WorldWideScience

Sample records for bulk speciation methods

  1. Complementary arsenic speciation methods: A review

    Energy Technology Data Exchange (ETDEWEB)

    Nearing, Michelle M., E-mail: michelle.nearing@rmc.ca; Koch, Iris, E-mail: koch-i@rmc.ca; Reimer, Kenneth J., E-mail: reimer-k@rmc.ca

    2014-09-01

    The toxicity of arsenic greatly depends on its chemical form and oxidation state (speciation) and therefore accurate determination of arsenic speciation is a crucial step in understanding its chemistry and potential risk. High performance liquid chromatography with inductively coupled mass spectrometry (HPLC–ICP-MS) is the most common analysis used for arsenic speciation but it has two major limitations: it relies on an extraction step (usually from a solid sample) that can be incomplete or alter the arsenic compounds; and it provides no structural information, relying on matching sample peaks to standard peaks. The use of additional analytical methods in a complementary manner introduces the ability to address these disadvantages. The use of X-ray absorption spectroscopy (XAS) with HPLC–ICP-MS can be used to identify compounds not extracted for HPLC–ICP-MS and provide minimal processing steps for solid state analysis that may help preserve labile compounds such as those containing arsenic-sulfur bonds, which can degrade under chromatographic conditions. On the other hand, HPLC–ICP-MS is essential in confirming organoarsenic compounds with similar white line energies seen by using XAS, and identifying trace arsenic compounds that are too low to be detected by XAS. The complementary use of electrospray mass spectrometry (ESI–MS) with HPLC–ICP-MS provides confirmation of arsenic compounds identified during the HPLC–ICP-MS analysis, identification of unknown compounds observed during the HPLC–ICP-MS analysis and further resolves HPLC–ICP-MS by identifying co-eluting compounds. In the complementary use of HPLC–ICP-MS and ESI–MS, HPLC–ICP-MS helps to focus the ESI–MS selection of ions. Numerous studies have shown that the information obtained from HPLC–ICP-MS analysis can be greatly enhanced by complementary approaches. - Highlights: • HPLC–ICP-MS is the most common method used for arsenic speciation. • HPLC limitations include

  2. Complementary arsenic speciation methods: A review

    International Nuclear Information System (INIS)

    The toxicity of arsenic greatly depends on its chemical form and oxidation state (speciation) and therefore accurate determination of arsenic speciation is a crucial step in understanding its chemistry and potential risk. High performance liquid chromatography with inductively coupled mass spectrometry (HPLC–ICP-MS) is the most common analysis used for arsenic speciation but it has two major limitations: it relies on an extraction step (usually from a solid sample) that can be incomplete or alter the arsenic compounds; and it provides no structural information, relying on matching sample peaks to standard peaks. The use of additional analytical methods in a complementary manner introduces the ability to address these disadvantages. The use of X-ray absorption spectroscopy (XAS) with HPLC–ICP-MS can be used to identify compounds not extracted for HPLC–ICP-MS and provide minimal processing steps for solid state analysis that may help preserve labile compounds such as those containing arsenic-sulfur bonds, which can degrade under chromatographic conditions. On the other hand, HPLC–ICP-MS is essential in confirming organoarsenic compounds with similar white line energies seen by using XAS, and identifying trace arsenic compounds that are too low to be detected by XAS. The complementary use of electrospray mass spectrometry (ESI–MS) with HPLC–ICP-MS provides confirmation of arsenic compounds identified during the HPLC–ICP-MS analysis, identification of unknown compounds observed during the HPLC–ICP-MS analysis and further resolves HPLC–ICP-MS by identifying co-eluting compounds. In the complementary use of HPLC–ICP-MS and ESI–MS, HPLC–ICP-MS helps to focus the ESI–MS selection of ions. Numerous studies have shown that the information obtained from HPLC–ICP-MS analysis can be greatly enhanced by complementary approaches. - Highlights: • HPLC–ICP-MS is the most common method used for arsenic speciation. • HPLC limitations include

  3. Complementary arsenic speciation methods: A review

    Science.gov (United States)

    Nearing, Michelle M.; Koch, Iris; Reimer, Kenneth J.

    2014-09-01

    The toxicity of arsenic greatly depends on its chemical form and oxidation state (speciation) and therefore accurate determination of arsenic speciation is a crucial step in understanding its chemistry and potential risk. High performance liquid chromatography with inductively coupled mass spectrometry (HPLC-ICP-MS) is the most common analysis used for arsenic speciation but it has two major limitations: it relies on an extraction step (usually from a solid sample) that can be incomplete or alter the arsenic compounds; and it provides no structural information, relying on matching sample peaks to standard peaks. The use of additional analytical methods in a complementary manner introduces the ability to address these disadvantages. The use of X-ray absorption spectroscopy (XAS) with HPLC-ICP-MS can be used to identify compounds not extracted for HPLC-ICP-MS and provide minimal processing steps for solid state analysis that may help preserve labile compounds such as those containing arsenicsbnd sulfur bonds, which can degrade under chromatographic conditions. On the other hand, HPLC-ICP-MS is essential in confirming organoarsenic compounds with similar white line energies seen by using XAS, and identifying trace arsenic compounds that are too low to be detected by XAS. The complementary use of electrospray mass spectrometry (ESI-MS) with HPLC-ICP-MS provides confirmation of arsenic compounds identified during the HPLC-ICP-MS analysis, identification of unknown compounds observed during the HPLC-ICP-MS analysis and further resolves HPLC-ICP-MS by identifying co-eluting compounds. In the complementary use of HPLC-ICP-MS and ESI-MS, HPLC-ICP-MS helps to focus the ESI-MS selection of ions. Numerous studies have shown that the information obtained from HPLC-ICP-MS analysis can be greatly enhanced by complementary approaches.

  4. Methods for macro concentration speciation (>106 M)

    International Nuclear Information System (INIS)

    The range of topics covered by the term 'speciation' varies from the determination of isotopic composition, through whether an element or nuclide is present and under which form, to the full identification of the molecular compound present or the isolation of species. Therefore, it is quite understandable that a rather large range of techniques may be applicable for speciation purposes and that none may be sufficient by itself to cover all purposes. We tried in this report to review on technologies available for speciation purposes in nuclear fuel cycle activities and to provide a reference document to guide researchers in choosing the most useful technique for his purposes by summarizing their characteristics. Particular attention was given to highlight the advantages and disadvantages/limitations of a given technique as well as, when suitable, expected or necessary future improvements. It was also attempted to indicate a 'recommended' application field, though this was not an easy task. In the present part, we concentrate on techniques available for macro concentration speciation with an arbitrary limit fixed around 10-6 M. However, one should be aware that some of the techniques discussed in the present may be also applicable for lower concentration (overlap with over Partim. of the whole report) and vice-versa. Then, we consider that the scope of the present can only be achieved considering the whole parts discussed at the OECD/NEA Workshop on evaluation of speciation technology held in October 1999 at JAERI/Tokai-mura. (author)

  5. Method for chromium analysis and speciation

    Energy Technology Data Exchange (ETDEWEB)

    Aiken, Abigail M.; Peyton, Brent M.; Apel, William A.; Petersen, James N.

    2004-11-02

    A method of detecting a metal in a sample comprising a plurality of metal is disclosed. The method comprises providing the sample comprising a metal to be detected. The sample is added to a reagent solution comprising an enzyme and a substrate, where the enzyme is inhibited by the metal to be detected. An array of chelating agents is used to eliminate the inhibitory effects of additional metals in the sample. An enzymatic activity in the sample is determined and compared to an enzymatic activity in a control solution to detect the metal to be detected. A method of determining a concentration of the metal in the sample is also disclosed. A method of detecting a valence state of a metal is also disclosed.

  6. Evaluation of mercury speciation by EPA (Draft) Method 29

    Energy Technology Data Exchange (ETDEWEB)

    Laudal, D.L.; Heidt, M.K. [Energy & Environmental Research Center, Grand Forks, ND (United States); Nott, B. [Electric Power Research Institute, Palo Alto, CA (United States)

    1995-11-01

    The 1990 Clean Air Act Amendments require that the U.S. Environmental protection Agency (EPA) assess the health risks associated with mercury emissions. Also, the law requires a separate assessment of health risks posed by the emission of 189 tract chemicals (including mercury) for electric utility steam-generating units. In order to conduct a meaningful assessment of health and environmental effects, we must have, among other things, a reliable and accurate method to measure mercury emissions. In addition, the rate of mercury deposition and the type of control strategies used may depend upon the type of mercury emitted (i.e., whether it is in the oxidized or elemental form). It has been speculated that EPA (Draft) Method 29 can speciate mercury by selective absorption; however, this claim has yet to be proven. The Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE) have contracted with the Energy & Environmental Research Center (EERC) at University of North Dakota to evaluate EPA (Draft) Method 29 at the pilot-scale level. The objective of the work is to determine whether EPA (Draft) Method 29 can reliably quantify and speciate mercury in the flue gas from coal-fired boilers.

  7. Arsenic extraction and speciation in plants: Method comparison and development.

    Science.gov (United States)

    Zhao, Di; Li, Hong-Bo; Xu, Jia-Yi; Luo, Jun; Ma, Lena Qiying

    2015-08-01

    We compared four methods to extract arsenic (As) from three different plants containing different As levels for As speciation with the goal of developing a more efficient method, i.e., As-hyperaccumulator Pteris vittata at 459-7714mgkg(-1), rice seedling at 53.4-574mgkg(-1), and tobacco leaf at 0.32-0.35mgkg(-1). The four methods included heating with dilute HNO3, and sonication with phosphate buffered solution, methanol/water, and ethanol/water, with As being analyzed using high-performance liquid chromatography coupled with inductively-coupled plasma mass spectrometry (HPLC-ICP-MS). Among the four methods, the ethanol/water method produced the most satisfactory extraction efficiency (~80% for the roots and >85% for the fronds) without changing As species based on P. vittata. The lower extraction efficiency from P. vittata roots was attributed to its dominance by arsenate (82%) while arsenite dominated in the fronds (89%). The ethanol/water method used sample:solution ratio of 1:200 (0.05g:10mL) with 50% ethanol and 2h sonication. Based on different extraction times (0.5-2h), ethanol concentrations (25-100%) and sample:solution ratios (1:50-1:300), the optimized ethanol/water method used less ethanol (25%) and time (0.5h for the fronds and 2h for the roots). Satisfactory extraction was also obtained for tobacco leaf (78-92%) and rice seedlings (~70%) using the optimized method, which was better than the other three methods. Based on satisfactory extraction efficiency with little change in As species during extraction from three plants containing different As levels, the optimized method has the potential to be used for As speciation in other plants. PMID:25863504

  8. A novel colorimetric method for field arsenic speciation analysis

    Institute of Scientific and Technical Information of China (English)

    Shan Hu; Jinsuo Lu; Chuanyong Jing

    2012-01-01

    Accurate on-site determination of arsenic (As) concentration as well as its speciation presents a great environmental challenge especially to developing countries.To meet the need of routine field monitoring,we developed a rapid colorimetric method with a wide dynamic detection range and high precision.The novel application of KMnO4 and CH4N2S as effective As(Ⅲ) oxidant and As(Ⅴ) reductant,respectively,in the formation of molybdenum blue complexes enabled the differentiation of As(Ⅲ) and As(Ⅴ).The detection limit of the method was 8 μg/L with a linear range (R2 =0.998) of four orders of magnitude in total As concentrations.The As speciation in groundwater samples determined with the colorimetric method in the field were consistent with the results using the high performance liquid chromatography atomic fluorescence spectrometry,as evidenced by a linear correlation in paired analysis with a slope of 0.9990-0.9997 (p < 0,0001,n =28).The recovery of 96%-116% for total As,85%-122% for As(Ⅲ),and 88%-127% for As(Ⅴ) were achieved for groundwater samples with a total As concentration range 100-800 μg/L,The colorimetric result showed that 3.61 g/L As(Ⅲ) existed as the only As species in a real industrial wastewater,which was in good agreement with the HPLC-AFS result of 3.56 g/L As(Ⅲ),No interference with the color development was observed in the presence of sulfate,phosphate,silicate,humic acid,and heavy metals from complex water matrix.This accurate,sensitive,and easy-to-use method is especially suitable for field As determination.

  9. Field Deployable Method for Arsenic Speciation in Water.

    Science.gov (United States)

    Voice, Thomas C; Flores Del Pino, Lisveth V; Havezov, Ivan; Long, David T

    2011-01-01

    Contamination of drinking water supplies by arsenic is a world-wide problem. Total arsenic measurements are commonly used to investigate and regulate arsenic in water, but it is well understood that arsenic occurs in several chemical forms, and these exhibit different toxicities. It is problematic to use laboratory-based speciation techniques to assess exposure as it has been suggested that the distribution of species is not stable during transport in some types of samples. A method was developed in this study for the on-site speciation of the most toxic dissolved arsenic species: As (III), As (V), monomethylarsonic acid (MMA) and dimethylarsenic acid (DMA). Development criteria included ease of use under field conditions, applicable at levels of concern for drinking water, and analytical performance.The approach is based on selective retention of arsenic species on specific ion-exchange chromatography cartridges followed by selective elution and quantification using graphite furnace atomic absorption spectroscopy. Water samples can be delivered to a set of three cartridges using either syringes or peristaltic pumps. Species distribution is stable at this point, and the cartridges can be transported to the laboratory for elution and quantitative analysis. A set of ten replicate spiked samples of each compound, having concentrations between 1 and 60 µg/L, were analyzed. Arsenic recoveries ranged from 78-112 % and relative standard deviations were generally below 10%. Resolution between species was shown to be outstanding, with the only limitation being that the capacity for As (V) was limited to approximately 50 µg/L. This could be easily remedied by changes in either cartridge design, or the extraction procedure. Recoveries were similar for two spiked hard groundwater samples indicating that dissolved minerals are not likely to be problematic. These results suggest that this methodology can be use for analysis of the four primary arsenic species of concern in

  10. On methods of estimating cosmological bulk flows

    CERN Document Server

    Nusser, Adi

    2015-01-01

    We explore similarities and differences between several estimators of the cosmological bulk flow, $\\bf B$, from the observed radial peculiar velocities of galaxies. A distinction is made between two theoretical definitions of $\\bf B$ as a dipole moment of the velocity field weighted by a radial window function. One definition involves the three dimensional (3D) peculiar velocity, while the other is based on its radial component alone. Different methods attempt at inferring $\\bf B$ for either of these definitions which coincide only for a constant velocity field. We focus on the Wiener Filtering (WF, Hoffman et al. 2015) and the Constrained Minimum Variance (CMV,Feldman et al. 2010) methodologies. Both methodologies require a prior expressed in terms of the radial velocity correlation function. Hoffman et al. compute $\\bf B$ in Top-Hat windows from a WF realization of the 3D peculiar velocity field. Feldman et al. infer $\\bf B$ directly from the observed velocities for the second definition of $\\bf B$. The WF ...

  11. On methods of estimating cosmological bulk flows

    Science.gov (United States)

    Nusser, Adi

    2016-01-01

    We explore similarities and differences between several estimators of the cosmological bulk flow, B, from the observed radial peculiar velocities of galaxies. A distinction is made between two theoretical definitions of B as a dipole moment of the velocity field weighted by a radial window function. One definition involves the three-dimensional (3D) peculiar velocity, while the other is based on its radial component alone. Different methods attempt at inferring B for either of these definitions which coincide only for the case of a velocity field which is constant in space. We focus on the Wiener Filtering (WF) and the Constrained Minimum Variance (CMV) methodologies. Both methodologies require a prior expressed in terms of the radial velocity correlation function. Hoffman et al. compute B in Top-Hat windows from a WF realization of the 3D peculiar velocity field. Feldman et al. infer B directly from the observed velocities for the second definition of B. The WF methodology could easily be adapted to the second definition, in which case it will be equivalent to the CMV with the exception of the imposed constraint. For a prior with vanishing correlations or very noisy data, CMV reproduces the standard Maximum Likelihood estimation for B of the entire sample independent of the radial weighting function. Therefore, this estimator is likely more susceptible to observational biases that could be present in measurements of distant galaxies. Finally, two additional estimators are proposed.

  12. A speciation solver for cement paste modeling and the semismooth Newton method

    International Nuclear Information System (INIS)

    The mineral assemblage of a cement paste may vary considerably with its environment. In addition, the water content of a cement paste is relatively low and the ionic strength of the interstitial solution is often high. These conditions are extreme conditions with respect to the common assumptions made in speciation problem. Furthermore the common trial and error algorithm to find the phase assemblage does not provide any guarantee of convergence. We propose a speciation solver based on a semismooth Newton method adapted to the thermodynamic modeling of cement paste. The strong theoretical properties associated with these methods offer practical advantages. Results of numerical experiments indicate that the algorithm is reliable, robust, and efficient

  13. Carbon nanotubes grown on bulk materials and methods for fabrication

    Science.gov (United States)

    Menchhofer, Paul A.; Montgomery, Frederick C.; Baker, Frederick S.

    2011-11-08

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  14. Fabrication of bulk metallic glasses by centrifugal casting method

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2007-01-01

    Full Text Available Purpose: The aim of the present work is characterization of the centrifugal casting method, apparatus andproduced amorphous materials, which are also known as bulk metallic glassesDesign/methodology/approach: The studied centrifugal casting system consists of two main parts: castingapparatus and injection system of molten alloy. The described centrifugal casting method was presented bypreparing a casting apparatus “CentriCast – 5”. The apparatus includes a cylindrical copper mold, which isrotated by a motor. The transmission allows to changing the speed of rotating mold.Findings: Bulk metallic glasses are a novel class of engineering materials, which exhibit excelent mechanical,thermal, magnetic and corrosion properties. Centrifugal casting is a useful method to produce bulk amorphousmaterials in form of rings, tubes or cylindrical parts. Presented centrifugal casting method and casting apparatushas been prepared to fabricate the samples of bulk metallic glass in form of rings with an outer diameter of 25mm and controlled thicknesses by changing the weight of the molten alloy.Research limitations/implications: Studied centrifugal casting method and casting apparatus has beenprepared to fabricate the samples of bulk metallic glass. For future research a characterization of microstructureand properties of prepared material will be performed.Practical implications: The centrifugal casting is a useful process to produce bulk amorphous materials in formof rings, tubes or graded amorphous matrix composites. It seems to be a very simple method, which allows toobtain BMG materials.Originality/value: The centrifugal casting method allows to produce bulk amorphous rings with thicknessabove 1-mm.

  15. Development and application of laserspectroscopic methods for the direct speciation of aquatic actinides

    International Nuclear Information System (INIS)

    The presented laserspectroscopic methods for the speciation of actinides in aquatic system, for the quantification and characterisation of colloids are important tools for the investigation of the migration of nuclides in the geosphere. The laserinduced photoacoustic spectroscopy is presented as a method of photothermal absorption spectroscopy. It can be applied for the highly sensitive speciation of the actinides in most of the geochemical relevant oxidation phases. Other photothermal methods, such as the ''Thermal-Lensing Spectroscopy'' or the ''Photothermal-Deflection Spectroscopy'' have comparable or even higher sensitivities. However, they also reveal some disadvantages due to the worse compensation possibilities of the underground in natural groundwater. These methods have been tested at the institute for radiochemistry (IRCh) and are planned to be realised as well in the INE. (orig.)

  16. Advanced tensile testing methods for bulk superconductors at cryogenic temperatures

    International Nuclear Information System (INIS)

    Tensile tests of bulk high Tc superconductors at room temperature have been generally performed by gluing the bulk specimens to Al-alloy rods. Because of the difference in the coefficient of thermal expansion, thermal stresses were induced at cryogenic temperatures especially near the interface between the specimen and the rods. In this study, tensile testing methods with minimized effect of the thermal stress were tried by using specimens cut from Dy-Ba-Cu-O superconductors. These were: (1) The rod material of Al-alloy was replaced with Ti-alloy, which has the coefficient close to the bulk. (2) The interlayer made of the identical bulk superconductor was inserted between the specimen and the Ti-alloy rod. The nominal tensile strength at the liquid nitrogen temperature (LNT) of the specimen glued to the Ti-alloy rods was significantly higher than that glued to the Al-alloy rods. The application of the interlayers increased the strength significantly. The FEM analysis showed that the thermal tensile stress component in the direction of loading axis within the specimen at LNT is markedly reduced by the method (1) and substantially eliminated in the method (2)

  17. Comparison of three molecular methods for the detection and speciation of Plasmodium vivax and Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Price Ric N

    2007-09-01

    Full Text Available Abstract Background Accurate diagnosis of Plasmodium spp. is essential for the rational treatment of malaria. Despite its many disadvantages, microscopic examination of blood smears remains the current "gold standard" for malaria detection and speciation. PCR assays offer an alternative to microscopy which has been shown to have superior sensitivity and specificity. Unfortunately few comparative studies have been done on the various molecular based speciation methods. Methods The sensitivity, specificity and cost effectiveness of three molecular techniques were compared for the detection and speciation of Plasmodium falciparum and Plasmodium vivax from dried blood spots collected from 136 patients in western Thailand. The results from the three molecular speciation techniques (nested PCR, multiplex PCR, and real-time PCR were used to develop a molecular consensus (two or more identical PCR results as an alternative gold standard. Results According to the molecular consensus, 9.6% (13/136 of microscopic diagnoses yielded false negative results. Multiplex PCR failed to detect P. vivax in three mixed isolates, and the nested PCR gave a false positive P. falciparum result in one case. Although the real-time PCR melting curve analysis was the most expensive method, it was 100% sensitive and specific and least time consuming of the three molecular techniques investigated. Conclusion Although microscopy remains the most appropriate method for clinical diagnosis in a field setting, its use as a gold standard may result in apparent false positive results by superior techniques. Future studies should consider using more than one established molecular methods as a new gold standard to assess novel malaria diagnostic kits and PCR assays.

  18. Fabrication of bulk metallic glasses by centrifugal casting method

    OpenAIRE

    R. Nowosielski; R. Babilas

    2007-01-01

    Purpose: The aim of the present work is characterization of the centrifugal casting method, apparatus andproduced amorphous materials, which are also known as bulk metallic glassesDesign/methodology/approach: The studied centrifugal casting system consists of two main parts: castingapparatus and injection system of molten alloy. The described centrifugal casting method was presented bypreparing a casting apparatus “CentriCast – 5”. The apparatus includes a cylindrical copper mold, which isrot...

  19. A multi-method approach for the study of lanthanum speciation in coastal and estuarine sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Babu, P.V.R.; Sarma, V.V.

    measurement Analyzing experimental data to obtain physical parameters is a crucial point in the kinetic speciation method. In this paper, data was fitted to the kinetic model by non-linear regression analysis using the Marquadt-Levenberg algorithm... of components is not a simple issue. The small number of components with specific rate constants may not accurately describe the chemistry of the binding sites of sediment. A binding site may have a range of binding energy because of the heterogeneous nature...

  20. On the reliability of methods for the speciation of mercury based on chromatographic separation coupled to atomic spectrometric detection

    OpenAIRE

    Qvarnström, Johanna

    2003-01-01

    This thesis deals with the reliability of methods for the speciation of mercury in environmental and biological samples. Problems with speciation methods that couple chromatography to atomic spectrometric detection and how to overcome the problems are discussed. Analytical techniques primarily studied and evaluated are high performance liquid chromatography-cold vapour-atomic absorption spectrometry (HPLC-CV-AAS), HPLC-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS), capillary elec...

  1. Dating methods about bulk sediments in marine environment

    International Nuclear Information System (INIS)

    With the development of science and technology progress, the studies about dating methods of sediments become more and more precise. Widely used of so many dating methods have offered reliable scientific evidence for the foundation of accurate chronostratigraphic framework in different region. Considering the difference of sedimentary environment as well as sediment types between inland and submarine, the dating method should be secerned. However, there are few articles which specially introduce the dating methods about bulk sediments in submarine environment. Based on the conclusion and summarized about many dating methods, especially focus on the sediment types and dating range,the conformable isotope dating methods (210Pb, 14C), OSL dating and comparatively dating methods (ie., Oxygen isotope curve, Paleomagnetic) which suitable for the bulk sediments in marine environment are suggested. Dating have an very important function in marine geological studies. In order to enhance the veracity and reliability of the dating data, the proper methods based on sediment types and estimated age range are selected. On the other hand,the progress cross-comparison during different dating methods are given. (authors)

  2. Mercury Speciation by X-ray Absorption Fine Structure Spectroscopy and Sequential Chemical Extractions: A Comparison of Speciation Methods

    Science.gov (United States)

    Kim, C.S.; Bloom, N.S.; Rytuba, J.J.; Brown, Gordon E., Jr.

    2003-01-01

    Determining the chemical speciation of mercury in contaminated mining and industrial environments is essential for predicting its solubility, transport behavior, and potential bioavailability as well as for designing effective remediation strategies. In this study, two techniques for determining Hg speciation-X-ray absorption fine structure (XAFS) spectroscopy and sequential chemical extractions (SCE)-are independently applied to a set of samples with Hg concentrations ranging from 132 to 7539 mg/kg to determine if the two techniques provide comparable Hg speciation results. Generally, the proportions of insoluble HgS (cinnabar, metacinnabar) and HgSe identified by XAFS correlate well with the proportion of Hg removed in the aqua regia extraction demonstrated to remove HgS and HgSe. Statistically significant (> 10%) differences are observed however in samples containing more soluble Hg-containing phases (HgCl2, HgO, Hg3S2O 4). Such differences may be related to matrix, particle size, or crystallinity effects, which could affect the apparent solubility of Hg phases present. In more highly concentrated samples, microscopy techniques can help characterize the Hg-bearing species in complex multiphase natural samples.

  3. A new method for antimony speciation in plant biomass and nutrient media using anion exchange cartridge.

    Science.gov (United States)

    Tisarum, Rujira; Ren, Jing-Hua; Dong, Xiaoling; Chen, Hao; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartridge in DI water, Sb(III) was retained in citric acid media. At pH 6, Sb(III) and Sb(V) formed Sb(III)- and Sb(V)-citrate complexes, but the cartridge had higher affinity towards the Sb(III)-citrate complex. Separation of Sb(III) was tested at various concentrations in fresh and spent growth media and plant tissues. Our results showed that cartridge-based Sb speciation was successful in plant tissues, which was confirmed by HPLC-ICP-MS. The cartridge retained Sb(III) and showed 92-104% Sb(V) recovery from arsenic hyperaccumulator Pteris vittata roots treated with Sb(III) and Sb(V). The cartridge procedure is an effective alternative for Sb speciation, offering low cost, reproducible results, and simple Sb analysis using GFAAS. PMID:26452943

  4. Bulk properties of light actinides: modified second variation method

    International Nuclear Information System (INIS)

    The second variation method is a common and efficient way of treating the spin-orbit coupling within electronic structure codes. While it works satisfactorily for most elements, it was demonstrated recently to be inadequate for light actinides. The problem was traced back to insufficient description of the 6p states, resulting in a poor convergence of the total energies with respect to the computational parameters. We present a simple way to overcome this deficiency and demonstrate its effect on the stability of the calculation. The results obtained for bulk properties of light actinides (Th-Pu) are compared to those obtained with methods using full Dirac formalism. (author)

  5. Positron methods for the study of defects in bulk materials

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard

    The basic principles of positron annihilation physics are briefly discussed and the three most important experimental techniques used for bulk studies are described (i.e. positron lifetime, angular correlation, Doppler broadening). Several examples of the use of the positron methods are discussed...... for metals, ceramics and molecular materials, which illustrate the sensitivity of the positron annihilation techniques to vacancy type defects. For example it is shown how information can be obtained about vacancy formation energies, vacancy migration and clustering, vacancy-impurity interactions......, densities of rare gasses in bubbles in metals, and about free volume in molecular materials....

  6. Zinc mobility and speciation in soil covered by contaminated dredged sediment using micrometer-scale and bulk-averaging X-ray fluorescence, absorption and diffraction techniques

    Science.gov (United States)

    Isaure, Marie-Pierre; Manceau, Alain; Geoffroy, Nicolas; Laboudigue, Agnès; Tamura, Nobumichi; Marcus, Matthew A.

    2005-03-01

    The mobility and solid-state speciation of zinc in a pseudogley soil (pH = 8.2-8.3) before and after contamination by land-disposition of a dredged sediment ([Zn] = 6600 mg kg -1) affected by smelter operations were studied in a 50 m 2 pilot-scale test site and the laboratory using state-of-the-art synchrotron-based techniques. Sediment disposition on land caused the migration of micrometer-sized, smelter-related, sphalerite (ZnS) and franklinite (ZnFe 2O 4) grains and dissolved Zn from the sediment downwards to a soil depth of 20 cm over a period of 18 months. Gravitational movement of fine-grained metal contaminants probably occurred continuously, while peaks of Zn leaching were observed in the summer when the oxidative dissolution of ZnS was favored by non-flooding conditions. The Zn concentration in the contaminated soil. Bulk average powder EXAFS spectroscopy was used to quantify the proportion of each Zn species in the soil. In the uncontaminated soil, Zn is largely speciated as Zn-containing phyllosilicate, and to a minor extent as zincochromite (ZnCr 2O 4), IVZn-sorbed turbostratic birnessite (δ-MnO 2), and Zn-substituted goethite. In the upper 0-10 cm of the contaminated soil, ˜60 ± 10% of total Zn is present as ZnS inherited from the overlying sediment. Poorly-crystalline Zn-sorbed Fe (oxyhydr)oxides and zinciferous phyllosilicate amount to ˜20-30 ± 10% each and, therefore, make up most of the remaining Zn. Smaller amounts of franklinite (ZnFe 2O 4), Zn-birnessite and Zn-goethite were also detected. Further solubilization of the Zn inventory in the sediment, and also remobilization of Zn from the poorly-crystalline neoformed Fe (oxyhydr)oxide precipitates, are expected over time. This study shows that land deposition of contaminated dredged sediments is a source of Zn for the covered soil and, consequently, presents environmental hazards. Remediation technologies should be devised to either sequester Zn into sparingly soluble crystalline phases, or

  7. Uranium speciation as a function of depth in contaminated hanford sediments--a micro-XRF, micro-XRD, and micro- and bulk-XAFS study.

    Science.gov (United States)

    Singer, David M; Zachara, John M; Brown, Gordon E

    2009-02-01

    The distribution and speciation of U and Cu in contaminated vadose zone and aquifer sediments from the U.S. DOE Hanford site (300 Area) were determined using a combination of synchrotron-based micro-X-ray fluorescence (microXRF) imaging, micro-X-ray absorption near edge structure (microXANES) spectroscopy, and micro-X-ray diffraction (microXRD) techniques combined with bulk U LIII-edge X-ray absorption fine structure (XAFS) spectroscopy. Samples were collected from within the inactive North Process Pond (NPP2) at 8 ft (2.4 m, NPP2-8) depth and 12 ft (3.7 m, NPP2-12) depth in the vadose zone, and fines were isolated from turbid groundwater just below the water Table (12-14 ft, approximately 4 m, NPP2-GW). microXRF imaging, microXRD, and microXANES spectroscopy revealed two major U occurrences within the vadose and groundwater zones: (1) low to moderate concentrations of U(VI) associated with fine-textured grain coatings that were consistently found to contain clinochlore (referred to here as chlorite) observed in all three samples, and (2) U(VI)-Cu(II) hotspots consisting of micrometer-sized particles associated with surface coatings on grains of muscovite and chlorite observed in samples NPP2-8' and NPP2-GW. In the aquifer fines (NPP2-GW), these particles were identified as cuprosklodowskite (cps: Cu[(UO2)(SiO2OH)]2 x 6H2O) and metatorbernite (mtb: Cu(UO2)2(PO4)2 x 8H2O). In contrast, the U-Cu-containing particles in the vadose zone were X-ray amorphous. Analyses of U LIII-edge XAFS spectra by linear-combination fitting indicated that U speciation consisted of (1) approximately 75% uranyl sorbed to chlorite and approximately 25% mtb-like X-ray amorphous U-Cu-phosphates (8 ft depth), (2) nearly 100% sorbed uranyl (12 ft depth), and (3) approximately 70% uranyl sorbed to chlorite and approximately 30% cps/mtb (groundwater zone). These findings suggest that dissolution of U(VI)-Cu(II)-bearing solids as well as desorption of U(VI), mainly from phyllosilicates, are

  8. Redox speciation of final repository relevant elements using separation methods in combination with ICP mass spectrometry

    International Nuclear Information System (INIS)

    The long-term safety assessment for nuclear waste repositories requires a detailed understanding of the chemistry of actinide elements in the geosphere. The development of advanced analytical tools is required to gain detailed insights into actinide redox speciation in a given system. The mobility of radionuclides is mostly determined by the geochemical conditions which control the redox state of radionuclides. Besides the longlived radionuclides plutonium (Pu) and neptunium (Np), which are key elements in high level nuclear waste, iron (Fe) represents a main component in natural systems controlling redox related geochemical processes. Analytical techniques for determining oxidation state distribution for redox sensitive radionuclides and other metal ions often have a lack of sensitivity. The detection limits of these methods (i.e. UV/vis, TRLFS, XANES) are in general in the range of ≥ 10-6 mol.L-1. As a consequence ultrasensitive new analytical techniques are required. Capillary electrophoresis (CE) and ion chromatography (IC) are powerful separation methods for metal ions. In the course of this thesis different speciation method for iron, neptunium and plutonium were optimized. With the optimized setup redox speciation analysis of these elements in different samples were done. Furthermore CE hyphenated to inductively coupled plasma sector field mass spectrometry (CE - ICP - SF - MS) was used to measure the redox speciation of Pu (III, IV, V, VI), Np (IV, V, VI) and Fe (II, III) at concentrations lower than 10-7 mol.L-1. CE coupling and separation parameters such as sample gas pressure, make up flow rate, capillary position, auxiliary gas flow, as well as the electrolyte system were optimized to obtain the maximum sensitivity. The methodes detection limits are 10-12 mol.L-1 for Np and Pu. The various oxidation state species of Pu and Np in different samples were separated by application of an acetate based electrolyte system. The separation of Fe (II) and Fe

  9. Methods for analysis of the distribution and speciation of iron and zinc in the cereal grain

    DEFF Research Database (Denmark)

    Hansen, Thomas Hesselhøj

    identification of P and S with mineral micronutrients can therefore be a circumstantial evidence for their chemical speciation. The focus of this PhD has therefore been on the analysis of mineral micronutrients as well as S and P. In this PhD, four methods for elemental analysis of the cereal grain have been...... novel high-throughput micro digestion method was developed, enabling the analysis of total element concentrations in small tissue fractions, such as the embryo of cereal grains. The method is based on small closed bombs that are microwaved and was validated for sample amounts between 1-20 mg using...... certified reference materials. This enabled high-throughput analysis of different grain tissue fractions and the variability in between them.. Moreover two methods for quantitative hyphenated ICP-MS analysis were developed. One enabled quantification of species in a chromatographic separation and the other...

  10. Measurement of critical current for bulk superconductors by transport method

    International Nuclear Information System (INIS)

    The method of critical current measurement in a magnetic field using a DC transport current has been developed for bulk superconductors. The measurement of the critical current, Ic, up to 50A at a temperature of 77K became possible by reducing thermal and mechanical stresses caused in the sample due to rapid cooling from the room temperature to 77K and a electromagnetic force (Lorentz force), etc. The critical current of 50A is reduced into 14,000A/cm2 of critical current density, Jc, with a cross section of 0.0035cm2. The magnetic field dependence of Jc was investigated from 1T to 10T for (Nd0.33Eu0.38Gd0.28)Ba2Cu3Oy bulk superconductors. The magnetization measurement was performed for the sample cut out from the same part of the same crystal as that used for the transport measurement of Ic, from which the critical current density was also estimated. In low magnetic fields, the magnitude of critical current density obtained by the transport method, JcT, was larger than that estimated from the magnetization, JcM. This result reflects the difference of criterion to determine the value of JcT and JcM. In higher magnetic fields, however, it was observed that JcT was smaller than JcM and the irreversibility field estimated from JcT-B curve is slightly lower than that given by the magnetic hysteresis. When the external magnetic field was applied, anomalous voltage peaks in the I-V curve were observed below IcT, which may be caused by the sample slightly moving by the Lorentz force

  11. A method of determining the bulk strength of strata

    International Nuclear Information System (INIS)

    The bulk strength of rocks in strata is determined by logging a borehole with a neutron-neutron or neutron-gamma log to determine the Hydrogen Index log of the borehole and the lithology of the surrounding strata. The log is modified by a predetermined mathematical function for each lithology group of rocks in the strata. The bulk strength of each individual rock in the lithology is calculated from the modified hydrogen log using a polynomial expression. (author)

  12. Speciation and detection of arsenic in aqueous samples: A review of recent progress in non-atomic spectrometric methods

    International Nuclear Information System (INIS)

    Highlights: • Compilation of principal official documents and major review articles, including the toxicology and chemistry of As. • Review of non-atomic spectrometric methods for speciation and detection of arsenic in aqueous samples (2005–2013) of the performance of field-usable methods. - Abstract: Inorganic arsenic (As) displays extreme toxicity and is a class A human carcinogen. It is of interest to both analytical chemists and environmental scientists. Facile and sensitive determination of As and knowledge of the speciation of forms of As in aqueous samples are vitally important. Nearly every nation has relevant official regulations on permissible limits of drinking water As content. The size of the literature on As is therefore formidable. The heart of this review consists of two tables: one is a compilation of principal official documents and major review articles, including the toxicology and chemistry of As. This includes comprehensive official compendia on As speciation, sample treatment, recommended procedures for the determination of As in specific sample matrices with specific analytical instrument(s), procedures for multi-element (including As) speciation and analysis, and prior comprehensive reviews on arsenic analysis. The second table focuses on the recent literature (2005–2013, the coverage for 2013 is incomplete) on As measurement in aqueous matrices. Recent As speciation and analysis methods based on spectrometric and electrochemical methods, inductively coupled plasma-mass spectrometry, neutron activation analysis and biosensors are summarized. We have deliberately excluded atomic optical spectrometric techniques (atomic absorption, atomic fluorescence, inductively coupled plasma-optical emission spectrometry) not because they are not important (in fact the majority of arsenic determinations are possibly carried out by one of these techniques) but because these methods are sufficiently mature and little meaningful innovation has been

  13. A method for a comparison of bulk energy transport systems.

    Science.gov (United States)

    Oudalov, Alexandre; Lave, Lester B; Reza, Muhamad; Bahrman, Michael P

    2009-10-15

    We model alternatives for moving bulk energy, including both private costs and accounting for environmental externalities by requiring the transport system to satisfy environment health, and safety standards. In particular, we focus on the cost and environmental trade-offs between "coal by wire," mine-mouth generation with electricity transmission, and transporting the primary energy resources with generation near the customer. Having the bulk energy transport model satisfy standards avoids the controversy associated with estimating dollar costs for constrained visibility, noise, and 50/60 Hz electromagnetic fields. A sensitivity analysis examines the implications of a range of carbon-dioxide discharge charges. PMID:19921870

  14. Novel separation method for highly sensitive speciation of cancerostatic platinum compounds by HPLC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Hann, S.; Stefanka, Z.; Lenz, K.; Stingeder, G. [University of Natural Resources and Applied Life Sciences, Department of Chemistry, Vienna (Austria)

    2005-01-01

    A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method is presented for analysis of cisplatin, monoaquacisplatin, diaquacisplatin, carboplatin, and oxaliplatin in biological and environmental samples. Chromatographic separation was achieved on pentafluorophenylpropyl-functionalized silica gel. For cisplatin, carboplatin, and oxaliplatin limits of detection of 0.09, 0.10, and 0.15 {mu}g L{sup -1}, respectively, were calculated at m/z194, using aqueous standard solutions. (3 {mu}L injection volume). The method was utilized for model experiments studying the stability of carboplatin and oxaliplatin at different chloride concentrations simulating wastewater and surface water conditions. It was found that a high fraction of carboplatin is stable in ultrapure water and in solutions containing 1.5 mol L{sup -1} Cl{sup -}, whereas oxaliplatin degradation was increased by increasing the chloride concentration. In order to support the assessment of oxaliplatin eco-toxicology, the method was tested for speciation of patient urine. The urine sample contained more than 17 different reaction products, which demonstrates the extensive biotransformation of the compound. In a second step of the study the method was successfully evaluated for monitoring cancerostatic platinum compounds in hospital waste water. (orig.)

