natural radioactive content. The results showed the uranium and radium elimination efficiencies to depend strongly on the water's hydrogencarbonate, calcium, and magnesium ion concentrations. In particular, with increasing concentrations of any of these ions, the uranium elimination efficiency fell from 90% to 60% at its optimal working pH, pH = 6, while the radium elimination efficiency rose from 50% to 90% at its optimal working pH, pH = 10.

  10. Standard guide for determination of plutonium and neptunium in uranium hexafluoride by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This method covers the determination of plutonium and neptunium isotopes in uranium hexafluoride by alpha spectroscopy. The method can also be applicable to any matrix that may be converted to a nitric acid system. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

  11. Determination of uranium and thorium in complex samples using chromatographic separation, ICP-MS and spectrophotometric detection.

    Science.gov (United States)

    Rozmarić, Martina; Ivsić, Astrid Gojmerac; Grahek, Zeljko

    2009-11-15

    The paper describes a research of possible application of UTEVA and TRU resins and anion exchanger AMBERLITE CG-400 in nitrate form for the isolation of uranium and thorium from natural samples. The results of determination of distribution coefficient have shown that uranium and thorium bind on TRU and UTEVA resins from the solutions of nitric and hydrochloric acids, and binding strength increases proportionally to increase the concentration of acids. Uranium and thorium bind rather strongly to TRU resin from the nitric acid in concentration ranging from 0.5 to 5 mol L(-1), while large quantities of other ions present in the sample do not influence on the binding strength. Due to the difference in binding strength in HCl and HNO(3) respectively, uranium and thorium can be easily separated from each other on the columns filled with TRU resin. Furthermore, thorium binds to anion exchanger in nitrate form from alcohol solutions of nitric acid very strongly, while uranium does not, so they can be easily separated. Based on these results, we have created the procedures of preconcentration and separation of uranium and thorium from the soil, drinking water and seawater samples by using TRU and UTEVA resins and strong base anion exchangers in nitrate form. In one of the procedures, uranium and thorium bind directly from the samples of drinking water and seawater on the column filled with TRU resin from 0.5 mol L(-1) HNO(3) in a water sample. After binding, thorium is separated from uranium with 0.5 mol L(-1) HCl, and uranium is eluted with deionised water. By applying the described procedure, it is possible to achieve the concentration factor of over 1000 for the column filled with 1g of resin and splashed with 2L of the sample. Spectrophotometric determination with Arsenazo III, with this concentration factor results in detection limits below 1 microg L(-1) for uranium and thorium. In the second procedure, uranium and thorium are isolated from the soil samples with TRU

  12. Sucrose monoester micelles size determined by Fluorescence Correlation Spectroscopy (FCS.

    Directory of Open Access Journals (Sweden)

    Susana A Sanchez

    Full Text Available One of the several uses of sucrose detergents, as well as other micelle forming detergents, is the solubilization of different membrane proteins. Accurate knowledge of the micelle properties, including size and shape, are needed to optimize the surfactant conditions for protein purification and membrane characterization. We synthesized sucrose esters having different numbers of methylene subunits on the substituent to correlate the number of methylene groups with the size of the corresponding micelles. We used Fluorescence Correlation Spectroscopy (FCS and two photon excitation to determine the translational D of the micelles and calculate their corresponding hydrodynamic radius, R(h. As a fluorescent probe we used LAURDAN (6-dodecanoyl-2-dimethylaminonaphthalene, a dye highly fluorescent when integrated in the micelle and non-fluorescent in aqueous media. We found a linear correlation between the size of the tail and the hydrodynamic radius of the micelle for the series of detergents measured.

  13. Simultaneous Determination of Magnolol and Honokiol by Synchronous Fluorescence Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Min ZHANG; Li Ming DU

    2006-01-01

    A simple sensitive and quick assay for simultaneously determining magnolol (MOL)and honokiol (HOL) has been described based on their natural fluorescence. This method is based on the fact that synchronous fluorometry could resolve the overlapping of fluorescence spectra, which was aroused by their similar molecular structures. In this work, the synchronous spectrum, maintaining a constant difference of Δλ =10 nm between the emission and excitation wavelengths, has been selected for the determination of HOL and MOL. Under the optimum conditions, the fluorescence intensity is proportional to the concentration of MOL and HOL in solution over the range 0.075-0.7 μg/mL and 0.05-0.9 μg/mL with the detection limit of 0.029 μg/mL and 0.019 μg/mL, respectively. The method was applied to the simultaneous determination of MOL and HOL in pharmaceutical dosage with satisfactory results.

  14. Differential pulse cathodic stripping voltammetric determination of uranium with arsenazo-III at the hanging mercury dropping electrode

    Energy Technology Data Exchange (ETDEWEB)

    Kadi, M.W.; El-Shahawi, M.S. [Chemistry Dept., King Abdulaziz Univ., Jeddah (Saudi Arabia)

    2009-07-01

    An accurate, inexpensive and less laborious controlled adsorptive accumulation of uranium(VI)-arsenazo-III on a hanging mercury drop electrode (HMDE) has been developed for uranium(VI) determination. The method is based upon the collection of uranium(VI)-arsenazo-III complex at pH 5-6 at the HMDE and subsequent direct stripping measurement of the element in the nanomolar concentration level. The cathodic peak current (i{sub p,c}) of the adsorbed complex ions of uranium(VI) was measured at -0.35 V vs. Ag/AgCl reference electrode by differential pulse cathodic stripping voltammetry (DP-CSV), proceeded by an accumulation period of 150s2.5 in Britton-Robinson buffer of pH 5. The plot of the resulting i{sub p,c} vs. uranium(VI) concentration was linear in the range 2.1 x 10{sup -9} to 9.60 x 10{sup -7} mol L{sup -1} uranium(VI) and tended to level off at above 9.6 x 10{sup -7} mol L{sup -1}. The limits of detection and quantification of uranium(VI) were found to be 4.7 x 10{sup -10} and 1.5 x 10{sup -9} mol L{sup -1}, respectively. A relative standard deviation of {+-}2.39% (n = 5) at 8.5 x 10{sup -7} mol L{sup -1} uranium(VI) was obtained. The method was validated by comparing the results with that obtained by ICP-MS method with RSD less than {+-}3.3%. The method was applied successfully for the analysis of uranium in certified reference material (IAEA soil-7), and in phosphate fertilizers. (orig.)

  15. Fluorescence derivatization of clarithromycin for high performance liquid chromatographic determination with fluorescence detection

    Directory of Open Access Journals (Sweden)

    Boonleang, J.

    2007-03-01

    Full Text Available Clarithromycin (CAM is a semisynthetic macrolide antibiotic whose chemical structure has no suitable chromophore for highly sensitive and accurate direct determination. The aim of this study was toderivatize CAM with fluorescence-labeling compounds capable of enhancing the sensitivity of CAM determination. Two fluorescence-labeling compounds were used in this study, 9-fluorenylmethyloxycarbonylchloride (FMOC-Cl and 1-naphthylisocyanate (NIC, both of which gave the fluorescent derivatives of CAM with approximately the same fluorescence intensity. The derivatization reactions in the concentration rangestudied (0.1-2.4 μg/ml were reproducible with coefficient of variation of less than 6.01% and the fluorescence responses were linearly proportional to CAM concentration with r2 of greater than 0.99. The reaction of CAM with FMOC-Cl optimally occurred in a solvent mixture of acetonitrile and phosphate buffer pH 7.5(4:1 volume ratio at 40oC for 40 min. The optimum derivatization reaction of CAM with NIC took place in acetonitrile with triethylamine as catalyst at 30oC for 60 min. It was mild and quantitative giving CAM-NICfluorescent derivative, which is more stable at room temperature than CAM-FMOC derivative. This derivatization should, therefore, be more applicable for highly sensitive CAM determination especially for thestudy involving the analysis of several samples.

  16. Fluorescence determination of acrylamide in heat-processed foods.

    Science.gov (United States)

    Liu, Congcong; Luo, Feng; Chen, Dongmei; Qiu, Bin; Tang, Xinhua; Ke, Huixian; Chen, Xi

    2014-06-01

    A simple and rapid fluorescence method has been developed for the determination of acrylamide in heat-processed food samples. In the determination, acrylamide is degraded through Hofmann reaction to generate vinyl amine, and pyrrolinone is produced when the vinyl amine reacts with fluorescamine, resulting in a strong fluorescence emission at 480 nm. Hofmann reaction is a key step for the fluorescence determination of acrylaminde, and the reaction conditions are investigated and optimized. Under the optimal conditions, the fluorescence intensity increases with the increase of acrylamide concentrations. The linear range between the fluorescence intensity and the square-root of acrylamide concentrations is from 0.05 μg mL(-1) to 20 μg mL(-1) with the correlation coefficient R(2)=0.9935. The detection limit is 0.015 μg mL(-1) and the recovery for food samples is from 66.0% to 110.6%. In comparison with Specification of Entry&Exit Inspection and Quarantine Bureau of The People׳s Republic of China (SN/T 2281-2009), the method showed comparable results and demonstrated the accuracy of the method.

  17. Standard test methods for analysis of sintered gadolinium oxide-uranium dioxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the analysis of sintered gadolinium oxide-uranium dioxide pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Section Carbon (Total) by Direct CombustionThermal Conductivity Method C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Chlorine and Fluorine by Pyrohydrolysis Ion-Selective Electrode Method C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Gadolinia Content by Energy-Dispersive X-Ray Spectrometry C1456 Test Method for Determination of Uranium or Gadolinium, or Both, in Gadolinium Oxide-Uranium Oxide Pellets or by X-Ray Fluorescence (XRF) Hydrogen by Inert Gas Fusion C1457 Test Method for Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas Extraction Isotopic Uranium Composition by Multiple-Filament Surface-Ioni...

  18. Fluorine and chlorine determination in mixed uranium-plutonium oxide fuel and plutonium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Elinson, S.V.; Zemlyanukhina, N.A.; Pavlova, I.V.; Filatkina, V.P.; Tsvetkova, V.T.

    1981-01-01

    A technique of fluorine and chlorine determination in the mixed uranium-plutonium oxide fuel and plutonium dioxide, based on their simultaneous separation by means of pyrohydrolysis, is developed. Subsequently, fluorine is determined by photometry with alizarincomplexonate of lanthanum or according to the weakening of zirconium colouring with zylenol orange. Chlorine is determined using the photonephelometric method according to the reaction of chloride-ion interaction with silver nitrate or by spectrophotometric method according to the reaction with mercury rhodanide. The lower limit of fluorine determination is -6x10/sup -5/ %, of chlorine- 1x10/sup -4/% in the sample of 1g. The relative mean quadratic deviation of the determination result (Ssub(r)), depends on the character of the material analyzed and at the content of nx10/sup -4/ - nx10/sup -3/ mass % is equal to from 0.05 to 0.32 for fluorine and from 0.11 to 0.35 for chlorine.

  19. Fast and accurate expression for the Voigt function. Application to the determination of uranium M linewidths

    Energy Technology Data Exchange (ETDEWEB)

    Limandri, Silvina P. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000, Cordoba (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina); Bonetto, Rita D. [Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina) and Centro de Investigacion y Desarrollo en Ciencias Aplicadas Dr. Jorge Ronco, Calle 47 No 257, 1900 La Plata, Argentina; Facultad de Ciencias Exactas y Facultad de Ingenieria de la UNLP, La Plata (Argentina); Di Rocco, Hector O. [Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina); Instituto de Fisica Arroyo Seco, Facultad de Ciencias Exactas, Universidad Nacional del Centro, Pinto 399, 7000 Tandil (Argentina); Trincavelli, Jorge C. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000, Cordoba (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina)], E-mail: jorge@quechua.fis.uncor.edu

    2008-09-15

    The Voigt function is the convolution between a Gaussian and a Lorentzian distribution. The numerical implementation of this function is required in diverse areas of physics and applied mathematics. An explicit representation for the Voigt function is developed in terms of series of trigonometric and hyperbolic functions. The obtained expression permits a very fast evaluation of Voigt profiles with a degree of accuracy higher than the one required for spectroscopy applications. In addition, this expression is implemented in a numerical algorithm of parameter optimization in electron probe microanalysis, and applied to determine natural linewidths for several transitions to the uranium M levels.

  20. Uranium conversion; Urankonvertering

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

    2006-03-15

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

  1. Intracellular pH-determination by fluorescence measurements.

    Science.gov (United States)

    Visser, J W; Jongeling, A A; Tanke, H J

    1979-01-01

    A method was developed to determine the intracellular pH (pHi) of individual cells by use of fluorescence measurements. The method is based on the observation that the fluorescence excitation spectrum of fluorescein is pH-dependent. Fluorescence excitation spectra from individual rat bone marrow cells treated with fluorescein diacetate (FDA) were compared with those of fluorescein solutions of known pH values. Cells which were suspended in media of pH between 4.0 and 8.1 with high to normal buffering capacities had pHi values equal to those of the media. Cells suspended in media with low buffering capacities maintained a pH,i of 6.7 +/- 0.2. Preliminary results indicated that the pHi of individual cells may also be determined by using flow cytometry.

  2. Determination of Trace Plutonium in Uranium Product by ID-ICP-MS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Plutonium is strictly limited in the uranium product of spent fuel reprocessing. The analysis of plutonium in uranium product is the key point of product quality control. Plutonium concentration is limited below

  3. Determination of thorium, uranium and potassium elemental concentrations in surface soils in Cyprus.

    Science.gov (United States)

    Tzortzis, Michalis; Tsertos, Haralabos

    2004-01-01

    A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution gamma-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of the study area. The soil samples were air-dried, sieved through a fine mesh, sealed in 1000-ml plastic Marinelli beakers, and measured in the laboratory in terms of their gamma radioactivity for a counting time of 18 h each. From the measured gamma-ray spectra, elemental concentrations were determined for thorium (range from 2.5 x 10(-3) to 9.8 microg g(-1)), uranium (from 8.1 x 10(-4) to 3.2 microg g(-1)) and potassium (from 1.3 x 10(-4) to 1.9%). The arithmetic mean values (A.M. +/- S.D.) calculated from all samples are: (1.2+/-1.7 microg g(-1)), (0.6+/-0.7) microg g(-1), and (0.4+/-0.3%), for thorium, uranium and potassium, respectively, which are by a factor of three-six lower than the world average values of 7.4 microg g(-1) (Th), 2.8 microg g(-1) (U) and 1.3% (K) derived from all data available worldwide. The best-fitting relation between the concentrations of Th and K versus U and also of K versus Th, is essentially of linear type with a correlation coefficient of 0.93, 0.84 and 0.90, respectively. The Th/U, K/U and K/Th ratios (slopes) extracted are equal to 2.0, 2.8 x 10(3) and 1.4 x 10(3), respectively.

  4. Determination of Depleted Uranium in Environmental Bio-monitor Samples and Soil from Target sites in Western Balkan Region

    Science.gov (United States)

    Sahoo, Sarata K.; Enomoto, Hiroko; Tokonami, Shinji; Ishikawa, Tetsuo; Ujić, Predrag; Čeliković, Igor; Žunić, Zora S.

    2008-08-01

    Lichen and Moss are widely used to assess the atmospheric pollution by heavy metals and radionuclides. In this paper, we report results of uranium and its isotope ratios using mass spectrometric measurements (followed by chemical separation procedure) for mosses, lichens and soil samples from a depleted uranium (DU) target site in western Balkan region. Samples were collected in 2003 from Han Pijesak (Republika Srpska in Bosnia and Hercegovina). Inductively coupled plasma mass spectrometry (ICP-MS) measurements show the presence of high concentration of uranium in some samples. Concentration of uranium in moss samples ranged from 5.2-755.43 Bq/Kg. We have determined 235U/238U isotope ratio using thermal ionization mass spectrometry (TIMS) from the samples with high uranium content and the ratios are in the range of 0.002097-0.002380. TIMS measurement confirms presence of DU in some samples. However, we have not noticed any traces of DU in samples containing lesser amount of uranium or from any samples from the living environment of same area.

  5. Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

  6. Uranium self-diffusion in uranium monocarbide; Determination du coefficient d'autodiffusion de l'uranium dans son monocarbure

    Energy Technology Data Exchange (ETDEWEB)

    Villaine, P. [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1967-10-01

    Uranium self diffusion in near-stoichiometric stabilized uranium monocarbide has been investigated in the temperature range 1450-2000 deg. C. A thin layer of {sup 235}UC was deposited onto the samples and the diffusion profiles were analyzed by both sectioning and alpha-spectrometry techniques. The variation with temperature of the self-diffusion coefficient can be expressed by the equation: D = 7.5 x 10{sup -5} exp [-(81 {+-} 10) kcal/mole / RT] Cm{sup 2} s{sup -1} The coefficient D decreases with increasing carbon content. Autoradiographs and profile analysis have evidenced a preferential grain-boundary diffusion at all temperatures and compositions investigated. This phenomenon was used for a study of grain-boundary migration and for the evaluation of grain-boundary diffusion coefficients. The activation energy thus derived is close to the volume diffusion activation energy. (author) [French] L'autodiffusion de l'uranium dans le monocarbure d'uranium de composition voisine de la stoechiometrie et stabilise par recuit prealable, a ete etudiee entre 1450 et 2000 deg. C par la methode du depot mince de traceur, suivie des techniques d'abrasion comptage et de spectrometrie alpha. La variation avec la temperature du coefficient d'autodiffusion peut s'ecrire: D = 7.5 x 10{sup -5} exp [-(81 {+-} 10) kcal/mole / RT] Cm{sup 2} s{sup -1} Le coefficient D decroit avec une augmentation de la teneur en carbone. L'observation d'autoradiographies et l'analyse de profils de diffusion ont mis en evidence l'importance d'une diffusion intergranulaire preferentielle pour toutes les compositions etudiees et a toutes les temperatures. Cette diffusion a egalement ete utilisee pour l'etude de la migration des joints de grains et pour le calcul approche du coefficient de diffusion mtergranulaire. L'energie d'activation ainsi determinee est voisine de celle correspondant a la diffusion volumique. (auteur)

  7. Fluorescence lifetime measurements of boronate derivatives to determine glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Gable, J H

    2000-06-01

    -(Methylaminomethyl)-anthracene (MAMA), and N-benzyl-N-methyl-N-methyl anthracene (AB-B). Fluorescence lifetime measurements confirmed the two species of AB, with and without PET. Fluorescence lifetimes were approximately 11 nsec without PET and 3 nsec with PET. The degree of the interaction between the N and the B atoms was also determined by fluorescence lifetime measurements. Electron transfer rates of AB were measured to be on the order of 10{sup 8} sec{sup -1}. Analysis of AB as a glucose sensor shows it has the potential for measuring glucose concentrations in solution with less than 5% error. Two novel glucose sensing molecules, Chloro-oxazone boronate (COB) and Napthyl-imide boronate (NIB), were synthesized. Both molecules have a N{yields}B dative bond similar to AB, but with longer wavelength fluorophores. COB and NIB were found to be unacceptable for use as glucose sensor molecules due to the small changes in average fluorescence lifetime.

  8. Determination of amantadine and rimantadine using a sensitive fluorescent probe

    Science.gov (United States)

    Wang, Guang-Quan; Qin, Yan-Fang; Du, Li-Ming; Li, Jun-Fei; Jing, Xu; Chang, Yin-Xia; Wu, Hao

    2012-12-01

    Amantadine hydrochloride (AMA) and rimantadine hydrochloride (RIM) are non-fluorescent in aqueous solutions. This property makes their determination through direct fluorescent method difficult. The competing reactions and the supramolecular interaction mechanisms between the two drugs and coptisine (COP) as they fight for occupancy of the cucurbit[7]uril (CB[7]) cavity, were studied using spectrofluorimetry, 1H NMR, and molecular modeling calculations. Based on the significant quenching of the supramolecular complex fluorescence intensity, a fluorescent probe method of high sensitivity and selectivity was developed to determine AMA or RIM in their pharmaceutical dosage forms and in urine samples with good precision and accuracy. The linear range of the method was from 0.0040 to 1.0 μg mL-1 with a detection limit ranging from 0.0012 to 0.0013 μg mL-1. This shows that the proposed method has promising potential for therapeutic monitoring and pharmacokinetics and for clinical application.

  9. Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments

    Science.gov (United States)

    Stoliker, Deborah L.; Campbell, Kate M.; Fox, Patricia M.; Singer, David M.; Kaviani, Nazila; Carey, Minna; Peck, Nicole E.; Barger, John R.; Kent, Douglas B.; Davis, James A.

    2013-01-01

    Extraction techniques utilizing high pH and (bi)carbonate concentrations were evaluated for their efficacy in determining the oxidation state of uranium (U) in reduced sediments collected from Rifle, CO. Differences in dissolved concentrations between oxic and anoxic extractions have been proposed as a means to quantify the U(VI) and U(IV) content of sediments. An additional step was added to anoxic extractions using a strong anion exchange resin to separate dissolved U(IV) and U(VI). X-ray spectroscopy showed that U(IV) in the sediments was present as polymerized precipitates similar to uraninite and/or less ordered U(IV), referred to as non-uraninite U(IV) species associated with biomass (NUSAB). Extractions of sediment containing both uraninite and NUSAB displayed higher dissolved uranium concentrations under oxic than anoxic conditions while extractions of sediment dominated by NUSAB resulted in identical dissolved U concentrations. Dissolved U(IV) was rapidly oxidized under anoxic conditions in all experiments. Uraninite reacted minimally under anoxic conditions but thermodynamic calculations show that its propensity to oxidize is sensitive to solution chemistry and sediment mineralogy. A universal method for quantification of U(IV) and U(VI) in sediments has not yet been developed but the chemical extractions, when combined with solid-phase characterization, have a narrow range of applicability for sediments without U(VI).

  10. Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments.

    Science.gov (United States)

    Stoliker, Deborah L; Campbell, Kate M; Fox, Patricia M; Singer, David M; Kaviani, Nazila; Carey, Minna; Peck, Nicole E; Bargar, John R; Kent, Douglas B; Davis, James A

    2013-08-20

    Extraction techniques utilizing high pH and (bi)carbonate concentrations were evaluated for their efficacy in determining the oxidation state of uranium (U) in reduced sediments collected from Rifle, CO. Differences in dissolved concentrations between oxic and anoxic extractions have been proposed as a means to quantify the U(VI) and U(IV) content of sediments. An additional step was added to anoxic extractions using a strong anion exchange resin to separate dissolved U(IV) and U(VI). X-ray spectroscopy showed that U(IV) in the sediments was present as polymerized precipitates similar to uraninite and/or less ordered U(IV), referred to as non-uraninite U(IV) species associated with biomass (NUSAB). Extractions of sediment containing both uraninite and NUSAB displayed higher dissolved uranium concentrations under oxic than anoxic conditions while extractions of sediment dominated by NUSAB resulted in identical dissolved U concentrations. Dissolved U(IV) was rapidly oxidized under anoxic conditions in all experiments. Uraninite reacted minimally under anoxic conditions but thermodynamic calculations show that its propensity to oxidize is sensitive to solution chemistry and sediment mineralogy. A universal method for quantification of U(IV) and U(VI) in sediments has not yet been developed but the chemical extractions, when combined with solid-phase characterization, have a narrow range of applicability for sediments without U(VI).

  11. Study Progress of On-line Monitoring Device for Uranium and Plutonium by XRF

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    An X-ray fluorescence spectrometer was designed and set up, which was used to determine uranium and plutonium on-line in reprocessing process stream. Uranium in aqueous and organic phase, plutonium in aqueous were measured by using the device,

  12. Determination of trace amounts of nitrogen in uranium based samples by ion chromatography (IC) without Kjeldahl distillation.

    Science.gov (United States)

    Verma, Poonam; Rastogi, Ramakant K; Ramakumar, Karanam L

    2007-07-23

    A simple, sensitive and fast ion chromatographic (IC) method with suppressed conductivity detection is described for the determination of traces of nitrogen in uranium based fuel materials. Initially a method was developed to determine nitrogen as NH4(+) using cation exchange column after matrix separation by Kjeldahl distillation. The method was then improved by eliminating this distillation. Matrix separation after sample dissolution was done by hydrolyzing and filtering off the polyvalent cations. This had helped in reducing both the sample size and analysis time. Optimization of dissolution conditions for various kinds of uranium based samples was done to keep acid content minimum; a prerequisite chromatographic condition. The calibration plot for nitrogen was linear in the concentration range of 0.02-1 mg L(-1) with regression coefficient of 0.9999. The relative standard deviation (R.S.D.) obtained in this method (100 microL injected) was 3% and 2% in 9 replicates at nitrogen level of 28 and 55 ng g(-1), respectively. Detection limit based on S/N=3 (100 microL injected) as well as three times of variation in blank value was 4 ng g(-1). The developed method was authenticated by comparison with certified uranium-alloy standard as well as with independent indophenol photometry method. The developed method was applied to uranium-alloy, uranium-metal, sintered UO2 pellets and sintered UO2 microspheres samples.

  13. Determination of antioxidant content in biodiesel by fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Keurison F.; Caires, Anderson R.L. [Universidade Federal da Grande Dourados, MS (Brazil). Grupo de Optica Aplicada; Oliveira, Samuel L. [Universidade Federal de Mato Grosso do Sul (UFMS), MS (Brazil). Grupo de Optica e Fotonica

    2011-07-01

    Full text. Biodiesel is an alternative fuel composed by mono-alkyl esters obtained from vegetable oils or animal fats. Due to its chemical structure, biodiesel is highly susceptible to oxidation which leads to formation of insoluble gums and sediments that can block the filter system of fuel injection. Biodiesel made from vegetable oils typically has a small amount of natural antioxidants so that it is necessary to add synthetic antioxidants to enhance its stability and retain their properties for a longer period. The main antioxidants are synthetic phenolic compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) as well as natural antioxidants as tocopherols. The fluorescence spectroscopy has been applied for determination of phenolic compounds in oils. Here, a method based on fluorescence is proposed to quantify the BHA and TBHQ antioxidant concentration in biodiesel produced from sunflower and soybean oils. Soybean and sunflower biodiesel were obtained by transesterification of fatty alcohol in the presence of NaOH as catalyst. The reactions were carried out in the molar ratio of 6:1 methanol/oil. After the production and purification, biodiesel samples were stored. Biodiesel samples with BHA and TBHQ concentrations from 1000 to 8000 ppm (m/m) were pre- pared. These samples were diluted in ethanol (95%) in order to measure the fluorescence spectra. Fluorescence and excitation spectra of the solutions were recorded at room temperature using a spectrofluorimeter. The emission spectra were obtained under excitation at about 310nm and fluorescence in the 320-800nm range was evaluated. Biodiesel samples without BHA and TBHQ showed fluorescence band at about 420nm, which can be attributed to tocopherols inherent to the vegetable oils used in the biodiesel production. The addition of BHA and/or TBHQ is responsible for the appearance of a fluorescence band around 330nm. It was verified that the fluorescence

  14. Solid phase extraction and preconcentration of uranium(VI) and thorium(IV) on Duolite XAD761 prior to their inductively coupled plasma mass spectrometric determination.

    Science.gov (United States)

    Aydin, Funda Armagan; Soylak, Mustafa

    2007-04-15

    A simple and effective method is presented for the separation and preconcentration of thorium(IV) and uranium(VI) by solid phase extraction on Duolite XAD761 adsorption resin. Thorium(IV) and uranium(VI) 9-phenyl-3-fluorone chelates are formed and adsorbed onto the Duolite XAD761. Thorium(IV) and uranium(VI) are quantitatively eluted with 2molL(-1) HCl and determined by inductively coupled plasma-mass spectrometry (ICP-MS). The influences of analytical parameters including pH, amount of reagents, amount of Duolite XAD761 and sample volume, etc. were investigated on the recovery of analyte ions. The interference of a large number of anions and cations has been studied and the optimized conditions developed have been utilized for the trace determination of uranium and thorium. A preconcentration factor of 30 for uranium and thorium was achieved. The relative standard deviation (N=10) was 2.3% for uranium and 4.5% for thorium ions for 10 replicate determinations in the solution containing 0.5mug of uranium and thorium. The three sigma detection limits (N=15) for thorium(IV) and uranium(VI) ions were found to be 4.5 and 6.3ngL(-1), respectively. The developed solid phase extraction method was successively utilized for the determination of traces thorium(IV) and uranium(VI) in environmental samples by ICP-MS.

  15. Spatially resolved analyses of uranium species using a coupled system made up of confocal laser-scanning microscopy (CLSM) and laser induced fluorescence spectroscopy (LIFS); Ortsaufgeloeste Analyse von Uranspezies mittels einem Gekoppelten System aus Konfokaler Laser-Scanning Mikroskopie (CLSM) und Laser Induzierter Fluoreszenzspektroskopie (LIFS)

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, S. [Verein fuer Kernverfahrenstechnik und Analytik Rossendorf e.V. (VKTA), Dresden (Germany); Grossmann, K.; Arnold, T. [Helmholtz-Zentrum Dresden-Rossendorf e.V. (Germany). Inst. fuer Ressourcenoekologie

    2014-01-15

    The fluorescent properties of uranium when excited by UV light are used increasingly for spectroscope analyses of uranium species within watery samples. Here, alongside the fluorescent properties of the hexavalent oxidation phases, the tetra and pentavalent oxidation phases also play an increasingly important role. The detection of fluorescent emission spectrums on solid and biological samples using (time-resolved) laser induced fluorescence spectroscopy (TRLFS or LIFS respectively) has, however, the disadvantage that no statements regarding the spatial localisation of the uranium can be made. However, particularly in complex, biological samples, such statements on the localisation of the uranium enrichment in the sample are desired, in order to e.g. be able to distinguish between intra and extra-cellular uranium bonds. The fluorescent properties of uranium (VI) compounds and minerals can also be used to detect their localisation within complex samples. So the application of fluorescent microscopic methods represents one possibility to localise and visualise uranium precipitates and enrichments in biological samples, such as biofilms or cells. The confocal laser-scanning microscopy (CLSM) is especially well suited to this purpose. Coupling confocal laser-scanning microscopy (CLSM) with laser induced fluorescence spectroscopy (LIFS) makes it possible to localise and visualise fluorescent signals spatially and three-dimensionally, while at the same time being able to detect spatially resolved, fluorescent-spectroscopic data. This technology is characterised by relatively low detection limits from up to 1.10{sup -6} M for uranium (VI) compounds within the confocal volume. (orig.)

  16. Task Technical and Quality Assurance Plan for Determining Uranium and Plutonium Solubility in Actual Tank Waste Supernates

    Energy Technology Data Exchange (ETDEWEB)

    King, William D.

    2005-06-28

    Savannah River Site tank waste supernates contain small quantities of dissolved uranium and plutonium. Due to the large volume of supernates, significant quantities of dissolved uranium and plutonium are managed as part of waste transfers, evaporation and pretreatment at the Savannah River Site in tank farm operations, the Actinide Removal Project (ARP), and the Salt Waste Processing Facility (SWPF). Previous SRNL studies have investigated the effect of temperature and major supernate components on the solubility of uranium and plutonium. Based on these studies, equations were developed for the prediction of U and Pu solubility in tank waste supernates. The majority of the previous tests were conducted with simulated waste solutions. The current testing is intended to determine solubility in actual tank waste samples (as-received, diluted, and combinations of tank samples) as a function of composition and temperature. Results will be used to validate and build on the existing solubility equations.

  17. 78 FR 19311 - Low Enriched Uranium From France; Notice of Commission Determination to Conduct a Full Five-Year...

    Science.gov (United States)

    2013-03-29

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Low Enriched Uranium From France; Notice of Commission Determination to Conduct a Full Five-Year... in the subject five-year review pursuant to section 751(c)(5) of the Act. The Commission found that...

  18. Determination of the concentration of radionuclides in soil and water next the uranium mine of Caetite, Bahia, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Geangela M.; Souza, Susana O. [Federal University of Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. of Physics; Campos, Simara S.S. [State University of Southwest Bahia (UESB), Itapetinga, BA (Brazil). Dept. of Basic and Instrumental Studies; Gennari, Roseli F., E-mail: rgennari@dfn.if.usp.b [University of Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. of Physics. Dept. of Nuclear Physics

    2011-07-01

    The economic growing in Brazil is responsible for an urgent demand for energy. Uranium is the fuel used to generate nuclear power. Brazil has the sixth largest reserve of the uranium ore in the world and, nowadays there is only one mine under exploration (Uraniferous District of Lagoa Real - Caetite-BA). Some Non-Governmental Organizations (NGOs), such as Greenpeace, state that the explored uranium mine is dangerous and polluting, causing water contamination by uranium. So, the population would be receiving radiation doses above permissible limits. However, Industrias Nucleares do Brasil (INB) the company in charge of the complex extraction and production of yellow cake rejected these accusations. The main purpose of this work is the determination of the composition of natural radionuclides in the Uraniferous District of Lagoa Real in order to determine if the nearest population is exposed to environmental radiation. It was checked if there is water contamination due to the natural transport in the uranium mining surroundings. Soil and water samples from Caetite mine and also from nearby town were collected. Only one water sample collected had concentrations higher than the limits recommended by World Health Organization. The presence of radionuclides in soil samples is considered independent of mineral exploration. The effective dose rates in almost all samples are above the world average which is 2.4 mSv/y. To sum up, the presence of uranium in water and soil of the tested areas is probably due to the nature of the soil and not to the exploration of mine. (author)

  19. Spectrophotometric determination of uranium using 2-(2- Thiazolylazo-p-Cresol (TAC in the presence of surfactants

    Directory of Open Access Journals (Sweden)

    Teixeira Leonardo Sena Gomes

    1999-01-01

    Full Text Available A sensitive and selective spectrophotometric method is proposed for the rapid determination of uranium using 2-(2- Thiazolylazo-p-Cresol (TAC. The reaction between TAC and uranium (VI is instantaneous at pH 6.5 and the absorbance remains stable for over 3 h. N-cetyl-N,N,N-trimethylamonium bromide (CTAB and triton X-100 are used for increasing the sensitivity and solubility of the system respectively. The method allows the determination of uranium in the range from 0.30 to 12.0 mug mL-1 with a molar absorptivity of 1.31 x 10(4 L mol-1 cm-1 and features a detection limit of 26 ng mL-1 at 588 nm. The selectivity of the reagent was improved by the use of (1,2-cyclohexylenedinitrilo tetraacetic acid (CyDTA as masking agent. The proposed method has been successfully applied to the determination of uranium in mine drainage waters. The precision (R.S.D. < 2% and the accuracy obtained were satisfactory.

  20. Preconcentration and determination of uranium on to polyurethane foam functionalized with salicylate

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Alvaro S.F. de; Ferreira, Elizabeth de M.M., E-mail: alvaro@ien.gov.b, E-mail: massena@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Quimica Nuclear. Servico de Analises Quimicas e Ensaios de Materiais; Cassella, Ricardo J., E-mail: cassella@vm.uff.b [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Quimica Analitica. Programa de Pos-Graduacao em Quimica

    2009-07-01

    Salicylate was covalently linking with a commercial polyurethane foam (PUF) through -N=N-group generating a stable chelating sorbent (PUFS). The synthesized sorbent was characterized by Infrared Spectrometry (IR) measurement. Good stability towards various solvents was noticed. The pH influence and equilibration shaking time adsorption onto foam functionalized was studied as factors influencing the extraction process of the uranium ion solution. Extraction of uranium was accomplished in 10 minutes. Uranium at ppb level was absorbed as the salicylate complex on powered PUFS at pH about 8.0. Uranium could be achieved in 85 % from a 500 mL uranium solution (0.1 mugmL{sup -1}) which shows the suitability of salicylate foam for preconcentration analysis. (author)

  1. A rapid method for determination of the isotopic composition of uranium samples by alpha spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Martin Sanchez, A.; Tome, F.V.; Diaz Bejarano, J.; Jurado Vargas, M. (Dept. de Fisica, Univ. Extremadura, Badajoz (Spain))

    1992-03-01

    A simple method of analyzing alpha spectra from natural and enriched or depleted uranium samples is developed. The procedure is non-iterative, and takes into consideration low-energy tail and branching-ratio corrections to accurately calculate the area corresponding to each uranium isotope ({sup 234}U, {sup 235}U, {sup 236}U, {sup 238}U) in the spectrum, and then the isotopic composition of the sample. A BASIC computer program, called ENURA, has been developed to perform all the necessary calculations to give the results together with their uncertainties. Several samples were prepared with different uranium concentrations made from standard solutions with known compositions, and the method was checked against the experimental measurements from these samples. Other series of uranium spectra were theoretically constructed using a given line shape in order to cover the required range of enriched or depleted uranium. (orig.).

  2. Separating Hazardous Aerosols from Ambient Aerosols: Role of Fluorescence-Spectral Determination, Aerodynamic Deflector and Pulse Aerodynamic Localizer (PAL)

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yong-Le; Cobler, Patrick J.; Rhodes, Scott A.; Halverson, Justin; Chang, Richard K.

    2005-08-22

    An aerosol deflection technique based on the single-shot UV-laser-induced fluorescence spectrum from a flowing particle is presented as a possible front-end bio-aerosol/hazardous-aerosol sensor/identifier. Cued by the fluorescence spectra, individual flowing bio-aerosol particles (1-10 {micro}m in diameter) have been successfully deflected from a stream of ambient aerosols. The electronics needed to compare the fluorescence spectrum of a particular particle with that of a pre-determined fluorescence spectrum are presented in some detail. The deflected particles, with and without going through a funnel for pulse aerodynamic localization (PAL), were collected onto a substrate for further analyses. To demonstrate how hazardous materials can be deflected, TbCl{sub 3} {center_dot} 6H{sub 2}O (a simulant material for some chemical forms of Uranium Oxide) aerosol particles (2 {micro}m in diameter) mixed with Arizona road dust was separated and deflected with our system.

  3. Determination of beryllium by using X-ray fluorescence spectrometry.

    Science.gov (United States)

    Zawisza, Beata

    2008-03-01

    X-ray fluorescence spectrometry method is subject to certain difficulties and inconveniences for the elements having the atomic number 9 or less. These difficulties become progressively more severe as the atomic number decreases, and are quite serious for beryllium, which is practically indeterminable directly by XRF. Therefore, an indirect determination of beryllium that is based on the evaluation of cobalt in the precipitate is taken into consideration. In the thesis below, there is a description of a new, simple, and precise method by selective precipitation using hexamminecobalt(III) chloride and ammonium carbonate-EDTA solution as a complexing agent for the determining of a trace amount of beryllium using X-ray fluorescence spectrometry. The optimum conditions for [Co(NH(3))(6)][Be(2)(OH)(3)(CO(3))(2)(H(2)O)(2)].(3)H(2)O complex formation were studied. The complex was collected on the membrane filter, and the Co Kalpha line was measured by XRF. The method presents the advantages of the sample preparation and the elimination of the matrix effects due to the thin film obtained. The detection limit of the proposed method is 0.2 mg of beryllium. The method was successfully applied to beryllium determination in copper/ beryllium/cobalt alloys.

  4. Simultaneous determination of trace uranium(VI) and zinc(II) by adsorptive cathodic stripping voltammetry with aluminon ligand.

    Science.gov (United States)

    Cha, K W; Park, C I; Park, S H

    2000-09-05

    Uranium(VI) complexed with aluminon (3-[bis(3-carboxy-4-hydroxy-phenyl)methylene]-6-oxo-1,4-cyclohexadiene-1-carboxylic acid triammonium salt) was determined by adsorptive cathodic stripping voltammetry (ACSV) using a hanging mercury drop electrode. Trace uranium(VI) and zinc(II) can be simultaneously determined in a single scan in the presence of aluminon and urea. Optimal conditions were found to be: accumulation time; 180-200 s, accumulation potential; 50 mV versus Ag/AgCl, scan rate; 40 mV s(-1), supporting electrolyte; 0.1 M sodium acetate buffer at pH 6.5-7.0, and concentration of aluminon; 1x10(-6) M. The linear range of uranium(VI) and zinc(II) were observed over the concentration range 2-33 and 30-120 ng ml(-1), respectively. The detection limit (S/N=3) are 0.2 ng ml(-1) (uranium) and 30 ng ml(-1) (zinc). A good reproducibility shows RSDs of 2.5-4.0% (n=10). The procedure offers high selectivity, with the presence of urea masking some metal ions.

  5. A selective electromembrane extraction of uranium (VI) prior to its fluorometric determination in water.

    Science.gov (United States)

    Davarani, Saied Saeed Hosseiny; Moazami, Hamid Reza; Keshtkar, Ali Reza; Banitaba, Mohammad Hossein; Nojavan, Saeed

    2013-06-14

    A novel method for the selective electromembrane extraction (EME) of U(6+) prior to fluorometric determination has been proposed. The effect of extraction conditions including supported liquid membrane (SLM) composition, extraction time and extraction voltage were investigated. An SLM composition of 1% di-2-ethyl hexyl phosphonic acid in nitrophenyl octyl ether (NPOE) showed good selectivity, recovery and enrichment factor. The best performance was achieved at an extraction potential of 80 volts and an extraction time of 14 minutes Under the optimized conditions, a linear range from 1 to 1000 ng mL(-1) and LOD of 0.1 ng mL(-1) were obtained for the determination of U(6+). The EME method showed good performance in sample cleanup and the reduction of the interfering effects of Mn(2+), Zn(2+), Cd(2+), Ni(2+), Fe(3+), Co(2+), Cu(2+), Cl(-) and PO4(3-) ions during fluorometric determination of uranium in real water samples. The recoveries above 54% and enrichment factors above 64.7 were obtained by the proposed method for real sample analysis.

  6. Determination of laser-evaporated uranium dioxide by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Allred, R.

    1987-05-01

    Safety analyses of nuclear reactors require information about the loss of fuel which may occur at high temperatures. In this study, the surface of a uranium dioxide target was heated rapidly by a laser. The uranium surface was vaporized into a vacuum. The uranium bearing species condensed on a graphite disk placed in the pathway of the expanding uranium vapor. Scanning electron microscopy and X-ray analysis showed very little droplet ejection directly from the laser target surface. Neutron activation analysis was used to measure the amount of uranium deposited. The surface temperature was measured by a fast-response automatic optical pyrometer. The maximum surface temperature ranged from 2400 to 3700/sup 0/K. The Hertz-Langmuir formula, in conjunction with the measured surface temperature transient, was used to calculate the theoretical amount of uranium deposited. There was good agreement between theory and experiment above the melting point of 3120/sup 0/K. Below the melting point much more uranium was collected than was expected theoretically. This was attributed to oxidation of the surface. 29 refs., 16 figs., 7 tabs.

  7. Determination of uranium content in phosphate ores using different measurement techniques

    Directory of Open Access Journals (Sweden)

    Mohammad A. Al-Eshaikh

    2016-01-01

    Full Text Available The most important unconventional source of uranium is found in phosphate deposits; unfortunately, nowadays its exploitation is limited by economic constraints. The uranium concentrations in phosphate ores in the world vary regionally and most countries with large phosphate deposits have either plant in operation to extract uranium or are at the stage of pilot extraction plants. The aim of this investigation is to evaluate uranium content in the Saudi phosphate ores for, at least, two reasons: firstly, upgrading the phosphate quality by removing the uranium content in order to reduce the radioactivity in the fertilizer products. Secondly, getting benefit from the extracted uranium for its domestic use as a fuel in nuclear power and desalination plants. The results of this study show that the uranium concentration in Saudi phosphate rocks is relatively low (less than 100 ppm, which is not economically encouraging for its direct extraction. However, its extraction as a byproduct from the phosphoric acid, which will have higher concentration could be quite promising and worth exploiting.

  8. Comparison of three techniques for the determination of uranium and thorium in rocks

    Science.gov (United States)

    Hart, R.J.; Reid, D.L.; Stuckless, J.S.; Welke, H.J.

    1980-01-01

    U and Th concentrations have been determined in a series of selected whole-rock samples, using three different techniques: neutron activation analysis (INAA), X-ray fluorescence spectrometry (XRF) and isotope dilution mass spectrometry (ID). The INAA technique yields U and Th data that are comparable with those obtained by ID over the entire concentration range studied. XRF only provides data with comparable precision at relatively high concentrations (> 10 ppm) but has the advantage of being able to determine other useful elements such as Rb, Sr, Pb and K. The choice between INAA and XRF therefore depends on the concentration levels anticipated, together with the overall requirements for the particular study. ?? 1980.

  9. Spectrophotometric determination of trace amounts of uranium(VI) in water samples after mixed micelle-mediated extraction.

    Science.gov (United States)

    Madrakian, Tayyebeh; Afkhami, Abbas; Mousavi, Afrouz

    2007-02-15

    A cloud point extraction process using mixed micelle of the cationic surfactant CTAB and non-ionic surfactant TritonX-114 to extract uranium(VI) from aqueous solutions was investigated. The method is based on the color reaction of uranium with pyrocatechol violet in the presence of potassium iodide in hexamethylenetetramine buffer media and mixed micelle-mediated extraction of complex. The optimal extraction and reaction conditions (e.g. surfactant concentration, reagent concentration, effect of time) were studied and the analytical characteristics of the method (e.g. limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 0.20-10.00ng mL(-1) of uranium(VI) ion and the detection limit of the method is 0.06ng mL(-1). The interference effect of some anions and cations was also tested. The method was applied to the determination of uranium(VI) in tap water, waste-water and well water samples.

  10. [Study on solid phase extraction and spectrophotometric determination of uranium in water with 2-(2-quinolylazo)-5-dimthylaminophenol].

    Science.gov (United States)

    Wang, Liang; Yuan, Zhuo-Bin; Hu, Qiu-Fen; Yang, Guang-Yu; Yin, Jia-Yuan

    2005-05-01

    A new chromogenic reagent 2-(2-quinolylazo)-5-Dimthylaminophenol (QADMAP) was synthesized, and its structure was verified by elemental analysis, infrared spectrum, 1H nuclear magnetic resonance spectrum, mass spectrumand UV-spectrum. The color reaction of QADMAP with uranium was studied. In the presence of pH 7.8 buffer solution, when fluorin ion and TritonX-100 medium exist, QADMAP can react with uranium and fluorin to form a stable 1 : 1 : 1 stable complex [F- :QADMAP : U(VI)]. The molar absorptivity is 1.05 x 10(5) L x mol(-1) x cm(-1) at 590 nm. Beer's law is obeyed in range of 0-20 microg/10 mL. The uranium in samples can be enriched and separated by solid phase extraction with TBP resin cartridge. This method is applied to the determination of uranium in water sample. The relative standard deviations are 2.2%-3.6%, and the recoveries are 94%-105%.

  11. Optimization of Davies and Gray/NBL method used for determination of total uranium concentration in the safeguards destructive analysis

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Wanderley S. da; Viana, Aline Gonzalez; Barros, Pedro Dionisio de; Cristiano, Barbara Fernandes G., E-mail: wanderley@ird.gov.br, E-mail: agonzalez@ird.gov.br, E-mail: pedrodio@ird.gov.br, E-mail: barbara@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    One important activity conducted by the Brazilian State System of Accounting for and Control of Nuclear Materials - SSAC is to verify inventories of the nuclear facilities by nondestructive analysis and destructive analysis. For destructive analysis, the Safeguards Laboratory of Brazilian Nuclear Energy Commission - LASAL/CNEN has been applying the 'Davies and Gray/NBL' method in samples taken during inspections at nuclear facilities since 1984 in Brazil and Argentina. This method consists of the determination of total uranium concentration by potentiometric titration of uranium (IV) with a standard solution of potassium dichromate as oxidizing agent. This solution is prepared using a K{sub 2}Cr{sub 2}O{sub 7} SRM 136e standard reference material (99.984 ±0.010) wt% certified by National Institute of Standard and Technology - NIST. The procedure also includes the calibration with primary uranium standards reference material (NBL CRM 112A). In order to reduce the consumption of K{sub 2}Cr{sub 2}O{sub 7} and the other reagent involved in the procedure, without any loss in the performance of the method, a K{sub 2}Cr{sub 2}O{sub 7} solution with half the regular concentration was prepared and used to test the uranium concentration in several aliquots with a content between 30 mg to 40 mg of uranium per gram of solution. After optimizing the parameters and procedure, it was possible to get the same performance as well. As a consequence, decreasing of the cost, the amount of waste and also a reduction in the titration time of each aliquot was achieved. Thus, this work describes all details in this research as well as the results and its evaluation. (author)

  12. A selective electromembrane extraction of uranium (VI) prior to its fluorometric determination in water

    Energy Technology Data Exchange (ETDEWEB)

    Davarani, Saied Saeed Hosseiny, E-mail: ss-hosseiny@sbu.ac.ir [Faculty of Chemistry, Shahid Beheshti University, G. C., 1983963113, Evin, Tehran (Iran, Islamic Republic of); Moazami, Hamid Reza [Faculty of Chemistry, Shahid Beheshti University, G. C., 1983963113, Evin, Tehran (Iran, Islamic Republic of); Keshtkar, Ali Reza [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Banitaba, Mohammad Hossein; Nojavan, Saeed [Faculty of Chemistry, Shahid Beheshti University, G. C., 1983963113, Evin, Tehran (Iran, Islamic Republic of)

    2013-06-14

    Graphical abstract: -- Highlights: •A method for fast and selective extraction of U{sup 6+} prior to fluorometric analysis. •Sample clean-up of U{sup 6+} water samples was done by electromembrane extraction (EME). •EME eliminated interfering effects of Zn{sup 2+}, Cd{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Cu{sup 2+} and Cl{sup −} ions. •EME reduced interfering effects of Mn{sup 2+}, Fe{sup 3+} and PO{sub 4}{sup 3−}, considerably. -- Abstract: A novel method for the selective electromembrane extraction (EME) of U{sup 6+} prior to fluorometric determination has been proposed. The effect of extraction conditions including supported liquid membrane (SLM) composition, extraction time and extraction voltage were investigated. An SLM composition of 1% di-2-ethyl hexyl phosphonic acid in nitrophenyl octyl ether (NPOE) showed good selectivity, recovery and enrichment factor. The best performance was achieved at an extraction potential of 80 volts and an extraction time of 14 minutes Under the optimized conditions, a linear range from 1 to 1000 ng mL{sup −1} and LOD of 0.1 ng mL{sup −1} were obtained for the determination of U{sup 6+}. The EME method showed good performance in sample cleanup and the reduction of the interfering effects of Mn{sup 2+}, Zn{sup 2+}, Cd{sup 2+}, Ni{sup 2+}, Fe{sup 3+}, Co{sup 2+}, Cu{sup 2+}, Cl{sup −} and PO{sub 4}{sup 3−} ions during fluorometric determination of uranium in real water samples. The recoveries above 54% and enrichment factors above 64.7 were obtained by the proposed method for real sample analysis.

  13. Determination of thorium by fluorescent x-ray spectrometry

    Science.gov (United States)

    Adler, I.; Axelrod, J.M.

    1955-01-01

    A fluorescent x-ray spectrographic method for the determination of thoria in rock samples uses thallium as an internal standard. Measurements are made with a two-channel spectrometer equipped with quartz (d = 1.817 A.) analyzing crystals. Particle-size effects are minimized by grinding the sample components with a mixture of silicon carbide and aluminum and then briquetting. Analyses of 17 samples showed that for the 16 samples containing over 0.7% thoria the average error, based on chemical results, is 4.7% and the maximum error, 9.5%. Because of limitations of instrumentation, 0.2% thoria is considered the lower limit of detection. An analysis can be made in about an hour.

  14. Quantification and isotope ratio determination of uranium in particles of environmental samples using isotope dilution thermal ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Choi, Eun-Ju [Chungnam National University, Daejeon (Korea, Republic of)

    2015-10-15

    Highly accurate and precise quantitative and qualitative analysis of nuclear materials in environmental samples plays essential roles in monitoring undeclared nuclear activities of corresponding facilities. The former focuses on the quantification of uranium (U) and plutonium (Pu) contained in a whole sample, while the latter enables us to acquire the isotopic ratios, which serve as the crucial basis to trace the nuclear histories of a facility. However, the quantity of nuclear materials in a single-particle has not been acquired from the particle analysis, but has been estimated by the size of the particles. This report is to describe the method developed to determine the quantity and the isotopic ratios of uranium in a micro-particle simultaneously. Complete dissolution of particle-spike mixture by repeated addition of nitric acid on a rhenium filament was performed to ensure the homogeneity of the mixture. Thermal ionization mass spectrometry (TIMS) was utilized to measure the U isotope ratios of the mixture with high accuracy. The isotopic ratios of the uranium in the particle sample were determined by mathematical deconvolution of U isotopic ratios of the mixture. Verification using particles of a certified reference material showed that the newly developed method can be used to quantify and to determine the isotopic ratios of U in a particle simultaneously. The development of a method for simultaneous determination of the quantity and the isotope ratios of uranium contained in particles by isotope dilution thermal ionization mass spectrometry (ID-TIMS) was described. For homogeneity of the mixture of particles and spike, repeated dissolution using nitric acid for five times was performed.

  15. Spectrographic determination of boron and silicon in uranium tetrafluoride: Study of the chemical reactions in the electrode cavity when ZnO is used as a uranium excitation suppressor; Determinacion espectrografica de Boro y Silicio en Tetrafluoruro de Unraio: Estudio de las reacciones quimicas que tienen lugar en el crater del electrodo al autilizar ZnO como supresor de la excitacion del Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevila, C.; Rosa, M.

    1973-07-01

    A method has been developed for determining traces of boron and silicon in uranium tetrafluoride. Use is made of zinc oxide to decrease the volatilization of uranium and achieve high sensitivities. The thermochemical reactions which occur in the anode cavity during the arcing process have been investigated. UO{sub 2} and a uranium, zinc and fluorine compound, both less volatile than uranium tetrafluoride, are formed. (Author)

  16. The determination of phosphorus in uranium minerals and resulting solutions; Determinacion de fosforo en minerales de uranio y soluciones procedentes de su beneficio

    Energy Technology Data Exchange (ETDEWEB)

    Petrement Eguiluz, J. C.; Rarellada Bellod, R.; Fernandez Cellini, R.

    1964-07-01

    Interferences of several elements present in Spanish uranium minerals in the phosphorus determination by the spectrophotometrical method of the molibdovanada te phosphoric acid are studied. A method is described with a previous separation of these element by a cationic resin. This method is successfully applied to the phosphorus determination in acid or alkaline lixiviation solutions of uranium minerals, as well as in the evaluates of ion exchange resins used used technically for the concentration of solutions with a low uranium content. (Author) 11 refs.

  17. Gamma-spectrometric determination of {sup 232}U in uranium-bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Zsigrai, Jozsef [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), 76125 Karlsruhe, P.O. Box 2340 (Germany); Nguyen, Tam Cong [Centre for Energy Research of the Hungarian Academy of Sciences (EK), 1525 Budapest 114, P.O. Box 49 (Hungary); Berlizov, Andrey [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), 76125 Karlsruhe, P.O. Box 2340 (Germany)

    2015-09-15

    The {sup 232}U content of various uranium-bearing items was measured using low-background gamma spectrometry. The method is independent of the measurement geometry, sample form and chemical composition. Since {sup 232}U is an artificially produced isotope, it carries information about previous irradiation of the material, which is relevant for nuclear forensics, nuclear safeguards and for nuclear reactor operations. A correlation between the {sup 232}U content and {sup 235}U enrichment of the investigated samples has been established, which is consistent with theoretical predictions. It is also shown how the correlation of the mass ratio {sup 232}U/{sup 235}U vs. {sup 235}U content can be used to distinguish materials contaminated with reprocessed uranium from materials made of reprocessed uranium.

  18. Gamma-spectrometric determination of 232U in uranium-bearing materials

    CERN Document Server

    Zsigrai, Jozsef; Berlizov, Andriy

    2015-01-01

    The 232U content of various uranium-bearing items was measured using low-background gamma-spectrometry. The method is independent of the measurement geometry, sample form and chemical composition. Since 232U is an artificially produced isotope, it carries information about previous irradiation of the material, which is relevant for nuclear forensics, nuclear safeguards and for nuclear reactor operations. A correlation between the 232U content and 235U enrichment of the investigated samples has been established, which is consistent with theoretical predictions. It is also shown how the correlation of the mass ratio 232U/235U vs. 235U content can be used to distinguish materials contaminated with reprocessed uranium from materials made of reprocessed uranium.