  15. Development of methods for the speciation of metals in atmospheric particulate matter

    Science.gov (United States)

    Majestic, Brian J.

    2007-12-01

    This study focuses on advancing methods to measure and speciate trace-elements in atmospheric particulate matter (PM) to support human exposure and health studies. Methods were developed to measure Fe(II) and Fe(III) in PM samples using samplers collecting daily average particulate matter samples and personal exposure samples. Low-cost wet-chemical methods were also developed to measure the oxidation state of leachable iron, chromium and manganese present in low-volume PM samples. In addition, a study was conducted to determine if metals collected by different personal exposure samplers currently used in exposure and health studies were comparable. Results from the intercomparison study between co-located personal and fixed-site ambient samplers showed that different personal sampler designs display biases that are largest for metals predominating in the super-micron fraction. Using one consistent personal exposure sampler, a pilot study was conducted to examine trace-metal concentrations in personal exposure samples from individuals residing in an assisted-living home. These results were compared to ambient outdoor and fixed-indoor concentrations, and generally, outdoor > indoor > personal exposure concentrations. The pilot study demonstrated that adequate tools exist to measure trace-element exposures under real-world conditions. Using the methods developed in the study, labile Fe(II) and Fe(III) as well as total soluble manganese and soluble oxidized manganese from atmospheric PM were routinely detected in ambient and personal exposure samples. Samples extracted in a variety of environmentally and biologically relevant fluids showed that leachable iron and manganese strongly depends on the extractant. Atmospheric samples from a residential location in Toronto (which uses the fuel additive, MMT) showed that a significant fraction of oxidized labile manganese is present in the PM2.5 fraction, in contrast to US cities that do not use MMT. Both the wet-chemical and

  16. A simple automated method for the speciation of dissolved inorganic nitrogen in seawater

    International Nuclear Information System (INIS)

    A new flow injection analysis (FIA) method using spectrophotometric detection has been developed for the simultaneous determination of ammonium, nitrite and nitrate in marine waters. The method is based on absorbance measurement of azo dye obtained by the reaction of nitrite with N-(1-naphthyl)ethylenediamine dihydrochloride and sulfanilamide. Ammonium was previously oxidized to nitrite by hypochlorite in the presence of large amount of potassium bromide, while nitrate was reduced to nitrite in a copperized cadmium column. The conditions of the former reaction have been studied and its continuous application in seawater has been optimized. With a single sample injection three signals were obtained, corresponding to the concentration of nitrite (N-NO2-), nitrite plus ammonium (N-NO2- + N-NH4+) and nitrite plus nitrate (N-NO2- + N-NO3-). The detection limit for each species was 21 μg l-1 N-NO2-, 26 μg l-1 N-NH4+ and 32 μg l-1 N-NO3-. This method was applied to both synthetic and real samples of seawater, giving average relative errors of 3.2, 4.9 and 4.0% for NO2-, N-NH4+, and N-NO3-, respectively. The present method allows for the simultaneous determination and speciation of nitrogenous with a single injection, in a simple way and a high sampling rate (10 samples h-1). Besides, the method enables the monitoring of nitrogen species in marine ecosystems

  17. Determination of sequential extracted uranium speciation in geological samples with HR-ICP-MS method

    International Nuclear Information System (INIS)

    This paper presents a method of determing uranium speciation in geological samples by means of sequential extraction procedure with HR-ICP-MS and its application to sandstone uranium exploration. The extraction chemical procedure is modified from Tessier, uranium in sample is classified into five speclarion: exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to sulfide-organic matter, and residual. The uranium is extracted respectively and the extractants are measured by the high-resolution inductively coupled mass spectrometry (HR-ICP-MS) with high sensitivity and low background. The extraction procedure has been proved to be satisfactory by means of national reference standard materials, international reference standard materials, and artificial uranium mine sample. Experiment results obtained on replicate samples demonstrate that the relative standard deviation (RSD) of the sequential extraction procedure followed by HR-ICP-MS is 2.6 % for bound to carbonates, 4.0% for bound to sulfide -organic matter, 6.0% for residual, 6.1% bound to Fe-Mn oxides, and 26% for exchangeable fraction. The ratio of uranium in bound to uranium carbonates in residual can be used to indicated the probability of buried uranium deposit. (authors)

  18. Development of speciation analytical methods for lanthanides and actinides in lake water

    International Nuclear Information System (INIS)

    Analytical methods for physicochemical speciation of lanthanides and actinides in fresh water samples were developed to explain their behavior in the environment. An inductively coupled plasma mass spectrometer (ICP-MS) was coupled with a size exclusion high performance liquid chromatograph system (SEC). Water samples were collected from various depths by using GO-FLO type water samplers at Lakes Biwa and Towada. Seven water quality parameters such as temperature and pH were measured with a multi water profiler. After filtration by a 0.45 μm pore size membrane filter, target substances in the water samples were pre-concentrated with an ultra-filtration filter, which had cut-off size of 10 kDa. The >10 kDa molecule fraction was concentrated to 1000 times that in the original water sample. The total concentrations of the target materials in the fraction and the original samples were measured separately by ICP-MS. The fraction was introduced to a SEC-ICP-MS, consisting of a GL-540 (Hitachi) for the SEC column, and a HP-4500 (Yokogawa) for the ICP-MS instrument. The buffer solution of 0.01M Tris-HNO3 (pH 7.3) was selected as a mobile phase. Six UV absorption peaks were found in the area under molecular weights of 700 kDa. A single or double peak of each lanthanide or actinide was observed at approximately 160 and 30 kDa, however, the peak positions of the metals did not match the main UV absorption peak. These results demonstrated the applicability of the present method to the environmental fresh water sample, and suggested that most of the lanthanides in the >10 kDa fraction existed as the 160 or 30 kDa organic molecules-metal complexes. (author)

  19. A new measurement method for quantification and speciation of technetium-99 in sample at environmental concentrations

    International Nuclear Information System (INIS)

    Technetium-99 is a pure β- emitter and important long half-lived multi-valent radionuclide to be considered in radiation protection of the environment and the public. It a fission product of both 235U and 239Pu with approximately a 6% yield. The most stable and very mobile form of Tc is the pertechnetate anion (TcO4-). Therefore, environmental monitoring requires the knowledge of the redox and chemical properties of this element in order to predict its behaviour and transfer in the environment. Given the extremely low concentration of 99Tc in the environment (10-10 M to 10-12 M), its determination currently necessitates an enrichment and separation from the sample matrix prior to instrumental measurement. To this end, the development of a suitable analytical technique is required. The advantages of Capillary Electrophoresis (CE) as a powerful separation technique can be combined with the atomic specificity, multi-elemental character and extremely high sensitivity of an inductively coupled plasma mass spectrometer (ICP-MS) for trace metal-speciation studies in different fields of interest. However, the coupling of both commercially available instruments deserves particular attention if separative resolution, high analyte transport efficiency and sensitive detection are to be achieved. In, that technical vein, the interface itself may be considered as the 'key to success'. Several attempts to develop interfaces for CE-ICP-MS have been described over the last few years. However, the 99Tc quantification by ICP-MS can be disturbed by isobaric overlaps 99Ru and interferences induced by the matrix, including those associated with hydride formation (98Mo1H (23.8%), 98Ru1H (1.9%)). The aim of the present study was to develop a rapid and efficient method for the determination of 99Tc in environmental samples by CE-ICP-MS without preliminary classical radiochemical separation to eliminate the interfering elements. In this paper, we describe the development and the analytical

  20. VALIDATED SPECTROPHOTMETRIC METHOD FOR THE DETERMINATION OF SALBUTAMOL SULPHATE IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    Eswarudu.M.M

    2012-04-01

    Full Text Available A new, simple, accurate and sensitive spectrophotometric method has been developed for the estimation of Salbutamol sulphate in bulk and in pharmaceutical formulations. Salbutamol sulphate shows ʎ max at 292 nm. The drug follows the beer’s lambert’s law in the concentration range of 20-100µ ml. the method was validated by following the analytical performance parameters as suggested by the international conference on harmonization which included accuracy, precision, linearity. All validation parameters were with in the acceptable range. The developed method was successfully applied to estimate the amount of Salbutamol sulphate in bulk and pharmaceutical dosage forms.

  1. Speciation analysis of seleno-amino acids in human serum: comparison of methods with and without protein hydrolysis

    International Nuclear Information System (INIS)

    Full text: This study presents the development of a reference method based on (reverse phase) HPLC-ICPMS for the determination of selenomethionine (SeMet) in human serum, following the enzymatic hydrolysis of selenoalbumin (SeAlb), a seleno-containing protein. Quantification of SeMet was carried out by species-specific isotope dilution (SSID); the assessment of the uncertainty budget and the steps contributing significantly to the overall uncertainty are addressed. The SSID HPLC-ICPMS procedure for the determination of SeMet in human serum was compared with a method relying on speciation analysis of intact selenoproteins (i.e. without hydrolysis), namely glutathione peroxidase, selenoprotein P and SeAlb, by means of a affinity-HPLC coupled to ICPMS. (author)

  2. Method optimization and quality assurance in speciation analysis using high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt

    1998-01-01

    operating characteristics of the entire hyphenated system. An isocratic HPLC system, which employs an aqueous mobile phase with organic buffer constituents, is well suited for introduction into the ICP-MS because of the stability of the detector response and high degree of analyte sensitivity attained...... speciation in the shrimp sample. With this analytical technique the HPLC retention time in combination with mass analysis of the molecular ions and their collision-induced fragments provide almost conclusive evidence of the identity of the analyte species. The speciation methods are validated by establishing...

  3. Speciation of arsenic by IC-ICP-MS: future standard method and its application on baby food samples

    DEFF Research Database (Denmark)

    Kollander, Barbro; Sloth, Jens Jørgen

    of the intended murder. For example the organic compound arsenobetaine, the main arsenic species in marine organisms, is regarded as basically harmless to humans while the inorganic forms of arsenic, arsenite and arsenate found in rice, are toxic. To enable the evaluation of the true toxicity from arsenic in food......, some kind of speciation analysis has to be performed. In this work, the concentration of inorganic arsenic in some baby food samples is evaluated. The applied methodology has recently been tested in a collaborative trial as a candidate standardized method for the determination of inorganic arsenic......Arsenic is known to most people as extremely poisonous and several criminal authors have used this fact to assassinate their characters in novels for decades. However, the authors seldom or never mention which of the species of arsenic they use, although that is elementary for the outcome...

  4. Speciation Analysis of Radionuclides in the Environment - NSK-B SPECIATION project report 2009

    OpenAIRE

    Hou, Xiaolin; Aldahan, Ala; Possnert, Göran; Lujaniene, Galina; Lehto, Jukka; Skipperud, Lindis; Lind, Ole Christian; Salbu, Brit

    2009-01-01

    The second stage of the NKS-B project SPECIATION was complemented in 2008-2009, which mainly focus on three aspects: (1) Further improvement and development of methods for speciation analysis of radionuclides; (2) Investigation of speciation of some radionuclides in the environment (water, sediments, particles); and (3) Intercomparison excise for speciation analysis of radionu-clides in soil and sediment. This report summarizes the work completed in the project partners’ laboratories, Method ...

  5. Numerical analysis of bulk drag coefficient in dense vegetation by immersed boundary method

    NARCIS (Netherlands)

    Suzuki, T.; Arikawa, T.

    2010-01-01

    In this paper, bulk drag coefficient in rigid dense vegetation is investigated mainly by using a three dimensional numerical simulation model CADMAS-SURF/3D by incorporating Immersed Boundary Method to calculate flow around the vertical cylinder in the Cartesian grid. Large Eddy Simulation is also i

  6. Simple and economical method for speciation and resistotyping of clinically significant coagulase negative staphylococci.

    Science.gov (United States)

    Goyal, R; Singh, N P; Kumar, A; Kaur, I; Singh, M; Sunita, N; Mathur, M

    2006-07-01

    An attempt was made to speciate 102 clinically significant isolates of coagulase negative staphylococci (CoNS) by a practical scheme adapted from various references. This scheme utilizes slide and tube coagulase test, urease test ornithine decarboxylase, novobiocin susceptibility and aerobic acid from mannose for assigning species group. Inclusion of one or two additional tests in a species group could identify the isolates to species level. Ninety eight (97%) isolates were conveniently identified as S. epidermidis (41%), S. saprophyticus (16.6%), S. haemolyticus (14.7%), S. hominis (14.7%), S. lugdunensis (4.9%), S. schleiferi (1.9%) and S. capitis (1.9%). Only four isolates were not identified to the species level, two of which were probably S. capitis subspecies ureolyticus / S. warneri / S. simulans . Antibiotic susceptibility testing showed maximum resistance to ampicillin (89%) followed by cefotaxime (59%) with no resistance to vancomycin. The increasing recognition of pathogenic potential of CoNS and emergence of drug resistance amongst them denotes the need to adopt simple laboratory procedures to identify and understand the diversity of staphylococci isolated from clinical material. PMID:16912440

  7. Simple and economical method for speciation and resistotyping of clinically significant coagulase negative staphylococci

    Directory of Open Access Journals (Sweden)

    Goyal R

    2006-01-01

    Full Text Available An attempt was made to speciate 102 clinically significant isolates of coagulase negative staphylococci (CoNS by a practical scheme adapted from various references. This scheme utilizes slide and tube coagulase test, urease test ornithine decarboxylase, novobiocin susceptibility and aerobic acid from mannose for assigning species group. Inclusion of one or two additional tests in a species group could identify the isolates to species level. Ninety eight (97% isolates were conveniently identified as S. epidermidis (41%, S. saprophyticus (16.6%, S. haemolyticus (14.7%, S. hominis (14.7%, S. lugdunensis (4.9%, S. schleiferi (1.9% and S. capitis (1.9%. Only four isolates were not identified to the species level, two of which were probably S. capitis subspecies ureolyticus / S. warneri / S. simulans . Antibiotic susceptibility testing showed maximum resistance to ampicillin (89% followed by cefotaxime (59% with no resistance to vancomycin. The increasing recognition of pathogenic potential of CoNS and emergence of drug resistance amongst them denotes the need to adopt simple laboratory procedures to identify and understand the diversity of staphylococci isolated from clinical material.

  8. Fe-based bulk metallic glasses prepared by centrifugal casting method

    Directory of Open Access Journals (Sweden)

    R. Babilas

    2011-10-01

    Full Text Available Purpose: The work presents a casting method, structure characterization and analysis of chosen properties of Fe-based bulk metallic glasses in as-cast state.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4, Fe36Co36B19Si5Nb4, Fe43Co14Ni14B20Si5Nb4 metallic glasses in form of rings. The amorphous structure of tested samples was examined by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM methods. The crystallization behaviour of the studied alloys was examined by differential thermal analysis (DTA. The soft magnetic property examinations of tested materials contained initial magnetic permeability and measurements of magnetic permeability relaxation.Findings: The XRD and TEM investigations revealed that the studied as-cast bulk glassy samples in forms of ring were amorphous for all tested alloys. The SEM images showed that fractures of studied rings indicated two structurally different zones, which contained “river” patterns and “smooth” areas. The samples of studied alloys presented two stage crystallization process, which was observed for all tested rings with different thickness. The changes of crystallization temperatures versus the thickness of the glassy samples were stated. The magnetic permeability relaxation, which is directly proportional to the microvoids concentration in amorphous structure decreased with increase of sample thickness. These results could be assumed as the change of amorphous structure in function of thickness.Practical implications: The centrifugal casting method is very simple, useful and effective method to produce bulk amorphous materials in the form of rings or tubes.Originality/value: The preparation of bulk metallic glasses in the form of rings for three different Fe-based alloy systems is very important for the future progress in research and practical applications of iron-based bulk amorphous materials.

  9. Analysis of Bulk Sample of Salicylic Acid by Application of Hydrotropic Solubilization Method

    OpenAIRE

    Maheshwari R; Chavada V; Varghese S; Shahoo K

    2008-01-01

    In the present investigation, the poorly water-soluble drug, salicylic acid has been solubilized using 0.5 M ibuprofen sodium and 2.0 M sodium salicylate solution as hydrotropic agents for the titrimetric analysis precluding the use of organic solvents. Both hydrotropes are economic and pollution-free. The mean percent estimation of salicylic acid estimated in bulk sample by Indian Pharmacopoeial method is 98.78%. The mean percent estimation by ibuprofen sodium method and sodium salicy...

  10. A Stability Indicating UPLC Method for Candesartan in Bulk Drug Samples

    OpenAIRE

    Gunda Srinivas; Kakumani Kishore Kumar; Gangaram V. Kanumula; M. Vishnu Priya; K. Mukkanti

    2012-01-01

    A simple, sensitive gradient rapid resolution liquid chromatographic assay method has been developed for the quantitative determination of Candesartan Cilexetil in bulk active pharmaceutical ingredient, used for the treatment of hypertension. The developed method is also applicable for the process related impurities determination. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in a gradient mode and quantification was...

  11. Use of neutron reflection method for chemical analysis of bulk samples

    International Nuclear Information System (INIS)

    The aim of our study carried out during the last 5-6 years was to find the hidden organic materials (for example explosives or drugs) in bulk objects with the neutron reflection and activation methods. The applicability of the concept of the differential σβ and integral Σβ reflection cross sections is also demonstrated. Further investigations are also recommended to improve the neutron reflection method. (author)

  12. Correction methods of γ-ray self-absorption in bulk sample

    International Nuclear Information System (INIS)

    Five methods of γ-ray self-absorption correction for bulk sample were investigated. It was clarified that there is no significant difference in quality among four methods, except for one method, while a few percents of discrepancy were observed in case of larger value of attenuation coefficient than 0.1 cm-1. One of those methods is recommended for practical γ-ray spectrometry on account of the simple calculation method and no experimental data needed. Self-absorption for low energy γ-rays with high attenuation coefficient was a little dependent on Ge crystal diameter. (author)

  13. Determination of prilocaine HCl in bulk drug and pharmaceutical formulation by GC-NPD method

    Directory of Open Access Journals (Sweden)

    Atila Alptug

    2013-01-01

    Full Text Available The novel analytical method was developed and validated for determination of prilocaine HCl in bulk drug and pharmaceutical formulation by gas chromatography-nitrogen phosphorus detection (GC-NPD. The chromatographic separation was performed using a HP-5MS column. The calibration curve was linear over the concentration range of 40-1000 ng ml-1 with a correlation coefficient of 0.9998. The limits of detection (LOD and quantification (LOQ of method were 10 ng ml-1 and 35 ng ml-1, respectively. The within-day and between-day precision, expressed as the percent relative standard deviation (RSD% was less than 5.0%, and accuracy (percent relative error was better than 4.0%. The developed method can be directly and easily applied for determination of prilocaine HCl in bulk drug and pharmaceutical formulation using internal standard methodology.

  14. A stability-indicating HPLC method for medroxyprogesterone acetate in bulk drug and injection formulation.

    Science.gov (United States)

    Burana-Osot, Jankana; Ungboriboonpisal, Sooksri; Sriphong, Lawan

    2006-03-18

    A stability-indicating HPLC assay method has been developed and validated for medroxyprogesterone acetate (MPA) in bulk drug and injectable suspension. An isocratic RP-HPLC was achieved on a Hichrom C(18) column (150 mm x 4.6mm i.d., 5 microm) utilizing a mobile phase of methanol 0.020 M acetate buffer pH 5 (65:35, v/v) and a photodiode array detector at 245 nm. The stress testing of MPA was carried out under acidic and alkaline hydrolysis, and oxidation conditions. MPA was well resolved from its degradation products, a main related substance (megestrol acetate) and two preservatives (methyl paraben and propyl paraben) with the resolution >or=2. The proposed method was validated for selectivity, linearity, accuracy, precision and solution stability. The method was found to be suitable for the quality control of MPA in bulk drug and injections as well as the stability-indicating studies. PMID:16242876

  15. Plant Speciation

    OpenAIRE

    Rieseberg, Loren H.; Willis, John H.

    2007-01-01

    Like the formation of animal species, plant speciation is characterized by the evolution of barriers to genetic exchange between previously interbreeding populations. Prezygotic barriers, which impede mating or fertilization between species, typically contribute more to total reproductive isolation in plants than do postzygotic barriers, in which hybrid offspring are selected against. Adaptive divergence in response to ecological factors such as pollinators and habitat commonly drives the evo...

  16. Development and application of an ultratrace method for speciation of organotin compounds in cryogenically archived and homogenized biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Point, David; Davis, W.C.; Christopher, Steven J.; Ellisor, Michael B.; Pugh, Rebecca S.; Becker, Paul R. [Hollings Marine Laboratory, National Institute of Standards and Technology, Analytical Chemistry Division, Charleston, SC (United States); Donard, Olivier F.X. [Laboratoire de Chimie Analytique BioInorganique et Environnement UMR 5034 du CNRS, Pau (France); Porter, Barbara J.; Wise, Stephen A. [National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD (United States)

    2007-04-15

    An accurate, ultra-sensitive and robust method for speciation of mono, di, and tributyltin (MBT, DBT, and TBT) by speciated isotope-dilution gas chromatography-inductively coupled plasma-mass spectrometry (SID-GC-ICPMS) has been developed for quantification of butyltin concentrations in cryogenic biological materials maintained in an uninterrupted cryo-chain from storage conditions through homogenization and bottling. The method significantly reduces the detection limits, to the low pg g{sup -1} level (as Sn), and was validated by using the European reference material (ERM) CE477, mussel tissue, produced by the Institute for Reference Materials and Measurements. It was applied to three different cryogenic biological materials - a fresh-frozen mussel tissue (SRM 1974b) together with complex materials, a protein-rich material (whale liver control material, QC03LH03), and a lipid-rich material (whale blubber, SRM 1945) containing up to 72% lipids. The commutability between frozen and freeze-dried materials with regard to spike equilibration/interaction, extraction efficiency, and the absence of detectable transformations was carefully investigated by applying complementary methods and by varying extraction conditions and spiking strategies. The inter-method results enabled assignment of reference concentrations of butyltins in cryogenic SRMs and control materials for the first time. The reference concentrations of MBT, DBT, and TBT in SRM 1974b were 0.92 {+-} 0.06, 2.7 {+-} 0.4, and 6.58 {+-} 0.19 ng g{sup -1} as Sn (wet-mass), respectively; in SRM 1945 they were 0.38 {+-} 0.06, 1.19 {+-} 0.26, and 3.55 {+-} 0.44 ng g{sup -1}, respectively, as Sn (wet-mass). In QC03LH03, DBT and TBT concentrations were 30.0 {+-} 2.7 and 2.26 {+-} 0.38 ng g{sup -1} as Sn (wet-mass). The concentration range of butyltins in these materials is one to three orders of magnitude lower than in ERM CE477. This study demonstrated that cryogenically processed and stored biological materials are

  17. New Analytical Methods and Their Validation for the Estimation of Etodolac in Bulk and Marketed Formulations

    Directory of Open Access Journals (Sweden)

    Mona Bhalani

    2015-02-01

    Full Text Available Etodolac is non-steroidal anti-inflammatory drug. It is used for the management of mild to moderate pain, fever and inflammation. Purpose: Analytical methods are required to characterize drug substances and drug products composition during all phases of pharmaceutical development. Development of methods to achieve the final goal of ensuring the quality of drug substances and drug products must be implemented. This determination requires highly sophisticated instruments and methods like HPLC, HPTLC and Spectrophotometer. Hence there was a need for the development of newer, simple, sensitive, rapid, accurate and reproducible analytical methods for the routine estimation of etodolac in bulk and pharmaceutical dosage form. Methods: Two simple, sensitive, specific and validated methods (method A and method B have been developed for the quantitative estimation of etodolac in bulk and pharmaceutical dosage form. Method A is based on reaction of etodolac with p-dimethylaminocinnamaldehyde to produce orange colour chromogen which showed λmax at 526.8 nm. In method B, etodolac oxidizes in presence of ferric chloride and hydrogen peroxide which absorbs at λmax at 537.2 nm. Reults: The linearity was found in concentration range of 5-30μg/ml and 2-12μg/ml for method A and method B respectively. The correlation coefficient was found to be 0.9990 and 0.9966 for method A and method B respectively. The methods were validated as per ICH guidelines. The LOD and LOQ for estimation of etodolac were found as 0.0824, 0.0230 for method A and 0.2498, 0.0699 for method B respectively. Conclusions: Proposed methods were successfully applied for the quantitative estimation of etodolac in marketed formulations.

  18. Validated LC Method for the Estimation of Voriconazole in Bulk and Formulation

    OpenAIRE

    Patel C; Dave J; Patel J; Panigrahi B

    2009-01-01

    Reversed phase high performance liquid chromatographic method was developed and validated for the estimation of voriconazole in bulk and formulation using prominence diode array detector. Selected mobile phase was a combination of water:acetonitrile (35:65 % v/v) and wavelength selected was 256 nm. Retention time of voriconazole was 3.95 min. Linearity of the method was found to be 0.1 to 2 µg/ml, with the regression coefficient of 0.999. This method was validated according to ICH...

  19. Analysis of bulk sample of salicylic acid by application of hydrotropic solubilization method

    Directory of Open Access Journals (Sweden)

    Maheshwari R

    2008-01-01

    Full Text Available In the present investigation, the poorly water-soluble drug, salicylic acid has been solubilized using 0.5 M ibuprofen sodium and 2.0 M sodium salicylate solution as hydrotropic agents for the titrimetric analysis precluding the use of organic solvents. Both hydrotropes are economic and pollution-free. The mean percent estimation of salicylic acid estimated in bulk sample by Indian Pharmacopoeial method is 98.78%. The mean percent estimation by ibuprofen sodium method and sodium salicylate method are 99.25% and 98.82%, respectively. The results of analysis by the proposed method are very close to the results of analysis by the standard method. This confirms the accuracy of the proposed method. The proposed method was validated statistically by low values of statistical parameters viz. standard deviation, percent coefficient of variation and standard error. The proposed method is new, accurate, simple and economic.

  20. NEW ANALYTICAL METHODS AND THEIR VALIDATION FOR THE ESTIMATION OF CARVEDILOL IN BULK AND MARKETED FORMULATION

    Directory of Open Access Journals (Sweden)

    Viral Bechara

    2015-02-01

    Full Text Available Carvedilol is cardiovascular agent. Mainly used for the treatment of hypertension, heart failure, and cardiovascular diseases. Purpose: Analytical methods are required to characterize drug substances and drug products composition during all phases of pharmaceutical development. Development of methods to achieve the final goal of ensuring the quality of drug substances and drug products must be implemented in conjunction with an understanding of the chemical behavior and physicochemical properties of the drug substance. This determination requires highly sophisticated instruments and methods like HPLC, HPTLC and Spectrophotometer. Hence there was a need for the development of newer, simple, sensitive, rapid, accurate and reproducible analytical methods for the routine estimation of metoprolol succinate in bulk and pharmaceutical dosage form. Methods: The present work describes two new spectrophotometric methods for the determination of carvedilol in bulk and marketed formulations. Method A is based on oxidation of Carvedilol with ferric ammonium sulphate followed by complex formation of resulting ferrous ion (Fe2+ with potassium ferricyanide to form bluish green coloured chromogen which showed λmax at 582 nm. In Method B is based on the oxidation of 2, 4- Dinitrophenylhydrazine and coupling of the oxidized product with drugs to give brown coloured chromogen which showed λmax at 500.8 nm. Results: The linearity was found in concentration range of 5-30 μg/ml for both Method A and Method B. The correlation coefficient was found 0.997 and 0.9997 for both Method A and Method B respectively. The methods were validated as per ICH guidelines. The LOD and LOQ for estimation of Carvedilol were found as 0.0840, 0.2545 for method A and 0.0667, 0.2021 for method B respectively. Conclusion: Proposed methods were successfully applied for the quantitative estimation of Carvedilol in marketed formulations.

  1. Development of an analytical method for antimony speciation in vegetables by HPLC-hydride generation-atomic fluorescence spectrometry.

    Science.gov (United States)

    Olivares, David; Bravo, Manuel; Feldmann, Jorg; Raab, Andrea; Neaman, Alexander; Quiroz, Waldo

    2012-01-01

    A new method for antimony speciation in terrestrial edible vegetables (spinach, onions, and carrots) was developed using HPLC with hydride generation-atomic fluorescence spectrometry. Mechanical agitation and ultrasound were tested as extraction techniques. Different extraction reagents were evaluated and optimal conditions were determined using experimental design methodology, where EDTA (10 mmol/L, pH 2.5) was selected because this chelate solution produced the highest extraction yield and exhibited the best compatibility with the mobile phase. The results demonstrated that EDTA prevents oxidation of Sb(III) to Sb(V) and maintains the stability of antimony species during the entire analytical process. The LOD and precision (RSD values obtained) for Sb(V), Sb(III), and trimethyl Sb(V) were 0.08, 0.07, and 0.9 microg/L and 5.0, 5.2, and 4.7%, respectively, for a 100 microL sample volume. The application of this method to real samples allowed extraction of 50% of total antimony content from spinach, while antimony extracted from carrots and onion samples ranged between 50 and 60 and 54 and 70%, respectively. Only Sb(V) was detected in three roots (onion and spinach) that represented 60-70% of the total antimony in the extracts. PMID:22970588

  2. Bulk synthesis of nanocrystalline urania powders by citrate gel-combustion method

    Science.gov (United States)

    Sanjay Kumar, D.; Ananthasivan, K.; Venkata Krishnan, R.; Amirthapandian, S.; Dasgupta, Arup

    2016-01-01

    Bulk quantities (60 g) of nanocrystalline (nc) free flowing urania powders with crystallite size ranging from 38 to 252 nm have been synthesized for the first time by the citrate gel combustion method. A systematic study of the influence of the fuel (citric acid) to oxidant (nitrate) ratio (R) on the characteristics of the urania powders has been carried out for the first time. Mixture with an "R" value of 0.25 exhibited a vigorous auto-ignition reaction. This reaction was investigated with Differential Scanning Calorimetry (DSC) and in-situ thermogravimetry coupled with differential thermal analysis and mass spectrometry (TG-DTA-MS). The bulk density, specific surface area, X-ray crystallite size, residual carbon and size distribution of particles of this powder were unique. Microscopic and microstructural investigation of selected samples revealed the presence of nanocrystals with irregular exfoliated morphology; their Electron Energy Loss Spectra testified the covalency of the U-O bond.

  3. Magnetic fields end-face effect investigation of HTS bulk over PMG with 3D-modeling numerical method

    Science.gov (United States)

    Qin, Yujie; Lu, Yiyun

    2015-09-01

    In this paper, the magnetic fields end-face effect of high temperature superconducting (HTS) bulk over a permanent magnetic guideway (PMG) is researched with 3D-modeling numerical method. The electromagnetic behavior of the bulk is simulated using finite element method (FEM). The framework is formulated by the magnetic field vector method (H-method). A superconducting levitation system composed of one rectangular HTS bulk and one infinite long PMG is successfully investigated using the proposed method. The simulation results show that for finite geometrical HTS bulk, even the applied magnetic field is only distributed in x-y plane, the magnetic field component Hz which is along the z-axis can be observed interior the HTS bulk.

  4. HPTLC method for quantitative determination of granisetron hydrochloride in bulk drug and in tablets

    OpenAIRE

    Lakshmana Prabu, S.; Selvamani, P.; S Latha

    2010-01-01

    A new simple, rapid and reproducible high performance thin layer chromatographic method has been developed and validated for the analysis of granisetron hydrochloride (GSH) in bulk drug and from pharmaceutical formulation. The chromatographic separation was achieved on HPTLC aluminium plates precoated with silica gel 60F254 as the stationary phase with chloroform: methanol (80:20 %v/v) as mobile phase. The method gives a compact band for GSH (Rf value of 0.45 ± 0.02). Densitometric analysis o...

  5. HPLC METHOD DEVELOPMENT OF AMLODIPINE BY RP-HPLC IN ITS BULK DOSAGE FORMS

    OpenAIRE

    V. Naveen Kumar, K. Kiran kumar, P. Ramesh Babu, K. Anilkumar

    2012-01-01

    A new, simple, precise, sensitive, accurate and reproducible Reverse phase HPLC method was developed and validated for the analysis of amlodipine in bulk dosage forms. The separation was conducted by using c-18 RP-HPLC coloumn, which was maintained at ambient temperature. The mobile phase consisting of Phosphate buffer and Acetonitrile (90:10v/v) was delivered at a rate of 1.5 ml/min. The analysis was detected by using UV detector at the wave length of 225nm.The method is validated for its ...

  6. Fe-based bulk metallic glasses prepared by centrifugal casting method

    OpenAIRE

    R. Babilas; R. Nowosielski

    2011-01-01

    Purpose: The work presents a casting method, structure characterization and analysis of chosen properties of Fe-based bulk metallic glasses in as-cast state.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4, Fe36Co36B19Si5Nb4, Fe43Co14Ni14B20Si5Nb4 metallic glasses in form of rings. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The crystallization...

  7. UV Spectrophotometric Method for Estimation of Polypeptide-K in Bulk and Tablet Dosage Forms

    Science.gov (United States)

    Kaur, P.; Singh, S. Kumar; Gulati, M.; Vaidya, Y.

    2016-01-01

    An analytical method for estimation of polypeptide-k using UV spectrophotometry has been developed and validated for bulk as well as tablet dosage form. The developed method was validated for linearity, precision, accuracy, specificity, robustness, detection, and quantitation limits. The method has shown good linearity over the range from 100.0 to 300.0 μg/ml with a correlation coefficient of 0.9943. The percentage recovery of 99.88% showed that the method was highly accurate. The precision demonstrated relative standard deviation of less than 2.0%. The LOD and LOQ of the method were found to be 4.4 and 13.33, respectively. The study established that the proposed method is reliable, specific, reproducible, and cost-effective for the determination of polypeptide-k.

  8. Method Development and Validation of Montelukast in Bulk and Pharmaceutical Dosage form by RP-HPLC

    Directory of Open Access Journals (Sweden)

    Minaketan Sahoo

    2012-09-01

    Full Text Available The present work describes a simple, precise and accurate HPLC method for estimation of montelukast sodium in bulk and in tablet dosage form. Montelukast sodium is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene (CysLT1 receptor. The separation was achieved by using Waters symmetry shield RP-C8 column and acetonitrile: sodium di-hydrogen Phosphate dehydrate (pH 3.7 in proportion of 70:30 v/v as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 225 nm. The retention time of montelukast sodium was found to be 3.721 min. The limit of detection was found 0.1357 µg/ml and limit of quantification 0.4111 µg/ml. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity (1-30 µg/ml, accuracy, precision, robustness and specificity according to ICH guidelines. The method was statistically validated and RSD was found to be less than 2% indicating high degree of accuracy and precision of the proposed HPLC method. Due to its simplicity, rapidness, high precision and accuracy, the proposed HPLC method may be used for determining Montelukast in bulk or in pharmaceutical dosage forms.

  9. Method optimization for the determination of total arsenic and selenium content in fish by ICP-MS preceding to speciation studies.

    OpenAIRE

    Inês, Coelho; Ribeiro, Sandra; Castanheira, Isabel

    2011-01-01

    The present work constitutes the first task of a three year project that aims for the optimization and validation of a methodology to determine the total concentration of Arsenic (As) and Selenium (Se) and its species in fish products by using HPLC-ICP-MS. Prior to initializing speciation studies the method for determination of total arsenic and selenium content was optimized. For that purpose reference materials (DORM-3 and BCR-627) were used as well as spiked samples. Sample preparation ...

  10. METHOD DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD IN THE DETECTION OF EFAVIRENZ IN BULK DRUG AND TABLET FORMULATION

    Directory of Open Access Journals (Sweden)

    Brajendra singh Rajpoot

    2012-07-01

    Full Text Available A simple, highly sensitive, isocratic reversed phase high performance liquid chromatography (RP-HPLC was developed for the determination of efavirenz in the bulk drug and tablet dosage forms. Elution medium consisting of a mixture of methanol and water in the ratio of (89:11, v/v at flow rate 1ml/min was employed in this study. The retention time of efavirenz was found 2.58 min. The calibration curves were linear with regression coefficient (r2 of 0.9999. The proposed method was extensively validated for linearity, range, accuracy, precision and specificity. The proposed method is sensitive, specific and was successfully applied for the estimation of efavirenz in pharmaceutical formulations (bulk drug and tablet.

  11. Stability-Indicating HPTLC Method for Determination of Duloxetine Hydrochloride in Bulk Drug and Tablet Formulation

    Directory of Open Access Journals (Sweden)

    Sheikh Shahnawaz

    2011-01-01

    Full Text Available A simple, accurate, precise, sensitive, selective, and stability-indicating high-performance thin-layer chromatographic method was developed and validated for determination of duloxetine hydrochloride both in bulk drug as well as in tablet formulation. The stationary phase used in our method consisted of HPTLC aluminum plates precoated with silica gel 60F-254, while, chloroform : methanol (8 : 2, v/v was used as binary mobile phase. These chromatographic conditions eluted the drug effectively, and distinct compact spots were seen, (Rf, retardation factor, value (0.42 ± 0.20. Densitometric determination of duloxetine hydrochloride was carried out in the absorbance mode at a wavelength of 217 nm. The mean value of corelation coefficient; slope and intercept were 0.9962 ± 0.0015, 121.54 ± 0.61, and 987.3 ± 6.17, in the amount range of 600–2000 ng (nanogram per spot, respectively. Stress testing validation were performed as per the guidelines of International Conference on Harmonization (ICH and drug was subjected to stress conditions like acid-hydrolysis, alkali-hydrolysis, oxidation, and thermal degradation. As the method effectively separated the active drug from its degradation products, it can be employed as a stability-indicating assay method (SIAM for identification and quantitative determination of duloxetine HCl in bulk drug and tablet dosage formulation.

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

    Science.gov (United States)

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

    2015-09-01

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

  13. HPLC METHOD DEVELOPMENT OF AMLODIPINE BY RP-HPLC IN ITS BULK DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    V. Naveen Kumar, K. Kiran kumar, P. Ramesh Babu, K. Anilkumar

    2012-06-01

    Full Text Available A new, simple, precise, sensitive, accurate and reproducible Reverse phase HPLC method was developed and validated for the analysis of amlodipine in bulk dosage forms. The separation was conducted by using c-18 RP-HPLC coloumn, which was maintained at ambient temperature. The mobile phase consisting of Phosphate buffer and Acetonitrile (90:10v/v was delivered at a rate of 1.5 ml/min. The analysis was detected by using UV detector at the wave length of 225nm.The method is validated for its specificity, precision, accuracy, linearity and robustness. The method was found to be linear over the concentration range 10-100 g/ml (r2 =0.999. The retention time for amlodipine was found to be 3.34min. Limit of quantification of the method is 0.179g/ml and limit of detection is 0.054 g/ml.

  14. Method Development and Validation of Montelukast in Bulk and Pharmaceutical Dosage form by RP-HPLC

    OpenAIRE

    Minaketan Sahoo

    2012-01-01

    The present work describes a simple, precise and accurate HPLC method for estimation of montelukast sodium in bulk and in tablet dosage form. Montelukast sodium is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene (CysLT1) receptor. The separation was achieved by using Waters symmetry shield RP-C8 column and acetonitrile: sodium di-hydrogen Phosphate dehydrate (pH 3.7) in proportion of 70:30 v/v as mobile phase, at a flow rate of 1.5 ml/min....

  15. Surface and bulk scattering by magnetic and dielectric inhomogeneities: a first-order method

    International Nuclear Information System (INIS)

    The scattering of a magneto-dielectric multilayer has been studied by a first-order method. The model reported in this manuscript relies on the equivalence between heterogeneities of the medium and fictitious electric and magnetic sources. Types of inhomogeneities considered are roughness and bulk inhomogeneities and concern both permittivity and permeability. The numerical results are compared to those given in previous papers for optical scattering. It is shown in the microwave spectra that angle-resolved scattering allows identification of the scattering origins (permittivity or permeability spectra). The cases of isotropic films and meta-materials are presented and discussed. (authors)

  16. Surface and bulk scattering by magnetic and dielectric inhomogeneities: a first-order method.

    Science.gov (United States)

    Dieudonné, É; Malléjac, N; Amra, C; Enoch, S

    2013-09-01

    The scattering of a magnetodielectric multilayer has been studied by a first-order method. The model reported in this manuscript relies on the equivalence between heterogeneities of the medium and fictitious electric and magnetic sources. Types of inhomogeneities considered are roughness and bulk inhomogeneities and concern both permittivity and permeability. The numerical results are compared to those given in previous papers for optical scattering. It is shown in the microwave spectra that angle-resolved scattering allows identification of the scattering origins (permittivity or permeability spectra). The cases of isotropic films and metamaterials are presented and discussed. PMID:24323258

  17. Methods for the speciation and determination of arsenic and selenium in coal combustion products

    Energy Technology Data Exchange (ETDEWEB)

    Schabron, J.F.; Hart, B.K.; Niss, N.D.; Brown, T.H.

    1991-11-01

    Methods of sample preparation for the determination of total selenium, and selenite, selenate, arsenite, and arsenate in coal fly ash materials were evaluated. The measurement methods use atomic spectroscopy for the determination of total concentrations and ion chromatography (IC) for the determination of individual ionic species. Sample preparation procedures which minimize the loss or alteration of the species of interest was explored and defined. The utility of the sample preparation methods can be sample dependent, so caution is advised in their use. IC conditions were established for the determination in extract solutions of selenite, selenate, arsenite, and arsenate with minimal interference from common anions.

  18. Alternative method to determine the bulk etch rate of Lr-115 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, D.; Sajo B, L.; Barros, H.; Greaves, E. D. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. Postal 89000, Caracas (Venezuela, Bolivarian Republic of); Palacios, F. [Universidad de Oriente, Santiago de Cuba (Cuba)

    2010-02-15

    The measurements using the Lr-115 solid-state nuclear track detector depend critically on the removed thickness of the active layer during etching. In this work, Lr-115 detectors exposed to alpha particles were etched under no stirring in a 2.5 N NaOH solution at a temperature of 60{+-}1 C and different etching times (from 0.5 to 2.5 hours). The thickness of the removed layer was determined by a variant of the gravimetric method, so that the bulk etch rate could be deduced from mass change measurements of detectors. The bulk etch rate was found to be 3.63 {+-} 0.09 {mu}m.h{sup -}1, which agrees with most of the reported values. Comparisons of our results with the obtained by the optical density method are in correspondence. We propose here a fast, simple, and nondestructive method to determine the active-layer thickness of the Lr-115 solid-state nuclear track detector with good accuracy for routine measurements. (Author)

  19. Defence Research and Development Canada: Suffield research on nuclear methods for detection of buried bulk explosives

    Science.gov (United States)

    McFee, John E.; Faust, Anthony A.

    2011-06-01

    Defence R&D Canada - Suffield has conducted research and development on nuclear methods for detection of bulk explosives since 1994. Initial efforts were directed at confirmation of the presence of bulk explosives in land mines and improvised explosive devices (IEDs). In close collaboration with a few key Canadian companies, methods suitable for vehicle-mounted or fixed position applications and those suitable for person- or small robotportable roles have been studied. Vehicle-mounted systems mainly employ detection of characteristic radiation, whereas person-portable systems use imaging of back scattered radiation intensity distributions. Two key design tenets have been reduction of personnel shielding by the use of teleoperation and custom design of sensors to address the particular problem, rather than adapting an existing sensor to a problem. This is shown in a number of recent research examples. Among vehicle-mounted systems, recent research to improve the thermal neutron analysis (TNA) sensors, which were put into service with the Canadian Forces in 2002, are discussed. Research on fast neutron analysis (FNA) and associated particle imaging (API), which can augment or replace TNA, depending on the application, are described. Monoenergetic gamma ray induced photoneutron spectroscopy is a novel method which has a number of potential advantages and disadvantages over TNA and FNA. Sources, detectors and geometries have been identified and modelling studies have suggested feasibility. Among person-portable systems, research on neutron backscatter imaging and X-ray coded aperture backscatter imaging are discussed.

  20. Method of synthesizing bulk transition metal carbide, nitride and phosphide catalysts

    Science.gov (United States)

    Choi, Jae Soon; Armstrong, Beth L; Schwartz, Viviane

    2015-04-21

    A method for synthesizing catalyst beads of bulk transmission metal carbides, nitrides and phosphides is provided. The method includes providing an aqueous suspension of transition metal oxide particles in a gel forming base, dropping the suspension into an aqueous solution to form a gel bead matrix, heating the bead to remove the binder, and carburizing, nitriding or phosphiding the bead to form a transition metal carbide, nitride, or phosphide catalyst bead. The method can be tuned for control of porosity, mechanical strength, and dopant content of the beads. The produced catalyst beads are catalytically active, mechanically robust, and suitable for packed-bed reactor applications. The produced catalyst beads are suitable for biomass conversion, petrochemistry, petroleum refining, electrocatalysis, and other applications.

  1. Fabrication of Gd-Ba-Cu-O bulk superconductors with a cold seeding method

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, K. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan)]. E-mail: inouek@istec.or.jp; Sakai, N. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Murakami, M. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Shibaura Institute of Technology, 3-9-14 Shibaura, Minato-ku, Tokyo 105-0023 (Japan); Hirabayashi, I. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan)

    2005-10-01

    The target of an unmanned space experiment is the fabrication of large grain Gd-Ba-Cu-O superconductors 12 cm in diameter in microgravity environment. The advantage of the space experiment is the support of a huge sample by a seed crystal alone. For this experiment, the cold seeding (CS) method must be employed to meet the requirements of the space program. Although the CS method is easy to apply, it has been difficult to grow large grain samples because of a small temperature window for a stable crystal growth. We thus studied the heat schedules for the space experiment using a prototype ground experiment furnace, which is similar to the furnaces launched into space. We could find the melt growth conditions that enabled us to successfully grow Gd-Ba-Cu-O bulk superconductors 10 cm in diameter even by the CS method.

  2. Mercury speciation analysis in seafood by species-specific isotope dilution: method validation and occurrence data

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Stephanie; Guerin, Thierry [Agence Nationale de Securite Sanitaire de l' Alimentation, Laboratoire de Securite des Aliments de Maisons-Alfort, Unite des Contaminants Inorganiques et Mineraux de l' Environnement, ANSES, Maisons-Alfort (France); Monperrus, Mathilde; Donard, Olivier F.X.; Amouroux, David [IPREM UMR 5254 CNRS - Universite de Pau et des Pays de l' Adour, Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-chimie pour l' Environnement et les Materiaux, Pau Cedex (France)

    2011-11-15

    Methylmercury (MeHg) and total mercury (THg) in seafood were determined using species-specific isotope dilution analysis and gas chromatography combined with inductively coupled plasma mass spectrometry. Sample preparation methods (extraction and derivation step) were evaluated on certified reference materials using isotopically enriched Hg species. Solid-liquid extraction, derivation by propylation and automated agitation gave excellent accuracy and precision results. Satisfactory figures of merit for the selected method were obtained in terms of limit of quantification (1.2 {mu}g Hg kg{sup -1} for MeHg and 1.4 {mu}g Hg kg{sup -1} for THg), repeatability (1.3-1.7%), intermediate precision reproducibility (1.5% for MeHg and 2.2% for THg) and trueness (bias error less than 7%). By means of a recent strategy based on accuracy profiles ({beta}-expectation tolerance intervals), the selected method was successfully validated in the range of approximately 0.15-5.1 mg kg{sup -1} for MeHg and 0.27-5.2 mg kg{sup -1} for THg. Probability {beta} was set to 95% and the acceptability limits to {+-}15%. The method was then applied to 62 seafood samples representative of consumption in the French population. The MeHg concentrations were generally low (1.9-588 {mu}g kg{sup -1}), and the percentage of MeHg varied from 28% to 98% in shellfish and from 84% to 97% in fish. For all real samples tested, methylation and demethylation reactions were not significant, except in one oyster sample. The method presented here could be used for monitoring food contamination by MeHg and inorganic Hg in the future to more accurately assess human exposure. (orig.)

  3. Mercury speciation analysis in seafood by species-specific isotope dilution: method validation and occurrence data

    International Nuclear Information System (INIS)

    Methylmercury (MeHg) and total mercury (THg) in seafood were determined using species-specific isotope dilution analysis and gas chromatography combined with inductively coupled plasma mass spectrometry. Sample preparation methods (extraction and derivation step) were evaluated on certified reference materials using isotopically enriched Hg species. Solid-liquid extraction, derivation by propylation and automated agitation gave excellent accuracy and precision results. Satisfactory figures of merit for the selected method were obtained in terms of limit of quantification (1.2 μg Hg kg-1 for MeHg and 1.4 μg Hg kg-1 for THg), repeatability (1.3-1.7%), intermediate precision reproducibility (1.5% for MeHg and 2.2% for THg) and trueness (bias error less than 7%). By means of a recent strategy based on accuracy profiles (β-expectation tolerance intervals), the selected method was successfully validated in the range of approximately 0.15-5.1 mg kg-1 for MeHg and 0.27-5.2 mg kg-1 for THg. Probability β was set to 95% and the acceptability limits to ±15%. The method was then applied to 62 seafood samples representative of consumption in the French population. The MeHg concentrations were generally low (1.9-588 μg kg-1), and the percentage of MeHg varied from 28% to 98% in shellfish and from 84% to 97% in fish. For all real samples tested, methylation and demethylation reactions were not significant, except in one oyster sample. The method presented here could be used for monitoring food contamination by MeHg and inorganic Hg in the future to more accurately assess human exposure. (orig.)

  4. Towards bulk thermodynamics via non-equilibrium methods: gaseous methane as a case study.

    Science.gov (United States)

    Zerbetto, Mirco; Frezzato, Diego

    2015-01-21

    We illustrate how the Jarzynski equality (JE), which is the progenitor of non-equilibrium methods aimed at constructing free energy landscapes for molecular-sized fluctuating systems subjected to steered transformations, can be applied to derive equations of state for bulk systems. The key-step consists of physically framing the computational strategy of "total energy morphing", recently presented by us as an efficient implementation of the JE [M. Zerbetto, A. Piserchia, D. Frezzato, J. Comput. Chem., 2014, 35, 1865-1881], in terms of build-up of the real thermodynamic state of a bulk material from the corresponding ideal state, in which the particles are non-interacting. In this context, the JE machinery yields the excess free energy versus suitably chosen controlled state variables, whose thermodynamic derivatives eventually lead to the equation of state. As an explanatory case study, we apply the methodology to derive the equation of state of gaseous methane by constructing the Helmholtz free energy versus the particle density (at fixed temperature) and then evaluating the thermodynamic derivative with respect to the volume. In our intent, this "old-style" work on gaseous methane should open the way for the investigation of thermodynamics of extended systems via non-equilibrium methods. PMID:25475171

  5. Production of Sm–Fe–N bulk magnets by spark plasma sintering method

    International Nuclear Information System (INIS)

    Th2Zn17-type and TbCu7-type Sm–Fe–N powder were consolidated into bulk magnets by the spark plasma sintering (SPS) method. It was found that the coarse TbCu7-type Sm–Fe–N powder possessed greater stability during sintering than the fine Th2Zn17-type Sm–Fe–N powder. Although the TbCu7-type magnets produced at temperatures exceeding 773 K showed a low coercivity comparable to that of the Th2Zn17-type magnets, they exhibited a higher coercivity than the Th2Zn17-type magnets when produced at 773 K or lower. The TbCu7-type magnet produced at 773 K exhibited a high remanence of 96.4 Am2/kg with a high coercivity of 0.72 MA/m. - Highlights: • Sm–Fe–N powders were successfully consolidated into bulk magnets by the SPS method. • TbCu7-type powder was more stable than Th2Zn17-type powder during sintering. • The TbCu7-type magnets had higher density than the Th2Zn17-type magnets. • The TbCu7-type magnet produced at 773 K exhibited a high coercivity of 0.72 MA/m

  6. Kinetic spectrophotometric methods for the determination of dothiepin hydrochloride in bulk and in drug formulation.

    Science.gov (United States)

    Taha, Elham A

    2003-08-01

    Two simple and sensitive kinetic methods for the determination of dothiepin hydrochloride are described. The first method is based on kinetic investigation of the oxidation reaction of the drug with alkaline potassium permanganate at room temperature for a fixed time of 25 min. The absorbance of the colored manganate ions is measured at 610 nm. The second method is based on the reaction of dothiepin hydrochloride with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in the presence of 0.1 mol L(-1) sodium bicarbonate. Spectrophotometric measurement was achieved by recording the absorbance at 470 nm for a fixed time of 60 min. All variables affecting the development of the color were investigated and the conditions were optimized. Plots of absorbance against concentration in both procedures were rectilinear over the ranges 4-24 and 50-250 microg mL(-1), with mean recoveries 99.33+/-0.42 and 99.88+/-0.53, respectively. The proposed methods were successfully applied for the determination of dothiepin hydrochloride in bulk powder and in capsule dosage form. The results obtained were found to agree statistically with those given by the non-aqueous B.P. method. Furthermore the methods were validated according to USP guidelines and also assessed by applying the standard addition technique. The determination of dothiepin hydrochloride by the fixed concentration method is feasible with the calibration equations obtained, but the fixed time method proves to be more applicable. PMID:12856096

  7. Method optimization and quality assurance in speciation analysis using high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Larsen, Erik H.

    1998-02-01

    Achievement of optimum selectivity, sensitivity and robustness in speciation analysis using high performance liquid chromatography (HPLC) with inductively coupled mass spectrometry (ICP-MS) detection requires that each instrumental component is selected and optimized with a view to the ideal operating characteristics of the entire hyphenated system. An isocratic HPLC system, which employs an aqueous mobile phase with organic buffer constituents, is well suited for introduction into the ICP-MS because of the stability of the detector response and high degree of analyte sensitivity attained. Anion and cation exchange HPLC systems, which meet these requirements, were used for the seperation of selenium and arsenic species in crude extracts of biological samples. Furthermore, the signal-to-noise ratios obtained for these incompletely ionized elements in the argon ICP were further enhanced by a factor of four by continously introducing carbon as methanol via the mobile phase into the ICP. Sources of error in the HPLC system (column overload), in the sample introduction system (memory by organic solvents) and in the ICP-MS (spectroscopic interferences) and their prevention are also discussed. The optimized anion and cation exchange HPLC-ICP-MS systems were used for arsenic speciation in contaminated ground water and in an in-house shrimp reference sample. For the purpose of verification, HPLC coupled with tandem mass spectrometry with electrospray ionization was additionally used for arsenic speciation in the shrimp sample. With this analytical technique the HPLC retention time in combination with mass analysis of the molecular ions and their collision-induced fragments provide almost conclusive evidence of the identity of the analyte species. The speciation methods are validated by establishing a mass balance of the analytes in each fraction of the extraction procedure, by recovery of spikes and by employing and comparing independent techniques. The urgent need for

  8. A novel fast gas chromatography method for higher time resolution measurements of speciated monoterpenes in air

    Science.gov (United States)

    Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

    2014-05-01

    Biogenic emissions supply the largest fraction of non-methane volatile organic compounds (VOC) from the biosphere to the atmospheric boundary layer, and typically comprise a complex mixture of reactive terpenes. Due to this chemical complexity, achieving comprehensive measurements of biogenic VOC (BVOC) in air within a satisfactory time resolution is analytically challenging. To address this, we have developed a novel, fully automated Fast Gas Chromatography (Fast-GC) based technique to provide higher time resolution monitoring of monoterpenes (and selected other C9-C15 terpenes) during plant emission studies and in ambient air. To our knowledge, this is the first study to apply a Fast-GC based separation technique to achieve quantification of terpenes in ambient air. Three chromatography methods have been developed for atmospheric terpene analysis under different sampling scenarios. Each method facilitates chromatographic separation of selected BVOC within a significantly reduced analysis time compared to conventional GC methods, whilst maintaining the ability to quantify individual monoterpene structural isomers. Using this approach, the C9-C15 BVOC composition of single plant emissions may be characterised within a 14.5 min analysis time. Moreover, in-situ quantification of 12 monoterpenes in unpolluted ambient air may be achieved within an 11.7 min chromatographic separation time (increasing to 19.7 min when simultaneous quantification of multiple oxygenated C9-C10 terpenoids is required, and/or when concentrations of anthropogenic VOC are significant). These analysis times potentially allow for a twofold to fivefold increase in measurement frequency compared to conventional GC methods. Here we outline the technical details and analytical capability of this chromatographic approach, and present the first in-situ Fast-GC observations of 6 monoterpenes and the oxygenated BVOC (OBVOC) linalool in ambient air. During this field deployment within a suburban forest

  9. Comparison of methods for inorganic sulfur speciation in a petroleum production effluent

    International Nuclear Information System (INIS)

    Multiple analytical techniques were compared for identification and quantification of inorganic sulfur species present in a sulfidic waste effluent (produced water) generated during offshore oil production. Inorganic sulfur species including sulfide, polysulfides, thiosulfate, sulfite, and sulfate were measured in produced water samples using sampled direct current polarography, differential pulse polarography, iodometry, spectrophotometry after derivatization with Ellman's reagent, high-performance liquid chromatography after derivatization with 2,2'-dithiobis(5-nitropyridine), and barium chloride precipitation of sulfate. Sulfide was determined in seven produced water samples at concentrations of 1 to 8 mM, as well as sulfate, polysulfides, and thiosulfate; sulfite was detected only occasionally in lower concentrations. Comparison of four methods used for sulfide measurement demonstrated systematic differences in results generated by various methods. Measurements of inorganic sulfur species in produced water are influenced by coupled equilibria between different chemical forms. Polysulfides exert an important role in coupling reactions between sulfur in intermediate oxidation states, and their presence can affect quantitation of these species when physical separations or standard additions perturb solution equilibria

  10. Speciation of hydroxy-aluminum solutions by wet chemical and aluminum-27 NMR methods

    International Nuclear Information System (INIS)

    Partially neutralized Al solutions with OH/Al molar (n∼) ratios ranging from 0.25 to 2.5 were studied employing 27Al nuclear magnetic resonance spectroscopy and the ferron-timed colorimetric assay. The monomeric Al concentrations (Al/sub a/) estimated by the ferron assay were consistently higher than the actual concentration determined by NMR spectroscopy. The differences between the methods indicate the presence of a small polymer which reacts rapidly with ferron and is erroneously assigned to the monomeric Al fraction. The polymeric Al component (Al/sub b/) estimated by the ferron method could be partitioned into a more rapidly reacting fraction (∂1 h) and a slowly reacting fraction (> 1 h). The amount of Al associated with the rapidly reacting polymeric fraction corresponded to the amount of [AlO4 Al12(OH)24(H2O)12]7+ polymer directly determined by NMR spectroscopy. The slower reacting component of the Al/sub b/ fraction is believed to be a polymer of the hexameric ring morphology. Direct NMR measurements provided evidence for specific adsorption of Al13 to a cation exchange resin and differential precipitation kinetics of this polymer with added sulfate. These data indicate that characterizing hydroxy Al solutions without direct measurements can lead to erroneous interpretations concerning the distribution between monomeric and polymeric Al and the nature and types of polymeric Al present

  11. Flux pinning properties of impurity doped MgB2 bulks synthesized by diffusion method

    International Nuclear Information System (INIS)

    Doping effects of carbon-containing impurities on the critical current properties and microstructure were systematically studied for highly dense MgB2 bulks prepared by the diffusion method starting from magnesium and boron which are separately packed in sealed stainless tubes. Obtained samples exhibited improved critical current density, J c, simply by an increase of effective current pass. A non-doped MgB2 recorded almost double high J c at 20 K compared with those of the conventional porous MgB2 bulks having ∼50% of the theoretical density, while irreversibility field, H irr, did not largely change. J c under high magnetic fields were enhanced by doping of carbon-containing impurities, such as SiC and B4C. Optimal doping levels of SiC and B4C for high critical current properties at 20 K are found to be ∼2% and 5%, respectively, as nominal carbon concentration at boron site. Difference in the optimal doping levels is originated from the difference in their reactivity

  12. RP-HPLC Method Development and Validation of Abacavir Sulphate in Bulk and Tablet Dosage Form

    Directory of Open Access Journals (Sweden)

    S. LAVANYA

    2014-11-01

    Full Text Available RP-HPLC method was developed for the estimation of abacavir sulphate in bulk and pharmaceutical dosage form (tablets by using INERTSIL ODS 3V column, C18 (250x4.6 ID mobile phase consisting of a mixture of 10mM phosphate buffer: ACN (60:40 v/v % PH: 4.0 with detection of 287 nm. The retention time was found to be 2.430min and linearity was observed in the range 60-140μg /ml. Still now there were a number of analytical methods were developed for the estimation of abacavir in pharmaceutical dosage form and also in biological samples like spectroscopic methods, chromatographic methods, etc. But the present method was met the validation parameters according ICH guidelines like accuracy, precision, linearity, range, robustness, ruggedness, limit of detection and limit of quantitation, etc. with a short around time. The method was found to be precise as indicated by the repeatability analysis, showing %RSD less than 2.

  13. Uranium theoretical speciation for drinking water from private drilled wells in Sweden – Implications for choice of removal method

    International Nuclear Information System (INIS)

    Highlights: • Neutral charge uranium complexes dominated in the pH range 6.7–7.8. • The Ca concentration influence which calcium-UO2 carbonate complexes was formed. • In the acidic pH range several different U complexes can comprise a large fraction of total complexes. • It is crucial to include all relevant chemical compounds in the model. • Before removal method is selected, some crucial parameters should be measured. - Abstract: Elevated concentrations of uranium (U) from natural sources have been measured in drinking water from private drilled wells in Sweden and many other countries world-wide. Although U is a radioactive element, radioactivity is not the main concern, but rather chemical toxicity, e.g. kidney damage. Uranium chemistry is complex and U in water has a very high tendency to form complexes with other compounds. Since speciation is crucial for the properties of U, and therefore the removal efficiency, this study determined theoretical U species in drinking water from private drilled wells using the geochemical model Visual MINTEQ. The drinking water samples used in modelling were from two datasets: (1) 76 water samples selected from a previous survey of 722 wells; and (2) samples of drinking water from 21 private wells sampled in May 2013. The results showed that neutrally charged U complexes dominated in the pH range 6.7–7.8, which is common in private drilled wells. This has important implications for removal method, since charge is an important factor for U removal efficiency. In the alkaline pH range, one of two calcium-UO2 carbonate complexes dominated and calcium (Ca) concentration proved to be a key factor determining the Ca-UO2 carbonate complex formed: the neutral Ca2UO2(CO3)30(aq) or the negative CaUO2(CO3)32−. Complexes with organic carbon (C) varied greatly in the acidic range, indicating that it is crucial to measure organic C content in the water since it is critical for the dissolved organic matter (DOM)-UO2 complex

  14. Speciation analysis of radionuclides in the environment. NKS-B speciation project report 2007

    Energy Technology Data Exchange (ETDEWEB)

    Xiaolin Hou (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Aldahan, A. (Uppsala Univ., Dept. of Earth Science, Uppsala (Sweden)); Possnert, G. (Uppsala Univ., Tandem Lab., Uppsala (Sweden)); Lujaniene, G. (Institute of Physics, Vilnius (Lithuania)); Lehto, J. (Univ. of Helsinki, Dept. of Chemistry, Helsinki (Finland)); Salbu, B. (Norwegian Univ. of Life Sciences (UMB), AAs (Norway))

    2008-07-15

    This report describes the work carried out under the NUK-B project SPECIATION 2007. In 2007, the project partners had two meeting in April and November, organized a NUK seminar on speciation and hot particles. SPECIATION 2007 t mainly focused on two issues on speciation (1) further development of speciation methods for radionuclides, and (2) investigation of speciation of radionuclides in environment. The report summarized the work done in partners labs, which includes: (1) Further development on the speciation of 129I and 127I in water samples; (2) Speciation method for 129I and 127I in air; (3) Dynamic system for fractionation of Pu and Am in soil and sediment; (4) Investigation on Re-absorption of Pu during the fractionation of Pu in soil and sediment; (5) Speciation of 129I in North Sea surface water; (6) Partition of 137Cs and 129I in the Nordic lake sediment, pore-water and lake water; (7) Sequential extraction of Pu in soil, sediment and concrete samples, (8) Pu sorption to Mn and Fe oxides in the geological materials, (10) Investigation of the adsorbed species of lanthanides and actinides on clays surfaces. In addition, two review articles on the speciation of plutonium and iodine in environmental are planned to be submitted to an international journal for publication. (au)

  15. Speciation analysis of radionuclides in the environment. NKS-B speciation project report 2007

    International Nuclear Information System (INIS)

    This report describes the work carried out under the NUK-B project SPECIATION 2007. In 2007, the project partners had two meeting in April and November, organized a NUK seminar on speciation and hot particles. SPECIATION 2007 t mainly focused on two issues on speciation (1) further development of speciation methods for radionuclides, and (2) investigation of speciation of radionuclides in environment. The report summarized the work done in partners labs, which includes: (1) Further development on the speciation of 129I and 127I in water samples; (2) Speciation method for 129I and 127I in air; (3) Dynamic system for fractionation of Pu and Am in soil and sediment; (4) Investigation on Re-absorption of Pu during the fractionation of Pu in soil and sediment; (5) Speciation of 129I in North Sea surface water; (6) Partition of 137Cs and 129I in the Nordic lake sediment, pore-water and lake water; (7) Sequential extraction of Pu in soil, sediment and concrete samples, (8) Pu sorption to Mn and Fe oxides in the geological materials, (10) Investigation of the adsorbed species of lanthanides and actinides on clays surfaces. In addition, two review articles on the speciation of plutonium and iodine in environmental are planned to be submitted to an international journal for publication. (au)

  16. Validated LC method for the estimation of voriconazole in bulk and formulation

    Directory of Open Access Journals (Sweden)

    Patel C

    2009-01-01

    Full Text Available Reversed phase high performance liquid chromatographic method was developed and validated for the estimation of voriconazole in bulk and formulation using prominence diode array detector. Selected mobile phase was a combination of water:acetonitrile (35:65 % v/v and wavelength selected was 256 nm. Retention time of voriconazole was 3.95 min. Linearity of the method was found to be 0.1 to 2 µg/ml, with the regression coefficient of 0.999. This method was validated according to ICH guidelines. Quantification was done by calculating area of the peak and the detection limit and quantitation limit ware 0.026 µg/ml and 0.1 µg/ml, respectively. There was no significant difference in the intra day and inter day analysis of voriconazole determined for three different concentrations using this method. Present method can be applied for the determination of voriconazole in quality control of formulation without interference of the excipients.

  17. Validated LC Method for the Estimation of Voriconazole in Bulk and Formulation.

    Science.gov (United States)

    Patel, C N; Dave, J B; Patel, J V; Panigrahi, B

    2009-11-01

    Reversed phase high performance liquid chromatographic method was developed and validated for the estimation of voriconazole in bulk and formulation using prominence diode array detector. Selected mobile phase was a combination of water:acetonitrile (35:65 % v/v) and wavelength selected was 256 nm. Retention time of voriconazole was 3.95 min. Linearity of the method was found to be 0.1 to 2 mug/ml, with the regression coefficient of 0.999. This method was validated according to ICH guidelines. Quantification was done by calculating area of the peak and the detection limit and quantitation limit ware 0.026 mug/ml and 0.1 mug/ml, respectively. There was no significant difference in the intra day and inter day analysis of voriconazole determined for three different concentrations using this method. Present method can be applied for the determination of voriconazole in quality control of formulation without interference of the excipients. PMID:20376229

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

    Directory of Open Access Journals (Sweden)

    Anindita Behera

    2011-01-01

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

  19. A comparative study of bulk etch rate measurement methods in polycarbonate detectors

    International Nuclear Information System (INIS)

    The response of a plastic detector to an incoming charged particle is given by the ratio of track etch rate vt to bulk etch rate vg along its path. Although the accurate determination of vt offers no difficulty as cone length can be comfortably measured, there seems to be a certain ambiguity as how to measure vg. Several LEXAN and TUFFAK polycarbonate plates have been exposed to normally incident Californium-252 fission fragments, etched in a stirred aqueous NaOH solution saturated with etch products and with a 0.05% of Dowfax surfactant, for different etching times, concentrations and temperatures. We have used three methods to measure vg and we obtain consistent results in agreement with those published in the literature. Surface quality and, consequently, ellipses neatness, are far superior in TUFFAK than in LEXAN. (author)

  20. An efficient hybrid conventional method to fabricate nacre-like bulk nano-laminar composites

    International Nuclear Information System (INIS)

    Bulk nano-laminar composites were fabricated by a novel technique called Hot-press Assisted Slip Casting (HASC) which combines hot-pressing and slip-casting to improve alignment and volume fraction of the reinforcement. Alumina flakes were used as filler in an epoxy matrix. Microstructure of composites and alignment of flakes were characterized by Scanning Electron Microscope (SEM). Three point bending test and Vickers hardness test were done for mechanical characterization of composites. Flexural tests on Chevron-notched specimens revealed a high work-of-fracture in the case of the fabricated composites reaching to 254 J/m2. Fracture surface of three point bending samples were examined by SEM. Main fracture mechanism is debonding of flakes from the matrix. With its high volume fraction (60%) of reinforcement phase and high degree of flake alignment, a nacre-like microstructure was achieved with a relatively efficient, cost effective and simple hybrid conventional method.

  1. Bulk Al/SiC nanocomposite prepared by ball milling and hot pressing method

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li

    2006-01-01

    Nano-sized Al/SiC powders were prepared by mechanical alloying method. Two sorts of SiC particle,i.e.,nano-sized and popular micron-sized SiC were utilized. The particle size and microstructure of the milled powder were characterised. Effects of the particle size and agglomerate state of SiC,as well as the microstructure of Al/SiC nanocomposite were studied by SEM and TEM. The results show that nano-sized SiC particles is dispersed in aluminium uniformly after ball milled for only 2 h,whereas the similar process need about 10 h for popular micron-sized SiC particle. The bulk Al/SiC nanocomposite can be fabricated by hot pressing the nano-sized Al/SiC powders at temperature about 723 K under pressure of 100 MPa.

  2. Comparison of two experimental speciation methods with a theoretical approach to monitor free and labile Cd fractions in soil solutions

    International Nuclear Information System (INIS)

    This work focused on the suitability of two techniques to monitor cadmium speciation in soil solutions collected during a 7-day incubation of a contaminated soil. Anodic stripping voltammetry (ASV) and ion exchange were performed on soil solutions collected daily and results were compared with calculations obtained with the speciation software Visual MINTEQ. The electrochemically labile Cd fraction was greater than the exchange-estimated free Cd fraction during the first 6 days, after which it decreased sharply during the last 2 days to reach values close to the exchange-estimated free Cd fraction. Further investigations showed that the increase in pH was mainly responsible for the reduction. However, calculations performed with Visual MINTEQ software clearly demonstrated that a change in the nature of organic matter and/or its complexing capacity also needed to be taken into consideration.

  3. Separation/Preconcentration and Speciation Analysis of Trace Amounts of Arsenate and Arsenite in Water Samples Using Modified Magnetite Nanoparticles and Molybdenum Blue Method

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Karimi

    2014-01-01

    Full Text Available A new, simple, and fast method for the separation/preconcentration and speciation analysis of arsenate and arsenite ions using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs followed by molybdenum blue method is proposed. The method is based on the adsorption of arsenate on CTAB@ACMNPs. Total arsenic in different samples was determined as As(V after oxidation of As(III to As(V using potassium permanganate. The arsenic concentration has been determined by UV-Visible spectrometric technique based on molybdenum blue method and amount of As(III was calculated by subtracting the concentration of As(V from total arsenic concentration. MNPs and ACMNPs were characterized by VSM, XRD, SEM, and FT-IR spectroscopy. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range, and relative standard deviation (RSD of arsenate were 175 (for 350 mL of sample solution, 0.028 μg mL−1, 0.090–4.0 μg mL−1, and 2.8% (for 2.0 μg mL−1, n=7, respectively. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. The proposed method was successfully applied to the determination and speciation of arsenic in different water samples and suitable recoveries were obtained.

  4. Speciation analysis of radionuclides in the environment - NSK-B SPECIATION project report 2009

    International Nuclear Information System (INIS)

    The second stage of the NKS-B project SPECIATION was complemented in 2008-2009, which mainly focus on three aspects: (1) Further improvement and development of methods for speciation analysis of radionuclides; (2) Investigation of speciation of some radionuclides in the environment (water, sediments, particles); and (3) Intercomparison excise for speciation analysis of radionuclides in soil and sediment. This report summarizes the work completed in the project partners' laboratories. Method developments include: Development of an rapid and in-suit separation method for the speciation analysis of 129I in seawater samples; Development of a simple method for the speciation analysis of 129I in fresh water and seawater samples; Development of an on-line HPLC-ICP-MS method for the direct speciation analysis of 127I in water and leachate samples; Speciation of radionuclides in water includes: Speciation of 129I and 127I in time-series precipitation samples collected in Denmark 2001-2006 and its application for the investigation of geochemistry and atmospheric chemistry of iodine, Speciation of radionuclides in Ob and Yenisey Rivers, and Speciation of 129I and 127I in Lake Heimdalen water. Speciation of radionuclides in soils and sediments includes: Sequential extraction of radionuclides in sediments and of trace elements in soil samples. Sequential extraction of radionuclides in aerosols and particles has also been performed. Furthermore, sorption experiments have been performed to investigate the association of Pu, Am and Cs with different geological materials. The intercomparison exercises included sequential extraction of Pu, 137Cs, U, Th, and 129I in one soil and one sediment standard reference materials (NIST-4354, IAEA-375) and Pu in sediment collected from the Lake Heimdalen, Norway. (author)

  5. Speciation analysis of radionuclides in the environment - NSK-B SPECIATION project report 2009

    Energy Technology Data Exchange (ETDEWEB)

    Hou, X. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Aldahan, A. (Uppsala Univ., Dept. of Earth Science (Sweden)); Possnert, G. (Uppsala Univ., Tandem Lab. (Sweden)); Lujaniene, G. (Univ. of Helsinki, Lab. of Radiochemistry (Finland)); Lehto, J. (Institute of Physics (Lithuania)); Skipperud, L.; Lind, O.C.; Salbu, B. (Norwegian Univ. of Life Sciences, Isotope Lab., AAs (Norway))

    2009-10-15

    The second stage of the NKS-B project SPECIATION was complemented in 2008-2009, which mainly focus on three aspects: (1) Further improvement and development of methods for speciation analysis of radionuclides; (2) Investigation of speciation of some radionuclides in the environment (water, sediments, particles); and (3) Intercomparison excise for speciation analysis of radionuclides in soil and sediment. This report summarizes the work completed in the project partners' laboratories. Method developments include: Development of an rapid and in-suit separation method for the speciation analysis of 129I in seawater samples; Development of a simple method for the speciation analysis of 129I in fresh water and seawater samples; Development of an on-line HPLC-ICP-MS method for the direct speciation analysis of 127I in water and leachate samples; Speciation of radionuclides in water includes: Speciation of 129I and 127I in time-series precipitation samples collected in Denmark 2001-2006 and its application for the investigation of geochemistry and atmospheric chemistry of iodine, Speciation of radionuclides in Ob and Yenisey Rivers, and Speciation of 129I and 127I in Lake Heimdalen water. Speciation of radionuclides in soils and sediments includes: Sequential extraction of radionuclides in sediments and of trace elements in soil samples. Sequential extraction of radionuclides in aerosols and particles has also been performed. Furthermore, sorption experiments have been performed to investigate the association of Pu, Am and Cs with different geological materials. The intercomparison exercises included sequential extraction of Pu, 137Cs, U, Th, and 129I in one soil and one sediment standard reference materials (NIST-4354, IAEA-375) and Pu in sediment collected from the Lake Heimdalen, Norway. (author)

  6. Simultaneous Estimation of Minoxidil and Aminexil in Bulk and Pharmaceutical Formulations by Rp-Hplc Method

    Directory of Open Access Journals (Sweden)

    Iffath Rizwana

    2015-03-01

    Full Text Available new, simple, precise, accurate and reproducible RP-HPLC method for simultaneous estimation of minoxidil and aminexil in bulk and pharmaceutical formulations. Separation of minoxidil and aminexil was successfully achieved on a Agilent C18 (150 mm x 4.6 mm x 5µ Make: Waters or equivalent in an isocratic mode utilizing 0.1% orthophosphoric acid and methanol in the ratio of 60:40 v/v at a flowrate of 1 ml/min. The developed method was found to be linear in the concentration range of 50µg/ml to 150 µg/ml for minoxidil and 50 µg/ml to 150 µg/ml for aminexil. The value of the correlation coefficient was found to be 0.999 for both minoxidil and aminexil. The LOD and LOQ for aminexil were found to be 0.0146 and 0.0486 mg/ml, respectively, where as for minoxidil the values are 0.046 mg/ml and 0.155 mg/ml, respectively. This method was found to be good percentage recovery for minoxidil and aminexil were found to be 99.00 and 100.00, respectively indicates that the proposed method is sufficiently accurate. The specificity of the method shows good correlation between retention times of standard with the sample. Therefore, the method specifically determines the analyte in the sample without interference from excipients that are commonly present in the pharmaceutical dosage forms. The method was validated according to ICH guidelines for linearity, range, accuracy, precesion, specificity and robustness.

  7. Structure and magnetism of bulk Fe and Cr: from plane waves to LCAO methods

    International Nuclear Information System (INIS)

    Magnetic, structural and energetic properties of bulk Fe and Cr were studied using first-principles calculations within density functional theory (DFT). We aimed to identify the dependence of these properties on key approximations of DFT, namely the exchange-correlation functional, the pseudopotential and the basis set. We found a smaller effect of pseudopotentials (PPs) on Fe than on Cr. For instance, the local magnetism of Cr was shown to be particularly sensitive to the potentials representing the core electrons, i.e. projector augmented wave and Vanderbilt ultrasoft PPs predict similar results, whereas standard norm-conserving PPs tend to overestimate the local magnetic moments of Cr in bcc Cr and in dilute bcc FeCr alloys. This drawback is suggested to be closely correlated to the overestimation of Cr solution energy in the latter system. On the other hand, we point out that DFT methods with very reduced localized basis sets (LCAO: linear combination of atomic orbitals) give satisfactory results compared with more robust plane-wave approaches. A minimal-basis representation of '3d' electrons comes to be sufficient to describe non-trivial magnetic phases including spin spirals in both fcc Fe and bcc Cr, as well as the experimental magnetic ground state of bcc Cr showing a spin density wave (SDW) state. In addition, a magnetic 'spd' tight binding model within the Stoner formalism was proposed and validated for Fe and Cr. The respective Stoner parameters were obtained by fitting to DFT data. This efficient semiempirical approach was shown to be accurate enough for studying various collinear and non-collinear phases of bulk Fe and Cr. It also enabled a detailed investigation of different polarization states of SDW in bcc Cr, where the longitudinal state was suggested to be the ground state, consistent with existing experimental data.