  19. Radiometric Determination of Uranium in Natural Waters after Enrichment and Separation by Cation-Exchange and Liquid-Liquid Extraction

    CERN Document Server

    Pashalidis, I

    2003-01-01

    The alpha-radiometric determination of uranium after its pre-concentration from natural water samples using the cation-exchange resin Chelex-100, its selective extraction by tributylphosphate and electrodeposition on stainless steel discs is reported. The validity of the separation procedure and the chemical recoveries were checked by addition of uranium standard solution as well as by tracing with U-232. The average uranium yield was determined to be (97 +- 2) % for the cation-exchange, (95 +- 2) % for the liquid-liquid extraction, and more than 99% for the electrodeposition. Employing high-resolution alpha-spectroscopy, the measured activity of the U-238 and U-234 radioisotopes was found to be of similar magnitude; i.e. ~7 mBq/L and ~35 mBq/L for ground- and seawater samples, respectively. The energy resolution (FWHM) of the alpha-peaks was 22 keV, while the Minimum Detectable Activity (MDA) was estimated to be 1 mBq/L (at the 95% confidence limit).

  20. REIMEP-22 inter-laboratory comparison. ''U Age Dating - determination of the production date of a uranium certified test sample''

    Energy Technology Data Exchange (ETDEWEB)

    Venchiarutti, Celia; Richter, Stephan; Jakopic, Rozle; Aregbe, Yetunde [European Commission, Joint Research Centre (JRC), Geel (Belgium). Institute for Reference Materials and Measurements (IRMM); Varga, Zsolt; Mayer, Klaus [European Commission, Joint Research Centre (JRC), Karlsruhe (Germany). Institute for Transuranium Elements (ITU)

    2015-07-01

    The REIMEP-22 inter-laboratory comparison aimed at determining the production date of a uranium certified test sample (i.e. the last chemical separation date of the material). Participants in REIMEP-22 on ''U Age Dating - Determination of the production date of a uranium certified test sample'' received one low-enriched 20 mg uranium sample for mass spectrometry measurements and/or one 50 mg uranium sample for a-spectrometry measurements, with an undisclosed value for the production date. They were asked to report the isotope amount ratios n({sup 230}Th)/n({sup 234}U) for the 20 mg uranium sample and/or the activity ratios A({sup 230}Th)/A({sup 234}U) for the 50 mg uranium sample in addition to the calculated production date of the certified test samples with its uncertainty. Reporting of the {sup 231}Pa/{sup 235}U ratio and the respective calculated production date was optional. Eleven laboratories reported results in REIMEP-22. Two of them reported results for both the 20 mg and 50 mg uranium certified test samples. The measurement capability of the participants was assessed against the independent REIMEP-22 reference value by means of z- and zeta-scores in compliance with ISO 13528:2005. Furthermore a performance assessment criterion for acceptable uncertainty was applied to evaluate the participants' results. In general, the REIMEP-22 participants' results were satisfactory. This confirms the analytical capabilities of laboratories to determine accurately the age of uranium materials with low amount of ingrown thorium (young certified test sample). The Joint Research Centre of the European Commission (EC-JRC) organised REIMEP-22 in parallel to the preparation and certification of a uranium reference material certified for the production date (IRMM-1000a and IRMM-1000b).

  1. Fluor determination by alkaline hydrolysis of the uranium and thorium fluorides; Determinacion de fluor por hidrolisis alcalina en fluoruros de uranio y torio

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina Gomez, L.; Gasco Sanchez, L.

    1961-07-01

    The alkaline hydrolysis of the uranium and thorium fluorides is studded and a new method for the determination of the fluoride, on the basis of a indirect volumetric titration with standard soda, is proposed. The compounds that may influence the hydrolysis of the uranium fluoride and that may be occasionally found in it as impurities are also studied. the method can be applied to the uranium fluoride except when there is a great quantity of F{sub 2}UO{sub 2} or UO{sub 3} present in the sample. (Author) 20 refs.

  2. Isotopic determination of uranium in soil by laser induced breakdown spectroscopy

    Science.gov (United States)

    Chan, George C.-Y.; Choi, Inhee; Mao, Xianglei; Zorba, Vassilia; Lam, Oanh P.; Shuh, David K.; Russo, Richard E.

    2016-08-01

    Laser-induced breakdown spectroscopy (LIBS) operated under ambient pressure has been evaluated for isotopic analysis of uranium in real-world samples such as soil, with U concentrations in the single digit percentage levels. The study addresses the requirements for spectral decomposition of 235U and 238U atomic emission peaks that are only partially resolved. Although non-linear least-square fitting algorithms are typically able to locate the optimal combination of fitting parameters that best describes the experimental spectrum even when all fitting parameters are treated as free independent variables, the analytical results of such an unconstrained free-parameter approach are ambiguous. In this work, five spectral decomposition algorithms were examined, with different known physical properties (e.g., isotopic splitting, hyperfine structure) of the spectral lines sequentially incorporated into the candidate algorithms as constraints. It was found that incorporation of such spectral-line constraints into the decomposition algorithm is essential for the best isotopic analysis. The isotopic abundance of 235U was determined from a simple two-component Lorentzian fit on the U II 424.437 nm spectral profile. For six replicate measurements, each with only fifteen laser shots, on a soil sample with U concentration at 1.1% w/w, the determined 235U isotopic abundance was (64.6 ± 4.8)%, and agreed well with the certified value of 64.4%. Another studied U line - U I 682.691 nm possesses hyperfine structure that is comparatively broad and at a significant fraction as the isotopic shift. Thus, 235U isotopic analysis with this U I line was performed with spectral decomposition involving individual hyperfine components. For the soil sample with 1.1% w/w U, the determined 235U isotopic abundance was (60.9 ± 2.0)%, which exhibited a relative bias about 6% from the certified value. The bias was attributed to the spectral resolution of our measurement system - the measured line

  3. Uranium and thorium nuclides series determined in medicinal plants commonly used in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P.; Francisconi, L.; Damatto, S. [IPEN/CNEN-SP, Sao Paulo (Brazil)

    2014-07-01

    In recent years the study of medicinal plants has become the focus of ever more extensive research all over the world due to their diversity and potential as source of medicinal products. According to the World Health Organization approximately 80% of world population makes use of medicinal herbs due to their believed therapeutic action. Besides being used as medicine, medicinal plants are also largely used as dietary supplements. The presence of radionuclides in plants constitutes one of the main pathways for their transfer to man. The amount of radioactive nuclides from U and Th series in edible vegetables are relatively well known since they have been the main concern of research conducted worldwide. Medicinal plants, on the other hand, have been neglected in these studies, possibly because the ingestion of radioactive material through their consumption has not been recognized or was considered insignificant. The objective of the present study was to determine the content of natural radionuclides from {sup 238}U and {sup 232}Th series in 25 species of medicinal plants used in Brazil, both as medicine and as dietary supplement. The medicinal plant samples were obtained in specialized pharmacies and drugstores. The raw plant and their extracts, produced as recommended by the National Agency for Sanitary Vigilance, were analyzed by Instrumental Neutron Activation Analyses for the determination of U and Th and by Total Alpha and Beta Counting after Radiochemical Separation for determination of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb. In the raw plants the activity concentrations varied from 0,08 Bq kg{sup -1} to 8,0 Bq kg{sup -1} for thorium, from < LID to 22 Bq kg{sup -1} for uranium, from 1,8 Bq kg{sup -1} to 12 Bq kg{sup -1} for {sup 226}Ra, from 33 Bq kg{sup -1} to 74 Bq kg{sup -1} for {sup 228}Ra and from 10 Bq kg{sup -1} to 120 Bq kg{sup -1} for {sup 210}Pb. In the extracts, the activity concentrations varied from 9 mBq kg{sup -1} to 137 mBq kg{sup -1} for Th

  4. Determination of uranium partition coefficients of a semi-arid soil in Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Heloisa H.F.; Pontedeiro, Elizabeth M.; Su, Jian, E-mail: heloisa@lasme.coppe.ufrj.br, E-mail: bettinadulley@hotmail.com, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Cursos de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Simulacao e Metodos de Engenharia; Dourado, Eneida R.G., E-mail: eneida@inb.gov.br [Industrias Nucleares do Brasil (INB), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    In mining and processing industries, the subsurface is one of the most vulnerable compartments to environmental contamination. Understanding the interactions between soil and contaminants is critical for predicting the possible environmental impacts caused by mining and milling operations. One of the main parameters used for this purpose is the partition (or distribution) coefficient, K{sub d}, which allows a relatively simple modeling approach by grouping various sorption phenomena into a single value. However, this parameter is strongly influenced by the physical and chemical characteristics of the medium, such as soil type, pH and solution composition. Thus, this study aims to assess the values of K{sub d} for uranium of typical soils from Bahia's semi-arid region using two different types of solute, one being a standard solution of uranyl acetate and one the liquor of uranium generated during processing. To calculate this parameter, batch adsorption experiments were carried out and adsorption isotherms (linear, Langmuir and Freundlich) were constructed using the Mathematica software. Results obtained for a single type of soil showed reduced values of K{sub d} for a liquor containing uranium when compared to values obtained with the uranyl acetate solution. This indicates that uranium from liquor is less adsorbed onto soil particles, and hence may move more quickly into the subsurface. (author)

  5. Comparison of CdTe and CdZnTe Detectors for Field Determination of Uranium Isotopic Enrichments

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, KJ

    2004-01-23

    A performance comparison of a CdTe and a CdZnTe detector when exposed to uranium samples of various isotopic enrichments has been performed. These high-resolution detectors can assist in the rapid determination of uranium isotopic content of illicit material. Spectra were recorded from these room temperature semiconductor detectors with a portable multi-channel analyzer, both in the laboratory and in a field environment. Both detectors were operated below ambient temperature using the vendor supplied thermoelectric coolers. Both detectors had nominally the same active volume (18 mm3 for the CdZnTe and 25 mm3 for the CdTe detector) and resolution. Spectra of samples of known isotopic content were recorded at fixed geometries. An evaluation of potential signature g rays for the detection of enriched uranium was completed. Operational advantages and disadvantages of each detector are discussed. There is a need to improve the detection sensitivity during the interdiction of special nuclear materials (SNM) for increased homeland protection. It is essential to provide additional tools to first responders and law enforcement personnel for assessing nuclear and radiological threats.

  6. Spectrographic determination of impurities in enriched uranium solutions; Determinacion espectrografica de impurezas en soluciones de uranio enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Capdevila, C.; Roca, M.

    1980-07-01

    A spectrographic procedure for the determination of trace amounts of Al, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, L i , Hg, Mn, Mo, Na, Nb, Ni, P, Pb, Ru, Sb, Sn, Sr, Ti, V, Zn, and Zr in enriched uranyl nitrate solutions from the reprocessing of spent nuclear fuels is described. After removal of uranium by either TBP or TNOA solvent extraction, the aqueous phase Is analysed by the graphite spark technique. TBP is adequate for all impurities, excepting boron and phosphorus; both of these elements can sat is factory be determined by using TNOA after the addition of mannitol to avoid boron losses. (Author) 4 refs.

  7. Determination of lead, uranium, thorium, and thallium in silicate glass standard materials by isotope dilution mass spectrometry

    Science.gov (United States)

    Barnes, I.L.; Garner, E.L.; Gramlich, J.W.; Moore, L.J.; Murphy, T.J.; Machlan, L.A.; Shields, W.R.; Tatsumoto, M.; Knight, R.J.

    1973-01-01

    A set of four standard glasses has been prepared which have been doped with 61 different elements at the 500-, 50-, 1-, and 0.02-ppm level. The concentrations of lead, uranium, thorium, and thallium have been determined by isotope dilution mass spectrometry at a number of points in each of the glasses. The results obtained from independent determinations in two laboratories demonstrate the homogeneity of the samples and that precision of the order of 0.5% (95% L.E.) may be obtained by the method even at the 20-ppb level for these elements. The chemical and mass spectrometric procedures necessary are presented.

  8. Method for determination of uranium isotopes in environmental samples by liquid-liquid extraction with triisooctylamine/xylene in hydrochloric media and alpha spectrometry.

    Science.gov (United States)

    Popov, L

    2012-10-01

    Alternative method for determination of uranium isotopes in various environmental samples is presented. The method is based on total decomposition of the solid materials and preconcentration of liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid-liquid extraction with triisooctylamine/xylene in hydrochloric media. After the additional removal of stable iron by extraction with diisopropyl ether, purified uranium is electrodeposited on stainless steel disks and measured by alpha spectrometry. The analytical method has been successfully applied to the determination of uranium isotopes in water and bottom sediments from the rivers Danube, Ogosta and Tzibritza in Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices.

  9. Determination of flame temperature using laser induced fluorescence (LIF)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Lina Augusta Martins Ramos da [Instituto Tecnologico de Aeronautica (ITA/DCTA), Sao Jose dos Campos, SP (Brazil); Barreta, Gilberto; Carinhana Junior, Dermeval; Toledo, Antonio Osny de [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil)

    2011-07-01

    Full text: Laser Induced Fluorescence, LIF, is one of the most used techniques in combustion diagnostics. The excitation method is based on the spontaneous spectrum from atoms or molecules that were excited by laser radiation. In general, intermediated combustion species, as OH and CH radicals, are used as temperature probes. Usually, several rotational levels are used by tuning the laser afterwards across the corresponding absorption transitions. The emission spectrum is detected in a convenient spectral range. The accuracy of measurements depends on the laser linewidth, the delay between the laser excitation and spectra detection and, mainly, the spectral interval of laser excitation. In this work, OH LIF spectra from stoichiometric LPG (Liquefied Petroleum Gas) flames were obtained using a tuned laser with a spectral range set from 282 nm up to 283 nm. This corresponds to the rotation levels of the 0-1 vibration band of OH radical. The laser energy was ca. 0.2 mJ. The emission spectrum was collected in the spectral range of the 305-310 nm, which corresponds to the region of the 0-0 band. The temperature was determined by the Boltzmann method. This is based on the measurement of the relative peak intensities of the emission spectrum. A plot of natural logarithm of line intensities versus energy level returns a straight line, whose slope is the inverse of the rotational temperature. The flame temperature was ca. 2300 K. This value is consistent with previous results obtained in our laboratory. (author)

  10. Spectrophotometric titrations: Application to the determination of some elements in uranium solutions; Les titrages spectrophotometriques: Application a la determination de quelques elements dans les solutions d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    L' Her, M. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    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) [French] Le but de ce travail est l'application des titrages spectrophotometriques a l'analyse des solutions uraniferes. Nous avons ete amenes a examiner les principes generaux de ces titrages, principes qu'il nous est apparu necessaire de rappeler. Dans une premiere partie nous traiterons donc d'une facon generale des titrages spectrophotometriques, en examinant leur principe fondamental, leur mise en oeuvre ainsi que les possibilites diverses de dosage. Nous examinerons aussi les avantages de la methode de titrage, en insistant notamment sur la possibilite de faire des dosages successifs. La possibilite d'application de ces titrages spectrophotometriques a l'analyse des solutions uraniferes sera le sujet de la deuxieme partie: nous y decrivons le dosage de quelques especes, dans les solutions d'uranium (VI). A cette deuxieme partie nous joindrons une annexe experimentale comportant une

  11. Determination of {sup 236}U and transuranium elements in depleted uranium ammunition by {alpha}-spectrometry and ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Desideri, D.; Meli, M.A.; Roselli, C.; Testa, C. [General Chemistry Institute, Urbino University, Urbino (Italy); Boulyga, S.F.; Becker, J.S. [Central Department of Analytical Chemistry, Research Centre Juelich, Juelich (Germany)

    2002-11-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ({sup 236}U, {sup 239}Pu, {sup 240}Pu, {sup 241}Am, and {sup 237}Np) in the ammunition. In this work the analysis of actinides by {alpha}-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. {sup 242}Pu and {sup 243}Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri-n-octylamine (TNOA), with a decontamination factor higher than 10{sup 6}; after elution plutonium was determined by ICP-MS ({sup 239}Pu and {sup 240}Pu) and {alpha}-spectrometry ({sup 239+240}Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10{sup -12} g g{sup -1} and 2 x 10{sup -11} g g{sup -1}. The {sup 240}Pu/{sup 239}Pu isotope ratio in one penetrator sample (0.12{+-}0.04) was significantly lower than the {sup 240}Pu/{sup 239}Pu ratios found in two soil samples from Kosovo (0.35{+-}0.10 and 0.27{+-}0.07). {sup 241}Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10{sup 7}. The concentration of {sup 241}Am in the penetrator samples was 2.7 x 10{sup -14} g g{sup -1} and <9.4 x 10{sup -15} g g{sup -1}. In addition {sup 237}Np was detected at ultratrace levels. In general, ICP-MS and {alpha}-spectrometry results were in good agreement.The presence of anthropogenic radionuclides ({sup 236}U, {sup 239}Pu,{sup 240}Pu, {sup 241}Am, and {sup 237}Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of

  12. Determination of (236)U and transuranium elements in depleted uranium ammunition by alpha-spectrometry and ICP-MS.

    Science.gov (United States)

    Desideri, D; Meli, M A; Roselli, C; Testa, C; Boulyga, S F; Becker, J S

    2002-11-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ((236)U, (239)Pu, (240)Pu, (241)Am, and (237)Np) in the ammunition. In this work the analysis of actinides by alpha-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. (242)Pu and (243)Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri- n-octylamine (TNOA), with a decontamination factor higher than 10(6); after elution plutonium was determined by ICP-MS ((239)Pu and (240)Pu) and alpha-spectrometry ((239+240)Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10(-12) g g(-1) and 2 x 10(-11) g g(-1). The (240)Pu/(239)Pu isotope ratio in one penetrator sample (0.12+/-0.04) was significantly lower than the (240)Pu/(239)Pu ratios found in two soil samples from Kosovo (0.35+/-0.10 and 0.27+/-0.07). (241)Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10(7). The concentration of (241)Am in the penetrator samples was 2.7 x 10(-14) g g(-1) and <9.4 x 10(-15) g g(-1). In addition (237)Np was detected at ultratrace levels. In general, ICP-MS and alpha-spectrometry results were in good agreement. The presence of anthropogenic radionuclides ((236)U, (239)Pu,(240)Pu, (241)Am, and (237)Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of radionuclides are very low, their radiotoxicological effect is negligible.

  13. Autoradiography of geological fluorite samples for determination of uranium and thorium distribution using nuclear track methodology

    Energy Technology Data Exchange (ETDEWEB)

    Pi, T.; Sole, J. [Instituto de Geologia, UNAM, Cd. Universitaria, Coyoacan, 04510 Mexico DF (Mexico); Golzarri, J.I; Rickards, J.; Espinosa, G. [IFUNAM, AP 20-364, 01000 Mexico DF (Mexico)]. e-mail: espinosa@fisica.unam.mx

    2007-07-01

    In this paper we present the uranium and thorium distribution analysis of several samples of the 'La Azul' an epithermal fluorspar deposit in southern Mexico, using nuclear track methodology (NTM), in the alpha-autoradiography mode, by placing the mineral sample in contact with a polycarbonate detector. This constitutes a non-destructive analysis, with sufficient sensitivity to provide valuable information about textural and para genetic characteristics of the geological samples. The selected nuclear track detector was CR-39 (Landauer). The region of interest of the geological samples was polished and put in contact with the detector material surface for 45 days in a vacuum chamber (10-3 torr). After this period of time, the detectors were chemically etched, revealing the auto radiograph of the radioactive material. The results show a clear distribution of bands of uranium and thorium in the fluorite samples. This is valuable information for the genetic or geochronological studies of the ore deposits. (Author)

  14. Micro-column solid phase extraction to determine uranium and thorium in environmental samples.

    Science.gov (United States)

    Tsai, Tsuey-Lin; Lin, Chun-Chih; Chu, Tieh-Chi

    2008-08-01

    Extraction chromatographic separation techniques based on U/TEVA and TEVA resins were utilized to separate uranium and thorium isotopes in complex matrices from environmental samples. This approach has the advantages of ease of quantitative analysis, small sample size, an absence of mixed waste solvents, complete separation of U/Th isotopes, acceptable chemical yields and good energy resolution in the alpha spectrum. The procedure for analyzing alpha-emitting isotopes of uranium and thorium in geothermal water from Peito, Taiwan, is illustrated in detail. It involves sample pre-concentration, filtration and separation by highly selective extraction chromatographic resins, followed by electroplating and alpha-spectroscopy. The analytical results show a chemical recovery exceeding 55% for U and 65% for Th, respectively, under optimized conditions. The efficient and cost-effective use of recyclable columns makes the analytical methods simple, accurate, rapid, reliable and robust.

  15. Determination of uranium and thorium contents inside different materials using track detectors and mean critical angles

    CERN Document Server

    Misdaq, M A; Ktata, A; Merzouki, A; Youbi, N

    1999-01-01

    The critical angles of the CR-39 (theta sub c) and LR-115 type II (theta sub c ') solid state nuclear track detectors (SSNTD) for detecting alpha-particles emitted by the uranium and thorium series have been evaluated by calculating the corresponding ranges of the emitted alpha-particles in different material samples and in the SSNTD studied. The influence of the emitted alpha-particles initial and residual energies on the critical angles of the SSNTD studied has been investigated. The uranium and thorium contents of different geological samples have been evaluated by exploiting data obtained for the critical angles of the CR-39 and LR-115 type II solid state nuclear track detectors and measuring the corresponding densities of tracks.

  16. Determination of Natural and Depleted Uranium in Urine at the ppt Level: An Interlaboratory Analytical Exercise

    Science.gov (United States)

    2002-10-01

    Q-MS) la spectrom6trie de masse A ionisation thermique (TIMS) et l’analyse par activation neutronique (NAA). Des rrsultats complets ont 6t6 obtenus de...laboratoire h6te. L’analyse par activation neutronique et TIMS enregistraient des concentrations d’uranium total qui diffrraient de celles du laboratoire...Q-MS) la spectromdtrie de masse h ionisation thermique (TIMS) et l’analyse par activation neutronique (NAA). RWsultats: Des ensembles de 12

  17. Determination of uranium and thorium in Egyptian monazite by gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, A.M. [Atomic Energy Authority, Cairo (Egypt). Dept. of Reactor and Neutron Physics; Abdel-Wahab, M.; Nada, A.; El-Dine, N.W. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Khazbak, A. [Nuclear Material Authority, Cairo (Egypt)

    1997-01-01

    A sample of pure monazite prepared from beach sands, from the Abu-Khashaba area near Rosetta, has been investigated by means of passive and active measurement techniques. The natural gamma-rays emitted from the sample under investigation as well as those emitted following neutron activation are measured. The sample and the standards used were prepared and simultaneously irradiated in a neutron flux of the order 10{sup 3} n cm{sup -2} s{sup -1} using the Egyptian Research Reactor-1 (ET-RR-1). The spectrometry facilities of the nuclear physics laboratories, specifically, the hyper-pure germanium detection systems and some special computer programs, were used for the measurements. The gamma-ray peaks at 270.2, 583.1, 911.2, 968.8 and 2204.2 keV for thorium and uranium daughters in passive measurements and the gamma-ray peaks at 311.8 and 277.6 keV for active measurements are used for estimation of thorium and uranium concentration values. The values obtained were between 46{+-}2 and 59{+-}3 ppm and 687{+-}34 and 729{+-}36 ppm for uranium and thorium, respectively. (Author).

  18. Determination of Nitric Acid in Aqueous Solution of Uranium and Plutonium Purification Cycle by Near Infrared Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    LI; Ding-ming; WANG; Lin; ZHANG; Li-hua; GONG; Yan-ping; MU; Ling; WU; Ji-zong

    2012-01-01

    <正>The concentration of nitric acid interfered with the distribution of uranium and plutonium in nuclear fuel reprocessing process. So, in the reprocessing process control analysis, the determination of the free acid plays an important role. Traditional laboratory analytical method of free acid needs large size sample and is time-consuming. Hence, development of fast analytical method for free acid has important significance for the reprocessing process control analysis. Near-infrared spectroscopy (NIRS) has been proved to be a powerful analytical tool and used in various fields, it’s seldom, however, used in spent

  19. Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan.

    Science.gov (United States)

    Abusini, M; Al-Ayasreh, K; Al-Jundi, J

    2008-01-01

    Soil samples were collected from six different locations in Araba valley, situated between Aqaba port and Dead sea. The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean activity concentration for (238)U, (232)Th and (40)K was found to be in the range 19 +/- 1.4 to 38.7 +/- 3, 14.3 +/- 0.8 to 35 +/- 3.2 and 94 +/- 18.9 to 762 +/- 47.4 Bq kg(-1), respectively. These results indicate that the mean concentrations of (238)U, (232)Th and (40)K in the populated Araba valley are lower than those in other populated areas. On the other hand, the concentrations of the major oxides (Al(2)O(3), SiO(2), K(2)O, CaO and Fe(2)O(3)) in the samples were determined using wavelength dispersive X-ray fluorescence. High potassium and iron content in some samples might be attributed to the active faults, which refer to the Dead sea transform fault.

  20. Determination of the elemental concentration of uranium and thorium in the products and by-products of amang tin tailings process

    Science.gov (United States)

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Elias, M. S.

    2017-01-01

    Amang or tin tailing is processed into concentrated ores and other economical valuable minerals such as monazite, zircon, xenotime, ilmenite etc. Besides that, the tailings from these ores may have a significant potential source of radiation exposure to amang plants' workers. This study was conducted to determine the elemental concentration of uranium and thorium in mineral samples collected from five amang tailing factories. The concentration of uranium and thorium was carried out by using instrumental neutron activation analysis (INAA) relative technique. The concentration of uranium and thorium in ppm obtained in this study are as follows: raw (189-1064) and (622-4965); monazite (1076-1988) and (3467-33578); xenotime 4053 and 5540; zircon (309-3090) and (387-6339); ilmenite (104-583) and (88-1205); rutile (212-889) and (44-1119); pyrite (7-43) and (9-132); and waste (5-338) and (9-1218) respectively. The analysis results shows that the monazite, xenotime and zircon have high content of uranium and thorium, whereas ilmenite, rutile, pyrite and waste have lower concentration compare with raw materials after tailing process. The highest values of uranium and thorium concentrations (4053 ± 428 ppm and 33578 ± 873 ppm, respectively) were observed in xenotime and monazite; whereas the lowest value was 5.48 ± 0.86 ppm of uranium recorded in waste (sand) and 9 ± 0.32 ppm of thorium for waste (sand) and pyrite.

  1. Flow injection online spectrophotometric determination of uranium after preconcentration on XAD-4 resin impregnated with nalidixic acid.

    Science.gov (United States)

    Shahida, Shabnam; Ali, Akbar; Khan, Muhammad Haleem; Saeed, Muhammad Mufazzal

    2013-02-01

    In this work, spectrophotometer was used as a detector for the determination of uranium from water, biological, and ore samples with a flow injection system coupled with solid phase extraction. In order to promote the online preconcentration of uranium, a minicolumn packed with XAD-4 resin impregnated with nalidixic acid was utilized. The system operation was based on U(VI) ion retention at pH 6 in the minicolumn at flow rate of 15.2 mL min(-1). The uranium complex was removed from the resin by 0.1 mol dm(-3) HCl at flow rate of 3.2 mL min(-1) and was mixed with arsenazo III solution (0.05 % solution in 0.1 mol dm(-3) HCl, 3.2 mL min(-1)) and driven to flow through cell of spectrophotometer where its absorbance was measured at 651 nm. The influence of chemical (pH and HCl (as eluent and reagent medium) concentration) and flow (sample and eluent flow rate and preconcentration time) parameters that could affect the performance of the system as well as the possible interferents was investigated. At the optimum conditions for 60 s preconcentration time (15.2 mL of sample volume), the method presented a detection limit of 1.1 μg L(-1), a relative standard deviation (RSD) of 0.8 % at 100 μg L(-1), enrichment factor of 30, and a sample throughput of 42 h(-1), whereas for 300 s of the preconcentration time (76 mL of sample volume), a detection limit of 0.22 μg L(-1), a RSD of 1.32 % at 10 μg L(-1), enrichment factor of 150, and a sampling frequency of 11 h(-1) were reported.

  2. Determination of uranium concentration and burn-up of irradiated reactor fuel in contaminated areas in Belarus using uranium isotopic ratios in soil samples

    Energy Technology Data Exchange (ETDEWEB)

    Mironov, V.P.; Matusevich, J.L.; Kudrjashov, V.P.; Ananich, P.I.; Zhuravkov, V.V. [Inst. of Radiobiology, Minsk Univ. (Belarus); Boulyga, S.F. [Inst. of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Becker, J.S. [Central Div. of Analytical Chemistry, Research Centre Juelich, Juelich (Germany)

    2005-07-01

    An analytical method is described for the estimation of uranium concentrations, of {sup 235}U/{sup 238}U and {sup 236}U/{sup 238}U isotope ratios and burn-up of irradiated reactor uranium in contaminated soil samples by inductively coupled plasma mass spectrometry. Experimental results obtained at 12 sampling sites situated on northern and western radioactive fallout tails 4 to 53 km distant from Chernobyl nuclear power plant (NPP) are presented. Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 2.1 x 10{sup -9}g/g to 2.0 x 10{sup -6}g/g depending mainly on the distance from Chernobyl NPP. A slight variation of the degree of burn-up of spent reactor uranium was revealed by analyzing {sup 235}U/{sup 238}U and {sup 236}U/{sup 238}U isotope ratios and the average value amounted to 9.4{+-}0.3 MWd/(kg U). (orig.)

  3. Bioassays with caged hyalella azteca to determine in situ toxicity downstream of two Saskatchewan, Canada, uranium operations.

    Science.gov (United States)

    Robertson, Erin L; Liber, Karsten

    2007-11-01

    The main objectives of this in situ study were to evaluate the usefulness of an in situ bioassay to determine if downstream water bodies at the Key Lake and Rabbit Lake uranium operations (Saskatchewan, Canada) were toxic to Hyalella azteca and, if toxicity was observed, to differentiate between the contribution of surface water and sediment contamination to in situ toxicity. These objectives were achieved by performing 4-d in situ bioassays with laboratory-reared H. azteca confined in specially designed, paired, surface water and sediment exposure chambers. Results from the in situ bioassays revealed significant mortality, relative to the respective reference site, at the exposure sites at both Key Lake (p azteca at both operations, although this relationship was stronger at Key Lake. At Key Lake, the primary cause of aquatic toxicity to H. azteca did not appear to be correlated with the variables measured in this study, but most likely with a pulse of organic mill-process chemicals released during the time of the in situ study-a transient event that was caused by a problem with the mill's solvent extraction process. The suspected cause of in situ toxicity to H. azteca at Rabbit Lake was high levels of uranium in surface water, sediment, and pore water.

  4. [A fluorescence quenching method for the determination of trace chlorite in water with rhodamine B].

    Science.gov (United States)

    Kang, Cai-yan; Jiang, Zhi-liang; Xi, Dan-li

    2007-02-01

    In acidic sodium acetate-HCl buffer solution containing KI, Rhodamine B (RhB) has a fluorescence peak at 580 nm. When ClO2(-) exists fluorescence quenching occur. The fluorescence quenching intensity is linear with the concentration of ClO2(-) in the range of 0.0218-0.51 microg x mL(-1). Based on this, a new, simple, sentisive fluorescence method has been proposed for the determination of ClO2(-) in water, with satisfactory results.

  5. Determination of uranium traces in fuel cans of nuclear reactors; Determinacion de trazas de uranio en vainas de combustible de reactores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, C.E.; Benavides M, A.M.; Sanchez P, L.A.; Nava S, G.F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The objective of this work is to quantify the uranium content that as impurity can be found in zircon and zircaloy alloys which are used in the construction of fuel cans. The determination of this serves as a quality control measure due to that the increment of uranium content in alloy, diminishing the corrosion resistance. The fluorimetric method was used to do this determination. It is a very sensitive, reliable, rapid method also high reproducibility and repeatability as well as low detection limits (0.25 mg/kg). (Author)

  6. Response of Substituted Indoleacetic Acids in the Indolo-alpha-pyrone Fluorescence Determination

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Böttger, M.; Kaiser, P.

    1978-01-01

    .-pyrones. Other halogenated indoleacetic acids show between zero and 60% of the fluorescence of IAA. Apparently the concentration of IAA cannot be determined in crude extracts in the presence of 4-chloro- or 5-hydroxy-indoleacetic acid, because separate determinations of each of these compounds are not possible......The method of indolo-.alpha.-pyrone fluorescence-determination of IAA was investigated to study possible interference from 4-chloro-indoleacetic acid and 5-hydroxyindoleacetic acid, which occur naturally. Both compounds show about 40% of the fluorescence of IAA after conversion into their .alpha...

  7. Fmoc-Cl fluorescent determination for amino groups of nanomaterial science.

    Science.gov (United States)

    Zhang, Y; Chen, Y

    2012-06-01

    With the wide application of nanomaterials, the quantification of functional groups on nanomaterial surface becomes more and more necessary. A heterogeneous 9-fluorenylmethoxy carbonyl chloride (Fmoc-Cl) fluorescent method using an aqueous solution was established to determinate amino groups on nanomaterial surface. The effect factors of determination were investigated and the assay was optimised. The Fmoc fluorescent method is 200-fold more sensitive than the current UV assay using an organic solvent, and compared with chemical ninhydrin method and physical elemental analysis. Heterogeneous Fmoc-Cl fluorescent method can be used to determine amino groups on nanomaterials with big size, which is difficult to undergo a direct detection.

  8. Determination of biological activity from fluorescence-lifetime measurements in Saccharomyces cerevisiae

    Science.gov (United States)

    Rudek, F.; Baselt, T.; Lempe, B.; Taudt, C.; Hartmann, P.

    2015-03-01

    The importance of fluorescence lifetime measurement as an optical analysis tool is growing. Many applications already exist in order to determine the fluorescence lifetime, but the majority of these require the addition of fluorescence-active substances to enable measurements. Every usage of such foreign materials has an associated risk. This paper investigates the use of auto-fluorescing substances in Saccharomyces cerevisiae (Baker's yeast) as a risk free alternative to fluorescence-active substance enabled measurements. The experimental setup uses a nitrogen laser with a pulse length of 350 ps and a wavelength of 337 nm. The excited sample emits light due to fluorescence of NADH/NADPH and collagen. A fast photodiode collects the light at the output of an appropriate high-pass edge-filter at 400 nm. Fluorescence lifetimes can be determined from the decay of the measurement signals, which in turn characterizes the individual materials and their surrounding environment. Information about the quantity of the fluorescence active substances can also be measured based on the received signal intensity. The correlation between the fluorescence lifetime and the metabolic state of Saccharomyces cerevisiae was investigated and is presented here.

  9. A Fluorescence-Based Determination of Quantum Efficiency

    Science.gov (United States)

    2013-12-01

    Vis)-near infrared (NIR) spectrophotometer • 1% ceramic Nd-doped Nd:YAG sample provided by Dr. Larry Merkle • 10% crystal Yb-doped Yb:YAG sample...fluorescence. These data were initially inconclusive since a calibration of the sphere and the sensitivity of the InGaAs detector had not been performed...set could then be divided by this calibration curve to scale the data relative to the system’s highest sensitivity at roughly 1330 nm. Applying

  10. Carbon dots based fluorescent sensor for sensitive determination of hydroquinone.

    Science.gov (United States)

    Ni, Pengjuan; Dai, Haichao; Li, Zhen; Sun, Yujing; Hu, Jingting; Jiang, Shu; Wang, Yilin; Li, Zhuang

    2015-11-01

    In this paper, a novel biosensor based on Carbon dots (C-dots) for sensitive detection of hydroquinone (H2Q) is reported. It is interesting to find that the fluorescence of the C-dots could be quenched by H2Q directly. The possible quenching mechanism is proposed, which shows that the quenching effect may be caused by the electron transfer from C-dots to oxidized H2Q-quinone. Based on the above principle, a novel C-dots based fluorescent probe has been successfully applied to detect H2Q. Under the optimal condition, detection limit down to 0.1 μM is obtained, which is far below U.S. Environmental Protection Agency estimated wastewater discharge limit of 0.5 mg/L. Moreover, the proposed method shows high selectivity for H2Q over a number of potential interfering species. Finally, several water samples spiked with H2Q are analyzed utilizing the sensing method with satisfactory recovery. The proposed method is simple with high sensitivity and excellent selectivity, which provides a new approach for the detection of various analytes that can be transformed into quinone.

  11. Increasing precision of lifetime determination in fluorescence lifetime imaging

    Science.gov (United States)

    Chang, Ching-Wei; Mycek, Mary-Ann

    2010-02-01

    The interest in fluorescence lifetime imaging microscopy (FLIM) is increasing, as commercial FLIM modules become available for confocal and multi-photon microscopy. In biological FLIM applications, low fluorescence signals from samples can be a challenge, and this causes poor precision in lifetime. In this study, for the first time, we applied wavelet-based denoising methods in time-domain FLIM, and compared them with our previously developed total variation (TV) denoising methods. They were first tested using artificial FLIM images. We then applied them to lowlight live-cell images. The results demonstrated that our TV methods could improve lifetime precision multi-fold in FLIM images and preserve the overall lifetime and pre-exponential term values when improving local lifetime fitting, while wavelet-based methods were faster. The results here can enhance the precision of FLIM, especially for low-light and / or fast video-rate imaging, to improve current and rapidly emerging new applications of FLIM such as live-cell, in vivo whole-animal, or endoscopic imaging.

  12. A study of uranium uptake in plants

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, A.; Singh, Surinder; Virk, H.S. (Guru Nanak Dev Univ., Amritsar (India). Dept. of Physics)

    1988-01-01

    A fission track technique has been used to study the uptake of uranium in Tomato Plant. Lexan plastic has been employed as the external detector for recording induced fission tracks due to uranium. The uranium uptake rate is found to increase as the growth proceeds. The uranium concentration is also determined in Phlox, Calendula and Dog Flower, grown under normal conditions. The uranium content is found to vary in different parts of the plants. (author).

  13. Characterization of the uranium (VI) complexes formed by the cells of three A. ferrooxidans eco-types using time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    Energy Technology Data Exchange (ETDEWEB)

    Merroun, M.; Geipel, G.; Selenska-Pobell, S.

    2002-05-01

    TRLFS was used to study the properties of the uranium complexes formed by the cells of the three recently described eco-types of A. ferrooxidans /1/. The results demonstrate that the lifetimes of the complexes are type-specific and are increasing in the same order as the capability of the bacterial strains to accumulate uranium. (orig.)

  14. Determination of boron in uranium aluminum silicon alloy by spectrophotometry and estimation of expanded uncertainty in measurement

    Science.gov (United States)

    Ramanjaneyulu, P. S.; Sayi, Y. S.; Ramakumar, K. L.

    2008-08-01

    Quantification of boron in diverse materials of relevance in nuclear technology is essential in view of its high thermal neutron absorption cross section. A simple and sensitive method has been developed for the determination of boron in uranium-aluminum-silicon alloy, based on leaching of boron with 6 M HCl and H 2O 2, its selective separation by solvent extraction with 2-ethyl hexane 1,3-diol and quantification by spectrophotometry using curcumin. The method has been evaluated by standard addition method and validated by inductively coupled plasma-atomic emission spectroscopy. Relative standard deviation and absolute detection limit of the method are 3.0% (at 1 σ level) and 12 ng, respectively. All possible sources of uncertainties in the methodology have been individually assessed, following the International Organization for Standardization guidelines. The combined uncertainty is calculated employing uncertainty propagation formulae. The expanded uncertainty in the measurement at 95% confidence level (coverage factor 2) is 8.840%.

  15. Analytical strategies for uranium determination in natural water and industrial effluents samples; Estrategias analiticas para determinacao de uranio em amostras de aguas e efluentes industriais

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Juracir Silva

    2011-07-01

    The work was developed under the project 993/2007 - 'Development of analytical strategies for uranium determination in environmental and industrial samples - Environmental monitoring in the Caetite city, Bahia, Brazil' and made possible through a partnership established between Universidade Federal da Bahia and the Comissao Nacional de Energia Nuclear. Strategies were developed to uranium determination in natural water and effluents of uranium mine. The first one was a critical evaluation of the determination of uranium by inductively coupled plasma optical emission spectrometry (ICP OES) performed using factorial and Doehlert designs involving the factors: acid concentration, radio frequency power and nebuliser gas flow rate. Five emission lines were simultaneously studied (namely: 367.007, 385.464, 385.957, 386.592 and 409.013 nm), in the presence of HN0{sub 3}, H{sub 3}C{sub 2}00H or HCI. The determinations in HN0{sub 3} medium were the most sensitive. Among the factors studied, the gas flow rate was the most significant for the five emission lines. Calcium caused interference in the emission intensity for some lines and iron did not interfere (at least up to 10 mg L{sup -1}) in the five lines studied. The presence of 13 other elements did not affect the emission intensity of uranium for the lines chosen. The optimized method, using the line at 385.957 nm, allows the determination of uranium with limit of quantification of 30 {mu}g L{sup -1} and precision expressed as RSD lower than 2.2% for uranium concentrations of either 500 and 1000 {mu}g L{sup -1}. In second one, a highly sensitive flow-based procedure for uranium determination in natural waters is described. A 100-cm optical path flow cell based on a liquid-core waveguide (LCW) was exploited to increase sensitivity of the arsenazo 111 method, aiming to achieve the limits established by environmental regulations. The flow system was designed with solenoid micro-pumps in order to improve mixing and

  16. Determination of ranitidine, nizatidine, and cimetidine by a sensitive fluorescent probe.

    Science.gov (United States)

    Chang, Yin-Xia; Qiu, Yue-Qin; Du, Li-Ming; Li, Chang-Feng; Guo, Min

    2011-10-21

    A validated, simple, and sensitive fluorescence quenching method for the determination of ranitidine, nizatidine, and cimetidine in tablets and biological fluids is presented. This is the first single fluorescence method reported for the analysis of all three H(2) antagonists. The competitive reaction between the investigated drug and the palmatine probe for the occupancy of the cucurbit[7]uril (CB[7]) cavity was studied using spectrofluorometry. CB[7] was found to react with the probe to form a stable complex. The fluorescence intensity of the complex was also enhanced greatly. However, the addition of the drug dramatically quenched the fluorescence intensity of the complex. Accordingly, a new fluorescence quenching method for the determination of the studied drugs was established. The different experimental parameters affecting the fluorescence quenching intensity were studied carefully. At optimum reaction conditions, the rectilinear calibration graphs between the fluorescence quenching values (ΔF) and the medicament concentration were obtained in the concentration range of 0.04-1.9 μg mL(-1) for the investigated drugs. The limits of detection ranged from 0.013 to 0.030 μg mL(-1) at 495 nm using an excitation wavelength of 343 nm. The proposed method can be used for the determination of the three H(2) antagonists in raw materials, dosage forms and biological fluids.

  17. Determination of metal ions by fluorescence anisotropy exhibits a broad dynamic range

    Science.gov (United States)

    Thompson, Richard B.; Maliwal, Badri P.; Fierke, Carol A.

    1998-05-01

    Recently, we have shown that metal ions free in solution may be determined at low levels by fluorescence anisotropy (polarization) measurements. Anisotropy measurements enjoy the advantages of wavelength ratiometric techniques for determining metal ions such as calcium, because anisotropy measurements are ratiometric as well. Furthermore, fluorescence anisotropy may be imaged in the microscope. An advantage of anisotropy not demonstrated for wavelength ratiometric approaches using indicators such as Fura-2 and Indo-1 is that under favorable circumstances anisotropy-based determinations exhibit a much broader dynamic range in metal ion concentration. Determinations of free Zn(II) in the picomolar range are demonstrated.

  18. Direct Separation of Molybdenum from Solid Uranium Matrices Employing Pyrohydrolysis, a Green Separation Method, and Its Determination by Ion Chromatography.

    Science.gov (United States)

    Mishra, Vivekchandra G; Thakur, Uday K; Shah, Dipti J; Gupta, Neeraj K; Jeyakumar, Subbiah; Tomar, Bhupendra S; Ramakumar, Karanam L

    2015-11-01

    Pyrohydrolysis is a well-established separation method, and it is being used as a sample preparation method for several materials for further determination of non-metals such as halogens, boron, and sulfur. Analytes are retained in a diluted solution that is suitable for carrying out analysis by several determination techniques and minimizing the use of concentrated reagents. Pyrohydrolysis separation of metals has not been reported yet. The present study demonstrates the pyrohydrolysis separation of Mo as MoO4(2-) from uranium materials and its subsequent determination using ion chromatography coupled with suppressed conductivity detector. With use of TGA and XRD the volatilization behavior of Mo was studied. Important parameters for the pyrohydrolysis method required for the quantitative separation of Mo were evaluated. The precision of the method was better than 5% at 25 ppm of Mo. The accuracy was evaluated by analysis of a CRM (U3O8-ILCE-IV). The method was applied to determine Mo in ammonium diuranate samples, where the conventional methods suffer from the loss of Mo.

  19. UO(2) 2+ speciation determines uranium toxicity and bioaccumulation in an environmental Pseudomonas sp. isolate.

    Science.gov (United States)

    Vanengelen, Michael R; Field, Erin K; Gerlach, Robin; Lee, Brady D; Apel, William A; Peyton, Brent M

    2010-04-01

    In the present study, experiments were performed to investigate how representative cellulosic breakdown products, when serving as growth substrates under aerobic conditions, affect hexavalent uranyl cation (UO(2) (2+)) toxicity and bioaccumulation within a Pseudomonas sp. isolate (designated isolate A). Isolate A taken from the Cold Test Pit South (CTPS) region of the Idaho National Laboratory (INL), Idaho Falls, ID, USA. The INL houses low-level uranium-contaminated cellulosic material and understanding how this material, and specifically its breakdown products, affect U-bacterial interactions is important for understanding UO(2) (2+) fate and mobility. Toxicity was modeled using a generalized Monod expression. Butyrate, dextrose, ethanol, and lactate served as growth substrates. The potential contribution of bicarbonate species present in high concentrations was also investigated and compared with toxicity and bioaccumulation patterns seen in low-bicarbonate conditions. Isolate A was significantly more sensitive to UO(2) (2+) and accumulated significantly more UO(2) (2+) in low-bicarbonate concentrations. In addition, UO(2) (2+) growth inhibition and bioaccumulation varied depending on the growth substrate. In the presence of high bicarbonate concentrations, sensitivity to UO(2) (2+) inhibition was greatly mitigated, and did not vary between the four substrates tested. The extent of UO(2) (2+) accumulation was also diminished. The observed patterns were related to UO(2) (2+) aqueous complexation, as predicted by MINTEQ (ver. 2.52) (Easton, PA, USA). In the low- bicarbonate medium, the presence of positively charged and unstable UO(2) (2+)-hydroxide complexes explained both the greater sensitivity of isolate A to UO(2) (2+), and the ability of isolate A to accumulate significant amounts of UO(2) (2+). The exclusive presence of negatively charged and stable UO(2) (2+)-carbonate complexes in the high bi-carbonate medium explained the diminished sensitivity of

  20. pFe(3+) determination of multidentate ligands by a fluorescence assay.

    Science.gov (United States)

    Ma, Yongmin; Zhou, Tao; Hider, Robert C

    2015-05-21

    The fluorescence intensity of the iron-CP691 complex in the presence of a competing multidentate ligand is associated with pFe(3+) of the competing ligand and the relative fluorescence has a linear correlation with the pFe(3+) values. A correlation was also found to exist between the relative fluorescence and the ratio of a competing ligand to the probe CP691. Based on this assay, the pFe(3+) value of a range of hexadentate ligands, dendrimers and polymers can be determined when they fall in the range 24.5-30.5. Only small quantities of chelators are required for this assay.

  1. Determination of epristeride by its quenching effect on the fluorescence of L-tryptophan

    Institute of Scientific and Technical Information of China (English)

    Ai-Qin Gong; Xia-Shi Zhu

    2013-01-01

    A rapid, novel spectrofluorimetric method to determine epristeride (EP) in biological fluids and a pharmaceutical formulation was developed, based on the fact that fluorescence intensity of L-tryptophan could be quenched by EP in the medium of pH ¼ 9.0. The various factors influencing fluorescence quenching were discussed. The quenching mechanism was investigated with the quenching type, synchronous fluorescence spectra and quantum efficiency. Under the optimized conditions, fluorescence quenching value (ΔF ¼ FL-tryptophan-FEP-L-tryptophan) showed a good linear relationship with the EP concentration ranging from 0.4 to 12.0μg/mL. The linearity, recovery and limit of detection demonstrated that the proposed method was suitable for EP determination in biological fluids and EP tablets. The method was successfully applied to the analysis of EP in real samples and the obtained results were in good agreement with the results of the official method.

  2. Standard test method for determination of bromine and chlorine in UF6 and uranyl nitrate by X-Ray fluorescence (XRF) spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This method covers the determination of bromine (Br) and chlorine (Cl) in uranium hexafluoride (UF6) and uranyl nitrate solution. The method as written covers the determination of bromine in UF6 over the concentration range of 0.2 to 8 μg/g, uranium basis. The chlorine in UF6 can be determined over the range of 4 to 160 μg/g, uranium basis. Higher concentrations may be covered by appropriate dilutions. The detection limit for Br is 0.2 μg/g uranium basis and for Cl is 4 μg/g uranium basis. 1.2 This standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  3. Uranium(Ⅵ) Complex Based on a Fluoroquinolone Ligand with Green Fluorescent Emission%具有绿色荧光发射效应的氟喹诺酮-铀(Ⅵ)配合物

    Institute of Scientific and Technical Information of China (English)

    瞿志荣

    2008-01-01

    A uranium(Ⅵ) complex [UO2(1-ethyl-6,8-difluoro-7-(3-methyl-piperazinium-1-yl)-4-oxo-1,4-dihydro-quinwater at 80 ℃ in Pyrex tube. The crystal belongs to monoclinic system, space group P21/c, with a=1.430(3) nm, b=1.032 1(18) nm, c=1.729(3) nm,β=106.67(3)° V=2.458(6) nm3, Z=4. This complex is a good green fluorescent material in solid state at room temperature. CCDC: 660959.

  4. A novel aeration-assisted homogenous liquid-liquid microextration for determination of thorium and uranium in water and hair samples by inductively coupled plasma-mass spectroscopy.

    Science.gov (United States)

    Veyseh, Somayeh; Niazi, Ali

    2016-01-15

    A novel method based on aeration-assisted homogeneous liquid-liquid microextraction using high density solvent is presented, which is combined with inductively coupled plasma-mass spectroscopy in which simultaneous preconcentration and determination of thorium and uranium with arsenazo III as the chelating reagent is carried out. To achieve optimum conditions, several parameters such as pH, concentration of arsenazo III, extraction and homogenous solvent types and their volumes, salt concentration and extraction time were investigated. Under which, the calibration graphs were linear in the range of 0.5-600.0ng L(-1) for thorium and 0.3-550.0ng L(-1) for uranium. Good linearities were obtained for both analytes with R(2) values larger than 0.9990. The limits of detection (LOD, 3Sb/m, n=5) of this method were 0.12 and 0.09ng L(-1), and the enrichment factors were estimated to be 370 and 410 for thorium and uranium, respectively. The proposed method was applied to determine the thorium and uranium in human hair and different environmental water samples. Acceptable recoveries ranged from 99.4% to 100.7% with standard deviation of 0.05 to 0.17.

  5. 2-Hydroxy-1-naphthaldehyde-P-hydroxybenzoichydrazone: A New Chromogenic Reagent for the Determination of Thorium(IV and Uranium(VI

    Directory of Open Access Journals (Sweden)

    V. S. Anasuya Devi

    2013-01-01

    Full Text Available Simple, sensitive, selective, direct, derivative, and simultaneous spectrophotometric methods are developed for the determination of uranium and thorium individually and simultaneously. The methods are based on the reaction of 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH with thorium(IV and uranium(VI. HNAHBH reacts with thorium and uranium at pH 6.0 forming stable yellow and reddish brown coloured complexes, respectively. [Th(IV-HNAHBH] complex shows maximum absorbance at 415 nm. Beer’s law is obeyed over the concentration range 0.464–6.961 μg mL−1 with a detection limit of 0.01 μg mL−1 and molar absorptivity, ε, 3.5 × 104 L mol−1 cm−1. Maximum absorbance shown by [U(VI-HNAHBH] complex is at 410 nm with Beer’s law range 0.476–7.140 μg mL−1, detection limit 0.139 μg mL−1 and molar absorptivity, ε, 1.78 × 104 L mol−1 cm−1. Highly sensitive and selective second-order derivative methods are reported for the direct and simultaneous determination of Th(IV and U(VI using HNAHBH. The applicability of the developed methods is tested by analyzing water, ore, fertilizer, and gas mantle samples for thorium and uranium content.

  6. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  7. Developing a new micro cloud point extraction method for simultaneous preconcentration and spectrophotometric determination of uranium and vanadium in brine.

    Science.gov (United States)

    Ghasemi, Elham; Kaykhaii, Massoud

    2015-01-01

    A fast, simple, and economical method was developed for simultaneous spectrophotometric determination of uranium(VI) and vanadium(V) in water samples based on micro cloud point extraction (MCPE) at room temperature. This is the first report on the simultaneous extraction and determination of U(VI) and V(V). In this method, Triton X114 was employed as a non-ionic surfactant for the cloud point procedure and 4-(2-pyridylazo) resorcinol (PAR) was used as the chelating agent for both analytes. To reach the cloud point at room temperature, the MCPE procedure was carried out in brine. The factors influencing the extraction efficiency were investigated and optimized. Under the optimized condition, the linear calibration curve was found to be in the concentration range between 100 - 750 and 50 - 600 μg L(-1) for U(VI) and V(V), respectively, with a limit of detection of 17.03 μg L(-1) (U) and 5.51 μg L(-1) (V). Total analysis time including microextraction was less than 5 min.

  8. Determination of torasemide by fluorescence quenching method with some dihalogenated fluorescein dyes as probes

    Science.gov (United States)

    Cui, Zhiping; Liu, Shaopu; Liu, Zhongfang; Li, Yuanfang; Hu, Xiaoli; Tian, Jing

    2013-10-01

    A novel fluorescence quenching method for the determination of torasemide (TOR) with some dihalogenated fluorescein dyes as fluorescence probes was developed. In acidulous medium, TOR could interact with some dihalogenated fluorescein dyes such as dichlorofluorescein (DCF), dibromofluorescein (DBF) and diiodofluorescein (DIF) to form binary complexes, which could lead to fluorescence quenching of above dihalogenated fluorescein dyes. The maximum fluorescence emission wavelengths were located at 532 nm (TOR-DCF), 535 nm (TOR-DBF) and 554 nm (TOR-DIF). The relative fluorescence intensities (ΔF = F0 - F) were proportional to the concentration of TOR in certain ranges. The detection limits were 4.8 ng mL-1 for TOR-DCF system, 9.8 ng mL-1 for TOR-DBF system and 35.1 ng mL-1 for TOR-DIF system. The optimum reaction conditions, influencing factors were studied; and the effect of coexisting substances was investigated owing to the highest sensitivity of TOR-DCF system. In addition, the reaction mechanism, composition and structure of the complex were discussed by quantum chemical calculation and Job's method. The fluorescence quenching of dihalogenated fluorescein dyes by TOR was a static quenching process judging from the effect of temperature and the Stern-Volmer plots. The method was satisfactorily applied to the determination of TOR in tablets and human urine samples.