  8. Structure and magnetism of bulk Fe and Cr: from plane waves to LCAO methods.

    Science.gov (United States)

    Soulairol, R; Fu, Chu-Chun; Barreteau, C

    2010-07-28

    Magnetic, structural and energetic properties of bulk Fe and Cr were studied using first-principles calculations within density functional theory (DFT). We aimed to identify the dependence of these properties on key approximations of DFT, namely the exchange-correlation functional, the pseudopotential and the basis set. We found a smaller effect of pseudopotentials (PPs) on Fe than on Cr. For instance, the local magnetism of Cr was shown to be particularly sensitive to the potentials representing the core electrons, i.e. projector augmented wave and Vanderbilt ultrasoft PPs predict similar results, whereas standard norm-conserving PPs tend to overestimate the local magnetic moments of Cr in bcc Cr and in dilute bcc FeCr alloys. This drawback is suggested to be closely correlated to the overestimation of Cr solution energy in the latter system. On the other hand, we point out that DFT methods with very reduced localized basis sets (LCAO: linear combination of atomic orbitals) give satisfactory results compared with more robust plane-wave approaches. A minimal-basis representation of '3d' electrons comes to be sufficient to describe non-trivial magnetic phases including spin spirals in both fcc Fe and bcc Cr, as well as the experimental magnetic ground state of bcc Cr showing a spin density wave (SDW) state. In addition, a magnetic 'spd' tight binding model within the Stoner formalism was proposed and validated for Fe and Cr. The respective Stoner parameters were obtained by fitting to DFT data. This efficient semiempirical approach was shown to be accurate enough for studying various collinear and non-collinear phases of bulk Fe and Cr. It also enabled a detailed investigation of different polarization states of SDW in bcc Cr, where the longitudinal state was suggested to be the ground state, consistent with existing experimental data. PMID:21399309

  9. Structure and magnetism of bulk Fe and Cr: from plane waves to LCAO methods

    Energy Technology Data Exchange (ETDEWEB)

    Soulairol, R; Fu, Chu-Chun [CEA, DEN, Service de Recherches de Metallurgie Physique, F-91191 Gif-sur-Yvette (France); Barreteau, C, E-mail: chuchun.fu@cea.f [CEA Saclay, DSM/DRECAM/SPCSI, Batiment 462, F-91191 Gif-sur-Yvette (France)

    2010-07-28

    Magnetic, structural and energetic properties of bulk Fe and Cr were studied using first-principles calculations within density functional theory (DFT). We aimed to identify the dependence of these properties on key approximations of DFT, namely the exchange-correlation functional, the pseudopotential and the basis set. We found a smaller effect of pseudopotentials (PPs) on Fe than on Cr. For instance, the local magnetism of Cr was shown to be particularly sensitive to the potentials representing the core electrons, i.e. projector augmented wave and Vanderbilt ultrasoft PPs predict similar results, whereas standard norm-conserving PPs tend to overestimate the local magnetic moments of Cr in bcc Cr and in dilute bcc FeCr alloys. This drawback is suggested to be closely correlated to the overestimation of Cr solution energy in the latter system. On the other hand, we point out that DFT methods with very reduced localized basis sets (LCAO: linear combination of atomic orbitals) give satisfactory results compared with more robust plane-wave approaches. A minimal-basis representation of '3d' electrons comes to be sufficient to describe non-trivial magnetic phases including spin spirals in both fcc Fe and bcc Cr, as well as the experimental magnetic ground state of bcc Cr showing a spin density wave (SDW) state. In addition, a magnetic 'spd' tight binding model within the Stoner formalism was proposed and validated for Fe and Cr. The respective Stoner parameters were obtained by fitting to DFT data. This efficient semiempirical approach was shown to be accurate enough for studying various collinear and non-collinear phases of bulk Fe and Cr. It also enabled a detailed investigation of different polarization states of SDW in bcc Cr, where the longitudinal state was suggested to be the ground state, consistent with existing experimental data.

  10. Bulk Synthesis and Characterization of Ti3Al Nanoparticles by Flow-Levitation Method

    Directory of Open Access Journals (Sweden)

    Shanjun Chen

    2013-01-01

    Full Text Available A novel bulk synthesis method for preparing high pure Ti3Al nanoparticles was developed by flow-levitation method (FL. The Ti and Al vapours ascending from the high temperature levitated droplet were condensed by cryogenic Ar gas under atmospheric pressure. The morphology, crystalline structure, and chemical composition of Ti3Al nanoparticles were, respectively, investigated by transmission electron microscopy, X-ray diffraction, and inductively coupled plasma atomic emission spectrometry. The results indicated that the Ti3Al powders are nearly spherical-shaped, and the particle size ranges from several nanometers to 100 nm in diameter. Measurements of the d-spacing from X-ray (XRD and electron diffraction studies confirmed that the Ti3Al nanoparticles have a hexagonal structure. A thin oxidation coating of 2-3 nm in thickness was formed around the particles after exposure to air. Based on the XPS measurements, the surface coating of the Ti3Al nanoparticles is a mixture of Al2O3 and TiO2. The production rate of Ti3Al nanoparticles was estimated to be about 3 g/h. This method has a great potential in mass production of Ti3Al nanoparticles.

  11. Molecular Dynamics Study of a Thermal Expansion Coefficient: Ti Bulk with an Elastic Minimum Image Method

    Institute of Scientific and Technical Information of China (English)

    Yakup Hundur; Rainer Hippler; Ziya B. Güven(c)

    2006-01-01

    @@ Linear thermal expansion coefficient (TEC) of Ti bulk is investigated by means of molecular dynamics simulation.The elastic minimum image convention of periodic boundary conditions is introduced to allow the bulk to adjust its size according to the new fixed temperature. The TEC and the specific heat of Ti are compared to the available theoretical and experimental data.

  12. Experimental Design Optimization of a Sequential Injection Method for Promazine Assay in Bulk and Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    Salah M. Sultan

    2007-11-01

    Full Text Available Experimental design optimization approach was utilized to develop a sequential injection analysis (SIA method for promazine assay in bulk and pharmaceutical formulations. The method was based on the oxidation of promazine by Ce(IV in sulfuric acidic media resulting in a spectrophotometrically detectable species at 512 nm. A 33 full factorial design and response surface methods were applied to optimize experimental conditions potentially controlling the analysis. The optimum conditions obtained were 1.0×10−4 M sulphuric acid, 0.01 M Ce(IV, and 10 μL/s flow rate. Good analytical parameters were obtained including range of linearity 1–150 μg/mL, linearity with correlation coefficient 0.9997, accuracy with mean recovery 98.2%, repeatability with RSD 1.4% (n=7 consequent injections, intermediate precision with RSD 2.1% (n=5 runs over a week, limits of detection 0.34 μg/mL, limits of quantification 0.93 μg/mL, and sampling frequency 23 samples/h. The obtained results were realized by the British Pharmacopoeia method and comparable results were obtained. The provided SIA method enjoys the advantages of the technique with respect to rapidity, reagent/sample saving, and safety in solution handling and to the environment.

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

    Directory of Open Access Journals (Sweden)

    Kareti Srinivasa Rao

    2011-01-01

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

  14. A Validated HPTLC Method for Simultaneous Quantification of Nebivolol and Hydrochlorothiazide in Bulk and Tablet Formulation

    Directory of Open Access Journals (Sweden)

    S. T. Kumbhar

    2011-01-01

    Full Text Available A HPTLC method for the estimation of Nebivolol (NBV and Hydrochlorothiazide (HCTZ has been developed. It employs aluminum backed silica gel 60 F254 TLC plates, (20 cm × 10 cm, layer thickness 0.2 mm pre-washed with methanol and mobile phase comprising of 1,4-dioxane: toluene: triethylamine (5:3:0.1 v/v. The developing solvent was run up to 80 mm in Camag chamber previously saturated with 10.0 ml of solvent mixture for 30 min. Densitometric scanning was then performed with Camag TLC Scanner-3 equipped with winCATS (version 1.3.0 at λ max 281 nm. The Rf values were found to be 0.75 and 0.43 for Nebivolol and Hydrochlorothiazide respectively. The limit of detection and limit of quantitation were found to be 43ng/spot & 130ng/spot for Nebivolol and 25ng/spot & 76ng/spot for Hydrochlorothiazide respectively. The % RSD of intra-day variation and inter day variation were 0.54 and 0.41 respectively for NBV and 0.46 and 0.39 for HCTZ respectively. The proposed method can also be used for routine quality control to accurately determine Nebivolol and Hydrochlorothiazide in bulk and tablet dosage form.

  15. New Simple UV Spectrophotometric Method for Determination of Mirtazapine in Bulk and pharmaceutical dosage forms

    Directory of Open Access Journals (Sweden)

    Sk. Benajeer

    2012-10-01

    Full Text Available Mirtazapine is chemically a tetratetracyclic (pyridodibenzazepine derivative which is classified as a noradrenergic and specific serotonergic antidepressant (NaSSA. Mirtazapine acts as an antagonist at central pre-synaptic α2-receptors, inhibiting negative feedback to the presynaptic nerve and causing an increase in NErelease. It is also used for the treatment of Posttraumatic stress disorder. In present work, simple, sensitive, accurate and economical spectroscopic method has been developed for the estimation of mirtazapine in bulk and its pharmaceutical dosage forms. An absorption maximum was found to be at 232nm with the solvent systemphosphate buffer (pH 6.8. The drug follows beer’s law in the range of 5-30μg/ml with correlation coefficient of 0.999. The percentage recovery of mirtazapine ranged from 99.57-100.26% in pharmaceutical dosage form. Results of the analysis were validated for accuracy, precision, LOD, LOQ and were found to be satisfactory. The proposed method is simple, rapid and suitable for the routine quality control analysis.

  16. Repetitive forging (RF) using inclined punches as a new bulk severe plastic deformation method

    International Nuclear Information System (INIS)

    A new bulk severe plastic deformation method based on repetitive forging (RF) using inclined punches is proposed. This process consists of two half cycles. In the first half cycle, a square cross section deforms to parallelogram by forging with two inclined punches, and the parallelogram cross section is forged back to square using two flat punches in the second half cycle. This method was applied to commercially pure copper and significant grain refinement was achieved after four passes of RF. The results showed that significant improvement in the mechanical properties was obtained. Notable increase of yield and ultimate strengths corresponding to 358 MPa and 381 MPa after four passes of RF from the initial values of 121 MPa and 230.5 MPa is detectable. Microhardness increases to about 100 Hv after four passes of RF from the initial value of 53 Hv. Finite element (FE) results illustrate that RF is able to impose extremely high plastic strains to the materials. In the RF process, the processed samples have the same dimensions and geometry as those of the initial sample without any waste material and there is no need for back pressure.

  17. Iodine speciation in coastal and inland bathing waters and seaweeds extracts using a sequential injection standard addition flow-batch method.

    Science.gov (United States)

    Santos, Inês C; Mesquita, Raquel B R; Bordalo, Adriano A; Rangel, António O S S

    2015-02-01

    The present work describes the development of a sequential injection standard addition method for iodine speciation in bathing waters and seaweeds extracts without prior sample treatment. Iodine speciation was obtained by assessing the iodide and iodate content, the two inorganic forms of iodine in waters. For the determination of iodide, an iodide ion selective electrode (ISE) was used. The indirect determination of iodate was based on the spectrophotometric determination of nitrite (Griess reaction). For the iodate measurement, a mixing chamber was employed (flow batch approach) to explore the inherent efficient mixing, essential for the indirect determination of iodate. The application of the standard addition method enabled detection limits of 0.14 µM for iodide and 0.02 µM for iodate, together with the direct introduction of the target water samples, coastal and inland bathing waters. The results obtained were in agreement with those obtained by ICP-MS and a colorimetric reference procedure. Recovery tests also confirmed the accuracy of the developed method which was effectively applied to bathing waters and seaweed extracts. PMID:25435219

  18. RP- HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF MONTELUKAST SODIUMAND DESLORATIDINE FROM BULK AND TABLETS FORMULATION

    Directory of Open Access Journals (Sweden)

    Kalyankar Tukaram M

    2012-07-01

    Full Text Available A simple, rapid, accurate, precise and validated High performance Liquid Chromatographic method for the simultaneous estimation of Desloratidine(DES and Montelukast sodium(MON in bulk and Multicomponant formulation. The Reversed-phase liquid chromatographic analysis was performed on a Hypersil C18 column (250mm, 4.6mm i.d., 5 μm particle size column with mobile phase Acetonitrile: 0.05M Potassium Dihydrogen ortho-phosphates with 1.5ml Triethylamine of pH 3 (65: 35 v/v and column temperature at 40°C. The flow rate of the mobile phase was adjusted to 1.3 mL/min and the injection volume was 10 μl. Detection was performed at 210 nm. The retention time for DES and MON were 2.12 min and 12.76 min respectively. The method was validated and shown to be linear for DES and MON in 10-60 µg/mL (r2=0.998 and 20-120 µg/mL (r2=0.998 respectively. The relative standard deviation of DES and MON for intra-day was 0.2746 and 0.7637 respectively, inter-day was found to be, 0.7836 and 0.9317 respectively. The developed RP- HPLC method is suitable for estimation of Montelukast sodium and Desloratidine in tablet formulation. Hence this method can be used in quality control for routine analysis of the finish drug product.

  19. Validated spectrophotometric methods for the estimation of moxifloxacin in bulk and pharmaceutical formulations

    Science.gov (United States)

    Motwani, Sanjay K.; Chopra, Shruti; Ahmad, Farhan J.; Khar, Roop K.

    2007-10-01

    New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods were developed and validated for the estimation of moxifloxacin in bulk and pharmaceutical formulations. Moxifloxacin was estimated at 296 nm in 0.1N hydrochloric acid (pH 1.2) and at 289 nm in phosphate buffer (pH 7.4). Beer's law was obeyed in the concentration range of 1-12 μg ml -1 ( r2 = 0.9999) in hydrochloric acid and 1-14 μg ml -1 ( r2 = 0.9998) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.63 × 10 4 l mol -1 cm -1 and 9.5 ng cm -2/0.001 A in hydrochloric acid; and 4.08 × 10 4 l mol -1 cm -1 and 10.8 ng cm -2/0.001 A in phosphate buffer media, respectively indicating the high sensitivity of the proposed methods. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.0402, 0.1217 μg ml -1 in hydrochloric acid and 0.0384, 0.1163 μg ml -1 in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of moxifloxacin in pharmaceutical formulations (tablets, i.v. infusions, eye drops and polymeric nanoparticles). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation moxifloxacin in different dosage forms and dissolution studies.

  20. STABILIZATION OF DEWATERED SEWAGE SLUDGE BY AEROBIC COMPOSTING METHOD: USING SAWDUST AS BULKING AGENTS

    Directory of Open Access Journals (Sweden)

    A PARVARESH

    2002-12-01

    Full Text Available Introduction. Sludge production from municipal wastewater treatment plants should have quality standards before disposal in to the environment. Environmental specialists classified sewage sludge as a hazardous waste because of high organic compounds and pathogenic microorganisms. They belive that sewage should be stabilized before disposal and so composting of sewage sludge is an effective and economical method to stabilize. Sewage sludge compost could be used to improve soil structure and enrich the soil with nutrients. Methods. To evaluate the optimum conditions of aerobic compost, the mixture of dewatered sewage sludge from Isfahan municipal waste water treatment plant and sawdust as bulking agent were used. Pilot scale study were performed in Isfahan municipal waste water treatment plant. To perform this research project, the dewatered sewage sludge with humidity between 78 to 82 percent were mixed with sawdust. Turning over method of the piles with one week interval were applied to aerate the mixture. Temperature of the piles were monitored at different depths daily. Other parameters such as N, G, organic matters and pH were determined weekly. Total and fecal coli form, and salmonella were determined at the beginning and end of the composting process, also heavy metals were measured at the same time. Results. The results of this study showed that after days, temperature of the mixture reached up to 55 G, and were stabled for 15 days. Humidity, organic matter, organic carbon and GIN ratio of the mixture decreased over the period of the study, due to increasing the temperature. Also organic matter and humidity mainly decreased in thermofilic phase. The number of total and fecal coliform and also salmonella decreased to A class standards of US.EPA at the end of the operation. Discussion. The results of the study also showed that, this type of composting method is reliable, and simple to schedule, with high flexibility and low odor

  1. SPECTROPHOTOMETRIC METHOD DEVELOPMENT OF RAMIPRIL AND HYDROCHLOROTHIAZIDE IN BULK AND MARKETED FORMULATION BY VIERORDT’S METHOD

    Directory of Open Access Journals (Sweden)

    Ananda Thangadurai

    2012-06-01

    Full Text Available This paper describes a simple, accurate, specific and validated method for quantitative determination of Ramipril and Hydrochlorothiazide in bulk and marketed dosage formulation by Vierordt’s method. This method a involves simultaneous equation at 219.52 nm (λ max of Ramipril and 270.54 nm (λ max of Hydrochlorothiazide.A study was carried out all the parameters established as per ICH, i.e. accuracy, precision, linearity, LOD, LOQ. Method was found to be linear in the range of 10-80µg/ml and 1.7-6.7µg/ml for Ramipril and Hydrochlorothiazide respectively with a correlation co-efficient 0.9945 for Ramipril, and 0.9976 for Hydrochlorothiazide. The percentage recovery is 94% for Ramipril, 102% Hydrochlorothiazide which reflect that the method is free from the interference of impurities and other additives during estimation of drug in formulation. The results of analysis have been validated by the recovery studies and were found satisfactory.

  2. Fabrication of Nb3Al superconducting bulks by mechanical alloying method

    Science.gov (United States)

    Qi, Ming; Pan, Xi Feng; Zhang, Ping Xiang; Cui, Li Jun; Li, Cheng Shan; Yan, Guo; Chen, Yong Liang; Zhao, Yong

    2014-06-01

    Since it can directly prepare the Nb-Al supersaturated solid solution, mechanical alloying is thought as a promising method to make high-performance Nb3Al superconductors at a low temperature annealing condition, without the complicated rapid heating, quenching and transformation (RHQT) process. In this paper, we investigate the effects of milling time, the content of Al and annealing temperature on phase formation and superconducting properties of mechanical alloying Nb3Al bulks in detail. The study results show that Nb-Al supersaturated solid solution could be obtained by high energy ball milling, as long as the Nb-Al blended powder is ball milled for 1 h, even the amorphous phase appears with the ball milling time prolonging to 10 h, the Nb-Al intermetalics do not come out either. Amorphous phase is hardly beneficial to synthesizing the Nb3Al phase, instead, it will make the products impurity. By optimizing the milling time, elements composition and annealing temperature , pure Nb3Al phase is obtained and the highest onset superconducting transition temperature (Tc-onset) reaches 15.8 K and the critical current density (Jc) 106 A/cm2 at 8 K without outer field. This paper also discusses the main reasons that affect the superconducting properties of mechanical alloying Nb3Al superconductor.

  3. Heat transfer to and from vegetated surfaces - An analytical method for the bulk exchange coefficients

    Science.gov (United States)

    Massman, William J.

    1987-01-01

    The semianalytical model outlined in a previous study (Massman, 1987) to describe momentum exchange between the atmosphere and vegetated surfaces is extended to include the exchange of heat. The methods employed are based on one-dimensional turbulent diffusivities, and use analytical solutions to the steady-state diffusion equation. The model is used to assess the influence that the canopy foliage structure and density, the wind profile structure within the canopy, and the shelter factor can have upon the inverse surface Stanton number (kB exp -1), as well as to explore the consequences of introducing a scalar displacement height which can be different from the momentum displacement height. In general, the triangular foliage area density function gives results which agree more closely with observations than that for constant foliage area density. The intended application of this work is for parameterizing the bulk aerodynamic resistances for heat and momentum exchange for use within large-scale models of plant-atmosphere exchanges.

  4. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE......) method separates dissolved Cd into free divalent Cd (Cd 2+) and complexed Cd and furthermore separates the latter into the operationally defined forms: labile, slowly labile and stable complexes. The dialysis (ED) method determines high molecular weight Cd complexes (above 1000mol. wt). For both methods...... the reproducibility was good. By combining the results of the GEOCHEM calculations in terms of the inorganic complexes, and the IE results, the fractions of free and inorganically complexed Cd were estimated. The IE and ED results furthermore provided information about the organic complexes. Selected...

  5. Quantitative 1H-NMR Method for the Determination of Tadalafil in Bulk Drugs and its Tablets

    Directory of Open Access Journals (Sweden)

    Qingyun Yang

    2015-07-01

    Full Text Available A simple, rapid, accurate, and selective quantitative nuclear magnetic resonance method for the determination of tadalafil in bulk drugs and its tablets was established and evaluated. Spectra were obtained in dimethylsulfoxide-d6 using 2,4-dinitrotoluene as the internal standard. In this study, the method’s linearity, range, limit of quantification, stability, precision, and accuracy were validated. The results were consistent with those obtained from high-performance liquid chromatography analysis. Thus, the proposed method is a useful and practical tool for the determination of tadalafil in bulk drugs and its tablets.

  6. On the bulk β-Ga2O3 single crystals grown by the Czochralski method

    Science.gov (United States)

    Galazka, Zbigniew; Irmscher, Klaus; Uecker, Reinhard; Bertram, Rainer; Pietsch, Mike; Kwasniewski, Albert; Naumann, Martin; Schulz, Tobias; Schewski, Robert; Klimm, Detlef; Bickermann, Matthias

    2014-10-01

    The growth of bulkx β-Ga2O3 single crystals by the Czochralski method is reported and discussed in terms of crucial growth conditions and correlated with basic electrical and optical properties of the obtained crystals. β-Ga2O3 crystals have a tendency to a spiral formation due to free carrier absorption in the near infrared (NIR) wavelength range, which hampers radiative heat transfer through the growing crystal. Moderate or low free electron concentrations (crystals with a high crystallized fraction (g≥0.5). The use of a CO2-containing growth atmosphere provides oxygen partial pressures between 0.8 and 4.4×10-2 bar that is sufficient to obtain cylindrical and semiconducting crystals. Doping with Sn increases the free electron concentration in the crystals to high values (~1019 cm-3) that lead to an immediate spiral formation, while doping with Mg (>6 wt ppm) provides insulating crystals with reduced probability of the spiral formation. The estimated Mg equilibrium segregation coefficient across the liquid-solid interface is 0.10-0.12. Annealing of undoped crystals in an oxidizing atmosphere at temperatures ≥1200 °C for 20 h decreases the bulk free electron concentration by about one order of magnitude, while the crystal surface becomes insulating. However, Mg:β-Ga2O3 crystals are insensitive to annealing in both oxygen- and hydrogen-containing atmospheres. The transmittance spectra showed a steep absorption edge at 260 nm and virtually full transparency in the visible and NIR wavelength range for low and moderate free electron concentrations. We also demonstrated the possibility of growing 2 in. diameter β-Ga2O3 single crystals by the Czochralski method. The good crystal quality is evidenced by rocking curve FWHM values of below 50". We noted that most dislocations propagate parallel to (100) plane. Further, we also provide thermal properties of the crystals as a function of temperature.

  7. DEVELOPMENT AND VALIDATION OF UV SPECTROPHOTOMETRIC ESTIMATION OF EBASTINE IN BULK AND TABLET DOSAGE FORM USING AREA UNDER CURVE METHOD

    Directory of Open Access Journals (Sweden)

    Dahivadkar Manish Sudhakar

    2013-06-01

    Full Text Available The aim of this work is to develop a simple, accurate, reproducible and cost effective spectrophotometric method for determination of Ebastine in bulk and pharmaceutical dosage form. This method is basedon area under curve (AUC in wavelength range of 247-257nm and method has followed linearity in the concentration range of 5-30μg/ml. Methanol was used as a solvent. The developed analytical method was validated as per International Conference on Harmonization (ICH guidelines. The value of correlation coefficient (R2 was 0.999. Limit of Detection and Limit of Quantitation were calculated as 0.78µg/ml and 2.37µg/ml, respectively. Results of the recovery studies showed good accuracy of the method. Validation results suggest that the developed method can be used for routine quality control studies for assay of Ebastine in bulk and tablet dosage form.

  8. DEVELOPMENT AND VALIDATION OF A UV SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF LISINOPRIL BOTH IN BULK AND MARKETED DOSAGE FORMULATIONS

    OpenAIRE

    Vijayalaxmi Chavan; Poonam Phasate

    2015-01-01

    Lisinopril is angiotensin converting enzyme inhibitor widely used in management of blood pressure and congestive heart failure. This study proposes a simple, rapid and economic method of analysis of lisinopril in bulk as well as in formulation using UV spectrophotometer. The present method has been developed in distil water which makes it economic and reproducible. Absorption maxima was obtained at 206nm. The method is validated using ICH Q2R1 guideline for various parameters like precision, ...

  9. Miniaturized preconcentration methods based on liquid-liquid extraction and their application in inorganic ultratrace analysis and speciation: A review

    International Nuclear Information System (INIS)

    Liquid-liquid extraction (LLE) is widely used as a pre-treatment technique for separation and preconcentration of both organic and inorganic analytes from aqueous samples. Nevertheless, it has several drawbacks, such as emulsion formation or the use of large volumes of solvents, which makes LLE expensive and labour intensive. Therefore, miniaturization of conventional liquid-liquid extraction is needed. The search for alternatives to the conventional LLE using negligible volumes of extractant and the minimum number of steps has driven the development of three new miniaturized methodologies, i.e. single-drop microextraction (SDME), hollow fibre liquid-phase microextraction (HF-LPME) and dispersive liquid-liquid microextraction (DLLME). The aim of this paper is to provide an overview of these novel preconcentration approaches and their potential use in analytical labs involved in inorganic (ultra)trace analysis and speciation. Relevant applications to the determination of metal ions, metalloids, organometals and non-metals are included

  10. Simplified derivatization method for the speciation analysis of organolead compounds in water and peat samples using in-situ butylation with tetrabutylammonium tetrabutylborate and GC-MIP AES

    Energy Technology Data Exchange (ETDEWEB)

    Heisterkamp, M.; Adams, F.C. [University of Antwerp (UIA), Wilrijk (Belgium). Micro and Trace Analysis Centre

    1998-11-01

    A simplified derivatization method for the speciation analysis of organolead compounds in environmental samples followed by gas chromatography-microwave induced plasma atomic emission detection is developed. An in-situ butylation using tetrabutylammonium tetrabutylborate in an acetate buffer medium of pH 4.0 with simultaneous extraction of the derivatized organolead species into hexane was performed; for the analysis of the peat samples, the desorption of the different species from the matrix by acid leaching was also included. Detection limits at the sub-ng L{sup -1} range, comparable to those achieved by Grignard-alkylation, were obtained for the different species. The accuracy of the method was confirmed by analysis of a standard reference material (BCR-CRM 605, road dust). Examples of applications for the analysis of tap water and peat are given. (orig.) With 4 figs., 4 tabs., 30 refs.

  11. Development of a novel, fast, sensitive method for chromium speciation in wastewater based on an organic polymer as solid phase extraction material combined with HPLC-ICP-MS.

    Science.gov (United States)

    Jia, Xiaoyu; Gong, Dirong; Xu, Bin; Chi, Qiaoqiao; Zhang, Xian

    2016-01-15

    Speciation analysis of inorganic chromium in wastewater is of great significance for the monitoring of environmental pollution. In this work, N,N-bis(2-aminoethyl)ethane-1,2-diamine functionalized poly(chloromethyl styrene-co-styrene) was synthesized, characterized and used as the adsorbent to preconcentrate chromium species in environmental waters by on line solid-phase extraction (SPE). The trace speciation analysis of Cr(III) and Cr(VI) in wastewater has been used by short-column high-performance liquid chromatography hyphenated to inductively coupled plasma spectrometry (HPLC-ICP-MS) after on-line SPE. Cr(III) and Cr(VI) have been adsorbed on the anion exchange column after transforming the cationic Cr(III) to an anionic [Cr(III)-EDTA](-) complex devoid of re-dox reagent, and then eluted rapidly (within seconds) with a very low concentration of tetrabutylammonium hydroxide (TBAH) solution. This method provides a reliable on-line preconcentration method and detection coupled technique. Under the optimized conditions, high enrichment factors have been obtained for Cr(VI) and [Cr(III)-EDTA](-) with 30mL sample solution up to 105 and 128, respectively. The low detection limits of 0.0068ng mL(-1) and 0.0041ng mL(-1), with the relative standard deviations (RSDs) of 4.3% and 3.6% were obtained for Cr(VI) and [Cr(III)-EDTA](-), respectively. The developed method was validated by analyzing Certified Reference Materials GSBZ50027-94, and the spike tests were also performed. At the same time, thanks to the merit of simple operation, rapid adsorption/desorption dynamics, high enrichment and low LODs, the established method was applied to analyze three wastewater samples from different discharge port. PMID:26592590

  12. New down-hole TDR method for deep profile soil water content and bulk electrical conductivity

    Science.gov (United States)

    Comprehensive irrigation and salinity management both require accurate knowledge of field soil water content and bulk electrical conductivity to depths greater than the root zone depth in agricultural fields. Scientists at the USDA-ARS Conservation & Production Research Laboratory, Bushland, Texas, ...

  13. New method for introducing nanometer flux pinning centers into single domain YBCO bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W.M., E-mail: yangwm@snnu.edu.cn; Wang, Miao

    2013-10-15

    Highlights: • Single domain YBCO bulks with Bi{sub 2}O{sub 3} additions fabricated by TSIG process. • Nanoscale Y{sub 2}Ba{sub 4}CuBiOx(YBi2411) particles introduced by Bi{sub 2}O{sub 3} additions. • The YBi2411 particles are about 150 nm, can act as effective flux pinning centers. • The optimal addition of Bi{sub 2}O{sub 3} is 0.7wt% to achieve higher levitation force. • The result is helpful to improve the quality of REBCO bulk superconductors. -- Abstract: Single domain YBCO superconductors with different additions of Bi{sub 2}O{sub 3} have been fabricated by top seeded infiltration and growth process (TSIG). The effect of Bi{sub 2}O{sub 3} additions on the growth morphology, microstructure and levitation force of the YBCO bulk superconductor has been investigated. The results indicate that single domain YBCO superconductors can be fabricated with the additions of Bi{sub 2}O{sub 3} less than 2 wt%; Bi{sub 2}O{sub 3} can be reacted with Y{sub 2}BaCuO{sub 5} and liquid phase and finally form Y{sub 2}Ba{sub 4}CuBiO{sub x}(YBi2411) nanoscale particles; the size of the YBi2411 particles is about 100 nm, which can act as effective flux pinning centers. It is also found that the levitation force of single domain YBCO bulks is increasing from 13 N to 34 N and decreasing to 11 N with the increasing of Bi{sub 2}O{sub 3} addition from 0.1 wt% to 0.7 wt% and 2 wt%. This result is helpful for us to improve the physical properties of REBCO bulk superconductors.

  14. Speciation of radionuclides in the environment

    International Nuclear Information System (INIS)

    Methods for the determination of the speciation of radionuclides in aerosols, in aquatic solutions, in sediments, soils and rocks are reviewed. At present, most of the results about speciation are deduced from model calculations, model experiments, and separation of species (forms) of radionuclides, e.g., by sequential extraction procedures. Methods of direct determination of speciation of radionuclides (e.g. by laser induced spectroscopy) are in general not yet sensitive enough for a measurement of the very low concentrations of radionuclides in the environment. The methodological part of this paper is followed by a review of the very abundant literature about speciation of important radionuclides in the environment, i.e. in the atmosphere, hydrosphere and lithosphere. The review does not include the biosphere. Literature up to spring 1993 is included (with a few more recent additions). (author)

  15. Bulk undercooling

    Science.gov (United States)

    Kattamis, T. Z.

    1984-01-01

    Bulk undercooling methods and procedures will first be reviewed. Measurement of various parameters which are necessary to understand the solidification mechanism during and after recalescence will be discussed. During recalescence of levitated, glass-encased large droplets (5 to 8 mm diam) high speed temperature sensing devices coupled with a rapid response oscilloscope are now being used at MIT to measure local thermal behavior in hypoeutectic and eutectic binary Ni-Sn alloys. Dendrite tip velocities were measured by various investigators using thermal sensors or high speed cinematography. The confirmation of the validity of solidification models of bulk-undercooled melts is made difficult by the fineness of the final microstructure, the ultra-rapid evolution of the solidifying system which makes measurements very awkward, and the continuous modification of the microstructure which formed during recalescence because of precipitation, remelting and rapid coarsening.

  16. Potential of advance NDT method for water measurement in a bulk paper-recycling

    International Nuclear Information System (INIS)

    Paper recycling industries usually buy their raw material from suppliers. Bulk used paper supplied to recycling industry may contain water in their internal voids. This is because the price of the used paper is currently based on their weight and has a huge potential of suppliers to add water to increase the price. The aims of our experiment are to establish the neutron calibration curve and to develop a correction factor of weight measurement during purchasing. This study presents an advance non-destructive testing technique for rapid and in-situ measurement of water content in a bulk used paper. A fast neutron source (Am-Be 241) and a portable backscattering neutron detector were used for water measurement. The experiments were conducted by measuring a series of wet paper added with certain amount of water. As a result, a neutron calibration curve for water measurement in bulk used paper was established. A total of six bands for weight correction based on the calibration curve have been proposed. (author)

  17. The effect of hygroscopicity on sea-spray aerosol fluxes: a comparison of high-rate and bulk correction methods

    Directory of Open Access Journals (Sweden)

    D. A. J. Sproson

    2012-09-01

    Full Text Available The eddy covariance technique is the most direct of the methods that have been used to measure the flux of sea-spray aerosol between the ocean and atmosphere, but has been applied in only a handful of studies. However, unless the aerosol is dried before the eddy covariance measurements are made, the hygroscopic nature of sea-spray may combine with a relative humidity flux to result in a bias in the calculated aerosol flux. "Bulk" methods have been presented to account for this bias, however they rely on assumptions of the shape of the aerosol spectra which may not be valid for near-surface measurements of sea-spray.

    Here we describe a method of correcting aerosol spectra for relative humidity induced size variations at the high frequency (10 Hz measurement timescale, where counting statistics are poor and the spectral shape cannot be well represented by a simple power law. Such a correction allows the effects of hygroscopicity and relative humidity flux on the aerosol flux to be explicitly evaluated and compared to the bulk corrections, both in their original form and once reformulated to better represent the measured mean aerosol spectra. In general, the bulk corrections – particularly when reformulated for the measured mean aerosol spectra – perform relatively well, producing flux corrections of the right sign and approximate magnitude. However, there are times when the bulk methods either significantly over- or underestimate the required flux correction. We thus conclude that, where possible, relative humidity corrections should be made at the measurement frequency.

  18. Bulk Analysis Method of Gold Determination in Ores Using Epithermal Neutrons of Electron Accelerator Microtron MT-22

    CERN Document Server

    Gerbish, Sh; Baatarkhuu, D; Ganbold, G; Belov, A G

    2004-01-01

    Bulk analysis method of gold determination in ores by Instrumental Neutron Activation Analysis (INAA) is described. The powder (100-200 mesh) samples were irradiated in Cd foils of 1 mm thick with photo-neutrons at the Microtron MT-22 of the Nuclear Research Center, Mongolian State University (Ulaanbaatar). The sensitivity of 0.1 mg/kg Au can be obtained using 30-50 g samples and irradiation time of 1-2 h.

  19. Bulk analysis method of gold determination in ores using epithermal neutrons of electron accelerator microtron MT-22

    International Nuclear Information System (INIS)

    Bulk analysis method of gold determination in ores by Instrumental Neutron Activation Analysis (INAA) is described. The powder (100-200 mesh) samples were irradiated in Cd foils of 1 mm thick with photo-neutrons at the Microtron MT-22 of the Nuclear Research Center, Mongolian State University (Ulaanbaatar). The sensitivity of 0.1 mg/kg Au can be obtained using 30-50 g samples and irradiation time of 1-2 h

  20. Novel LC Method Development and Validation for Simultaneous Determination of Montelukast and Doxofylline in Bulk and Pharmaceutical Dosage Forms

    OpenAIRE

    Gadapa Nirupa; A Siva Kumar; Upendra M. Tripathi

    2013-01-01

    A novel rapid HPLC method was developed for simultaneous determination of montelukast and doxofylline in bulk and pharmaceutical dosage forms. Development of an analytical method for simultaneous estimation of drugs requires a lot of efforts and of course it is a challenging task. The method was developed by using C18 (150 mm×4.6 mm, 5 μm) column; mobile phase consisting of methanol and phosphate buffer at pH 4.5; the flow rate of 1.0 mL/min and ultraviolet detection at 280 nm. Both drugs wer...

  1. Simultaneous Estimation of Ibuprofen and Phenylephrine Hydrochloride in Bulk and Combined Dosage Form by First Derivative UV Spectrophotometry Method

    OpenAIRE

    Mehul Patel; Bhavna Patel; Shraddha Parmar

    2013-01-01

    A simple, precise, rapid, and economic method was developed for the simultaneous determination of Ibuprofen and Phenylephrine HCl in bulk and combined dosage form. This method involves first-order derivative spectroscopy using 248 nm and 237 nm as zero crossing points for Ibuprofen and Phenylephrine HCl, respectively. For spectrophotometric method 0.1 N NaOH was used as a solvent. The linearity was established over the concentration range of 12–72 μg/mL and 1.5–22 μg/mL for Ibuprofen and Phen...

  2. NEW ANALYTICAL METHODS AND THEIR VALIDATION FOR THE ESTIMATION OF METOPROLOL SUCCINATE IN BULK AND MARKETED FORMULATION

    Directory of Open Access Journals (Sweden)

    Viral Bechara

    2015-02-01

    Full Text Available Metoprolol succinate is cardiovascular agent. Mainly used for the treatment of hypertension, heart failure, and cardiovascular diseases. Purpose: Analytical methods are required to characterize drug substances and drug products composition during all phases of pharmaceutical development. Development of methods to achieve the final goal of ensuring the quality of drug substances and drug products must be implemented in conjunction with an understanding of the chemical behavior and physicochemical properties of the drug substance. This determination requires highly sophisticated instruments and methods like HPLC, HPTLC and Spectrophotometer. Hence there was a need for the development of newer, simple, sensitive, rapid, accurate and reproducible analytical methods for the routine estimation of metoprolol succinate in bulk and pharmaceutical dosage form. Methods: The present work describes two new spectrophotometric methods for the determination of metoprolol succinate in bulk and marketed formulations. Method A is based on oxidation reaction. Metoprolol succinate in presence of acidic medium reacts with excess amount of chloramine-T and remaining chloramine-T react with malachite green to produce orange colour chromogen which showed λmax at 516 nm. In Method B, the drug was diazotised with sodium nitrite in presence of hydrochloric acid and then it was coupled with β-naphthol in alkaline medium. Which produce red colour chromogen which showed λmax at 688 nm. Results: The linearity was found in concentration range of 5-30μg/ml for both method A and method B. The correlation coefficient was found to be 0.9983 and 0.9993 for method A and method B respectively. The methods were validated as per ICH guidelines. The LOD and LOQ for estimation of Metoprolol succinate were found as 0.0773, 0.2343 for method A and 0.0667, 0.2021 for method B respectively. Conclusion: Proposed methods were successfully applied for the quantitative estimation of

  3. Speciation of Long-Lived Radionuclides in the Environment

    DEFF Research Database (Denmark)

    Hou, Xiaolin

    , isotopes of Pu, and 237Np in seawater, fresh water, soil, sediment, vegetations, and concrete. The developed methods are used for the investigation of the chemical speciation of these radionuclides as well as their environmental behaviours, especially in Danish environment. In addition the speciation of Pu......This project started in November 2005 and ended in November 2008, the work and research approaches are summarized in this report. This project studied the speciation of radionuclides in environment. A number of speciation analytical methods are developed for determination of species of 129I, 99Tc...

  4. Electrodynamic balance measurements of thermodynamic, kinetic, and optical aerosol properties inaccessible to bulk methods

    Directory of Open Access Journals (Sweden)

    S. S. Steimer

    2015-06-01

    Full Text Available Measurements of a single, levitated particle in an electrodynamic balance are an established tool for deriving thermodynamic and material data such as density, refractive index and activities of components of an aqueous solution under supersaturated conditions, where bulk measurements are not possible. The retrieval relies on combining mass-to-charge data and size data from light scattering. Here, we use a combination of low- and high-resolution Mie resonance spectroscopy to obtain radius data, enabling an accurate size determination not only when the particle is in equilibrium, but also when it is out of equilibrium due to kinetic limitation of mass transport. With the data measured under non-equilibrium conditions, it is possible to retrieve the water diffusivity. A challenge is that the radius retrieval by comparing measured light scattering with Mie theory requires the knowledge of refractive index as a function of concentration. Here, we show an iterative retrieval of refractive index and size for compounds for which data cannot be obtained in the bulk either due to lack of sufficient amounts of sample or limited solubility. We demonstrate the measurement strategy and the retrieval of water activity, density, refractive index and water diffusivity for aqueous shikimic acid. Water diffusivity in concentrated shikimic acid decreases by 6 orders of magnitude at 250 K compared to that at room temperature.

  5. Electrodynamic balance measurements of thermodynamic, kinetic, and optical aerosol properties inaccessible to bulk methods

    Directory of Open Access Journals (Sweden)

    S. S. Steimer

    2015-01-01

    Full Text Available Measurements of a single, levitated particle in an electrodynamic balance are an established tool for deriving thermodynamic and material data such as density, refractive index and activities of components of an aqueous solution under supersaturated conditions, where bulk measurements are not possible. The retrieval relies on combining mass-to-charge data and size data from light scattering. Here, we use a combination of low- and high-resolution Mie resonance spectroscopy to obtain radius data, enabling an accurate size determination not only when the particle is in equilibrium, but also when it is out of equilibrium due to kinetic limitation of mass transport. With the data measured under non-equilibrium conditions, it is possible to retrieve the water diffusivity. A challenge is that the radius retrieval by comparing measured light scattering with Mie theory requires the knowledge of refractive index as a function of concentration. Here, we show an iterative retrieval of refractive index and size for compounds for which data cannot be obtained in the bulk either due to lack of sufficient amounts of sample or limited solubility. We demonstrate the measurement strategy and the retrieval of water activity, density, refractive index and water diffusivity for aqueous shikimic acid. Water diffusivity in concentrated shikimic acid decreases by 6 orders of magnitude at 250 K compared to that at room temperature.

  6. A coupling of rapid crystallization and plastic consolidation as a method for mass scale production of bulk submicrocrystalline aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dybiec, Henryk [Department of Structure and Mechanics of Solids US and T AGH, al. Mickiewicza 30, 30 059 Krakow (Poland)

    2010-05-15

    Rapid crystallization is a well-known method for production of ultrafine-grained metallic materials using the overcooling effect. Unfortunately, this method provides material in dispersed form with very limited dimensions of individual particles, which must be consolidated to bulk form for engineering use. To prevent destabilization of ultrafine-grain structure of polycrystalline particles the consolidation process should to be quick enough and must be conducted at reasonably low temperatures. Such reasons suggest the process of plastic consolidation. In this process plastic deformation of individual particles develops new surfaces in status nascendi, which is able to create strong bonds between collectively deformed particles of dispersed materials and converts the powder to the bulk form. The plastic consolidation by isothermal extrusion is the agglomeration process of plastically deformable particles without involving diffusion effects. Bulk materials with no measurable porosity are the product of this process, in which the character of interaction among individual particles of powder shows similar character to interaction at grain boundaries in polycrystalline metals. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  7. Fast methods of computing bulk radiative properties of inhomogeneous clouds illuminated by solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, P. [Colorado State Univ., Fort Collins, CO (United States)

    1995-09-01

    The use of cloud fraction as a means of incorporating horizontal cloud inhomogeneity in radiative transfer calculations is widespread in the atmospheric science community. This research attempts to bypass the use of cloud fraction in radiative transfer modeling for two-dimensional media. Gabriel describes two approximation techniques useful in calculating the domain averaged bulk radiative properties such as albedo, flux divergence and mean radiance that dispense with the need to use cloud fraction as a specifier of cloud inhomogeneity. The results suggest that the variability of the medium can largely be accounted for through the pseudo-source term, offering hope of parameterizing the equation of transfer in terms of the statistical properties of the medium. 1 fig.

  8. STABILITY INDICATING RP-LC METHOD FOR DETERMINATION OF RASAGILINE MESYLATE IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    OpenAIRE

    R. Narendra Kumar; G. Nageswara Rao; P.Y. Naidu

    2010-01-01

    An isocratic stability indicating liquid chromatographic method has been developed and validated for the determination of Rasagiline in bulk drug and its pharmaceutical dosage forms. Separation of the drug with degradation products was achieved using Puroshere Star, C18, 150 x 4.6mm; 5μm column as stationary phase and pH 7.0(±0.05) buffer: Acetonitrile (40:60,v/v) as mobile phase at a flow rate of 1.0 mL/min. UV detection was performed at 210 nm. The method is linear over the range of 4.8 – 1...

  9. Development and validation of an RP-HPLC method for quantitative estimation of eslicarbazepine acetate in bulk drug and tablets

    OpenAIRE

    M Singh; Kumar, L.; Arora, P.; Mathur, S. C.; Saini, P. K.; Singh, R. M.; G. N. Singh

    2013-01-01

    A convenient, simple, accurate, precise and reproducible RP-HPLC method was developed and validated for the estimation of eslicarbazepine acetate in bulk drug and tablet dosage form. Objective was achieved under optimised chromatographic conditions on Dionex RP-HPLC system with Dionex C18 column (250×4.6 mm, 5 μm particle size) using mobile phase composed of methanol and ammonium acetate (0.005 M) in the ratio of 70:30 v/v. The separation was achieved using an isocratic elution method with a ...

  10. Development and validation of HPTLC method for simultaneous determination of amlodipine besylate and metoprolol succinate in bulk and tablets

    OpenAIRE

    P. S. Jain; Patel, M.K. (Martin); S B Bari; S. J. Surana

    2012-01-01

    A simple, selective, precise high-performance thin-layer chromatographic method for simultaneous determination of amlodipine besylate and metoprolol succinate in bulk and pharmaceutical combined dosage form was developed and validated. The method employed HPTLC aluminum plates precoated with silica gel 60F-254 (10×10) as the stationary phase. The solvent system consisted of toluene:ethyl acetate:methanol:triethylamine (4:1:1:0.4 v/v/v). The system was found to give a compact spot for amlodipi...

  11. A method to estimate the composition of the bulk silicate Earth in the presence of a hidden geochemical reservoir

    Science.gov (United States)

    Korenaga, Jun

    2009-11-01

    The possibility of a hidden geochemical reservoir in the deep mantle has long been debated in geophysics and geochemistry, because of its bearings on the structure of the core-mantle boundary region, the origin of hotspots, the style of mantle convection, the history of the geomagnetic field, and the thermal evolution of Earth. The presence of such hidden reservoir, however, may invalidate existing models for the composition of the bulk silicate Earth because these models invariably assume that major chemical differentiation in the mantle follows the compositional trend exhibited by upper-mantle rocks. This article presents a new method to estimate the composition of the bulk silicate Earth by explicitly taking into account the possibility of a hidden reservoir. This geochemical inference is formulated as a nonlinear inverse problem, for which an efficient Markov chain Monte Carlo algorithm is developed. Inversion results indicate that the formation of a hidden reservoir, if any, took place at low pressures probably within the first 10 Myr of the history of the solar system and was subsequently lost from the Earth by impact erosion. The global mass balance of the bulk silicate Earth is revisited with the inversion results, and the depletion of highly incompatible elements in the present-day Earth is suggested to be moderate.

  12. A method to search for bulk motions in the ICM with {\\sl Chandra} CCD spectra: application to the Bullet cluster

    CERN Document Server

    Liu, Ang; Tozzi, Paolo; Zhu, Zong-Hong

    2015-01-01

    We propose a strategy to search for bulk motions in the intracluster medium (ICM) of merging clusters based on {\\sl Chandra} CCD data. Our goal is to derive robust measurements of the average redshift of projected ICM regions obtained from the centroid of the $K_\\alpha$ line emission. We thoroughly explore the effect of the unknown temperature structure along the line of sight to accurately evaluate the systematic uncertainties on the ICM redshift. We apply our method to the "Bullet cluster" (1E~0657-56). We directly identify 23 independent regions on the basis of the surface brightness contours, and measure the redshift of the ICM averaged along the line of sight in each. We find that the redshift distribution across these regions is marginally inconsistent with the null hypothesis of a constant redshift or no bulk motion in the ICM, at a confidence level of about $2\\, \\sigma$. We tentatively identify the regions most likely affected by bulk motions and find a maximum velocity gradient of about $(46\\pm 13)$ ...

  13. Uranium speciation in plants

    International Nuclear Information System (INIS)

    Detailed knowledge of the nature of uranium complexes formed after the uptake by plants is an essential prerequisite to describe the migration behavior of uranium in the environment. This study focuses on the determination of uranium speciation after uptake of uranium by lupine plants. For the first time, time-resolved laser-induced fluorescence spectroscopy and X-ray absorption spectroscopy were used to determine the chemical speciation of uranium in plants. Differences were detected between the uranium speciation in the initial solution (hydroponic solution and pore water of soil) and inside the lupine plants. The oxidation state of uranium did not change and remained hexavalent after it was taken up by the lupine plants. The chemical speciation of uranium was identical in the roots, shoot axis, and leaves and was independent of the uranium speciation in the uptake solution. The results indicate that the uranium is predominantly bound as uranyl(VI) phosphate to the phosphoryl groups. Dandelions and lamb's lettuce showed uranium speciation identical to lupine plants. (orig.)

  14. Change of variables as a method to study general β-models: Bulk universality

    International Nuclear Information System (INIS)

    We consider β matrix models with real analytic potentials. Assuming that the corresponding equilibrium density ρ has a one-interval support (without loss of generality σ = [−2, 2]), we study the transformation of the correlation functions after the change of variables λi → ζ(λi) with ζ(λ) chosen from the equation ζ′(λ)ρ(ζ(λ)) = ρsc(λ), where ρsc(λ) is the standard semicircle density. This gives us the “deformed” β-model which has an additional “interaction” term. Standard transformation with the Gaussian integral allows us to show that the “deformed” β-model may be reduced to the standard Gaussian β-model with a small perturbation n−1h(λ). This reduces most of the problems of local and global regimes for β-models to the corresponding problems for the Gaussian β-model with a small perturbation. In the present paper, we prove the bulk universality of local eigenvalue statistics for both one-cut and multi-cut cases

  15. Bulk single crystal growth of SiGe by PMCZ method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Weilian; NIU Xinhuan; CHEN Hongjian; ZHANG Jianxin; SUN Junsheng; ZHANG Enhuai

    2003-01-01

    A new type of magnetic device was used to replace the conventional electro-magnetic field for CZSi (doped with Ge) growth. The device was composed of three permanent magnetic rings and called PMCZ device. The lines of magnetic force are horizontally distributed at radial 360°. Using the ring permanent magnetic field, thermal convection in melt and centrifugal pumping flows due to crystal rotation could be strongly suppressed so that the fluctuations of temperature and micro-growth rate at solid/liquid interface could be restrained effectively. In the PMCZ condition, the growing environment of SiGe bulk single crystal was similar to the crystal growth in space under the condition of micro-gravity. The motion of impurities (Ge, oxygen, etc.) had been controlled by diffusion near the solid/liquid interface. Oxygen concentraion became lower and the distribution of composition became more homogeneous along longitudinal direction and across a radial section in the grown SiGe crystal. The mechanism of PMCZ superior to MCZ was also discussed.

  16. The determination of bulk (apparent) density of plant fibres by density method

    International Nuclear Information System (INIS)

    The absolute density of plant fibres excludes all pores and lumen and therefore is a measure of the solid matter of the fibres. On the other hand the bulk density, which is being discussed here, includes all the solid matter and the pores of the fibres. In this work, the apparent density of the fibre was measured by using the Archimedes principle, which involves the immersion of a known weight of fibre into a solvent of lower density than the fibre. Toluene with a density of about 860 kg/m3 was chosen as a solvent. A tuft of fibre was weighed and recorded as Wfa. The fibre was then immersed in toluene, which wetted the fibre, and made to rest on the weighing pan submerged in the solvent and the weight of the immersed fibre was recorded as Wfs. The apparent density was then calculated using the equation. All the measurements were taken at room temperature. The fibre samples were not oven dried prior to measurement. (Author)

  17. Development and Validation of Stability Indicating RP-LC Method for Estimation of Ranolazine in Bulk and Its Pharmaceutical Formulations

    OpenAIRE

    Srilakshmi. V; Purnachanda Rao; Jayapal Gowardhane; Srinivas, G.; D. Ramachandran; Ganji Ramanaiah

    2012-01-01

    An isocratic reverse phase liquid chromatography (RP-LC) method has been developed and subsequently validated for the determination of Ranolazine in Bulk and its pharmaceutical formulation. Separation was achieved with a X-terra RP-18 ((Make: Waters Corporation; 150 mm × 4.6 mm I.D.; particle size 5 µm)) Column and Sodium di-hydrogen phosphate monohydrate buffer with Tri ethyl amine (pH adjusted to 5.0 with diluted orthophosphoric acid): Acetonitrile (600:400) v/v as eluent at a flow rate of ...

  18. RP-HPLC Method for the Determination of Cinitapride in the Presence of its Degradation Products in Bulk Drug

    OpenAIRE

    Roy, S. M. N.; Mangaonkar, Kiran V.; Desai, A. Y.; Yetal, Santosh M.

    2010-01-01

    A reverse phase HPLC method is described for the determination of cinitapride hydrogen tartrate in the presence of its degradation products in bulk drug. A drug was subjected to all stress conditions such as reduction, oxidation acidic and alkaline medium. Chromatography was recorded on an Intersil ODS-3 column using mixture of acetonitrile and phosphate buffer, pH adjusted to 6.7 in the ratio (70:30 v/v) as the mobile phase at the rate of 1.0 mL/min with detection at 260 nm. Glimepride was u...

  19. Stability Indicating HPLC Method for Estimation of S-amlodipine besylate and Nebivolol hydrochloride in Bulk Drugs and Marketed Formulation

    OpenAIRE

    G.V.S Kumar; Anusha Kolasani; Puranik S. B; Sridhar K.A

    2012-01-01

    A simple, precise and stability indicating reversed phase liquid chromatographic method was developed and validated for estimation of s-amlodipine besylate and nebivolol hydrochloride in bulk drug and marketed formulation. The separation was achieved on Zorbax C8 G (250mm x 4.6mm, 5µm) analytical column with mobile phase comprising of 0.05M Potassium di hydrogen phosphate: Acetonitrile (pH 3.0) (60:40v/v) at isocratic flow of 1.0ml/min with UV detection at 269 nm. The retention times of s-am...

  20. A Validated TLC-Densitometric Method for the Determination of Mesterolone in Bulk Material and in Tablets

    Science.gov (United States)

    Dołowy, Małgorzata; Pyka-Pająk, Alina; Filip, Katarzyna; Zagrodzka, Joanna

    2015-01-01

    Mesterolone is a synthetic androgenic steroid indicating a weak anabolic activity. A new, simple in use, and economical TLC-densitometric method in normal phase system (NP-TLC) has been developed and validated for the identification and quantitative determination of mesterolone in bulk drug and in tablet formulation. NP-TLC analysis was performed on aluminium plates precoated with silica gel 60F254 as the stationary phase using chloroform-acetone (40 : 10, v/v) as mobile phase. Densitometric analysis was carried out at λ = 745 nm after staining with phosphomolybdic acid. These conditions were found to give visible (dark blue) spot and sharp peak, respectively, for mesterolone at RF  0.75 ± 0.02 and enabled satisfactory separation of mesterolone from its related substance (potential impurity). The proposed NP-TLC-densitometric method was validated for specificity, linearity, precision, accuracy, robustness, and sensitivity according to ICH guideline and other validation requirements. The limit of detection (LOD) and limit of quantification (LOQ) were 61.0 ng·spot−1 and 184.0 ng·spot−1, respectively. The percent content of mesterolone in marketed tablet formulation was found to be 99.40% of label claim. The developed TLC-densitometric method can be successfully used in quality control of mesterolone in bulk material and also tablet formulation. PMID:26881196

  1. Development and Validation of an RP-HPLC Method for Quantitative Estimation of Eslicarbazepine Acetate in Bulk Drug and Tablets.

    Science.gov (United States)

    Singh, M; Kumar, L; Arora, P; Mathur, S C; Saini, P K; Singh, R M; Singh, G N

    2013-11-01

    A convenient, simple, accurate, precise and reproducible RP-HPLC method was developed and validated for the estimation of eslicarbazepine acetate in bulk drug and tablet dosage form. Objective was achieved under optimised chromatographic conditions on Dionex RP-HPLC system with Dionex C18 column (250×4.6 mm, 5 μm particle size) using mobile phase composed of methanol and ammonium acetate (0.005 M) in the ratio of 70:30 v/v. The separation was achieved using an isocratic elution method with a flow rate of 1.0 ml/ min at room temperature. The effluent was monitored at 230 nm using diode array detector. The retention time of eslicarbazepine acetate is found to be 4.9 min and the standard calibration plot was linear over a concentration range of 10-90 μg/ml with r(2)=0.9995. The limit of detection and quantification were found to be 3.144 and 9.52 μg/ml, respectively. The amount of eslicarbazepine acetate in bulk and tablet dosage form was found to be 99.19 and 97.88%, respectively. The method was validated statistically using the percent relative standard deviation and the values are found to be within the limits. The recovery studies were performed and the percentage recoveries were found to be 98.33± 0.5%. PMID:24591752

  2. Development and validation of an RP-HPLC method for quantitative estimation of eslicarbazepine acetate in bulk drug and tablets

    Directory of Open Access Journals (Sweden)

    M Singh

    2013-01-01

    Full Text Available A convenient, simple, accurate, precise and reproducible RP-HPLC method was developed and validated for the estimation of eslicarbazepine acetate in bulk drug and tablet dosage form. Objective was achieved under optimised chromatographic conditions on Dionex RP-HPLC system with Dionex C18 column (250×4.6 mm, 5 μm particle size using mobile phase composed of methanol and ammonium acetate (0.005 M in the ratio of 70:30 v/v. The separation was achieved using an isocratic elution method with a flow rate of 1.0 ml/ min at room temperature. The effluent was monitored at 230 nm using diode array detector. The retention time of eslicarbazepine acetate is found to be 4.9 min and the standard calibration plot was linear over a concentration range of 10-90 μg/ml with r 2 =0.9995. The limit of detection and quantification were found to be 3.144 and 9.52 μg/ml, respectively. The amount of eslicarbazepine acetate in bulk and tablet dosage form was found to be 99.19 and 97.88%, respectively. The method was validated statistically using the percent relative standard deviation and the values are found to be within the limits. The recovery studies were performed and the percentage recoveries were found to be 98.33± 0.5%.

  3. Uranium speciation in biofilms studies by laser fluorescence techniques

    International Nuclear Information System (INIS)

    Biofilms may immobilize toxic heavy metals in the environment and thereby influence their migration behaviour. The mechanisms of these processes are currently not understood, because the complexity of such biofilms creates many discrete geochemical microenvironments which may differ from the surrounding bulk solution in their bacterial diversity, their prevailing geochemical properties, e.g. pH and dissolved oxygen concentration, the presence of organic molecules, e.g. metabolites, and many more, all of which may affect metal speciation. To obtain such information, which is necessary for performance assessment studies or the development of new cost-effective strategies for cleaning waste waters, it is very important to develop new non-invasive methods applicable to study the interactions of metals within biofilm systems. Laser fluorescence techniques have some superior features, above all very high sensitivity for fluorescent heavy metals. An approach combining confocal laser scanning microscopy and laser-induced fluorescence spectroscopy for study of the interactions of biofilms with uranium is presented. It was found that coupling these techniques furnishes a promising tool for in-situ non-invasive study of fluorescent heavy metals within biofilm systems. Information on uranium speciation and uranium redox states can be obtained.

  4. Simple and sensitive spectrophotometric methods for the analysis of mesalamine in bulk and tablet dosage forms

    Directory of Open Access Journals (Sweden)

    Bala Sekaran Chandra

    2011-01-01

    Full Text Available Three simple, sensitive, economical and reproducible spectrophotometric methods (A, B and C are described for determination of mesalamine in pure drug as well as in tablet dosage forms. Method A is based on the reduction of tungstate and/or molybdate in Folin Ciocalteu's reagent; method B describes the reaction between the diazotized drug and α-naphthol and method C is based on the reaction of the drug with vanillin, in acidic medium. Under optimum conditions, mesalamine could be quantified in the concentration ranges, 1-30, 1-15 and 2-30 µg mL-1 by method A, B and C, respectively. All the methods have been applied to the determination of mesalamine in tablet dosage forms. Results of analysis are validated statistically.

  5. Extractive Spectrophotometric Methods for the Determination of Zolmitriptan in Bulk Drug and Pharmaceutical Formulation Using Bromocresol Green

    Science.gov (United States)

    Prashanth, K. N.; Swamy, N.; Basavaiah, K.

    2013-11-01

    Considering the basic property of zolmitriptan (ZMT) to generate ion-pairs with sulfonephthalein dyes two methods have been developed for its assay in bulk drug and dosage form. The first method (method A) is based on the formation of a colored ion-pair complex (1:1 drug:dye) of ZMT with bromocresol green (BCG) at pH 4.20 ± 0.01 and extraction of the complex into chloroform followed by measurement of the yellow ion-pair complex at 435 nm. In the second method (method B), the drug-dye ion-pair complex was treated with ethanolic potassium hydroxide in ethanolic medium and the resulting base form of the dye was measured at 630 nm. Beer's law was obeyed in the concentration range of 0.8-18.0 and 0.08-1.4 μg/ml for method A and B, respectively, and the corresponding molar absorptivity values were 1.50ṡ104 and 1.52ṡ105 l/(molṡcm). The Sandell sensitivity values were 0.0191 and 0.0019 μg/cm2 for method A and method B, respectively. The stoichiometry of the ion-pair complex formed between the drug and dye (1:1) was determined by Job's continuous variation method and the stability constant of the complex was also calculated. The proposed method was successfully extended to dosage form (tablets).

  6. STABILITY INDICATING RP-LC METHOD FOR DETERMINATION OF RASAGILINE MESYLATE IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    R. Narendra Kumar

    2010-10-01

    Full Text Available An isocratic stability indicating liquid chromatographic method has been developed and validated for the determination of Rasagiline in bulk drug and its pharmaceutical dosage forms. Separation of the drug with degradation products was achieved using Puroshere Star, C18, 150 x 4.6mm; 5μm column as stationary phase and pH 7.0(±0.05 buffer: Acetonitrile (40:60,v/v as mobile phase at a flow rate of 1.0 mL/min. UV detection was performed at 210 nm. The method is linear over the range of 4.8 – 150.5 μg/mL. The percent recovery of drug in dosage forms was ranged from 98.0 to 102.1. The method is simple, rapid, precise, selective and stability indicating and can be used for the assay in quality control and stability studies samples.

  7. The EU network on trace element speciation in full swing

    DEFF Research Database (Denmark)

    Cornelis, R.; Camara, C.; Ebdon, L.;

    2000-01-01

    The EC-funded thematic network 'Speciation 21' links scientists in analytical chemistry working in method development for the chemical speciation of trace elements, and potential users from industry and representatives of legislative agencies, in the field of environment, food and occupational...

  8. Theoretical studies of gene substitution, geographic variation, and speciation

    Energy Technology Data Exchange (ETDEWEB)

    Felsenstein, J.

    1977-07-31

    Brief comments are given on the results of a research program dealing with population genetics of evolutionary processes. The various subjects studied included genetic variation in clines; speciation and disruptive selection; parapatric speciation in clines; macroevolutionary laws in a model ecosystem; migration matrices; lethal allelism; estimation of number of loci in quantitative inheritance; numerical taxonomy methods; and new mutants in Lesch-Nyhan disease.

  9. Simultaneous Estimation of Fluoxetine HCl and Olanzapine in Bulk Drug and Pharmaceutical Formulation by Using UV-Visible Spectroscopy Method

    Directory of Open Access Journals (Sweden)

    Rubesh kumar S

    2011-01-01

    Full Text Available Present work is to carry out an analytical method development and validation of Fluoxetine HCl (FLU and Olanzapine (OLZ in bulk drug and pharmaceutical dosage form. The developed method is based upon simultaneous equations (Vierodt’s method by using UV/Visible spectroscopy. Both drugs come in the categories of anti- depressant and anti-psychotic agent. The developed method can be used for the simultaneous estimation of FLU and OLZ in pharmaceutical dosage form without separating from each other or from the excipients. Primarily the λ max of Fluoxetine HCl (FLU and Olanzapine (OLZ was determined as 226 and 258 nm respectively. The suggested method is validated by using ICH validation parameters like accuracy, precession, linearity and LOD and LOQ respectively. Accuracy study showed percentage recovery in the range of 97-102% w/w respectively. Precision studies were carried out for 6 successive absorbance and studied for their percentage relative standard deviation (%RSD was < 2%, LOD and LOQ was studied and the limit of detection and limit of quantification were found to be was 1-100 µg/ml for Olanzapine and Fluoxetine HCl, the slope of interception Y=0.23x6+0.054 (R2 0.993 and Y=0.222x6-0.014 (R 2 0.995 respectively. Relative standard deviation for Fluoxetine hydrochloride and Olanzapine were 0.4904 and 0.53969, the co-relation coefficient were 0.997 and 0.825 respectively. This procedure was applied successfully for the analysis of FLU and OLZ in bulk drug and Pharmaceutical preparations.

  10. Development and validation spectroscopic methods for the determination of lomefloxacin in bulk and pharmaceutical formulations

    Science.gov (United States)

    El-Didamony, A. M.; Hafeez, S. M.

    2016-01-01

    Four simple, sensitive spectrophotometric and spectrofluorimetric methods (A-D) for the determination of antibacterial drug lomefloxacin (LMFX) in pharmaceutical formulations have been developed. Method A is based on formation of ternary complex between Pd(II), eosin and LMFX in the presence of methyl cellulose as surfactant and acetate-HCl buffer pH 4.0. Spectrophotometrically, under the optimum conditions, the ternary complex showed absorption maximum at 530 nm. Methods B and C are based on redox reaction between LMFX and KMnO4 in acid and alkaline media. In indirect spectrophotometry method B the drug solution is treated with a known excess of KMnO4 in H2SO4 medium and subsequent determination of unreacted oxidant by reacting it with safronine O in the same medium at λmax = 520 nm. Direct spectrophotometry method C involves treating the alkaline solution of LMFX with KMnO4 and measuring the bluish green product at 604 nm. Method D is based on the chelation of LMFX with Zr(IV) to produce fluorescent chelate. At the optimum reaction conditions, the drug-metal chelate showed excitation maxima at 280 nm and emission maxima at 443 nm. The optimum experimental parameters for the reactions have been studied. The validity of the described procedures was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed methods were successfully applied for the determination of the selected drug in pharmaceutical preparations with good recoveries.

  11. Kinetic Spectrophotometric Method for the Quantitation of Telithromycin in Bulk and Drug Formulation

    Directory of Open Access Journals (Sweden)

    Abou Attia F. M.

    2010-10-01

    Full Text Available A kinetic method for the accurate and sensitive determination of telithromycin has been described. The method is based on the oxidation of telithromycin with alkaline KMnO4. At a fixed time of 24 min. the formed magnate ion is spectrophotometrically measured at 610 nm. The concentration of telithromycin is calculated using the calibration equation for the fixed time and initial rate methods. Beer´s law was obeyed from 3.24-12.9µg ml-1 The assays limits of detection were 0.2-0.70µg ml-1 and the R.S.D. (n= 5 was 0.6 %. Recovery was 99.8 and 100.83%. The analytical performance of the, in terms of accuracy and precision, were statistically validated, the results were satisfactory RSD ≤ 2%. The method has been applied successfully to commercial tablet dosage form. Statistical comparison of the result with the reference method showed excellent agreement and proved that no significant difference in the accuracy and precision.

  12. Development of a non-chromatographic method for the speciation analysis of inorganic antimony in mushroom samples by hydride generation atomic fluorescence spectrometry

    Science.gov (United States)

    Sousa Ferreira, Hadla; Costa Ferreira, Sergio Luis; Cervera, M. Luisa; de la Guardia, Miguel

    2009-06-01

    A simple and sensitive method has been developed for the direct determination of toxic species of antimony in mushroom samples by hydride generation atomic fluorescence spectrometry (HG AFS). The determination of Sb(III) and Sb(V) was based on the efficiency of hydride generation employing NaBH 4, with and without a previous KI reduction, using proportional equations corresponding to the two different measurement conditions. The extraction efficiency of total antimony and the stability of Sb(III) and Sb(V) in different extraction media (nitric, sulfuric, hydrochloric, acetic acid, methanol and ethanol) were evaluated. Results demonstrated that, based on the extraction yield and the stability of extracts, 0.5 mol L - 1 H 2SO 4 proved to be the best extracting solution for the speciation analysis of antimony in mushroom samples. The limits of detection of the developed methodology were 0.6 and 1.1 ng g - 1 for Sb(III) and Sb(V), respectively. The relative standard derivation was 3.8% (14.7 ng g - 1 ) for Sb(V) and 5.1% (4.6 ng g - 1 ) for Sb(III). The recovery values obtained for Sb(III) and Sb(V) varied from 94 to 106% and from 98 to 105%, respectively. The method has been applied to determine Sb(III), Sb(V) and total Sb in five different mushroom samples; the Sb(III) content varied from 4.6 to 11.4 ng g - 1 and Sb(V) from 14.7 to 21.2 ng g - 1 . The accuracy of the method was confirmed by the analysis of a certified reference material of tomato leaves.

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

    Directory of Open Access Journals (Sweden)

    Alankar Shrivastava

    2011-01-01

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

  14. A NEW RP-HPLC METHOD DEVELOPMENT AND VALIDATION OF ORLISTAT IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    N.Sreekanth,

    2010-07-01

    Full Text Available A simple, accurate and rapid RP-HPLC method has been developed for the estimation of Orlistat (ORL in bulk and pharmaceutical dosage forms using a C 18 column 150 x 4.6 mm i.d, 3.5m particle sizein isocratic mode, with mobile phase comprising of acetonitrile, water and phosphoric acid in the ratio of 85:15:0.5 (v/v/v. The flow rate was 1ml/min and detection was carried out by UV detector at 205nm. The retention time for ORL was found to be 3.79 min. The proposed method has permitted the quantification of ORL over linearity in the range of 6-60μg/ml and its percentage recovery was found to be 99.78-100.27%. The % RSD of intra day and inter day precision were found 0.49% and 0.57%, respectively.

  15. Formation of P3KHT:PCBM bulk-heterojunction using orthogonal solvents by ultrasonic spray method

    International Nuclear Information System (INIS)

    Bulk-heterojunction (BHJ) morphologies with pure domains and sharp interfaces can lead to a more pronounced photovoltaic performance in organic solar cells. In this paper we report the formation of bulk-heterojunction of P3KHT (poly [3-(sodium-6 hexanoate) thiophene-2, 5-diyl]) and PCBM (phenyl-C61-butyric acid methyl ester) using orthogonal solvents by the ultrasonic spray method, which can lead to pure phases and sharp interfaces. P3KHT and PCBM are soluble in water and chlorobenzene respectively, which are orthogonal solvents. The modelling and simulation of the ultrasonic spray method is reported, and shows the possibility of formation of interconnecting phases of the two components in P3KHT:PCBM BHJ, formed using orthogonal solvents, if specific process parameters are chosen. The modelling and simulation also presents a way to determine optimum parameter space in an intermittent spray deposition method using orthogonal solvents. P3KHT:PCBM BHJ has been prepared using three different approaches. Significant photoluminescence quenching, suggesting efficient excitons separation before recombination has been observed in BHJ prepared by the ‘emulsion of solutions’ method. The study of the optical properties of P3KHT:PCBM BHJ suggests that the BHJ may contain bilayer type structures embedded in the BHJ morphology, which is further confirmed by complementary experiments. This new approach to preparing BHJ with pure phase domains and sharp donor/acceptor interfaces may find applications in optoelectronic devices such as organic thin-film transistors, photodetectors, organic light emitting diodes and organic solar cells. (paper)

  16. Gamma-ray self-attenuation correction for bulk samples by Monte-Carlo method

    International Nuclear Information System (INIS)

    When comparative method is adopted in gamma-ray spectrometry measurements of environmental samples, self-attenuation correction of under test samples is necessary, because of different self-attenuation coefficients of the reference and test samples. In this work, we investigate the self-attenuation correction by finding the relationship between the transmissivity and self-attenuation at the same photo-peak. The parameters of HPGe detector crystal were obtained by point source experiments. Based on these parameters, the relationship between the transmissivity and self-attenuation were studied by using the MCNP code. The differences of density and chemical composition were taken into account. This results show that method can be used to estimate the self-attenuation correction of complicated matrix samples. (authors)

  17. Structure and performance of polymer-derived bulk ceramics determined by method of filler incorporation

    International Nuclear Information System (INIS)

    The effect of four distinct methods of incorporating fillers into a preceramic polymer matrix was investigated with respect to the structural and mechanical properties of the resulting materials. Investigations were conducted with a polysiloxane/Al2O3/ZrO2 model system used as a precursor for mullite/ZrO2 composites. A quantitative evaluation of the uniformity of filler distribution was obtained by employing a novel image analysis. While solvent-free mixing led to a heterogeneous distribution of constituents resulting in limited mechanical property values, a strong improvement of material homogeneity and properties was obtained by using solvent-assisted methods. The results demonstrate the importance of the processing route on final characteristics of polymer-derived ceramics

  18. Structure and performance of polymer-derived bulk ceramics determined by method of filler incorporation

    Science.gov (United States)

    Konegger, T.; Schneider, P.; Bauer, V.; Amsüss, A.; Liersch, A.

    2013-12-01

    The effect of four distinct methods of incorporating fillers into a preceramic polymer matrix was investigated with respect to the structural and mechanical properties of the resulting materials. Investigations were conducted with a polysiloxane/Al2O3/ZrO2 model system used as a precursor for mullite/ZrO2 composites. A quantitative evaluation of the uniformity of filler distribution was obtained by employing a novel image analysis. While solvent-free mixing led to a heterogeneous distribution of constituents resulting in limited mechanical property values, a strong improvement of material homogeneity and properties was obtained by using solvent-assisted methods. The results demonstrate the importance of the processing route on final characteristics of polymer-derived ceramics.

  19. MATHEMATICAL OPTIMIZATION METHODS TO ESTABLISH ACTIVE PHASES ON HETEROGENEOUS CATALYSIS: CASE OF BULK TRANSITION METAL SULPHIDES

    Directory of Open Access Journals (Sweden)

    Iván Machín

    2015-03-01

    Full Text Available This paper presents a set of procedures based on mathematical optimization methods to establish optimal active sulphide phases with higher HDS activity. This paper proposes a list of active phases as a guide for orienting the experimental work in the search of new catalysts that permit optimize the HDS process. Studies in this paper establish Co-S, Cr-S, Nb-S and Ni-S systems have the greatest potential to improve HDS activity.

  20. A Stability Indicating U-HPLC Method for Milnacipran in Bulk Drugs and Pharmaceutical Dosage Forms

    OpenAIRE

    K.V. Surendranath; Shakil S. Sait; Naresh Tondepu; Ravi Kiran Kaja; Suresh Kumar

    2012-01-01

    The objective of the current study was to develop a validated, specific and stability-indicating reverse phase UHPLC method for the quantitative determination of Milnacipran and its related substances. The determination was done for active pharmaceutical ingredient and its pharmaceutical dosage forms in the presence of degradation products, and its process-related impurities. The drug was subjected to stress conditions of hydrolysis (acid and base), oxidation, pho- tolysis and thermal degrada...

  1. Simultaneous Estimation of Ibuprofen and Phenylephrine Hydrochloride in Bulk and Combined Dosage Form by First Derivative UV Spectrophotometry Method

    Directory of Open Access Journals (Sweden)

    Mehul Patel

    2013-01-01

    Full Text Available A simple, precise, rapid, and economic method was developed for the simultaneous determination of Ibuprofen and Phenylephrine HCl in bulk and combined dosage form. This method involves first-order derivative spectroscopy using 248 nm and 237 nm as zero crossing points for Ibuprofen and Phenylephrine HCl, respectively. For spectrophotometric method 0.1 N NaOH was used as a solvent. The linearity was established over the concentration range of 12–72 μg/mL and 1.5–22 μg/mL for Ibuprofen and Phenylephrine HCl with correlation coefficient (r2 of 0.9972 and 0.9981, respectively. The mean % recoveries were found to be in the range of 98.88% and 98.54% for Ibuprofen and Phenylephrine HCl, respectively. Interday and intraday studies showed repeatability of the method. The method was found to be specific and robust. The method was successfully applied to pharmaceutical formulation, with no interference from excipients as indicated by the recovery study. Results of analysis were validated statistically and by recovery studies.

  2. DEVELOPMENT AND VALIDATION OF A UV SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF LISINOPRIL BOTH IN BULK AND MARKETED DOSAGE FORMULATIONS

    Directory of Open Access Journals (Sweden)

    Vijayalaxmi Chavan

    2015-02-01

    Full Text Available Lisinopril is angiotensin converting enzyme inhibitor widely used in management of blood pressure and congestive heart failure. This study proposes a simple, rapid and economic method of analysis of lisinopril in bulk as well as in formulation using UV spectrophotometer. The present method has been developed in distil water which makes it economic and reproducible. Absorption maxima was obtained at 206nm. The method is validated using ICH Q2R1 guideline for various parameters like precision, accuracy, limit of detection, limt of quantitation etc. Drug follows lineariy in concentration range 10-50 μg/ml with correlation coefficient value (r2 0.999. The accuracy study was performed by recovery checking at three different concentrations i.e., 80%, 100% and 120 %. The % recovery was found to be in the range 99.27%– 99.95%. The precision of the method was studied as an intra-day, inter-day variations and repeatability. The % R.S.D. value less than 2 indicate that the method is precise. The proposed method is a cost-effective quality-control tool for routine analysis of lisinopril in pharmaceutical dosage form.

  3. A novel validated UPLC method for quantitation of lopinavir and ritonavir in bulk drug and pharmaceutical formulation with its impurities

    Directory of Open Access Journals (Sweden)

    Gnana Deepika Killi

    2014-04-01

    Full Text Available A simple gradient Ultra Performance liquid chromatographic method (UPLC was developed for determination of lopinavir and ritonavir from its related impurities and assay for the first time. This method involves the use of a C18 (Acquity UPLC BEH C18, 50 × 2.1 mm, 1.7 µm column thermostated at 30 oC using triethylamine (pH 2.2: 0.1% H3PO4 in acetonitrile and methanol (85:15 as mobile phase in gradient elution mode. A Photo Diode Array (PDA detector set at 215 nm was used for detection with flow rate 0.4 mL/min. This method was validated over the range of limit of quantitation (LOQ to 50 to 150% of impurity specification limit and of working concentration for assay. The developed method was validated for linearity, range, precision, accuracy and specificity. This method was successfully applied for content determination of lopinavir and ritonavir in pharmaceutical formulations. This method can be conveniently used in quality control laboratory for routine analysis for assay and related substances as well as for evaluation of stability samples of bulk drugs and pharmaceutical formulations.

  4. Changes in zinc speciation with mine tailings acidification in a semi-arid weathering environment

    Science.gov (United States)

    Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon

    2011-01-01

    High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semi-arid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6,000 to 450 mg kg−1) and plant-available (590 to 75 mg kg−1) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and micro-focused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn0.8talc), Zn sorbed to ferrihydrite (ZnadsFeOx), and zinc sulfate (ZnSO4·7H2O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly-crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Micro-scale analyses identified hetaerolite (ZnMn2O4), hemimorphite (Zn4Si2O7(OH)2·H2O) and sphalerite (ZnS) as minor phases. Bulk and micro-focused spectroscopy complement the chemical extraction results and highlight the importance of using a multi-method approach to interrogate complex tailings systems. PMID:21761897

  5. Bulk Modulus of Spherical Palladium Nanoparticles by Chen-Mobius Lattice Inversion Method

    Science.gov (United States)

    Abdul-Hafidh, Esam

    2015-03-01

    Palladium is a precious and rare element that belongs to the Platinum group metals (PGMS) with the lowest density and melting point. Numerous uses of Pd in dentistry, medicine and industrial applications attracted considerable investment. Preparation and characterization of palladium nanoparticles have been conducted by many researchers, but very little effort has taken place on the study of Pd physical properties, such as, mechanical, optical, and electrical. In this study, Chen-Mobius lattice inversion method is used to calculate the cohesive energy and modulus of palladium. The method was employed to calculate the cohesive energy by summing over all pairs of atoms within palladium spherical nanoparticles. The modulus is derived from the cohesive energy curve as a function of particles' sizes. The cohesive energy has been calculated using the potential energy function proposed by (Rose et al., 1981). The results are found to be comparable with previous predictions of metallic nanoparticles. This work is supported by the Royal commission at Yanbu- Saudi Arabia.