  9. Determination of sunset yellow in soft drinks based on fluorescence quenching of carbon dots

    Science.gov (United States)

    Yuan, Yusheng; Zhao, Xin; Qiao, Man; Zhu, Jinghui; Liu, Shaopu; Yang, Jidong; Hu, Xiaoli

    2016-10-01

    Fluorescent carbon dots was prepared by heating N-(2-hydroxyethyl)ethylene diaminetriacetic acid in air. The carbon dots were not only highly soluble in water but also uniform in size, and possessed strong blue fluorescence and excitation wavelength-dependent emission properties with the maximum excitation and emission wavelength at 366 nm and 423 nm, respectively. Food colorant sunset yellow whose excitation and emission wavelength at 303 nm and 430 nm could selectively quench the fluorescence of carbon dots, efficient fluorescent resonance energy transfer between the carbon dots and sunset yellow is achieved. This was exploited to design a method for the determination of sunset yellow in the concentration range from 0.3 to 8.0 μmol L- 1, with a limit of detection (3 σ/k) of 79.6 nmol L- 1. Furthermore the fluorimetric detection method was established and validated for sunset yellow in soft drinks samples with satisfactory results.

  10. Determination for levels of uranium and thorium in water along Oum Er-Rabia river using alpha track detectors

    Directory of Open Access Journals (Sweden)

    M. Amrane

    2017-07-01

    Full Text Available Different river water samples have been collected and analyzed from different locations along Oum Er-Rbia River in Morocco. The uranium and thorium concentrations were investigated in the studied river and dam water samples. Mean activity concentrations of uranium and thorium in water were found to be between 12 and 37 Bq.m−3 and 2–10 Bq.m−3, respectively. The pH measured at all river water simples was slightly alkaline and ranged from 7.5 to 8.75. The electrical conductivity ranged from 2790 to 794 μS cm−1. It was found that uranium and thorium concentrations were correlated with some chemical parameters in Oum Er-Rabia River water. Uranium and thorium measurements in this river are important for monitoring environmental radioactivity and to know the geochemical behaviour of these radionuclides in the surficial water bearing environments.

  11. EPA Method EMSL-33: Isotopic Determination of Plutonium, Uranium, and Thorium in Water, Soil, Air, and Biological Tissue

    Science.gov (United States)

    SAM lists this method to provide for the analysis of isotopic plutonium, uranium and thorium, together or individually, in drinking water, aqueous/liquid, soil/sediment, surface wipe and/or air filter samples by alpha spectrometry.

  12. Uranium uptake by hydroponically cultivated crop plants

    Energy Technology Data Exchange (ETDEWEB)

    Soudek, Petr; Petrova, Sarka [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Benesova, Dagmar [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Faculty of Environment Technology, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6 (Czech Republic); Dvorakova, Marcela [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Vanek, Tomas, E-mail: vanek@ueb.cas.cz [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic)

    2011-06-15

    Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC{sub 50} value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC{sub 50} = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation. - Highlights: > The uranium accumulation in twenty different plant species varied from 0.160 to 0.011 mg/g DW. > Uranium is mainly localized in the root system. > Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba. > The phosphates deficiency increase the uranium uptake.

  13. Flow-injection technique for determination of uranium and thorium isotopes in urine by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Benkhedda, Karima; Epov, Vladimir N; Evans, R Douglas

    2005-04-01

    A sensitive and efficient flow-injection (FI) preconcentration and matrix-separation technique coupled to sector field ICP-mass spectrometry (SF-ICP-MS) has been developed and validated for simultaneous determination of ultra-low levels of uranium (U) and thorium (Th) in human urine. The method is based on selective retention of U and Th from a urine matrix, after microwave digestion, on an extraction chromatographic TRU resin, as an alternative to U/TEVA resin, and their subsequent elution with ammonium oxalate. Using a 10 mL sample, the limits of detection achieved for 238U and 232Th were 0.02 and 0.03 ng L(-1), respectively. The accuracy of the method was checked by spike-recovery measurements. Levels of U and Th in human urine were found to be in the ranges 1.86-5.50 and 0.176-2.35 ng L(-1), respectively, well in agreement with levels considered normal for non-occupationally exposed persons. The precision obtained for five replicate measurements of a urine sample was 2 and 3% for U and Th, respectively. The method also enables on-line measurements of the 235U/238U isotope ratios in urine. Precision of 0.82-1.04% (RSD) was obtained for 235U/238U at low ng L(-1) levels, using the FI transient signal approach.

  14. Determination of the coefficient of uranium and thorium distribution in phosphogypsum for their use in sanitary landfills

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, Marcos Vinicius A.; Hama, Naruhiko; Jacomino, Vanusa M. F.; Ladeira, Ana Claudia Q.; Cota, Stela D. S., E-mail: mvmarchesi@hotmail.com, E-mail: sdsc@cdtn.br, E-mail: vmfj@cdtn.br, E-mail: ana.ladeira@cdtn.br, E-mail: naruhikohama@hotmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nascimento, Marcos Roberto Lopes do; Taddei, Maria Helena, E-mail: pmarcos@cnen.gov.br, E-mail: mhtaddei@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas

    2013-07-01

    Phosphogypsum is a byproduct from the production of phosphoric acid, and contain radionuclides, heavy metals and metalloids from phosphate rock. It represents a risk to the environment if improperly stored. Because it is composed mainly of dihydrated calcium sulphate, phosphogypsum can be used in anaerobic environments such as those found in landfills to accelerate microbial processes of decomposition of municipal solid waste and thus increase the life of these facilities. One of the options of your application being studied is the use of phosphogypsum replacing the covers of soil/clay in landfills. Besides reducing the demand for soil and clay, this application would be an alternative to disposal of the waste, since the alternatives are not sufficient for more than five million tons produced per year in Brazil. To ensure the safety of this application, the potential environmental impact of contaminants in phosphogypsum should be evaluated. The rate of leaching of contaminants are being studied by determining the coefficient of distribution of the contaminants in the phosphogypsum. Batch tests were performed by mixing different proportions of slurry and phosphogypsum. This work presents the results for the chain of uranium and natural thorium.

  15. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates.

    Science.gov (United States)

    Mas, J L; Villa, M; Hurtado, S; García-Tenorio, R

    2012-02-29

    This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and 206Pb/207Pb/208Pb, 238U/234U and 232Th/230Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA® extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Effect of Reaction Pathway on the Extent and Mechanism of Uranium(VI) Immobilization with Calcium and Phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Vrajesh S.; Maillot, Fabien; Wang, Zheming; Catalano, Jeffrey G.; Giammar, Daniel E.

    2016-03-15

    Phosphate addition to subsurface environments contaminated with uranium can be used as an in situ remediation approach. Batch experiments were conducted to evaluate the dependence of the extent and mechanism of uranium uptake on the pathway for reaction with calcium phosphates. At pH 4.0 and 6.0 uranium uptake occurred via autunite (Ca(UO2)(PO4)3) precipitation irrespective of the starting forms of calcium and phosphate. At pH 7.5, the uptake mechanism depended on the nature of the calcium and phosphate. When dissolved uranium, calcium, and phosphate were added simultaneously, uranium was structurally incorporated into a newly formed amorphous calcium phosphate solid. Adsorption was the dominant removal mechanism for uranium contacted with pre-formed amorphous calcium phosphate solids,. When U(VI) was added to a suspension containing amorphous calcium phosphate solids as well as dissolved calcium and phosphate, then removal occurred through precipitation (57±4 %) of autunite and adsorption (43±4 %) onto calcium phosphate. The solid phase speciation of the uranium was determined using X-ray absorption spectroscopy and laser induced fluorescence spectroscopy. Dissolved uranium, calcium, and phosphate concentrations with saturation index calculations helped identify removal mechanisms and determine thermodynamically favorable solid phases.

  17. Quantum dots (QDs) based fluorescence probe for the sensitive determination of kaempferol

    Science.gov (United States)

    Tan, Xuanping; Liu, Shaopu; Shen, Yizhong; He, Youqiu; Yang, Jidong

    2014-12-01

    In this work, using the quenching of fluorescence of thioglycollic acid (TGA)-capped CdTe quantum dots (QDs), a novel method for the determination of kaempferol (KAE) has been developed. Under optimum conditions, a linear calibration plot of the quenched fluorescence intensity at 552 nm against the concentration of KAE was observed in the range of 4-44 μg mL-1 with a detection limit (3σ/K) of 0.79 μg mL-1. In addition, the detailed reaction mechanism has also been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption and fluorescence (FL) spectroscopy. The method has been applied for the determination of KAE in pharmaceutical preparations with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation.

  18. Methyl-β-Cyclodextrin /Cetyltrimethyl Ammonium Bromide Synergistic Sensitized Fluorescence Method for the Determination of Levofloxacin.

    Science.gov (United States)

    Ren, Qiuyi; Zhu, Xiashi

    2016-03-01

    A novel method of methyl-β-cyclodextrin (methyl-β-CD) and cetyltrimethyl ammonium bromide (CTAB) synergistic sensitized fluorescence analysis to determine levofloxacin (LVFX) was developed. The results were shown that the fluorescence intensity of LVFX was increased a lot in the system of methyl-β-cyclodextrin-CTAB medium. Under the conditions of λ(ex/em )= 330/507 nm and pH 4.5, the linear range and the detection limit for LVFX were found to be 0.040 ~ 4.0 μg/mL and 0.3 ng/mL, respectively. The mechanism of sensitized fluorescence method was discussed by the solubilization capacity and the microenvironment of medium. The proposed method has been applied for the determination of LVFX in eye drops real samples and human serum with satisfactory recovery.

  19. Determination of uranium and thorium by neutron activation analysis applied to fossil samples dating

    Energy Technology Data Exchange (ETDEWEB)

    Ticianelli, Regina B.; Figueiredo, Ana Maria Graciano; Zahn, Guilherme S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Kinoshita, Angela; Baffa, Oswaldo [Universidade de Sao Paulo (FFCRLP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto. Dept. de Fisica

    2011-07-01

    Electron Spin Resonance (ESR) dating is based on the fact that ionizing radiation can create stable free radicals in insulating materials, like tooth enamel and bones. The concentration of these radicals - determined by ESR - is a function of the dose deposed in the sample along the years. The accumulated dose of radiation, called Archaeological Dose, is produced by the exposition to environmental radiation provided by U, Th, K and cosmic rays. If the environmental dose rate in the site where the fossil sample is found is known, it is possible to convert this dose into the age of the sample. The annual dose rate coming from the radioactive elements present in the soil and in the sample itself can be calculated by determining the U, Th and K concentration. Therefore, the determination of the dose rate depends on the concentration of these main radioactive elements. Neutron Activation Analysis has the sensitivity and the accuracy necessary to determine U, Th and K with this objective. Depending on the composition of the sample, the determination of U and Th can be improved irradiating the sample inside a Cd capsule, reducing the thermal neutron incidence on the sample and, therefore, diminishing the activation of possible interfering nuclides. In this study the optimal irradiation and counting conditions were established for U and Th determination in fossil teeth and soil. (author)

  20. Determination of specific alpha-emitting radionuclides (uranium, plutonium, thorium and polonium) in water using [Ba+Fe]-coprecipitation method.

    Science.gov (United States)

    Suarez-Navarro, J A; Pujol, Ll; Suarez-Navarro, M J

    2017-09-23

    The indicative dose (ID) is one of the parameters established in the current European directive for water intended for human consumption. To determine the ID, it is necessary to know the activity concentration of: (238)U, (234)U, (226)Ra, (210)Po, (239,240)Pu and (241)Am. The existing methods to determine these radionuclides involve complex radiochemical separations (ionic exchange columns, extraction chromatography, etc.), followed by measurements with a semiconductor detector, laboratory procedures that are time-consuming and costly. As a lower cost alternative that reduces measuring and preparation times, avoids the need for a self-absorption correction and the use of tracers, and above all that can be used in any laboratory, methods based on liquid-liquid extraction and selective co-precipitation were developed. These methodologies offer high separation recovery and selectivity, and the measurements are made using a gas proportional counter or a solid ZnS(Ag) scintillation counter. The separation factor ranged between 91.4% and 100.0% for all alpha-emitting radionuclides across the different methods. The activity concentration for each method was computed through linear equations that represent the relationship between the activity and selectivity of the different alpha-emitting radionuclides. This mathematical procedure simplifies the radiochemical separations and provides more accurate activity concentrations. The results of the internal and external validation studies proved that the proposed method is suitable for determining (241)Am, (226)Ra, uranium, plutonium, thorium and (210)Po in water samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A dihydrazone based fluorescent probe for selective determination of Al{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Pratap Singh, Divya; Singh, Vinod P., E-mail: singvp@yahoo.co.in

    2014-11-15

    A highly selective fluorescent sensor N,N′-bis((2-hydroxynaphthalen-1-yl)methylene) oxalohydrazide (H{sub 2}ohn) for the determination of Al{sup 3+} ions was synthesized and characterized by different physico-chemical and spectroscopic techniques. The single crystal structure of H{sub 2}ohn receptor has also been reported. The H{sub 2}ohn shows an enhanced fluorescence in the presence of Al{sup 3+} ions in ethanol–water (2:3 v/v) solution. Other cations viz. Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Mn{sup 2+}, Fe{sup 3+}, Co{sup 2+}, Ni{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, Pb{sup 2+}, Cd{sup 2+} and Hg{sup 2+} show no appreciable change in fluorescence intensity. The binding mode of H{sub 2}ohn receptor with Al{sup 3+} was studied by UV–visible, fluorescence and {sup 1}H NMR titrations. The receptor acts as a dibasic hexadentate ligand and interacts with two Al{sup 3+} ions with a high binding constant K{sub B}=2.62×10{sup 11} M{sup −2}. The lowest detection limit for Al{sup 3+} complex of H{sub 2}ohn was determined to be 8.56×10{sup −10} M. The structures of H{sub 2}ohn and its Al(III) complex were also optimized by DFT calculations. - Highlights: • A dihydrazone based fluorescent sensor is synthesized. • Characterized by IR, NMR, UV−visible and mass spectral analysis. • The receptor serves as a selective fluorescent sensor for Al{sup 3+} over other cations. • The sensing property is monitored by UV−visible, fluorescence and NMR spectroscopy. • A high binding constant of the receptor with Al{sup 3+} is reported here.

  2. 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.

  3. Determination of elemental impurities and U and O isotopic compositions with a view to identify the geographical and industrial origins of uranium ore concentrates

    Science.gov (United States)

    Salaun, A.; Hubert, A.; Pointurier, F.; Aupiais, J.; Pili, E.; Richon, P.; Fauré, A.; Diallo, S.

    2012-12-01

    First events of illicit trafficking of nuclear and radiological materials occurred 50 years ago. Nuclear forensics expertise are aiming at determining the use of seized material, its industrial history and provenance (geographical area, place of production or processing), at assisting in the identification and dismantling of illicit trafficking networks. This information is also valuable in the context of inspections of declared facilities to verify the consistency of operator's declaration. Several characteristics can be used to determine the origin of uranium ore concentrates such as trace elemental impurity patterns (Keegan et al., 2008 ; Varga et al., 2010a, 2010b) or uranium, oxygen and lead isotopic compositions (Tamborini et al., 2002a, 2002b ; Wallenius et al., 2006; Varga et al., 2009). We developed analytical procedures for measuring the isotopic compositions of uranium (234U/238U and 235U/238U) and oxygen (18O/16O) and levels of elemental impurities (e.g. REE, Th) from very small amounts of uranium ore concentrates (or yellow cakes). Micrometer particles and few milligrams of material are used for oxygen isotope measurements and REE determination, respectively. Reference materials were analyzed by mass spectrometry (TIMS, SF-ICP-MS and SIMS) to validate testing protocols. Finally, materials of unknown origin were analyzed to highlight significant differences and determine whether these differences allow identifying the origin of these ore concentrates. References: Keegan, E., et al. (2008). Applied Geochemistry 23, 765-777. Tamborini, G., et al. (2002a). Analytical Chemistry 74, 6098-6101. Tamborini, G., et al. (2002b). Microchimica Acta 139, 185-188. Varga, Z., et al. (2009). Analytical Chemistry 81, 8327-8334. Varga, Z., et al. (2010a). Talanta 80, 1744-1749. Varga, Z., et al. (2010b). Radiochimica Acta 98, 771-778 Wallenius, M., et al. (2006). Forensic Science International 156, 55-62.

  4. 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.

  5. Solvent extraction separation and spectrographic determination of palladium, rhodium and ruthenium in uranium; Determinacion espectrografica de paladio, rodio y rutenio en uranio, mediante separacion previa por extraccion

    Energy Technology Data Exchange (ETDEWEB)

    Capdevilla, C.; Alduan, F. A.

    1980-07-01

    The determination of Pd, Rh and Ru in uranium at low ppm level, using solvent extraction has been studied. BPHA, TNOA, TOPO and TBP have been tried as complexing agents; TBP In hexane and 5 M nitric acid medium provides a virtually quantitative extraction. The layer containing the impurities is collected Into graphite powder, and this powder is analysed spectro graphically using carrier destination method with % CuF{sub 2} as a carrier. (Author) 11 refs.

  6. Study on fluorescence properties of carbogenic nanoparticles and their application for the determination of ferrous succinate

    Energy Technology Data Exchange (ETDEWEB)

    Sun Wen [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); Du Yingxiang, E-mail: du_yingxiang@126.co [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China) and Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China) and Key Laboratory of Modern Chinese Medicines, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China); Wang Yunqing [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

    2010-08-15

    A new type of fluorescent nanomaterial named carbogenic nanoparticles (NPs) has drawn considerable attention recently. In this study, we adopted a direct and simple synthetic method to produce the carbogenic NPs and investigated the fluorescence properties of the as-prepared carbogenic NPs in detail. It was found that the fluorescence of carbogenic NPs was stable with the variance of environmental conditions such as pH, temperature and UV irradiation. More interestingly, we found carbogenic NPs exhibited high selectivity and sensitivity towards ferric ions. Under optimum conditions, a good linear relationship could be obtained between the fluorescence intensity and concentration of ferric ions in the range of 5.0x10{sup -5}-5.0x10{sup -4} mol L{sup -1}, and the limit of detection is 11.2 {mu}mol L{sup -1}. Based on the fluorescence quenching of carbogenic NPs, a rapid and specific quantitative method was proposed for the determination of ferrous succinate. The content of ferrous succinate in commercial tablets determined by the present method was agreed with the spectrophotometric method results and the reproducibility and the recovery of the proposed method were satisfactory.

  7. A Fluorescence-Based Method for Rapid and Direct Determination of Polybrominated Diphenyl Ethers in Water

    Directory of Open Access Journals (Sweden)

    Huimei Shan

    2015-01-01

    Full Text Available A new method was developed for rapid and direct measurement of polybrominated diphenyl ethers (PBDEs in aqueous samples using fluorescence spectroscopy. The fluorescence spectra of tri- to deca-BDE (BDE 28, 47, 99, 153, 190, and 209 commonly found in environment were measured at variable emission and excitation wavelengths. The results revealed that the PBDEs have distinct fluorescence spectral profiles and peak positions that can be exploited to identify these species and determine their concentrations in aqueous solutions. The detection limits as determined in deionized water spiked with PBDEs are 1.71–5.82 ng/L for BDE 28, BDE 47, BDE 190, and BDE 209 and 45.55–69.95 ng/L for BDE 99 and BDE 153. The effects of environmental variables including pH, humic substance, and groundwater chemical composition on PBDEs measurements were also investigated. These environmental variables affected fluorescence intensity, but their effect can be corrected through linear additivity and separation of spectral signal contribution. Compared with conventional GC-based analytical methods, the fluorescence spectroscopy method is more efficient as it only uses a small amount of samples (2–4 mL, avoids lengthy complicated concentration and extraction steps, and has a low detection limit of a few ng/L.

  8. Determination of the shell growth direction during the formation of silica microcapsules by confocal fluorescence microscopy

    NARCIS (Netherlands)

    Wijk, J. van; Salari, J.W.O.; Meuldijk, J.; Klumperman, B.

    2015-01-01

    A novel procedure was developed to determine the direction of silica growth during the formation of a silica shell around aqueous microdroplets in water-in-oil Pickering emulsions. Two fluorescently labeled silica precursors were added consecutively and the resulting microcapsules were visualized vi

  9. A sensitive fluorescence quenching method for determination of bismuth with tiron

    Energy Technology Data Exchange (ETDEWEB)

    Taher, Mohammad Ali; Rahimi, Mina [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Fazelirad, Hamid, E-mail: hamidfazelirad@gmail.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Department of Chemistry, Science and Research Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of); Young Researchers Society, Shahid Bahonar University of Kerman, P.O. Box 76175-133, Kerman (Iran, Islamic Republic of)

    2014-01-15

    We describe a fluorescence quenching method for determination of bismuth with tiron. The method is based on the reaction of tiron by bismuth(III) in acidic media. The influence of variables such as the pH, type of buffer, tiron concentration, reaction time and temperature were investigated. Under optimized conditions, the fluorescence quenching extent is proportional to the concentration of bismuth for Bi–tiron system at the range 0.13–2.09 μg mL{sup −1} and the detection limit is 0.05 μg mL{sup −1}. The proposed sensor presented good repeatability, evaluated in terms of relative standard deviation (R.S.D.=±0.498%) for 11 replicates. This sensitive, rapid and accurate method has been successfully applied to the determination of trace bismuth(III) in water and hair samples and certified reference materials. -- Highlights: • No previous paper report on use of fluorescence quenching for determination of Bi. • Fluorescence quenching of trion is a sensitive method for determination of Bi(III). • Under the optimum conditions the detection limit is very low (0.05 μg mL{sup −1}). • The procedure is simple and safe and has high tolerance limit to interferences.

  10. Determination of experimental K-shell fluorescence yield for potassium and calcium compounds

    Indian Academy of Sciences (India)

    E Tiraşoğlu; Ö Söğüt

    2008-03-01

    K-shell fluorescence yields were experimentally determined for potassium and calcium compounds using a Si(Li) X-ray detector system (FWHM=5.96 keV at 160 eV). The samples were excited by 5.96 keV photons produced by a 55Fe radioisotope source. The experimental values are systematically lower than the theoretical values.

  11. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  12. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  13. 77 FR 12880 - Uranium From Russia

    Science.gov (United States)

    2012-03-02

    ... COMMISSION Uranium From Russia Determination On the basis of the record \\1\\ developed in the subject five... investigation on uranium from Russia would be likely to lead to continuation or recurrence of material injury to... Publication 4307 (February 2012), entitled Uranium from Russia: Investigation No. 731-TA-539-C (Third...

  14. Uranium, depleted uranium, biological effects; Uranium, uranium appauvri, effets biologiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

  15. Optimized and validated spectrophotometric method for the determination of uranium(VI) via complexation with meloxicam

    Energy Technology Data Exchange (ETDEWEB)

    Lutfullah [Department of Chemistry, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh (India)], E-mail: lutfullah786@gmail.com; Alam, Mohd Noor; Rahman, Nafisur; Azmi, Syed Najmul Hejaz [Department of Chemistry, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh (India)

    2008-06-30

    An optimized and validated spectrophotometric method has been developed for the determination of uranyl ion in the presence of other metal ions. The method is based on the chelation of uranyl ion with meloxicam via {beta}-diketone moiety to produce a yellow colored complex, which absorbs maximally at 398 nm. Beer's law is obeyed in the concentration range of 5-60 {mu}g/mL with apparent molar absorptivity and Sandell's sensitivity of 5.02 x 10{sup 4} L/mol/cm and 0.1 {mu}g/cm{sup 2}/0.001 absorbance unit, respectively. The method has been successfully applied for the determination of uranyl ion in synthetic mixture and soil samples. Results of analysis were statistically compared with those obtained by Currah's spectrophotometric method showing acceptable recovery and precision.

  16. High-order derivative spectrophotometric determination of uranium in a cationic micellar medium

    Energy Technology Data Exchange (ETDEWEB)

    Agnihotri, N.K.; Singh, V.K.; Singh, H.B. [Delhi Univ. (India). Dept. of Chemistry

    1995-06-01

    A derivative spectrophotometric method is developed for the determination of U{sup VI} with 1,4-dihydroxy-9,10-anthracenedione in the presence of cetylpyridinium chloride. The 1:1 complex at pH 5.6 shows maximum absorbance at 600 nm; Beer`s law is obeyed in the range 4.76 x 10{sup -1}-19.04 {mu}g ml{sup -1}. The molar absorption coefficient and Sandell`s sensitivity of the complex are 1.19 x 10{sup 4} l mol{sup -1} cm{sup -1} and 2.00 x 10{sup -2} {mu}g cm{sup -2}, respectively. The proposed method is applied to the determination of U{sup VI} in mixtures containing various amounts of Th{sup IV} and Be{sup II} without pre-separation using second-order derivative absorption plots. A rapid procedure for the simultaneous determination of UO{sub 2}{sup II} and Be{sup II} in binary mixtures is also reported. (author).

  17. Fluorescence quenching method for the determination of catechol with gold nanoparticles and tyrosinase hybrid system

    Institute of Scientific and Technical Information of China (English)

    Martin; M.F.Choi

    2010-01-01

    The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10~(-7)-1.0×10~(-3) mol L~(-1) and a detection limit 1.0×10~(-7) mol L~(-1) of catechol were obtained.o-Quinone intermediate produ...

  18. Foliar Reflectance and Fluorescence Responses for Plants Under Nitrogen Stress Determined with Active and Passive Systems

    Science.gov (United States)

    Middleton, E. M.; McMurtrey, J. E.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; Chappelle, E. W.

    2003-01-01

    Vegetation productivity is driven by nitrogen (N) availability in soils. Both excessive and low soil N induce physiological changes in plant foliage. In 2001, we examined the use of spectral fluorescence and reflectance measurements to discriminate among plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight daily). Three types of steady state laser-induced fluorescence measurements were made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broad irradiance excitation; 2) emission spectra (5 nm resolution) produced by excitation at single wavelengths (280,380 or 360, and 532 nm); and 3) excitation spectra (2 nm resolution), with emission wavelengths fixed at wavelengths centered on selected solar Fraunhofer lines (532,607,677 and 745 nm). Two complementary sets of high resolution (less than 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces: 1) optical properties (350-2500 nm) for reflectance, transmittance, and absorptance; and 2) reflectance spectra (500-1000 nm) acquired with and without a short pass filter at 665 nm to determine the fluorescence contribution to apparent reflectance in the 650-750 spectrum, especially at the 685 and 740 nm chlorophyll fluorescence (ChIF) peaks. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the red edge inflection point. Select optical properties and ChIF parameters were highly correlated for both species. A significant contribution of ChIF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2 - 6% at 740 nm over all N treatments. Discrimination of N treatment

  19. Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Susan; Mohammadzadeh, Darush [Department of Chemistry, University of Birjand, Birjand (Iran); Yamini, Yadollah [Department of Chemistry, Tarbiat Moddars University, Tehran (Iran)

    2003-03-01

    A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 {mu}g L{sup -1} of uranyl. The method was applied to the recovery of uranyl from different water samples. (orig.)

  20. Quantitative determination of Closantel residues in milk by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Stoev, G; Dakova, T; Michailova, A

    1999-06-18

    A HPLC method with fluorescence detection for quantitative determination of Closantel residues in milk has been developed and validated. The proposed cleaning procedure with acetonitrile and acetone extraction, and solid-phase clean-up with Florisil enables concentrations of Closantel below 50 micrograms/l to be determined. The method was shown to be sufficient, precise, accurate, selective and rugged. The method was applied in the regular monitoring of Closantel residues in milk and of the pharmacokinetic behavior of Closantel in sheep.

  1. Ruby fluorescence lifetime measurements for temperature determinations at high (p, T)

    Science.gov (United States)

    Bauer, Johannes D.; Bayarjargal, Lkhamsuren; Winkler, Björn

    2012-06-01

    The lifetime of the ruby R1 fluorescence line was measured as a function of pressure (up to about 20 GPa) and temperature (550 K) in an externally heated diamond anvil cell (DAC). At constant temperatures, the lifetime is increasing linearly with increasing pressure. The slope of the pressure dependence is constant up to a temperature of 450 K and it is decreasing at higher temperatures. At constant pressure, the lifetime is exponentially decreasing with increasing temperature. The (p, T)-dependence can be parametrized by the combination of a linear and an exponential function. This allows an accurate p, T-determination by the combination of fluorescence spectroscopy using Sm2+-doped strontium tetraborate and lifetime measurements of ruby, as the energy of the Sm2+ fluorescence is nearly temperature-independent.

  2. Determination of L-phenylalanine by cucurbit[7]uril sensitized fluorescence quenching method

    Institute of Scientific and Technical Information of China (English)

    Chang Feng Li; Li Ming Du; Hao Wu; Ying Xia Chang

    2011-01-01

    The determination method of L-phenylalanine (LPA) by fluorescence quenching was developed. The assay was based on the combination of the cucurbit[7]uril (CB[7]) with palmatine hydrochloride (PAL) reaction. In the presence of CB[7], the fluorescence of PAL was quenched by LPA which can be employed to detect LPA. Under the optimal conditions, a linear range 3.63 × 10-8-9.68 × 10-6 mol/L and a detection limit 1.27 × 10-8 mol/L of LPA were obtained. The relative standard deviation (R.S.D) was 1.8% obtained from a series of11 standards each containing 6.05 × 10-6 mol/L oLPA. This paper also discusses the mechanism of fluorescence indicator probe.

  3. Fluorescence Quenching Investigation for Janus Green B and used as Probe in Determination of Nucleic Acids

    Institute of Scientific and Technical Information of China (English)

    陈莉华; 刘六战; 沈含熙

    2005-01-01

    Fluorescence quenching of janus green B (JGB) in sodium dodecyl sulfate (SDS) micelle by nucleic acids (DNA) was studied using UV-vis absorption, steady state fluorescence emission methods and lifetime measurements. In the SDS micelle, weak fluorescence of JGB was enhanced, and the maximum emission shifted from 425 to 410 nm. In the presence of DNA, the fluorescence of JGB was quenched. Linear relationships between the fluorescence quenching (F0/F) and concentrations of DNA were observed in the range of 2.4×10-8 to 1.08×10-7mol·L-1 for calf thymus nucleic acids (ct DNA) and 1.9×10-8 to 3.8×10-8 mol·L-1 for fish sperm nucleic acids (fs DNA) when 2.5×10-5 mol·L-1 JGB was employed. The limit detection were 1.3×10-8 mol·L-1 for ct DNA and 6.4×10-9 mol·L-1 for fs DNA. At high DNA concentration, there was a systematic deviation from the Stem-Volmer equation due to the static and dynamic quenching occurring simultaneously. The proposed method was applied to the determination of the nucleic acids in chicken blood extraction and the analytical results were in good agreement with the UV-method.

  4. Carbon quantum dots as fluorescence resonance energy transfer sensors for organophosphate pesticides determination.

    Science.gov (United States)

    Wu, Xiaoli; Song, Yang; Yan, Xu; Zhu, Chengzhou; Ma, Yongqiang; Du, Dan; Lin, Yuehe

    2017-03-07

    Carbon quantum dots (CQDs) obtained from natural organics attract significant attention due to the abundance of carbon sources, varieties of heteroatom doping (such as N, S, P) and good biocompatibility of precursor. In this study, tunable fluorescence emission CQDs originated from chlorophyll were synthesized and characterized. The fluorescence emission can be effectively quenched by gold nanoparticles (Au NPs) via fluorescence resonance energy transfer (FRET). Thiocholine, which was produced from acetylthiocholine (ATC) by the hydrolysis of butyrylcholinesterase (BChE), could cause the aggregation of Au NPs and the corresponding recovery of FRET-quenched fluorescence emission. The catalytic activity of BChE could be irreversibly inhibited by organophosphorus pesticides (OPs), thus, the recovery effect was reduced. By evaluating the fluorescence emission intensity of CQDs, a FRET-based sensing platform for OPs determination was established. Paraoxon was studied as an example of OPs. The sensing platform displayed a linear relationship with the logarithm of the paraoxon concentrations in the range of 0.05-50μgL(-1) and the limit of detection (LOD) was 0.05μgL(-1). Real sample study in tap and river water revealed that this sensing platform was repeatable and accurate. The results indicate that the OP sensor is promising for applications in food safety and environmental monitoring.

  5. On-line solid phase extraction using ion-pair microparticles combined with ICP-OES for the simultaneous preconcentration and determination of uranium and thorium

    Energy Technology Data Exchange (ETDEWEB)

    Yousefi, Seyed Reza; Zolfonoun, Ehsan [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). NFCRS

    2016-07-01

    In this work, after on-line and in-situ solid phase extraction technique was used for the extraction and preconcentration of uranium and thorium from aqueous samples prior to inductively coupled plasma optical emission spectrometry (ICP-OES) determination. In this method, sodium hexafluorophosphate (as an ion-pairing agent) was added to the sample solution containing the cationic surfactant (dodecyltrimethylammonium bromide) and the complexing agent (dibenzoylmethane). A cloudy solution was formed as a result of formation of an ion pair between surfactant and hexafluorophosphate. The solid microparticles were passed through a microcolumn filter and the adsorbed microparticles were subsequently eluted with acid, which was directly introduced into the ICP-OES nebulizer. The main variables affecting the pre-concentration and determination steps of uranium and thorium were studied and optimized. Under the optimum conditions, the enhancement factors of 97 and 95 and the detection limits of 0.52 and 0.21 μg L{sup -1} were obtained for uranium and thorium, respectively.

  6. Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

    Science.gov (United States)

    Zhang, Biao; Li, Mi; Zhang, Xiaowen; Huang, Jing

    2016-07-01

    Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)-0.14903(S/L)-1.80435( R o)0.20023 e -1670.93/T t ( t ≥ 5) to 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)0.01382(S/L)-1.83275( R o)0.25763 e -1654.59/T t ( t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

  7. Cellular localization of uranium in the renal proximal tubules during acute renal uranium toxicity.

    Science.gov (United States)

    Homma-Takeda, Shino; Kitahara, Keisuke; Suzuki, Kyoko; Blyth, Benjamin J; Suya, Noriyoshi; Konishi, Teruaki; Terada, Yasuko; Shimada, Yoshiya

    2015-12-01

    Renal toxicity is a hallmark of uranium exposure, with uranium accumulating specifically in the S3 segment of the proximal tubules causing tubular damage. As the distribution, concentration and dynamics of accumulated uranium at the cellular level is not well understood, here, we report on high-resolution quantitative in situ measurements by high-energy synchrotron radiation X-ray fluorescence analysis in renal sections from a rat model of uranium-induced acute renal toxicity. One day after subcutaneous administration of uranium acetate to male Wistar rats at a dose of 0.5 mg uranium kg(-1) body weight, uranium concentration in the S3 segment of the proximal tubules was 64.9 ± 18.2 µg g(-1) , sevenfold higher than the mean renal uranium concentration (9.7 ± 2.4 µg g(-1) ). Uranium distributed into the epithelium of the S3 segment of the proximal tubules and highly concentrated uranium (50-fold above mean renal concentration) in micro-regions was found near the nuclei. These uranium levels were maintained up to 8 days post-administration, despite more rapid reductions in mean renal concentration. Two weeks after uranium administration, damaged areas were filled with regenerating tubules and morphological signs of tissue recovery, but areas of high uranium concentration (100-fold above mean renal concentration) were still found in the epithelium of regenerating tubules. These data indicate that site-specific accumulation of uranium in micro-regions of the S3 segment of the proximal tubules and retention of uranium in concentrated areas during recovery are characteristics of uranium behavior in the kidney.

  8. Determining the isotopic compositions of uranium and fission products in radioactive environmental microsamples using laser ablation ICP-MS with multiple ion counters.

    Science.gov (United States)

    Boulyga, Sergei F; Prohaska, Thomas

    2008-01-01

    This paper presents the application of a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS)--a Nu Plasma HR--equipped with three ion-counting multipliers and coupled to a laser ablation system (LA) for the rapid and sensitive determination of the 235U/238U, 236U/238U, 145Nd/143Nd, 146Nd/143Nd, 101Ru/(99Ru+99Tc) and 102Ru/(99Ru+99Tc) isotope ratios in microsamples collected in the vicinity of Chernobyl. Microsamples with dimensions ranging from a hundred mum to about 1 mm and with surface alpha activities of 3-38 mBq were first identified using nuclear track radiography. U, Nd and Ru isotope systems were then measured sequentially for the same microsample by LA-MC-ICP-MS. The application of a zoom ion optic for aligning the ion beams into the ion counters allows fast switching between different isotope systems, which enables all of the abovementioned isotope ratios to be measured for the same microsample within a total analysis time of 15-20 min (excluding MC-ICP-MS optimization and calibration). The 101Ru/(99Ru+99Tc) and 102Ru/(99Ru+99Tc) isotope ratios were measured for four microsamples and were found to be significantly lower than the natural ratios, indicating that the microsamples were contaminated with the corresponding fission products (Ru and Tc). A slight depletion in 146Nd of about 3-5% was observed in the contaminated samples, but the Nd isotopic ratios measured in the contaminated samples coincided with natural isotopic composition within the measurement uncertainty, as most of the Nd in the analyzed samples originates from the natural soil load of this element. The 235U/238U and 236U/238U isotope ratios were the most sensitive indicators of irradiated uranium. The present work yielded a significant variation in uranium isotope ratios in microsamples, in contrast with previously published results from the bulk analysis of contaminated samples originating from the vicinity of Chernobyl. Thus, the 235U/238U ratios measured in ten

  9. Determination of the Residual Anthracene Concentration in Cultures of Haloalkalitolerant Actinomycetes by Excitation Fluorescence, Emission Fluorescence, and Synchronous Fluorescence: Comparative Study

    Directory of Open Access Journals (Sweden)

    Reyna del Carmen Lara-Severino

    2016-01-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are compounds that can be quantified by fluorescence due to their high quantum yield. Haloalkalitolerant bacteria tolerate wide concentration ranges of NaCl and pH. They are potentially useful in the PAHs bioremediation of saline environments. However, it is known that salinity of the sample affects fluorescence signal regardless of the method. The objective of this work was to carry out a comparative study based on the sensitivity, linearity, and detection limits of the excitation, emission, and synchronous fluorescence methods, during the quantification of the residual anthracene concentration from the following haloalkalitolerant actinomycetes cultures Kocuria rosea, Kocuria palustris, Microbacterium testaceum, and 4 strains of Nocardia farcinica, in order to establish the proper fluorescence method to study the PAHs biodegrading capacity of haloalkalitolerant actinobacteria. The study demonstrated statistical differences among the strains and among the fluorescence methods regarding the anthracene residual concentration. The results showed that excitation and emission fluorescence methods performed very similarly but sensitivity in excitation fluorescence is slightly higher. Synchronous fluorescence using Δλ=150 nm is not the most convenient method. Therefore we propose the excitation fluorescence as the fluorescence method to be used in the study of the PAHs biodegrading capacity of haloalkalitolerant actinomycetes.

  10. Determination of ammonium on an integrated microchip with LED-induced fluorescence detection

    Institute of Scientific and Technical Information of China (English)

    Shuhua Xue; Katsumi Uchiyama; Hai-fang Li

    2012-01-01

    A simply fabricated microfluidic device integrated with a fluorescence detection system has been developed for on-line determination of ammonium in aqueous samples.A 365-nm light-emitting diode(LED)as an excitation source and a minor band pass filter were mounted into a polydimethylsiloxane(PDMS)-based microchip for the purpose of miniaturization of the entire analytical system.The ammonium sample reacted with o-phthaldialdehyde(OPA)on-chip with sodium sulfite as reducing reagent to produce a fluorescent isoindole derivative,which can emit fluorescence signal at about 425 nm when excited at 365 nm.Effects of pH,flow rate of solutions,concentrations of OPA-reagent,phosphate and sulfite salt were investigated.The calibration curve of ammonium in the range of 0.018-1.8 μg/mL showed a good linear relationship with R2 =0.9985,and the detection limit was(S/N =3)3.6 × 10-4 μg/mL.The relative standard deviation was 2.8%(n =11)by calculating at 0.18 μg/mL ammonium for repeated detection.The system was applied to determine the ammonium concentration in rain and river waters,even extent to other analytes fluorescence detection by the presented device.

  11. ZnSe quantum dots based fluorescence quenching method for determination of paeoniflorin

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhi [Center of Analysis, Guangdong Medical College, Dongguan 523808 (China); School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Chen, Jiayi; Liang, Qiaowen [School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Wu, Dudu [Center of Analysis, Guangdong Medical College, Dongguan 523808 (China); Zeng, Yuaner, E-mail: zengyuaner@126.com [School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Jiang, Bin, E-mail: gzjiangbin@hotmail.com [School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China)

    2014-01-15

    Water soluble ZnSe quantum dots (QDs) modified by mercaptoacetic acid (MAA) were used to determinate paeoniflorin in aqueous solutions by the fluorescence spectroscopic technique. The results showed that the fluorescence of the modified ZnSe QDs could be quenched by paeoniflorin effectively in physiological buffer solution. The optimum fluorescence intensity was found to be at incubation time 10 min, pH 7.0 and temperature 25 °C. Under the optimal conditions, the detection limit of paeoniflorin was 7.30×10{sup −7} mol L{sup −1}. Moreover, the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant K{sub q} (1.02×10{sup 13} L mol{sup −1} s{sup −1}). -- Highlights: • The fluorescence intensity of ZnSe QDs could be quenched by paeoniflorin. • Foreign substance showed insignificant effect for determination of paeoniflorin. • The quenching mechanism was discussed to be a static quenching procedure.

  12. Spectrophotometric determination of uranium with arsenazo previous liquid-liquid extraction and colour development in organic medium; Determinacion espectrofotometrica de uranio con arsenazo, previa extraccion y desarrollo del color en medio organico

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Delgado, F.; Vera Palomino, J.; Petrement Eguiluz, J. C.

    1964-07-01

    The determination of uranium with arsenazo is hindered by a great number of cation which form stable complexes with the reactive and may given rise to serious interferences. By studying the optimum conditions of uranium the extraction be means of tributylphosphate solutions dissolved in methylisobuthylketone, under conditions for previous masking of the interfering cations, an organic extract was obtained containing all the uranium together with small amounts of iron. The possible interference derived from the latter element is avoided by reduction with hydroxylammoniumchlorid followed by complex formation of the Fe(II)-ortophenantroline compound in alcoholic medium. (Author) 17 refs.

  13. Rapid fluorometric determination of perfluorooctanoic acid by its quenching effect on the fluorescence of quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi; Huang, Aizhen; Wang, Nan, E-mail: nwang@hust.edu.cn; Zheng, Guan; Zhu, Lihua

    2015-05-15

    Analysis of perfluorooctanoic acid (PFOA) usually requires a combination of high-performance liquid chromatography and mass spectrometry, which is expensive and time-consuming. In the present work, water-soluble CdS quantum dots (QDs) were employed to develop a simple and rapid fluorometric method for the determination of PFOA. Strongly fluorescent CdS QDs were prepared by using 3-mercaptopropionic acid (MPA) as a stabilizer. It was observed that PFOA strongly quenched the fluorescence emission of the MPA-CdS QDs because PFOA promotes the aggregation of MPA-CdS QDs through a fluorine–fluorine affinity interaction. Under optimum conditions, the fluorescence intensity of MPA-CdS QDs was observed to decrease linearly with an increase in the concentration of PFOA from 0.5 to 40 μmol L{sup −1}, with a limit of detection of 0.3 μmol L{sup −1}. This new method was successfully implemented for the analysis of PFOA-spiked textile samples, with recoveries ranging from 95% to 113%. - Highlights: • PFOA significantly quenched the fluorescence emission of quantum dots (QDs). • A rapid and simple fluorescence sensor was proposed for determining PFOA by QDs. • PFOA determination could be completed within approximately 10 min. • The developed method had a working range of 0.5 to 40 μmol L{sup −1} and a detection limit of 0.3 μmol L{sup −1}.

  14. Fluorescence microscopy methods for determining the viability of bacteria in association with mammalian cells.

    Science.gov (United States)

    Johnson, M Brittany; Criss, Alison K

    2013-09-05

    Central to the field of bacterial pathogenesis is the ability to define if and how microbes survive after exposure to eukaryotic cells. Current protocols to address these questions include colony count assays, gentamicin protection assays, and electron microscopy. Colony count and gentamicin protection assays only assess the viability of the entire bacterial population and are unable to determine individual bacterial viability. Electron microscopy can be used to determine the viability of individual bacteria and provide information regarding their localization in host cells. However, bacteria often display a range of electron densities, making assessment of viability difficult. This article outlines protocols for the use of fluorescent dyes that reveal the viability of individual bacteria inside and associated with host cells. These assays were developed originally to assess survival of Neisseria gonorrhoeae in primary human neutrophils, but should be applicable to any bacterium-host cell interaction. These protocols combine membrane-permeable fluorescent dyes (SYTO9 and 4',6-diamidino-2-phenylindole [DAPI]), which stain all bacteria, with membrane-impermeable fluorescent dyes (propidium iodide and SYTOX Green), which are only accessible to nonviable bacteria. Prior to eukaryotic cell permeabilization, an antibody or fluorescent reagent is added to identify extracellular bacteria. Thus these assays discriminate the viability of bacteria adherent to and inside eukaryotic cells. A protocol is also provided for using the viability dyes in combination with fluorescent antibodies to eukaryotic cell markers, in order to determine the subcellular localization of individual bacteria. The bacterial viability dyes discussed in this article are a sensitive complement and/or alternative to traditional microbiology techniques to evaluate the viability of individual bacteria and provide information regarding where bacteria survive in host cells.

  15. Uranium potentiometer determination in inactive atmosphere with ferric sulfate; Determinacion poteniometrica de uranio en atmosfera inerte con sulfato ferrico

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R.; Alonso Lopez, J.

    1956-07-01

    Potentiometric titration of Uranium with (SO{sub 4}){sub 3} Fe{sub 2}, using Cd as reducing agent has been studied; acidity and sensibility of this reaction are fixed. This method yields good results for uranite group, removing previously phosphate by ion exchange with Amberlite IR-120. (Author)

  16. Automated determination of uranium(VI) at ultra trace levels exploiting flow techniques and spectrophotometric detection using a liquid waveguide capillary cell.

    Science.gov (United States)

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2010-05-01

    Rapid and fully automated multisyringe flow-injection analysis (MSFIA) with a multi-pumping flow system (MPFS) coupled to a long path-length liquid waveguide capillary cell (LWCC) is proposed for the determination of uranium(VI) at ultra trace levels. On-line separation and pre-concentration of uranium is carried out by means of a TRU resin. After elution, uranium(VI) is spectrophotometrically detected after reaction with arsenazo-III. Combination of the MSFIA and MPFS techniques with the TRU-resin enables the analysis to be performed in a short time, using large sample volumes and achieving high selectivity and sensitivity levels. A detection limit of 12.6 ng L(-1) (ppt) is reached for a 100-mL sample volume. The versatility of the proposed method also enables pre-concentration of variable sample volumes, enabling application of the analysis to a wide concentration range. Reproducibility of better than 5% and a resin durability of 40 injections should be emphasized. The developed method was successfully applied to different types of environmental sample matrices with recoveries between 95 and 108%.

  17. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates

    Energy Technology Data Exchange (ETDEWEB)

    Mas, J.L., E-mail: ppmasb@us.es [Dpto. Fisica Aplicada I, EPS, Universidad de Sevilla, 41012 Sevilla (Spain); Villa, M. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain); Hurtado, S. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Garcia-Tenorio, R. [Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Polluted sediment and NORM samples. Black-Right-Pointing-Pointer An efficient yet fast process allowing multi-parametric determinations in <3 days. Black-Right-Pointing-Pointer Trace element concentrations, Pb, Th and U isotope ratios with a single instrument. - Abstract: This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and {sup 206}Pb/{sup 207}Pb/{sup 208}Pb, {sup 238}U/{sup 234}U and {sup 232}Th/{sup 230}Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA{sup Registered-Sign} extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

  18. Functionalized gold nanoclusters as fluorescent labels for immunoassays: Application to human serum immunoglobulin E determination.

    Science.gov (United States)

    Alonso, María Cruz; Trapiella-Alfonso, Laura; Fernández, José M Costa; Pereiro, Rosario; Sanz-Medel, Alfredo

    2016-03-15

    A quantitative immunoassay for the determination of immunoglobulin E (IgE) in human serum using gold nanoclusters (AuNCs) as fluorescent label was developed. Water soluble AuNCs were synthesized using lipoic acid and then thoroughly characterized. The obtained AuNCs have a particle size of 2.7 ± 0.1 nm and maximum fluorescence emission at 710 nm. The synthesized AuNCs showed very good stability of the fluorescent signal with light exposure and at neutral and slightly basic media. A covalent bioconjugation of these AuNCs with the desired antibody was carried out by the carbodiimide reaction. After due optimization of such bioconjugation reaction, a molar ratio 1:3 (antibody:AuNCs) was selected. The bioconjugate maintained an intense luminescence emission, slightly red-shifted as compared to the free AuNCs. Two typical immunoassay configurations, competitive and sandwich, were assayed and their performance for IgE determination critically compared. After the different immunoassay steps were accomplished, the fluorescence emission of the bioconjugate was measured. While the sandwich format provided a detection limit (DL) of 10 ng/mL and a linear range between 25 and 565 ng/mL of IgE, the competitive format revealed a DL of 0.2 ng/mL with a linear range between 0.3 and 7.1 ng/mL The applicability of the more sensitive competitive fluorescent immunoassay was assessed by successful analysis of the IgE in human serum and comparison of results with those from a commercial kit. The main advantages of the proposed AuNCs-based fluorimetric method include a low DL and a simple immunoassay protocol involving few reagents.

  19. Liquid chromatographic determination of beta-cyclodextrin derivatives based on fluorescence enhancement after inclusion complexation.

    Science.gov (United States)

    Reeuwijk, H J; Irth, H; Tjaden, U R; Merkus, F W; van der Greef, J

    1993-04-21

    A liquid chromatographic method using fluorescence detection for the determination of beta-cyclodextrin (beta CD) and its derivatives is presented. The chromatographic system is based on size-exclusion chromatography with the addition of the fluorophoric compound 1-naphthol to the mobile phase. Detection is based on fluorescence enhancement caused by the formation of inclusion complexes. By incorporating 10(-4) M 1-naphthol in the mobile phase, detection limits of 90, 27, 370 and 37 pmol were obtained for beta CD, hydroxypropyl-beta CD, trimethyl-beta CD and dimethyl-beta CD, respectively. The method was applied to the determination of dimethyl-beta CD in urine: the minimum detectable concentration was 0.2 microgram/ml after preconcentration of 10 ml of urine.

  20. Rapid determination of ampicillin in bovine milk by liquid chromatography with fluorescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Ang, C.Y.W.; Luo, Wenhong [National Center for Toxicological Research, Jefferson, AR (United States)

    1997-01-01

    A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of ampicillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deproteinized with trichloroacetic acid (TCA) and acetonictrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5, 10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb. 16 refs., 4 figs., 3 tabs.

  1. Bias in the absorption coefficient determination of a fluorescent dye, standard reference material 1932 fluorescein solution

    Energy Technology Data Exchange (ETDEWEB)

    DeRose, Paul C. [Analytical Chemistry Division, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, MD 20899-8394 (United States)]. E-mail: paul.derose@nist.gov; Kramer, Gary W. [Analytical Chemistry Division, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, MD 20899-8394 (United States)

    2005-06-15

    The absorption coefficient of standard reference material[registered] (SRM[registered]) 1932, fluorescein in a borate buffer solution (pH=9.5) has been determined at {lambda}=488.0, 490.0, 490.5 and 491.0 nm using the US national reference UV/visible spectrophotometer. The purity of the fluorescein was determined to be 97.6% as part of the certification of SRM 1932. The solution measured was prepared gravimetrically by diluting SRM 1932 with additional borate buffer. The value of the absorption coefficient was corrected for bias due to fluorescence that reaches the detector and for dye purity. Bias due to fluorescence was found to be on the order of -1% for both monochromatic and polychromatic (e.g., diode-array based) spectrophotometers.

  2. Determination of uranium transfer factors from soils contaminated with natural uranium along the Vereinigten Mulde in Zwickau; Bestimmung von Transferfaktoren von Uran aus natuerlich belasteten Boeden entlang der Zwickauer und Vereinigten Mulde

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Andreas

    2011-07-01

    According to IAEA the food chain soil-plants-human is the predominant radionuclide ingestion path. The consumption of contaminated vegetarian food causes a continuous radiation exposure. In this context the problem of contaminated meadows in the Zwickauer and Vereinigten Mulde that is used for agriculture is of predominant interest. In this area intensive uranium mining has caused severe environmental contamination. The agricultural crop land and the grass land were studied with respect to the radionuclides U-238 and U-234. Following the radiochemical separation using ion chromatography the samples were analyzed by alpha-spectrometry. Compared to non-contaminated areas significant specific activities were measured. The transfer factors of the radionuclides U-238 and U-234 were determined for different plant parts. The transfer factors decrease with increasing radioactive contamination of the soils.

  3. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    OpenAIRE

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M B

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn hydrolysis to salicylic acid. With the method for free acetylsalicylic acid and salicylic acid, recovery was 95-98␏or acetylsalicylic acid added to foods and 92-102␏or salicylic acid. Recovery of a...

  4. Determination of gamma-ray widths in $^{15}$N using nuclear resonance fluorescence

    OpenAIRE

    Szücs, T.; Bemmerer, D.; Caciolli, A.; Fülöp, Zs.; Massarczyk, R.; Michelagnoli, C.; Reinhardt, T. P.; Schwengner, R.; Takács, M. P.; Ur, C. A.; Wagner, A.; Wagner, L.

    2015-01-01

    The stable nucleus $^{15}$N is the mirror of $^{15}$O, the bottleneck in the hydrogen burning CNO cycle. Most of the $^{15}$N level widths below the proton emission threshold are known from just one nuclear resonance fluorescence (NRF) measurement, with limited precision in some cases. A recent experiment with the AGATA demonstrator array determined level lifetimes using the Doppler Shift Attenuation Method (DSAM) in $^{15}$O. As a reference and for testing the method, level lifetimes in $^{1...

  5. Phase Structures of Microemulsions Determined by the Steady-State Fluorescence Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The steady-state fluorescence method has been tentatively used to determine the phase structures of microemulsion systems consisting of cetyltrimethylammonium bromide (CTAB), n-butanol (n-C4H9OH), octane (n-C5H18), and water. The excimer/monomer intensity ratio (Ie/Im) of pyrene has demonstrated that the various structures in the microemulsion phase region can be distinguished. The results are consistent with electrical conductivity data already reported.

  6. A novel fluorescence derivatization method combined with HPLC for determining the activities of endogenous caspase.

    Science.gov (United States)

    Liu, Jiachi; Lu, Ye; Liang, Jianying

    2012-11-07

    A novel fluorescence derivatization method combined with HPLC was developed to detect the activity of caspase-3 and -8 in two cell lines (Hela cells and A549 cells) which were activated by low temperature-assisted ultraviolet irradiation (LT-UV), mitomycin C (MMC) and camptothecin during the apoptosis, respectively. Two peptide substrates for either caspase-3 or -8 were designed, of which peptide fragments were obtained by enzymatic modification, followed by fluorescence derivatization. A single fluorescent product was formed when a peptide was heated at 120 °C for 10 min in a neutral aqueous medium (pH 7.0) containing catechol, sodium periodate and sodium borate. Commercial kits for detecting the activity of caspase-3 and -8 were used as a control. The relative activity of the caspases detected by fluorescence derivatization was similar to that obtained by commercial kits, which indicated that the novel method is reliable. The activity assays of recombinant human caspases showed that the novel method provided higher selectivity than that of commercial kits, which proved it to be more accurate for determining the activity of caspases in apoptosis.

  7. Determination of Dynamics of Plant Plasma Membrane Proteins with Fluorescence Recovery and Raster Image Correlation Spectroscopy.