  6. Efficient Execution Methods of Pivoting for Bulk Extraction of Entity-Attribute-Value-Modeled Data.

    Science.gov (United States)

    Luo, Gang; Frey, Lewis J

    2016-03-01

    Entity-attribute-value (EAV) tables are widely used to store data in electronic medical records and clinical study data management systems. Before they can be used by various analytical (e.g., data mining and machine learning) programs, EAV-modeled data usually must be transformed into conventional relational table format through pivot operations. This time-consuming and resource-intensive process is often performed repeatedly on a regular basis, e.g., to provide a daily refresh of the content in a clinical data warehouse. Thus, it would be beneficial to make pivot operations as efficient as possible. In this paper, we present three techniques for improving the efficiency of pivot operations: 1) filtering out EAV tuples related to unneeded clinical parameters early on; 2) supporting pivoting across multiple EAV tables; and 3) conducting multi-query optimization. We demonstrate the effectiveness of our techniques through implementation. We show that our optimized execution method of pivoting using these techniques significantly outperforms the current basic execution method of pivoting. Our techniques can be used to build a data extraction tool to simplify the specification of and improve the efficiency of extracting data from the EAV tables in electronic medical records and clinical study data management systems. PMID:25608318

  7. Electrical and Optical Properties of Bulk ZnO Single Crystal Grown by Flux Bridgman Method

    Institute of Scientific and Technical Information of China (English)

    LI Xin-Hua; XU Jia-Yue; JIN Min; SHEN Hui; LI Xiao-Min

    2006-01-01

    Zinc oxide (ZnO) single crystals are grown by the modified vertical Bridgman method using a PbF2 flux. Themaximum size of the as-grown ZnO crystal is about φ25 mm× 5mm. The transmittance of the as-grown ZnOcrystal is more than 70% in the range of 600-800nm and the optical band gap is estimated to be 3.21 eV. Thephotoluminescence spectrum indicates that the as-grown ZnO crystal has a very low concentration of nativedefects and is much closed to its stoichiometry. The electrical measurement exhibits that the ZnO crystal haslow electrical resistivity of 0.02394Ωcm-1 and a high carrier concentration of 2.10 × 1018 cm-3

  8. A novel method for the quantification, characterisation and speciation of silver nanoparticles in earthworms exposed in soil

    NARCIS (Netherlands)

    Makama, S.I.; Peters, R.J.B.; Undas, A.K.; Brink, van den N.W.

    2015-01-01

    Currently, metal engineered nanoparticles (ENPs) in tissues are generally quantified based on total concentrations after acid digestion of samples. Electron microscopy has also been used for non-quantitative characterisation of NPs in situ, and can be enhanced with tissue-processing methods that can

  9. Novel LC Method Development and Validation for Simultaneous Determination of Montelukast and Doxofylline in Bulk and Pharmaceutical Dosage Forms

    Directory of Open Access Journals (Sweden)

    Gadapa Nirupa

    2013-01-01

    Full Text Available A novel rapid HPLC method was developed for simultaneous determination of montelukast and doxofylline in bulk and pharmaceutical dosage forms. Development of an analytical method for simultaneous estimation of drugs requires a lot of efforts and of course it is a challenging task. The method was developed by using C18 (150 mm×4.6 mm, 5 μm column; mobile phase consisting of methanol and phosphate buffer at pH 4.5; the flow rate of 1.0 mL/min and ultraviolet detection at 280 nm. Both drugs were sufficiently resolved having retention time of 4.7 min and 1.9 min for montelukast and doxofylline, respectively. The method was validated as per ICH Guidelines for various parameters like precision, linearity, accuracy, ruggedness, and robustness. The validated method was applied to the commercially available pharmaceutical dosage form and obtained the desired result.

  10. Development of Stability Indicating LC Method for the Estimation of Tolperisone in Bulk and Pharmaceutical Dosage Form

    Directory of Open Access Journals (Sweden)

    U. K. Chhalotiya

    2013-01-01

    Full Text Available A rapid, specific, and sensitive reverse phase high performance liquid chromatographic method has been developed and validated for analysis of tolperisone in both bulk and pharmaceutical dosage form. The HPLC method was performed with a reversed phase C18 SunFire column (250 mm × 4.6 mm i.d., 5 mm particle size, detection at 261 nm and a mixture of methanol, water and pH 7.5 adjusted by use of 1% solution of triethylamine (60 : 40 as mobile phase. The flow rate was 1.0 mL min−1 and effluents were monitored at 261 nm. The retention time of tolperisone was 4.8 min. Tolperisone was subjected to acid and alkali hydrolysis, chemical oxidation, wet hydrolysis, dry heat degradation, and sunlight degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. Stressed samples were assayed using developed LC method. The proposed method was validated with respect to linearity, accuracy, precision, and robustness. The method was successfully applied to the estimation of tolperisone in tablet dosage forms.

  11. Mechanochemical Effects on the Synthesis of Copper Orthophosphate and cyclo-Tetraphosphate Bulks by the Hydrothermal Hot Pressing Method

    Directory of Open Access Journals (Sweden)

    Isao Tanaka

    2009-01-01

    Full Text Available Copper orthophosphate, Cu3(PO42, and cyclo-tetraphosphates, Cu2P4O12, were synthesized using phosphoric acid and basic copper carbonate, and then treated with a planetary mill for up to 360 minutes. The un-milled and milled samples were characterized by X-ray diffraction (XRD and Fourier transform infrared (FT-IR spectroscopy. SEM images, particle size distribution, specific surface area, UV-Vis reflectance spectra were also used to evaluate the materials. The un-milled and milled materials were used to fabricate copper phosphate bulks by a hydrothermal hot pressing method. The influence of powder condition on the sintering behavior of the copper phosphates was studied.

  12. Structural study of Zr-Cu-Ag bulk metallic glasses using the anomalous X-ray scattering method

    International Nuclear Information System (INIS)

    The structures of Zr45Cu45Ag10 and Zr40Cu40Ag20 bulk metallic glasses (BMGs) were investigated using the anomalous x-ray scattering and reverse Monte Carlo simulation (AXS-RMC) method. The fundamental structural features of Zr45Cu45Ag10 and Zr40Cu40Ag20 can be properly demonstrated through the common dense random packing of the hard spheres, and the addition of Ag appeared to result in no prominent formation of the particular chemical ordering units. A Voronoi analysis indicated that the fraction of the icosahedron-like coordination was the largest around the Cu in Zr45Cu45Ag10 BMG, where the best glass-forming ability was realized. The improvement in the glass-forming ability in a Zr-Cu-Ag system appears to be associated with the icosahedron-like local coordination.

  13. Bulk crystal growth of Mg2Si by the vertical Bridgman method

    International Nuclear Information System (INIS)

    Mg2Si were grown by the vertical Bridgman (VB) method in crucibles made of chemical vapor deposition (CVD) pyrolytic graphite (PG) in order to minimize the reaction and sticking of molten Mg-Si during growth. Congruent crystallization was derived from a stoichiometric melt of Mg2Si, and incongruent crystallization was derived from nonstoichiometric melts having Mg/Si ratios of 85:15, 70:30 and 60:40. Grown samples were characterized by X-ray diffraction and electron-probe microanalysis, and their power factors were calculated from the Seebeck coefficients and electrical conductivities measured from room temperature to 773 K. The grown crystals were single-crystal-like and had high Seebeck coefficients at the temperatures from 500 to 773 K. A sample derived from a stoichiometric melt had a Seebeck coefficient of -470 μV/K and the highest power factor, 7.8x10-6 W/cm K2 at 373 K, was calculated for the sample derived from a melt with an Mg/Si ratio of 70:30

  14. Searching for speciation genes

    DEFF Research Database (Denmark)

    Holt, Benjamin George; Côté, Isabelle M; Emerson, Brent C

    2011-01-01

    Closely related species that show clear phenotypic divergence, but without obvious geographic barriers, can provide opportunities to study how diversification can occur when opportunities for allopatric speciation are limited. We examined genetic divergence in the coral reef fish genus Hypoplectr...... evidence for genes that may be associated with colour morphotype in the genus Hypoplectrus....

  15. Speciation of coagulase-negative staphylococci in the clinical laboratory.

    Science.gov (United States)

    Ellner, P D; Myrick, B

    1982-04-01

    The purpose of this study was to evaluate the efficacy of the API Staph System for the speciation of coagulase-negative staphylococci. Three hundred and seventy-one coagulase-negative clinical isolates were studied; 50% of these could be speciated using the code profiles of the API System. By reference to the Kloos and Schleifer schema, 93% of the isolates could be speciated. The distribution of the various staphylococcal species in clinical specimens was determined. It was concluded that the API Staph System would be a satisfactory method of speciation if the data base could be expanded. Such speciation may at times be helpful in interpreting the significance of coagulase-negative staphylococcal isolates in the clinical laboratory. PMID:7173176

  16. Speciation of surfaces of the electrodeposited thorium by methods of alpha spectrometry and secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    The samples with the natural thorium isotope of 232Th were prepared by electrodeposition on the stainless discs from the solution Th(NO3)4.12H2O with the use of solutions of Na2SO4, NaHSO4, KOH and (NH4)2(C2O4) by electric current of 0.75 A. The prepared discs were analyzed by two methods: alpha spectrometry a secondary ion mass spectrometry. The numbers of the registered impulses for 232Th obtained from the alpha spectrometry. Activity and surface's weight was calculated from the numbers of the registered impulses for 232Th. After that, alpha spectrometry discs were analyzed by TOF-SIMS IV which is installed in the International Laser Centre in Bratislava. The integral and normalized intensities of isotope of 232Th and intensities of ions of ThO+, ThOH+, ThO2H+, Th2O4H+, ThO2-, ThO3H-, ThH3O3- a ThN2O5H- were measured. The linear correlation is between surface's weights of Th and intensities of ions of Th+ from SIMS, however the correlation coefficient has relatively low value. With SIMS method we found out that oxidized and hydride forms of thorium are significantly represented in samples with electroplated thorium. (author)

  17. Development and Validation of UV Spectrophotometric method for estimation of Dapoxetine HCL in bulk and dosage Form

    Directory of Open Access Journals (Sweden)

    Kanani Vineeta V

    2013-03-01

    Full Text Available Dapoxetine HCl, a selective serotonin reuptake inhibitor is a novel drug for premature ejaculation and no spectrophotometric method for its estimation has been reported yet. The aim of present work is to develop and validate simple, accurate, sensitive, reproducible and specific spectrophotometric method for the determination of Dapoxetine HCl, in bulk and its pharmaceutical formulations, using methanol as a solvent. The optimum conditions for the analysis of the drug were established and the developed method was validated with respect to linearity, accuracy (recovery, precision, robustness, ruggedness, LOD, LOQ and specificity. The maximum wavelength (% max was found to be 291 nm and a good linearity was observed in the concentration range of 5-60 μg/mL having regression equation, y = 0.0164x – 0.0071 with correlation coefficient of 0.9998. The percentage recovery of Dapoxetine HCl was found to be 99.5489 ±0.1599 and % CV (0.16; n=9 indicated a good precision of the analytical method. The limit of detection (LOD and limit of quantitation (LOQ were 0.0239 μg/mL and 0.0724 μg/mL, respectively. Robustness and ruggedness of the method was performed by using different % max, instruments, apparatus and analysts. The method was found to be simple, accurate, precise, reproducible, economical and robust. Analytical method validation was found to be within an acceptance criteria according to ICH Q2 R1 guidelines. The proposed method can be applied for routine quality control analysis of Dapoxetine HCl.

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

    Directory of Open Access Journals (Sweden)

    Paulo Roberto da Silva Ribeiro

    2014-09-01

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

  19. Method of aeration disinfecting and drying grain in bulk and pretreating seeds and a transverse blow silo grain dryer therefor

    Science.gov (United States)

    Danchenko, Vitaliy G.; Noyes, Ronald T.; Potapovych, Larysa P.

    2012-02-28

    Aeration drying and disinfecting grain crops in bulk and pretreating seeds includes passing through a bulk of grain crops and seeds disinfecting and drying agents including an ozone and air mixture and surrounding air, subdividing the disinfecting and drying agents into a plurality of streams spaced from one another in a vertical direction, and passing the streams at different heights through levels located at corresponding heights of the bulk of grain crops and seeds transversely in a substantially horizontal direction.

  20. Magnetic Forces Investigation of Bulk HTS over Permanent Magnetic Guideway under Different Lateral Offset with 3D-Model Numerical Method

    Directory of Open Access Journals (Sweden)

    Yiyun Lu

    2012-01-01

    Full Text Available Magnetic forces of a cylinder shape bulk high-temperature superconductor (HTS over a permanent magnet guideway (PMG are studied mathematically. One cylindrical bulk HTS with a diameter of 30 mm and 15 mm in height is used. Two types of PMG are employed for external magnetic fields consideration. The relationship of magnetic forces of bulk HTS under different lateral offsets over PMG is studied with 3D-model finite element method (FEM. The calculation results show that the maximum magnetic levitation force of bulk HTS over PMG is tightly related to the applied magnetic field distribution. For the symmetrical PMG, the maximum magnetic levitation force decreases linearly with the increase of lateral offset of the bulk sample. For the Halbach PMG, when lateral offset changes from 0 mm to 25 mm, the maximum magnetic levitation force increases with the increase of lateral offset of the bulk HTS. When the lateral offset exceeds the center of the Halbach by 25 mm, the maximum levitation force decreases rapidly with the increase of the lateral offset of the bulk sample.

  1. Actinide speciation in glass leach-layers: An EXAFS study

    International Nuclear Information System (INIS)

    Uranium L3 X-ray absorption data were obtained from two borosilicate glasses, which are considered as models for radioactive wasteforms, both before and after leaching. Surface sensitivity to uranium speciation was attained by a novel application of simultaneous fluorescence and electron-yield detection. Changes in speciation are clearly discernible, from U(VI) in the bulk to (UO2)2+-uranyl in the leach layer. The leach-layer uranium concentration variations with leaching times are also determined from the data

  2. Strategy for the mapping of interactive genes using bulked segregant analysis method and Mapmaker/Exp software

    Institute of Scientific and Technical Information of China (English)

    WU Weiren; HUANG Biguang

    2006-01-01

    A qualitative trait is usually controlled by a single gene, but it may be sometimes controlled by two or even more genes. This phenomenon is called gene interaction. Rapidly searching for linked molecular markers via bulked segregant analysis (BSA)and then constructing regional linkage map with Mapmaker/Exp has become a common approach to mapping single major genes. However, methods and computer programs developed for mapping single major genes cannot be simply applied to interactive genes because the genetic patterns of gene interactions are quite different from that of single-gene inheritance. Up to now, experimental methods for quickly screening molecular markers linked to interactive genes and statistical methods and corresponding computer softwares for simultaneously analyzing the linkage relationships of multiple molecular markers to an interactive gene have not been available. To solve this problem, in this paper, we propose a strategy for mapping interactive genes using BSA and Mapmaker/Exp. We demonstrate that Mapmaker/Exp' strategy using F2 generation (in a few cases, F3 generation is also needed). As BSA and Mapmaker/Exp have been broadly used in gene mapping studies and are well known by many researchers, the strategies proposed in this paper will be useful for practical researches.

  3. Stability indicating RP-HPLC method for the estimation of Decitabine in bulk drug and lipid based Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yub Raj Neupane

    2014-07-01

    Full Text Available The aim of our present work was to develop and validate a reverse phase high-performance liquid chromatography (RP-HPLC method for the determination of Decitabine (DCB. The developed method was further applied to observe the degradation of DCB under various stress conditions. Methods: Chromatographic separation was achieved on C18, 250 × 4.6 mm, particle size 5 μm, Agilent column, using ammonium acetate (0.01M as mobile phase with flow rate of 1mL/min and injection volume was 20 μL. Quantification was carried out with UV detector at 230 nm with a linear calibration curve in the concentration range of 10–100 μg/mL based on peak area. Thus, developed method was validated for linearity, accuracy, precision, and robustness. Results: Linearity was found to be in the range between 10–100 μg/mL with a significantly higher value of correlation coefficient r2 = 0.9994. The limits of detection (LOD and the limits of quantification (LOQ were found to be 1.92μg/mL and 5.82 μg/mL respectively. Moreover, validated method was applied to study the degradation profile of DCB under various stress degradation conditions. Examination of different stress conditions on degradation of DCB showed that its degradation was highly susceptible to oxidative condition as 31.24% of drug was degraded. In acidic and alkaline conditions, the drug was degraded by 21.03% and 12.16% respectively, while thermal and photolytic condition causes least degradation, i.e. 0.21% and 0.3% respectively. Conclusion: The proposed method was found to be sensitive, specific and was successfully applied for the estimation of DCB in bulk drug, and lipid based nanoparticles.

  4. Stability-Indicating RP-HPLC Method for Determination of Guanfacine Hydrochloride in Bulk Drugs and in Pharmaceutical Dosage Form

    Directory of Open Access Journals (Sweden)

    Vinod K. Ahirrao

    2011-04-01

    Full Text Available A novel stability-indicating RP-HPLC method was developed and validated for quantitative determination of guanfacine hydrochloride in bulk drug and in pharmaceutical dosage form. An isocratic, reversed phase HPLC method was developed to separate the drug from the degradation products, using Apollo, C18 (250mm x 4.6mm, 5µm column with mobile phase of 50mM Ammonium acetate (volatile buffer and acetonitrile (65:35, v/v. UV detection has been done at wavelength 220 nm. The guanfacine hydrochloride was subjected to the stress conditions of hydrolysis (acid, base, oxidation, photolysis and thermal degradation. The stressed samples were analyzed by the proposed method. The analyte peak shape was excellent. The described method shows excellent linearity over a range of 30 – 450 µg/mL. The correlation coefficient for guanfacine hydrochloride was 0.999. The limit of detection for Guanfacine hydrochloride is 0.011 µg/mL and the limit of quantification is 0.038 µg/mL respectively.Degradation was observed for guanfacine hydrochloride in base, thermal and in 30% H2O2 conditions. The drug was found to be stable in the other stress conditions attempted. The degradation products were well resolved from main peak. The percentage recovery of guanfacine hydrochloride was ranged from (99.2% to 100.5% in pharmaceutical dosage form. The developed method was validated with respect to the linearity, accuracy (recovery, precision, specificity and robustness. The forced degradation studies prove the stability indicating power of the method.

  5. SIMULTANEOUS ESTIMATION AND VALIDATION OF PARACETAMOL, CHLORPHENIRAMINE MALEATE AND PHENYLEPHRINE HYDROCHLORIDE IN BULK AND TABLET DOSAGE FORM BY USING DIFFERENT SPECTROPHOTOMETRIC METHOD

    Directory of Open Access Journals (Sweden)

    Hapse Sandip Appasaheb

    2013-10-01

    Full Text Available A simple, precise, accurate and economic simultaneous UV spectrophotometric method has been developed for the estimation of Paracetamol, Chlorpheniramine Maleate and Phenylephrine Hydrochloride in combination in bulk mixture and tablet. The estimation was based upon measurement of absorbance at absorbance maxima of 258 nm, 262 nm and 239 nm for Paracetamol, Chlorpheniramine Maleate and Phenylephrine Hydrochloride in methanol, respectively in bulk mixture and tablet. The Beer Lambert's law obeyed in the concentration range 4-24 μg/ml, for Paracetamol, Chlorpheniramine Maleate and Phenylephrine Hydrochloride respectively. The estimation of bulk mixture and tablet was carried out by simultaneous equation, Q-analysis and area under curve method for estimation of Paracetamol, Chlorpheniramine Maleate and Phenylephrine Hydrochloride. Recovery study was performed to confirm the accuracy of the methods. The methods were validated as per ICH guidelines.

  6. Stability Indicating HPLC Method for Estimation of S-amlodipine besylate and Nebivolol hydrochloride in Bulk Drugs and Marketed Formulation

    Directory of Open Access Journals (Sweden)

    G.V.S Kumar

    2012-10-01

    Full Text Available A simple, precise and stability indicating reversed phase liquid chromatographic method was developed and validated for estimation of s-amlodipine besylate and nebivolol hydrochloride in bulk drug and marketed formulation. The separation was achieved on Zorbax C8 G (250mm x 4.6mm, 5µm analytical column with mobile phase comprising of 0.05M Potassium di hydrogen phosphate: Acetonitrile (pH 3.0 (60:40v/v at isocratic flow of 1.0ml/min with UV detection at 269 nm. The retention times of s-amlodipine besylate and nebivolol hydrochloride was found to be 5.2 and 6.8 minutes respectively. The method was successfully validated in accordance to ICH guidelines for accuracy, precision, specificity, linearity, ruggedness and robustness. The linear regression analysis data for calibration plots showed good linear relationship in the concentration range 0.125-0.375μg/mL for s-amlodipine besylate and 0.25-0.75 for nebivolol hydrochloride. The drugs were exposed to acidic, basic, oxidation, thermal and photolytic stress degradation conditions. The resultant stressed samples were analyzed by the proposed method and was established to provide high resolution among the degradation products and the analytes. All the peaks of degraded product were resolved from the active pharmaceutical ingredient with significantly different retention time and the peak purity of analyte peaks in the stressed samples was confirmed by photodiode array detector. The method could effectively separate the drug from its degradation product; it can be employed as a stability- indicating one.

  7. Development and validation of HPTLC method for simultaneous determination of amlodipine besylate and metoprolol succinate in bulk and tablets

    Directory of Open Access Journals (Sweden)

    P S Jain

    2012-01-01

    Full Text Available A simple, selective, precise high-performance thin-layer chromatographic method for simultaneous determination of amlodipine besylate and metoprolol succinate in bulk and pharmaceutical combined dosage form was developed and validated. The method employed HPTLC aluminum plates precoated with silica gel 60F-254 (10×10 as the stationary phase. The solvent system consisted of toluene:ethyl acetate:methanol:triethylamine (4:1:1:0.4 v/v/v. The system was found to give a compact spot for amlodipine besylate (R f = 0.39±0.02 and metoprolol succinate (R f = 0.59±0.02. Densitometric analysis of amlodipine besylate and metoprolol succinate was carried out in the absorbance mode at 254 nm. Linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.9990±0.0013 with respect to peak area in the concentration range 400-1400 ng per spot for amlodipine besylate and r2 = 0.9993±0.0013 with respect to peak area in the concentration range 3800-13300 ng per spot for metoprolol succinate. The method was validated for precision, recovery and robustness. The limits of detection and quantitation were 39.99 and 121.20 ng per spot for amlodipine besylate and 234.31 and 710.03 ng per spot for metoprolol succinate, respectively. Statistical analysis proved that the method is selective, precise and accurate for the estimation of amlodipine and metoprolol.

  8. Heavy metal speciation in the composting process.

    Science.gov (United States)

    Greenway, Gillian M; Song, Qi Jun

    2002-04-01

    Composting is one of the more efficient and environment friendly methods of solid waste disposal and has many advantages when compared with landfill disposal on which the UK and Ireland are currently heavily dependent. Composting is a very complicated process involving intensive microbial activity and the detailed mechanisms of the process have yet to be fully understood. Metal speciation information can provide an insight into the metal-microbial interaction and would help in the evaluation of the quality of compost. This would facilitate the exploitation of composts in remediation of heavy metal contaminated land. In this work a systematic approach to metal speciation in compost has been taken by applying the three-step method for operationally defined metal speciation of soils and sediments, developed by the European Commission's Standards, Measurement and Testing Programme to monitor the change in metal speciation with time (up to 106 days) for four different waste composting processes. The results have shown that in general metals become less available for the first extraction step as the composting process proceeds. This implies that composting tends to redistribute the metals from more labile forms to more fixed forms which may explain why the application of composts could be useful for with heavy metal contaminated land. There are exceptions to this trend and in some cases, certain metals appear to behave differently depending on the source of the compost. PMID:11993774

  9. The speciation of marine particulate iron adjacent to active and passive continental margins

    Science.gov (United States)

    Lam, Phoebe J.; Ohnemus, Daniel C.; Marcus, Matthew A.

    2012-03-01

    We use synchrotron-based chemical-species mapping techniques to compare the speciation of suspended (1-51 μm) marine particulate iron collected in two open ocean environments adjacent to active and passive continental margins. Chemical-species mapping provides speciation information for heterogeneous environmental samples, and is especially good for detecting spectroscopically distinct trace minerals and species that could not be detectable by other methods. The average oxidation state of marine particulate iron determined by chemical-species mapping is comparable to that determined by standard bulk X-ray Absorption Near Edge Structure spectroscopy. Using chemical-species mapping, we find that up to 43% of particulate Fe in the Northwest Pacific at the depth of the adjacent active continental margin is in the Fe(II) state, with the balance Fe(III). In contrast, particulate iron in the eastern tropical North Atlantic, which receives the highest dust deposition on Earth and is adjacent to a passive margin, is dominated by weathered and oxidized Fe compounds, with Fe(III) contributing 90% of total iron. The balance is composed primarily of Fe(II)-containing species, but we detected individual pyrite particles in some samples within an oxygen minimum zone in the upper thermocline. Several lines of evidence point to the adjacent Mauritanian continental shelf as the source of pyrite to the water column. The speciation of suspended marine particulate iron reflects the mineralogy of iron from the adjacent continental margins. Since the solubility of particulate iron has been shown to be a function of its speciation, this may have implications for the bioavailability of particulate iron adjacent to passive compared to active continental margins.

  10. Speciation Analysis of Radionuclides in the Environment - NSK-B SPECIATION project report 2009

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Aldahan, Ala; Possnert, Göran;

    , sediments, particles); and (3) Intercomparison excise for speciation analysis of radionu-clides in soil and sediment. This report summarizes the work completed in the project partners’ laboratories, Method developments include: Development of an rapid and in-suit separation method for the speciation....... Speciation of radionuclides in soils and sediments includes: Sequential extraction of radionuclides in sediments and of trace elements in soil samples. Sequential extraction of radionuclides in aerosols and particles has also been performed. Further-more, sorption experiments have been performed to...... investigate the association of Pu, Am and Cs with different geological materials. The intercomparison exercises included sequential extraction of Pu, 137Cs, U, Th, and 129I in one soil and one sediment standard reference materials (NIST-4354, IAEA-375) and Pu in sediment collected from the Lake Heimdalen...

  11. Bulk-form TiCx/Ti nanocomposites with controlled nanostructure prepared by a new method: selective laser melting

    International Nuclear Information System (INIS)

    A novel selective laser melting method was applied to consolidate the high-energy ball-milled nanostructured TiCP/Ti composite powder to prepare TiCx/Ti nanocomposites in bulk form. The substoichiometric TiC0.625 with a hexagonal crystal structure acted as the reinforcing phase, having a lamellar nanostructure with an average thickness of ∼48 nm. The nanostructure of TiC0.625 was coarsened and finally disappeared on decreasing the applied linear laser energy density. Reasonable physical mechanisms and conditions for the formation of nanostructured TiCx during laser processing were proposed. It was revealed that the formation of nanoscale hexagonal structured TiC0.625 was due to the action of microscopic pressure induced by evaporative recoil and surface tension on (1 1 1) plane of the lamellar TiCx crystals. The disappearance of nanostructure of TiC0.625 at a lower laser energy input was ascribed to a decreased microscopic pressure and an elevated carbon activity in the molten pool.

  12. Systems and Methods for Implementing Bulk Metallic Glass-Based Strain Wave Gears and Strain Wave Gear Components

    Science.gov (United States)

    Hofmann, Douglas C. (Inventor); Wilcox, Brian (Inventor)

    2016-01-01

    Bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a strain wave gear includes: a wave generator; a flexspline that itself includes a first set of gear teeth; and a circular spline that itself includes a second set of gear teeth; where at least one of the wave generator, the flexspline, and the circular spline, includes a bulk metallic glass-based material.

  13. Development of accurate contact force models for use with Discrete Element Method (DEM) modelling of bulk fruit handling processes

    OpenAIRE

    Dintwa, Edward

    2006-01-01

    This thesis is primarily concerned with the development of accurate, simplified and validated contact force models for the discrete element modelling (DEM) of fruit bulk handling systems. The DEM is essentially a numerical technique to model a system of particles interacting with one another and with the system boundaries through collisions. The specific area of application envisaged is in postharvest agriculture, where DEM could be used in simulation of many unit operations with bulk fruit,...

  14. Redox speciation of final repository relevant elements using separation methods in combination with ICP mass spectrometry; Redoxspeziation von endlagerrelevanten Elementen mit Hilfe von Trennmethoden gekoppelt an ein Massenspektrometer mit induktiv gekoppeltem Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Graser, Carl-Heinrich

    2015-12-18

    The long-term safety assessment for nuclear waste repositories requires a detailed understanding of the chemistry of actinide elements in the geosphere. The development of advanced analytical tools is required to gain detailed insights into actinide redox speciation in a given system. The mobility of radionuclides is mostly determined by the geochemical conditions which control the redox state of radionuclides. Besides the longlived radionuclides plutonium (Pu) and neptunium (Np), which are key elements in high level nuclear waste, iron (Fe) represents a main component in natural systems controlling redox related geochemical processes. Analytical techniques for determining oxidation state distribution for redox sensitive radionuclides and other metal ions often have a lack of sensitivity. The detection limits of these methods (i.e. UV/vis, TRLFS, XANES) are in general in the range of ≥ 10{sup -6} mol.L{sup -1}. As a consequence ultrasensitive new analytical techniques are required. Capillary electrophoresis (CE) and ion chromatography (IC) are powerful separation methods for metal ions. In the course of this thesis different speciation method for iron, neptunium and plutonium were optimized. With the optimized setup redox speciation analysis of these elements in different samples were done. Furthermore CE hyphenated to inductively coupled plasma sector field mass spectrometry (CE - ICP - SF - MS) was used to measure the redox speciation of Pu (III, IV, V, VI), Np (IV, V, VI) and Fe (II, III) at concentrations lower than 10{sup -7} mol.L{sup -1}. CE coupling and separation parameters such as sample gas pressure, make up flow rate, capillary position, auxiliary gas flow, as well as the electrolyte system were optimized to obtain the maximum sensitivity. The methodes detection limits are 10{sup -12} mol.L{sup -1} for Np and Pu. The various oxidation state species of Pu and Np in different samples were separated by application of an acetate based electrolyte system

  15. Superconducting and mechanical properties of the bulk Bi(pb)SCCO system prepared via solid state and ammonium nitrate precipitation methods

    International Nuclear Information System (INIS)

    We have investigated the effect of preparation method on superconducting and mechanical properties of Bi(Pb)-2223 bulk samples using Bi1.85Pb0.35Sr2Ca2Cu3O10±y stoichiometry. Solid-state reaction and ammonium nitrate precipitation methods have been used for fabrication of the bulk samples. In addition, the effect of annealing time on BSCCO samples have been studied. Structural, electrical, magnetic and microhardness analyses of samples are performed by the X-ray powder diffraction (XRD), the Scanning Electron Microscopy (SEM), DC resistivity, AC susceptibility and Vickers microhardness test. The critical transition temperature, phase purity, surface morphology and crystallinity of the prepared bulk samples are compared with each other. Elasticity (E), brittleness (Bi), fracture toughness (KIC) and yield strength (Y) values are also determined according to annealing time, applied load and production parameters of materials

  16. Speciation of long-lived radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Xiaolin Hou

    2008-11-15

    This project started in November 2005 and ended in November 2008, the work and research approaches are summarized in this report. This project studied the speciation of radionuclides in environment. A number of speciation analytical methods are developed for determination of species of 129I, 99Tc, isotopes of Pu, and 237Np in seawater, fresh water, soil, sediment, vegetations, and concrete. The developed methods are used for the investigation of the chemical speciation of these radionuclides as well as their environmental behaviours, especially in Danish environment. In addition the speciation of Pu isotopes in waste samples from the decommissioning of Danish nuclear facilities is also investigated. The report summarizes these works completed in this project. Through this research project, a number of research papers have been published in the scientific journals, the research results has also been presented in the Nordic and international conference/meeting and communicated to international colleagues. Some publications are also enclosed to this report. (au)

  17. Chemical speciation of long-lived radionuclides in the environment

    International Nuclear Information System (INIS)

    This project started in November 2005 and ended in November 2008, the work and research approaches are summarized in this report. This project studied the speciation of radionuclides in environment. A number of speciation analytical methods are developed for determination of species of 129I, 99Tc, isotopes of Pu, and 237Np in seawater, fresh water, soil, sediment, vegetations, and concrete. The developed methods are used for the investigation of the chemical speciation of these radionuclides as well as their environmental behaviours, especially in Danish environment. In addition the speciation of Pu isotopes in waste samples from the decommissioning of Danish nuclear facilities is also investigated. The report summarizes these works completed in this project. Through this research project, a number of research papers have been published in the scientific journals, the research results has also been presented in the Nordic and international conference/meeting and communicated to international colleagues. Some publications are also enclosed to this report. (au)

  18. Ecology, sexual selection and speciation

    NARCIS (Netherlands)

    Maan, Martine E.; Seehausen, Ole

    2011-01-01

    P>The spectacular diversity in sexually selected traits among animal taxa has inspired the hypothesis that divergent sexual selection can drive speciation. Unfortunately, speciation biologists often consider sexual selection in isolation from natural selection, even though sexually selected traits e

  19. Study on the influence of X-ray tube spectral distribution on the analysis of bulk samples and thin films: Fundamental parameters method and theoretical coefficient algorithms

    International Nuclear Information System (INIS)

    Knowledge of X-ray tube spectral distribution is necessary in theoretical methods of matrix correction, i.e. in both fundamental parameter (FP) methods and theoretical influence coefficient algorithms. Thus, the influence of X-ray tube distribution on the accuracy of the analysis of thin films and bulk samples is presented. The calculations are performed using experimental X-ray tube spectra taken from the literature and theoretical X-ray tube spectra evaluated by three different algorithms proposed by Pella et al. (X-Ray Spectrom. 14 (1985) 125-135), Ebel (X-Ray Spectrom. 28 (1999) 255-266), and Finkelshtein and Pavlova (X-Ray Spectrom. 28 (1999) 27-32). In this study, Fe-Cr-Ni system is selected as an example and the calculations are performed for X-ray tubes commonly applied in X-ray fluorescence analysis (XRF), i.e., Cr, Mo, Rh and W. The influence of X-ray tube spectra on FP analysis is evaluated when quantification is performed using various types of calibration samples. FP analysis of bulk samples is performed using pure-element bulk standards and multielement bulk standards similar to the analyzed material, whereas for FP analysis of thin films, the bulk and thin pure-element standards are used. For the evaluation of the influence of X-ray tube spectra on XRF analysis performed by theoretical influence coefficient methods, two algorithms for bulk samples are selected, i.e. Claisse-Quintin (Can. Spectrosc. 12 (1967) 129-134) and COLA algorithms (G.R. Lachance, Paper Presented at the International Conference on Industrial Inorganic Elemental Analysis, Metz, France, June 3, 1981) and two algorithms (constant and linear coefficients) for thin films recently proposed by Sitko (X-Ray Spectrom. 37 (2008) 265-272)

  20. Electrochemical metal speciation in natural and model polyelectrolyte systems.

    OpenAIRE

    Hoop, van den, M.A.G.T.

    1994-01-01

    The purpose of the research described in this thesis was to examine the applicability of electro-analytical techniques in obtaining information on the speciation of metals, i.e. their distribution over different physico-chemical forms, in aquatic systems containing charged macromolecules. In chapter 1 a general introduction is given to (i) metal speciation in aquatic systems, (ii) (bio)polyelectrolytes and their counterion distributions and (iii) electrochemical methods emphasizing their apll...

  1. Surface, interface and bulk electronic structure of some Pd-Ti systems by a tight-binding method

    OpenAIRE

    Pick, Š.; Mikušik, P.

    1992-01-01

    Properties of the bulk and (111) surface of the Pd3Ti alloy and some related Ti-Pd systems are studied by using a simple LCAO model. The sign and magnitude of core level shifts (CLS) at particular atoms are correlated with initial state effects. Considerable positive CLS are predicted for the surface and especially for the bulk Ti and Pd atoms, respectively, in the Pd3Ti phase. Origin of these CLS as well as their relation to experimental findings are discussed. Local densities of electronic ...

  2. Growth of Ce:LiYF4 bulk single crystal with high Ce concentration by Cz method and the scintillation properties

    International Nuclear Information System (INIS)

    Ce 2% doped LiYF4 [Ce:LYF] bulk single crystal was grown by Czochralski method and the structural phase, crystallinity, optical properties and scintillation properties were investigated. Grown Ce:LYF bulk single crystal included some cracks in the initial part of crystal and meanwhile there were no visible cracks in the center and end parts. Full width of half maximum of X-ray rocking curve on the plate crystal in center part of Ce:LYF bulk single crystal was 81.4 arcsec. Alpha-ray position in the pulse-height spectra under alpha-ray irradiation was almost quarter that of Li-glass(GS20). Decay times of the crystals in center and end parts were 69.9 and 58.3 ns, respectively (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Growth of Ce:LiYF{sub 4} bulk single crystal with high Ce concentration by Cz method and the scintillation properties

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Yuui; Yamaji, Akihiro; Kurosawa, Shunsuke [Institute for Materials Research, Tohoku University, Sendai, 9808577 Miyagi (Japan); Kawaguchi, Noriaki; Fukuda, Kentaro [Tokuyama Corp., Sendai, 9893204 Miyagi (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, Sendai, 9808577 Miyagi (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, 9893204 Miyagi (Japan)

    2012-12-15

    Ce 2% doped LiYF4 [Ce:LYF] bulk single crystal was grown by Czochralski method and the structural phase, crystallinity, optical properties and scintillation properties were investigated. Grown Ce:LYF bulk single crystal included some cracks in the initial part of crystal and meanwhile there were no visible cracks in the center and end parts. Full width of half maximum of X-ray rocking curve on the plate crystal in center part of Ce:LYF bulk single crystal was 81.4 arcsec. Alpha-ray position in the pulse-height spectra under alpha-ray irradiation was almost quarter that of Li-glass(GS20). Decay times of the crystals in center and end parts were 69.9 and 58.3 ns, respectively (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Analyses of Heavy Metal Contents in the Bulk Atmospheric Aerosols Simultaneously Collected at Okinawa Archipelago, Japan by Using X-ray fluorescence spectrometric method (XRF)

    Science.gov (United States)

    Oshiro, Y.; ITOH, A.; Azechi, S.; Somada, Y.; Handa, D.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

    2012-12-01

    We studied heavy metal contents of bulk atmospheric aerosols using an X-ray fluorescence spectrometric method (XRF). The XRF method enables us to analyze heavy metal contents in the bulk aerosols rapidly without any chemical pretreatments. We used an energy dispersive X-ray fluorescence spectrometer that is compact and portable. We prepared several different amounts of standard reference materials (referred to "SRM", NIES No.28 of Japanese National Institute of Environmental Studies) on quartz filters for calibration curves in two different methods; 1) water-insoluble materials were collected after dispersing SRM in pure water and filtered with the quartz filters ("wet method"), and 2) SRM was dispersed in air in the plastic container and the aerosols were collected by using the low-volume air sampler ("dry method"). Good linear relationships between X-ray intensity and amount of aerosols on the filter were seen in the following 9 metals; Al, K, Ti, V, Fe, Ni, Rb, Ba, and Pb (with wet method) and 12 metals; K, Ti, Fe, Ni, Rb, Ba, Pb, Sr, Ca, Mn, Zn, and Cu (with dry method). Furthermore, we evaluated quantitative responses of XRF method by comparing with the metal contents determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after acid-digestion. We then used XRF method to determine heavy metal contents in authentic atmospheric aerosols collected in Okinawa islands, Japan. We simultaneously collected bulk aerosol samples by using identical high-volume air samplers at 3 islands; Cape Hedo Atmospheric Aerosol Monitoring Station (CHAAMS, Okinawa island), Kume island (ca. 160 km south-west of CHAAMS), and Minami-Daitou island (ca. 320 km south-east of CHAAMS). We report and discuss spatial and temporal distribution of heavy metals determined by the XRF method in the bulk atmospheric aerosols collected at the three islands during June 2008 to June 2010, and for CHAAMS during June 2008 to October 2012.