    Science.gov (United States)

    Laňková, Martina; Humpolíčková, Jana; Vosolsobě, Stanislav; Cit, Zdeněk; Lacek, Jozef; Čovan, Martin; Čovanová, Milada; Hof, Martin; Petrášek, Jan

    2016-04-01

    A number of fluorescence microscopy techniques are described to study dynamics of fluorescently labeled proteins, lipids, nucleic acids, and whole organelles. However, for studies of plant plasma membrane (PM) proteins, the number of these techniques is still limited because of the high complexity of processes that determine the dynamics of PM proteins and the existence of cell wall. Here, we report on the usage of raster image correlation spectroscopy (RICS) for studies of integral PM proteins in suspension-cultured tobacco cells and show its potential in comparison with the more widely used fluorescence recovery after photobleaching method. For RICS, a set of microscopy images is obtained by single-photon confocal laser scanning microscopy (CLSM). Fluorescence fluctuations are subsequently correlated between individual pixels and the information on protein mobility are extracted using a model that considers processes generating the fluctuations such as diffusion and chemical binding reactions. As we show here using an example of two integral PM transporters of the plant hormone auxin, RICS uncovered their distinct short-distance lateral mobility within the PM that is dependent on cytoskeleton and sterol composition of the PM. RICS, which is routinely accessible on modern CLSM instruments, thus represents a valuable approach for studies of dynamics of PM proteins in plants.

  8. Determining the ice-binding planes of antifreeze proteins by fluorescence-based ice plane affinity.

    Science.gov (United States)

    Basu, Koli; Garnham, Christopher P; Nishimiya, Yoshiyuki; Tsuda, Sakae; Braslavsky, Ido; Davies, Peter

    2014-01-15

    Antifreeze proteins (AFPs) are expressed in a variety of cold-hardy organisms to prevent or slow internal ice growth. AFPs bind to specific planes of ice through their ice-binding surfaces. Fluorescence-based ice plane affinity (FIPA) analysis is a modified technique used to determine the ice planes to which the AFPs bind. FIPA is based on the original ice-etching method for determining AFP-bound ice-planes. It produces clearer images in a shortened experimental time. In FIPA analysis, AFPs are fluorescently labeled with a chimeric tag or a covalent dye then slowly incorporated into a macroscopic single ice crystal, which has been preformed into a hemisphere and oriented to determine the a- and c-axes. The AFP-bound ice hemisphere is imaged under UV light to visualize AFP-bound planes using filters to block out nonspecific light. Fluorescent labeling of the AFPs allows real-time monitoring of AFP adsorption into ice. The labels have been found not to influence the planes to which AFPs bind. FIPA analysis also introduces the option to bind more than one differently tagged AFP on the same single ice crystal to help differentiate their binding planes. These applications of FIPA are helping to advance our understanding of how AFPs bind to ice to halt its growth and why many AFP-producing organisms express multiple AFP isoforms.

  9. Determination of protease subsite preference on SPOT peptide array by fluorescence quenching-based assay.

    Science.gov (United States)

    Kim, Do-Hyun; Shin, Dong-Sik; Lee, Yoon-Sik

    2012-06-01

    A peptide SPOT array was synthesized on a glass chip and used to determine protease subsite preference. To synthesize a peptide array for positional scanning, the ratio of the isokinetic concentration was determined for every Fmoc-amino acid except Cys. Based on this ratio, a peptide array consisting of Dabcyl-X-X-P(2)-Arg-X-X-X-Lys(FITC) (X: equimolar mixture of 19 amino acids, P(2): one of 19 amino acids) was synthesized on a chitosan-grafted glass chip. Subsequently, the peptide substrates on the array were hydrolyzed by thrombin to screen for subsite specificity using a fluorescence quenching-based assay. The P(2) subsite specificity of thrombin was screened by the fluorescence images obtained after hydrolysis. Pro at the P(2) subsite showed the highest specificity for thrombin based on both the fluorescence quenching-based assay and the solution phase assay. From these results, we confirmed that our mixture-based peptide SPOT array format on the chitosan-grafted glass chips could be used to determine protease subsite preference.

  10. Very long hillslope transport timescales determined from uranium-series isotopes in river sediments from a large, tectonically stable catchment

    Science.gov (United States)

    Suresh, P. O.; Dosseto, A.; Hesse, P. P.; Handley, H. K.

    2014-10-01

    The uranium-series isotopic compositions of soils and sediments evolve in response to time and weathering conditions. Therefore, these isotopes can be used to constrain the timescales of river sediment transport. Catchment evolution depends on the sediment dynamic timescales, on which erosion imparts a major control. Erosion rates in tectonically stable catchments are expected to be lower than those in tectonically active catchments, implying longer sediment residence times in tectonically stable catchments. Mineralogical, elemental and isotopic data are presented for modern channel sediments, alluvial and colluvial deposits from the Murrumbidgee River, a large catchment in the passive margin highlands of south-eastern Australia and three of its tributaries from the headwaters to the alluvial plain. Low variability in Si-based Weathering Index indicates that there is little chemical weathering occurring in the Murrumbidgee River during sediment transport. However, quartz content increases and plagioclase content decreases downstream, indicating progressive mineralogical sorting and/or physical comminution with increasing transport distance. U-series isotopic ratios in the Murrumbidgee River trunk stream sediments show no systematic downstream variation. The weathering ages of sediments within the catchment were determined using a loss-gain model of U-series isotopes. Modern sediments from a headwater tributary, the Bredbo River at Frogs Hollow, have a weathering age of 76 ± 30 kyr but all other modern channel sediments from the length of the Murrumbidgee River and its main tributaries have weathering ages ∼400 ± 180 kyr. The two headwater colluvial deposits have weathering ages of 57 ± 13 and 47 ± 11 kyr, respectively. All the alluvial deposits have weathering ages similar to those of modern sediments. No downstream trend in weathering age is observed. Together with the soil residence time of up to 30 kyr for ridge-top soils at Frogs Hollow in the upper

  11. Determination of depleted uranium in fish: validation of a confirmatory method by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS).

    Science.gov (United States)

    D'Ilio, S; Violante, N; Senofonte, O; Petrucci, F

    2007-08-06

    Depleted uranium (DU) is a by-product of the uranium enrichment process for nuclear fuel. According to the Commission Decision 2002/657/EC, a confirmatory method for the quantification of DU in freeze-dried fish was developed by isotope ratio dynamic reaction cell inductively coupled plasma-mass spectrometry (IR-DRC-ICP-MS). A preliminary study was performed to determine the following parameters: instrumental detection limit (IDL), isotopic ratio measurement limit (IRML), percentage of DU (P(DU)) in presence of natural uranium (NU) and limit of quantification (LoQ(DU)). The analyses were carried out by means of IR-DRC-ICP-MS. Ammonia was the reaction gas used for the dynamic reaction cell. In addition, a sector field inductively coupled plasma mass spectrometer (SF-ICP-MS) was employed to calculate the within-laboratory reproducibility. For the confirmatory method the following parameters were determined: (a) trueness; (b) precision; (c) critical concentrations alpha and beta (CC(alpha), CC(beta)); (d) specificity; (e) stability. Trueness was assessed by using the recovery tests. The recovery and within-laboratory reproducibility were determined by fortifying the blank digested solution of dogfish tissue: six aliquots were fortified at 1, 1.5 and 2 times the LOQ(DU) with 25.0, 37.5 and 50.0 ng L(-1) or 4.16, 6.24, 8.32 microg kg(-1) with a recovery of -8.2, +9.5 and +9.6%, respectively and a within-laboratory reproducibility (three analytical run) of 15.5, 8.0 and 11.0%, respectively. The results for the decision limit and the detection capability were: CC(alpha) = 11.69 ng L(-1) and CC(beta) = 19.8 ng L(-1). The digested solutions resulted to be stable during testing time (60 days) and the method can be considered highly specific as well.

  12. Sensitized effect of β-cyclodextrin on the fluorescence in the determination of carbaryl

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-li; TANG Bo

    2004-01-01

    Based on the significant enhancement of fluorescence intensity of carbaryl in inclusion complex, a spetrofluorimetric method with high sensitivity was developed for the determination of carbaryl in aqueous solution. Under the optimum conditions, the complex had excitation and emission maxima at 278 nm and 332 nm, respectively. The linear range of the method was 7.0 ng/ml-1500 ng/ml with a detection limit of 1.2 ng/ml. The proposed method was successfully used to determine quantitatively of carbaryl in cottonseeds.

  13. Sensitive Determination of Uranium in Natural Waters Using UV-Vis Spectrometry After Preconcentration by Ion-Imprinted Polymer-Ternary Complexes.

    Science.gov (United States)

    Bicim, Tulin; Yaman, Mehmet

    2016-07-01

    The main purpose of this study was to achieve a substantial increase in the sensitivity of the uranium determination using UV-Vis spectrometry. To achieve this goal, ion-imprinted polymers were prepared for the uranyl (imprint) ion by the formation of a ternary (salicylaldoxime and 4-vinylpyridine) complex in 2-methoxy ethanol (porogen) following copolymerization with methacrylic acid. The synthesized polymers were characterized by FTIR analysis and thermogravimetric analysis. In the preconcentration step, the optimal pH was determined to be between values of 3.5 and 6.5. The adsorbed UO2(2+) was completely eluted by 10 mL of 3.0 mol L(-1) HClO4. The developed method was applied to uranium (VI) determination in natural water samples. By using the initial volume of 500 mL and final volume of 5 mL, a concentration of 1 μg L(-1) can be determined by applying the developed method in this study.

  14. Simultaneous determination of airborne carbamates in workplace by high performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Li, Hong-Ping; Li, Jen-Hou; Li, Gwo-Chen; Jen, Jen-Fon

    2004-06-17

    A high performance liquid chromatography with fluorescence (HPLC-F) detector was examined to simultaneous determination of airborne carbamates in the workplace of manufactory. The OVS-2 air sampling tube filled with glass fiber filter or quartz fiber and combined filter/XAD-2 were evaluated to collect nine commonly used carbamates (Carbofuran, Isoprocarb, Methomyl, Metolcarb, Thiodicarb, Carbaryl, Oxamyl, Methiocarb, and Prpoxur) from the air of manufactory in high humidity country. After being extracted with acetonitrile from sampling tubes, the carbamates were determined by high performance liquid chromatography with fluorescence detection posterior to on-line derivatization. The collection of carbamates and the recovery of extraction from glass wool fiber in several concentration levels, and from quartz filter were evaluated. The storage stability of carbamates was also tested. Results indicated that the HPLC-fluorescence method offers satisfactory resolution and sensitivity in carbamate analysis. With the glass fiber filter and combined filter/XAD-2, the Carbofuran, Isoprocarb, Methomyl, Metolcarb, and Thiodicarb were stable for a 28-day storage test, Carbaryl and Oxamyl for 14 days, and Methiocarb and Prpoxur for 7 days. All of these pesticides were with detection limit of 3mugm(-3). It is suited for environmental monitoring. The airborne carbamates in different areas of the manufactory were measured.

  15. Critical tonicity determination of sperm using fluorescent staining and flow cytometry

    Energy Technology Data Exchange (ETDEWEB)

    Noiles, E.E.; Ruffing, N.A.; Kleinhans, F.W.; Mark, L.A.; Watson, P.F.; Critser, J.K. (Methodist Hospital, Indianapolis, IN (USA)); Horstman, L. (Purdue Univ., Lafayette, IN (USA). School of Veterinary Medicine); Mazur, P. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    The use of cryopreserved, rather than fresh, mammalian semen for artificial insemination confers several important medical and/or economic advantages. However, current methods for cryopreservation of both human and bovine spermatozoa result in approximately only a 50% survival rate with thawing, obviously reducing the fertilizing capacity of the semen. A primary consideration during the cooling process is to avoid intracellular ice crystal formation with its lethal consequences to the cell. Current techniques achieve this by controlling the cooling rate. Computation of the time necessary for this dehydration, and hence, the cooling rate, is dependent upon knowledge of the water permeability coefficient (L{sub {rho}}) and its activation energy. The fluorophore, 6-carboxyfluoroscein diacetate (CFDA), which is nonfluorescent, readily crosses the intact plasma membrane. Intracellular esterases hydrolyze CFDA to 6-carboxyfluoroscein, a fluorescent, membrane-impermeable fluorophore. Consequently, spermatozoa with intact plasma membranes fluoresce bright green (Garner et. al., 1986), but those with disrupted membranes do not. Therefore, the purpose of this study was to use loss of CFDA fluorescence to determine the osmolality at which 50% of the spermatozoa will swell and lyse (critical tonicity, CT). These data will then be used to determine the L{sub {rho}} and its activation energy for sperm, thus increasing the knowledge available in cellular cryopreservation. 15 refs., 3 figs.

  16. Determination of human albumin in serum and urine samples by constant-energy synchronous fluorescence method.

    Science.gov (United States)

    Madrakian, Tayyebeh; Bagheri, Habibollah; Afkhami, Abbas

    2015-08-01

    A sensitive spectrofluorimetric method using constant-energy synchronous fluorescence technique is proposed for the determination of human albumin without separation. In this method, no reagent was used for enhancement of the fluorescence signal of albumin in the solution. Effects of some parameters, such as energy difference between excitation and emission monochromators (ΔE), emission and excitation slit widths and scan rate of wavelength were studied and the optimum conditions were established. For this purpose factorial design and response surface method were employed for optimization of the effective parameters on the fluorescence signal. The results showed that the scan rate of the wavelength has no significant effect on the analytical signal. The calibration curve was linear in the range 0.1-220.0 µg mL(-1) of albumin with a detection limit of 7.0 × 10(-3)  µg mL(-1). The relative standard deviations (RSD) for six replicate measurements of albumin were calculated as 2.2%, 1.7% and 1.3% for 0.5, 10.0 and 100.0 µg mL(-1) albumin, respectively. Furthermore the proposed method has been employed for the determination of albumin in human serum and urine samples.

  17. Utility of gold nanoparticles in luminescence determination of trovafloxacin: comparison of chemiluminescence and fluorescence detection.

    Science.gov (United States)

    Alarfaj, Nawal A; El-Tohamy, Maha F

    2015-12-01

    Two novel sensitive sequential injection chemiluminescence analysis and fluorescence methods for trovafloxacin mesylate detection have been developed. The methods were based on the enhancement effect of gold nanoparticles on luminol-ferricyanide-trovafloxacin and europium(III)-trovafloxacin complex systems. The optimum conditions for both detection methods were investigated. The chemiluminescence signal was emitted due to the enhanced effect of gold nanoparticles on the reaction of luminol-ferricyanide-trovafloxacin in an alkaline medium. The response was linear over a concentration range of 1.0 × 10(-9) to 1.0 × 10(-2) mol/L (%RSD = 1.3), (n = 9, r = 0.9991) with a detection limit of 1.7 × 10(-10) mol/L (S/N = 3). The weak fluorescence intensity signal of the oxidation complex of europium(III)-trovafloxacin was strongly enhanced by gold nanoparticles and detected at λex = 330 and λem = 540 nm. Fluorescence detection enabled the determination of trovafloxacin mesylate over a linear range of 1.0 × 10(-8) to 1.0 × 10(-3) mol/L (%RSD = 1.2), (n = 6, r = 0.9993) with a detection limit of 3.3 × 10(-9) mol/L. The proposed methods were successfully applied to the determination of the studied drug in its bulk form and in pharmaceutical preparations. The results were treated statistically and compared with those obtained from other reported methods.

  18. Determination of catalyst metal residues in polymers by X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Bichinho, Katia M. [CIENTEC-Fundacao de Ciencia e Tecnologia, Rua Washington Luiz, 675, Porto Alegre, 90010-460 (Brazil); Pires, Gilvan Pozzobon [Instituto de Quimica, Universidade Federal do Rio Grande do Sul (UFRGS) Avenida Bento Goncalves 9500, Porto Alegre, 91501-970 (Brazil); Stedile, Fernanda C. [Instituto de Quimica, Universidade Federal do Rio Grande do Sul (UFRGS) Avenida Bento Goncalves 9500, Porto Alegre, 91501-970 (Brazil); Santos, Joao Henrique Z. dos [Instituto de Quimica, Universidade Federal do Rio Grande do Sul (UFRGS) Avenida Bento Goncalves 9500, Porto Alegre, 91501-970 (Brazil)]. E-mail: jhzds@iq.ufrgs.br; Wolf, Carlos Rodolfo [Ipiranga Petroquimica S.A., Departamento de Desenvolvimento de Produto, Polo Petroquimico do Sul, BR 386, km 419, Triunfo, CEP 95853-000 (Brazil)

    2005-06-30

    Commercial polyethylenes produced by Ziegler-Natta, Philips and metallocene technology were analyzed by X-ray fluorescence spectroscopy. Synthetic standards using wax matrix was shown to be suitable for the calibration curve in comparison to those prepared by milling and grinding virgin polymer mixed with standard metal oxide as matrix. The detection limits obtained for the studied metal in the different polymers were: 12 mg kg{sup -1} for Mg, 0.8 mg kg{sup -1} for Ti, 1.6 mg kg{sup -1} for Cr, 1.2 mg kg{sup -1} for Zr and 1.9 mg kg{sup -1} for V. For comparative reasons, the determination of residual metal content by Rutherford backscattering spectrometry (RBS) and total-reflection X-ray fluorescence spectrometry (TXRF) is also discussed.

  19. Determination of fluorinated quinolone antibacterials by ion chromatography with fluorescence detection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-zhen; ZHANG Zheng-yi; ZHOU Yan-chun; LIU Li; ZHU Yan

    2007-01-01

    For preparing fluorinated quinolone antibiotic medicine locally used in stomatology, simultaneous determination of norfloxacin, ciprofloxacin, and enoxacin was carried out by multiphase ion chromatography with fluorescence detection. Quinolone antibiotics were separated by Dionex OmniPac PAX-500 column with an eluent of 15 mmol/L H2SO4 and 35% methanol (v/v) at a flow-rate of 1.0 ml/min and detected with fluorescence with excitation and emission wave lengths of 347 nm and 420 nm respectively. The detection limits (S/N=3) ofnorfloxacin, ciprofloxacin and enoxacin were 50, 105 and 80 ng/ml respectively. The relative standard deviations of retention time, peak area and peak height were less than 1.1% and good linear relationship resulted.The developed method was applied to pharmaceutical formulations and biological fluids.

  20. An ultrasensitive method for the determination of melamine using cadmium telluride quantum dots as fluorescence probes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiafei; Li, Jin; Kuang, Huiyan; Feng, Lei; Yi, Shoujun; Xia, Xiaodong; Huang, Haowen [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education of China, Hunan University of Science and Technology, Xiangtan 411201 (China); Chen, Yong; Tang, Chunran [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Zeng, Yunlong, E-mail: yunlongzeng1955@126.com [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education of China, Hunan University of Science and Technology, Xiangtan 411201 (China); State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2013-11-13

    Graphical abstract: Melamine takes place of the TGA on the surface of TGA-CdTe QDs with negative charge to form melamine coated QDs changing the surface charge of the QDs, resulting the fluorescence quenched as the QDs aggregation occurred by electrostatic attraction of the two opposite charged nanocrystals. -- Highlights: •An ultrasensitive and selective method for the determination of melamine was developed at pH 11.0. •The selectivity of the method was improved. •The sensitivity of the method enhanced obviously as the CdTe QDs have higher QYs at pH 11. •The sensitivity and linear range for the analysis are size dependent using QDs PL probes. •Melamine takes the place of TGA resulting fluorescence quenched of QDs. -- Abstract: An ultrasensitive and simple method for the determination of melamine was developed based on the fluorescence quenching of thioglycolic acid (TGA) capped CdTe quantum dots (QDs) at pH 11.0. In strong alkaline aqueous solution, the selectivity of the method has been greatly improved due to most heavy metal ions show no interference as they are in the precipitation form or in their anion form. Furthermore, CdTe quantum dots have higher quantum yields at higher pH. The method has a wider concentration range and lower detection limit. The influence factors on the determination of melamine were investigated and the optimum conditions were determined. Under optimum conditions, the fluorescence intensity change of TGA coated CdTe quantum dots was linearly proportional to melamine over a concentration range from 1.0 × 10{sup −11} to 1.0 × 10{sup −5} mol L{sup −1} with a correlation coefficient of 0.9943 and a detection limit of 5 × 10{sup −12} mol L{sup −1}. The mechanism of fluorescence quenching of the QDs has been proposed based on the infrared spectroscopy information and electrophoresis experiments in presence of melamine under alkaline condition. The proposed method was employed to detect trace melamine in milk powder

  1. Determination of the Residual Anthracene Concentration in Cultures of Haloalkalitolerant Actinomycetes by Excitation Fluorescence, Emission Fluorescence, and Synchronous Fluorescence: Comparative Study

    OpenAIRE

    Reyna del Carmen Lara-Severino; Miguel Ángel Camacho-López; Jessica Marlene García-Macedo; Gómez-Oliván, Leobardo M.; Ángel H. Sandoval-Trujillo; Keila Isaac-Olive; Ninfa Ramírez-Durán

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are compounds that can be quantified by fluorescence due to their high quantum yield. Haloalkalitolerant bacteria tolerate wide concentration ranges of NaCl and pH. They are potentially useful in the PAHs bioremediation of saline environments. However, it is known that salinity of the sample affects fluorescence signal regardless of the method. The objective of this work was to carry out a comparative study based on the sensitivity, linearity, and detec...

  2. Cysteamine capped CdS quantum dots as a fluorescence sensor for the determination of copper ion exploiting fluorescence enhancement and long-wave spectral shifts

    Science.gov (United States)

    Boonmee, Chanida; Noipa, Tuanjai; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2016-12-01

    We described a turn-on fluorescence sensor for the determination of Cu2 + ions, utilizing the quantum confinement effect of cadmium sulfide quantum dots capped with cysteamine (Cys-CdS QDs). The fluorescence intensity of the Cys-CdS QDs was both enhanced and red shifted (from blue-green to yellow) in the presence of Cu2 +. Fluorescence enhancement was linearly proportional to the concentration of Cu2 + in the concentration range 2 to 10 μM. Other cations at the same concentration level did not significantly change the intensity and spectral maxima of Cys-CdS QDs, except Ag+. The limit of detection was 1.5 μM. The sensor was applied to the determination of Cu2 + in (spiked) real water samples and gave satisfactory results, with recoveries ranging from 96.7 to 108.2%, and with RSDs ranging from 0.3 to 2.6%.

  3. Sequential determination of lead and cobalt in tap water and foods samples by fluorescence.

    Science.gov (United States)

    Talio, María Carolina; Alesso, Magdalena; Acosta, María Gimena; Acosta, Mariano; Fernández, Liliana P

    2014-09-01

    In this work, a new procedure was developed for the separation and preconcentration of lead(II) and cobalt(II) in several water and foods samples. Complexes of metal ions with 8-hydroxyquinolein (8-HQ) were formed in aqueous solution. The proposed methodology is based on the preconcentration/separation of Pb(II) by solid-phase extraction using paper filter, followed by spectrofluorimetric determination of both metals, on the solid support and the filtered aqueous solution, respectively. The solid surface fluorescence determination was carried out at λem=455 nm (λex=385 nm) for Pb(II)-8-HQ complex and the fluorescence of Co(II)-8-HQ was determined in aqueous solution using λem=355 nm (λex=225 nm). The calibration graphs are linear in the range 0.14-8.03×10(4) μg L(-1) and 7.3×10(-2)-4.12×10(3) μg L(-1), for Pb(II) and Co(II), respectively, with a detection limit of 4.3×10(-2) and 2.19×10(-2) μg L(-1) (S/N=3). The developed methodology showed good sensitivity and adequate selectivity and it was successfully applied to the determination of trace amounts of lead and cobalt in tap waters belonging of different regions of Argentina and foods samples (milk powder, express coffee, cocoa powder) with satisfactory results. The new methodology was validated by electrothermal atomic absorption spectroscopy with adequate agreement. The proposed methodology represents a novel application of fluorescence to Pb(II) and Co(II) quantification with sensitivity and accuracy similar to atomic spectroscopies.

  4. Flow injection fluorescence determination of dopamine using a photo induced electron transfer (PET) boronic acid derivative

    Energy Technology Data Exchange (ETDEWEB)

    Ebru Seckin, Z. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Volkan, Muervet [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey)]. E-mail: murvet@metu.edu.tr

    2005-08-15

    An automated flow injection analysis system was developed for the fluorometric determination of dopamine in pharmaceutical injections. The method is based on the quenching effect of dopamine on m-dansylaminophenyl boronic acid (DAPB) fluorescence due to the reverse photo induced electron transfer (PET) mechanism. Effects of pH and interfering species on the determination of dopamine were examined. Calibration for dopamine, based on quenching data, was linear in the concentration range of 1.0 x 10{sup -5} to 1.0 x 10{sup -4} M. Detection limit (3 s) of the method was found to be 3.7 x 10{sup -6} M. Relative standard deviation of 1.2% (n = 10) was obtained with 1.0 x 10{sup -5} M dopamine standard solution. The proposed method was applied successfully for the determination of dopamine in pharmaceutical injection sample. The sampling rate was determined as 24 samples per hour.

  5. Uranium industry annual 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    The Uranium Industry Annual 1996 (UIA 1996) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1996 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. Data on uranium raw materials activities for 1987 through 1996 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2006, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. A feature article, The Role of Thorium in Nuclear Energy, is included. 24 figs., 56 tabs.

  6. A set of enhanced green fluorescent protein concatemers for quantitative determination of nuclear localization signal strength.

    Science.gov (United States)

    Böhm, Jennifer; Thavaraja, Ramya; Giehler, Susanne; Nalaskowski, Marcus M

    2017-09-15

    Regulated transport of proteins between nucleus and cytoplasm is an important process in the eukaryotic cell. In most cases, active nucleo-cytoplasmic protein transport is mediated by nuclear localization signal (NLS) and/or nuclear export signal (NES) motifs. In this study, we developed a set of vectors expressing enhanced GFP (EGFP) concatemers ranging from 2 to 12 subunits (2xEGFP to 12xEGFP) for analysis of NLS strength. As shown by in gel GFP fluorescence analysis and αGFP Western blotting, EGFP concatemers are expressed as fluorescent full-length proteins in eukaryotic cells. As expected, nuclear localization of concatemeric EGFPs decreases with increasing molecular weight. By oligonucleotide ligation this set of EGFP concatemers can be easily fused to NLS motifs. After determination of intracellular localization of EGFP concatemers alone and fused to different NLS motifs we calculated the size of a hypothetic EGFP concatemer showing a defined distribution of EGFP fluorescence between nucleus and cytoplasm (n/c ratio = 2). Clear differences of the size of the hypothetic EGFP concatemer depending on the fused NLS motif were observed. Therefore, we propose to use the size of this hypothetic concatemer as quantitative indicator for comparing strength of different NLS motifs. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Dansylglycine, a fluorescent probe for specific determination of halogenating activity of myeloperoxidase and eosinophil peroxidase.

    Science.gov (United States)

    Bertozo, Luiza de Carvalho; Zeraik, Maria Luiza; Ximenes, Valdecir Farias

    2017-09-01

    Myeloperoxidase (MPO) and eosinophil peroxidase (EPO) are enzymes present in neutrophil and eosinophil leukocytes, respectively. Here, we present the development of a sensitive and specific assay for determination of the halogenating enzymatic activity of MPO and EPO based on the electrophilic attack of HOCl and HOBr on aromatic ring of dansylglycine (DG). We found that the intrinsic fluorescence of DG was promptly depleted by the action of these acids. In the presence of the enzymes, the fluorescence bleaching was dependent of chloride (Cl(-)) and bromide (Br(-)), which makes the assay able to distinguish the halogenating from the peroxidase activity. A linear correlation was obtained between the hydrogen peroxide (H2O2) concentration and the fluorescent decay. Similarly, the enzyme activity was measured by keeping constant H2O2. The method was applied for studding MPO/EPO specific inhibitors as 5-fluortryptamine (reversible inhibitor) and 4-hydroxybenzhydrazide (irreversible inhibitor). Differently of the taurine chloramine/3,3',5,5'-tetramethylbenzidine assay, which is among the most used technique, the dansylglycine assay was able to differentiate these inhibitors based on their kinetic behavior. In conclusion, this assay can differentiate the peroxidase and halogenating activity of MPO and EPO. Moreover, the method is adequate for real-time measurement of the production of HOCl and HOBr. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Two-step laser excited atomic fluorescence spectrometry determination of mercury

    Science.gov (United States)

    Resto, W.; Badini, R. G.; Smith, B. W.; Stevenson, C. L.; Winefordner, J. D.

    1993-04-01

    A novel method for the determination of mercury by laser excited atomic fluorescence with electrothermal atomization (LEAFS-ETA) has been developed. The experimental set-up consisted of a dual dye-laser system pumped with a XeCl excimer laser operated at 10 Hz, and an electrothermal atomizer with platform atomization. The atomization program allowed time for the injection of Pd (as a matrix modifier) and used a drying step at 110°C and an atomization step at 1200°C. The collection is made at 90° using a pierced mirror, an achromat lens and a long-pass filter. The monochromator is fitted with a 1P28 PMT. The signal is processed by using a boxcar and an analog to digital interface. The excitation scheme is a two-step process, with λ 1 = 253.7 nm and λ 2 = 435.8 nm. Direct fluorescence is observed at 546.1 nm. The limit of detection (LOD) obtained is 90 fg (9 pptr with 10 μ1 injection). The linear dynamic range (LDR) is five orders of magnitude and is limited by the non-linearity of the co-operative processes occurring at higher concentrations. In order to extend the LDR to higher amounts of mercury, indirect fluorescence is collected with the less sensitive line at 407.8 nm, allowing concentrations of 1 ppm and up to be measured, extending the LDR of the technique to at least seven orders of magnitude.

  9. Total reflection x-ray fluorescence: Determination of an optimum geometry

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Y.M. [Pohang Univ. of Science and Technology (Korea, Republic of); Chang, C.H.; Padmore, H.A. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Total reflection X-Ray Fluorescence (TXRF) is a widely used technique in which the normal trace element detection capability of hard x-ray fluorescence (XRF) is enhanced by use of an x-ray reflective substrate. TXRF is more sensitive than normal photon induced XRF due to the reduction of the substrate scattering and fluorescence signals. This reduction comes about because in total external reflection, the photon field only penetrates about 20 {angstrom} into the surface, instead of typically 50 {mu}m for a silicon substrate at normal incidence for 10 KeV photons. The technique is used in many fields of trace element analysis, and is widely used in the determination of metal impurity concentrations on and in the surface of silicon wafers. The Semiconductor Industry Association roadmap (SIA) indicates a need for wafer contamination detection at the 10{sup 7}atoms/cm{sup 2} level in the next few years. Current commercial systems using rotating anode x-ray sources presently routinely operate with a sensitivity level of around 10{sup 10} atoms/cm{sup 2} and this has led to interest in the use of synchrotron radiation to extend the sensitivity by three orders of magnitude. The pioneering work of Pianetta and co-workers at SSRL has clearly shown that this should be possible, using a fully optimized source and detector. The purpose of this work is to determine whether ALS would be a suitable source for this type of highly sensitive wafer TXRF. At first look it appears improbable as the SSRL work used a high flux multipole wiggler source, and it is clear that the detected fluorescence for relevant concentrations is small. In addition, SSRL operates at 3.0 GeV rather than 1.9 GeV, and is therefore more naturally suited to hard x-ray experiments. The aim of this work was therefore to establish a theoretical model for the scattering and fluorescence processes, so that one could predict the differences between alternative geometries and select an optimum configuration.

  10. Determination of transfer factors of uranium, thorium, radium and lead from soil to agricultural product in Japan for estimating internal radiation dose through ingestion

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Tomozo [Radioactive Waste Management Funding and Research Center, Tokyo (Japan); Tashiro, Yoshikazu; Fujinaga, Hideshi [Sumitomo Metal Mining Co. Ltd., Tokai, Ibaraki (Japan); Ishii, Tomoaki; Gunji, Yasuyoshi [Nuclear Fuel Industries Ltd., Tokai, Ibaraki (Japan). Tokai Works

    2002-09-01

    The transfer factors (TFs) of uranium (U), thorium (Th), radium (Ra) and lead (Pb) from soil to agricultural products were determined in order to estimate the internal radiation dose to the human body through ingestion. Samples of rice, potato, onion, cabbage, mandarin orange, spinach, apple and soil were collected from various districts in Japan. After appropriate pretreatment of the samples, concentrations in the sample solutions were measured by Inductively coupled plasma-mass spectrometry (ICP-MS) (for U, Th and Pb) and liquid scintillation counter (for Ra). It was recognized that TFs were 4.9 x 10{sup -6} (apple) and 3.6 x 10{sup -4} (spinach) for U, 2.8 x 10{sup -6} (apple) and 2.3 x 10{sup -4} (spinach) for Th, and 4.0 x 10{sup -3} (hulled rice), 7.0 x 10{sup -5} (onion) and 5.0 x 10{sup -3} (hulled rice) for Pb. The TF of Ra, however, was not determined due to detection limitations. TF values obtained in the present study range from the same order of magnitude to 1/100 compared to the data in Technical Report Series No.364 (TRS364) as reported by IAEA. It was revealed that the internal radiation dose caused by the intake of uranium series radioactive nuclides through agricultural food ingestion was 16 {mu}Sv/y, where Pb was the most contributory nuclide. (author)

  11. Experiments and Simulations of the Use of Time-Correlated Thermal Neutron Counting to Determine the Multiplication of an Assembly of Highly Enriched Uranium

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; Mathew T. Kinlaw; Scott M. Watson; Jeffrey M. Kalter; Eric C. Miller; William A. Noonan

    2014-11-01

    A series of experiments and numerical simulations using thermal-neutron time-correlated measurements has been performed to determine the neutron multiplication, M, of assemblies of highly enriched uranium available at Idaho National Laboratory. The experiments used up to 14.4 kg of highly-enriched uranium, including bare assemblies and assemblies reflected with high-density polyethylene, carbon steel, and tungsten. A small 252Cf source was used to initiate fission chains within the assembly. Both the experiments and the simulations used 6-channel and 8-channel detector systems, each consisting of 3He proportional counters moderated with polyethylene; data was recorded in list mode for analysis. 'True' multiplication values for each assembly were empirically derived using basic neutron production and loss values determined through simulation. A total of one-hundred and sixteen separate measurements were performed using fifty-seven unique measurement scenarios, the multiplication varied from 1.75 to 10.90. This paper presents the results of these comparisons and discusses differences among the various cases.

  12. Experiments and Simulations of the Use of Time-Correlated Thermal Neutron Counting to Determine the Multiplication of an Assembly of Highly Enriched Uranium

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; Mathew T. Kinlaw; Scott M. Watson; Jeffrey M. Kalter; Eric C. Miller; William A. Noonan

    2014-11-01

    A series of experiments and numerical simulations using thermal-neutron time-correlated measurements has been performed to determine the neutron multiplication, M, of assemblies of highly enriched uranium available at Idaho National Laboratory. The experiments used up to 14.4 kg of highly-enriched uranium, including bare assemblies and assemblies reflected with high-density polyethylene, carbon steel, and tungsten. A small 252Cf source was used to initiate fission chains within the assembly. Both the experiments and the simulations used 6-channel and 8-channel detector systems, each consisting of 3He proportional counters moderated with polyethylene; data was recorded in list mode for analysis. 'True' multiplication values for each assembly were empirically derived using basic neutron production and loss values determined through simulation. A total of one-hundred and sixteen separate measurements were performed using fifty-seven unique measurement scenarios, the multiplication varied from 1.75 to 10.90. This paper presents the results of these comparisons and discusses differences among the various cases.

  13. Determination of metals in lubricating oils by X-ray fluorescence spectrometry.

    Science.gov (United States)

    Pouzar, M; Cernohorský, T; Krejcová, A

    2001-06-21

    The determination of common wear metals, namely iron, chromium, copper, zinc and lead, in a wide range of lubricating oil samples was investigated for the use of a low-cost, wavelength-dispersive X-ray fluorescence spectrometer. The procedure provided results in satisfactory agreement with inductively coupled plasma spectrometry used as reference method after microwave digestion of the samples in concentrated nitric acid. Statistical tests following extensive regression analyses of the data indicated that interelement effects were not statistically significant and that a simple linear regression was adequate for the calibration of individual metals.

  14. Use of X-ray Fluorescence Analysis for the Determination of Rare Earth Elements

    Science.gov (United States)

    Schramm, Rainer

    2016-09-01

    X-ray fluorescence spectrometry (XRF) is a powerful tool for the analysis of solid material. That is the reason why the technique was applied for the determination of rare earth elements (REEs) since about 1970. At present, energy-dispersive XRF and wavelength-dispersive XRF are used for the analysis of pressed powder pellets or fused Li-borate beads containing REEs. The production of reliable results can only be achieved by careful optimization of the parameter, in particular the selection of spectral lines. The quantification is based on a calibration realized by using reference samples.

  15. Rapid determination of succinylcholine in human plasma by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Lagerwerf, A J; Vanlinthout, L E; Vree, T B

    1991-10-04

    A high-performance liquid chromatographic method with fluorometric detection has been developed for the determination of succinylcholine in human plasma. Succinylcholine shows fluorescence at 282 nm with an excitation at 257 nm. The assay is sensitive, reproducible and linear for concentrations ranging from 100 ng/ml to 100 micrograms/ml of succinylcholine. In a pilot study the plasma concentration-time curve showed a triphasic elimination, with half-lives of 0.4, 1.2 and 8 min, respectively. In a clinical setting, drugs commonly administered during anaesthesia did not interfere with the assay. This method provides a simple and time-saving alternative to existing methods.

  16. X-ray fluorescence spectrometry determination of open-hearth furnace slag by pressed powder briquetting

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A rapid analysis method of determining content of eight compounds of open-hearth furnace slag was developed using X-ray fluorescence spectrometry and pressed powder briquettes. Matrix effect was corrected using theoretical alpha coefficient. Grains-size effect was eliminated by optimized sample preparation technique parameters. Mineral effect was corrected with standard curve of specially made standard samples. The analysis results of TiO2, TFe, SiO2, MgO, Al2O3,CaO, MnO and P2O5 in slag samples showed that both precision and accuracy are comparable with that of chemical method.

  17. Quantitative Determination of Spatial Protein-protein Proximity in Fluorescence Confocal Microscopy

    CERN Document Server

    Wu, Yong; Ou, Jimmy; Li, Min; Toro, Ligia; Stefani, Enrico

    2009-01-01

    To quantify spatial protein-protein proximity (colocalization) in fluorescence microscopic images, cross-correlation and autocorrelation functions were decomposed into fast and slowly decaying components. The fast component results from clusters of proteins specifically labeled and the slow one from background/image heterogeneity. We show that the calculation of the protein-protein proximity index and the correlation coefficient are more reliably determined by extracting the fast-decaying component. This new method is illustrated by analyzing colocalization in both simulated and biological images.

  18. Determination of minor and trace elements in kidney stones by x-ray fluorescence analysis

    Science.gov (United States)

    Srivastava, Anjali; Heisinger, Brianne J.; Sinha, Vaibhav; Lee, Hyong-Koo; Liu, Xin; Qu, Mingliang; Duan, Xinhui; Leng, Shuai; McCollough, Cynthia H.

    2014-03-01

    The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. In particular, x-ray fluorescence (XRF) can be very useful for the determination of minor and trace materials in the kidney stone. The X-ray fluorescence measurements were performed at the Radiation Measurements and Spectroscopy Laboratory (RMSL) of department of nuclear engineering of Missouri University of Science and Technology and different kidney stones were acquired from the Mayo Clinic, Rochester, Minnesota. Presently, experimental studies in conjunction with analytical techniques were used to determine the exact composition of the kidney stone. A new type of experimental set-up was developed and utilized for XRF analysis of the kidney stone. The correlation of applied radiation source intensity, emission of X-ray spectrum from involving elements and absorption coefficient characteristics were analyzed. To verify the experimental results with analytical calculation, several sets of kidney stones were analyzed using XRF technique. The elements which were identified from this techniques are Silver (Ag), Arsenic (As), Bromine (Br), Chromium (Cr), Copper (Cu), Gallium (Ga), Germanium (Ge), Molybdenum (Mo), Niobium (Nb), Rubidium (Rb), Selenium (Se), Strontium (Sr), Yttrium (Y), Zirconium (Zr). This paper presents a new approach for exact detection of accurate material composition of kidney stone materials using XRF instrumental activation analysis technique.

  19. Determination of phenylurea pesticides by direct laser photo-induced fluorescence.

    Science.gov (United States)

    Diaw, P A; Maroto, A; Mbaye, O M A; Gaye-Seye, M D; Stephan, L; Coly, A; Deschamps, L; Tine, A; Aaron, J J; Giamarchi, P

    2013-11-15

    A direct Laser Photo-Induced Fluorescence (DL-PIF) method is developed for the determination of two phenylurea pesticides, namely fenuron and diflubenzuron. The DL-PIF method uses a tunable Nd:YAG-OPO Laser to obtain the photoproduct(s) and to simultaneously analyse their fluorescence in a short acquisition time on an intensified CCD camera. Compared to classical PIF methods, the use of a tunable laser improves the selectivity (by choosing the suitable excitation wavelength), increases the sensitivity (due to the high energy of the beam) and also reduces the time of analysis. The analytical performances of this method for the determination of both pesticides are satisfactory in comparison to other classical PIF methods published for the determination of phenylurea pesticides. The calibration curves were linear over one order of magnitude and the limits of detection were in the ng mL(-1) range. Satisfactory recoveries were obtained in the analysis of both pesticides in river and sea water spiked samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Determination of cadmium in tobacco by solid surface fluorescence using nylon membranes coated with carbon nanotubes.

    Science.gov (United States)

    Carolina Talio, María; Alesso, Magdalena; Acosta, Mariano; Olsina, Roberto; Fernández, Liliana P

    2013-03-30

    A new methodology based on fluorescent signal enhancement of o-cresolphthalein (o-CPT) for traces of cadmium determination is proposed. The dye was retained on membrane filters in the presence of a micellar surfactant solution of carbon nanotubes (CNTs). All the experimental variables that influence both the preconcentration procedure and the fluorimetric sensitivity were carefully optimized. The calibration graph using zeroth order regression was linear from 6.5 ng L(-1) to 5.65×10(5) ng L(-1), with a correlation coefficient higher than 0.999. Under optimal conditions, the limits of detection and quantification were of 2 ng L(-1) and 6.5 ng L(-1). respectively. The proposed method showed good sensitivity and selectivity, with good tolerance to foreign ions, and it was applied to the determination of trace amounts of cadmium in leachate from cigarettes' tobacco samples with satisfactory results. The trueness of the recommended procedure was assessed through parallel analysis of the samples with electrothermal atomization atomic absorption spectrometry. This methodology represents an innovative and attractive application of membrane filters that enables metal traces determination by solid surface fluorescence.

  1. Determination of imidacloprid in water samples via photochemically induced fluorescence and second-order multivariate calibration.

    Science.gov (United States)

    Fuentes, Edwar; Cid, Camila; Báez, María E

    2015-03-01

    This paper presents a new method for the determination of imidacloprid in water samples; one of the most widely used neonicotinoid pesticides in the farming industry. The method is based on the measurement of excitation-emission spectra of photo-induced fluorescence (PIF-EEMs) associated with second-order multivariate calibration with a parallel factor analysis (PARAFAC) and unfolded partial least squares coupled to residual bilinearization (U-PLS/RBL). The second order advantage permitted the determination of imidacloprid in the presence of potential interferences, which also shows photo-induced fluorescence (other pesticides and/or unexpected compounds of the real samples). The photoreaction was performed in 100-μl disposable micropipettes. As a preliminary step, solid phase extraction on C18 (SPE-C18) was applied to concentrate the analyte and diminish the limit of detection. The LOD was approximately 1 ng mL(-1), which is suitable for detecting imidacloprid in water according to the guidelines established in North America and Europe. The PIF-EEMs coupled to PARAFAC or U-PLS/RBL was successfully applied for the determination of imidacloprid in different real water samples, with an average recovery of 101±10%.

  2. Response surface optimization of microwave-assisted extraction for HPLC-fluorescence determination of puerarin and daidz

    Institute of Scientific and Technical Information of China (English)

    Ying-Kun Liu; E Yan; Han-Ying Zhan; Zhi-Qi Zhang

    2011-01-01

    Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved by soaking the sample with 70% methanol

  3. Quantitative determination of paralytic shellfish poisoning toxins in shellfish using prechromatography oxidation and liquid chromatography with fluorescence detection: interlaboratory study

    NARCIS (Netherlands)

    Lawrence, J.F.; Niedzwiadek, B.; Menard, C.; Wezenbeek, P.

    2004-01-01

    An interlaboratory study was conducted for the determination of paralytic shellfish poisoning (PSP) toxins in shellfish. The method used liquid chromatography with fluorescence detection after prechromatographic oxidation of the toxins with hydrogen peroxide and periodate. The PSP toxins studied

  4. [Fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid].

    Science.gov (United States)

    Wu, F; Fu, M; Wei, X; Yang, W; Hu, R; Guo, L

    2001-06-01

    A fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid with trytophan in the medium pH 11.01 NH3-NH4Cl is studied. The calibration curve is linear for p-hydroxyphenylpyruvic acid from 0 to 15 micrograms.mL-1 with lambda ex/lambda em = 285/356 nm. The detection limit is 0.37 microgram.mL-1. Twenty replicate determinations of solutions containing 10 micrograms.mL-1 p-hydroxyphenylpyruvic acid show a relative standard deviation of 1.2%. This method can be applied to the determination of p-hydroxyphenylpyruvic acid in serum with satisfactory results.

  5. Determination of metoprolol in rabbit blood using capillary electrophoresis with laser-induced fluorescence detection

    Institute of Scientific and Technical Information of China (English)

    Yu Yun Chen; Wei Ping Yang; Zhu Jun Zhang

    2011-01-01

    This work described a sensitive method for determination of metoprolol in rabbit plasma. The method involved purification by ultrafiltration, derivatization with fluorescein isothiocyanate, determination by capillary electrophoresis (CE) coupled with laser-induced fluorescence (LIF) detector. Other components in plasma including a variety of amino acids and proteins did not interfere with the determination of metoprolol in experimental condition. The assay had a wide range (2.0-500 ng/mL) of linearity and a detection limit of 0.8 ng/mL. The intra-and inter-day precisions were satisfactory with relative standard deviation (RSD) less than 10.0% and accuracy within 10.0%. This method was successfully applied to pharmacokinetic study of metoprolol in rabbit blood. (c) 2010 Yu Yun Chen. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  6. Microwave assisted one-step green synthesis of fluorescent carbon nanoparticles from ionic liquids and their application as novel fluorescence probe for quercetin determination

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Deli; Yuan, Danhua [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); He, Hua, E-mail: dochehua@163.com [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China); Gao, Mengmeng [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China)

    2013-08-15

    In this study, a new sensitive and convenient method for the determination of quercetin based on the fluorescence quenching of fluorescent carbon nanoparticles (CNPs) was developed. The CNPs derived from ionic liquids were prepared using a green and rapid microwave-assisted synthetic approach for the first time. The one-step green preparation process is simple and effective, neither a strong acid solvent nor surface modification reagent is needed, which makes this approach very suitable for large-scale production. The prepared CNPs were characterized by high-resolution transmission electron microscopy, Fourier transform infrared spectrometry, elemental analysis and spectrofluorometry. In NH{sub 3}–NH{sub 4}Cl buffer solution (pH 9.47), the fluorescence signals of CNPs decreased obviously with increase of the quercetin concentration. The effect of other coexisting foreign substances on the intensity of CNPs showed a low interference response. Under the optimum conditions, the fluorescence intensity presented a linear response versus quercetin concentration according to the Stern–Volmer equation with an excellent 0.9989 correlation coefficient. The linearity ranged from 2.87×10{sup −6} to 31.57×10{sup −6} mol L{sup −1} with the detection limit (3σ) of 9.88×10{sup −8} mol L{sup −1}. The recovery of this method was in the range of 93.3–105.1%. Therefore, the CNPs could to be a promising candidate as a fluorescence probe for the detection of trace levels of quercetin due to their advantages in low-cost production, low cytotoxicity, strong fluorescence and excellent biocompatibility. -- Highlights: ► Fluorescent CNPs were synthesized with microwave pyrolysis approach. ► Ionic liquids were used as sources of carbon and nitrogen for the first time. ► The formation and functionalization of CNPs were accomplished simultaneously. ► CNPs were used as fluorescent probes for the determination of quercetin. ► A sensitive and convenient method based

  7. Determining the isotopic compositions of uranium and fission products in radioactive environmental microsamples using laser ablation ICP-MS with multiple ion counters

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, Sergei F.; Prohaska, Thomas [University of Natural Resources and Applied Life Sciences, Department of Chemistry, Division of Analytical Chemistry-VIRIS Laboratory, Vienna (Austria)

    2008-01-15

    This paper presents the application of a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) - a Nu Plasma HR - equipped with three ion-counting multipliers and coupled to a laser ablation system (LA) for the rapid and sensitive determination of the {sup 235}U/{sup 238}U, {sup 236}U/{sup 238}U, {sup 145}Nd/{sup 143}Nd, {sup 146}Nd/{sup 143}Nd, {sup 101}Ru/({sup 99}Ru+{sup 99}Tc) and {sup 102}Ru/({sup 99}Ru+{sup 99}Tc) isotope ratios in microsamples collected in the vicinity of Chernobyl. Microsamples with dimensions ranging from a hundred {mu}m to about 1 mm and with surface alpha activities of 3-38 mBq were first identified using nuclear track radiography. U, Nd and Ru isotope systems were then measured sequentially for the same microsample by LA-MC-ICP-MS. The application of a zoom ion optic for aligning the ion beams into the ion counters allows fast switching between different isotope systems, which enables all of the abovementioned isotope ratios to be measured for the same microsample within a total analysis time of 15-20 min (excluding MC-ICP-MS optimization and calibration). The {sup 101}Ru/({sup 99}Ru+{sup 99}Tc) and {sup 102}Ru/({sup 99}Ru+{sup 99}Tc) isotope ratios were measured for four microsamples and were found to be significantly lower than the natural ratios, indicating that the microsamples were contaminated with the corresponding fission products (Ru and Tc). A slight depletion in {sup 146}Nd of about 3-5% was observed in the contaminated samples, but the Nd isotopic ratios measured in the contaminated samples coincided with natural isotopic composition within the measurement uncertainty, as most of the Nd in the analyzed samples originates from the natural soil load of this element. The {sup 235}U/{sup 238}U and {sup 236}U/{sup 238}U isotope ratios were the most sensitive indicators of irradiated uranium. The present work yielded a significant variation in uranium isotope ratios in microsamples, in contrast with previously

  8. Simultaneous determination of sulpiride and its alkaline degradation product by second derivative synchronous fluorescence spectroscopy.

    Science.gov (United States)

    Abdelal, Amina; El-Enany, Nahed; Belal, Fathalla

    2009-12-15

    Simple and sensitive synchronous fluorimetric, and second derivative synchronous fluorometric methods were developed for the validated and simultaneous determination of sulpiride (SLP) and its alkaline degradation product (DSLP). The method is based on measuring the synchronous fluorescence of both the drug and its degradation product in borate buffer of pH 8 at Deltalambda of 45 nm. The peak amplitude ((2)D) was measured at 295.5 and 342 nm for SLP and DSLP, respectively. The different experimental parameters affecting the synchronous fluorescence intensity of both compounds were studied and optimized. The fluorescence-concentration plots were rectilinear over the range of 0.05-1.0 and 2-10 microg mL(-1) for SLP and DSLP, respectively. The limits of detection (LOD) were 0.02 and 0.4 microg mL(-1) and quantification limits (LOQs) were 0.05 and 1.2 microg mL(-1) for SLP and DSLP, respectively. The proposed methods were successfully applied to commercial capsules and tablets. Statistical comparison of the results with those of the official method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods, respectively. The method was utilized to study the kinetics of the alkaline induced degradation of the drug. The application was further extended to include the in vivo and in vitro determination of sulpiride. The mean % recoveries (n=3) were 100.22+/-2.04 and 92.00+/-3.00 for spiked and real human plasma, respectively.

  9. Uranium industry in Canada

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    Current state of uranium industry in Canada has been considered. It is shown that in Canada, which is the major supplier of uranium, new methods of prospecting, mining and processing of uranium are developed and the old ones are improved. Owing to automation and mechanization a higher labour productivity in uranium ore mining is achieved. The uranium industry of Canada can satisfy the future demands in uranium but introduction of any new improvement will depend completely on the rate of nuclear power development.

  10. Reusable fluorescent photocrosslinked polymeric sensor for determining lead ions in aqueous media

    Science.gov (United States)

    Çubuk, Soner; Taşci, Neşe; Kahraman, Memet Vezir; Bayramoğlu, Gülay; Yetimoğlu, Ece Kök

    2016-04-01

    In this study, 1-vinylimidazole units bearing photocured films were prepared as fluorescent sensors towards Pb2 + in aqueous solutions. The influence of experimental parameters such as pH, time and foreign ion concentrations were investigated. Sensor response was linear over a concentration range of 4.83 × 10- 8 to 4.83 × 10- 7 mol L- 1. The sensor was highly sensitive with a detection limit as low as 1.87 × 10- 8 mol L- 1, and having a selectivity of over four thousand fold. The response time of the sensor was found to be 5 min. When stored in a desiccator at room temperature the sensor showed good stability after a 5 month period. The fluorescence sensors were successful in the determination of Pb2 + in water samples as well as in the determination of the quantitative amount of lead and the results were satisfying. Compared with previously reported literature, the prepared new sensor is highly sensitive and selective.

  11. Determining Optimal Fluorescent Agent Concentrations in Dental Adhesive Resins for Imaging the Tooth/Restoration Interface.

    Science.gov (United States)

    Bim Júnior, Odair; Cebim, Marco A; Atta, Maria T; Machado, Camila M; Francisconi-Dos-Rios, Luciana F; Wang, Linda

    2017-02-01

    Fluorescent dyes like Rhodamine B (RB) have been used to identify the spatial distribution of adhesive restorative materials in the tooth/restoration interface. Potential effects of the addition of RB to dental adhesives were addressed in the past, but no further information is available on how to determine suitable concentrations of RB in these bonding agents for imaging in the confocal laser scanning microscope. This study provides systematical strategies for adding RB to viscous dental adhesive resins, focusing on the determination of the lowest range of dye concentrations necessary to achieve an acceptable image of the dentin/adhesive interface. It was demonstrated that optimized images of the resin distribution in dentin can be produced with 0.1-0.02 mg/mL of RB in the (tested) adhesives. Our approaches took into account aspects related to the dye concentration, photophysical parameters in different host media, specimen composition and morphology to develop a rational use of the fluorescent agent with the resin-based materials. Information gained from this work can help optimize labeling methods using dispersions of low-molecular-weight dyes in different monomer blend systems.

  12. Highly sensitive fluorescence optode based on polymer inclusion membranes for determination of Al(III) ions.

    Science.gov (United States)

    Suah, F B M; Ahmad, M; Heng, L Y

    2014-07-01

    This paper reports the use of a polymer inclusion membranes (PIMs) for direct determination of Al(III) ions in natural water by using a fluorescence based optode. The best composition of the PIMs consisted of 60 wt.% (m/m) poly (vinyl chloride) (PVC) as the base polymer, 20 wt.% (m/m) triton X-100 as an extractant, 20 wt.% (m/m) dioctyl phthalate (DOP) as plasticizer and morin as the reagent, was used in this study. The inclusion of triton X-100 was used for enhancing the sorption of Al(III) ions from liquid phase into the membrane phase, thus increasing the optode fluorescence intensity. The optimized optode was characterized by a linear calibration curve in the range from 7.41 × 10(-7) to 1.00 × 10(-4) molL(-1) of Al(III), with a detection limit of 5.19 × 10(-7) molL(-1). The response of the optode was 4 min and reproducible results were obtained for eight different membranes demonstrated good membrane stability. The optode was applied to the determination of Al(III) in natural water samples. The result obtained is comparable to atomic absorption spectrometry method.

  13. Uranium Metal Analysis via Selective Dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Chenault, Jeffrey W.

    2008-09-10

    Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this work was to establish a rapid routine analytical method to determine uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of up to 1000-fold higher total uranium concentrations (i.e., up to 30 wt% and more uranium) for samples to be taken during the upcoming sludge characterization campaign and in future analyses for sludge handling and processing. This report describes the experiments and results obtained in developing the selective dissolution technique to determine uranium metal concentration in K Basin sludge.

  14. Standard test method for determination of uranium or plutonium isotopic composition or concentration by the total evaporation method using a thermal ionization mass spectrometer

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This method describes the determination of the isotopic composition and/or the concentration of uranium and plutonium as nitrate solutions by the thermal ionization mass spectrometric (TIMS) total evaporation method. Purified uranium or plutonium nitrate solutions are loaded onto a degassed metal filament and placed in the mass spectrometer. Under computer control, ion currents are generated by heating of the filament(s). The ion beams are continually measured until the sample is exhausted. The measured ion currents are integrated over the course of the run, and normalized to a reference isotope ion current to yield isotopic ratios. 1.2 In principle, the total evaporation method should yield isotopic ratios that do not require mass bias correction. In practice, some samples may require this bias correction. When compared to the conventional TIMS method, the total evaporation method is approximately two times faster, improves precision from two to four fold, and utilizes smaller sample sizes. 1.3 The tot...

  15. Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Khuder, A. [Department of Chemistry, Atomic Energy Commission, P.O. Box 6091, Damascus (Syrian Arab Republic)], E-mail: scientific2@aec.org.sy; Sawan, M.Kh.; Karjou, J. [Department of Chemistry, Atomic Energy Commission, P.O. Box 6091, Damascus (Syrian Arab Republic); Razouk, A.K. [Department of Agriculture, Atomic Energy Commission, P.O. Box 6091, Damascus (Syrian Arab Republic)

    2009-07-15

    X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise (Anisum vulgare), licorice root (Glycyrrhiza glabra), and white wormwood (Artemisia herba-alba)

  16. Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Khuder, A.; Sawan, M. Kh.; Karjou, J.; Razouk, A. K.

    2009-07-01

    X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise ( Anisum vulgare), licorice root ( Glycyrrhiza glabra), and white wormwood ( Artemisia herba-alba).

  17. Uranium Glass: A Glowing Alternative to Conventional Sources of Radioactivity

    Science.gov (United States)

    Boot, Roeland

    2017-02-01

    There is a relatively simple way of using radioactive material in classroom experiments: uranium glass, which provides teachers with a suitable substance. By using the right computer software and a radiation sensor, it can be demonstrated that uranium glass emits radiation at a greater rate than the background radiation and with the aid of UV light a bright green luster appears. Therefore, with two pieces of uranium glass, students can learn about two different physical phenomena: fluorescence and radioactivity.

  18. Indirect determination of the electric field in plasma discharges using laser-induced fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vaudolon, J., E-mail: julien.vaudolon@cnrs-orleans.fr; Mazouffre, S., E-mail: stephane.mazouffre@cnrs-orleans.fr [CNRS - ICARE (Institut de Combustion Aérothermique Réactivité et Environnement), 1 C Av. de la Recherche Scientifique, 45071 Orléans Cedex 2 (France)

    2014-09-15

    The evaluation of electric fields is of prime interest for the description of plasma characteristics. In this work, different methods for determining the electric field profile in low-pressure discharges using one- and two-dimensional Laser-Induced Fluorescence (LIF) measurements are presented and discussed. The energy conservation, fluid, and kinetic approaches appear to be well-suited for the electric field evaluation in this region of the plasma flow. However, the numerical complexity of a two-dimensional kinetic model is penalizing due to the limited signal-to-noise ratio that can be achieved, making the computation of the electric field subject to large error bars. The ionization contribution which appears in the fluid model makes it unattractive on an experimental viewpoint. The energy conservation and 1D1V kinetic approaches should therefore be preferred for the determination of the electric field when LIF data are used.

  19. Study on Micro-extraction Column of Uranium

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Some samples of uranium are very complicated therefore they can not be determined directly by analysis instrument, so pretreatment is necessary. The micro-extraction column of uranium is a kind of

  20. Determination of optimal excitation and emission wavebands for detection of defect cherry tomato by using fluorescence emission and excitation matrix

    Science.gov (United States)

    Baek, In-Suck; Cho, Byoung-Kwan; Kim, Moon S.; Kim, Young-Sik

    2013-05-01

    Fluorescence imaging technique has been widely used for quality and safety measurements of agro-food materials. Fluorescence emission intensities of target materials are influenced by wavelengths of excitation sources. Hence, selection of a proper excitation wavelength is an important factor in differentiating target materials effectively. In this study, optimal fluorescence excitation wavelength was determined on the basis of fluorescence emission intensity of defect and sound areas of cherry tomatoes. The result showed that fluorescence responses of defect and sound surfaces of cherry tomatoes were most significantly separated with the excitation light wavelength range between 400 and 410 nm. Fluorescence images of defect cherry tomatoes were acquired with the LEDs with the central wavelength of 410 nm as the excitation source to verify the detection efficiency of cherry tomato defects. The resultant fluorescence images showed that the defects were discriminated from sound areas on cherry tomatoes with above 98% accuracy. This study shows that high power LEDs as the excitation source for fluorescence imaging are suitable for defect detection of cherry tomatoes.

  1. Uranium Industry Annual, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-28

    The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ``Decommissioning of US Conventional Uranium Production Centers,`` is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2.

  2. Determination of Adsorption Capacity and Kinetics of Amidoxime-Based Uranium Adsorbent Braided Material in Unfiltered Seawater Using a Flume Exposure System

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Park, Jiyeon [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Bonheyo, George T. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Jeters, Robert T. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Schlafer, Nicholas J. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.

    2015-08-31

    PNNL has developed a recirculating flume system for exposing braided adsorbent material to natural seawater under realistic temperature and flow-rate exposure conditions. The flumes are constructed of transparent acrylic material; they allow external light to pass into the flumes and permit photosynthetic growth of naturally present marine organisms (biofouling). Because the system consists of two flumes, replicate experiments can be conducted in which one of the flumes can be manipulated relative to the other. For example, one flume can be darkened to eliminate light exposure by placing a black tarp over the flume such that dark/light experiments can be conducted. Alternatively, two different braided adsorbents can be exposed simultaneously with no potential cross contamination issues. This report describes the first use of the PNNL flume system to study the impact of biofouling on adsorbent capacity. Experiments were conducted with the ORNL AI8 braided adsorbent material in light-exposed and darkened flumes for a 42-day exposure experiment. The major objective of this effort is to develop a system for the exposure of braided adsorbent material to unfiltered seawater, and to demonstrate the system by evaluating the performance of adsorption material when it is exposed to natural marine biofouling as it would be when the technology is used in the marine environment. Exposures of amidoxime-based polymeric braid adsorbents prepared by Oak Ridge Natural Laboratory (ORNL) were exposed to ambient seawater at 20°C in a flume system. Adsorption kinetics and adsorption capacity were assessed using time series determinations of uranium adsorption and one-site ligand saturation modeling. Biofouling in sunlight surface seawater has the potential to significantly add substantial biogenic mass to adsorption material when it is exposed for periods greater than 21 days. The observed biomass increase in the light flume was approximately 80% of the adsorbent mass after 42 days

  3. Maghemite nanoparticles bearing di(amidoxime groups for the extraction of uranium from wastewaters

    Directory of Open Access Journals (Sweden)

    Eva Mazarío

    2017-05-01

    Full Text Available Polyamidoximes (pAMD are known to have strong affinities for uranyl cations. Grafting pAMD onto the surface of functionalized maghemite nanoparticles (MNP leads to a nanomaterial with high capacities in the extraction of uranium from wastewaters by magnetic sedimentation. A diamidoxime (dAMD specifically synthesized for this purpose showed a strong affinity for uranyl: Ka = 105 M-1 as determined by Isothermal Titration Calorimetry (nano-ITC. The dAMD was grafted onto the surface of MNP and the obtained sorbent (MNP-dAMD was characterized. The nanohybrids were afterward incubated with different concentrations of uranyl and the solid phase recovered by magnetic separation. This latter was characterized by zeta-potential measurements, X-Ray Photoelectron Spectroscopy (XPS and X-Ray Fluorescence spectroscopy (XRF, whereas the supernatant was analyzed by Inductively Coupled Plasma coupled to Mass Spectrometry (ICP-MS. All the data fitted the models of Langmuir, Freundlich and Temkin isotherms very well. These isotherms allowed us to evaluate the efficiency of the adsorption of uranium by MNP-dAMD. The saturation sorption capacity (qmax was determined. It indicates that MNP-dAMD is able to extract up to 120 mg of uranium per gram of sorbent. Spherical aberration (Cs-corrected High-Resolution Scanning Transmission Electron Microscopy (HRSTEM confirmed these results and clearly showed that uranium is confined at the surface of the sorbent. Thus, MNP-dAMD presents a strong potential for the extraction of uranium from wastewaters.

  4. Determination of phycobiliproteins by capillary electrophoresis with laser-induced fluorescence detection.

    Science.gov (United States)

    Viskari, P J; Kinkade, C S; Colyer, C L

    2001-07-01

    Phycobiliproteins are derived from the photosynthetic apparatus of cyanobacteria and eukaryotic algae. They are composed of a protein backbone to which linear tetrapyrrole chromophores are covalently bound. Furthermore, they are water-soluble highly fluorescent, and relatively stable at room temperature and neutral pH. For this reason, capillary electrophoresis-laser induced fluorescence (CE-LIF) seems the idea method for determination of these important proteins. The effects of buffer additives such as sodium dodecyl sulfate (SDS)and putrescine on the separation of the three major phycobiliprotein types, namely allophycocyanin, phycocyanin, and phycoerythrin, with excitation and emission maxima at 652/660, 615/647, and 565(494)/575 nm, respectively, are considered. Detection limits for these proteins by CE-LIF are some 60-500 times better than by absorbance detection. The development of a fast and sensitive CE-LIF assay such as this is of potential significance to our understand ing of chemical and biological oceanographic processes.

  5. Optimization of fluorescence detection for polyaromatic hydrocarbon determination by using high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, P.J.; Carpenter, P.D.; Brady, P.H.; McCormick, M.J.; Griffiths, A.J.; Hatvani, T.S.G.; Rasdell, S.G. (Royal Melbourne Inst. of Tech., Victoria (Australia))

    1993-01-01

    Polyaromatic hydrocarbon determination is often one of the requirements in site evaluations and chemical audit studies, particularly where the site usage is to change from industrial to recreational or domestic housing. It is also a general parameter included in air particulate studies and water quality evaluations in the urban environment, where PAHs accumulate as a result of vehicle and industrial emissions. The procedures needed for the optimization of programmable fluorescence detectors have been investigated. The authors found that wavelength programs had to be developed from data obtained from the particular detector for which the program was to be used--programs reported in the literature or developed from data obtained on other instruments gave substantially lower sensitivities. The wavelength program they developed was a compromise between: chromatographic separation, abundance and relative sensitivity of each PAH; the ease with which a timed event could be included in the elution profile and; the relative importance of each PAH to the analyst. The success of programmable fluorescence detection was dependant on the reproducibility with which the detector was able to reset specified wavelengths, with corresponding detector response variability of up to 20% for one new detector.

  6. Determination of aristolochic acids by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Wang, Yinan; Chan, Wan

    2014-06-25

    Nephrotoxic and carcinogenic aristolochic acids (AAs) are naturally occurring nitrophenanthrene carboxylic acids in the herbal genus Aristolochia. The misuse of AA-containing herbs in preparing slimming drugs has caused hundred of cases of kidney disease in Belgium women in a slimming regime in the early 1990s. Accumulating evidence also suggested that prolong dietary intake of AA-contaminated food is one of the major causes to the Balkan endemic nephropathy that was first observed in the late 1950s. Therefore, analytical methods of high sensitivity are extremely important for safeguarding human exposure to AA-containing herbal medicines, herbal remedies, and food composites. In this paper, we describe the development of a new high-performance liquid chromatography coupled fluorescence detector (HPLC-FLD) method for the sensitive determination of AAs. The method makes use of a novel cysteine-induced denitration reaction that "turns on" the fluorescence of AAs for fluorometric detections. Our results showed that the combination of cysteine-induced denitration and HPLC-FLD analysis allows for sensitive quantification of AA-I and AA-II at detection limits of 27.1 and 25.4 ng/g, respectively. The method was validated and has been successfully applied in quantifying AAs in Chinese herbal medicines.

  7. Determination of Angiotensin-(1-7) with HPLC/Fluorescence-Detection.

    Science.gov (United States)

    Russ, Miriam; Hauser, Susanne; Wintersteiger, Reinhold; Greilberger, Joachim; Andrä, Michaela; Ortner, Astrid

    2016-01-01

    Angiotensin-(1-7) is an important active component in the renin-angiotensin-system. Due to its cardio protective effects it is now under investigation in combination with antioxidants as a reperfusion solution. The combination showed impressive effects on isolated hearts of male Wistar rats after induced ischemia. In this work a high performance liquid chromatography method with fluorescence detection was developed for the first time for in-process measurements as well as for stability tests of the peptide in the novel antioxidant-containing Karal® solution. For fluorescence detection of angiotensin-(1-7) fluorescamine as derivatization dye was applied. Under optimized conditions the method showed linearity over the range of 50 to 5000 ng/mL with R(2) of 0.9988 and an overall precision better than 5.0 %. LOD and LOQ were determined to be in the femtomol range on column. It was found that stability of angiotensin-(1-7) could be significantly improved in the antioxidant containing preparation compared to aqueous solutions.

  8. Surface area and volume determination of subgingival calculus using laser fluorescence.

    Science.gov (United States)

    Shakibaie, Fardad; Walsh, Laurence J

    2014-03-01

    Visible red (655 nm) laser fluorescence (LF) devices are currently used for identifying deposits of subgingival calculus on the root surfaces of teeth during dental examination and treatment; however, it is not known how the fluorescence readings produced by commercially available LF systems correlate to the nature of the deposits. This laboratory study explored the correlation between LF digital readings and the surface area and volume of subgingival calculus deposits on teeth. A collection of 30 extracted human posterior teeth with various levels of subgingival deposits of calculus across 240 sites were used in a clinical simulation, with silicone impression material used to replicate periodontal soft tissues. The teeth were scored by two examiners by using three commercial LF systems (DIAGNOdent, DIAGNOdent Pen and KEY3). The silicone was removed, and the teeth were removed for photography at × 20 magnification under white or ultraviolet light. The surface area, thickness, and volume were calculated, and both linear least squares regression and nonlinear (Spearman's rank method) correlation coefficients were determined. Visible red LF digital readings showed better correlation to calculus volume than to surface area. Overall, the best performance was found for the KEY3 system (Spearman coefficient 0.59), compared to the Classic DIAGNOdent (0.56) and the DIAGNOdent Pen (0.49). These results indicate that while visible red LF systems vary somewhat in performance, their LF readings provide a useful estimation of the volume of subgingival calculus deposits present on teeth.

  9. Spectrofluorimetric determination of 5-fluorouracil by fluorescence quenching of 9-anthracenecarboxylic acid

    Science.gov (United States)

    Khot, M. S.; Bhattar, S. L.; Kolekar, G. B.; Patil, S. R.

    2010-09-01

    Photo-induced intermolecular electron transfer (PET) interaction between excited singlet (S 1) state of 9-anthracene carboxylic acid (9-ANCA) and DNA bases of pyrimidines as uracil and 5-fluorouracil (5-FU) has been studied in water and ethanol solutions using steady-state fluorescence spectroscopy. The intensity of all emission bands of 9-ANCA was quenched in presence of uracil and 5-FU by electron transfer reaction without formation of an exciplex. It was found that uracil and 5-fluorouracil acts as effective electron donors and simultaneously quench the fluorescence of electron-accepting sensitizer 9-ANCA. The quenching by diffusion-controlled rate coincides well with the dynamic Stern-Volmer correlation. The bimolecular quenching rate constant (kqss) and electron transfer rate constant ( ket) observed are seen to be much higher for 5-fluorouracil than those for uracil. The thermodynamic parameters estimated by using the Rehm-Weller equation were used to propose a suitable mechanism for PET occurring between uracils and 9-ANCA. The proposed method was used to determine 5-fluorouracil from pharmaceutical samples with satisfactory results. The technique is more selective, sensitive and relatively free from coexisting substances.

  10. Determination of RNA degradation by capillary electrophoresis with cyan light-emitted diode-induced fluorescence.

    Science.gov (United States)

    Yang, Tzu-Hsueh; Chang, Po-Ling

    2012-05-25

    RNA integrity plays an important role in RNA studies because poor RNA quality may have a great impact on downstream methodologies. This study proposes a cost-effective, rapid, and sensitive method for determining RNA integrity based on capillary electrophoresis that utilizes a cyan light-emitted diode-induced fluorescence as a separation tool. The capillary was initially coated with 0.1% Poly(vinylpyrrolidone) (M(ave) 1,300,000 Da) to reduce electroosmotic flow and avoid RNA adsorption. When the capillary was filled with 0.4% poly(ethylene) oxide (M(ave) 4,000,000) and a nucleic acid-specific fluorescent dye, SYTO 9, the baseline separation of the 18S and 28S ribosomal RNAs (rRNAs) in total RNA was accomplished within 15 min. The lowest detectable concentration for the 18S and 28S rRNAs was estimated to be 50 pg/μL. Some peaks longer than the 28S rRNA that migrated slowly were observed as long as the initial total RNA concentration was optimized. The temperature-induced degradation of the large RNA fragments (longer than the 28S rRNA) was faster than that of 18S rRNA and 28S rRNA. These large RNA fragments may serve as a promising marker for testing RNA integrity compared to the traditional method. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Development of X-ray Fluorescence Spectrometer for Determination of Tc

    Institute of Scientific and Technical Information of China (English)

    SONG; You; ZHENG; Wei-ming; LIU; Gui-jiao; CHANG; Zhi-yuan

    2012-01-01

    <正>With the deepening of the spent nuclear fuel burnup in power reactor, one of the important fission products, technetium content also increases significantly in the spent fuel. Due to its complex behavior during uranium and plutonium separation, technetium distribution must be monitored in process of spent fuel reprocessing.

  12. Long-wavelength fluorescence polarization immunoassay: determination of amikacin on solid surface and gliadins in solution.

    Science.gov (United States)

    Sánchez-Martínez, María Lourdes; Aguilar-Caballos, María Paz; Gómez-Hens, Agustina

    2007-10-01

    The versatility of the fluorescence polarization immunoassay (FPIA) is increased by using two long-wavelength labels, Nile Blue and a ruthenium(II) chelate. The first label has been used to study the potential of FPIA on a solid surface using dry reagent technology. The aminoglycoside antibiotic amikacin has been used as an analyte model, and the method has been applied to the analysis of serum samples. The second label has been used to show the practical application of FPIA to the determination of macromolecules, using gliadins as an analyte model, which have been determined in gluten-free food. Very low amounts of anti-amikacin antibodies and amikacin-Nile Blue tracer were immobilized onto nitrocellulose membranes, for the development of the amikacin method, and the consumption of reagents is lower than in conventional FPIA. Only the addition of the standard or sample extract at an adequate pH is required at the analysis time. The analyte displaces the tracer from the tracer-antibody immunocomplex, obtaining a decrease in the fluorescence polarization proportional to the analyte concentration. The gliadin-Ru(II) chelate tracer shows a relatively long lifetime, which allows the observation of differences in fluorescence polarization values between the tracer-antibody complex and the tracer alone. The dynamic range of the calibration graphs for both analytes is 0.5-10 microg mL-1 and the detection limits are 0.1 and 0.09 microg mL-1 for amikacin and gliadins, respectively. The study of the precision gave values of relative standard deviations lower than 5 and 1.5% for the amikacin and gliadin methods, respectively. Amikacin was determined in human serum samples using a previous deproteinization step with acetonitrile, obtaining recovery values in the range 83.4-122.8%. The gliadin method was applied to the analysis of gluten-free food samples by using a previous extraction step. The recovery study gave values between 94.3 and 105.0%.

  13. Simultaneous Determination of Amlodipine Besylate and Atorvastatin Calcium in Binary Mixture by Spectrofluorimetry and HPLC Coupled with Fluorescence Detection

    OpenAIRE

    Bahia A. Moussa; Asmaa A. El-Zaher; Mahrouse, Marianne A.; Ahmed, Maha S.

    2013-01-01

    Caduet tablets are novel prescription drug that combines amlodipine besylate (AM) with atorvastatin calcium (AT). A spectrofluorimetric and an HPLC-fluorescence detection methods were developed for simultaneous determination of both drugs in tablets. In the spectrofluorimetric method, native fluorescence of AM and AT were measured in methanol at 442 and 369 nm upon excitation at 361 and 274 nm, respectively. The emission spectrum of each drug reveals zero value at the emission wavelength of t...

  14. SU-C-303-05: Photosensitizer Determination for PDT Using Interstitial and Surface Measurements of Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M; Finlay, J; Zhu, T [University of Pennsylvania, Philadelphia, PA (United States)

    2015-06-15

    Purpose: Photosensitizer concentration during photodynamic therapy (PDT) is an important parameter for accurate dosimetry. Fluorescence signal can be used as a measure of photosensitizer concentration. Two methods of data acquisition were compared to an ex vivo study both for in vivo and phantom models. Methods: Fluorescence signal of commonly used photosensitizer benzoporphyrin derivative monoacid ring A (BPD) was obtained in phantoms and mouse tumors using an excitation light of 405 nm. Interstitial fluorescence signal was obtained using a side-cut fiber inserted into the tumor tissue of interest. Using a previously developed multi-fiber probe, tumor surface fluorescence measurements were also collected. Signals were calibrated according to optical phantoms with known sensitizer fluorescence. Optical properties for each sample were determined and the influence of different absorption and scattering properties on the fluorescence signals was investigated. Using single value decomposition of the spectra, the sensitizer concentration was determined using the two different measurement geometries. An ex vivo analysis was also performed for tumor samples to determine the sensitizer concentration. Results: The two fluorescence signals obtained from the surface multi-fiber probe and the interstitial measurements were compared and were corresponding for both phantoms and mouse models. The values obtained were comparable to the ex vivo measurements as well. Despite the difference in geometry, the surface probe measurements can still be used as a metric for determining the presence of sensitizer in small volume tumors. Conclusion: The multi-fiber contact probe can be used as a tool to measure fluorescence at the surface of the treatment area for PDT and predict sensitizer concentration throughout the tumor. This is advantageous in that the measurement does not damage any tissue. Future work will include investigating the dependence of these results on intratumor sensitizer

  15. Maximum permissible concentrations of uranium in air

    CERN Document Server

    Adams, N

    1973-01-01

    The retention of uranium by bone and kidney has been re-evaluated taking account of recently published data for a man who had been occupationally exposed to natural uranium aerosols and for adults who had ingested uranium at the normal dietary levels. For life-time occupational exposure to uranium aerosols the new retention functions yield a greater retention in bone and a smaller retention in kidney than the earlier ones, which were based on acute intakes of uranium by terminal patients. Hence bone replaces kidney as the critical organ. The (MPC) sub a for uranium 238 on radiological considerations using the current (1959) ICRP lung model for the new retention functions is slightly smaller than for earlier functions but the (MPC) sub a determined by chemical toxicity remains the most restrictive.

  16. Uranium in cassiterites of tin deposits

    Energy Technology Data Exchange (ETDEWEB)

    Zagruzina, I.A.; Pinskij, Eh.M.; Savinova, I.B.

    1986-01-01

    For the purpose of elucidation of physico-chemical features of uranium and tin behaviour in ore deposition zones uranium determinations (1000 determ) in cassiterite grains from 55 tin-ore deposits of different formation types of several separate regions are carried out by means of fission radiography. It is shown that uranium content in cassiterites is a genetic sign. Peculiarities of uranium concentration and migration in tin deposits permit to use them as prognostic radiogeochemical criteria. Radiogeochemical prognostic-search signs confirm the antagonism between uranium and tin deposits of cassiterite-silicate and cassiterite-sulfide formations and paragenetic of certain types of uranium hydrothermal deposits with tin deposits of cassiterite-quartz formation.

  17. Colorimetric detection of uranium in water

    Science.gov (United States)

    DeVol, Timothy A [Clemson, SC; Hixon, Amy E [Piedmont, SC; DiPrete, David P [Evans, GA

    2012-03-13

    Disclosed are methods, materials and systems that can be used to determine qualitatively or quantitatively the level of uranium contamination in water samples. Beneficially, disclosed systems are relatively simple and cost-effective. For example, disclosed systems can be utilized by consumers having little or no training in chemical analysis techniques. Methods generally include a concentration step and a complexation step. Uranium concentration can be carried out according to an extraction chromatographic process and complexation can chemically bind uranium with a detectable substance such that the formed substance is visually detectable. Methods can detect uranium contamination down to levels even below the MCL as established by the EPA.

  18. Trace element determination in amniotic fluid by total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Greaves, E.D.; Sajo-Bohus, L.; Castelli, C.; Borgerg, C. [Universidad Simon Bolivar, Caracas (Venezuela); Meitin, J.; Liendo, J.

    1995-03-01

    A new method is reported for the determination of Fe, Cu, Zn, and Br in amniotic fluid (AF) by Total Reflection X-Ray Fluorescence. The irradiation of AF samples with monochromatic X-Rays reduces the scattering background from the organic matrix and avoids the need for sample digestion. Sample manipulation is reduced to centrifuging and adding cobalt as internal standard. Lower detection limits obtained are 109, 53, 44 and 37 ppb for Fe, Cu, Zn and Br respectively. Measurement precision depends on element concentrations and can be as low as 1.5% SD. Results of the analysis of 34 AF samples from Venezuelan pregnant patients agree with previously reported ranges of Fe, Cu and Zn. Other elements observed but not quantified are Cl, K, Ca in all spectra and Pb and Sr in some of them. (author).

  19. X-Ray Fluorescence to Determine Zn in Bolivian Children using Hair Samples

    Energy Technology Data Exchange (ETDEWEB)

    Tellería Narvaez, C.A.; Fernández Alcázar, S.; Barrientos Zamora, F.G.; Chungara Castro, J.; Luna Lauracia, I.; Mamani Tola, H.; Mita Peralta, E.; Muñoz Gosálvez, A.O. [Centro de Investigaciones y Aplicaciones Nucleares (CIAN-Viacha), Viacha (Bolivia, Plurinational State of); Romero Bolaños, L.E. [Instituto Boliviano de Ciencia y Tecnología Nuclear Av. 6 de Agosto 2905, La Paz (Bolivia, Plurinational State of); Ramírez Ávila, G.M., E-mail: gramirez@ulb.ac.be [Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, Campus Universitario Cota Cota, Casilla 8635, La Paz (Bolivia, Plurinational State of)

    2014-06-15

    As a first step in the evaluation of nutritional levels in Bolivian children (8–13 years-old), we carried out X-Ray Fluorescence measurements in hair samples of children belonging to different social classes and living either in rural areas or in cities. The aim of this study is to contribute to health policies tending to improve the global health of children and consequently avoid malnutrition. Our method intends to have maximum reliability and at the same time be as simple as possible from an experimental point of view. Additionally, we use this method to determine some other elements such as Fe, Cu, Pb, As and Hg, the latter three considered as contaminants that could be present in children living in areas which neighbor mines and industries. This work will be complemented by some biological and medical tests.

  20. Metals determination in wood treated by synchrotron radiation X-ray fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Silva, Richard Maximiliano da Cunha [Centro de Energia Nuclear na Agricultura, Piracicaba, SP (Brazil)]. E-mail: maxcunha@cena.usp.br; Medeiros, Jean Gabriel da Silva; Tomazello Filho, Mario [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz]. E-mail: jeangm@esalq.usp.br; mtomazel@esalq.usp.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Zucchi, Orgheda Luiza Araujo Domingues [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Barroso, Regina Cely [Universidade do Estado, Rio de Janeiro, RJ (Brazil)]. E-mail: cely@uerj.br

    2005-07-01

    The paper describes the use of X-Ray fluorescence analysis for distribution and quantification of metals in the hardwood (Eucalyptus sp) and softwood (Pinus sp) treated with CCA (copper-chromium-arsenic). The sapwood/heartwood for hardwood sample and the growth-rings for softwood sample were analyzed. The samples were scanned in 320 mm steps in the vertical direction. For excitation of the elements a white beam synchrotron radiation of {approx} 320 x 180 mm was employed and for the X-ray detection a Si(Li) semiconductor detector. The elements K, Ca, Cr, Mn, Cu, Zn and As were determined. Fundamental parameters were used to quantify the elements concentrations. (author)

  1. Determination of the biodiesel content in diesel/biodiesel blends: a method based on fluorescence spectroscopy.

    Science.gov (United States)

    Scherer, Marisa D; Oliveira, Samuel L; Lima, Sandro M; Andrade, Luis H C; Caires, Anderson R L

    2011-05-01

    Blends of biodiesel and diesel are being used increasingly worldwide because of environmental, economic, and social considerations. Several countries use biodiesel blends with different blending limits. Therefore, it is necessary to develop or improve methods to quantify the biodiesel level in a diesel/biodiesel blend, to ensure compliance with legislation. The optical technique based on the absorption of light in the mid-infrared has been successful for this application. However, this method presents some challenges that must be overcome. In this paper, we propose a novel method, based on fluorescence spectroscopy, to determine the biodiesel content in the diesel/biodiesel blend, which allows in loco measurements by using portable systems. The results showed that this method is both practical and more sensitive than the standard optical method. © Springer Science+Business Media, LLC 2011

  2. Determination of adenosine disodium triphosphate (ATP) using norfloxacin-Tb{sup 3+} as a fluorescence probe by spectrofluorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Miao Yanhong [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); College of Science and Technology, Shandong Agriculture University, Taian 271000 (China); Liu Jinkai [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); Hou Faju [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); Jiang Chongqiu [Department of Chemistry, Shandong Normal University, Jinan 250014 (China)]. E-mail: jiangchongqiu@sdnu.edu.cn

    2006-01-15

    A new spectrofluorimetric method was developed for determination of trace amount of adenosine disodium triphosphate (ATP). Using norfloxacin (NFLX)-terbium (Tb{sup 3+}) as a fluorescent probe, in the buffer solution of pH=7.40, ATP can remarkably enhance the fluorescence intensity of the NFLX-Tb{sup 3+} complex at {lambda}=545nm and the enhanced fluorescence intensity of Tb{sup 3+} ion is in proportion to the concentration of ATP. Optimum conditions for the determination of ATP were also investigated. The dynamic range for the determination of ATP is 1.00x10{sup -6}-1.60x10{sup -5}mol/L with detection limit of 4.13x10{sup -8}mol/L. This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of ATP in samples.

  3. Uranium processing and properties

    CERN Document Server

    2013-01-01

    Covers a broad spectrum of topics and applications that deal with uranium processing and the properties of uranium Offers extensive coverage of both new and established practices for dealing with uranium supplies in nuclear engineering Promotes the documentation of the state-of-the-art processing techniques utilized for uranium and other specialty metals

  4. 用卡氏库仑法测定二氧化铀中的水分%Determination of water content in uranium dioxide with Karl Fisher coulometer

    Institute of Scientific and Technical Information of China (English)

    王春叶; 杜桂荣; 谢树军; 李晓红; 朱小良

    2011-01-01

    The method of determining water content in uranium dioxide with Karl Fisher coulometer is introduced, and the instrument conditions were optimized. Air is taken as carrier gas, carrier gas f low rate is 40-60 mL/min, the temperature of Cassette furnace is 200 ℃, stirring rate of titration cell is 300-900 r/min, the extraction time is 800 s. Under the above conditions, water content in uranium dioxide was determined. The detection limit of the method is 38 μg/g, the relative standard deviation is less than 1. 76%(n = 6), and standard addition recovery is 93. 6%-99.1%.%介绍测定二氧化铀中水分的卡尔费休库仑法及条件参数的优化.采用以下条件参数对二氧化铀中的水分进行测定:空气作载气,载气流速为60 mL/min,卡氏炉温度为200℃,滴定池的搅拌速度为600 r/min,萃取时间为800 s.方法检出限为38 μg/g,6次平行测定的相对标准偏差为1.76%,标准加入的回收率为93.6%~99.1%.

  5. Determination of Uranium and Thorium in Water by N-235 extraction/Spectrophotometric Method%N-235萃取/分光光度法测定水中铀和钍

    Institute of Scientific and Technical Information of China (English)

    周花珑; 甘毓璘; 黄彬丽

    2012-01-01

      用N-235作为萃取剂,偶氮砷Ⅲ作为显色剂,用分光光度法测定水中的铀和钍。结果表明:铀、钍的回收率在80%以上,方法稳定可靠。%  With N-235 as the extraction and Azo arsenic Ⅲ as the chromogenic reagent, Uranium and Thorium in the water were determined by spectrophotometry. The results showed that the recoveries of Uranium and Thorium were above 80%,the method is stable and reliable.

  6. Method 445.0 In Vitro Determination of Chlorophyll a and Pheophytin ain Marine and Freshwater Algae by Fluorescence

    Science.gov (United States)

    This method provides a procedure for low level determination of chlorophyll a (chl a) and its magnesium free derivative, pheophytin a (pheo a), in marine and freshwater phytoplankton using fluorescence detection.(1,2) Phaeophorbides present in the sample are determined collective...

  7. Method 445.0 In Vitro Determination of Chlorophyll a and Pheophytin ain Marine and Freshwater Algae by Fluorescence

    Science.gov (United States)

    This method provides a procedure for low level determination of chlorophyll a (chl a) and its magnesium free derivative, pheophytin a (pheo a), in marine and freshwater phytoplankton using fluorescence detection.(1,2) Phaeophorbides present in the sample are determined collective...

  8. Ratiometric fluorescent paper sensor utilizing hybrid carbon dots-quantum dots for the visual determination of copper ions

    Science.gov (United States)

    Wang, Yahui; Zhang, Cheng; Chen, Xiaochun; Yang, Bo; Yang, Liang; Jiang, Changlong; Zhang, Zhongping

    2016-03-01

    A simple and effective ratiometric fluorescence nanosensor for the selective detection of Cu2+ has been developed by covalently connecting the carboxyl-modified red fluorescent cadmium telluride (CdTe) quantum dots (QDs) to the amino-functionalized blue fluorescent carbon nanodots (CDs). The sensor exhibits the dual-emissions peaked at 437 and 654 nm, under a single excitation wavelength of 340 nm. The red fluorescence can be selectively quenched by Cu2+, while the blue fluorescence is a internal reference, resulting in a distinguishable fluorescence color change from pink to blue under a UV lamp. The detection limit of this highly sensitive ratiometric probe is as low as 0.36 nM, which is lower than the U.S. Environmental Protection Agency (EPA) defined limit (20 μM). Moreover, a paper-based sensor has been prepared by printing the hybrid carbon dots-quantum dots probe on a microporous membrane, which provides a convenient and simple approach for the visual detection of Cu2+. Therefore, the as-synthesized probe shows great potential application for the determination of Cu2+ in real samples.A simple and effective ratiometric fluorescence nanosensor for the selective detection of Cu2+ has been developed by covalently connecting the carboxyl-modified red fluorescent cadmium telluride (CdTe) quantum dots (QDs) to the amino-functionalized blue fluorescent carbon nanodots (CDs). The sensor exhibits the dual-emissions peaked at 437 and 654 nm, under a single excitation wavelength of 340 nm. The red fluorescence can be selectively quenched by Cu2+, while the blue fluorescence is a internal reference, resulting in a distinguishable fluorescence color change from pink to blue under a UV lamp. The detection limit of this highly sensitive ratiometric probe is as low as 0.36 nM, which is lower than the U.S. Environmental Protection Agency (EPA) defined limit (20 μM). Moreover, a paper-based sensor has been prepared by printing the hybrid carbon dots-quantum dots probe on a

  9. [Determination of mercury in shark liver by cold atom fluorescence spectrometry after microwave dissolution].

    Science.gov (United States)

    Weng, Di

    2005-12-01

    The conditions for the determination of mercury in shark liver by cold atom fluorescence spectrometry (CAFS) with microwave dissolution were studied. After being dried completely, the method employed 2 mol x L(-1) HNO3-4 mol x L(-1) HCl as an oxidant, and with catalysis by V2O5, the samples were digested in a microwave oven. The mercury in absorption solution was reduced by SnCl2, and then was determined by CAFS at wavelength of 253.7 nm. 10% SnCl2 solution was used as a reductive agent for mercury. The linear range was 0-2.0 ng x mL(-1) mercury (r = 0.999 7). The detection limit was 0.05 ng x mL(-1), the relative standard deviation was 0.86%-2.22%, and the average recovery rate was 96.0%-108.5%. The method was suitable for the determination of mercury in shark liver.

  10. Determination of cadmium at ultra-trace levels by CPE-molecular fluorescence combined methodology

    Energy Technology Data Exchange (ETDEWEB)

    Talio, Maria Carolina [Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Luconi, Marta O. [Area de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Masi, Adriana N. [Area de Bromatologia- Ensayo y Valoracion de Medicamentos, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Fernandez, Liliana P., E-mail: lfernand@unsl.edu.ar [Area de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina)

    2009-10-15

    A highly sensitive micelle-mediated extraction methodology for the preconcentration and determination of trace levels of cadmium by molecular fluorescence has been developed. Metal was complexed with o-phenanthroline (o-phen) and eosin (eo) at pH 7.6 in buffer Tris medium and quantitatively extracted into a small volume of surfactant-rich phase of PONPE 7.5 after centrifugating. The chemical variables affecting cloud point extraction (CPE) were evaluated and optimized. The RSD for six replicates of cadmium determinations at 0.84 {mu}g L{sup -1} level was 1.17%. The linearity range using the preconcentration system was between 2.79 x 10{sup -3} {mu}g L{sup -1} and 2.81 {mu}g L{sup -1} with a correlation coefficient of 0.99. Under the optimal conditions, it obtained a LOD of 8.38 x 10{sup -4} {mu}g L{sup -1} and LOQ of 2.79 x 10{sup -3} {mu}g L{sup -1}. The method presented good sensitivity and selectivity and was applied to the determination of trace amounts of cadmium in commercially bottled mineral water, tap water and water well samples with satisfactory results. The proposed method is an innovative application of CPE-luminescence to metal analysis comparable in sensitivity and accuracy with atomic spectroscopies.

  11. Novel Method for Indirect Determination of Iodine in Marine Products by Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LU Jian-ping; TAN Fang-wei; TANG Qiong; JIANG Tian-cheng

    2013-01-01

    A method for the determination of iodine based upon compound H2HgI4,formed between I-and Hg2+ in nitric acid and extracted in methyl isobutyl ketone(MIBK),was developed via atomic fluorescence spectrometry(AFS).After the compound is reduced with potassium borohydrid(KBH4),the resultant mercury vapor was injected into the instrument and iodine was,therefore,indirectly determined.Experimental parameters such as the conditions of extraction reagents,aqueous phase acidity,elemental mercury diffusion temperature in a vial and other factors were investigated and optimized.Under the optimum experimental conditions,this method shows a detection limit of 0.038 μg/L iodine and a linear relationship between 0.04-20 μg/L.The method was applied to determining the iodine content in marine duck eggs,kelps,laver and Ganoderma lucidum spirulina,showing a relative standard deviation(RSD) of 2.15% and the recoveries in the range of 98.1%-102.5%.

  12. Determination of Ca/P molar ratio in hydroxyapatite (HA) by X-ray fluorescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Scapin, Marcos A.; Guilhen, Sabine N.; Cotrim, Marycel E.B.; Pires, Maria Ap. F., E-mail: mascapin@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Hydroxyapatite (HA) is a mineral composed of calcium phosphate employed for endodontics, restorative dentistry and other applications in orthopedics and prosthesis. Additionally, this biomaterial is an inexpensive but efficient adsorbent for the removal of heavy metals and other unwanted species of contaminated liquid effluents. This is especially interesting when low-cost effective remediation is required. A Ca / P molar ratio of 1.667 is consistent with the theoretical Ca / P ratio for calcium hydroxyapatite with a compositional formula of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, which properties are well discussed in the literature. The aim of this work was to implement and validate a methodology for simultaneous determination of major and minor constituents in the hydroxyapatite (HA) as well as providing the Ca / P molar ratio. To accomplish these achievements, wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) was applied. This is a non-destructive technique that requires no chemical treatment, enabling fast chemical analysis in a wide variety of samples, with no hazardous waste being generated as a result of the process of determination. A standard reference material from NIST (SRM 1400 – Bone Ash) was used to validate the methodology for the determination of magnesium, phosphorus, potassium, calcium, iron, zinc, strontium and the Ca / P ratio in HA samples by WDXRF. The Z-score test was applied as a statistical tool and showed that the calculated values were of less than 1.8 for all the measured analytes. (author)

  13. Coupling of Uranium and Thorium Series Isotope Systematics for Age Determination of Late Pleistocene Zircons using LA-ICP-MS

    Science.gov (United States)

    Sakata, S.; Hirakawa, S.; Iwano, H.; Danhara, T.; Hirata, T.

    2014-12-01

    Zircon U-Th-Pb dating method is one of the most important tools for estimating the duration of magmatism by means of coupling of uranium, actinium and thorium decay series. Using U-Pb dating method, its reliability is principally guaranteed by the concordance between 238U-206Pb and 235U-207Pb ages. In case of dating Quaternary zircons, however, the initial disequilibrium effect on 230Th and 231Pa should be considered. On the other hands, 232Th-208Pb dating method can be a simple but powerful approach for investigating the age of crystallization because of negligible influence from initial disequilibrium effect. We have developed a new correction model for accurate U-Pb dating of the young zircon samples by taking into consideration of initial disequilibrium and a U-Pb vs Th-Pb concordia diagram for reliable age calibration was successfully established. Hence, the U-Th-Pb dating method can be applied to various zircons ranging from Hadean (4,600 Ma) to Quaternary (~50 ka) ages, and this suggests that further detailed information concerning the thermal history of the geological sequences can be made by the coupling of U-Th-Pb, fission track and Ar-Ar ages. In this presentation, we will show an example of U-Th-Pb dating for zircon samples from Sambe Volcano (3 to 100 ka), southwest Japan and the present dating technique using LA-ICP-MS.

  14. Combination of solid phase extraction and dispersive liquid–liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination

    Energy Technology Data Exchange (ETDEWEB)

    Dadfarnia, Shayessteh, E-mail: sdadfarnia@yazd.ac.ir; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-12-15

    Graphical abstract: Pass the sample through the basic alumina column ⇒ elute retained uranium along with the cations ⇒ convert the uranium to its anionic benzoate complex ⇒ extract its ion pair with malachite green into small volume of chloroform by DLLME ⇒ measure its absorption at 621 nm using fiber optic-linear array detection spectrophotometry. -- Highlights: • By combination of SPE and DDLME a high preconcentration factor of 2500 was obtained. • Development of SPE-DDLME-Spectrophotometric method for det. of trace amounts of uranium. • Ultra trace amount of uranium in water samples was det. by the proposed method. • The detection limit of the proposed method is comparable to the most sensitive method. • The proposed method is a free interference spectrophotometric method for uranium det. -- Abstract: A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid–liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L{sup −1}) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid–liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L{sup −1}, and a relative standard deviation of 4.1% (n = 6) at 400 ng L{sup −1} were obtained. The

  15. Determination of closantel residues in plasma and tissues by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Stoev, G

    1998-06-12

    The influence of the pH of the mobile phase with some modifiers on the chromatographic behavior and fluorescence properties of closantel have been investigated. At acidic pH values (2-6), the benzamide moiety of the closantel forms a six-membered ring by hydrogen bonding and possesses a native fluorescence. Using the fluorescence emission of closantel at lambda(ex) = 335 nm, lambda(em) = 510 nm, and pH 2.5 of the mobile phase, a linear calibration curve was estimated over a concentration range of about two orders of magnitude with a correlation coefficient larger than 0.992. The limit of the fluorescence detection was 10 microg/kg. This value was at least 10 times lower than that using UV detection. The method was applied to the determination of closantel in plasma and tissue samples, purified by a solid-phase extraction with C18 cartridges.

  16. 野外现场铀矿石中铀的快速准确测定方法研究——TOPO萃取α计数法%Rapid and Accurate Determination of Uranium in Uranium Ores in the Field Using TOPO Extraction and α-counting Method

    Institute of Scientific and Technical Information of China (English)

    黄秋红; 刘立坤; 郭冬发; 王玉学; 武朝晖; 汤三星; 李红光

    2011-01-01

    研究了野外现场快速准确测定铀矿石中铀的三辛基氧膦(TOPO)萃取α计数法.目前野外现场铀的测量主要采用γ谱法,即利用铀子体的γ射线强度来计算铀的含量,当样品中铀镭处于不平衡状态时,γ谱法测铀存在着较大的测量误差.本文将铀的核性质与化学性质结合起来,采用密闭酸溶法快速溶解样品中的铀,酸溶后的样品不经分离直接在溶样罐中用TOPO萃取,进而测定样品中铀产生的α射线强度获得铀的含量,避免了γ谱法的不足.方法检出限为铀含量2.41 μg/g;当铀含量为大约为100μg/g时,测量相对偏差为5.93%;铀的测定范围为7.23μg/g~ n%.密闭酸溶法试剂用量少,溶样速度快,且对环境和操作人员污染小;酸溶后的样品用TOPO萃取2 min后即可达到萃取平衡,铀萃取效率在97%以上;所需的仪器设备可以车载形式用于野外现场铀矿石中铀的准确测定,野外应用操作简单、快速、精密度和准确性较高.%The method of TOPO extraction followed by a-counting has been developed for field determination of uranium in uranium ores. The traditional method of field uranium determination is by spectrometry. The content of uranium using that method is determined by the intensity of the ray, therefore, results have larger errors when uranium and radium are in equilibrium. The method researched by this article combines the nuclear and chemical properties of uranium. The content of the uranium is determined directly by the intensity recorded by an a counter after following dissolution and extraction processes. The detection limit of uranium is 2.41 μg/g. When the content of uranium is about 100 μg/g, the relative standard deviation ( RSD) is 5. 93% . The determining range of uranium is 7. 23 μg/g - n%. The dissolution method requires less reagents, has better dissolving efficiency and less pollution. The extraction method has the advantage and efficiency ( >97

  17. Application of magnetic and core-shell nanoparticles to determine enrofloxacin and its metabolite using laser induced fluorescence microscope.

    Science.gov (United States)

    Kim, Suji; Ko, Junga; Lim, H B

    2013-04-10

    A unique analytical method using nanoparticles and laser-induced fluorescence microscopy (LIFM) was developed to determine enrofloxacin in this work. For sample pretreatment, two different kinds of particles, i.e., synthesized dye-doped core-shell silica nanoparticles and magnetic micro-particles (MPs), were used for fluorescent tagging and concentrating the enrofloxacin, respectively. The antibody of enrofloxacin was immobilized on the synthesized FITC-doped core-shell nanoparticles, and the enrofloxacin target was extracted by the MPs. At this moment, the average number of antibodies on each core-shell silica nanoparticle was ~0.9, which was determined by the fluorescence ratiometric method. The described method was demonstrated for a meat sample to determine enrofloxacin using LIFM, and the result was compared with enzyme-linked immunosorbent assay (ELISA). The developed technique allowed the simplified analytical procedure, improved the detection limit about 54-fold compared to ELISA.

  18. Interaction of uranium with Pleurotus sp.

    Energy Technology Data Exchange (ETDEWEB)

    Ohnuki, Toshihiko; Sakamoto, Fuminori; Kozaki, Naofumi; Ozaki, Takuro; Samadfam, Mohammad [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-11-01

    Uptake of uranium by higher fungi, such as mushroom is little elucidated. We have studied the interaction of uranium with Pleurotus sp. (a mushroom) in pure culture over a wide range of U concentration (50-3000 mg/L). The Pleurotus sp. was cultured in two different media. One was rice bran medium, and the other was agar (yeast extract, peptone and dextrose) medium. The uptake of uranium in Pleurotus sp. was examined by alpha ray autoradiography (A,A), X-ray fluorescence spectroscopy (XRF) and scanning microcopy (SEM) equipped with EDS. In the agar medium, the higher uranium concentration gave lower growth of mycelia, and no fruiting body was observed. In the rice bran medium, the fruiting body was grown at U concentrations up to 1000 mg/L. The AA and XRF analysis showed that uranium taken up in the fruiting body was below the detection limit. The SEM-EDS analysis indicated that U was distributed in the limited region and was not transported to the mycelia far from U containing medium. It is concluded that uranium affects the growth of Pleurotus sp., and little uranium is taken up by Pleurotus sp. during the growth of both mycelia and fruiting body. (author)

  19. 78 FR 75579 - Low Enriched Uranium From France

    Science.gov (United States)

    2013-12-12

    ... COMMISSION Low Enriched Uranium From France Determination On the basis of the record \\1\\ developed in the... antidumping duty order on low enriched uranium from France would be likely to lead to continuation or...), entitled Low Enriched Uranium from France: Investigation No. 731-TA-909 (Second Review). By order of...

  20. Determination of flumioxazin residue in food samples through a sensitive fluorescent sensor based on click chemistry.

    Science.gov (United States)

    Lu, Lijun; Yang, Linlin; Cai, Huijian; Zhang, Lan; Lin, Zhenyu; Guo, Longhua; Qiu, Bin; Chen, Guonan

    2014-11-01

    A sensitive and selective fluorescent sensor for flumioxazin was designed based on the formation of strong fluorescence compound (1,2,3-triazole compounds) via the reaction of the alkynyl group in flumioxazin with 3-azido-7-hydroxycoumarin, a weak-fluorescent compound, through the Cu(+)-catalysed azide-alkyne cycloaddition (CuAAC) reaction. The fluorescence increase factor (represented by F/F0) of the system exhibited a good linear relationship with the concentrations of flumioxazin in the range of 0.25-6.0 μg/L with a detection limit of 0.18 μg/L (S/N=3). Also, the proposed fluorescent sensor demonstrated good selectivity for flumioxazin assay even in the presence of high concentration of other pesticides. Based on such high sensitivity and selectivity, the proposed fluorescent sensor has been applied to test the flumioxazin residue in some vegetable and water samples with satisfied results.

  1. A simple fluorescence quenching method for berberine determination using water-soluble CdTe quantum dots as probes

    Science.gov (United States)

    Cao, Ming; Liu, Meigui; Cao, Chun; Xia, Yunsheng; Bao, Linjun; Jin, Yingqiong; Yang, Song; Zhu, Changqing

    2010-03-01

    A novel method for the determination of berberine has been developed based on quenching of the fluorescence of thioglycolic acid-capped CdTe quantum dots (TGA-CdTe QDs) by berberine in aqueous solutions. Under optimum conditions, the relative fluorescence intensity was linearly proportional to the concentration of berberine between 2.5 × 10 -8 and 8.0 × 10 -6 mol L -1 with a detection limit of 6.0 × 10 -9 mol L -1. The method has been applied to the determination of berberine in real samples, and satisfactory results were obtained. The mechanism of the proposed reaction was also discussed.

  2. Morphology Characterization of Uranium Particles From Laser Ablated Uranium Materials

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the study, metallic uranium and uranium dioxide material were ablated by laser beam in order to simulate the process of forming the uranium particles in pyrochemical process. The morphology characteristic of uranium particles and the surface of

  3. Ultrasensitive techniques for measurement of uranium in biological samples and the nephrotoxicity of uranium: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Kathren, R.L.; Weber, J.R. (eds.)

    1988-04-01

    Edited transcripts are provided of two public meetings sponsored by the Division of Radiation Programs and Earth Sciences of the Nuclear Regulatory Commission, Occupational Radiation Protection Branch. The first meeting, held on December 3, 1985, included nine presentations covering ultrasensitive techniques for measurement of uranium in biological specimens. Topics included laser-spectrometric techniques for uranium bioassay, correlation of urinary uranium samples with air sampling results in industrial settings, delayed neutron counting, laser-kinetic phosphometry, isotope dilution mass spectrometry, resonance ionization spectroscopy, fission track analysis, laser-induced fluorescence, and costs of sampling and processing. The nine presentations of the second meeting dealt with the nephrotoxicity of uranium. Among the topics presented were the physiology of the kidney, the effects of heavy metals on the kidney, animal studies in uranium nephrotoxicity, comparisons of kidney histology in nine humans, renal effects in uranium mill workers, renal damage from different uranium isotopes, and Canadian studies on uranium toxicity. Discussions following the presentations are included in the edited transcripts. 30 refs., 9 figs., 9 tabs.

  4. Determination of inorganic species of Sb and Te in cereals by hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Mariela N.M.; Cervera, Maria L.; Guardia, Miguel de la, E-mail: m.luisa.cervera@uv.e [University of Valencia, Valencia (Spain). Dept. of Analytical Chemistry

    2011-07-01

    A non-chromatographic fast, sensitive and easy method has been developed for the determination of Sb(III), Sb(V), Te(IV) and Te(VI) in cereal samples. The procedure is based on ultrasound assisted extraction and determination by hydride generation atomic fluorescence spectrometry (HG AFS). Preliminary studies were made in order to get the best extraction efficiency using 1 mol L{sup -1} phosphoric acid, 1 mol L{sup -1} nitric acid, aqua regia, 1 mol L{sup -1} sulfuric acid and 6 mol L{sup -1} hydrochloric acid. The extraction with aqua regia showed a clear interconversion of the species during the process, being H{sub 2}SO{sub 4} the best extractant with efficiencies greater than 90% from the total content of Sb and Te quantified previously and without species interconversion. This point was checked by recovery experiments at different spiked levels. The method provided limits of detection values from 0.1 to 0.5 ng g{sup -1} with relative standard deviation values from 5.4 to 9.2% of 10 independent analysis of samples containing few ng g-1 of Sb and Te species. (author)

  5. [Determination of 22 Elements in Herb Tea by X-Ray Fluorescence Spectrometry].

    Science.gov (United States)

    Li, Dan; Ge, Liang-quan; Wang, Guang-xi; Lai, Wan-chang; Zhai, Juan; Chen, Lu

    2015-07-01

    N, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Ba and Pb in herb tea were determined by X-ray fluorescence spectrometry with pressed powder pellets. The measuring conditions of target elements were investigated, including how to select its analytical line. In addition to Ba and Pb using L line, Kalpha line was selected for the rest. When the Compton scattered radiation of Rh Kalpha was measured, The X-ray tube voltage should be appropriately reduced, and the appropriate tube current should be selected. The matrix effect was corrected by empirical coefficient method and using scattered radiation (the Rayleigh scattered radiation of Rh Lalpha, the scattered background of 0.1876 nm wavelength position and the Compton scattered radiation of Rh Kalpha) as internal standard, and the spectral overlapping interference of some elements (N, Na, Ca, Ti, Mn, Sr and Ba) was corrected. For the target elements, the detection limit of this method was low, and its accuracy and precision were high. The results showed that there were abandon of elements in herb tea, of which different kinds had different components, even the same kind of herb tea with different source had some difference in element and content more or less, however, there was a lot of similarity between the features of its components. In a word, this method could achieve multi-element determination of herb tea, and it was simple in operation, low cost, rapid, and accurate.

  6. Determination of gamma-ray widths in $^{15}$N using nuclear resonance fluorescence

    CERN Document Server

    Szücs, T; Caciolli, A; Fülöp, Zs; Massarczyk, R; Michelagnoli, C; Reinhardt, T P; Schwengner, R; Takács, M P; Ur, C A; Wagner, A; Wagner, L

    2015-01-01

    The stable nucleus $^{15}$N is the mirror of $^{15}$O, the bottleneck in the hydrogen burning CNO cycle. Most of the $^{15}$N level widths below the proton emission threshold are known from just one nuclear resonance fluorescence (NRF) measurement, with limited precision in some cases. A recent experiment with the AGATA demonstrator array determined level lifetimes using the Doppler Shift Attenuation Method (DSAM) in $^{15}$O. As a reference and for testing the method, level lifetimes in $^{15}$N have also been determined in the same experiment. The latest compilation of $^{15}$N level properties dates back to 1991. The limited precision in some cases in the compilation calls for a new measurement in order to enable a comparison to the AGATA demonstrator data. The widths of several $^{15}$N levels have been studied with the NRF method. The solid nitrogen compounds enriched in $^{15}$N have been irradiated with bremsstrahlung. The $\\gamma$-rays following the deexcitation of the excited nuclear levels were dete...