  5. Simultaneous speciation analysis using neutron activation

    International Nuclear Information System (INIS)

    Full text: Neutron activation analysis (NAA) is a well-established analytical technique for the simultaneous determination of multielement concentrations. Although various forms of NAA have been traditionally applied to measuring the total concentrations of elements, the scope of NAA can be further extended in conjunction with pre-irradiation chemical separations to determine the species of an element. The technique can then be called speciation NAA (SNAA). Since much of the toxicity of an element depends on its physico-chemical forms, there is an increasing interest in studying its speciation. A number of characteristic features of NAA, which other techniques normally do not possess, can be advantageously exploited in SNAA. For example, SNAA has simultaneous multielement specificity unlike AAS and AFS. The SNAA technique can be applied to the simultaneous speciation of elements which are not chemically similar such as Cd, Se and I, as well as to the elements such as Cl, Br and I which are rather difficult to determine by most other techniques. Qualitative as well as quantitative analysis of small samples can be done by SNAA with excellent precision, accuracy, sensitivity, and rapidity. Unlike many other techniques, SNAA has some enhanced quality assurance capabilities. We have developed SNAA methods for separating various inorganic and organic arsenic species in water and in sea foods. We are presently extending these methods to include simultaneous speciation of As, Sb and Se. We have also developed SNAA methods employing biochemical techniques for the characterization of metalloproteins and protein-bound trace element species of Se along with Cd, Cu, Mn, Mo and Zn in bovine kidneys. Lately, we have concentrated our efforts to develop SNAA methods in conjunction with HPLC, RPC, SEC, NMR and MS for the simultaneous separation and characterization of extractable organo chlorine, organo bromine and organo iodine species in fisheries samples. An overview of the

  6. Speciation of uranium in environmental relevant compartments

    International Nuclear Information System (INIS)

    In the past, the chemistry of uranium was focused on its mining and milling for production of high pure uranium compounds as initial matter of reactor fuel elements for energy production and breeding of plutonium for weapons production. In this sense, the recovery of uranium and plutonium from the used reactor fuel elements was also technical realized. The increasing input of uranium into bio-sphere by mining and milling and industrial processes like production of cement, fossil fuels, and fertilizers has led to the realization of the importance of uranium environmental chemistry. For a better assessment of radiotoxicity and transport along the food chain knowledge about the chemistry of uranium is needed in all involved compartments. Starting from uranium content in geo- and bio-systems, about the determination of chemical behavior - the speciation of uranium - is reported in selected environmental compartments like seepage waters coming from mine tailings, different kinds of bacteria living in uranium contaminated soils, and relevant forage plants growing on these soils. For uranium speciation determination direct non-invasive methods are used like various laser spectroscopic methods, and X-ray absorption spectroscopy with synchrotron radiation source, The results obtained by spectroscopic methods showed that the speciation of uranium is dominated in surface waters by uranyl-carbonate complexes in opposite to the speciation in bacteria and plants. In these compartments the speciation is dominated by binding of uranium on carboxylic and phosphorous containing functional groups. It was shown, that in the investigated systems the speciation strongly depends on different physical chemical parameters like ionic strength, kind and amount of ligands, pH, Eh e.g. In experiments with living organisms it is necessary to characterize the state of the bio-system in dependence of the used parameters to compare the obtained results (ratio of dead or living cells of bacteria

  7. Trace element speciation in the environment

    International Nuclear Information System (INIS)

    The production of methylated heavy metal species in the ocean was reviewed and shown to be correlated with biological parameters demonstrating them to be of biogenic origin. Methods for the determination of the species were discussed. The potential for the use of isotopic spiking either in 'species specific' or 'non-species specific' formats was identified as a valuable tool in the struggle for accuracy, specificity and precision in speciation analysis. The value of using a size exclusion chromatographic method in conjunction with non-species specific spiking IDMS was highlighted with an example illustrating the molecular mass fractions associated with halogenated species from a humic sample. Additional recommendations that the Agency might wish to consider when evaluating its potential role as a service to Member States engaged in speciation activities are also given

  8. Investigating ecological speciation in non-model organisms

    DEFF Research Database (Denmark)

    Foote, Andrew David

    2012-01-01

    ecological variation underlie reproductive isolation between sympatric killer whale types. Perhaps ecological speciation has occurred, but it is hard to prove. We will probably face this outcome whenever we wish to address non-model organisms – species in which it is not easy to apply experimental approaches......Background: Studies of ecological speciation tend to focus on a few model biological systems. In contrast, few studies on non-model organisms have been able to infer ecological speciation as the underlying mechanism of evolutionary divergence. Questions: What are the pitfalls in studying ecological...... speciation in non-model organisms that lead to this bias? What alternative approaches might redress the balance? Organism: Genetically differentiated types of the killer whale (Orcinus orca) exhibiting differences in prey preference, habitat use, morphology, and behaviour. Methods: Review of the literature...

  9. Development and validation of a simple UV spectrophotometric method for the determination of levofloxacin both in bulk and marketed dosage formulations

    Institute of Scientific and Technical Information of China (English)

    Mahfuza Maleque; Md. Raquibul Hasan; Farhad Hossen; Sanjana Sail

    2012-01-01

    A rapid, specific and economic UV spectrophotometric method has been developed using a solvent composed of water:methanol:acetonitrile (9:0.5:0.5) to determine the levofloxacin content in bulk and pharmaceutical dosage formulations. At a pre-determined 2 of 292 nm, it was proved linear in the range of 1.0 12.0 μg/mL, and exhibited good correlation coefficient (R2=0.9998) and excellent mean recovery (99.0-100.07%). This method was successfully applied to the determination of levofloxacin content in five marketed brands from Bangladesh and the results were in good agreement with the label claims. The method was validated statistically and by recovery studies for linearity, precision, repeatability, and reproducibility. The obtained results proved that the method can be employed for the routine analysis of levofloxacin in bulks as well as in the commercial formulations.

  10. Silver-nanoparticle based bactericidal coating for poly(glycolide-co-lactide) suture threads obtained by the method of laser ablation of bulk targets in alcohol solutions

    Science.gov (United States)

    Babkina, O. V.; Svetlichnyi, V. A.; Lapin, I. N.; Novikov, V. T.; Nemoikina, A. L.

    2013-09-01

    A laser ablation method is suggested to synthesize a dispersion of silver nanoparticles to create a bactericidal coating of biodegradable suture material from poly(glycolide-co-lactide) using a bulk target immersed in a liquid. The laser ablation method with nanosecond excitation by a Nd:YAG laser (1064 nm, 7 ns) is used to obtain silver nanoparticles with mean diameter of 27 nm in ethanol. Nanoparticle concentrations up to 12 mass% were obtained on the polymer surfaces by multiple impregnation.

  11. Bulk meltwater flow and liquid water content of snowpacks mapped using the electrical self-potential (SP) method

    Science.gov (United States)

    Thompson, Sarah S.; Kulessa, Bernd; Essery, Richard L. H.; Lüthi, Martin P.

    2016-02-01

    Our ability to measure, quantify and assimilate hydrological properties and processes of snow in operational models is disproportionally poor compared to the significance of seasonal snowmelt as a global water resource and major risk factor in flood and avalanche forecasting. We show here that strong electrical self-potential fields are generated in melting in situ snowpacks at Rhone Glacier and Jungfraujoch Glacier, Switzerland. In agreement with theory, the diurnal evolution of self-potential magnitudes ( ˜ 60-250 mV) relates to those of bulk meltwater fluxes (0-1.2 × 10-6 m3 s-1) principally through the permeability and the content, electrical conductivity and pH of liquid water. Previous work revealed that when fresh snow melts, ions are eluted in sequence and electrical conductivity, pH and self-potential data change diagnostically. Our snowpacks had experienced earlier stages of melt, and complementary snow pit measurements revealed that electrical conductivity ( ˜ 1-5 × 10-6 S m-1) and pH ( ˜ 6.5-6.7) as well as permeabilities (respectively ˜ 9.7 × 10-5 and ˜ 4.3 × 10-5 m2 at Rhone Glacier and Jungfraujoch Glacier) were invariant. This implies, first, that preferential elution of ions was complete and, second, that our self-potential measurements reflect daily changes in liquid water contents. These were calculated to increase within the pendular regime from ˜ 1 to 5 and ˜ 3 to 5.5 % respectively at Rhone Glacier and Jungfraujoch Glacier, as confirmed by ground truth measurements. We conclude that the electrical self-potential method is a promising snow and firn hydrology sensor owing to its suitability for (1) sensing lateral and vertical liquid water flows directly and minimally invasively, (2) complementing established observational programs through multidimensional spatial mapping of meltwater fluxes or liquid water content and (3) monitoring autonomously at a low cost. Future work should focus on the development of self-potential sensor

  12. Application of Hyphenated Techniques in Speciation Analysis of Arsenic, Antimony, and Thallium

    OpenAIRE

    Rajmund Michalski; Sebastian Szopa; Magdalena Jabłońska; Aleksandra Łyko

    2012-01-01

    Due to the fact that metals and metalloids have a strong impact on the environment, the methods of their determination and speciation have received special attention in recent years. Arsenic, antimony, and thallium are important examples of such toxic elements. Their speciation is especially important in the environmental and biomedical fields because of their toxicity, bioavailability, and reactivity. Recently, speciation analytics has been playing a unique role in the studies of biogeochemi...

  13. A Method for Determining Bulk Density, Material Density, and Porosity of Melter Feed During Nuclear Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hilliard, Zachary J.; Hrma, Pavel R.

    2016-01-31

    Abstract Glass making efficiency largely depends on heat transfer to reacting glass batch (melter feed), which in turn is influenced by the bulk density (ρb) and porosity (Φ) as functions of temperature (T). Neither b(T) nor Φ(T) functions are readily accessible to direct measurement, but they can be determined based on monitoring the profile area of heated glass batch pellets and material density of batches quenched at various stages of conversion via pycnometry. For the determination of Φb, the bulk volume must be calculated as a function of temperature. This is done via a program constructed in MATLAB which takes an image of a pellet profile at a given temperature and calculates the volume of said pellet. The quenched density measured by pycnometry must be converted to the density at heat treatment temperature. This is done by taking into account the volume change due to thermal expansion/contraction.

  14. Preparation of a bulk Fe83B17 soft magnetic alloy by undercooling and copper-mold casting methods

    International Nuclear Information System (INIS)

    Bulk Fe83B17 eutectic alloy rods with diameters up to 3 mm were prepared by undercooling solidification combined with Cu-mold casting. The results showed that the rapid solidification led to an increase in the nucleation rate, an inhibition of the grain growth and a competition between a stable Fe2B phase and a metastable Fe3B phase. Then, pure nano-lamellar eutectic microstructures and the metastable Fe3B phase were successfully obtained in as-solidified alloys, which resulted in improved soft magnetic properties. - Highlights: • Pure nano-lamellar eutectic structure was directly formed in the bulk Fe-B alloys. • The metastable Fe3B phase was directly formed in the bulk Fe-B alloys. • Undercooling solidification combined with Cu-mold casting was applied. • The information on bcc Fe, Fe2B and Fe3B-magnetism relationship was provided. • Nano-lamellar eutectic structures enhance the soft magnetic properties

  15. DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF GLIPIZIDE AND METFORMIN IN BULK DRUGS AND TABLET DOSAGE FORM

    OpenAIRE

    D.Triveni; G.V.S Kumar; S B Puranik; N.Sateesh Kumar; K.A.Sridhar

    2012-01-01

    The present work describes development and validation of simple, precise and accurate reversed-phase liquid chromatographic method for simultaneous estimation of glipizide and metformin hydrochloride in both bulk drugs and pharmaceutical dosage forms. The chromatographic separation was achieved on (Enable, symmetry C18, 250mm x 4.6mm, 5μ) analytical column. A mobile phase consisting mixture of potassium dihydrogen phosphate (0.2M, pH 5.8 adjusted with dilute sodium hydroxide) and acetonitrile...

  16. Observation of persistent photoconductivity in bulk Gallium Arsenide and Gallium Phosphide samples at cryogenic temperatures using the Whispering Gallery mode method

    CERN Document Server

    Hartnett, J G; Floch, J -M Le; Krupka, J; Tobar, M E; Cros, D

    2009-01-01

    Whispering Gallery modes in bulk cylindrical Gallium Arsenide and Gallium Phosphide samples have been examined both in darkness and under white light at cryogenics temperatures < 50 K. In both cases persistent photoconductivity was observed after initially exposing semiconductors to white light from a halogen lamp. Photoconductance decay time constants for GaP and GaAs were determined to be 0.900 +/- 0.081 ns and 1.098 +/- 0.063 ns, respectively, using this method.

  17. Development and validation of a headspace gas chromatographic method for the determination of residual solvents in arterolane (RBx11160 maleate bulk drug

    Directory of Open Access Journals (Sweden)

    Abhishek Gupta

    2010-01-01

    Full Text Available Objective : Arterolane maleate is an antimalarial drug currently under Phase III clinical evaluation, and presents a simple, economical and scalable synthesis, and does not suffer from safety problems. Arterolane maleate is more active than artemisinin; and is cheap to produce. It has a longer lifetime in the plasma, so it stays active longer in the body. To provide quality control over the manufacture of any API, it is essential to develop highly selective analytical methods. In the current article we are reporting the development and validation of a rapid and specific Head space gas chromatographic (HSGC method for the determination of organic volatile impurities (residual solvents in Arterolane Maleate bulk drug. Materials and Methods : The method development and its validation were performed on Perkin Elmer′s gas chromatographic system equipped with Flame Ionization detector and head space analyzer. The method involved a thermal gradient elution of ten residual solvents present in arterolane maleate salt in RTx-624, 30 m Χ 0.32 mm, 1.8 μ column using nitrogen gas as a carrier. The flow rate was 0.5 ml/min and flame ionization detector (FID was used. Results : During method validation, parameters such as precision, linearity, accuracy, limit of quantification and detection and specificity were evaluated, which remained within acceptable limits. Conclusions : The method has been successfully applied for the quantification of the amount of residual solvents present in arterolane maleate bulk drug.The method presents a simple and reliable solution for the routine quantitative analysis of residual solvents in Arterolane maleate bulk drug.

  18. Superconducting and mechanical properties of the bulk Bi(pb)SCCO system prepared via solid state and ammonium nitrate precipitation methods

    Energy Technology Data Exchange (ETDEWEB)

    Safran, S., E-mail: safran@science.ankara.edu.tr [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Kılıçarslan, E.; Ozturk, H. [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Alp, M. [Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Akdogan, M. [Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Abant İzzet Baysal University, Department of Physics, Bolu (Turkey); Asikuzun, E.; Ozturk, O. [Kastamonu University, Department of Physics, Kastamonu (Turkey); Kastamonu University, Research and Application Center, Kastamonu (Turkey); Kılıç, A. [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey)

    2015-09-01

    We have investigated the effect of preparation method on superconducting and mechanical properties of Bi(Pb)-2223 bulk samples using Bi{sub 1.85}Pb{sub 0.35}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10±y} stoichiometry. Solid-state reaction and ammonium nitrate precipitation methods have been used for fabrication of the bulk samples. In addition, the effect of annealing time on BSCCO samples have been studied. Structural, electrical, magnetic and microhardness analyses of samples are performed by the X-ray powder diffraction (XRD), the Scanning Electron Microscopy (SEM), DC resistivity, AC susceptibility and Vickers microhardness test. The critical transition temperature, phase purity, surface morphology and crystallinity of the prepared bulk samples are compared with each other. Elasticity (E), brittleness (B{sub i}), fracture toughness (K{sub IC}) and yield strength (Y) values are also determined according to annealing time, applied load and production parameters of materials.

  19. Speciation needs in relation with environmental and biological purposes

    International Nuclear Information System (INIS)

    Radionuclides can occur in the environment either through chronic releases of nuclear facilities, or due to incidents or accidents. In order to study their behaviour in the environment (migration, retention, transfer, and in human organisms (metabolism, retention, excretion), it is of prime importance to know their solution chemistry, and more particularly thermodynamic constants, which will allow to determine their speciation. In fact, speciation governs the migration, the bioavailability and the toxicity of elements. Moreover, this knowledge is also of great interest for decorporation or decontamination purposes. In this framework, a CEA working group on speciation has been created in order to share data both on thermodynamic constants and on speciation analytical methods, interesting chemists, environmentalists and biologists. It has been focused, in a first time, on actinides, namely Th, U, Pu, Am, Np, taking into account their most important oxidation states occurring in environmental or biological environments: Th(IV), U(IV, VI), Pu(III, IV, VI), Am(III), Np(IV, V). A particular attention was devoted to the choice of ligands (inorganic and organic) for being the most representative of environmental and biological media. The thermodynamic database used is BASSIST for Base Applied to Speciation in Solution and at Interfaces and Solubility (developed by CEA), in interaction with the code JCHESS. Different examples will be then presented on the selection of data (thermodynamic constants, ligands of interest) through benchmark exercises (case of U(VI), Am(III), Pu(IV)) which will show the lacks or weakness of knowledge. Speciation diagrams will support these discussions. Moreover, analytical methods to determine thermodynamic constants or direct speciation will also be presented and discussed. (author)

  20. Molybdenum Speciation and its Impact on Catalytic Activity during Methane Dehydroaromatization in Zeolite ZSM-5 as Revealed by Operando X-Ray Methods.

    Science.gov (United States)

    Lezcano-González, Inés; Oord, Ramon; Rovezzi, Mauro; Glatzel, Pieter; Botchway, Stanley W; Weckhuysen, Bert M; Beale, Andrew M

    2016-04-18

    Combined high-resolution fluorescence detection X-ray absorption near-edge spectroscopy, X-ray diffraction, and X-ray emission spectroscopy have been employed under operando conditions to obtain detailed new insight into the nature of the Mo species on zeolite ZSM-5 during methane dehydroaromatization. The results show that isolated Mo-oxo species present after calcination are converted by CH4 into metastable MoCx Oy species, which are primarily responsible for C2 Hx /C3 Hx formation. Further carburization leads to MoC3 clusters, whose presence coincides with benzene formation. Both sintering of MoC3 and accumulation of large hydrocarbons on the external surface, evidenced by fluorescence-lifetime imaging microscopy, are principally responsible for the decrease in catalytic performance. These results show the importance of controlling Mo speciation to achieve the desired product formation, which has important implications for realizing the impact of CH4 as a source for platform chemicals. PMID:26990500

  1. Selenium Speciation and Management in Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Searcy, K; Richardson, M; Blythe, G; Wallschlaeger, D; Chu, P; Dene, C

    2012-02-29

    rapidly than it sorbs to ferric solids. Though it was not possible to demonstrate a decrease in selenium concentrations to levels below the project'ale testing were evident at the pilot scale. Specifically, reducing oxidation air rate and ORP tends to either retain selenium as selenite in the liquor or shift selenium phase partitioning to the solid phase. Oxidation air flow rate control may be one option for managing selenium behavior in FGD scrubbers. Units that cycle load widely may find it more difficult to impact ORP conditions with oxidation air flow rate control alone. Because decreasing oxidation air rates to the reaction tank showed that all new selenium reported to the solids, the addition of ferric chloride to the pilot scrubber could not show further improvements in selenium behavior. Ferric chloride addition did shift mercury to the slurry solids, specifically to the fine particles. Several competing pathways may govern the reporting of selenium to the slurry solids: co-precipitation with gypsum into the bulk solids and sorption or co-precipitation with iron into the fine particles. Simultaneous measurement of selenium and mercury behavior suggests a holistic management strategy is best to optimize the fate of both of these elements in FGD waters. Work conducted under this project evaluated sample handling and analytical methods for selenium speciation in FGD waters. Three analytical techniques and several preservation methods were employed. Measurements of selenium speciation over time indicated that for accurate selenium speciation, it is best to conduct measurements on unpreserved, filtered samples as soon after sampling as possible. The capital and operating costs for two selenium management strategies were considered: ferric chloride addition and oxidation air flow rate control. For ferric chloride addition, as might be expected the reagent makeup costs dominate the overall costs, and range from 0.22 to 0.29 mills/kWh. For oxidation air flow rate

  2. Flowability of bulk solids used in shale fracturing grouts as determined by the Jenike and Johanson method

    International Nuclear Information System (INIS)

    Smooth operation of the shale fracturing facility at Oak Ridge National Laboratory requires that an even, uninterrupted flow of dry solids be delivered to a mixer at a rate of approximately 1200 lb/min. Some operational difficulties have been experienced with the dry solids system at the existing facility. Occasionally the solids flow from a bin was difficult to initiate or was irregular, particularly when the storage bin was nearly empty. A new shale fracturing facility is now being designed with a solids handling system that will eliminate the current problems. This report describes the tests made to obtain the necessary information about bulk-flow properties of the dry solids that are required for the facility modifications. Flow properties of fly ash, attapulgite, pottery clay, and a blended solids mix were determined in a Jenike and Johanson Flowfactor Tester. Tests with this unit involve the consolidation of a solid at a given pressure and the measurement of the force required to create a shear plane. The procedure is repeated several times at different consolidating pressures to determine a locus of points that can be displayed graphically. Results indicate that a bottom-hopper opening of about 4 ft will be required on the new, bulk storage bins if mass flow is to be achieved. It was also found that the existing bins are quite unsuitable for either their present function or their proposed function. Since these bins have served moderately well for 14 years, the effect of aeration is obviously major; these tests indicate only an upper limit to the size of the hopper opening that will be required. Pottery clay and attapulgite were found to have flow characteristics considerably inferior to blended solids. It is known, however, that attapulgite clay will flow from the existing bins, and modification of the bin bottoms to enlarge the openings does not appear to be justified

  3. Polymerisationseigenschaften von Bulk-Fill Kompositen

    OpenAIRE

    Maier, Eva

    2015-01-01

    Hintergrund und Ziele: Untersuchung der Polymerisationseigenschaften von Bulk-Fill Kompositen bzgl. Konversionsrate (degree of conversion = DC), Vickers-Härte (HV), Polymerisationsschrumpfungsstress (PSS) und Polymerisationsvolumenschrumpfung (PVS) im Vergleich zu konventionellen Kompositen. Material und Methode: Untersucht wurden die Bulk-Fill Komposite Filtek Bulk Fill Flowable (FBF, 3M ESPE, Seefeld), Surefil Smart Dentin Replacement (SDR, Dentsply, Konstanz), Tetric EvoCeram Bulk Fill...

  4. DEVELOPMENT AND VALIDATION OF STABILITY-INDICATING TLC-DENSITOMETRY METHOD FOR THE SIMULTANEOUS DETERMINATION OF EPERISONE HYDROCHLORIDE AND PARACETAMOL IN BULK AND TABLET DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    Pritam S. Jain

    2013-08-01

    Full Text Available A rapid and reproducible stability indicating TLC-densitometric method was developed for the determination of eperisone hydrochloride and paracetamol in presence of their degraded products in bulk drugs and pharmaceutical formulations. Uniform degradation conditions were maintained by refluxing reaction mixtures for 8 h at 60°C including acidic, alkaline hydrolysis. Oxidation at room temperature, photochemical and dry heating degradation studies were also carried out. A sensitive and robust stability indicating TLC-densitometric method for simultaneous quantification of eperisone hydrochloride and paracetamol in bulk drugs and pharmaceutical formulations has been developed and validated. Separation was done on TLC aluminum sheets, pre-coated with silica gel 60F-254 using ethyl acetate: toluene: methanol (2:2:1 v/v/v. Spots at Rf 0.42 ± 0.04 and Rf 0.60 ± 0.02 were recognized as paracetamol and eperisone hydrochloride, respectively. Densitometric analysis of chromatoplates was carried out in absorbance mode at isobastic point 260 nm. The developed method was optimized and validated as per ICH guidelines. Method was found linear over the concentration range of 100-350 ng / spot for eperisone hydrochloride and 600-2100 ng / spot for paracetamol with the correlation coefficient (r2 of 0.999 and 0.999 for eperisone hydrochloride and paracetamol, respectively. The developed TLC method can be applied for routine analysis of eperisone hydrochloride and paracetamol in presence of their degraded products in their combined pharmaceutical formulations.

  5. Speciation of triphenyltin compounds using Moessbauer spectroscopy. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Eng, G.

    1993-11-01

    Organotin compounds have been used widely as the active agent in antifouling marine paints. Organotin compounds, i.e., tributyltin compounds (TBTs) and triphenyltin compounds (TPTs) have been found to be effective in preventing the unwanted attachment and development of aquatic organisms such as barnacles, sea grass and hydroids on ships, hulls and underwater surfaces. However, these organotin compounds have been found to be toxic to non-targeted marine species as well. While speciation of tributyltins in environmental water systems has received much attention in the literature, little information concerning the speciation of triphenyltins is found. Therefore, it would be important to study the fate of TPTs in the aquatic environment, particularly in sediments, both oxic and anoxic, in order to obtain speciation data. Since marine estuaries consist of areas with varying salinity and pH, it is important to investigate the speciation of these compounds under varying salinity conditions. In addition, evaluation of the speciation of these compounds as a function of pH would give an insight into how these compounds might interact with sediments in waters where industrial chemical run-offs can affect the pH of the estuarine environment. Finally, since organotins are present in both salt and fresh water environments, the speciation of the organotins in seawater and distilled water should also be studied. Moessbauer spectroscopy would provide a preferred method to study the speciation of triphenyltins as they leach from marine paints into the aquatic environment. Compounds used in this study are those triphenyltin compounds that are commonly incorporated into marine paints such as triphenyltin fluoride (TPTF), triphenyltin acetate (TPTOAc), triphenyltin chloride (TPTCl) and triphenyltin hydroxide (TPTOH).

  6. Effect of reinforcement surface functionalization on the mechanical properties of nacre-like bulk lamellar composites processed by a hybrid conventional method

    International Nuclear Information System (INIS)

    Alumina platelet reinforced epoxy matrix composites with an architecture resembling to natural nacre were fabricated by a hybrid conventional method called Hot-press Assisted Slip Casting process (HASC). Correlation between processing parameters, platelet content, platelet orientation and mechanical property enhancement of the fabricated composites was examined. In order to investigate the effect of interfacial compatibility and bonding on the mechanical properties of the fabricated inorganic–organic composites, platelet surfaces were modified with both epoxy- and amino-functional silanes. As received and functionalized platelet surfaces were studied by X-Ray Photoelectron Spectroscopy (XPS) to confirm the success of surface modification. Fabricated bio-inspired bulk lamellar composite materials were characterized in terms of their microstructural architecture and mechanical properties. The results obtained indicated that HASC processed composites exhibit enhanced flexural strength, stiffness and hardness, as compared to neat epoxy and composites fabricated by simple mixing, as a result of their nacre-like architecture with well aligned platelets. It has been also observed that functionalization by both type of silanes improves interfacial adhesion between platelets and epoxy matrix resulting in further enhancement of the mechanical properties of bulk lamellar composites fabricated by HASC. - Highlights: ► Bulk lamellar inorganic–organic composites were fabricated by HASC process. ► Effect of platelet content and orientation on mechanical properties was examined. ► Interfacial adhesion was improved by surface treatment of platelets with silanes. ► Impact of interfacial bonding on mechanical properties of composites was revealed

  7. Simultaneous multielement speciation analysis in food using neutron activation

    International Nuclear Information System (INIS)

    Complete text of publication follows. We develop various forms of neutron activation analysis (NAA) methods for the simultaneous determination of multielement concentrations in biological and environmental materials. Although NAA has traditionally been applied to measuring the total concentrations of elements, the scope of NAA can be further extended in conjunction with chemical separations prior to irradiations to determine the species of an element. This technique is then called simultaneous speciation NAA (SSNAA). Almost all speciation techniques consist of two steps. The first step involves the separation of species from the sample followed by the second step of element-specific detection. A number of characteristic features of NAA, which other techniques normally do not possess, can be advantageously exploited in SSNAA. For example, SSNAA can be used for: (i) simultaneous multielement speciation with high specificity, (ii) speciation of elements which are not chemically similar such as Cd, Mn and Se, (iii) speciation of elements such as Cl, Br and I which are rather difficult to determine by most other techniques, etc. The SSNAA technique has some unique quality assurance features. We have developed SNAA methods for assaying various arsenic species in water and in foods of marine origin, and then SSNAA to include simultaneous speciation of As, Sb and Se. We have developed SSNAA methods for the characterization of organohalogen species in fish and milk samples. We have also developed SSNAA methods employing biochemical techniques for the simultaneous separation, preconcentration and characterization of metalloproteins and protein-bound trace element species of As, Br, Cd, Cu, Mn, Se and Zn. An overview of the SSNAA methods being developed in our laboratory will be presented.

  8. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel;

    2015-01-01

    restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and...... three low-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low...

  9. Cancer: beyond speciation.

    Science.gov (United States)

    Vincent, Mark D

    2011-01-01

    A good account of the nature of cancer should provide not only a description of its consistent features, but also how they arise, how they are maintained, why conventional chemotherapy succeeds, and fails, and where to look for better targets. Cancer was once regarded as enigmatic and inexplicable; more recently, the "mutation theory," based on random alterations in a relatively small set of proto-oncogenes and tumor suppressor genes, has enjoyed widespread acceptance. The "mutation theory," however, is noticeable for its failure to explain the basis of differential chemosensitivity, for providing a paucity of targets, especially druggable ones, and for justifying the development of targeted therapies with, in general, disappointingly abbreviated clinical benefit. Furthermore, this theory has mistakenly predicted a widespread commonality of consistent genetic abnormalities across the range of cancers, whereas the opposite, that is, roiling macrogenomic instability, is generally the rule. In contrast, concerning what actually is consistent, that is, the suite of metabolic derangements common to virtually all, especially aggressive, cancers, the "Mutation Theory" has nothing to say. Other hypotheses merit serious consideration "aneuploidy theories" posit whole-genome instability and imbalance as causally responsible for the propagation of the tumor. Another approach, that is, "derepression atavism," suggests cancer results from the release of an ancient survival program, characterized by the emergence of remarkably primitive features such as unicellularity, fermentation, and immortality; existential goals are served by heuristic genomic instability coupled with host-to-tumor biomass interconversion, mediated by the Warburg effect, a major component of the program. Carcinogenesis is here seen as a process of de-speciation; however, genomic nonrestabilization raises issues as to where on the tree of life cancers belong, as a genuinely alternative modus vivendi

  10. Investigation of the structure and properties of Fe-Co-B-Si-Nb bulk amorphous alloy obtained by pressure die casting method

    Directory of Open Access Journals (Sweden)

    W. Pilarczyk

    2012-12-01

    Full Text Available Purpose: The main aim of this paper is investigation of the microstructure and thermal properties of selected Fe-Co-B-Si-Nb bulk amorphous alloy.Design/methodology/approach: The studies were performed on Fe-Co-B-Si-Nb alloy in form of rods with diameter of ø=1.5 and ø=2 mm. Master alloy ingot with compositions of Fe37.44Co34.56B19.2Si4.8Nb4 was prepared by induction melting of pure Fe, Co, B, Si and Nb elements in argon atmosphere. The structure analysis of the studied materials in as-cast state was carried out using X-ray diffraction (XRD. The thermal properties: glass transition temperature (Tg, onset crystallization temperature (Tx and peak crystallization temperature (Tp of the as-cast alloys were examined by differential scanning calorimetry (DSC method. The microscopic observation of the fracture morphology of studied amorphous materials in rods form with different diameter was carried out by means of scanning electron microscope (SEM, within different magnification.Findings: The Fe-based bulk metallic glasses in form of rod were successfully produced by die pressure casting method. The investigation revealed that the studied rods are amorphous. These materials exhibit good glassforming ability. These tested rods with diameter of 1.5 and 2 mm exhibit similar characteristic temperatures (Tg, Tx, Tp. The exothermic peaks describing crystallization process of studied bulk metallic glasses are observed Morphology of cross section rods is changing having contact with copper mould during casting from smooth fracture inside rod to fine narrow dense veins pattern near to rod surface. These rods have smooth surface and metallic luster. The presented fractures are characteristic for metallic glasses.Practical implications: The success of production of studied Fe-based bulk metallic glasses is important for future practical application of those materials as elements of magnetic circuits, sensors and precise current transformers

  11. Quantitative comparison of in house irma/ria methods using reagents supplied in bulk with assays based on commercial kits

    International Nuclear Information System (INIS)

    Due to high cost of commercial kit assays, local trials were started to establish low cost immunoassay techniques at MINAR, Multan. First available alternate of commercial kits was the use of matched reagents supplied in bulk by NETRIA through INMOL, Lahore under IAEA assistance. As quality is crucial in RIA estimations this laboratory collected passive quality control data of 50, 51 and 52 in-house assay batches of T3,T4 and TSH to compare with the same number of last Amerlex RIAs(successive lots). A qualitative comparison based on computerized data analysis shows linear correlation between the results of two assay systems with low and acceptable precision in T3 and T4 assays. In TSH assays both systems show high imprecision although Amerlex RIA system is relatively more precise than in-house TSH- IRMA. T3 and T4 assays in both the systems show wide working ranges covering all clinical regions. In TSH, working ranges of both the techniques do not cover all clinical regions. In-house TSH assay excludes below 5.5 mulU/ml, whereas Amerlex excludes levels below 4.5 mulL/ml. This may reduce the clinical efficacy of these tests. Amerlex-M T3 and T4 assays show high negative drift with relatively less between variation, whereas in-house assays show low positive drift with high between batch variation. (author)

  12. Application of a Validated Stability-Indicating LC Method for the Simultaneous Estimation of Tapentadol and Its Process-Related Impurities in Bulk and Its Dosage Form

    OpenAIRE

    Singaram Kathirvel; Suggala Venkata Satyanarayana; Garikapati Devalarao

    2013-01-01

    Described is a first reported, simple, rapid, selective, and isocratic stability-indicating RP-LC method for the quantitative determination of tapentadol and its related substances in bulk samples and pharmaceutical dosage forms in the presence of its two process-related impurities. Chromatographic separation was achieved on the reversed phase, Enable column (C18 (5-μm, 250 × 4.6 mm, i.d.)) at ambient temperature using a mobile phase consisting of 0.02 M potassium dihydrogen orthophosphate (a...

  13. Effect of cooking method on the fatty acid content of reduced-fat and PUFA-enriched pork patties formulated with a konjac-based oil bulking system.

    Science.gov (United States)

    Salcedo-Sandoval, Lorena; Cofrades, Susana; Ruiz-Capillas, Claudia; Jiménez-Colmenero, Francisco

    2014-12-01

    The effect of cooking methods (electric grilling and pan-frying in olive oil) on the composition of reduced-fat and reduced-fat/PUFA enriched pork patties was studied. Fat reduction was performed by replacing pork backfat (38% and 100%) with konjac gel and PUFA-enrichment by replacing pork backfat (49%) with a konjac-based oil bulking system stabilizing a healthier oil combination (olive, linseed and fish oils). Cooking losses (13%-27%) were affected (pKonjac materials were successfully used to produce pork patties with a better lipid composition. PMID:25150632

  14. DEVELOPMENT AND VALIDATION OF A RP- HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF OMEPRAZOLE AND CINITAPRIDE IN BULK AND CAPSULE DOSAGE FORM

    OpenAIRE

    Nagarajan, G.; Nagesh, P.; Ramana, B.V.; N. Ratna Prasanna; C.Triveni

    2013-01-01

    A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed and validated for simultaneous determination of Omeprazole and Cinitapride in bulk and Capsule dosage form. Chromatographic analysis was performed on a Symmetry C8 column (150x 4.5 mm, 5μm) column ambient temperature with a mixture of mixed phosphate buffer and Acetonitrile in the ratio 50:50 (mixed phosphate buffer preparation; 1.625 gm of potassium Dihydrogen phosphate and 0.3 gm of Di potass...

  15. METHOD DEVELOPMENT AND VALIDATION OF RP- HPLC IN THE APPLICATION OF IN-VITRO DISSOLUTION STUDY OF EMTRICITABINE IN BULK DRUG AND TABLET FORMULATION

    Directory of Open Access Journals (Sweden)

    Rajpoot Brajendra singh

    2012-02-01

    Full Text Available A new RP-HPLC method was developed for the determination of Emtricitabine in the bulk drug and tablet dosage forms and it was applied for the in vitro drug dissolution studies. Isocratic elution mode with a mixture of methanol and water in the ratio of (89:11 was selected as the mobile phase with a C18 column (250 x 4.6mm, 5µ for separation. This mixture was found to be appropriate allowing good elution for the Emtricitabine at retention time 2.72 minute at flow rate of 1 ml/min and detection wavelength at 272nm. The linearity was found in the concentration range of Emtricitabine 5-100 µ g/ml. The liquid chromatography method was extensively validated for linearity, range, accuracy, precision (intermediate precision, repeatability and specificity. All these analytical validation parameters were observed and the %RSD was determined which indicates the useful of RP-HPLC method for determination of Emtricitabine in the bulk drug & tablets dosage form.

  16. Development and Validation of RP-HPLC Method for the Simultaneous Estimation of Telmisartan and Hydrochlorothiazide in Bulk and Pharmaceutical Dosage Form

    Directory of Open Access Journals (Sweden)

    N. Mukuntha Kumar

    2014-10-01

    Full Text Available A simple, accurate, precise and rapid RP-HPLC method has been developed and validated for the simultaneous estimation of Telmisartan and Hydrochlorothiazide in bulk and fixed-dosage formulation. The separation was achieved on ACE 5 C18 (Length 150 mm × Diameter 4.6 mm Particle size 5 μm column with gradient flow. The mobile phase at a flow rate of 1.5 mL/min consisted of Water: Acetonitrile: Orthophospharic acid (95:5:1 Mobile Phase A and Water: Acetonitrile: Orthophospharic acid (5:95:1 Mobile Phase B (Gradient ratio. The UV detection was carried out at 280 nm. The retention time of Hydrochlorothiazide and Telmisartan was found to be 4.19 and 9.12 min. respectively. The method has been validated for Specificity, Linearity, Accuracy, Precision and Robustness. The calibration curve for Telmisartan and Hydrochlorothiazide were linear from the range of 160.1-480.4 μg/mL and 25.2 - 75.7 μg/mL respectively. The mean recoveries obtained for Telmisartan and Hydrochlorothiazide were 100.1% and 99.8% respectively. The developed method was found to be Specific, accurate, Precise, Robust and rapid for the simultaneous estimation of Telmisartan and Hydrochlorothiazide in bulk Pharmaceutical Dosage Form.

  17. A NOVEL METHOD FOR QUANTITATIVE DETERMINATION OF ACECLOFENAC IN BULK DRUG AND TABLETS USING SODIUM SALICYLATE AS A HYDROTROPIC SOLUBILIZING AGENT

    Directory of Open Access Journals (Sweden)

    Shruti Moondra

    2010-03-01

    Full Text Available In titrimetric analysis costlier organic solvents are more often employed tosolubilize the poorly water-soluble drugs. Volatility and pollution are drawbacks of suchsolvents. Various techniques are employed to enhance the aqueous solubility of poorlywater-soluble drugs. Hydrotropic solubilization phenomenon has been widely used toenhance the aqueous solubility of large number of poorly water-soluble drugs. Aqueoussolubility of aceclofenac bulk drug [a poorly water-soluble NSAID] was enhanced to agreat extent i.e., 400 folds with 2.5 M sodium salicylate. The primary objective of thepresent investigation was to employ this hydrotropic solution to extract the drug from itsdosage forms, precluding the use of costlier organic solvents. The proposed method ofanalysis is new, simple, accurate, environmentally friendly and reproducible. Statisticaldata proved the accuracy, reproducibility and the precision of the proposed method. Theresults of titrimetric analysis by use of hydrotropy compared very well with the results ofPharmacopoeial method.