  7. Determination of total plasma hydroperoxides using a diphenyl-1-pyrenylphosphine fluorescent probe.

    Science.gov (United States)

    Santas, Jonathan; Guardiola, Francesc; Rafecas, Magda; Bou, Ricard

    2013-03-01

    Plasma hydroperoxides (HPs) are widely accepted to be good indicators of oxidative stress. By means of the method proposed here, which uses diphenyl-1-pyrenylphosphine (DPPP) as a fluorescent probe, all types of plasma HP were determined. The limits of detection and quantification of the method were 0.08 and 0.25 nmol of cumene hydroperoxide (CHP) equivalents in 40 μl of plasma, respectively. The method is satisfactory in terms of precision (5.3% for 14.5 μM CHP eq., n=8), and the recoveries were 91% and 92% after standard additions of 26 and 52 μM CHP, respectively. The selectivity of the proposed method is higher than 96%. Moreover, optimization of the reaction conditions and the addition of ethylenediaminetetraacetic acid (EDTA) disodium salt and 2,6-di-tert-butyl-4-methylphenol (BHT) prevented the formation of HP artifacts during the analysis. Therefore, the proposed method is useful for simple and quantitative determination of total plasma HPs.

  8. Determination of element levels in human serum: Total reflection X-ray fluorescence applications

    Science.gov (United States)

    Majewska, U.; Łyżwa, P.; Łyżwa, K.; Banaś, D.; Kubala-Kukuś, A.; Wudarczyk-Moćko, J.; Stabrawa, I.; Braziewicz, J.; Pajek, M.; Antczak, G.; Borkowska, B.; Góźdź, S.

    2016-08-01

    Deficiency or excess of elements could disrupt proper functioning of the human body and could lead to several disorders. Determination of their concentrations in different biological human fluids and tissues should become a routine practice in medical treatment. Therefore the knowledge about appropriate element concentrations in human organism is required. The purpose of this study was to determine the concentration of several elements (P, S, Cl, K, Ca, Cr, Fe, Cu, Zn, Se, Br, Rb, Pb) in human serum and to define the reference values of element concentration. Samples of serum were obtained from 105 normal presumably healthy volunteers (66 women aged between 15 and 78 years old; 39 men aged between 15 and 77 years old). Analysis has been done for the whole studied population and for subgroups by sex and age. It is probably first so a wide study of elemental composition of serum performed in the case of Świętokrzyskie region. Total reflection X-ray fluorescence (TXRF) method was used to perform the elemental analysis. Spectrometer S2 Picofox (Bruker AXS Microanalysis GmbH) was used to identify and measure elemental composition of serum samples. Finally, 1st and 3rd quartiles were accepted as minimum and maximum values of concentration reference range.

  9. A Validated High-Throughput Fluorometric Method for Determination of Omeprazole in Quality Control Laboratory via Charge Transfer Sensitized Fluorescence.

    Science.gov (United States)

    Mahmoud, Ashraf M; Ahmed, Sameh A

    2016-03-01

    A high-throughput 96-microwell plate fluorometric method was developed and validated to determine omeprazole (OMZ) in its dosage forms. The method was based on the charge-transfer (CT) sensitized fluorescence reaction of OMZ with 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ). This fluorescence reaction provided a new approach for simple, sensitive and selective determinations of OMZ in pharmaceutical preparations. In the present method, the fluorescence reaction was carried out in 96-microwell plates as reaction vessels in order to increase the automation of the methodology and the efficiency of its use in quality control laboratories. All factors affecting the fluorescence reaction were carefully studied and the conditions were optimized. The stoichiometry of the fluorescence reaction between OMZ and DDQ was determined and the reaction mechanism was suggested. Under the optimum conditions, the linear range was 100-6000 ng/ml with the lowest LOD of 33 ng/ml. Analytical performance of the proposed assay, in terms of accuracy and precision, was statistically validated and the results were satisfactory; RSD was <2.6 % and the accuracy was 98.6-101.6 %. The method was successfully applied to the analysis of OMZ in its dosage forms; the recovery values were 98.26-99.60 ± 0.95-2.22 %. The developed methodology may provide a safer, automated and economic tool for the analysis of OMZ in quality control laboratories.

  10. Fluorescence quenching and spectrophotometric methods for the determination of daunorubicin with meso-tera (4-sulphophenyl) porphyrin as probe.

    Science.gov (United States)

    Tian, Jing; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Zhu, Jinghui; Qiao, Man; Hu, Xiaoli

    2014-01-01

    In this work, a synthetic meso-tera (4-sulfophenyl) porphyrin (TPPS4) was used as a probe to determine daunorubicin (DNR) by fluorescence quenching and spectrophotometric methods. At pH 4.6 potassium acid phthalate-NaOH buffer solution, a 1:1 complex of DNR interacted with TPPS4 formed via the electrostatic attractions and hydrophobic interactions, thus resulted in TPPS4 fluorescence quenching and absorption spectra change. The maximum excitation wavelength (λex) and the maximum emission wavelength (λem) are 435 nm and 672 nm, respectively. The fluorescence quenching values (ΔF) are the good linear relationship to the concentration of DNR in the range of 0.8-6.0 mgL(-1). The method exhibits high sensitivity with the detection limit (3σ) being 27.0 ng mL(-1). Meanwhile, a decrease of absorbance is detected at 433 nm with the appearance of a new absorption peak at 420 nm. The optimum reaction conditions, influencing factors and the effect of coexisting substances have been investigated in our experiment. The results showed that the method had a good selectivity and could be applied to determine DNR in serum and urine samples. In addition, the combine ratio between DNR and TPPS4 was measured and the charge distribution before and after reaction was calculated by quantum chemistry calculation AM1 method. The type of fluorescence quenching was discussed by the absorption spectra change, Stern-Volmer plots and fluorescence lifetime determination.

  11. U(IV) fluorescence spectroscopy. A new speciation tool

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Susanne; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    We combined absorption and fluorescence spectroscopy to study the speciation of U(IV) in solution in concentrations down to 10{sup -6} M uranium. With our time-resolved laser-induced fluorescence setup we could determine the fluorescence decay time of U(IV) in perchloric as well as in chloric acid with 2.6 ± 0.3 ns at room temperature and 148.4 ± 6.5 ns at liquid nitrogen temperature. For the U(IV) sulfate system, we observed a bathochromic shift and a peak shape modification in the fluorescence spectra with increasing sulfate concentration in solution. Thus, the potential of U(IV) fluorescence for speciation analysis could be proven.

  12. Ratiometric fluorescent paper sensor utilizing hybrid carbon dots-quantum dots for the visual determination of copper ions.

    Science.gov (United States)

    Wang, Yahui; Zhang, Cheng; Chen, Xiaochun; Yang, Bo; Yang, Liang; Jiang, Changlong; Zhang, Zhongping

    2016-03-21

    A simple and effective ratiometric fluorescence nanosensor for the selective detection of Cu(2+) has been developed by covalently connecting the carboxyl-modified red fluorescent cadmium telluride (CdTe) quantum dots (QDs) to the amino-functionalized blue fluorescent carbon nanodots (CDs). The sensor exhibits the dual-emissions peaked at 437 and 654 nm, under a single excitation wavelength of 340 nm. The red fluorescence can be selectively quenched by Cu(2+), while the blue fluorescence is a internal reference, resulting in a distinguishable fluorescence color change from pink to blue under a UV lamp. The detection limit of this highly sensitive ratiometric probe is as low as 0.36 nM, which is lower than the U.S. Environmental Protection Agency (EPA) defined limit (20 μM). Moreover, a paper-based sensor has been prepared by printing the hybrid carbon dots-quantum dots probe on a microporous membrane, which provides a convenient and simple approach for the visual detection of Cu(2+). Therefore, the as-synthesized probe shows great potential application for the determination of Cu(2+) in real samples.

  13. Ion chromatographic method for the simultaneous determination of nitrite and nitrate by post-column indirect fluorescence detection.

    Science.gov (United States)

    Stalikas, Constantine D; Konidari, Constantina N; Nanos, Christos G

    2003-06-20

    This short paper highlights the suitability of ion chromatography with post-column indirect fluorescence detection to determine simultaneously nitrite and nitrate based on the quenching of tryptophan native fluorescence. The method uses an enhanced fluorescence mobile phase containing tryptophan and detects the suppression of fluorescence of the mobile phase due to the elution of the target ions. The phenomenon of fluorescence quenching of tryptophan is highly induced by the presence of phosphate ions. The quenched fluorescence intensity exhibits concentration dependence in the range 1-25 mg/l and 3-65 mg/l for nitrite and nitrate, respectively. The relative standard deviation for five replicates of a standard solution containing a mixture of 5 mg/l of nitrite and 10 mg/l of nitrate lies around 2.8%. This simple coupling technique results in a relatively sensitive, fast, and accurate method, allowing for both qualitative and quantitative analysis of nitrite and nitrate. The method can easily be implemented to real samples such as foodstuffs, fertilizers and soils and is proven to be precise and accurate when compared with reference methods.

  14. Hue-shifted monomeric variants of Clavularia cyan fluorescent protein: identification of the molecular determinants of color and applications in fluorescence imaging

    Directory of Open Access Journals (Sweden)

    Davidson Michael W

    2008-03-01

    mutagenesis study, we conclude that the two histidine residues in close proximity to the chromophore are approximately equal determinants of the blue-shifted fluorescence emission of mTFP1. With respect to live cell imaging applications, the mTFP1-derived mWasabi should be particularly useful in two-color imaging in conjunction with a Sapphire-type variant or as a fluorescence resonance energy transfer acceptor with a blue FP donor. In all fusions attempted, both mTFP1 and mWasabi give patterns of fluorescent localization indistinguishable from that of well-established avGFP variants.

  15. Uranium industry annual 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-05

    The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the 10-year period 1985 through 1994 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data collected on the ``Uranium Industry Annual Survey`` (UIAS) provide a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1994, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. A feature article, ``Comparison of Uranium Mill Tailings Reclamation in the United States and Canada,`` is included in the UIA 1994. Data on uranium raw materials activities including exploration activities and expenditures, EIA-estimated resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities, including purchases of uranium and enrichment services, and uranium inventories, enrichment feed deliveries (actual and projected), and unfilled market requirements are shown in Chapter 2.

  16. Uranium Provinces in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three uranium provinces are recognized in China, the Southeast China uranium province, the Northeast China-lnner Mongolia uranium province and the Northwest China (Xinjiang) uranium province. The latter two promise good potential for uranium resources and are major exploration target areas in recent years. There are two major types of uranium deposits: the Phanerozoic hydrothermal type (vein type) and the Meso-Cenozoic sandstone type in different proportions in the three uranium provinces. The most important reason or prerequisite for the formation of these uranium provinces is that Precambrian uranium-enriched old basement or its broken parts (median massifs) exists or once existed in these regions, and underwent strong tectonomagmatic activation during Phanerozoic time. Uranium was mobilized from the old basement and migrated upwards to the upper structural level together with the acidic magma originating from anatexis and the primary fluids, which were then mixed with meteoric water and resulted in the formation of Phanerozoic hydrothermal uranium deposits under extensional tectonic environments. Erosion of uraniferous rocks and pre-existing uranium deposits during the Meso-Cenozoic brought about the removal of uranium into young sedimentary basins. When those basins were uplifted and slightly deformed by later tectonic activity, roll-type uranium deposits were formed as a result of redox in permeable sandstone strata.

  17. Uranium industry annual 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-04-22

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data provides a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. The Form EIA-858 ``Uranium Industry Annual Survey`` is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs.

  18. Improved maximum entropy method for the analysis of fluorescence spectroscopy data: evaluating zero-time shift and assessing its effect on the determination of fluorescence lifetimes.

    Science.gov (United States)

    Esposito, Rosario; Mensitieri, Giuseppe; de Nicola, Sergio

    2015-12-21

    A new algorithm based on the Maximum Entropy Method (MEM) is proposed for recovering both the lifetime distribution and the zero-time shift from time-resolved fluorescence decay intensities. The developed algorithm allows the analysis of complex time decays through an iterative scheme based on entropy maximization and the Brent method to determine the minimum of the reduced chi-squared value as a function of the zero-time shift. The accuracy of this algorithm has been assessed through comparisons with simulated fluorescence decays both of multi-exponential and broad lifetime distributions for different values of the zero-time shift. The method is capable of recovering the zero-time shift with an accuracy greater than 0.2% over a time range of 2000 ps. The center and the width of the lifetime distributions are retrieved with relative discrepancies that are lower than 0.1% and 1% for the multi-exponential and continuous lifetime distributions, respectively. The MEM algorithm is experimentally validated by applying the method to fluorescence measurements of the time decays of the flavin adenine dinucleotide (FAD).

  19. A versatile chiral selector for determination of enantiomeric composition of fluorescent and nonfluorescent chiral molecules using steady-state fluorescence spectroscopy.

    Science.gov (United States)

    Williams, Alicia A; Fakayode, Sayo O; Lowry, Mark; Warner, Isiah M

    2009-02-01

    A fluorescent chiral molecular micelle (FCMM), poly (sodium N-undecanoyl-L-phenylalaninate) (poly-L-SUF), was developed as a chiral selector for enantiomeric recognition and determination of enantiomeric composition of four fluorescent and four nonfluorescent chiral molecules by use of steady-state fluorescence spectroscopy. The influence of FCMM concentration, buffer pH and complexation medium on FCMM-analyte host-guest complexation, and the emission spectral properties of the resulting complexes were investigated. The chiral interactions of the analytes,1,1'-binaphthyl-2,2'-diamine, 1-(9-anthryl)-2,2,2-trifluoroethanol, propranolol, naproxen, chloromethyl menthyl ether (CME), citramalic acid, tartaric acid, and limonene (LIM), in the presence of poly-L-SUF were based on diastereomeric complex formation. The figures of merit obtained from the partial-least-squares regression modeling of the calibration samples suggested good prediction ability for the validation of six of the eight chiral analytes. Better host-guest complexation of the more hydrophobic molecules, CME and LIM, were obtained in methanol/water mixtures, resulting in better predictability of the regression models. Prediction ability of the models was evaluated by use of the root-mean-square percent relative error (RMS%RE) and was found to range from 1.77 to 15.80% (buffer), 1.26 to 7.95% (25:75 methanol/water), and 1.21 to 4.28% (75:25 methanol/water).

  20. Determination of safranine T in food samples by CTAB sensitised fluorescence quenching method of the derivatives of calix[4]arene.

    Science.gov (United States)

    Wang, Wenjun; Zhu, Xiashi; Yan, Chaoguo

    2013-12-01

    In this paper, the interaction of safranine T (ST) and calix[4]arene (4,10,16,22-tetramethoxylresorcinarene carboxylic acid derivatives (TRCA)) was investigated with fluorescence spectroscopy. The results was shown that the fluorescence intensity of TRCA could be quenched by ST, and the fluorescence quenching (ΔF=FTRCA-FST-TRCA) was sensitised in cetyltrimethyl ammonium bromide (CTAB). Under the optimal conditions, the linear range of calibration curve for the determination of ST was 0.10-4.00 μg/mL. The detection limit and RSD was 0.034 μg/mL, 2.30% (n=3). The quantum yield (Yu) of ST was approximately 2.0 times higher in the presence of CTAB than that in the absence of CTAB. The method has been applied for the determination of ST in food samples with satisfactory results.

  1. Enzyme-catalyzed Michael addition for the synthesis of warfarin and its determination via fluorescence quenching of L-tryptophan

    Science.gov (United States)

    Yuan, Yusheng; Yang, Liu; Liu, Shaopu; Yang, Jidong; Zhang, Hui; Yan, Jingjing; Hu, Xiaoli

    2017-04-01

    A sensitive fluorescence sensor for warfarin was proposed via quenching the fluorescence of L-tryptophan due to the interaction between warfarin and L-tryptophan. Warfarin, as one of the most effective anticoagulants, was designed and synthesized via lipase from porcine pancreas (PPL) as a biocatalyst to catalyze the Michael addition of 4-hydroxycoumarin to α, β-unsaturated enones in organic medium in the presence of water. Furthermore, the spectrofluorometry was used to detect the concentration of warfarin with a linear range and detection limit (3σ/k) of 0.04-12.0 μmol L- 1 (R2 = 0.994) and 0.01 μmol L- 1, respectively. Herein, this was the first application of bio-catalytic synthesis and fluorescence for the determination of warfarin. The proposed method was applied to determine warfarin of the drug in tablets with satisfactory results.

  2. Spectrofluorometric determination of trace amounts of coenzyme II using norfioxacin-terbium complex as a fluorescent probe.

    Science.gov (United States)

    Wang, Yusheng; Liu, Jinkai; Jiang, Chongqiu

    2005-06-01

    When terbium ion (Tb3+)-norfloxacin (NFLX) complex is issued a fluorescent probe, in a buffer solution of pH = 7.6, NADP can remarkably enhance the fluorescence intensity of the Tb3+ -NFLX complex at lambda = 545 nm. The enhanced fluorescence intensity of Tb3+ is in proportion to the concentration of NADP. The dynamic range for the determination of NADP is 1.11 x 10(-7) - 6.16 x 10(-5) mol l(-1), with a detection limit of 4.31 x 10(-8) mol l(-1). This method is simple, practical and relatively free of interference from coexisting substances, so it can be successfully applied to determination of NADP in synthetic water samples.

  3. Reversed-phase liquid chromatography using mandelic acid as an eluent for the determination of uranium in presence of large amounts of thorium.

    Science.gov (United States)

    Jaison, P G; Telmore, Vijay M; Kumar, Pranaw; Aggarwal, Suresh K

    2009-02-27

    Studies were carried out for the separation of uranium (U) and thorium (Th) on reversed-phase (RP) C18 columns using mandelic acid as an eluent. Retention of thorium-mandelate on the unmodified stationary phase was found to be greater than that of uranyl-mandelate under the pH conditions employed. Th retention capacity of the stationary phase was determined as a function of pH and MeOH content of the mobile phase. The optimised parameters allowing U elution prior to Th were utilized for the determination of small amounts of U in the presence of large amounts of Th. The method has been used for the determination of U in synthetic samples with Th/U amount ratios up to 100,000 (10 microg/g of U) without any pre-separation, employing a particulate C18 column. Effect of concentration of ion interaction reagents (IIRs) on the retention was studied to understand the mechanism of adsorption of their mandelate complexes onto the stationary phase. The experiments conducted unequivocally prove that thorium-mandelate complex is neutral whereas uranyl-mandelate complex is anionic in nature.

  4. Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

    Directory of Open Access Journals (Sweden)

    M. Z. Bieroza

    2009-12-01

    Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies.

    The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

  5. Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

    Directory of Open Access Journals (Sweden)

    M. Z. Bieroza

    2010-04-01

    Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies. The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

  6. High performance liquid chromatography--atomic fluorescence spectrometric determination of arsenic species in beer samples

    Energy Technology Data Exchange (ETDEWEB)

    Melo Coelho, N.M.; Parrilla, Carmen; Cervera, M.L.; Pastor, A.; Guardia, M. de la

    2003-04-10

    A method has been developed for the direct determination of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As(V) in beers by hydride generation--atomic fluorescence spectrometry after separation of arsenic species by high performance liquid chromatography. Compounds were separated by anion-exchange chromatography with isocratic elution using KH{sub 2}PO{sub 4}/K{sub 2}HPO{sub 4} as mobile phase with elution times of 1.67, 2.08, 6.52 and 10.72 min for As(III), DMA, MMA and As(V), respectively. Parameters affecting the hydride generation of all arsenic species were studied and the best conditions were established as a reaction coil of 150 cm, for a sample injected volume of 100 {mu}l, a 4.0% (m/v) solution of sodium tetrahydroborate and 2.0 mol l{sup -1} hydrochloric acid with flow rates of 2.7 and 1.7 ml min{sup -1}, respectively and a flow rate of 500 ml min{sup -1} for the argon carrier gas. Under the best experimental conditions, the detection limit was found to be 0.12, 0.20, 0.27 and 0.39 {mu}g l{sup -1} for As(III), DMA, MMA and As(V), respectively. The relative standard deviation for eight independent determinations varied from 3.9 till 8.9% for species considered at a concentration level of 10.0 {mu}g l{sup -1}. Recovery and comparative studies evidenced that the method is suitable for the accurate determination of arsenic species in water and beer samples.

  7. Determination of flavonoids in pharmaceutical preparations using Terbium sensitized fluorescence method

    Directory of Open Access Journals (Sweden)

    M Shaghaghi

    2009-12-01

    Full Text Available "nBackground and the Purpose of the Study: The aim of this study was development and validation of a simple, rapid and sensitive spectrofluorimetric method for determination of total flavonoids in two topical formulations of Calendula officinalis, Ziziphus Spina-christi and an oral drop of Hypiran perforatum L. The proposed method is based on the formation of terbium (Tb3+ "n-flavonoids (quercetin as a reference standard complex at pH 7.0, which has fluorescence intensely with maximum emission at 545 nm when excited at 310 nm. "nMethod "n: For ointments masses of topical formulations were weighed and added to ethanol-aqueous buffer (pH 10.0 and the resulting mixtures were shaken and then two phases were separated by centrifugation. Aqueous phases were filtered and then diluted with water. For Hypiran drops an appropriate portion was diluted with ethanol and then aliquots of sample or standard solutions were determined according to the experimental procedure. "nResults "n: Under the optimum conditions, total concentrations of flavonoids (as quercetin equivalent in three tested formulations were found to be 0.204 mg/g (for Dermatin cream, 0.476 mg/g (for Calendula ointment and 13.50 μg/ml (for Hypiran drops. Analytical recoveries from samples spiked with different amounts of quercetin were 96.1-104.0 % with RSD % of less than 3.5. Conclusion : The proposed method which requires a simple dissolution step without any matrix interferences provided high sensitivity and selectivity and was easily applied to determine total flavonoids in real samples of three investigated formulations with excellent reproducibility.

  8. URANIUM RECOVERY PROCESS

    Science.gov (United States)

    Bailes, R.H.; Long, R.S.; Olson, R.S.; Kerlinger, H.O.

    1959-02-10

    A method is described for recovering uranium values from uranium bearing phosphate solutions such as are encountered in the manufacture of phosphate fertilizers. The solution is first treated with a reducing agent to obtain all the uranium in the tetravalent state. Following this reduction, the solution is treated to co-precipitate the rcduced uranium as a fluoride, together with other insoluble fluorides, thereby accomplishing a substantially complete recovery of even trace amounts of uranium from the phosphate solution. This precipitate usually takes the form of a complex fluoride precipitate, and after appropriate pre-treatment, the uranium fluorides are leached from this precipitate and rccovered from the leach solution.

  9. Simple and sensitive synchronous- fluorescence method for the determination of trace bisphenol S based on its inhibitory effect on the fluorescence quenching reaction of rhodamine B.

    Science.gov (United States)

    Cao, Gui-ping; Chen, Ting; Zhuang, Ya-feng

    2013-07-01

    An inhibitory kinetic fluorimetric method is reported for the determination of trace bisphenol S (BPS). The proposed method is based on the inhibitory effect of BPS on the fluorescence quenching of rhodamine B (RhB) caused by potassium bromate in a dilute phosphoric acid medium. Under the optimal conditions of the experiment, the detection limit for BPS was 0.021 mg/L, and the linear range of determination was from 0.035 mg/L to 0.750 mg/L. The relative standard deviations of 11 measurements for 0.20 mg/L and 0.40 mg/L BPS solutions were 2.74 % and 1.87 %, respectively. The method was successfully applied to the determination of bisphenol S derived from commercially available plastic film samples in hot water. A possible reaction mechanism of the inhibitory effect of BPS on the fluorescence quenching of RhB was proposed.

  10. Association of a novel preribosomal complex in Trypanosoma brucei determined by fluorescence resonance energy transfer.

    Science.gov (United States)

    Wang, Lei; Ciganda, Martin; Williams, Noreen

    2013-02-01

    We have previously reported that the trypanosome-specific proteins P34 and P37 form a unique preribosomal complex with ribosomal protein L5 and 5S rRNA in the nucleoplasm. We hypothesize that this novel trimolecular complex is necessary for stabilizing 5S rRNA in Trypanosoma brucei and is essential for the survival of the parasite. In vitro quantitative analysis of the association between the proteins L5 and P34 is fundamental to our understanding of this novel complex and thus our ability to exploit its unique characteristics. Here we used in vitro fluorescence resonance energy transfer (FRET) to analyze the association between L5 and P34. First, we demonstrated that FRET can be used to confirm the association between L5 and P34. We then determined that the binding constant for L5 and P34 is 0.60 ± 0.03 μM, which is in the range of protein-protein binding constants for RNA binding proteins. In addition, we used FRET to identify the critical regions of L5 and P34 involved in the protein-protein association. We found that the N-terminal APK-rich domain and RNA recognition motif (RRM) of P34 and the L18 domain of L5 are important for the association of the two proteins with each other. These results provide us with the framework for the discovery of ways to disrupt this essential complex.

  11. Phospholipid diffusion coefficients of cushioned model membranes determined via z-scan fluorescence correlation spectroscopy.

    Science.gov (United States)

    Sterling, Sarah M; Allgeyer, Edward S; Fick, Jörg; Prudovsky, Igor; Mason, Michael D; Neivandt, David J

    2013-06-25

    Model cellular membranes enable the study of biological processes in a controlled environment and reduce the traditional challenges associated with live or fixed cell studies. However, model membrane systems based on the air/water or oil/solution interface do not allow for incorporation of transmembrane proteins or for the study of protein transport mechanisms. Conversely, a phospholipid bilayer deposited via the Langmuir-Blodgett/Langmuir-Schaefer method on a hydrogel layer is potentially an effective mimic of the cross section of a biological membrane and facilitates both protein incorporation and transport studies. Prior to application, however, such membranes must be fully characterized, particularly with respect to the phospholipid bilayer phase transition temperature. Here we present a detailed characterization of the phase transition temperature of the inner and outer leaflets of a chitosan supported model membrane system. Specifically, the lateral diffusion coefficient of each individual leaflet has been determined as a function of temperature. Measurements were performed utilizing z-scan fluorescence correlation spectroscopy (FCS), a technique that yields calibration-free diffusion information. Analysis via the method of Wawrezinieck and co-workers revealed that phospholipid diffusion changes from raftlike to free diffusion as the temperature is increased-an insight into the dynamic behavior of hydrogel supported membranes not previously reported.

  12. Determination of bromine in regulated foods with a field-portable X-ray fluorescence analyzer.

    Science.gov (United States)

    Anderson, David L

    2009-01-01

    A field-portable X-ray fluorescence analyzer, factory-calibrated for soil analysis, was used to measure bromine (Br) mass fractions in reference materials, flour, bakery products, malted barley, selected U.S. Food and Drug Administration Total Diet Study foods, and other food products. By using a calibration based on instrumental neutron activation analysis results for Br in reference materials, accurate quantitative results, confirmed by z-scores, could be obtained for mass fractions of about 2-55 mg/kg. These results confirmed accuracy of results (with larger uncertainties) obtained by applying a simple correction factor to the analyzer's output value. Results showed that very short analysis times (content at regulatory levels for brominated and enriched brominated flour (24 mg/kg Br) and whole wheat flour and bakery products (36 mg/kg Br). Feasibility for determination of Br in malted barley at the regulatory level (75 mg/kg Br) was demonstrated, but quantitative results at that level could not be assured because no reference material with a suitable mass fraction was available. Br mass fractions for all foods tested were well below regulatory levels.

  13. A fast and environmental friendly analytical procedure for determination of melamine in milk exploiting fluorescence quenching.

    Science.gov (United States)

    Nascimento, Carina F; Rocha, Diogo L; Rocha, Fábio R P

    2015-02-15

    An environmental friendly procedure was developed for fast melamine determination as an adulterant of protein content in milk. Triton X-114 was used for sample clean-up and as a fluorophore, whose fluorescence was quenched by the analyte. A linear response was observed from 1.0 to 6.0mgL(-1) melamine, described by the Stern-Volmer equation I°/I=(0.999±0.002)+(0.0165±0.004) CMEL (r=0.999). The detection limit was estimated at 0.8mgL(-1) (95% confidence level), which allows detecting as low as 320μg melamine in 100g of milk. Coefficients of variation (n=8) were estimated at 0.4% and 1.4% with and without melamine, respectively. Recoveries to melamine spiked to milk samples from 95% to 101% and similar slopes of calibration graphs obtained with and without milk indicated the absence of matrix effects. Results for different milk samples agreed with those obtained by high performance liquid chromatography at the 95% confidence level.

  14. Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Maria Jose da [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Paim, Ana Paula S. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Pimentel, Maria Fernanda [Departamento de Engenharia Quimica, Universidade Federal de Pernambuco, Recife, PE (Brazil); Cervera, M. Luisa, E-mail: m.luisa.cervera@uv.es [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Guardia, Miguel de la [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain)

    2010-05-14

    A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g{sup -1} concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO{sub 3} and H{sub 2}O{sub 2} followed by dilution with water containing KBr/KBrO{sub 3} and hydroxylamine and reduction with SnCl{sub 2} in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g{sup -1} with a recovery percentage of 95 {+-} 4% at an added concentration of 5 ng g{sup -1}. The concentration level of Hg found in 24 natural rice samples from different origin ranged between 1.3 and 7.8 ng g{sup -1}.

  15. Sensitive determination of ranitidine in rabbit plasma by HPLC with fluorescence detection.

    Science.gov (United States)

    Khedr, Alaa

    2008-02-01

    A sensitive high-performance liquid chromatographic method for determination of ranitidine (RAN) in rabbit plasma is described. The method is based on liquid-liquid extraction, labeling with dansyl chloride and monitoring with fluorescence detector at 338nm (ex)/523nm (em). Plasma samples were extracted with diethyl ether alkalinized with 1M sodium hydroxide. Ephedrine HCl (EPH-HCl) was used as internal standard. Both, RAN and EPH were completely derivatized after heating at 60 degrees C for 10min in sodium bicarbonate solution (pH 9.5). The derivatized samples were analyzed by HPLC using Agilent Zorbax Extended C18 column (150mmx4.6mm i.d.) and mobile phase consists of 48% acetonitrile and 52% sodium acetate solution (0.02M, pH 4.6). The linearity of the method was in the range of 0.025-10microg/ml. The limits of detection (LOD) and quantification (LOQ) were 7.5+/-0.18 and 22.5+/-0.12ng/ml, respectively. Ranitidine recovery was 97.5+/-1.1% (n=6; R.S.D.=1.8%). The method was applied on plasma collected from rabbits at different time intervals after oral administration of 5mg/kg ranitidine HCl.

  16. Green direct determination of mineral elements in artichokes by infrared spectroscopy and X-ray fluorescence.

    Science.gov (United States)

    Mir-Marqués, Alba; Martínez-García, Maria; Garrigues, Salvador; Cervera, M Luisa; de la Guardia, Miguel

    2016-04-01

    Near infrared (NIR) and X-ray fluorescence (XRF) spectroscopy were investigated to predict the concentration of calcium, potassium, iron, magnesium, manganese and zinc in artichoke samples. Sixty artichokes were purchased from different Spanish areas (Benicarló, Valencia and Murcia). NIR and XRF spectra, combined with partial least squares (PLS) data treatment, were used to develop chemometric models for the prediction of mineral concentration. To obtain reference data, samples were mineralised and analysed by inductively coupled plasma optical emission spectrometry (ICP-OES). Coefficients of determination obtained for the regression between predicted values and reference ones for calcium, potassium, magnesium, iron, manganese and zinc were 0.61, 0.79, 0.53, 0.77, 0.54 and 0.60 for NIR and 0.96, 0.93, 0.80, 0.79, 0.76 and 0.90 for XRF, respectively. Both assayed methodologies, offer green alternatives to classical mineral analysis, but XRF provided the best results in order to be used as a quantitative screening method.

  17. Multiresidue determination of quinolone antibacterials in eggs of laying hens by liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Hassouan, M K; Ballesteros, O; Taoufiki, J; Vílchez, J L; Cabrera-Aguilera, M; Navalón, A

    2007-06-01

    An analytical method for the simultaneous determination of seven quinolones (ciprofloxacin, enrofloxacin, danofloxacin, difloxacin, flumequine, oxolinic acid and sarafloxacin) in egg samples of laying hens was developed. Their use is totally prohibited in animals from which eggs are produced for human consumption. Protein precipitation was achieved by addition of acetonitrile and ammonia, removal of acetonitrile with dichloromethane, the quinolones remaining in the basic aqueous extract. The aqueous extract was analysed by liquid chromatography with fluorescence detection (LC-FD). The mobile phase was composed of acetonitrile and 10 mM citrate buffer solution of pH 4.5, with an initial composition of acetonitrile-water (12:88, v/v) and using linear gradient elution. Norfloxacin was used as an internal standard. The limits of detection found were 4-12 ng g(-1). These values were lower than the maximum residue limits (MRLs) established by the European Union for these compounds in different tissues of eggs-producing animals.

  18. Determination of memantine in plasma and vitreous humour by HPLC with precolumn derivatization and fluorescence detection.

    Science.gov (United States)

    Puente, Belen; Hernandez, Esther; Perez, Susana; Pablo, Luis; Prieto, Esther; Garcia, Maria Angeles; Bregante, Miguel Angel

    2011-01-01

    A new HPLC procedure with precolumn derivatization and rimantadine as the internal standard for determining memantine, a candidate agent for the treatment of glaucoma in plasma and vitreous humour, has been developed and validated. Precolumn derivatization was performed with 9-fluorenylmethyl-chloroformate-chloride (FMOC-Cl) as the derivatization reagent and followed by a liquid-liquid extraction with n-hexane. Optimal conditions for derivatization were an FMOC-Cl concentration of 1.5 mM, a reaction time of 20 min, the temperature at 30°C, the borate buffer pH 8.5, and a borate buffer-acetonitrile ratio of 1:1. The derivatives were analyzed by isocratic HPLC with the fluorescence detector λex 260 nm λem 315 nm on a Novapack C(18) reversed-phase column with a mobile phase of acetonitrile-water (73:27, v/v), 40°C, and a flow rate of 1.2 mL/min. The linear range was 10-1000 ng/mL with a quantification limit of ∼ 10 ng/mL for both types of samples. This analytical method may be suitable for using in ocular availability studies.

  19. Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

    Energy Technology Data Exchange (ETDEWEB)

    Nardes, Raysa C.; Santos, Ramon S.; Sanches, Francis A.C.R.A.; Gama Filho, Hamilton S.; Oliveira, Davi F.; Anjos, Marcelino J., E-mail: rc.nardes@gmail.com, E-mail: ramonziosp@yahoo.com.br, E-mail: francissanches@gmail.com, E-mail: hamiltongamafilho@hotmail.com, E-mail: davi.oliveira@uerj.br, E-mail: marcelin@uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Instituto de Fisica. Departamento de Fisica Aplicada e Termodinamica

    2015-07-01

    Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

  20. Determination of the modulation transfer function for a time-gated fluorescence imaging system.

    Science.gov (United States)

    Gundy, Sarah; Van der Putten, Wil; Shearer, Andy; Buckton, Daniel; Ryder, Alan G

    2004-01-01

    The use of fluorescence for cancer detection is currently under investigation. Presently, steady-state fluorescence detection methods are in use, but have limitations due to poor contrast between the fluorescence of the tumor and background autofluorescence. Improved contrast can be obtained with time-resolved techniques because of the differing lifetimes between autofluorescence and exogenous photosensitizers that selectively accumulate within tumor tissue. An imaging system is constructed using a fast-gated (200-ps) charge-coupled device (CCD) camera and a pulsed 635-nm laser diode. To characterize the ability of the system to transfer object contrast to an image, the modulation transfer function (MTF) of the system is acquired by employing an extended knife-edge technique. A knife-edge target is assembled by drilling a rectangular well into a block of polymethyl methacrylate (PMMA). The imaging system records images of the photosensitizer, chloroaluminum phthalocyanine tetrasulfonate (AlPcTS), within the well. AlPcTS was chosen to test the system because of its strong absorption of 635-nm, high fluorescence yield, and relatively long fluorescence lifetime (approximately 7.5 ns). The results show that the system is capable of resolving 10(-4) M AlPcTS fluorescence as small as 1 mm. The findings of this study contribute to the development of a time-gated imaging system using fluorescence lifetimes. Copyright 2004 Society of Photo-Optical Instrumentation Engineers.

  1. Study of resolution enhancement methods for impurities quantitative analysis in uranium compounds by XRF

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clayton P.; Salvador, Vera L.R.; Cotrim, Marycel E.B.; Pires, Maria Ap. F.; Scapin, Marcos A., E-mail: clayton.pereira.silva@usp.b [Instituto de Pesquisas Energeticas e Nucleares (CQMA/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2011-07-01

    X-ray fluorescence analysis is a technique widely used for the determination of both major and trace elements related to interaction between the sample and radiation, allowing direct and nondestructive analysis. However, in uranium matrices these devices are inefficient because the characteristic emission lines of elements like S, Cl, Zn, Zr, Mo and other overlap characteristic emission lines of uranium. Thus, chemical procedures to separation of uranium are needed to perform this sort of analysis. In this paper the deconvolution method was used to increase spectra resolution and correct the overlaps. The methodology was tested according to NBR ISO 17025 using a set of seven certified reference materials for impurities present in U3O8 (New Brunswick Laboratory - NBL). The results showed that this methodology allows quantitative determination of impurities such as Zn, Zr, Mo and others, in uranium compounds. The detection limits were shorter than 50{mu}g. g{sup -1} and uncertainty was shorter than 10% for the determined elements. (author)

  2. Occurrence of aflatoxins in peanuts and peanut products determined by liquid chromatography with fluorescence detection

    Directory of Open Access Journals (Sweden)

    Stojanovska-Dimzoska Biljana

    2013-01-01

    Full Text Available Liquid chromatography with fluorescence detection using immunoaffinity column clean-up was a method described for determination of aflatoxins (AFB1, AFB2, AFG1 and AFG2 in peanuts and peanut based products. The validation of the procedure was performed. Good coefficient of correlation was found for all aflatoxins in the range of 0.9993-0.9999. Limit of detection (LOD and limit of quantification (LOQ ranged from 0.003-0.005 mg/kg and 0.009-0.023 mg/kg, respectively, which was acceptable. The mean recovery for total aflatoxins was 88.21%. The method also showed acceptable precision values in the range of 0.171-2.626% at proposed concentration levels for all four aflatoxins. RSDR values (within laboratory reproducibility calculated from the results showed good correlation between two analysts for all aflatoxins and they ranged from 4.93-11.87%. The developed method was applied for the determination of aflatoxins in 27 samples of peanuts and peanut based products. The results showed that 21 peanut samples (77.7% were below LOD of the method. Three samples had positive results over the MRL. There was one extreme value recorded for the total aflatoxins in peanut (289.2 mg/kg and two peanut based products, peanut snack and peanut, with total content of aflatoxins being 16.3 mg/kg and 8.0 mg/kg, respectively. The obtained results demonstrated that the procedure was suitable for the de­termination of aflatoxins in peanuts and peanut based products and it could be implemented for the routine analysis.

  3. Automatic determination of NET (neutrophil extracellular traps) coverage in fluorescent microscopy images.

    Science.gov (United States)

    Coelho, Luis Pedro; Pato, Catarina; Friães, Ana; Neumann, Ariane; von Köckritz-Blickwede, Maren; Ramirez, Mário; Carriço, João André

    2015-07-15

    Neutrophil extracellular traps (NETs) are believed to be essential in controlling several bacterial pathogens. Quantification of NETs in vitro is an important tool in studies aiming to clarify the biological and chemical factors contributing to NET production, stabilization and degradation. This estimation can be performed on the basis of fluorescent microscopy images using appropriate labelings. In this context, it is desirable to automate the analysis to eliminate both the tedious process of manual annotation and possible operator-specific biases. We propose a framework for the automated determination of NET content, based on visually annotated images which are used to train a supervised machine-learning method. We derive several methods in this framework. The best results are obtained by combining these into a single prediction. The overall Q(2) of the combined method is 93%. By having two experts label part of the image set, we were able to compare the performance of the algorithms to the human interoperator variability. We find that the two operators exhibited a very high correlation on their overall assessment of the NET coverage area in the images (R(2) is 97%), although there were consistent differences in labeling at pixel level (Q(2), which unlike R(2) does not correct for additive and multiplicative biases, was only 89%). Open source software (under the MIT license) is available at https://github.com/luispedro/Coelho2015_NetsDetermination for both reproducibility and application to new data. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. Depth determination of the subsurface uranium deposits using CR-39 cylindrical technique in Gneissoic granitic rocks, Abu Rushied area, Southeastern Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Sayed F. Hassan

    2015-10-01

    Full Text Available Using solid state nuclear track detectors and employing CR-39 cylindrical technique, the depth of the subsurface uranium deposits were determined. This techniques depends mainly on the nuclear track detector situated in zigzag form inside a polyethylene cylinder of 65 cm length and 7 cm diameter. This technique was applied on a borehole in a granite mass Abu Rushied area, southeast area desert. The obtained results revealed that, the depth of U -ore deposited reached about 89 m with thickness nearly 24 m. The obtained data for radon concentrations were also used for the determination of the exhalation rates, the measured values for exhalation rate (mBqm−2h−1 varies between 6.14E-03 at h = 50 cm and 4.53E-02 at h = 10 cm, The obtained values are comparable with that recorded for the granite type of rock.

  5. Determination of the PSI/PSII ratio in living plant cells at room temperature by spectrally resolved fluorescence spectroscopy

    Science.gov (United States)

    Elgass, Kirstin; Zell, Martina; Maurino, Veronica G.; Schleifenbaum, Frank

    2011-02-01

    Leaf cells of living plants exhibit strong fluorescence from chloroplasts, the reaction centers of photosynthesis. Mutations in the photosystems change their structure and can, thus, be monitored by recording the fluorescence spectra of the emitted chlorophyll light. These measurements have, up to now, mostly been carried out at low temperatures (77 K), as these conditions enable the differentiation between the fluorescence of Photosystem I (PSI) and Photosystem II (PSII). In contrast, at room temperature, energy transfer processes between the various photosynthetic complexes result in very similar fluorescence emissions, which mainly consist of fluorescence photons emitted by PSII hindering a discrimination based on spectral ROIs (regions of interest). However, by statistical analysis of high resolution fluorescence spectra recorded at room temperature, it is possible to draw conclusions about the relative PSI/PSII ratio. Here, the possibility of determining the relative PSI/PSII ratio by fluorescence spectroscopy is demonstrated in living maize plants. Bundle-sheath chloroplasts of mature maize plants have a special morphologic characteristic; they are agranal, or exhibit only rudimentary grana, respectively. These chloroplasts are depleted in PSII activity and it could be shown that PSII is progressively reduced during leaf differentiation. A direct comparison of PSII activity in isolated chloroplasts is nearly impossible, since the activity of PSII in both mesophyll- and bundle-sheath chloroplasts decays with time after isolation and it takes significantly longer to isolate bundle-sheath chloroplasts. Considering this fact the measurement of PSI/PSII ratios with the 77K method, which includes taking fluorescence spectra from a diluted suspension of isolated chloroplasts at 77K, is questionable. These spectra are then used to analyze the distribution of energy between PSI and PSII. After rapid cooling to 77K secondary biochemical influences, which attenuate the

  6. Polyacrylamide hydrogel encapsulated E. coli expressing metal-sensing green fluorescent protein as a potential tool for copper ion determination.

    Science.gov (United States)

    Tantimongcolwat, Tanawut; Isarankura-Na-Ayudhya, Chartchalerm; Srisarin, Apapan; Galla, Hans-Joachim; Prachayasittikul, Virapong

    2014-01-01

    A simple, inexpensive and field applicable metal determination system would be a powerful tool for the efficient control of metal ion contamination in various sources e.g. drinking-water, water reservoir and waste discharges. In this study, we developed a cell-based metal sensor for specific and real-time detection of copper ions. E. coli expressing metal-sensing green fluorescent protein (designated as TG1/(CG)6GFP and TG1/H6CdBP4GFP) were constructed and served as a metal analytical system. Copper ions were found to exert a fluorescence quenching effect, while zinc and cadmium ions caused minor fluorescence enhancement in the engineered bacterial suspension. To construct a user-friendly and reagentless metal detection system, TG1/H6CdBP4GFP and TG1/(CG)6GFP were encapsulated in polyacrylamide hydrogels that were subsequently immobilized on an optical fiber equipped with a fluorescence detection module. The sensor could be applied to measure metal ions by simply dipping the encapsulated bacteria into a metal solution and monitoring fluorescence changes in real time as a function of the metal concentration in solution. The sensor system demonstrated high specificity toward copper ions. The fluorescence intensities of the encapsulated TG1/(CG)6GFP and TG1/H6CdBP4GFP were quenched by approximately 70 % and 80 % by a high-dose of copper ions (50 mM), respectively. The level of fluorescence quenching exhibited a direct correlation with the copper concentration, with a linear correlation coefficient (r) of 0.99. The cell-based metal sensor was able to efficiently monitor copper concentrations ranging between 5 M and 50 mM, encompassing the maximum allowed copper contamination in drinking water (31.15 M) established by the WHO. Furthermore, the cell-based metal sensor could undergo prolonged storage for at least 2 weeks without significantly influencing the copper sensitivity.

  7. Far-red fluorescence gene reporter tomography for determination of placement and viability of cell-based gene therapies.

    Science.gov (United States)

    Lu, Yujie; Darne, Chinmay D; Tan, I-Chih; Zhu, Banghe; Hall, Mary A; Lazard, Zawaunyka W; Davis, Alan R; Simpson, Lashan; Sevick-Muraca, Eva M; Olmsted-Davis, Elizabeth A

    2013-10-01

    Non-invasive injectable cellular therapeutic strategies based on sustained delivery of physiological levels of BMP-2 for spinal fusion are emerging as promising alternatives, which could provide sufficient fusion without the associated surgical risks. However, these injectable therapies are dependent on bone formation occurring only at the specific target region. In this study, we developed and deployed fluorescence gene reporter tomography (FGRT) to provide information on in vivo cell localization and viability. This information is sought to confirm the ideal placement of the materials with respect to the area where early bone reaction is required, ultimately providing three dimensional data about the future fusion. However, because almost all conventional fluorescence gene reporters require visible excitation wavelengths, current in vivo imaging of fluorescent proteins is limited by high tissue absorption and confounding autofluorescence. We previously administered fibroblasts engineered to produce BMP-2, but is difficult to determine 3-D information of placement prior to bone formation. Herein we used the far-red fluorescence gene reporter, IFP1.4 to report the position and viability of fibroblasts and developed 3-D tomography to provide placement information. A custom small animal, far-red fluorescence tomography system integrated into a commercial CT scanner was used to assess IFP1.4 fluorescence and to demark 3-D placement of encapsulated fibroblasts with respect to the vertebrae and early bone formation as assessed from CT. The results from three experiments showed that the placement of the materials within the spine could be detected. This work shows that in vivo fluorescence gene reporter tomography of cell-based gene therapy is feasible and could help guide cell-based therapies in preclinical models.

  8. Use of the Protease Fluorescent Detection Kit to Determine Protease Activity

    OpenAIRE

    Cupp-Enyard, Carrie

    2009-01-01

    The Protease Fluorescent Detection Kit provides ready-to-use reagents for detecting the presence of protease activity. This simple assay to detect protease activity uses casein labeled with fluorescein isothiocyanate (FITC) as the substrate.

  9. Simultaneous determination of 11 fluorescent whitening agents in food-contact paper and board by ion-pairing high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Jiang, Dingguo; Chen, Lisong; Fu, Wusheng; Qiu, Hanquan

    2015-02-01

    4,4'-Diaminostilbene-2,2'-disulfonic acid based fluorescent whitening agents (DSD-FWAs) are prohibited in food-contact paper and board in many countries. In this work, a reliable high-performance liquid chromatography method was developed for the simultaneous determination of 11 common DSD-FWAs in paper material. Sample preparation and extraction as well as chromatographic separation of multicomponent DSD-FWAs were successfully optimized. DSD-FWAs in prepared samples were ultrasonically extracted with acetonitrile/water/triethylamine (40:60:1, v/v/v), separated on the C(18) column with the mobile phase containing tetrabutylammonium bromide, and then detected by a fluorescence detector. The limits of detection were 0.12-0.24 mg/kg, and the calibration curves showed the linear correlation (R(2) ≥ 0.9994) within the range of 8.0-100 ng/mL, which was equivalent to the range of 0.80-10 mg/kg in the sample. The average recoveries and the RSDs were 81-106% and 2-9% at two fortification levels (1.0 and 5.0 mg/kg) in paper bowls, respectively. The successful determination of 11 DSD-FWAs in food-contact paper and board obtained from local markets indicated that the newly developed method was rapid, accurate, and highly selective.

  10. Cathodoluminescence of uranium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Winer, K.; Colmenares, C.; Wooten, F.

    1984-08-09

    The cathodoluminescence of uranium oxide surfaces prepared in-situ from clean uranium exposed to dry oxygen was studied. The broad asymmetric peak observed at 470 nm is attributed to F-center excitation.

  11. Uranium Processing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — An integral part of Y‑12's transformation efforts and a key component of the National Nuclear Security Administration's Uranium Center of Excellence, the Uranium...

  12. A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate and oxyhydroxide minerals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.; Zachara, J.M.; Liu, C.; Gassman, P.L.; Felmy, A.R. [Pacific Northwest National Lab., Richland, WA (United States); Clark, S.B. [Washington State Univ., Pullman, WA (United States)

    2008-07-01

    In this work we applied time-resolved laser-induced fluorescence spectroscopy (TRLIF) at both room temperature (RT) and near liquid-helium temperature (6 K) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, becquerelite, schoepite, meta-schoepite, dehydrated schoepite and compreignacite, and have compared the spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra of rutherfordine showed significant difference from those of zellerite and liebigite. The fluorescence spectra of the phosphate minerals closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared to those of the uranium carbonates and phosphates and their vibronic bands are broad and less resolved at RT. The enhanced spectra resolution at 6 K allows more accurate determination of the fluorescence band origin and offers a complemental method to measure the O=U=O symmetrical stretch frequency, {nu}{sub 1}, from the spacings of the vibronic bands of the fluorescence spectra. The average {nu}{sub 1} values appear to be inversely correlated with the average pK{sub a} values of the anions. (orig.)

  13. Determination of roxithromycin in human plasma by HPLC with fluorescence and UV absorbance detection: application to a pharmacokinetic study.

    Science.gov (United States)

    Główka, Franciszek K; Karaźniewicz-Łada, Marta

    2007-06-01

    A selective HPLC method with fluorescence detection for the determination of roxithromycin (ROX) in human plasma was described. After solid-phase extraction (SPE), ROX and erythromycin (internal standard, I.S.) were derivatized by treatment with 9-fluorenylmethyl chloroformate (FMOC-Cl). Optimal resolution of fluorescence derivatives of ROX and I.S. was obtained during one analytical run using reversed phase, C(18) column. The mobile phase was composed of potassium dihydrogenphosphate solution, pH 7.5 and acetonitrile. Fluorescence of the compounds was measured at the maximum excitation, 255 nm and emission, 313 nm, of ROX derivatives. Validation parameters of the method were also established. After SPE, differences in recoveries of ROX and erythromycin from human plasma were observed. The linear range of the standard curve of ROX in plasma was 0.5-10.0 mg/l. The validated method was successfully applied for pharmacokinetic studies of ROX after administration of a single tablet of ROX.

  14. Determination of inorganic compounds in drinking water on the basis of house water heater scale, part 1: Determination of heavy metals and uranium

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2004-01-01

    Full Text Available The analysis of scale originated from drinking water on the house water heater, showed that scale is basically calcium carbonate that crystallizes hexagonally in the form of calcite. Scale taken as a sample from different spots in Belgrade – upper town of Zemun (sample 1 and Pančevo (sample 2 showed different configuration although it came from the same waterworks. That indicates either that the water flowing through waterworks pipes in different parts of the city is not the same or the waterworks net is not the same (age, maintaining, etc. All the elements which are dominant in drinking water (Ca, Mg, K, and Na, and which could be found in water by natural processes, are by their content far below the values regulated by law. The analysis also showed the presence of many metals: Ti, Pb, Zn, Cu Li, Sr, Cd, and Cr in the first sample, which are not found in the scale taken near Pančevo. The results obtained by calculating the mass concentration in drinking water on the basis of scale content, showed that both waters belonged to the category of low mineral waters. Contents of inorganic substances in these waters (117.85 mg/dm3 for sample 1 or 80.83 mg/dm3 for sample 2 are twice lower than the values predicted by the legislation. Gammaspectrometric analysis indicates the presence of radioactive elements – uranium and strontium which can influence human health.

  15. Uranium industry annual 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The Uranium Industry Annual 1995 (UIA 1995) provides current statistical data on the U.S. uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1995 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the period 1986 through 2005 as collected on the Form EIA-858, ``Uranium Industry Annual Survey``. Data collected on the ``Uranium Industry Annual Survey`` provide a comprehensive statistical characterization of the industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1995, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. Data on uranium raw materials activities for 1986 through 1995 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2005, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. The methodology used in the 1995 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. For the reader`s convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix D along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 14 figs., 56 tabs.

  16. Total reflection X-ray fluorescence trace mercury determination by trapping complexation: Application in advanced oxidation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Custo, Graciela [Unidad de Actividad Quimica, Comision Nacional de Energia Atomica, Av. Gral Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina); Litter, Marta I. [Unidad de Actividad Quimica, Comision Nacional de Energia Atomica, Av. Gral Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina); Escuela de Posgrado, Universidad de General San Martin, San Lorenzo 3391 Villa Ballester, 1653. Prov. de Buenos Aires (Argentina); Rodriguez, Diana [Universidad Nacional de Lujan, Ruta 5 y 7. Prov. de Buenos Aires (Argentina); Vazquez, Cristina [Unidad de Actividad Quimica, Comision Nacional de Energia Atomica, Av. Gral Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina) and Laboratorio de Quimica de Sistemas Heterogeneos, Facultad de Ingenieria, Universidad de Buenos Aires, P. Colon 850 (C1063ACU), Buenos Aires (Argentina)]. E-mail: Cristina.Vazquez@cnea.gov.ar

    2006-11-15

    It is well known that Hg species cause high noxious effects on the health of living organisms even at very low levels (5 {mu}g/L). Quantification of this element is an analytical challenge due to the peculiar physicochemical properties of all Hg species. The regulation of the maximal allowable Hg concentration led to search for sensitive methods for its determination. Total reflection X-ray fluorescence is a proved instrumental analytical tool for the determination of trace elements. In this work, the use of total reflection X-ray fluorescence for Hg quantification is investigated. However, experimental determination by total reflection X-ray fluorescence requires depositing a small volume of sample on the reflector and evaporation of the solvent until dryness to form a thin film. Because of volatilization of several Hg forms, a procedure to capture these volatile species in liquid samples by using complexing agents is proposed. Acetate, oxalic acid, ethylenediaminetetracetic acid and ammonium pyrrolidine-dithiocarbamate were assayed for trapping the analytes into the solution during the preparation of the sample and onto the reflector during total reflection X-ray fluorescence measurements. The proposed method was applied to evaluate Hg concentration during TiO{sub 2}-heterogeneous photocatalysis, one of the most known advanced oxidation technologies. Advanced oxidation technologies are processes for the treatment of effluents in waters and air that involve the generation of very active oxidative and reductive species. In heterogeneous photocatalysis, Hg is transformed to several species under ultraviolet illumination in the presence of titanium dioxide. Total reflection X-ray fluorescence was demonstrated to be applicable in following the extent of the heterogeneous photocatalysis reaction by determining non-transformed Hg in the remaining solution.

  17. Total reflection X-ray fluorescence trace mercury determination by trapping complexation: Application in advanced oxidation technologies

    Science.gov (United States)

    Custo, Graciela; Litter, Marta I.; Rodríguez, Diana; Vázquez, Cristina

    2006-11-01

    It is well known that Hg species cause high noxious effects on the health of living organisms even at very low levels (5 μg/L). Quantification of this element is an analytical challenge due to the peculiar physicochemical properties of all Hg species. The regulation of the maximal allowable Hg concentration led to search for sensitive methods for its determination. Total reflection X-ray fluorescence is a proved instrumental analytical tool for the determination of trace elements. In this work, the use of total reflection X-ray fluorescence for Hg quantification is investigated. However, experimental determination by total reflection X-ray fluorescence requires depositing a small volume of sample on the reflector and evaporation of the solvent until dryness to form a thin film. Because of volatilization of several Hg forms, a procedure to capture these volatile species in liquid samples by using complexing agents is proposed. Acetate, oxalic acid, ethylenediaminetetracetic acid and ammonium pyrrolidine-dithiocarbamate were assayed for trapping the analytes into the solution during the preparation of the sample and onto the reflector during total reflection X-ray fluorescence measurements. The proposed method was applied to evaluate Hg concentration during TiO 2-heterogeneous photocatalysis, one of the most known advanced oxidation technologies. Advanced oxidation technologies are processes for the treatment of effluents in waters and air that involve the generation of very active oxidative and reductive species. In heterogeneous photocatalysis, Hg is transformed to several species under ultraviolet illumination in the presence of titanium dioxide. Total reflection X-ray fluorescence was demonstrated to be applicable in following the extent of the heterogeneous photocatalysis reaction by determining non-transformed Hg in the remaining solution.

  18. On the interaction of uranium with the bioligands citric acid and glucose; Zur Wechselwirkung von Uran mit den Bioliganden Citronensaeure und Glucose

    Energy Technology Data Exchange (ETDEWEB)

    Steudtner, Robin

    2011-10-26

    For a better understanding of the actinide behaviour in human (in term of metabolism, retention, excretion) and in geological and biological systems, it is of prime importance to have a good knowledge of the relevant speciation. In model systems the chemical behaviour of uranium regarding complex formation and redox reaction were investigated. On this basis determinates thermodynamics constants and redox behaviour are used to prognoses a safety assessment for the respective system. The pentavalent uranium(V) is a metastable intermediate in natural redox system between uranium(IV) and uranium(VI). In this study the uranium(V) fluorescence was detected by laser spectroscopic methods ({lambda}{sub ex} = 255 nm) for the first time. The peak maxima ({lambda}{sub ex} = 255 nm) of luminescence spectrum of the photo reduced U(V) in aqueous perchlorate/2-propanol solution was detected at 440 nm and a fluorescence lifetime of 1.1 {+-} 0.02 {mu}s was calculated. The stable aqueous uranyl(V)-tricarbonate complex was characterized by fluorescence spectroscopy ({lambda}{sub ex} = 255 nm and 408 nm). The known quench effects of carbonate could be minimized by coupling the laser fluorescence system with the low temperature technique. The resulting U(V) fluorescence emission bands were detected between 375 nm and 445 nm. The peak maxima were identified at 401.5 nm ({lambda}{sub ex} = 255 nm) and 413.0 nm ({lambda}{sub ex} = 408 nm). The fluorescence lifetime of the uranyl(V)-carbonate species was determined at 153 K as 120 {+-} 0.1 {mu}s ({lambda}{sub ex} = 255 nm). In addition the fluorescence of uranium(V) was verifies by confocal laser scanning microscopy. The oxidation process from uranium(IV) to uranium(VI) was investigated on solid uraninite (UO{sub 2}) and uranium(IV) tetra chloride (UCl{sub 4}) and a 1 x 10{sup -2} M uranium(IV) sulphate (U{sup IV}SO{sub 4}) solution. By continuous oxygen transfer the uranium(IV) was oxidized slowly to uranium(VI). The temporal process was

  19. On the interaction of uranium with the bioligands citric acid and glucose; Zur Wechselwirkung von Uran mit den Bioliganden Citronensaeure und Glucose

    Energy Technology Data Exchange (ETDEWEB)

    Steudtner, Robin

    2011-10-26

    For a better understanding of the actinide behaviour in human (in term of metabolism, retention, excretion) and in geological and biological systems, it is of prime importance to have a good knowledge of the relevant speciation. In model systems the chemical behaviour of uranium regarding complex formation and redox reaction were investigated. On this basis determinates thermodynamics constants and redox behaviour are used to prognoses a safety assessment for the respective system. The pentavalent uranium(V) is a metastable intermediate in natural redox system between uranium(IV) and uranium(VI). In this study the uranium(V) fluorescence was detected by laser spectroscopic methods ({lambda}{sub ex} = 255 nm) for the first time. The peak maxima ({lambda}{sub ex} = 255 nm) of luminescence spectrum of the photo reduced U(V) in aqueous perchlorate/2-propanol solution was detected at 440 nm and a fluorescence lifetime of 1.1 {+-} 0.02 {mu}s was calculated. The stable aqueous uranyl(V)-tricarbonate complex was characterized by fluorescence spectroscopy ({lambda}{sub ex} = 255 nm and 408 nm). The known quench effects of carbonate could be minimized by coupling the laser fluorescence system with the low temperature technique. The resulting U(V) fluorescence emission bands were detected between 375 nm and 445 nm. The peak maxima were identified at 401.5 nm ({lambda}{sub ex} = 255 nm) and 413.0 nm ({lambda}{sub ex} = 408 nm). The fluorescence lifetime of the uranyl(V)-carbonate species was determined at 153 K as 120 {+-} 0.1 {mu}s ({lambda}{sub ex} = 255 nm). In addition the fluorescence of uranium(V) was verifies by confocal laser scanning microscopy. The oxidation process from uranium(IV) to uranium(VI) was investigated on solid uraninite (UO{sub 2}) and uranium(IV) tetra chloride (UCl{sub 4}) and a 1 x 10{sup -2} M uranium(IV) sulphate (U{sup IV}SO{sub 4}) solution. By continuous oxygen transfer the uranium(IV) was oxidized slowly to uranium(VI). The temporal process was

  20. Field Determination Of Ground Water Contamination Using Laser Fluorescence And Fiber Optics

    Science.gov (United States)

    Chudyk, Wayne; Pohlig, Kenneth; Wolf, Lisa; Fordiani, Rita

    1990-02-01

    Experience at over sixteen sites containing over one hundred wells has shown the feasibility of using fiber optic systems for in situ measurement of aromatic ground water contaminants. Aromatic solvents, as well as the benzene, ethylbenzene, toluene, and xylenes (BTEX) fraction of gasoline, have been detected using a prototype field instrument. Well depths have varied from 5 m to 30 m, and limits of detection at 10 m have been in the ppb range. We are routinely using two separate clear tefzel-coated optical fibers bound in a black teflon tubing for in situ sensing of aromatic organic ground water contaminants via laser-induced fluorescence. One fiber, the excitation fiber, carries the 266 nm, 15 nanosecond, laser pulse down to the sensor. The other fiber, used for detection, carries collected fluorescence plus scattered laser light back up to the surface to the detector. Optical crosstalk has been observed to occur along the entire length of the sensor tubing. This may be due to fiber fluorescence. The fiber crosstalk is eliminated by use of a 320 nm cutoff filter in the detector optics. Black tefzel-coated fibers are also commercially available which could eliminate this potential problem. Evaluation of fluorescence emission versus concentration using serial dilution of standards shows that fluorescence lifetimes are important when evaluating different concentrations as well as in evaluation of mixtures. Minimization of signal-to-noise ratios in the detector electronics involves tuning the gate width used in measuring the fluorescent pulse, in order to include the full fluorescent signal returning from the contaminants. Field tests of the modular prototype instrument have been successful in their demonstration of the feasibility of this new technology. Results at a variety of types of sites are presented, showing the flexibility of the modular approach used in the design and operation of this new instrument.

  1. Determination of traces of uranium and thorium in titanium and copper used for the construction of the Russian Emission Detector 100 by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Poteshin, Sergey S; Sysoev, Alexey A; Lagunov, Sergey S; Sereda, Andrei; Sosnovtsev, Valery V; Bolozdynya, Alexander I; Efremenko, Yuriy B

    2015-01-01

    The Russian Emission Detector 100 (RED-100) under construction at the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is designed to detect the presently undiscovered effect of coherent neutrino scattering. One of the factors limiting the sensitivity of the detector is the spontaneous decay of uranium and thorium in the detector materials. Radioactive impurities in detector materials at levels of parts per billion can significantly affect the sensitivity. Five random samples of titanium and one of copper from materials used in the construction of the detector were selected for assay. The concentration of (232)Th and (238)U were measured by inductively coupled plasma mass spectrometry (ICP- MS) in solid titanium using both: solutions in acids and direct sampling by laser ablation (LA-ICP-MS). The LA- ICP-MS method allowed us to determine (238)U and (232)Th at subnanogram per gram levels. This method is much faster than ICP-MS with liquid injection. The titanium samples studied have impurities in the range between 1 ng g(-1) and 21 ng g(-1) for (238)U and 3 ng g(-1) and 31 ng g(-1) for (232)Th. In copper we set upper limits of 0.4 ng g(-1) for (238)U and 1 ng g(-1)for (232)Th. The total activity of the cryostat constructed from materials studied was estimated to be 43 Bq.

  2. 234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples.

    Science.gov (United States)

    Godoy, Maria Luiza D P; Godoy, José Marcus; Kowsmann, Renato; Dos Santos, Guaciara M; Petinatti da Cruz, Rosana

    2006-01-01

    A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.

  3. Uptake of uranium by aquatic plants growing in fresh water ecosystem around uranium mill tailings pond at Jaduguda, India

    Energy Technology Data Exchange (ETDEWEB)

    Jha, V.N., E-mail: jhavn1971@gmail.com; Tripathi, R.M., E-mail: tripathirm@yahoo.com; Sethy, N.K., E-mail: sethybarc@rediffmail.com; Sahoo, S.K., E-mail: sksbarc@gmail.com

    2016-01-01

    Concentration of uranium was determined in aquatic plants and substrate (sediment or water) of fresh water ecosystem on and around uranium mill tailings pond at Jaduguda, India. Aquatic plant/substrate concentration ratios (CRs) of uranium were estimated for different sites on and around the uranium mill tailings disposal area. These sites include upstream and downstream side of surface water sources carrying the treated tailings effluent, a small pond inside tailings disposal area and residual water of this area. Three types of plant groups were investigated namely algae (filamentous and non-filamentous), other free floating & water submerged and sediment rooted plants. Wide variability in concentration ratio was observed for different groups of plants studied. The filamentous algae uranium concentration was significantly correlated with that of water (r = 0.86, p < 0.003). For sediment rooted plants significant correlation was found between uranium concentration in plant and the substrate (r = 0.88, p < 0.001). Both for other free floating species and sediment rooted plants, uranium concentration was significantly correlated with Mn, Fe, and Ni concentration of plants (p < 0.01). Filamentous algae, Jussiaea and Pistia owing to their high bioproductivity, biomass, uranium accumulation and concentration ratio can be useful for prospecting phytoremediation of stream carrying treated or untreated uranium mill tailings effluent. - Highlights: • Uranium mill tailings pond. • Jaduguda, India. • Fresh water plants. • Uranium uptake. • Relationship of uranium with stable elements.

  4. Evaluation and application of anion exchange resins to measure groundwater uranium flux at a former uranium mill site.

    Science.gov (United States)

    Stucker, Valerie; Ranville, James; Newman, Mark; Peacock, Aaron; Cho, Jaehyun; Hatfield, Kirk

    2011-10-15

    Laboratory tests and a field validation experiment were performed to evaluate anion exchange resins for uranium sorption and desorption in order to develop a uranium passive flux meter (PFM). The mass of uranium sorbed to the resin and corresponding masses of alcohol tracers eluted over the duration of groundwater installation are then used to determine the groundwater and uranium contaminant fluxes. Laboratory based batch experiments were performed using Purolite A500, Dowex 21K and 21K XLT, Lewatit S6328 A resins and silver impregnated activated carbon to examine uranium sorption and extraction for each material. The Dowex resins had the highest uranium sorption, followed by Lewatit, Purolite and the activated carbon. Recoveries from all ion exchange resins were in the range of 94-99% for aqueous uranium in the environmentally relevant concentration range studied (0.01-200 ppb). Due to the lower price and well-characterized tracer capacity, Lewatit S6328 A was used for field-testing of PFMs at the DOE UMTRA site in Rifle, CO. The effect on the flux measurements of extractant (nitric acid)/resin ratio, and uranium loading were investigated. Higher cumulative uranium fluxes (as seen with concentrations>1 ug U/gram resin) yielded more homogeneous resin samples versus lower cumulative fluxes (uranium. Resin homogenization and larger volume extractions yield reproducible results for all levels of uranium fluxes. Although PFM design can be improved to measure flux and groundwater flow direction, the current methodology can be applied to uranium transport studies.

  5. Antibiotic transport in resistant bacteria: synchrotron UV fluorescence microscopy to determine antibiotic accumulation with single cell resolution.

    Directory of Open Access Journals (Sweden)

    Slávka Kaščáková

    Full Text Available A molecular definition of the mechanism conferring bacterial multidrug resistance is clinically crucial and today methods for quantitative determination of the uptake of antimicrobial agents with single cell resolution are missing. Using the naturally occurring fluorescence of antibacterial agents after deep ultraviolet (DUV excitation, we developed a method to non-invasively monitor the quinolones uptake in single bacteria. Our approach is based on a DUV fluorescence microscope coupled to a synchrotron beamline providing tuneable excitation from 200 to 600 nm. A full spectrum was acquired at each pixel of the image, to study the DUV excited fluorescence emitted from quinolones within single bacteria. Measuring spectra allowed us to separate the antibiotic fluorescence from the autofluorescence contribution. By performing spectroscopic analysis, the quantification of the antibiotic signal was possible. To our knowledge, this is the first time that the intracellular accumulation of a clinical antibiotic could be determined and discussed in relation with the level of drug susceptibility for a multiresistant strain. This method is especially important to follow the behavior of quinolone molecules at individual cell level, to quantify the intracellular concentration of the antibiotic and develop new strategies to combat the dissemination of MDR-bacteria. In addition, this original approach also indicates the heterogeneity of bacterial population when the same strain is under environmental stress like antibiotic attack.

  6. Variability of the specific fluorescence of chlorophyll in the ocean. Part 2. Fluorometric method of chlorophyll a determination

    Directory of Open Access Journals (Sweden)

    Miros³awa Ostrowska

    2000-06-01

    Full Text Available Two methods of determining the chlorophyll a concentration in the sea have been formulated on the basis of artificially induced fluorescence measured with the aid of submersible fluorometers. The method of statistical correlation is founded on the empirical relationship between fluorescence and chlorophyll concentration. The theoretical model of fluorescence described in Part 1 of this paper (see Ostrowska et al. 2000, this volume provides the basis of the other method, the physical method. This describes the dependence of the specific fluorescence of phytoplankton on the chlorophyll concentration, a diversity of photophysiological properties of phytoplankton and the optical characteristics of the fluorometer.     In order to assess their practicability, the methods were subjected to empirical verification. This showed that the physical method yielded chlorophyll concentrations of far greater accuracy. The respective error factors of the estimated chlorophyll concentration were x = 2.07 for the correlation method and x = 1.5 for the physical method. This means that the statistical logarithmic error varies from -52 to +107% in the case of the former method but only from -33 to +51% in the case of the latter. Thus, modifying the methodology has much improved the accuracy of chlorophyll determinations.

  7. Simultaneous determination of nabumetone and its principal metabolite in medicines and human urine by time-resolved fluorescence.

    Science.gov (United States)

    Murillo Pulgarín, José Antonio; Alañón Molina, Aurelia; Martínez Ferreras, Fernando

    2012-11-07

    A simple fluorescent methodology for the simultaneous determination of nabumetone and its main metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA), in pharmaceutical preparations and human urine is proposed. Due to the strong overlapping between the fluorescence spectra of both analytes, the use of fluorescence decay curves to resolve their mixture is proposed, since these curves are more selective. Values of dependent instrumental variables affecting the signal-to-noise ratio were fixed using a simplex optimization procedure. A factorial design with three levels per factor coupled to a central composite design was selected to obtain a calibration matrix of thirteen standards plus one blank sample that was processed using a partial least-squares (PLS) analysis. In order to assess the goodness of the proposed method, a prediction set of ten synthetic samples was analyzed, obtaining recovery percentages between 97 and 105%. Limits of detection, calculated by means of a new criterion, were 0.96 μg L(-1) and 0.88 μg L(-1) for nabumetone and 6-MNA, respectively. The method was also tested in the pharmaceutical preparation Relif, which contains nabumetone, obtaining recovery percentages close to 100%. Finally, the simultaneous determination of both analytes in human urine samples was successfully carried out by the PLS-analysis of a matrix of fifteen standards plus four analyte blanks and the use of the standard addition technique. Although urine shows native fluorescence, no extraction method or prior separation of the analytes was needed.

  8. Simultaneous determination of 2-naphthoxyacetic acid and indole-3-acetic acid by first derivation synchronous fluorescence spectroscopy.

    Science.gov (United States)

    Liu, Xiangxiang; Wan, Yiqun

    2013-07-01

    A simple, rapid, sensitive and selective method for simultaneously determining 2-naphthoxyacetic acid (BNOA) and Indole-3-Acetic Acid (IAA) in mixtures has been developed using derivation synchronous fluorescence spectroscopy based on their synchronous fluorescence. The synchronous fluorescence spectra were obtained with Δλ=100 nm in a pH 8.5 NaH2PO4-NaOH buffer solution, and the detected wavelengths of quantitative analysis were set at 239 nm for BNOA and 293 nm for IAA respectively. The over lapped fluorescence spectra were well separated by the synchronous derivative method. Under optimized conditions, the limits of detection (LOD) were 0.003 μg/mL for BNOA and 0.012 μg/mL for IAA. This method is simple and expeditious, and it has been successfully applied to the determination of 2-naphthoxyacetic acid and indole-3-acetic acid in fruit juice samples with satisfactory results. The samples were only filtrated through a 0.45 μm membrane filter, which was free from the tedious separation procedures. The obtaining recoveries were in the range of 83.88-87.43% for BNOA and 80.76-86.68% for IAA, and the relative standard deviations were all less than 5.0%. Statistical comparison of the results with high performance liquid chromatography Mass Spectrometry (HPLC-MS) method revealed good agreement and proved that there were no significant difference in the accuracy and precision between these two methods.

  9. Simultaneous determination of 2-naphthoxyacetic acid and indole-3-acetic acid by first derivation synchronous fluorescence spectroscopy

    Science.gov (United States)

    Liu, Xiangxiang; Wan, Yiqun

    2013-07-01

    A simple, rapid, sensitive and selective method for simultaneously determining 2-naphthoxyacetic acid (BNOA) and Indole-3-Acetic Acid (IAA) in mixtures has been developed using derivation synchronous fluorescence spectroscopy based on their synchronous fluorescence. The synchronous fluorescence spectra were obtained with Δλ = 100 nm in a pH 8.5 NaH2PO4-NaOH buffer solution, and the detected wavelengths of quantitative analysis were set at 239 nm for BNOA and 293 nm for IAA respectively. The over lapped fluorescence spectra were well separated by the synchronous derivative method. Under optimized conditions, the limits of detection (LOD) were 0.003 μg/mL for BNOA and 0.012 μg/mL for IAA. This method is simple and expeditious, and it has been successfully applied to the determination of 2-naphthoxyacetic acid and indole-3-acetic acid in fruit juice samples with satisfactory results. The samples were only filtrated through a 0.45 μm membrane filter, which was free from the tedious separation procedures. The obtaining recoveries were in the range of 83.88-87.43% for BNOA and 80.76-86.68% for IAA, and the relative standard deviations were all less than 5.0%. Statistical comparison of the results with high performance liquid chromatography Mass Spectrometry (HPLC-MS) method revealed good agreement and proved that there were no significant difference in the accuracy and precision between these two methods.

  10. Electrolyzing synthesis of boron-doped graphene quantum dots for fluorescence determination of Fe(3+) ions in water samples.

    Science.gov (United States)

    Chen, Li; Wu, Chuanli; Du, Pan; Feng, Xiaowei; Wu, Ping; Cai, Chenxin

    2017-03-01

    This work reports a facile electrolyzing method to synthesize boron-doped graphene quantum dots (BGQDs) and uses the BGQDs as a fluorescent probe to determine Fe(3+) ion levels in water samples. The BGQDs were produced by oxidizing graphite in an aqueous borax solution at pH 7; then, the borate solution was filtered with BGQDs, and the borate was dialyzed from the filtrate, leaving a solution of BGQDs in water. The amount of the B in the BGQDs can be adjusted by changing the concentration of borax used for the electrolyte. The excitation wavelength- and B amount-dependent fluorescence characteristics of BQGDs were studied. The fluorescence intensity of the BGQDs is measurable in real time, and its quenching is very sensitive to the concentration of Fe(3+) ions in the system but not to other possible coexisting metal ions. The fluorescence quenching mechanism of Fe(3+) ions to BGQDs is studied and explained based on electrochemical voltammetry and DFT simulations. The analytical signal, which is defined as F0/F, where F0 and F are the fluorescence intensities of the BGQDs before and after interaction with Fe(3+) ions, respectively, displays a good linear relationship in the Fe(3+) ion concentration range of 0.01-100µm with a correlation coefficient of 0.999 and a limit of detection (LOD) of ~(0.005±0.001) μM. The LOD value is much lower than the water quality standards for Fe(3+) ions (0.3ppm, ~5.36µm) in drinking water suggested by the WHO (World Health Organization) and EPA (U.S. Environmental Protection Agency), implying that this method has great potential for applications in real sample assays. For example, the determination of the Fe(3+) ion levels in three water samples (tap water, groundwater, and lake water) gives approximately the same results as those determined by the EPA-recommended AAS (atomic adsorption spectroscopy) method.

  11. Uranium Determination in Samples from Decommissioning of Nuclear facilities Related to the First Stage of Nuclear Fuel Cycle; Determinacion de Uranio en Muestras Procedentes del Desmantelamiento de Instalaciones de la Primera Parte del Cielo del Combustible Nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, A.; Correa, E.; Navarro, N.; Sancho, C. [Ciemat, Madrid (Spain); Angeles, A.

    2000-07-01

    An adequate workplace monitoring must be carried out during the decommissioning activities, to ensure the protection of workers involved in these tasks. In addition, a large amount of waste materials are generated during the decommissioning of nuclear facilities. Clearance levels are established by regulatory authorities and are normally quite low. The determination of those activity concentration levels become more difficult when it is necessary to quantify alpha emitters such as uranium, especially when complex matrices are involved. Several methods for uranium determination in samples obtained during the decommissioning of a facility related to the first stage of the nuclear fuel cycle are presented in this work. Measurements were carried out by laboratory techniques. In situ gamma spectrometry was also used to perform measurements on site. A comparison among the different techniques was also done by analysing the results obtained in some practical applications. (Author)

  12. Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples.; Determinacion de U (Natural), Th (Natural) y Ra-226 en diversos materiales, mediante espectrometria con INa (TI)

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1991-07-01

    A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs.

  13. Determination of 238u/235u, 236u/238u and uranium concentration in urine using sf-icp-ms and mc-icp-ms: an interlaboratory comparison.

    Science.gov (United States)

    Parrish, Randall R; Thirlwall, Matthew F; Pickford, Chris; Horstwood, Matthew; Gerdes, Axel; Anderson, James; Coggon, David

    2006-02-01

    Accidental exposure to depleted or enriched uranium may occur in a variety of circumstances. There is a need to quantify such exposure, with the possibility that the testing may post-date exposure by months or years. Therefore, it is important to develop a very sensitive test to measure precisely the isotopic composition of uranium in urine at low levels of concentration. The results of an interlaboratory comparison using sector field (SF)-inductively coupled plasma-mass spectrometry (ICP-MS) and multiple collector (MC)-ICP-MS for the measurement of uranium concentration and U/U and U/U isotopic ratios of human urine samples are presented. Three urine samples were verified to contain uranium at 1-5 ng L and shown to have natural uranium isotopic composition. Portions of these urine batches were doped with depleted uranium (DU) containing small quantities of U, and the solutions were split into 100 mL and 400 mL aliquots that were subsequently measured blind by three laboratories. All methods investigated were able to measure accurately U/U with precisions of approximately 0.5% to approximately 4%, but only selected MC-ICP-MS methods were capable of consistently analyzing U/U to reasonable precision at the approximately 20 fg L level of U abundance. Isotope dilution using a U tracer demonstrates the ability to measure concentrations to better than +/-4% with the MC-ICP-MS method, though sample heterogeneity in urine samples was shown to be problematic in some cases. MC-ICP-MS outperformed SF-ICP-MS methods, as was expected. The MC-ICP-MS methodology described is capable of measuring to approximately 1% precision the U/U of any sample of human urine over the entire range of uranium abundance down to <1 ng L, and detecting very small amounts of DU contained therein.

  14. Determination of uranium isotopic composition and 236U content of soil samples and hot particles using inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Boulyga, S F; Becker, J S

    2001-07-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The 236U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10(-4) and 10(-3) counts per atom were achieved for 238U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH+/U+ was 1.2 x 10(-4) and 1.4 x 10(-4), respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 microg L(-1) NBS U-020 standard solution was 0.11% (238U/235U) and 1.4% (236U/238U) using a MicroMist nebulizer and 0.25% (235U/238U) and 1.9% (236U/P38U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the 236U/238U ratio ranged from 10(-5) to 10(-3). Results obtained with ICP-MS, alpha- and gamma-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples.

  15. Localization of GroEL determined by in vivo incorporation of a fluorescent amino acid

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Wang, Jiangyun; Brustad, Eric

    2011-01-01

    Escherichia coli cells, indicated colocalization with the cell division protein FtsZ at the cleavage furrow, while a second E. coli study of fixed cells indicated more even distribution throughout the cytoplasm. Here, for the first time, we have examined the spatial distribution of GroEL in living cells using......The molecular chaperone GroEL is required for bacterial growth under all conditions, mediating folding assistance, via its central cavity, to a diverse set of cytosolic proteins; yet the subcellular localization of GroEL remains unresolved. An earlier study, using antibody probing of fixed...... incorporation of a fluorescent unnatural amino acid into the chaperone. Fluorescence microscopy indicated that GroEL is diffusely distributed, both under normal and stress conditions. Importantly, the present procedure uses a small, fluorescent unnatural amino acid to visualize GroEL in vivo, avoiding...

  16. Contribution to the spectrographic determination of impurities in uranium by the carrier distillation method; Nuevas aportaciones a la determinacion espectrografica de impurezas en materiales de uranio por el metodo de distilacion fraccionada con portador

    Energy Technology Data Exchange (ETDEWEB)

    Capdevila, C.

    1967-07-01

    The carrier distillation method for the determination of impurities in uranium has been modified in order to get a greater sensitivity. Electrodes 9.5 mm. diam. with a crater 7 mm. diam. and 10 mm. deep have been used, being the weigh of charge 300 mg.. The elements considered were: Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Pb, Si, Sn, Ti and V, over the range 0.01 to 30 ppm. (Author) 13 refs.

  17. Determination of ethinylestradiol and levonorgestrel in oral contraceptives with HPLC methods with UV detection and UV/fluorescence detection

    Directory of Open Access Journals (Sweden)

    Zorica Arsova-Sarafinovska

    2006-06-01

    Full Text Available Oral contraceptives are pharmaceutical formulations containing an estrogen in a small amount and a synthetic progestin in 5-30 times bigger amount. A sensitive, accurate and rapid method for determination of active compounds is required. We have developed HPLC methods for determination of ethinylestradiol (EED and levonorgestrel (LNG in commercially available tablets. Chromatographic separation was performed on a Purospher® STAR RP-18e reversed-phase column (150 X 4.0 mm I.D.; particle size 5 µm in an isocratic mode with a mobile phase constituted of 47% acetonitrile: 53% water (V/V for both methods. The elution was carried out at a flow rate of 1.50 ml /min. All analyses were performed at room temperature (24 +/- 2°C. In the HPLC method with UV detection (internal standard method both compounds were detected at 215 nm. Drospirenone was used as an internal standard. In HPLC method with UV/fluorescence detection (external standard method LNG was monitored at 242 nm, while EED was detected with fluorescence detector at 310 nm (excitation 285 nm. The methods’ performances were fully validated by a determination of linearity, reproducibility, accuracy and sensitivity. Both methods were applied for determination of Uniformity of Dosage Units. The results obtained with both methods were highly comparable. However, the HPLC method with UV/ fluorescence detection has showed superior sensitivity for EED indicated by 83 times lower detection limit. HPLC method with UV/ fluorescence detection could be recommended as a method of choice for determination of ethinylestradiol, present at a very low dosage level in low-dose oral contraceptives, that also contain bigger amount of synthetic progestin.

  18. Uranium and free trade

    Energy Technology Data Exchange (ETDEWEB)

    1988-08-01

    This report was prepared by a working group of the Committee on International Trade in Uranium of the Uranium Institute. The report describes the general benefits of free trade and their relevance in the uranium market, and compares government restrictions on Western world uranium trade with those in other commodity markets. It is not directly concerned with restrictions designed to discourage nuclear weapons proliferation. The Uranium Institute and its members fully support the objective of nuclear non-proliferation. The report takes as given the current non-proliferation regime and focuses on economic and commercial restrictions imposed by governments on international trade in uranium, recognising that governments will always have a special interest in uranium trade owing to its potential weapons use. (author).

  19. Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.

    Science.gov (United States)

    Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-12-15

    A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples.

  20. Determination of Isotopic Composition of Uranium and Plutonium in Simulated 1AF Feed Solution by TIMS%TIMS测定模拟1AF料液中铀钚同位素组分

    Institute of Scientific and Technical Information of China (English)

    蒋军清; 高月华; 汪南杰; 姜国杜

    2012-01-01

    The precise determination of the uranium and plutonium isotopic composition in the simulated 1AF feed solution by solvent extraction/ion exchange separation-thermal ioni-zation mass spectroscopy(TIMS) was studied in this paper. The precise determination of uranium and plutonium isotopic composition was realized by optimization of chemical separations, and minimization of possible interferences, and proper selection of instrument parameters. Under the selected conditions, the uranium and plutonium isotopic composition in the 1AF feed solution were accurately determined. The relative standard deviations of the main isotopes 235U and 239Pu are less than 0. 05%.%采用溶剂萃取/离子交换分离-热表面电离质谱法,对模拟1AF料液中铀钚同位素组分测定技术进行了研究.通过对化学分离条件、仪器测量参数、信号强度、各种干扰等测定条件的研究和选择,实现了铀、钚同位素组分的精密测定.在选定的条件下,测定了模拟1AF料液中的铀钚同位素,主要同位素235 U和239pu测定精密度(sr)均优于0.05%.

  1. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  2. Sensitive determination of specific radioactivity of positron emission tomography radiopharmaceuticals by radio high-performance liquid chromatography with fluorescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Ryuji [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)], E-mail: nakaor@nirs.go.jp; Furutsuka, Kenji [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Sumitomo Accelerator Service, Tokyo 141-8686 (Japan); Yamaguchi, Masatoshi [Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180 (Japan); Suzuki, Kazutoshi [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2008-10-15

    A sensitive quality control method is often required in positron emission tomography (PET) radiopharmaceutical analysis due to the high specific radioactivity of synthetic products. The applicability of a radio high-performance liquid chromatography (HPLC) method with fluorescence detection was evaluated for a wide variety of PET radiopharmaceuticals. In 29 different radiopharmaceuticals studied, 20 compounds exhibited native fluorescence. These properties enabled sensitive determination of their chemical masses by direct fluorimetric detection after separation by HPLC. For some substances, detection limits were below nanograms per milliliter level, at least 40 times better than current UV absorbance detection. Sufficient reproducibility and linearity were obtained for the analysis of pharmaceutical fluid. Post-column fluorimetric derivatization was also established for the quantitative determination of FDG and ClDG in [{sup 18}F]FDG samples. These methods could be applied successfully to the analysis of PET radiopharmaceuticals with ultra-high specific radioactivity.

  3. Ag Nanoparticles-enhanced Fluorescence of Terbium-Deferasirox Complexes for the Highly Sensitive Determination of Deferasirox.

    Science.gov (United States)

    Abolhasani, Jafar; Naderali, Roza; Hassanzadeh, Javad

    2016-01-01

    We describe the effect of different sized gold and silver nanoparticles on the terbium sensitized fluorescence of deferasirox. It is indicated that silver nanostructures, especially 18 nm Ag nanoparticles (AgNPs), have a remarkable amplifying effect compared to Au nanoparticles. Based on this observation, a highly sensitive and selective method was developed for the determination of deferasirox. Effects of various parameters like AgNPs and Tb(3+) concentration and pH of media were investigated. Under the optimal conditions, a calibration curve was plotted as the fluorescence intensities versus the concentration of deferasirox in the range of 0.1 to 200 nmol L(-1), and detection limit of 0.03 nmol L(-1) was obtained. The method has good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of deferasirox in urine and pharmaceutical samples.

  4. Simultaneous determination of multiple (fluoro)quinolone antibiotics in food samples by a one-step fluorescence polarization immunoassay.

    Science.gov (United States)

    Mi, Tiejun; Wang, Zhanhui; Eremin, Sergei A; Shen, Jianzhong; Zhang, Suxia

    2013-10-02

    This paper describes a rapid one-step fluorescence polarization immunoassay (FPIA) for the simultaneous determination of multiple (fluoro)quinolone antibiotics (FQs) in food samples. Several fluorescent tracers were synthesized and evaluated in the FPIA method based on a broad-specificity of monoclonal antibodies toward FQs. The heterogeneous tracer, SAR-5-FAM, was considered as the optimal choice to prepare the immunocomplex single reagent, which allows a rapid and sensitive displacement reaction by addition of analytes. Optimized single-reagent FPIA exhibited broad cross-reactivities in the range of 7.8-172.2% with 16 FQs tested and was capable of determining most FQs at the level of maximum residue limits. Recoveries for spiked milk and chicken muscle samples were from 77.8 to 116%, with relative standard deviation lower than 17.4%. Therefore, this method could be applicable in routine screening analysis of multiple FQ residues in food samples.

  5. Uranium (III) precipitation in molten chloride by wet argon sparging

    Science.gov (United States)

    Vigier, Jean-François; Laplace, Annabelle; Renard, Catherine; Miguirditchian, Manuel; Abraham, Francis

    2016-06-01

    In the context of pyrochemical processes for nuclear fuel treatment, the precipitation of uranium (III) in molten salt LiCl-CaCl2 (30-70 mol%) at 705 °C is studied. First, this molten chloride is characterized with the determination of the water dissociation constant. With a value of 10-4.0, the salt has oxoacid properties. Then, the uranium (III) precipitation using wet argon sparging is studied. The salt is prepared using UCl3 precursor. At the end of the precipitation, the salt is totally free of solubilized uranium. The main part is converted into UO2 powder but some uranium is lost during the process due to the volatility of uranium chloride. The main impurity of the resulting powder is calcium. The consequences of oxidative and reductive conditions on precipitation are studied. Finally, coprecipitation of uranium (III) and neodymium (III) is studied, showing a higher sensitivity of uranium (III) than neodymium (III) to precipitation.

  6. Forms of uranium associated to silica in the environment of the Nopal deposit (Mexico)

    Science.gov (United States)

    Allard, T.; Othmane, G.; Menguy, N.; Vercouter, T.; Morin, G.; Calas, G.; Fayek, M.

    2011-12-01

    The understanding of the processes that control the transfers of uranium in the environment is necessary for the safety assessement of nuclear waste repositories. In particular, several poorly ordered phases (e.g. Fe oxihydroxides) are expected to play an important role in trapping uranium from surface waters. Among them, natural systems containing amorphous silica are poorly documented. A former study from the environment of the Peny mine (France) showed the importance of silica in uranium speciation [1]. The Nopal uranium deposit is located in volcanic tuff from tertiary period. It hosted several hydrothermal alteration episodes responsible for clay minerals formation. A primary uranium mineralisation occurred in a breccia pipe, consisting in uraninite, subsequently altered in secondary uranium minerals among which several silicates. Eventually, opal was formed and coated uranyl silicates such as uranophane and weeksite [2], [3]. Opals also contain minor amounts of uranium. The Nopal deposit is still considered as a natural analogue of high level nuclear waste repository located in volcanic tuff. It may be used to reveal the low temperature conditions of trapping of uranium in systems devoid of iron oxides such as silica-containing ones. The aim of this study is then to determine the uranium speciation, and its possible complexity, associated to these opals that represent a late trapping episode. It will provide insights ranging from the micrometer scale of electron microscopies to the molecular scale provided by fluorescence spectroscopy. Three samples of green or yellow opals have been analysed by a combination of complementary tools including scanning electron microscopy (SEM) on cross-sections, transmission electron microscopy (TEM) on focused ion beam (FIB) films, cathodoluminescence and time-resolved laser fluorescence spectroscopy (TRLFS). Uranium speciation was found to be complex. We first evidence U-bearing microparticles of beta-uranophane Ca[(UO2)(Si

  7. 利用 HPGe 铀能谱88~100 keV 能区确定铀富集度方法研究%Research on Uranium Enrichment Determination Using 88-100 keV Region of HPGe Uranium Spectrum

    Institute of Scientific and Technical Information of China (English)

    周浩; 赵永刚; 李建华; 金惠民

    2014-01-01

    利用铀材料γ能谱88~100 keV能区中γ、X射线重峰分解确定同位素丰度的方法,是铀同位素分析商用软件MGAU、MGA++等的核心技术。本文建立了γ、X射线峰形模型,提出了效率拟合因子修正效率的方法,并自行编写了铀富集度分析程序。用 H PGe γ谱仪对两种化学形态、铀富集度范围为1.80%~90.1%的铀样品进行了测量,以验证自编程序的可行性。利用本文所编写的程序分析实验能谱,得到的芯块样品分析结果与标称值的相对偏差小于2%,粉末样品分析结果与标称值的相对偏差小于1%。%T he method w hich is used to determine uranium enrichment by deconvoluting complex peak clusters in 88-100 keV region of γ/X spectrum of uranium materials is the key technique of some uranium enrichment determination software ,such as MGAU , MGA + + ,etc .According to the basic principle of this method ,a code to analyze the spectrum was written ,in which peak shape model of γ/X ray was built to fit the spec-trum and efficiency fitting factor was developed to make efficiency correction . Two types of uranium samples with enrichment ranging from 1.80% to 90.1% were meas-ured by a HPGe detector and analyzed by the code . For the samples measured , the uranium enrichment was determined with relative deviation of about 2% for pellet and 1% for pow der samples .

  8. Determination of level widths in 15N using nuclear resonance fluorescence

    Directory of Open Access Journals (Sweden)

    Szücs T.

    2015-01-01

    Full Text Available Level widths in 15N have been measured with the nuclear resonance fluorescence (NRF technique. Solid nitrogen compounds, bremsstrahlung, and HPGe detectors have been used as target, beam, and detectors, respectively. The preliminarily level widths are in agreement with the literature values, but more precise.

  9. Fo-spectra of chlorophyll fluorescence for the determination of zooplankton grazing

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Verschoor, A.M.

    2003-01-01

    In the PHYTO-PAM phytoplankton analyzer the minimal fluorescence of dark-adapted samples (F-0) was assessed, which gives direct information on the chlorophyll-a content. Clearance rates (CR) of Daphnia and Brachionus were calculated from a decrease in chlorophyll-a concentration using the PHYTO-PAM

  10. FO-spectra of chlorophyll fluorescence for the determination of zooplankton grazing

    NARCIS (Netherlands)

    Lürling, M.; Verschoor, A.M.

    2003-01-01

    In the PHYTO-PAM phytoplankton analyzer the minimal fluorescence of dark-adapted samples (F0) was assessed, which gives direct information on the chlorophyll- a content. Clearance rates (CR) of Daphnia and Brachionus were calculated from a decrease in chlorophyll-a concentration using the PHYTO-PAM

  11. Quantitative determination of uric acid using CdTe nanoparticles as fluorescence probes.

    Science.gov (United States)

    Jin, Dongri; Seo, Min-Ho; Huy, Bui The; Pham, Quoc-Thai; Conte, Maxwell L; Thangadurai, Daniel; Lee, Yong-Ill

    2016-03-15

    A convenient enzymatic optical method for uric acid detection was developed based on the fluorescence quenching of ligand-capped CdTe nanoparticles by H2O2 which was generated from the enzymatic reaction of uric acid. The interactions between the CdTe nanoparticles capped with different ligands (glutathione, 3-mercaptopropionic acid, and thioglycerol) and H2O2 were investigated. The fluorescence quenching studies of GSH-capped CdTe nanoparticles demonstrated an excellent sensitivity to H2O2. The effects of uric acid, uricase and H2O2 on the fluorescence intensity of CdTe nanoparticles were also explored. The detection conditions, reaction time, pH value, incubation period and the concentration of uricase and uric acid were optimized. The detection limit of uric acid was found to be 0.10 µM and the linear range was 0.22-6 µM under the optimized experimental conditions. These results typify that CdTe nanoparticles could be used as a fluorescent probe for uric acid detection.

  12. Determination of Polycyclic Aromatic Hydrocarbons in Automobile Exhaust by Means of High-Performance Liquid Chromatography with Fluorescence Detection

    DEFF Research Database (Denmark)

    Nielsen, Tom

    1979-01-01

    A chromatographic method has been developed and applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in particulate matter in automobile exhaust, in petrols, and in crankcase oils. The PAHs were purified from other organic compounds by thin-layer chromatography, separated by high......-performance liquid chromatography, and measured by means of on-line fluorescence detection. The identities of the PAHs were verified by comparing the emission spectra obtained by a stop-flow technique with those of standard PAHs...

  13. Uranium(VI) Binding Forms in Selected Human Body Fluids: Thermodynamic Calculations versus Spectroscopic Measurements.

    Science.gov (United States)

    Osman, Alfatih A A; Geipel, Gerhard; Barkleit, Astrid; Bernhard, Gert

    2015-02-16

    Human exposure to uranium increasingly becomes a subject of interest in many scientific disciplines such as environmental medicine, toxicology, and radiation protection. Knowledge about uranium chemical binding forms(speciation) in human body fluids can be of great importance to understand not only its biokinetics but also its relevance in risk assessment and in designing decorporation therapy in the case of accidental overexposure. In this study, thermodynamic calculations of uranium speciation in relevant simulated and original body fluids were compared with spectroscopic data after ex-situ uranium addition. For the first time, experimental data on U(VI) speciation in body fluids (saliva, sweat, urine) was obtained by means of cryogenic time-resolved laser-induced fluorescence spectroscopy (cryo-TRLFS) at 153 K. By using the time dependency of fluorescence decay and the band positions of the emission spectra, various uranyl complexes were demonstrated in the studied samples. The variations of the body fluids in terms of chemical composition, pH, and ionic strength resulted in different binding forms of U(VI). The speciation of U(VI) in saliva and in urine was affected by the presence of bioorganic ligands, whereas in sweat, the distribution depends mainly on inorganic ligands. We also elucidated the role of biological buffers, i.e., phosphate (H(2)PO(4−)/HPO(4)(2−)) on U(VI) distribution, and the system Ca(2+)/UO(2)(2+)/PO(4)(3−) was discussed in detail in both saliva and urine. The theoretical speciation calculations of the main U(VI) species in the investigated body fluids were significantly consistent with the spectroscopic data. Laser fluorescence spectroscopy showed success and reliability for direct determination of U(VI) in such biological matrices with the possibility for further improvement.

  14. Separation and determination of lanthanides, thorium and uranium using a dual gradient in reversed-phase liquid chromatography.

    Science.gov (United States)

    Raut, Narendra M; Jaison, P G; Aggarwal, Suresh K

    2004-10-15

    Separation and determination of lanthanides, Th and U is of great relevance in different fields of science and technology. Reversed-phase high-performance liquid chromatography (RP-HPLC) using alpha-hydroxy isobutyric acid (alpha-HIBA) as an eluent on reversed-phase column modified to cation exchanger has been reported to achieve the separation. However, under those conditions, Th and U are eluted amongst lanthanides, making their quantification difficult due to overlapping with some of the lanthanides peaks. In this work, different chromatographic parameters (concentrations of eluent and ion interaction reagent, pH, etc.) were studied systematically to arrive at optimum chromatographic conditions. Using the dual (concentration and pH) gradient conditions, lanthanides, Th and U could be separated in 11 min by RP-HPLC with sequential elution of Th and U after the elution of all the lanthanides. The separation methodology was tested using SY-3 rock sample for the separation and determination of lanthanides, Th and U. The method allows an accurate determination of these elements in a single run using a single column. Also, the method is fast and cost-effective compared to the reported methods.

  15. Turn-on fluorescence probes based on pyranine/viologen charge-transfer complexes for the determination of nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Schäferling, Michael, E-mail: Michael.schaeferling@utu.fi; Lang, Thomas; Schnettelker, Annette

    2014-10-15

    The formation of ground state charge-transfer complexes between pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid) and viologen (paraquat) derivatives is utilized for the design of novel fluoroionophores for the determination of phosphate species, particularly of nucleotides. The strong quenching of the pyranine fluorescence by viologen-type charge transfer acceptors can be countermanded if these are functionalized with triethylammonium groups that serve as recognition elements for phosphate anions. We report on the fluorogenic responses of these water-soluble molecular probes in presence of different phosphates. Absorbance measurements give additional information on the charge transfer complex formation and the interaction with nucleotides. The experimental data show that these aggregates form attractive, simple and versatile fluorescence turn-on probes for nucleoside triphosphates. The reversibility of the fluorescence response is demonstrated by means of an enzymatic model assay using ATPase for the decomposition of adenosine triphosphate. - Highlights: • Pyranine/viologen charge-transfer complexes as molecular probe for ATP recognition. • Fluorescence turn on mechanism. • Selective compared to other nucleotides and phosphate anions. • Fast and reversible response applicable to monitor enzymatic reactions.

  16. Determination of Albumin Using CdS/SiO2 Core/shell Nanoparticles as Fluorescence Probes

    Institute of Scientific and Technical Information of China (English)

    ZHU Changqing; LIU Meigui; WANG Peng; CAO Ming; CAO Chun

    2009-01-01

    CdS quantum dots(QD)were capped with SiO2 via a microemulsion method for reducing the toxicity and imparting the biocompatibility of the CdS QD.The resulting CdS/SiO2 core/shell nanoparticles(NP)showed an improved water-solubility and stability even in pH 4.0 acidic medium.Their fluorescence could be effectively enhanced in the presence of bovine serum albumin(BSA),due to the passivation effect of BSA on the surface of the NP.Furthermore,the concentration dependence of the fluorescence intensity obeys the Langmuir-type binding isotherm.Thus a novel fluorescence enhancement method for the determination of BSA has been developed using the less-toxic CdS/SiO2 core/shell NP as probes.Under optimal conditions,the linear range of calibration curve is 0.6the CdS/SiO2 core/shell NP exhibited slightly lower fluorescence response to BSA as well as other coexisting substances,such as heavy and transition metals,due to the inhibition of SiO2 shell.The proposed method was applied to the quantification of BSA in synthetic and serum samples with satisfactory results.

  17. Experimental determination of photostability and fluorescence-based detection of PAHs on the Martian surface

    Science.gov (United States)

    Dartnell, Lewis R.; Patel, Manish R.; Storrie-Lombardi, Michael C.; Ward, John M.; Muller, Jan-Peter

    2012-05-01

    Even in the absence of any biosphere on Mars, organic molecules, including polycyclic aromatic hydrocarbons (PAHs), are expected on its surface due to delivery by comets and meteorites of extraterrestrial organics synthesized by astrochemistry, or perhaps in situ synthesis in ancient prebiotic chemistry. Any organic compounds exposed to the unfiltered solar ultraviolet spectrum or oxidizing surface conditions would have been readily destroyed, but discoverable caches of Martian organics may remain shielded in the subsurface or within surface rocks. We have studied the stability of three representative polycyclic aromatic hydrocarbons (PAHs) in a Mars chamber, emulating the ultraviolet spectrum of unfiltered sunlight under temperature and pressure conditions of the Martian surface. Fluorescence spectroscopy is used as a sensitive indicator of remaining PAH concentration for laboratory quantification of molecular degradation rates once exposed on the Martian surface. Fluorescence-based instrumentation has also been proposed as an effective surveying method for prebiotic organics on the Martian surface. We find the representative PAHs, anthracene, pyrene, and perylene, to have persistence half-lives once exposed on the Martian surface of between 25 and 60 h of noontime summer UV irradiation, as measured by fluorescence at their peak excitation wavelength. This equates to between 4 and 9.6 sols when the diurnal cycle of UV light intensity on the Martian surface is taken into account, giving a substantial window of opportunity for detection of organic fluorescence before photodegradation. This study thus supports the use of fluorescence-based instrumentation for surveying recently exposed material (such as from cores or drill tailings) for native Martian organic molecules in rover missions.

  18. Bacterial diversity in soil samples from two uranium waste piles as determined by rep-APD, RISA and 16S rDNA retrieval.

    Science.gov (United States)

    Selenska-Pobell, S; Kampf, G; Hemming, K; Radeva, G; Satchanska, G

    2001-06-01

    The bacterial diversity in two uranium waste piles was studied. Total DNA was recovered from a large number of soil samples collected from different sites and depths in the piles using two procedures for direct lysis. Significant differences in the bacterial composition of the samples were revealed by the use of rep-APD, RISA and 16S ARDREA. The 16S rDNA analyses showed that the uranium wastes were dominated by Acidithiobacillusferrooxidans and by several Pseudomonas species classified in the gamma-subdivision of the Proteobacteria. The three kinds of A. ferrooxidans 16S and IGS rDNA specific fragments that were found corresponded to the three phylogenetic groups recognised in this species. This microdiversity probably reflects the genetic adaptation of the uranium waste strains to different concentrations of heavy metals.

  19. Burn-Up Determination by High Resolution Gamma Spectrometry: Spectra from Slightly-Irradiated Uranium and Plutonium between 400-830 keV

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, R.S.; Ronqvist, N.

    1966-08-15

    Previously published studies of the short-cooled fission product spectra of irradiated uranium have been severely restricted by the poor energy resolution of the sodium iodide detectors used. In this report are presented fission product spectra of irradiated uranium and plutonium obtained by means of a lithium-drifted germanium detector. The resolved gamma peaks have been assigned to various fission products by correlation of measured energy and half-life values with published data. By simultaneous study of the spectra of two irradiated mixtures of plutonium and uranium, the possibility of using the activities of Ru-103 and Ru-106 as a measure of the relative fission rate in U-235 and Pu-239 has been briefly examined.

  20. Determination of multiple phytohormones in fruits by high-performance liquid chromatography with fluorescence detection using dispersive liquid-liquid microextraction followed by precolumn fluorescent labeling.

    Science.gov (United States)

    Li, Guoliang; Lu, Shuaimin; Wu, Hongliang; Chen, Guang; Liu, Shucheng; Kong, Xiaojian; Kong, Weiheng; You, Jinmao

    2015-01-01

    Plant hormone determination in food matrices has attracted more and more attention because of their potential risks to human health. However, analytical methods for the analysis of multiple plant hormones remain poorly investigated. In the present study, a convenient, selective, and ultrasensitive high-performance liquid chromatography method for the simultaneous determination of multiple classes of plant hormones has been developed successfully using dispersive liquid-liquid microextraction followed by precolumn fluorescent labeling. Eight plant hormones in fruits including jasmonic acid, 12-oxo-phytodienoic acid, indole-3-acetic acid, 3-indolybutyric acid, 3-indolepropionic acid, gibberellin A3 , 1-naphthylacetic acid, and 2-naphthaleneacetic acid were analyzed by this method. The conditions employed for dispersive liquid-liquid microextraction were optimized systematically. The linearity for all plant hormones was found to be >0.9993 (R(2) values). This method offered low detection limits of 0.19-0.44 ng/mL (at a signal-to-noise ratio of 3), and method accuracies were in the range of 92.32-103.10%. The proposed method was applied to determine plant hormones in five kinds of food samples, and this method can achieve a short analysis time, low threshold levels of detection, and a high specificity for the analysis of targeted plant hormones present at trace level concentrations in complex matrices.

  1. Simultaneous spectrophotometric determination of trace amounts of uranium, thorium, and zirconium using the partial least squares method after their preconcentration by alpha-benzoin oxime modified Amberlite XAD-2000 resin.

    Science.gov (United States)

    Ghasemi, Jahan B; Zolfonoun, E

    2010-01-15

    A new solid phase extraction method for separation and preconcentration of trace amounts of uranium, thorium, and zirconium in water samples is proposed. The procedure is based on the adsorption of U(VI), Th(IV) and Zr(IV) ions on a column of Amberlite XAD-2000 resin loaded with alpha-benzoin oxime prior to their simultaneous spectrophotometric determination with Arsenazo III using orthogonal signal correction partial least squares method. The enrichment factor for preconcentration of uranium, thorium, and zirconium was found to be 100. The detection limits for U(VI), Th(IV) and Zr(IV) were 0.50, 0.54, and 0.48microgL(-1), respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of 10 replicates, was below 4% for all elements. The practical applicability of the developed sorbent was examined using synthetic seawater, natural waters and ceramic samples.

  2. Rapid Determination of 226Ra and Uranium Isotopes in Solid Samples by Fusion with Lithium Metaborate and Alpha Spectrometry

    Directory of Open Access Journals (Sweden)

    R. Bojanowski

    2002-01-01

    Full Text Available A simple and rapid method has been developed to determine 226Ra in rocks, soils, and sediments. Samples are decomposed by fusion with lithium metaborate and the melt is dissolved in a solution containing sulfates and citric acid. During the dissolution, a fine suspension of mixed barium and radium sulfates is formed. The microcrystals are collected on a membrane filter (pore size 0.1 μm and analysed in an alpha spectrometer. Application of a 133Ba tracer enables us to assess the loss of the analyte, which only rarely exceeds 10%. All analytical operations, beginning from sample decomposition to source preparation for alpha spectrometry, can be accomplished within 1 or 2 h.

  3. Uranium hexafluoride public risk

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

    1994-08-01

    The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

  4. Unexpected rates of chromosomal instabilities and alterations of hormone levels in Namibian uranium miners

    Energy Technology Data Exchange (ETDEWEB)

    Zaire, R.; Notter, M.; Thiel, E. [Free Univ., Berlin (Germany)] [and others

    1997-05-01

    A common problem in determining the health consequences of radiation exposure is factoring out other carcinogenic influences. The conditions in Namibia provide a test case for distinguishing the effects of long-term low-dose exposure to uranium from the other environmental factors because of good air quality and the lack of other industries with negative health effects. Present records indicate a much higher prevalence of cancer among male workers in the open-pit uranium mine in Namibia compared with the general population. The objective of the present study was to determine whether long-term exposure to low doses of uranium increases the risk of a biological radiation damage which would lead to malignant diseases and to derive a dose-response model for these miners. To investigate this risk, we measured uranium excretion in urine, neutrophil counts and the serum level of FSH, LH and testosterone and analyzed chromosome aberrations in whole blood cells using fluorescence in situ hybridization. A representative cohort of 75 non-smoking, HIV-negative miners was compared to a control group of 31 individuals with no occupational history in mining. A sixfold increase in uranium excretion among the miners compared to the controls was recorded (P < 0.001). Furthermore, we determined a significant reduction in testosterone levels (P < 0.008) and neutrophil count (P < 0.0001). Most remarkably, cells with multiple aberrations such as {open_quotes}rogue{close_quotes} cells were observed for the first time in miners; these cells had previously been found only after short-term high-dose radiation exposure, e.g. from the Hiroshima atomic bomb or the Chernobyl accident. 19 refs., 1 fig., 3 tabs.

  5. Bioremediation of uranium contamination with enzymatic uranium reduction

    Science.gov (United States)

    Lovley, D.R.; Phillips, E.J.P.

    1992-01-01

    Enzymatic uranium reduction by Desulfovibrio desulfuricans readily removed uranium from solution in a batch system or when D. desulfuricans was separated from the bulk of the uranium-containing water by a semipermeable membrane. Uranium reduction continued at concentrations as high as 24 mM. Of a variety of potentially inhibiting anions and metals evaluated, only high concentrations of copper inhibited uranium reduction. Freeze-dried cells, stored aerobically, reduced uranium as fast as fresh cells. D. desulfuricans reduced uranium in pH 4 and pH 7.4 mine drainage waters and in uraniumcontaining groundwaters from a contaminated Department of Energy site. Enzymatic uranium reduction has several potential advantages over other bioprocessing techniques for uranium removal, the most important of which are as follows: the ability to precipitate uranium that is in the form of a uranyl carbonate complex; high capacity for uranium removal per cell; the formation of a compact, relatively pure, uranium precipitate.

  6. Determination of poorly fluorescent carbamate pesticides in water, bendiocarb and promecarb, using cyclodextrin nanocavities and related media

    Energy Technology Data Exchange (ETDEWEB)

    Pacioni, Natalia L. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Veglia, Alicia V. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)]. E-mail: aveglia@mail.fcq.unc.edu.ar

    2007-01-30

    The effect of native cyclodextrins ({alpha}, {beta}, or {gamma}CD with six, seven and eight glucose units, respectively), hydroxypropyl-{beta}-cyclodextrin (HPCD), chitosan (CHT) and glucose in water solution or water with n-propylamine (PA) as co-solvent upon the UV-vis and fluorescence properties of poorly fluorescent N-methyl carbamates pesticides (C) as bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-ol methylcarbamate, BC) and promecarb (3-methyl-5-(1-methylethyl)phenol methylcarbame, PC) was examined. Fluorescent enhancement was found for both substrates with all CDs in water or PA-water except from PC with {alpha}CD. The addition of CHT increases the fluorescence of BC but decreases the fluorescence of PC, and glucose addition gives in both cases no spectral changes. Host-guest interaction was clearly determined by fluorescence enhancement with {beta}CD and HPCD with a 1:1 stoichiometry for the complexes (C:CD). The values obtained for the association constants (K {sub A}, M{sup -1}) were (6 {+-} 2) x 10{sup 2} and (2.3 {+-} 0.3) x 10{sup 2} for BC:{beta}CD and BC:HPCD complexes, respectively. For PC:{beta}CD and PC:HPCD the values of K {sub A} were (19 {+-} 2) x 10{sup 2} and (21 {+-} 2) x 10{sup 2}, respectively. The ratio of the fluorescence quantum yields for the bound and free substrates ({phi} {sup CCD}/{phi} {sup C}) was in the range 1.74-3.8. The limits of detection (L {sub D}, {mu}g mL{sup -1}) for the best conditions were (0.57 {+-} 0.02) for BC with HPCD and (0.091 {+-} 0.002) for PC with {beta}CD in water. Application to the analysis in pesticide spiked samples of tap water and fruit yields satisfactory apparent recoveries (84-114%), and for the extraction procedure in fruits and a commercial formulation, recoveries were of 81-98% and 104%, respectively. The method is rapid, simple, direct, sensitive and useful for pesticide analysis.

  7. The concentrations of uranium in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Matsuba, Mitsue; Ishii, Toshiaki; Nakahara, Motokazu; Nakamura, Ryoichi; Watabe, Teruhisa; Hirano, Shigeki [National Inst. of Radiological Sciences, Hitachinaka, Ibaraki (Japan). Laboratory for Radioecology

    2000-07-01

    Determination of uranium in sixty-one species of marine organisms was carried out by inductively coupled plasma mass spectrometry to obtain concentration factors and to estimate the internal radiation dose. The concentrations of uranium in soft tissues of marine animals were ranged from 0.077 to 5040 ng/g wet wt. Especially, the branchial heart of cephalopod molluscs showed the specific accumulation of uranium. The concentration factor of the branchial heart of Octopus vulgaris, which indicated the highest value, was calculated to be about 1.6 x 10{sup 3}, comparing with that (3.1 ng/ml) in coastal seawaters of Japan. The concentrations of uranium in hard tissues of marine invertebrates such as clam and sea urchin were similar to those in soft tissues. In contrast, hard tissues like bone, scale, fin, etc. of fishes showed much higher concentrations of uranium than soft tissues like muscle. The concentrations of uranium of twenty-two species of algae were ranged from 2 to 310 ng/g wet wt. Particularly, the brown alga Undaria pinnatifida showed the highest value of the uranium content in the algae and its concentration factor was calculated to be 10{sup 2}. (author)

  8. A sensitive fluorescence reagent for the determination of aldehydes from alcoholic beverage using high-performance liquid chromatography with fluorescence detection and mass spectrometric identification

    Energy Technology Data Exchange (ETDEWEB)

    You Jinmao [Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001 (China)], E-mail: Jmyou6304@163.com; Yan Tao; Zhao Huaixin [Key Laboratory of Life-Organic Analysis, College of Chemistry Science, Qufu Normal University, Qufu Shandong 273165 (China); Sun Zhiwei; Xia Lian; Suo Yourui; Li Yulin [Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001 (China)

    2009-03-16

    A pre-column derivatization method for the sensitive determination of aldehydes using the tagging reagent 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl carbonylhydrazine (DBCEEC) followed by high-performance liquid chromatography with fluorescence detection and APCI-MS identification has been developed. The chromophore of fluoren-9-methoxy-carbonylhydrazine (Fmoc-hydrazine) reagent was replaced by 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl functional group, which resulted in a sensitive fluorescence tagging reagent DBCEEC. DBCEEC could easily and quickly labeled aldehydes. The maximum excitation (300 nm) and emission (400 nm) wavelengths did not essentially change for all the aldehyde derivatives. Derivatives were sufficiently stable to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z [M + (CH{sub 2}){sub n}]{sup +} in positive-ion mode (M: molecular weight of DBCEEC, n: corresponding aldehyde carbon atom numbers). The collision-induced dissociation of protonated molecular ion formed fragment ions at m/z 294.6, m/z 338.6 and m/z 356.5. Studies on derivatization demonstrated excellent derivative yields in the presence of trichloroacetic acid (TCA) catalyst. Maximal yields close to 100% were observed with a 10 to 15-fold molar reagent excess. Separation of the derivatized aldehydes had been optimized on ZORBAX Eclipse XDB-C{sub 8} column with aqueous acetonitrile as mobile phase in conjunction with a binary gradient elution. Excellent linear responses were observed at the concentration range of 0.01-10 nmol mL{sup -1} with coefficients of >0.9991. Detection limits obtained by the analysis of a derivatized standard containing 0.01 nmol mL{sup -1} of each aldehyde, were from 0.2 to 1.78 nmol L{sup -1} (at a signal-to-noise ratio of 3)

  9. A sensitive fluorescence reagent for the determination of aldehydes from alcoholic beverage using high-performance liquid chromatography with fluorescence detection and mass spectrometric identification.

    Science.gov (United States)

    You, Jinmao; Yan, Tao; Zhao, Huaixin; Sun, Zhiwei; Xia, Lian; Suo, Yourui; Li, Yulin

    2009-03-16

    A pre-column derivatization method for the sensitive determination of aldehydes using the tagging reagent 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl carbonylhydrazine (DBCEEC) followed by high-performance liquid chromatography with fluorescence detection and APCI-MS identification has been developed. The chromophore of fluoren-9-methoxy-carbonylhydrazine (Fmoc-hydrazine) reagent was replaced by 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl functional group, which resulted in a sensitive fluorescence tagging reagent DBCEEC. DBCEEC could easily and quickly labeled aldehydes. The maximum excitation (300nm) and emission (400nm) wavelengths did not essentially change for all the aldehyde derivatives. Derivatives were sufficiently stable to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z [M+(CH(2))(n)](+) in positive-ion mode (M: molecular weight of DBCEEC, n: corresponding aldehyde carbon atom numbers). The collision-induced dissociation of protonated molecular ion formed fragment ions at m/z 294.6, m/z 338.6 and m/z 356.5. Studies on derivatization demonstrated excellent derivative yields in the presence of trichloroacetic acid (TCA) catalyst. Maximal yields close to 100% were observed with a 10 to 15-fold molar reagent excess. Separation of the derivatized aldehydes had been optimized on ZORBAX Eclipse XDB-C(8) column with aqueous acetonitrile as mobile phase in conjunction with a binary gradient elution. Excellent linear responses were observed at the concentration range of 0.01-10nmolmL(-1) with coefficients of >0.9991. Detection limits obtained by the analysis of a derivatized standard containing 0.01nmolmL(-1) of each aldehyde, were from 0.2 to 1.78nmolL(-1) (at a signal-to-noise ratio of 3).

  10. Investigation of capillary electrophoresis-laser induced fluorescence as a tool in the characterization of sewage effluent for fluorescent acids: determination of salicylic acid.

    Science.gov (United States)

    Flaherty, Sean; Wark, Shelly; Street, Ginger; Farley, John W; Brumley, William C

    2002-07-01

    The investigation of emerging contaminant issues is a proactive effort in environmental analysis. As a part of this effort, sewage effluent is of current analytical interest because of the presence of pharmaceuticals and their metabolites and personal care products. The environmental impact of these components is still under investigation but their constant perfusion into receiving waters and their potential effect on biota is of concern. This paper examines a tool for the characterization of sewage effluent using capillary electrophoresis-laser induced fluorescence (CE-LIF) with a frequency-doubled laser operated in the ultraviolet (UV). Fluorescent acidic analytes are targeted because they present special problems for techniques such as gas chromatography-mass spectrometry (GC-MS) but are readily accessible to CE-LIF. As an example of the application of this tool, salicylic acid is determined near the 100 ng/L (7 x 10(-10) M) level in sewage effluent. Salicylic acid is a metabolite of various analgesics. Relatively stable in the environment, it is a common contaminant of municipal sewage systems. Salicylic acid was recovered from freshly collected samples of the effluent by liquid-liquid extraction. Confirmation of identity was by electron ionization GC-MS after conversion of the salicylic acid to the methyl ester by means of trimethylsilyldiazomethane. CE-LIF in the UV has revealed more than 50 individual peaks in the extract and a background response that suggests a large and indeterminate number of additional compounds are present. These data together with complementary techniques provide information on the complexity and components in these effluent streams.

  11. Fusobacterium necrophorum determined as abortifacient in sheep by laser capture microdissection and fluorescence in situ hybridization

    DEFF Research Database (Denmark)

    Boye, Mette; Aalbæk, Bent; Agerholm, Jørgen S.

    2006-01-01

    at late pregnancy by a technique that combines laser capture microdissection (LCM) and fluorescent in situ hybridization (LCM-FISH). Cultural bacteriological examination had failed to identify an infectious agent but by histological examination, large colonies of bacteria associated with tissue......Fluorescent in situ hybridization (FISH) has been extensively used for identification of individual microbial cells within their natural environment. The present work describes the identification of Fusobacterium necrophorum in formalin-fixed tissue samples from three sets of ovine twins aborted......RNA-targeting oligonucleotide probe specific for F. necrophorum was used in a FISH assay. In situ hybridization showed a high density of F. necrophorum in all examined tissue sections. Simultaneous probing with a general bacterial probe EUB338 and the specific probe for F. necrophorum showed that no other bacteria could...

  12. Application of the Total Reflection X-ray Fluorescence technique to trace elements determination in tobacco

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, T. [National University of Mexico, Faculty of Chemistry, Building D, CU (O4510) Mexico, D.F. Mexico (Mexico)], E-mail: tmc@servidor.unam.mx; Lartigue, J. [National University of Mexico, Faculty of Chemistry, Building D, CU (O4510) Mexico, D.F. Mexico (Mexico); Zarazua, G.; Avila-Perez, P. [National Institute of Nuclear Research. Carr. Mexico-Toluca Km 36.5, (52045) Salazar, Ocoyoacac, Edo. de Mexico (Mexico); Navarrete, M. [National University of Mexico, Faculty of Chemistry, Building D, CU (O4510) Mexico, D.F. Mexico (Mexico); Tejeda, S. [National Institute of Nuclear Research. Carr. Mexico-Toluca Km 36.5, (52045) Salazar, Ocoyoacac, Edo. de Mexico (Mexico)

    2008-12-15

    Many studies have identified an important number of toxic elements along with organic carcinogen molecules and radioactive isotopes in tobacco. In this work we have analyzed by Total Reflection X-Ray Fluorescence 9 brands of cigarettes being manufactured and distributed in the Mexican market. Two National Institute of Standards and Technology standards and a blank were equally treated at the same time. Results show the presence of some toxic elements such as Pb and Ni. These results are compared with available data for some foreign brands, while their implications for health are discussed. It can be confirmed that the Total Reflection X-Ray Fluorescence method provides precise (reproducible) and accuracy (trueness) data for 15 elements concentration in tobacco samples.

  13. Determining a fluorophore's transition dipole moment from fluorescence lifetime measurements in solvents of varying refractive index.

    Science.gov (United States)

    Chung, Pei-Hua; Tregidgo, Carolyn; Suhling, Klaus

    2016-11-11

    The transition dipole moment of organic dyes PM546 and rhodamine 123 is calculated from fluorescence lifetime measurements in solutions of different refractive index. A model proposed by Toptygin et al (2002 J. Phys. Chem. B 106 3724-34) provides a relationship between the radiative rate constant and refractive index of the solvent, and allows the electronic transition dipole moments to be found: it is (7.1  ±  1.1) D for PM546 which matches that found in the literature, and (8.1  ±  0.1) D for rhodamine 123. Toptygin's model goes further in predicting the shape of the fluorescent dye and here we predict the shape of PM546 and rhodamine 123 to be ellipsoidal.

  14. Uranium conversion; Conversion de l`uranium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    This booklet is a presentation of the activities of the Comurhex company, created in 1971 and which became a 100% Cogema`s daughter company in 1992. The Comurhex company is in charge of the conversion of natural uranium into gaseous uranium hexafluoride (UF{sub 6}). The two steps of the conversion operation are performed in the Malvesi and Pierrelatte (France) industrial sites and represent 31% (14000 t/year) of the uranium conversion capacity of western countries. The refining and UF{sub 4} production (Malvesi) and the UF{sub 6} fabrication (Pierrelatte) processes are described. Comurhex is also one of the few companies in the world which produces UF{sub 6} from the uranium of spent fuels. (J.S.)

  15. Determination of Fission Products in Irradiated Fuel by X-Ray Fluorescence

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Als-Nielsen, Jens Aage; Andersen, Niels Hessel

    X-ray fluorescence i s a well e s t a b l i s h e d analytical tool for measuring elemental composition of fairly large (~ 5 cm2) "cold" samples. A version of t h i s technique has been developed for a n a l y s i s of radial d i s t r i b u t i o n of f i s s i o n products Xe, Cs and Ba in irra...

  16. High Frequency Acoustic Microscopy for the Determination of Porosity and Young's Modulus in High Burnup Uranium Dioxide Nuclear Fuel

    Science.gov (United States)

    Marchetti, Mara; Laux, Didier; Cappia, Fabiola; Laurie, M.; Van Uffelen, P.; Rondinella, V. V.; Wiss, T.; Despaux, G.

    2016-06-01

    During irradiation UO2 nuclear fuel experiences the development of a non-uniform distribution of porosity which contributes to establish varying mechanical properties along the radius of the pellet. Radial variations of both porosity and elastic properties in high burnup UO2 pellet can be investigated via high frequency acoustic microscopy. For this purpose ultrasound waves are generated by a piezoelectric transducer and focused on the sample, after having travelled through a coupling liquid. The elastic properties of the material are related to the velocity of the generated Rayleigh surface wave (VR). A UO2 pellet with a burnup of 67 GWd/tU was characterized using the acoustic microscope installed in the hot cells of the JRC-ITU at a 90 MHz frequency, with methanol as coupling liquid. VR was measured at different radial positions. A good agreement was found, when comparing the porosity values obtained via acoustic microscopy with those determined using SEM image analysis, especially in the areas close to the centre. In addition, Young's modulus was calculated and its radial profile was correlated to the corresponding burnup profile and to the hardness radial profile data obtained by Vickers micro-indentation.

  17. A selective fluorescent receptor for the determination of nickel (II) in semi-aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Fegade, Umesh [School of Chemical Sciences, North Maharashtra University, Jalgaon 425001, MS (India); School of Environmental and Earth Sciences, North Maharashtra University, Jalgaon 425001, MS (India); Marek, Jaromir [Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno (Czech Republic); Patil, Rahul [School of Chemical Sciences, North Maharashtra University, Jalgaon 425001, MS (India); Attarde, Sanjay [School of Environmental and Earth Sciences, North Maharashtra University, Jalgaon 425001, MS (India); Kuwar, Anil, E-mail: kuwaras@gmail.com [School of Chemical Sciences, North Maharashtra University, Jalgaon 425001, MS (India)

    2014-02-15

    The malonohydrazide based fluorescent probe (7E,8E)–N1′,N3′-bis(1-(2-hydroxyphenyl)ethylidene) malonohydrazide (receptor 5) was designed and synthesized. It was confirmed by spectroscopic methods and the single crystal X-ray method. The receptors 5 show strong intramolecular hydrogen bonding which is useful in host–guest complexation. The fluorescence spectra of receptor 5 have shown distinct enhancement with the addition of Ni{sup 2+} ion over other surveyed cations. The stability constant was obtained by Benesi–Hildebrand, Scatchard and Connor's fitting methodologies. The 1:1 stoichiometry of the host–guest complexation was confirmed by Job's continuous variation method. -- Highlights: • The malonohydrazide based fluorescent probe (7E,8E)-N1′,N>3′-bis(1-(2-hydroxyphenyl)ethylidene) malonohydrazide (receptor 5) was designed and synthesized. • The 1:1 stoichiometry of the host–guest relationship was realized from the Job's plot. • The stability constant was obtained by Benesi–Hildebrand, Scatchard and Connor methodologies.

  18. Rapid fluorescence determination of diquat herbicide in food grains using quantum dots as new reducing agent

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo-Carrion, Carolina; Simonet, Bartolome M. [Department of Analytical Chemistry, University of Cordoba, E-14071 Cordoba (Spain); Valcarcel, Miguel, E-mail: qa1meobj@uco.es [Department of Analytical Chemistry, University of Cordoba, E-14071 Cordoba (Spain)

    2011-04-29

    CdSe/ZnS QDs have demonstrated capacity to act as reducing agent in organic media such as acetonitrile and ethanol. By using fluorescence and Raman spectroscopy, it has been demonstrated that QDs reduce diquat herbicide to its monocation radical. The reaction is characterized to present a high reaction rate making possible to perform the reaction by simple filtration of the solution containing the herbicide through a QDs modified filter. The monocation radical presents a high fluorescence emission spectrum which was selected as the analytical signal to quantify the diquat herbicide. The method described here for the analysis of diquat herbicide in oat grains is simple and fast allowing the analysis of trace level of herbicide in only 6 min. The excellent sensitivity and reproducibility of the methods indicate that the reaction is favoured from both thermodynamic and kinetic point of view. The results presented open up the possibility to use QDs as redox agent. The sensitivity of the method expressed as detection limit was only of 0.01 mg kg{sup -1}.The lineal range was between 0.05 and 0.5 mg kg{sup -1}. The time of analysis per sample, including extraction, reaction and fluorescent measurement was only of 6 min.

  19. Determination of curcumin in biologically active supplements and food spices using a mesofluidic platform with fluorescence detection.

    Science.gov (United States)

    Petrova, Anastasiia; Dar'in, Dmitriy; Ivanov, Aleхander; Moskvin, Leonid; Ishimatsu, Ryoichi; Nakano, Koji; Imato, Toshihiko; Bulatov, Andrey

    2016-10-01

    A mesofluidic platform (MP) with fluorescence detection based on a stepwise injection analysis (SWIA) was used for the determination of curcumin in biologically active supplements and food spices. The main units of the MP are a mixing chamber (MC) and an optical channel with a quartz capillary inside. The MC provides rapid and complete mixing solutions by gas bubbling. The proposed method is based on the new rapid and sensitive reaction of curcumin with a fluorescence reagent - 4-(2,3,3-trimethyl-3H-indolium-1-yl)butane-1-sulfonate (TIBS). The fluorescence intensity of TIBS is greatly quenched in the presence of curcumin in an alkaline medium. The linear range was from 1 to 10µM of curcumin, and the limit of detection, calculated as 3σ of a blank test (n=5), was found to be 0.3µM. The sample throughput was 24h(-1). The proposed method was successfully applied for the determination of curcumin in biologically active supplements and samples of food spices. The obtained data were in good agreement with those measured by a HPLC-UV method.

  20. Determination of macromolecular exchange and PO2 in the microcirculation: a simple system for in vivo fluorescence and phosphorescence videomicroscopy

    Directory of Open Access Journals (Sweden)

    Torres L.N.

    2001-01-01

    Full Text Available We have developed a system with two epi-illumination sources, a DC-regulated lamp for transillumination and mechanical switches for rapid shift of illumination and detection of defined areas (250-750 µm² by fluorescence and phosphorescence videomicroscopy. The system permits investigation of standard microvascular parameters, vascular permeability as well as intra- and extravascular PO2 by phosphorescence quenching of Pd-meso-tetra (4-carboxyphenyl porphine (PORPH. A Pechan prism was used to position a defined region over the photomultiplier and TV camera. In order to validate the system for in vivo use, in vitro tests were performed with probes at concentrations that can be found in microvascular studies. Extensive in vitro evaluations were performed by filling glass capillaries with solutions of various concentrations of FITC-dextran (diluted in blood and in saline mixed with different amounts of PORPH. Fluorescence intensity and phosphorescence decay were determined for each mixture. FITC-dextran solutions without PORPH and PORPH solutions without FITC-dextran were used as references. Phosphorescence decay curves were relatively unaffected by the presence of FITC-dextran at all concentrations tested (0.1 µg/ml to 5 mg/ml. Likewise, fluorescence determinations were performed in the presence of PORPH (0.05 to 0.5 mg/ml. The system was successfully used to study macromolecular extravasation and PO2 in the rat mesentery circulation under controlled conditions and during ischemia-reperfusion.

  1. Uranium extraction by complexation with siderophores

    Science.gov (United States)

    Bahamonde Castro, Cristina

    One of the major concerns of energy production is the environmental impact associated with the extraction of natural resources. Nuclear energy fuel is obtained from uranium, an abundant and naturally occurring element in the environment, but the currently used techniques for uranium extraction leave either a significant fingerprint (open pit mines) or a chemical residue that alters the pH of the environment (acid or alkali leaching). It is therefore clear that a new and greener approach to uranium extraction is needed. Bioleaching is one potential alternative. In bioleaching, complexants naturally produced from fungi or bacteria may be used to extract the uranium. In the following research, the siderophore enterobactin, which is naturally produced by bacteria to extract and solubilize iron from the environment, is evaluated to determine its potential for complexing with uranium. To determine whether enterobactin could be used for uranium extraction, its acid dissociation and its binding strength with the metal of interest must be determined. Due to the complexity of working with radioactive materials, lanthanides were used as analogs for uranium. In addition, polyprotic acids were used as structural and chemical analogs for the siderophore during method development. To evaluate the acid dissociation of enterobactin and the subsequent binding constants with lanthanides, three different analytical techniques were studied including: potentiometric titration, UltraViolet Visible (UV-Vis) spectrophotometry and Isothermal Titration Calorimetry (ITC). After evaluation of three techniques, a combination of ITC and potentiometric titrations was deemed to be the most viable way for studying the siderophore of interest. The results obtained from these studies corroborate the ideal pH range for enterobactin complexation to the lanthanide of interest and pave the way for determining the strength of complexation relative to other naturally occurring metals. Ultimately, this

  2. Comparison of available measurements of the absolute air-fluorescence yield and determination of its global average value

    CERN Document Server

    Rosado, J; Arqueros, F

    2011-01-01

    Experimental results of the absolute air-fluorescence yield are given very often in different units (photons/MeV or photons/m) and for different wavelength intervals. In this work we present a comparison of available results normalized to its value in photons/MeV for the 337 nm band at 1013 hPa and 293 K. The conversion of photons/m to photons/MeV requires an accurate determination of the energy deposited by the electrons in the field of view of the experimental set-up. We have calculated the energy deposition for each experiment by means of a detailed Monte Carlo simulation and the results have been compared with those assumed or calculated by the authors. As a result, corrections to the reported fluorescence yields are proposed. These corrections improve the compatibility between measurements in such a way that a reliable average value with uncertainty at the level of 5% is obtained.

  3. Flow injection-chemical vapor generation atomic fluorescence spectrometry hyphenated system for organic mercury determination: A step forward

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, Valeria [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Biagi, Simona [National Research Council of Italy, C.N.R., Istituto per i Processi Chimico-Fisici - IPCF-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ghimenti, Silvia [University of Pisa, Department of Chemistry and Industrial Chemistry, Via Risorgimento 35, 56126 Pisa (Italy); Onor, Massimo; D' Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2011-11-15

    Monomethylmercury and ethylmercury were determined on line using flow injection-chemical vapor generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethylmercury were detected by atomic fluorescence spectrometry in an Ar/H{sub 2} miniaturized flame after sodium borohydride reduction to Hg{sup 0}, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H{sub 2} microflame was investigated. The behavior of inorganic mercury, monomethylmercury and ethylmercury and their cysteine-complexes was also studied by continuous flow-chemical vapor generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethylmercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethylmercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10{sup -5} mol L{sup -1}), thus allowing the organic/inorganic mercury speciation. The detection limits of the flow injection-chemical vapor generation atomic fluorescence spectrometry method were about 45 nmol L{sup -1} (as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 {mu}mol L{sup -1} were obtained. Recoveries of monomethylmercury and ethylmercury with respect to inorganic mercury were

  4. Uranium: biokinetics and toxicity; Biocinetique et toxicite de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Menetrier, F.; Renaud-Salis, V.; Flury-Herard, A

    2000-07-01

    This report was achieved as a part of a collaboration with the Fuel Cycle Direction. Its aim was to give the state of the art about: the behaviour of uranium in the human organism (biokinetics) after ingestion, its toxicity (mainly renal) and the current regulation about its incorporation. Both in the upstream and in the downstream of the fuel cycle, uranium remains, quantitatively, the first element in the cycle which is, at the present time, temporarily disposed or recycled. Such a considerable quantity of uranium sets the problem of its risk on the health. In the long term, the biosphere may be affected and consequently the public may ingest water or food contaminated with uranium. In this way, radiological and chemical toxicity risk may be activated. This report emphasizes: the necessity of confirming some experimental and epidemiological biokinetic data used or not in the ICRP models. Unsolved questions remain about the gastrointestinal absorption according to chemical form (valency state, mixtures...), mass and individual variations (age, disease) further a chronic ingestion of uranium. It is well established that uranium is mainly deposited in the skeleton and the kidney. But the skeleton kinetics following a chronic ingestion and especially in some diseases has to be more elucidated; the necessity of taking into account uranium at first as a chemical toxic, essentially in the kidney and determining the threshold of functional lesion. In this way, it is important to look for some specific markers; the problem of not considering chemical toxicity of uranium in the texts regulating its incorporation.

  5. Determination of Parathion-methyl in Vegetables by Fluorescent-Labeled Molecular Imprinted Polymer%Determination of Parathion-methyl in Vegetables by Fluorescent-Labeled Molecular Imprinted Polymer

    Institute of Scientific and Technical Information of China (English)

    孙倩; 姚倩倩; 孙琳; 周天舒; 聂冬霞; 施国跃; 金利通

    2011-01-01

    A novel sensor for the determination of parathion-methyl based on couple grafting of functional molecular imprinted polymers (MIPs) was fabricated which is developed by anchoring the MIP layer on surfaces of silica particles embedded CdSe quantum dots by surface imprinting technology. The synthesized molecular imprinted silica nanospheres (CdSe@SiO2@MIP) allow a high selectivity and sensitivity of parathion-methyl via fluorescence intensity decreasing when the MIP material rebinding the parathion-methyl molecule. Compared with the MIP fabri- cated in traditional method, the template of parathion-methyl was easier to remove from the CdSe@SiO2@MIP imprinted material. Under optimal conditions, the fluorescence intensity of parathion-methyl at the imprinted sensor was detected by spectrofluorophotometer. The relative fluorescence intensity of CdSe@SiO2@MIP decreased linearly with the increasing concentration of parathion-methyl ranging from 0.013 mg·kg^-1 to 2.63mg·kg^-1 with a detection limit (3σ) of 0.004 mg·kg^-1 (S/N=3), which is lower than the MIP in tradition. The imprinted film sensor was applied to detect parathion-methyl in vegetable samples without the interference of other organophosphate pesticides and showed a prosperous application in the field of food safety.

  6. Spectrophotometric Determination of Microamounts of Uranium previous Extraction with TBP-MIC; Determinacion Espectrofotometrica de Microcantidades de Uranio previa extraccin con Metilisobutilcetona-Fosfato de Tributilo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J.; Palomares Delgado, F.; Petrement, J.; Fernandez Cellini, R.

    1962-07-01

    Selective extraction of uranium in nitric acid medium with a mixture of Tbp-MIC (1:10) has been achieved. Aluminium nitrate was used as salting agent. Complexing agents were added in order to avoid extraction of impurities. Extraction conditions have been studied so that extraction is almost practically complete in a single run. (Author) 19 refs.

  7. Simultaneous extraction and preconcentration of uranium and thorium in aqueous samples by new modified mesoporous silica prior to inductively coupled plasma optical emission spectrometry determination.

    Science.gov (United States)

    Yousefi, Seyed Reza; Ahmadi, Seyed Javad; Shemirani, Farzaneh; Jamali, Mohammad Reza; Salavati-Niasari, Masoud

    2009-11-15

    A new synthesized modified mesoporous silica (MCM-41) using 5-nitro-2-furaldehyde (fural) was applied as an effective sorbent for the solid phase extraction of uranium(VI) and thorium(IV) ions from aqueous solution for the measurement by inductively coupled plasma optical emission spectrometry (ICP OES). The influences of some analytical parameters on the quantitative recoveries of the analyte ions were investigated in batch method. Under optimal conditions, the analyte ions were sorbed by the sorbent at pH 5.5 and then eluted with 1.0 mL of 1.0 mol L(-1) HNO(3). The preconcentration factor was 100 for a 100mL sample volume. The limits of detection (LOD) obtained for uranium(VI) and thorium(IV) were 0.3 microg L(-1). The maximum sorption capacity of the modified MCM-41 was found to be 47 and 49 mg g(-1) for uranium(VI) and thorium(IV), respectively. The sorbent exhibited good stability, reusability, high adsorption capacity and fast rate of equilibrium for sorption/desorption of uranium and thorium ions. The applicability of the synthesized sorbent was examined using CRM and real water samples.

  8. An analytical method to determine activity concentrations of uranium- and thorium-series radionuclides in outdoor air

    Energy Technology Data Exchange (ETDEWEB)

    Rozas, S.; Moja, M.; Alegria, N.; Idoeta, R.; Herranz, M. [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda Urquijo s/n, E-48013, Bilbao (Spain)

    2014-07-01

    Radon and its progeny in the outdoor air are one of the contributors to human exposure from natural sources. However, not only are their concentrations in the low layers of the atmosphere very low and affected by atmospheric mixing phenomena, some of these radionuclides have quite a low or very low half-life as well. These facts make the assessment of an independent activity concentration value for each of them difficult and as the existence of radioactive equilibrium in free air among the different radionuclides from the radioactive series cannot be considered, some approaches like the use of an established equilibrium factor are usually taken into account. Therefore, the objectives of this study are to characterize the outdoor air of Bilbao (Spain) in terms of natural radionuclides composition and to obtain the specific value of the equilibrium factor between radon and its progeny. To achieve these objectives a set of experimental steps have been carried out: aerosols and particles have been collected from the air using an aerosol sampling station with a nominal flow rate of 500 m{sup 3} h{sup -1} and, simultaneously, the Rn activity concentration was obtained by means of an automatic radon probe which provides values applying a pseudo-coincidence technique. Obtained particle filters were immediately measured by gamma-ray spectrometry and also one week and one month after the first measurement. After that, an analytical method, based on Bateman equations, has been used to obtain the activity concentrations of short-lived radionuclides in the sampled air from the values obtained in the early gamma-ray measurements. This analytical method has been previously used to determine the activity concentration of these radionuclides during a welding process and results have been published. As a result of this process, the air is characterized and the data needed to assess the equilibrium factor, by means of the equilibrium equivalent radon concentration, obtained. Achieved

  9. Uranium: A Dentist's perspective

    OpenAIRE

    Toor, R. S. S.; Brar, G. S.

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% – 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion repla...

  10. Chemical thermodynamics of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Grenthe, I.; Fuger, J.; Lemire, R.J.; Muller, A.B.; Nguyen-Trung Cregu, C.; Wanner, H.

    1992-01-01

    A comprehensive overview on the chemical thermodynamics of those elements that are of particular importance in the safety assessment of radioactive waste disposal systems is provided. This is the first volume in a series of critical reviews to be published on this subject. The book provides an extensive compilation of chemical thermodynamic data for uranium. A description of procedures for activity corrections and uncertainty estimates is given. A critical discussion of data needed for nuclear waste management assessments, including areas where significant gaps of knowledge exist is presented. A detailed inventory of chemical thermodynamic data for inorganic compounds and complexes of uranium is listed. Data and their uncertainty limits are recommended for 74 aqueous complexes and 199 solid and 31 gaseous compounds containing uranium, and on 52 aqueous and 17 solid auxiliary species containing no uranium. The data are internally consistent and compatible with the CODATA Key Values. The book contains a detailed discussion of procedures used for activity factor corrections in aqueous solution, as well as including methods for making uncertainty estimates. The recommended data have been prepared for use in environmental geochemistry. Containing contributions written by experts the chapters cover various subject areas such a s: oxide and hydroxide compounds and complexes, the uranium nitrides, the solid uranium nitrates and the arsenic-containing uranium compounds, uranates, procedures for consistent estimation of entropies, gaseous and solid uranium halides, gaseous uranium oxides, solid phosphorous-containing uranium compounds, alkali metal uranates, uncertainties, standards and conventions, aqueous complexes, uranium minerals dealing with solubility products and ionic strength corrections. The book is intended for nuclear research establishments and consulting firms dealing with uranium mining and nuclear waste disposal, as well as academic and research institutes.

  11. Determination of uranium isotopic composition and {sup 236}U content of soil samples and hot particles using inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F. [Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Central Department for Analytical Chemistry, Research Centre Juelich (Germany)

    2001-07-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The {sup 236}U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10{sup -4} and 10{sup -3} counts per atom were achieved for {sup 238}U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH{sup +}/U{sup +} was 1.2 x 10{sup -4} and 1.4 x 10{sup -4}, respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 {mu}g L{sup -1} NBS U-020 standard solution was 0.11% ({sup 238}U/{sup 235}U) and 1.4% ({sup 236}U/{sup 238}U) using a MicroMist nebulizer and 0.25% ({sup 235}U/{sup 238}U) and 1.9% ({sup 236}U/{sup 238}U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the {sup 236}U/{sup 238}U ratio ranged from 10{sup -5} to 10{sup -3}. Results obtained with ICP-MS, {alpha}- and {gamma}-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples. (orig.)

  12. Uranium Immobilization in Wetland Soils

    Science.gov (United States)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

  13. Uncertainty Evaluation on the Determination of Uranium Ores by Volumetry of Ammonium Vanadate%钒酸铵容量法测定岩石矿物中铀的不确定度评定

    Institute of Scientific and Technical Information of China (English)

    马立奎; 王垚; 罗媛媛; 黎金标; 朱乐杰

    2012-01-01

    Uncertainty evaluation on the criteria of "ferrous sulfate deoxidization / ammonium vanadate oxidation titrimetry to measure uranium" (EJ267. 2-84) issued by Ministry of Nuclear Industry was analyzed. The uncertainty brought by the method itself was obtained through the identification of uncertainty sources, quantification of uncertainty components and determination of uranium content by titration with calibrated ammonium vanadate solution. With the analytical study to uncertainty sources of entire process and components, and the application of statistical treatment based on scientific data, the combined standard uncertainty and expanded uncertainty about different levels of uranium content was reported.%根据核工业行业标准“硫酸亚铁还原/钒酸铵氧化滴定法测铀”(EJ267.2-84)进行不确定度评定.通过不确定度来源识别,不确定度分量的量化,并以标定好的钒酸铵溶液滴定铀质量分数,得出方法本身带来数据的不确定度.对整个过程的不确定度来源和大小进行分析研究,应用统计学基础对数据进行科学处理.报告出了不同铀质量分数的合成标准不确定度和扩展不确定度.

  14. PRODUCTION OF URANIUM

    Science.gov (United States)

    Ruehle, A.E.; Stevenson, J.W.

    1957-11-12

    An improved process is described for the magnesium reduction of UF/sub 4/ to produce uranium metal. In the past, there have been undesirable premature reactions between the Mg and the bomb liner or the UF/sub 4/ before the actual ignition of the bomb reaction. Since these premature reactions impair the yield of uranium metal, they have been inhibited by forming a protective film upon the particles of Mg by reacting it with hydrated uranium tetrafluoride, sodium bifluoride, uranyl fluoride, or uranium trioxide. This may be accomplished by adding about 0.5 to 2% of the additive to the bomb charge.

  15. METHOD OF ROLLING URANIUM

    Science.gov (United States)

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  16. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

    Full Text Available Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU, there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000: 215-220

  17. Accurate fast method with high chemical yield for determination of uranium isotopes ({sup 234}U, {sup 235}U, {sup 238}U) in granitic samples using alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guirguis, Laila A., E-mail: lailagurgus@yahoo.com; Farag, Nagdy M.; Salim, Adham K.

    2015-03-21

    The present study aims to use the α-spectroscopy at Nuclear Materials Authority (NMA) of Egypt. A radiochemical technique for analysis uranium isotopes was carried out for ten mineralized granitic samples together with the International standards RGU-1 (IAEA) and St{sub 4} (NMA). Several steps of sample preparation, radiochemical separation and source preparation were performed before analysis. Uranium was separated from sample matrix with 0.2 M TOPO in cyclohexane as an extracting agent with a chemical yield 98.95% then uranium was purified from lanthanides and actinides present with 0.2 M TOA in xylene as an extracting agent. The pure fraction was electrodeposited on a mirror-polished copper disc from buffer solution (NaHSO{sub 4}+H{sub 2}SO{sub 4}+NH{sub 4}OH). Rectangle pt-electrode with an anode-cathode distance of 2 cm was used. Current was 900 mA and the electrodeposition time reach up to 120 min. The achieved results show that the chemical yield ranged between 87.9±6.8 and 98±8.6. - Highlights: • Radiochemical technique for analysis uranium isotopes. • Alpha-particle spectrometry is performed after a radiochemical procedure. • Electrodeposition conditions for preparation of alpha uranium source. • Using {sup 232}U (t{sub 1/2}=70.6a, E{sub α}=5320.24 keV, intensity=69.1%) as an internal tracer makes it a highly reliable technique.

  18. Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Baoxia [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Huang, Yankai [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Xu; Hao, Yuanqiang [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Ding, Yujie [College of Biochemical Engineering, Anhui Polytechnic University, Wuhu 241000 (China); Wei, Wei; Wang, Qi [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Qu, Peng, E-mail: qupeng0212@163.com [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Xu, Maotian, E-mail: xumaotian@sqnc.edu.cn [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

    2016-03-17

    Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg{sup 2+} detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb{sup 3+} from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg{sup 2+} into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg{sup 2+}. As a kind of Hg{sup 2+} nanosensor, the probe exhibited excellent selectivity for Hg{sup 2+} and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg{sup 2+} in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg{sup 2+} was achieved based on time-resolved spectroscopy.

  19. Theoretical study of determining orientation and alignment of symmetric top molecule using laser-induced fluorescence

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    General expressions used for extracting the orientation and alignment parameters of a symmetric top molecule from laser-induced fluorescence (LIF) intensity are derived by employing the density matrix approach. The molecular orientation and alignment are described by molecular state multipoles. Excitation and detection are circularly and linearly polarized lights, respectively. In general cases, the LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors and the excitation-detection geometrical factors. It contains a population, ten orientation and fourteen alignment multipoles. The problem of how to extract the initial molecular state multipoles from the resolved LIF intensity is discussed.

  20. Selective Determination of tetrabromobisphenol A by liquid chromatography following intramolecular excimer-forming fluorescence derivatization with pyrene-labeling reagent

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, H.; Tsunetomo, S.; Todoroki, K.; Nohta, H.; Yamaguchi, M. [Fukuoka Univ. (Japan); Hayama, T. [Foundation for Kyushu Environmental and Occupational Health, Kurume (Japan); Kuroki, H. [Daiichi College of Pharmaceutical Sciences, Fukuoka (Japan)

    2004-09-15

    A large number of compounds have been used as flame-retardants to protect different products from catching fire, and one of the most widely used flameretardants is tetrabromobisphenol A (TBBPA). Trace amounts of TBBPA have been determined by gas chromatography (GC) with electron-capture detection or GC-mass spectrometry (MS) as reviewed in. Only a few liquid chromatographic (LC) methods have been reported. Recently, we developed highly selective and sensitive determination methods for polyamines and dicarboxylic acids based on intramolecular excimer-forming fluorescence derivatization using pyrene reagents. By the derivatization, the resulting polypyrene-labeled derivatives of polyamines and dicarboxylic acids provided intramolecular excimer fluorescence at the wavelength region of 440 - 520 nm, which was shifted markedly to the higher emission wavelengths as compared to the wavelengths of the pyrene reagent itself and monopyrene-labeled concomitants (360 - 420 nm). This chemistry allowed to selectively analyzing poly-functional compounds even in the complex samples containing monofunctional compounds. More recently, we have found that 4-(1-pyrene)butanoyl chloride (PBC) reacts with not only polyamines, but also phenol compounds such as bisphenols, and the obtained PBC derivatives form strong intramolecular excimers. The aim of this work was to develop an intramolecular excimer-forming derivatization method for fluorimetric determination of halogenated-bisphenols including TBBPA following their derivatization with PBC. The new method allows a highly sensitive and selective determination of tetrabromobisphenol A.

  1. Sequential extraction method for determination of Fe(II/III) and U(IV/VI) in suspensions of iron-bearing phyllosilicates and uranium.

    Science.gov (United States)

    Luan, Fubo; Burgos, William D

    2012-11-06

    Iron-bearing phyllosilicates strongly influence the redox state and mobility of uranium because of their limited hydraulic conductivity, high specific surface area, and redox reactivity. Standard extraction procedures cannot be accurately applied for the determination of clay-Fe(II/III) and U(IV/VI) in clay mineral-U suspensions such that advanced spectroscopic techniques are required. Instead, we developed and validated a sequential extraction method for determination of clay-Fe(II/III) and U(IV/VI) in clay-U suspensions. In our so-called "H(3)PO(4)-HF-H(2)SO(4) sequential extraction" method, H(3)PO(4)-H(2)SO(4) is used first to solubilize and remove U, and the remaining clay pellet is subject to HF-H(2)SO(4) digestion. Physical separation of U and clay eliminates valence cycling between U(IV/VI) and clay-Fe(II/III) that otherwise occurred in the extraction solutions and caused analytical discrepancies. We further developed an "automated anoxic KPA" method to measure soluble U(VI) and total U (calculate U(IV) by difference) and modified the conventional HF-H(2)SO(4) digestion method to eliminate a series of time-consuming weighing steps. We measured the kinetics of uraninite oxidation by nontronite using this sequential extraction method and anoxic KPA method and measured a stoichiometric ratio of 2.19 ± 0.05 mol clay-Fe(II) produced per mol U(VI) produced (theoretical value of 2.0). We found that we were able to recover 98.0-98.5% of the clay Fe and 98.1-98.5% of the U through the sequential extractions. Compared to the theoretical stoichiometric ratio of 2.0, the parallel extractions of 0.5 M HCl for clay-Fe(II) and 1 M NaHCO(3) for U(VI) leached two-times more Fe(II) than U(VI). The parallel extractions of HF-H(2)SO(4) for clay Fe(II) and 1 M NaHCO(3) for U(VI) leached six-times more Fe(II) than U(VI).

  2. Ultra-trace determination of beryllium in occupational hygiene samples by ammonium bifluoride extraction and fluorescence detection using hydroxybenzoquinoline sulfonate.

    Science.gov (United States)

    Ashley, Kevin; Agrawal, Anoop; Cronin, John; Tonazzi, Juan; McCleskey, T Mark; Burrell, Anthony K; Ehler, Deborah S

    2007-02-19

    A highly sensitive molecular fluorescence method for measuring ultra-trace levels of beryllium has been previously described. The method entails extraction of beryllium workplace samples by 1% ammonium bifluoride (NH(4)HF(2), aqueous), followed by fluorescence detection using hydroxybenzoquinoline sulfonate (HBQS). In this work, modification of the existing procedure resulted in a significant improvement in detection power, thereby enabling ultra-trace determination of beryllium in air filter and surface wipe samples. Such low detection limits may be necessary in view of expected decreases in applicable occupational exposure limits (OELs) for beryllium. Attributes of the modified NH(4)HF(2) extraction/HBQS fluorescence method include method detection limits (MDLs) of <0.8 ng to approximately 2 ng Be per sample (depending on the fluorometer used), quantitative recoveries from beryllium oxide, a dynamic range of several orders of magnitude, and freedom from interferences. Other key advantages of the technique are field portability, relatively low cost, and high sample throughput. The method performance compares favorably with that of inductively coupled plasma-mass spectrometry (ICP-MS).

  3. Ultra-trace determination of beryllium in occupational hygiene samples by ammonium bifluoride extraction and fluorescence detection using hydroxybenzoquinoline sulfonate

    Energy Technology Data Exchange (ETDEWEB)

    Ashley, Kevin [U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, M.S. R-7, Cincinnati, OH 45226-1998 (United States)]. E-mail: kashley@cdc.gov; Agrawal, Anoop [Berylliant, Inc., 4541 E. Fort Lowell Road, Tucson, AZ 85712 (United States); Cronin, John [Berylliant, Inc., 4541 E. Fort Lowell Road, Tucson, AZ 85712 (United States); Tonazzi, Juan [Berylliant, Inc., 4541 E. Fort Lowell Road, Tucson, AZ 85712 (United States); McCleskey, T. Mark [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Burrell, Anthony K. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Ehler, Deborah S. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)

    2007-02-19

    A highly sensitive molecular fluorescence method for measuring ultra-trace levels of beryllium has been previously described. The method entails extraction of beryllium workplace samples by 1% ammonium bifluoride (NH{sub 4}HF{sub 2}, aqueous), followed by fluorescence detection using hydroxybenzoquinoline sulfonate (HBQS). In this work, modification of the existing procedure resulted in a significant improvement in detection power, thereby enabling ultra-trace determination of beryllium in air filter and surface wipe samples. Such low detection limits may be necessary in view of expected decreases in applicable occupational exposure limits (OELs) for beryllium. Attributes of the modified NH{sub 4}HF{sub 2} extraction/HBQS fluorescence method include method detection limits (MDLs) of <0.8 ng to {approx}2 ng Be per sample (depending on the fluorometer used), quantitative recoveries from beryllium oxide, a dynamic range of several orders of magnitude, and freedom from interferences. Other key advantages of the technique are field portability, relatively low cost, and high sample throughput. The method performance compares favorably with that of inductively coupled plasma-mass spectrometry (ICP-MS)

  4. Correlation of tryptophan fluorescence intensity decay parameters with sup 1 H NMR-determined rotamer conformations: (tryptophan sup 2 )oxytocin

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J.B.A.; Schwartz, G.P.; Laws, W.R. (Mount Sinai, New York, NY (United States)); Wyssbrod, H.R.; Porter, R.A. (Univ. of Louisville, KY (United States)); Michaels, C.A. (Swarthmore Coll., PA (United States))

    1992-02-18

    While the fluorescence decay kinetics of tyrosine model compounds can be explained in terms of heterogeneity derived from the three ground-state {chi}{sup 1} rotamers, a similar correlation has yet to be directly observed for a tryptophan residue. In addition, the asymmetric indole ring might also lead to heterogeneity from {chi}{sup 2} rotations. In this paper, the time-resolved and steady-state fluorescence properties of (tryptophan{sup 2})oxytocin at pH 3 are presented and compared with {sup 1}H NMR results. According to the unrestricted analyses of individual fluorescence decay curves taken as a function of emission wavelength-independent decay constants, only three exponential terms are required. In addition, the preexponential weighting factors (amplitudes) have the same relative relationship (weights) as the {sup 1}H NMR-determined {chi}{sup 1} rotamer populations of the indole side chain. {sup 15}N was used in heteronuclear coupling experiments to confirm the rotamer assignments. Inclusion of a linked function restricting the decay amplitudes to the {chi}{sup 1} rotamer populations in the individual decay curve analyses and in the global analysis confirms this correlation. According to qualitative nuclear Overhauser data, there are two {chi}{sup 2} populations.

  5. Determining the fate of fluorescent quantum dots on surface of engineered budding S. cerevisiae cell molecular landscape.

    Science.gov (United States)

    Chouhan, Raghuraj S; Qureshi, Anjum; Niazi, Javed H

    2015-07-15

    In this study, we surface engineered living S. cerevisiae cells by decorating quantum dots (QDs) and traced the fate of QDs on molecular landscape of single mother cell through several generation times (progeny cells). The fate of QDs on cell-surface was tracked through the cellular division events using confocal microscopy and fluorescence emission profiles. The extent of cell-surface QDs distribution among the offspring was determined as the mother cell divides into daughter cells. Fluorescence emission from QDs on progeny cells was persistent through the second-generation time (~240min) until all of the progeny cells lost their cell-bound QDs during the third generation time (~360min). The surface engineered yeast cells were unaffected by the QDs present on their molecular landscapes and retained their normal cellular growth, architecture and metabolic activities as confirmed by their viability, scanning electron microscopy (SEM) examinations and cytotoxicity tests, respectively. Our results demonstrated that QDs on mother cell landscape tend to distribute among its progeny cells that accompanied with concomitant reduction in QDs' fluorescence, which can be quantified. We suggest that surface engineered cells with QDs will enable investigating the cellular behavior and monitoring cell growth patterns as nanobiosensors for screening of drugs/chemicals at single cell level with fewer side effects. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Method for determining microamounts of uranium in solutions from copper ores, by liquid-liquid extraction and spectrophotometry with arsenazo III.; Metodo para determinar microcantidades de uranio en disoluciones de minerales de cobre, por extraccion liquido-liquido y espectrofotometria con arsenazo III

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, B.

    1972-07-01

    A spectrophotometric method is described for determining small amounts of uranium in aqueous solutions from copper ores. Uranium is quantitatively separated in a single extraction by a solution of tri-n-octylphosphine oxide in benzene, using ethylendiaminetetracetic acid and sodium fluoride as complexing agents, for improving the selectivity of the procedure. An aliquot of the extract is diluted with a hydrocolloidal solution of arsenazo III. Optical density is measured at 650 nm. (Author) 3 refs.

  7. [Determination of major elements in soil from cancer village by X-ray fluorescence spectrometry].

    Science.gov (United States)

    Wei, Zhen-Lin; Li, He; Rui, Yu-Kui

    2008-11-01

    Many social problems arise from environmental pollution, cancer village is one of the many important problems caused by pollution. The authors selected a typical cancer village where 80-100 people died of cancer in the last five years, but there are only a total of 1 200 people in this village. The authors sampled soils from crops-planted areas and detected the major elements by X-ray fluorescence spectrometry. The results showed that the contents of SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 in soil of this village were 66.05%, 0.66%, 11.37%, 3.93%, 0.075%, 1.97%, 5.47%, 1.90%, 2.11% and 0.20% respectively; with the precision being +/- 0.20%, +/- 0.005%, +/- 0.10%, +/- 0.10%, +/- 0.005%, +/- 0.05%, +/- 0.04%, +/- 0.08%, +/- 0.02% and +/- 0.005% respectively, which showed that X-ray fluorescence spectrometry is a good method.

  8. Potential application of synchronous fluorescence spectroscopy to determine benzo[a]pyrene in soil extracts

    Energy Technology Data Exchange (ETDEWEB)

    Hua Guoxiong [School of Biology, Institute for Research on the Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, NE1 7RU (United Kingdom); Killham, Ken [Department of Plant and Soil Science, Cruickshank Building, University of Aberdeen, AB24 3UU (United Kingdom); Singleton, Ian [School of Biology, Institute for Research on the Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, NE1 7RU (United Kingdom)]. E-mail: ian.singleton@ncl.ac.uk

    2006-01-15

    Benzo[a]pyrene (BaP) is a significant environmental pollutant and rapid, accurate methods to quantify this compound in soil for both research and environmental investigation purposes are required. In this work, solvent extracts from five contrasting soils spiked with four different polycyclic aromatic hydrocarbons (PAHs) were rapidly analysed by using a synchronous fluorescence spectroscopy (SFS) method. The SFS method was validated using HPLC with ultraviolet detection. A good correlation for the quantification of BaP in soil extracts by the two methods was observed. The detection limit of the SFS method was 1.6 x 10{sup -9} g/ml in CTAB micellar medium (7.8 mmol/l). The work demonstrates that SFS has potential as a sensitive, accurate, rapid, simple and economic methodology and an efficient alternative to HPLC for fast confirmation and quantification of BaP in complex soil extracts. - Synchronous fluorescence spectroscopy has potential as a method for confirmation of benzo[a]pyrene in soil extracts.

  9. Nanoparticle-based, organic receptor coupled fluorescent chemosensors for the determination of phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Navneet, E-mail: navneetkaur@pu.ac.in [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Kaur, Simanpreet; Kaur, Amanpreet [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Saluja, Preeti; Sharma, Hemant [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India); Saini, Anu; Dhariwal, Nisha [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Singh, Ajnesh; Singh, Narinder [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India)

    2014-01-15

    The sensors have been developed using silver nanoparticles coated with organic ligands and are fully characterized with spectroscopic methods. The energy-dispersive X-ray (EDX) analysis revealed the presence of organic receptors on the surface of metal nanoparticles. These chemosensors were tested against a range of biological and environmentally relevant cations in the HEPES buffered DMSO/H{sub 2}O (8:2, v/v) solvent system. The fluorescence intensity of these chemosensors was quenched upon coordination with open shell metal ions such as Cu{sup 2+}/Fe{sup 3+}. Anion recognition properties of the corresponding metal complexes have been studied and the original fluorescence intensity of sensors was restored upon addition of phosphate (0–20 µM). Thus, a highly selective chemosensor has been devised for the micromolar estimation of phosphate in semi-aqueous medium. -- Highlights: • The silver nanoparticles have been decorated with organic receptors for chemosensor applications. • The sensor properties are developed for the estimation of phosphate anion. • Thus the sensor relies on the cation displacement assay. • The phosphate sensing event displays the “ON–OFF–ON” mode of switching in sensor.

  10. Applications of X-ray fluorescence holography to determine local lattice distortions

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Kouichi, E-mail: khayashi@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Happo, Naohisa [Graduate School of Information Sciences, Hiroshima City University, Hiroshima 731-3194 (Japan); Hosokawa, Shinya [Department of Physics, Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan)

    2014-08-15

    Highlights: • We summarized topics of X-ray fluorescence holography focused on the local lattice distortions. • We found details of behaviors of nearest neighbor atoms around dopants. • We found the average distributions of the atoms at the individual sites in mixed crystals. • Distorted and undistorted sires sometimes coexist in a same mixed crystal. - Abstract: X-ray fluorescence holography (XFH) is a method for investigating atomic order up to the medium ranges, and can provide 3D atomic images around specific elements within a radius of nm order. In addition to these characteristics, XFH is sensitive to positional fluctuations of atoms, and therefore it is useful for characterizing the local lattice distortions around specific elements. We have applied XFH to dopants and mixed crystals. We found interesting features in local lattice distortions, such as the displacements of first-neighbor atoms around dopants, far-sighted views of the atomistic fluctuations in mixed crystals, and the coexistence of distorted/undistorted sites in the same material.