  18. Plutonium Speciation in Support of Oxidative-Leaching Demonstration Test

    Energy Technology Data Exchange (ETDEWEB)

    Sinkov, Sergey I.

    2007-10-31

    Bechtel National, Inc. (BNI) is evaluating the plutonium speciation in caustic solutions that reasonably represent the process streams from the oxidative-leaching demonstration test. Battelle—Pacific Northwest Division (PNWD) was contracted to develop a spectrophotometric method to measure plutonium speciation at submicromolar (< 10-6 M) concentrations in alkaline solutions in the presence of chromate and carbonate. Data obtained from the testing will be used to identify the oxidation state of Pu(IV), Pu(V), and Pu(VI) species, which potentially could exist in caustic leachates. Work was initially conducted under contract number 24590-101-TSA-W000-00004 satisfying the needs defined in Appendix C of the Research and Technology Plan TSS A-219 to evaluate the speciation of chromium, plutonium, and manganese before and after oxidative leaching. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) Operating Contract MOA: 24590-QL-HC9-WA49-00001.

  19. Neutral Models with Generalised Speciation

    NARCIS (Netherlands)

    Haegeman, Bart; Etienne, Rampal S.

    2009-01-01

    Hubbell's neutral theory claims that ecological patterns such as species abundance distributions can be explained by a stochastic model based on simple assumptions. One of these assumptions, the point mutation assumption, states that every individual has the same probability to speciate. Etienne et

  20. Thermodynamics and speciation: Carbonate complexation of Am(III) and speciation of actinides by pulsed laser spectroscopies

    International Nuclear Information System (INIS)

    The report includes the carbonate complexation of Am(III) and speciation of actinides by pulsed laser spectroscopies. Part A describes the carbonate complexation behaviour of Am3+ in aqueous solution under 1% CO2 partial pressure, investigated by solubility and spectroscopic experiments. The average constants determined by the two methods are: log Ksp (Am2(CO3)3)=-29.7 ± 0.6, log β1=6.3 ± 0.3 and log β2 = 9.7 ± 0.6. Part B presents speciation capabilities of three different pulsed laser spectroscopies: laser-induced photoacoustic spectroscopy (LPAS), time-resolved laser-induced fluorescence spectroscopy (TRLFS) and photoacoustic detection of light scattering (PALS). Examples for the speciation of Am(III) and Cm(III) in different aquatic media are presented. (orig.)

  1. DEVELOPMENT AND VALIDATION OF A RP- HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF OMEPRAZOLE AND CINITAPRIDE IN BULK AND CAPSULE DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    G. Nagarajan

    2013-02-01

    Full Text Available A simple reversed-phase high-performance liquid chromatographic (RP-HPLC method has been developed and validated for simultaneous determination of Omeprazole and Cinitapride in bulk and Capsule dosage form. Chromatographic analysis was performed on a Symmetry C8 column (150x 4.5 mm, 5μm column ambient temperature with a mixture of mixed phosphate buffer and Acetonitrile in the ratio 50:50 (mixed phosphate buffer preparation; 1.625 gm of potassium Dihydrogen phosphate and 0.3 gm of Di potassium hydrogen phosphate in 550 mL HPLC grade water, pH= 6.0 adjust with phosphoric acid as mobile phase, at a flow rate of 1.0 mL min-1. UV detection was performed at 287 nm. The method was validated for accuracy, precision, specificity, linearity and sensitivity. The retention times of Omeprazole and Cinitapride were 2.49 and 3.650 min, respectively. Calibration plots were linear over the concentration ranges 5–30 μg mL-1 and 0.75-4.5 μg mL-1 for Omeprazole and Cinitapride, respectively. The Limit of detection was 1.43570 and 0.086 µg mL-1 and the quantification limit was 4.35 µg mL-1 and 0.26 µg mL-1 for Omeprazole and Cinitapride, respectively. The accuracy of the proposed method was determined by recovery studies and found to be 98.62% to 100.37%. Commercial capsule formulation was successfully analyzed using the developed method and the proposed method is applicable to routine analysis of determination of Omeprazole and Cinitapride in bulk and capsule dosage form.

  2. Characterization of Heavy Metal Contents in the Bulk Atmospheric Aerosols Simultaneously Collected at Three Islands in Okinawa, Japan by X-ray fluorescence spectrometric method (XRF)

    Science.gov (United States)

    Oshiro, Y.; ITOH, A.; Azechi, S.; Somada, Y.; Handa, D.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

    2011-12-01

    We studied heavy metal contents of atmospheric aerosols using an X-ray fluorescence spectrometric method (XRF). The XRF method enables us to analyze heavy metal contents of bulk aerosols rapidly without any chemical pretreatments. We used an energy dispersive X-ray fluorescence spectrometer that is compact and portable. We prepared several different amounts of standard reference materials (NIES No.28) of Japanese National Institute of Environmental Studies on quartz filters for calibration curves. Then, we evaluated quantitative responses of XRF method by comparing with the metal contents determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after acid-digestion. Good linear relationships between X-ray intensity and amount of aerosol on filter were seen in the following 10 metals; Al, K, Ti, V, Fe, Ni, Rb, Ba, Pb and As. We then used XRF method to determine heavy metal contents in authentic atmospheric aerosols collected in Okinawa islands, Japan. Okinawa islands, consisting of many small islands, are situated east of Asian continent, and its location in Asian is well suited for studying long-range transport of air pollutants. Also, in Okinawa islands, maritime air mass prevails during summer, while Asian continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background clean air and can be compared with continental air mass which has been affected by anthropogenic activities such as industries and automobiles. Therefore, Okinawa region is suitable area for studying impacts of air pollutants from East Asia. We simultaneously collected bulk aerosol samples by using identical high-volume air samplers at 3 islands; Cape Hedo Atmospheric Aerosol Monitoring Station (CHAAMS, Okinawa island), Kume island (ca. 160 km south-west of CHAAMS), and Minami-Daitou island (ca. 320 km south-east of CHAAMS). We report and discuss spatial and temporal distribution of heavy metals

  3. RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR THE ESTIMATION OF MONTELUKAST SODIUM IN BULK AND PHARMACEUTICAL DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    B.V.V Ravi kumar

    2012-11-01

    Full Text Available A simple, selective, linear, precise and accurate RP-HPLC method was developed and validated for rapid assay of Montelukast Sodium in pharmaceutical dosage form. Isocratic elution at a flow rate of 1.2 mL min -1 was employed on a symmetry C18 column at ambient temperature. The mobile phase consisted of acetonitrile: phosphate buffer 65:35 (v/v. The UV detection wavelength was at 234 nm. Linearity was observed in concentration range of 1-100 μg/mL. The retention time for Montelukast Sodium was 4.2 min. The method was validated as per the ICH guidelines. The proposed method can be successfully applied for the estimation of Montelukast Sodium in pharmaceutical dosage forms.

  4. A NOVEL VALIDATED RP-HPLC METHOD FOR THE DETERMINATION OF ITOPRIDE HYDROCHLORIDE IN BULK AND PHARMACEUTICAL TABLET DOSAGE FORMS

    Directory of Open Access Journals (Sweden)

    P.Ravisankar

    2013-04-01

    Full Text Available A simple, specific, accurate, rapid, inexpensive isocratic Reversed Phase-High Performance Liquid Chromatography (RP-HPLC method was developed and validated for the quantitative determination of Itopride HCl in pharmaceutical tablet dosage forms. RP-HPLC method was developed by using Welchrom C18Column (4.6 X 250mm, 5µm, Shimadzu LC-20AT Prominence Liquid Chromatograph. The mobile phase composed of 10mM Phosphate buffer (pH-3.0, adjusted with triethylamine: acetonitrile (50:50v/v. The flow rate was set to 1.0 mL.min-1 with the responses measured at 235nm using Shimadzu SPD-20A Prominence UV-Vis detector. The retention time of Itopride HCl was found to be 2.650 min. Linearity was established for Itopride HCl in the range of 2-10 µg.mL-1 with correlation coefficient 0.9999. The validation of the developed method was carried out for specificity, linearity, precision, accuracy, robustness, limit of detection, limit of quantitation. The developed method can be used for routine quality control analysis of Itopride HCl in pharmaceutical tablet dosage form.

  5. A Validated New Gradient Stability-Indicating LC Method for the Analysis of Doripenem in Bulk and Injection Formulation

    Directory of Open Access Journals (Sweden)

    Singaram Kathirvel

    2013-01-01

    Full Text Available A sensitive, precise, specific, linear, and stability-indicating gradient HPLC method was developed for the estimation of doripenem in active pharmaceutical ingredient (API and in injectable preparations. Chromatographic separation was achieved on C18 stationary phase with a mobile phase gradient consisting of acetonitrile, methanol, and pH 5.2 phosphate buffer. The mobile phase flow rate was 0.8 mL/min, and the eluted compounds were monitored at 210 nm. The method is linear over the range of 0.335 to 76.129 µg/mL. The correlation coefficient was found to be 0.999. The numbers of theoretical plates and tailing factor for doripenem were 53021 and 0.9, respectively. Doripenem was subjected to the International Conference on Harmonization (ICH prescribed hydrolytic (acid, base, and neutral, oxidative, photolytic, and thermal stress conditions. Among all the above-mentioned conditions, the drug was found to be stable under photolytic degradation. Peak homogeneity data for doripenem in the chromatograms from the stressed samples obtained by use of the photodiode array detector demonstrated the specificity of the method for analysis of doripenem in presence of the degradation products. The performance of the method was validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, and robustness.

  6. SIMULTANEOUS ESTIMATION OF FEXOFENADINE HYDROCHLORIDE AND MONTELUKAST SODIUM IN BULK DRUG AND MARKETED FORMULATION BY RP-HPLC METHOD

    OpenAIRE

    Ravisankar M; Subasini Uthirapathy; Ananda Thangadurai; Jambulingam Munusamy; Kamalakannan Dhanapal

    2012-01-01

    A new simple and precise accurate RP-HPLC method has been developed and validated for simultaneous estimation of Montelukast Sodium and Fexofenadine in tablet formulations. The chromatographic separation was performed in Water symmetry C8 (150X4.6mm 5µm) and mobile phase 0.05 m potassium di hydrogen ortho phosphate: acetonitrile in the ratio of 35:65 and the pH – 6 adjusted by triethylamine.The flow rate was 1.0ml/min and the wavelength selected for the quantization was 226 nm. The retention ...

  7. Development and validation of UV-spectrophotometric methods for the determination of sumatriptan succinate in bulk and pharmaceutical dosage form and its degradation behavior under varied stress conditions

    Directory of Open Access Journals (Sweden)

    Kudige Nagaraj Prashanth

    2014-04-01

    Full Text Available The aim of the present work is to develop sensitive, simple, accurate, precise and cost effective UV-spectrophotometric methods for the determination of sumatriptan succinate (STS, an anti-migraine drug, in bulk and pharmaceutical dosage form; and also to monitor the degradation behavior of the drug under different ICH prescribed stress conditions. Two methods were developed using different solvents, 0.1 M HCl (method A and acetonitrile (method B. The calibration graphs are linear over the range of 0.2–6.0 μg ml−1 in both the methods with a correlation coefficient (r of 0.9999. The apparent molar absorptivity values are 7.59 × 104 and 7.81 × 104 l mol−1 cm−1, for method A and method B, respectively. The other optical characteristics such as Sandell’s sensitivity, limit of detection (LOD and limit of quantification (LOQ values are also reported. The accuracy and precision of the methods were evaluated based on intra-day and inter-day variations. The accuracy of the methods was further confirmed by standard addition procedure. The degradation behavior of the drug was studied by subjecting STS to an acid and alkaline hydrolysis, oxidative, thermal and UV degradation. This study indicated that STS was degraded in alkaline medium and in oxidative condition. The proposed methods were successfully applied to the determination of STS in tablets and the results obtained are comparable with the official method.

  8. Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

    International Nuclear Information System (INIS)

    Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL−1, and demonstrated good linearity of R2 from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL−1. Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified

  9. The speciation of dissolved elements in aquatic solution. Radium and actinides

    International Nuclear Information System (INIS)

    In the publication, the chemistry and speciation of radium, thorium, protactinium, uranium, neptunium, lutonium, americium and curium in ground-water environment is reviewed. Special attention is given to the transuranium elements, which have a central role in the repository of nuclear wastes. The most important methods used in the speciation of these elements is presented. The laser-induced methods, developed in the 1980's, are especially discussed. These have made it possible, e.g., to speciate the transuranium elements in their very low, actual repository ground-water concentrations (10-100 ng/l). (54 refs., 10 figs., 3 tabs.)

  10. Production of CeO2 Nanoparticles by Method of Laser Ablation of Bulk Metallic Cerium Targets in Liquid

    Science.gov (United States)

    Svetlichnyi, V. A.; Lapin, I. N.

    2016-03-01

    The method of pulsed laser ablation in liquid was used to synthesize dispersions of cerium oxide nanoparticles when subjecting a metallic cerium target in water and alcohol to basic frequency radiation of the nanosecond Nd:YAG laser (1064 nm, 7 ns, 20 Hz). Researchers have studied the effect of laser radiation parameters, duration of impact, and optical scheme of experiment on the ablation process. The average rate of nanoparticle production was 50 mg/h in water and 25 mg/h in alcohol. Researchers have studied the size characteristics and crystalline structure of the nanoparticles produced. The particles have bimodal size distribution with 6 nm and 25 nm maximums. The average crystallite size is 17-19 nm. The crystalline structure of nanoparticles, namely cubic cerium oxide (fluorite structure), space group Fm-3m, is confirmed by the X-ray diffraction data, as well as optical absorption spectra and Raman spectroscopy.

  11. Development and Validation of Stability-Indicating GC-FID Method for the Quantitation of Memantine Hydrochloride and Its Nonchromophoric Impurities in Bulk and Pharmaceutical Dosages

    Directory of Open Access Journals (Sweden)

    Sanjay A. Jadhav

    2012-01-01

    Full Text Available A stability-indicating method has been developed and validated for the quantitative determination of memantine hydrochloride and its nonchromophoric impurities in drug substance and drug product using gas chromatography coupled with flame ionization detector (GC-FID. The stability-indicating nature of the method has been proved by establishing peak purity and confirming the mass balance of all samples by subjecting them to stress conditions like hydrolysis, oxidation, photolysis, and thermal degradation studies. The chromatographic separation was performed on a fused silica capillary (HP-5, 30 meter, 0.32 mm and 0.25 μm film thickness column. The method validation results indicate that the method has acceptable specificity, accuracy, linearity, precision, robustness, and high sensitivity with detection limits and quantitation limits ranging from 0.001% to 0.01% and 0.004% to 0.03%, respectively. The effectiveness of the technique was demonstrated by analysis of different bulk sample of Memantine hydrochloride. The proposed GC-FID method was also found to be specific and selective for the analysis of commercial formulation samples.

  12. Rapid preparation method of bulk nanostructured Yb0.3Co4Sb12+y compounds and their improved thermoelectric performance

    International Nuclear Information System (INIS)

    A synthetic route was introduced to speed up the preparation of high performance nanostructured Yb0.3Co4Sb12+y (y=0.3 and 0.6) compounds. Compared with the samples prepared by a traditional method, the processing time is reduced from the typical 10 days to less than 40 h, the Yb filling fraction limit increases, and the resulting thermoelectric transport properties are improved significantly. As a consequence, the dimensionless figure of merit of our bulk nanostructured Yb0.3Co4Sb12.3 reaches 1.3 at 800 K. The enhanced thermoelectric performance coupled with the dramatically reduced processing time will be of considerable significance to the commercial-scale production of skutterudite-based thermoelectric materials

  13. SIMULTANEOUS ESTIMATION OF FEXOFENADINE HYDROCHLORIDE AND MONTELUKAST SODIUM IN BULK DRUG AND MARKETED FORMULATION BY RP-HPLC METHOD

    Directory of Open Access Journals (Sweden)

    Ravisankar M

    2012-04-01

    Full Text Available A new simple and precise accurate RP-HPLC method has been developed and validated for simultaneous estimation of Montelukast Sodium and Fexofenadine in tablet formulations. The chromatographic separation was performed in Water symmetry C8 (150X4.6mm 5µm and mobile phase 0.05 m potassium di hydrogen ortho phosphate: acetonitrile in the ratio of 35:65 and the pH – 6 adjusted by triethylamine.The flow rate was 1.0ml/min and the wavelength selected for the quantization was 226 nm. The retention time was found to be 2.127 min for Fexofenadine and 5.650 min for Montelukast sodium .The linearity were found to be in the range of 4.8 - 28.8 µg/ml and 0.4 – 2.4 µg/ml for Fexofenadine and Montelukast respectively with the correlation co efficient of 0.999.The mean recoveries for Fexofenadine and Montelukast were 99.85 % and 100.19 % respectively, and relative standard deviation was less than 2%. Precision were performed as per ICH guidelines with the result shows relative standard deviation not more than 2%.The assay value for Fexofenadine and Montelukast were found to be 100.55 % and 100.40 % respectively.

  14. Liquid chromatographic method for the simultaneous determination of captopril, piroxicam, and amlodipine in bulk drug, pharmaceutical formulation, and human serum by programming the detector.

    Science.gov (United States)

    Sultana, Najma; Arayne, M Saeed; Ali, Saeeda Nadir

    2013-10-01

    A highly sensitive LC method with UV detection has been developed for the simultaneous determination of coadministered drugs captopril, piroxicam, and amlodipine in bulk drug, pharmaceutical formulations, and human serum at the isosbestic point (235 nm) and at individual λmax (220, 255, and 238 nm, respectively) by programming the detector with time to match the individual analyte's chromophore, which enhanced the sensitivity with linear range. The assay involved an isocratic elution of analytes on a Bondapak C18 (10 μm, 25 × 0.46 cm) column at ambient temperature using a mobile phase of methanol/water 80:20 at pH 2.9 and a flow rate of 1.0 mL/min. Linearity was found to be 0.25-25, 0.10-6.0, and 0.20-13.0 μg/mL with correlation coefficient >0.998 and detection limits of 7.39, 3.90, and 9.38 ng/mL, respectively, whereas calibration curves for wavelength-programmed analysis were 0.10-6.0, 0.04-2.56, and 0.10-10.0 μg/mL with correlation coefficient >0.998 and detection limits of 5.79, 2.68, and 3.87 ng/mL, respectively. All the validated parameters were in the acceptable range. The recovery of drugs was 99.32-100.39 and 98.65-101.96% in pharmaceutical formulation and human serum, respectively, at the isosbestic point and at individual λmax . This method is applicable for the analysis of drugs in bulk drug, tablets, serum, and in clinical samples without interference of excipients or endogenous serum components. PMID:23897845

  15. Trace element speciation in man

    International Nuclear Information System (INIS)

    The toxicological properties associated with an element depend upon its chemical form since this will dictate the metabolic pathway that the compound follows in the body. The speciation of the element is determinant for its physiological behaviour in a living system. The complicated interactions of the different forms of trace elements in human metabolism were reviewed and the species present were categorised into seven groups. The complexity of the tasks involved in a study of trace element speciation in man was illustrated and many of the pitfalls were identified together with an example of the detective approach that must be followed to elucidate the intricacies of the associations between trace elements and biomolecular moieties

  16. Cationic speciation in nonaqueous media

    International Nuclear Information System (INIS)

    Electronic spectra of solutions of d transition elements in the superacids HF, H2SO4, HSO3F, and CF3SO3H and in chloroaluminate melts indicate that in acidic monaqueous media the elements are present as solvated cations, whereas in basic media the speciation is anionic, the same situation as in aqueous solutions. Further, in very highly acidic media, cations in very low oxidation states are stable (e.g., Ti2+), but these disproportionate on addition of base to the system. In this paper spectra, where available, of U, Np, and Pu in oxidation states III and IV in aqueous media, in protonic superacids, and in chloroaluminates are presented to postulate cationic speciation of these early actinides in highly acidic media

  17. Aspects of speciation in foodstuffs

    International Nuclear Information System (INIS)

    Food is the primary source of trace elements for humans and it is now generally accepted that the bioavailability of a given element and its behaviour in the body depends upon its chemical form. This point was illustrated with the example of arsenic speciation in fish in which bioaccumulation takes place in the marine food chain, however, the species of arsenic ingested by man when the fish is consumed are not toxic. It was pointed out that species information will be vital in deciding upon realistic average dietary requirements for trace elements, particularly because both deficiency or excess of an element can have detrimental consequences on an individual's health. Two examples of speciation studies with food (Cd and Se) were presented and the importance of the use of label technology which will allow studies of target analytes at physiological levels, was stressed

  18. Chiral speciation of selenoamino acids in biological samples.

    Science.gov (United States)

    Chen, Beibei; He, Man; Zhong, Cheng; Hu, Bin

    2014-10-10

    In this paper, the "state of the art" of chiral speciation of selenoamino acids (SeAAs) in biological samples is critically reviewed. The significance and the features of such studies are highlighted. A special focus lies on chiral speciation of SeAAs by hyphenation techniques in which a chiral separation method (such as gas chromatography (GC), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE)) is on-line coupled with an elemental specific detector, especially inductively coupled plasma mass spectrometry (ICP-MS). The advances in the development and application of hyphenation techniques in chiral speciation of SeAAs in biological samples are summarized and a perspective for future developments including sophisticated and innovative applications is discussed. Overall, HPLC-ICP-MS is more applicable than GC/CE-ICP-MS for chiral speciation of SeAAs. In the future, more novel chiral HPLC methods with high enantio-resolution, low cost and robustness, and their more applications in real biological samples analysis are expected. PMID:25130085

  19. Speciation dynamics and bioavailability of metals

    International Nuclear Information System (INIS)

    In this paper the equilibrium approach the so-called 'free-ion activity model' (FIAM) has been applied over and again in the interpretation of the bio-uptake of metals from complex media. One of the prerequisites of the FIAM is that the supply of the bioactive metal species, i.e. the free-ion, towards the surface of the organism is much faster than the actual bioconversion step. Only then will equilibrium between the different metal species in the medium be maintained at any point in space and time and hence will the bulk activity of the free-ion be maintained at the surface. However, there are numerous examples of metal bio-uptake from complex systems where the conversion rates cannot be understood in terms of the bioactive free-metal alone. In such cases it is mandatory that bio-inactive metal complexes contribute to the supply of metal to the bio-interface. Apparently, some complexes are able to dissociate at such a rate that the produced free-metal can significantly contribute to the metal flux towards the bio-surface. The mathematical characterization of the speciation dynamics and bioavailability of metals is discussed

  20. Arsenic Speciation of Terrestrial Invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, M.M.; Koch, I.; Gordon, R.A.; Reimer, K.J. ((Simon)); ((Royal))

    2009-07-01

    The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine sites and one background site in Nova Scotia, Canada. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), were dependent upon the classification of invertebrate. Arsenic species were determined by high-performance liquid chromatography (HPLC) ICP-MS and X-ray absorption spectroscopy (XAS). Invertebrates were found by HPLC ICP-MS to contain predominantly arsenite and arsenate in methanol/water extracts, while XAS revealed that most arsenic is bound to sulfur in vivo. Examination of the spatial distribution of arsenic within an ant tissue highlighted the differences between exogenous and endogenous arsenic, as well as the extent to which arsenic is transformed upon ingestion. Similar arsenic speciation patterns for invertebrate groups were observed across sites. Trace amounts of arsenobetaine and arsenocholine were identified in slugs, ants, and spiders.

  1. Creating bulk nanocrystalline metal.

    Energy Technology Data Exchange (ETDEWEB)

    Fredenburg, D. Anthony (Georgia Institute of Technology, Atlanta, GA); Saldana, Christopher J. (Purdue University, West Lafayette, IN); Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John (Ktech Corporation, Albuquerque, NM); Vogler, Tracy John; Yang, Pin

    2008-10-01

    Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the material's microstructure must be very small to give homogeneous properties across the feature.

  2. A novel method for quantitative determination of aceclofenac in bulk drug and tablets using sodium salicylate as a hydrotropic solubilizing agent

    Directory of Open Access Journals (Sweden)

    R K Maheshwari

    2010-01-01

    Full Text Available In titrimetric analysis costlier organic solvents are more often employed to solubilize the poorly water-soluble drugs. Volatility and pollution are drawbacks of such solvents. Various techniques are employed to enhance the aqueous solubility of poorly water-soluble drugs. Hydrotropic solubilization phenomenon has been widely used to enhance the aqueous solubility of large number of poorly water-soluble drugs. Aqueous solubility of aceclofenac bulk drug [a poorly water-soluble NSAID] was enhanced to a great extent i.e., 400 folds with 2.5 M sodium salicylate. The primary objective of the present investigation was to employ this hydrotropic solution to extract the drug from its dosage forms, precluding the use of costlier organic solvents. The proposed method of analysis is new, simple, accurate, environmentally friendly and reproducible. Statistical data proved the accuracy, reproducibility and the precision of the proposed method. The results of titrimetric analysis by use of hydrotropy compared very well with the results of Pharmacopoeial method.

  3. The chemical speciation and analysis of trace elements in sediment with Neutron Activation Analytical method(NAA) and atomic mass spectrometry

    International Nuclear Information System (INIS)

    In this research, first of all, the analytical methods for the determination of major elements in sediment have been developed with ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The analytical results of major elements (Al, Ca, K, Fe, Mg) with Cool ICP-MS were much better than those with normal ICP-MS. The analytical results were compared with those of NAA (Neutron Activation Analysis). NAA were a little superior to ICP-MS for the determination of major elements in sediment as a non-destructive trace analytical trace analytical method. The analytical methods for the determination of minor elements (Cr, Ce, U, Co, Pb, As, Se) have been also developed with ICP-MS. The analytical results by standard calibration curve with ICP-MS were not accurate due to the matrix interferences. Thus, the internal standard method was applied, then the analytical results for minor elements with ICP-MS were greatly improved. The analytical results obtained by ICP-MS were compared with those obtained by NAA. It showed that the two analytical methods have great capabilities for the determination of minor elements in sediments. Accordingly, the NAA will plan an important role in analysis of environment sample with complex matrix. ICP-MS also will play an important role because it has a great capability for the determination of Pb that could not be determined by NAA

  4. Microscale characterization of sulfur speciation in lake sediments.

    Science.gov (United States)

    Zeng, Teng; Arnold, William A; Toner, Brandy M

    2013-02-01

    Prairie pothole lakes (PPLs) are naturally sulfur-enriched wetlands in the glaciated prairie region of North America. High sulfate levels and dynamic hydrogeochemistry in combination render PPLs a unique environment to explore the speciation of sedimentary sulfur (S). The goals of this research were to define and quantify the solid-phase S pools in PPL sediments and track seasonal dynamics of S speciation. A quantitative X-ray microprobe method was developed based on S 1s X-ray absorption near-edge structure (XANES) spectroscopy and multienergy X-ray fluorescence mapping. Three S pools-pyritic S, reduced organic S (organic mono- and disulfide), and oxidized S (inorganic sulfate, ester sulfate, and sulfonate)-were identified in PPL sediments. No significant seasonal variation was evident for total S, but S speciation showed a seasonal response. During the spring-summer transition, the reduced organic S decreased from 55 to 15 mol %, with a concomitant rise in the oxidized S. During the summer-fall transition, the trend reversed and the reduced organic S grew to 75 mol % at the expense of the oxidized S. The pyritic S, on the other hand, remained relatively constant (∼22 mol %) over time. The seasonal changes in S speciation have strong potential to force the cycling of elements such as mercury in prairie wetlands. PMID:23282039

  5. Development of a reference method for speciation analysis of methylmercury in fish by HPLC-ICPMS and species specific isotope dilution

    International Nuclear Information System (INIS)

    Full text: LNE, the French National Metrology Institute, has established from many years isotope dilution applied to ICPMS to be able to certify reference materials in the fields of environmental monitoring, health and food. The present work shows the method developed for the analysis of methylmercury in fish products. The process was realized with a HPLC coupled to an ICPMS after the extraction of mercury by the use of microwave heating. Double IDMS was involved for quantification. Sources of bias were estimated to be taken into account within the uncertainty budget realized with GUM recommendations. Fresh and lyophilized CRMs were analyzed for method validation. (author)

  6. Speciation by selection: A framework for understanding ecology's role in speciation

    Institute of Scientific and Technical Information of China (English)

    R.Brian LANGERHANS; Rüdiger RIESCH

    2013-01-01

    Speciation research during the last several decades has confirmed that natural selection frequently drives the generation of new species.But how does this process generally unfold in nature? We argue that answering this question requires a clearer conceptual framework for understanding selection's role in speciation.We present a unified framework of speciation,providing mechanistic descriptions of fundamentally distinct routes to speciation,and how these may interact during lineage splitting.Two major categories are recognized:reproductive isolation resulting from (1) responses to selection,"speciation by selection,"or (2) non-selective processes,"speciation without selection." Speciation by selection can occur via three mechanisms:(1) similar selection,(2) divergent selection,and (3) reinforcement selection.Understanding ecology's role in speciation requires uncovering how these three mechanisms contribute to reproductive isolation,and their relative importance compared to non-selective processes,because all three mechanisms can occur side-by-side during speciation.To accomplish this,we highlight examination of groups of organisms inhabiting replicated environmental gradients.This scenario is common in nature,and a large literature illustrates that both parallel and non-parallel responses to similar environments are widespread,and each can result in speciation.This recognition reveals four general pathways of speciation by similar or divergent selection-parallel and nonparallel responses to similar and divergent selection.Altogether,we present a more precise framework for speciation research,draw attention to some under-recognized features of speciation,emphasize the multidimensionality of speciation,reveal limitations of some previous tests and descriptions of speciation mechanisms,and point to a number of directions for future investigation [Current Zoology 59(1):31-52,2013].

  7. Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

    Energy Technology Data Exchange (ETDEWEB)

    Beinhauer, Jana [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Bian, Liangqiao [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Fan, Hui [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); Šebela, Marek [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Kukula, Maciej [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Barrera, Jose A. [Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); and others

    2015-02-09

    Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL{sup −1}, and demonstrated good linearity of R{sup 2} from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL{sup −1}. Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified.

  8. USE OF MICRO X-RAY ABSORPTION SPECTROSCOPY AND DIFFRACTION TO DELINEATE Cr(VI) SPECIATION IN COPR

    Energy Technology Data Exchange (ETDEWEB)

    CHRYSOCHOOU, M.; MOON, D. H.; FAKRA, S.; MARCUS, M.; DERMATAS, D.; CHRISTODOULATOS, C.

    2010-06-22

    The speciation of Cr(VI) in Cromite Ore Processing Residue was investigated by means of bulk XRD, and a combination of micro-XRF, -XAS and -XRD at the Advanced Light Source (ALS), Berkeley, CA, U.S.A.. Bulk XRD yielded one group of phases that contained explicitly Cr(VI) in their structure, Calcium Aluminum Chromium Oxide Hydrates, accounting for 60% of the total Cr(VI). Micro-analyses at ALS yielded complimentary information, confirming that hydrogarnets and hydrotalcites, two mineral groups that can host Cr(VI) in their structure by substitution, were indeed Cr(VI) sinks. Chromatite (CaCrO4) was also identified by micro-XRD, which was not possible with bulk methods due to its low content. The acquisition of micro-XRF elemental maps enabled not only the identification of Cr(VI)-binding phases, but also the understanding of their location within the matrix. This information is invaluable when designing Cr(VI) treatment, to optimize release and availability for reduction.

  9. Bacteria Composition of Aerobic Granular Sludge Under Filamentous Bulking and Control Method of Filamentous Bulking%丝状膨胀好氧颗粒污泥细菌组成及丝状膨胀的控制

    Institute of Scientific and Technical Information of China (English)

    纪树兰; 李建婷; 秦振平; 刘志培; 崔丹红

    2011-01-01

    采用构建16S rDNA克隆文库方法对发生丝状膨胀的好氧颗粒污泥的细菌种群进行研究.结果表明,丝状膨胀的好氧颗粒污泥共包含六大类群,分别是β-proteobacteria(36.23%)、Sphingobacteria(20.29%)、δ-Pro-teobacteria(13.04%)、Flavobacteria(10.14%)、γ-Proteobacteria(1.45%)和Actinobacteria(1.45%),通过序列比对可知好氧颗粒污泥中存在Sphaerotilus natans等丝状菌,但根据所占比例确定其不是导致好氧颗粒污泥丝状膨胀的细菌.对膨胀颗粒污泥外边缘的丝状微生物进一步鉴定,发现它属于丝状真菌.试验验证了进水pH随运行时间降低是导致葡萄糖配水培养好氧颗粒污泥发生丝状膨胀的主要原因.采用缩短运行周期、运行过程中投加NaHCO3和减少曝气量的方法均可预防好氧颗粒污泥的丝状膨胀,但投加碱度是最直接有效的方法,且在发生丝状膨胀初期还可通过该方法控制膨胀.%The bacterial composition of the aerobic granular sludge under filamentous bulking was studied by construction of 16S rDNA clone library.The results indicated that the bacterial community in aerobic granular sludge included 6 major groups: β-proteobacteria,Sphingobacteria,δ-Proteobacteria,Flavobacteria,γ-proteobacteria and Actinobacteria,and their portions were 36.23%,20.29%,13.04%,10.12%,1.45% and 1.45%,respectively.Sequence analysis also indicated that filamentous bacterial such as Sphaerotilus natans existed in aerobic granular sludge,but it was not the main cause of filamentous bulking based on the occurrence frequency of clones in 16S rDNA clone library.Filamentous microorganism from outer edge of aerobic granular sludge was picked out for further identification and was identified to belong to filamentous fungi.Experiment proves that pH decreasing with running time is the main cause for filamentous bulking.Shorten running time of the cycle,adding NaHCO3 to reactor and decreasing aeration

  10. A fast method to estimate speciation parameters in a model of isolation with an initial period of gene flow and to test alternative evolutionary scenarios

    OpenAIRE

    Wilkinson-Herbots, Hilde

    2015-01-01

    We consider a model of "isolation with an initial period of migration" (IIM), where an ancestral population instantaneously split into two descendant populations which exchanged migrants symmetrically at a constant rate for a period of time but which are now completely isolated from each other. A method of Maximum Likelihood estimation of the parameters of the model is implemented, for data consisting of the number of nucleotide differences between two DNA sequences at each of a large number ...

  11. Methods of Determining Lead Speciation in Fly Ash by X-ray Absorption Fine-Structure Spectroscopy and a Sequential Extraction Procedure

    OpenAIRE

    Funatsuki, Atsushi; Takaoka, Masaki; Oshita, Kazuyuki; Takeda, Nobuo

    2012-01-01

    Understanding the chemical state of lead in fly ash generated from a waste thermal treatment is important, since the toxicity and solubility of the element depends on its chemical state. This study identified three potential methods for obtaining quantitative information regarding the chemical state of lead in fly ash: X-ray absorption near edge structure (XANES) analysis, extended X-ray absorption fine structure (EXAFS) analysis, and the sequential extraction procedure. The result of this pr...

  12. Speciation of heavy metals in sediment by conventional, ultrasound and microwave assisted single extraction methods: A comparison with modified sequential extraction procedure

    International Nuclear Information System (INIS)

    Sequential extraction procedure proposed by the European Standards, Measurements and Testing (SM and T) Program, formerly the Community Bureau of Reference (BCR), has been applied for the heavy metals (HMs) partitioning in fresh water lake sediment samples. The results obtained by conventional sequential extraction BCR method (SEB) for Cd, Cu, Cr, Ni, Pb and Zn were compared with those estimated from three alternative single extractions, conventional (CSE), ultrasonic (USE) and microwave assisted (MSE), using identical operating conditions applied in each individual BCR fraction and validated by the CRM BCR 701. Extractable HMs contents obtained by all compared methodologies were measured by atomic absorption spectrometery. With the use of compromised sonication and microwave conditions, steps 1-3 of the sequential extraction (excluding the hydrogen peroxide digestion in step 3) could be completed between 15-30 min using ultrasonic bath, while 60-120 s were required for MSE. The total extractable metal contents obtained by three single extractions ranged from 75.1% to 114.0% except Cr in first step, which was extracted (125.3%) by MSE method as compared to those obtained by SEB procedure. The precision of the proposed BCR single extraction methods (expressed as RSD%) was found in the range of (3.99-9.6%) for all metals

  13. DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF GLIPIZIDE AND METFORMIN IN BULK DRUGS AND TABLET DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    D.Triveni

    2012-09-01

    Full Text Available The present work describes development and validation of simple, precise and accurate reversed-phase liquid chromatographic method for simultaneous estimation of glipizide and metformin hydrochloride in both bulk drugs and pharmaceutical dosage forms. The chromatographic separation was achieved on (Enable, symmetry C18, 250mm x 4.6mm, 5μ analytical column. A mobile phase consisting mixture of potassium dihydrogen phosphate (0.2M, pH 5.8 adjusted with dilute sodium hydroxide and acetonitrile in ratio (60:40 v/v at flow rate of 1.0ml/min and UV detector wavelength 258 nm. The retention time of glipizide and metformin Hcl was found to be 7.9 and 2.5 minutes respectively.The method was successfully validated in accordance to ICH guidelines for accuracy, precision, specificity, linearity, ruggedness and robustness. The linear regression analysis data for calibration plots showed good linear relationship in the concentration range 60-140 μg/mL for both glipizide and metformin hydrochloride.

  14. Application of a Validated Stability-Indicating LC Method for the Simultaneous Estimation of Tapentadol and Its Process-Related Impurities in Bulk and Its Dosage Form

    Directory of Open Access Journals (Sweden)

    Singaram Kathirvel

    2013-01-01

    Full Text Available Described is a first reported, simple, rapid, selective, and isocratic stability-indicating RP-LC method for the quantitative determination of tapentadol and its related substances in bulk samples and pharmaceutical dosage forms in the presence of its two process-related impurities. Chromatographic separation was achieved on the reversed phase, Enable column (C18 (5-μm, 250 × 4.6 mm, i.d. at ambient temperature using a mobile phase consisting of 0.02 M potassium dihydrogen orthophosphate (adjusted to pH 6 with 1 M KOH and acetonitrile (80 : 20, v/v. Flow rate was 1 mL/min and retention time was found to be 7.7 ± 0.05 min. Quantitation was achieved with UV detection at 215 nm based on peak area with linear calibration curves at concentration range 75–300 μg/mL. Forced degradation studies were performed, in accordance with ICH guidelines, using acidic, alkaline, oxidative, neutral, photolytic, and thermal conditions. The drug was found to be stable under all the conditions. The developed method was validated in terms of precision, robustness, recovery, and limits of detection and quantitation. Regression analysis shows an “r” value (correlation coefficient of greater than 0.999 for tapentadol and two potential impurities.

  15. 密集烤房不同装烟方式比较研究%Comparison of Tobacco Leaf Loading Methods in Bulk Curing Barn

    Institute of Scientific and Technical Information of China (English)

    孙曙光; 周童; 顾会战; 彭毅; 汪健; 王鹏; 陈利平

    2012-01-01

    [目的]探索密集烤房的最佳装烟方式.[方法]以密集烤房挂杆方式为对照,比较研究了托架式烟夹、框架散叶、散叶插签装烟方式的配套设备成本、装烟量、用工量、烤后烟叶经济性状、能耗成本等状况.[结果]托架式烟夹、框架散叶、散叶插签装烟方式节能省工效果明显,3种装烟方式装烟量最大可提高71.43%,初烤烟经济性状均有所提高,符合现代烟草农业集约化和可持续发展要求.[结论]研究可为密集烤房不同装烟方式的优化提供参考依据.%[Objective] To explore the best tobacco leaf loading method. [Method] With hang poles as control group, bracket type smoke clamp, framework loose leaf and loose leaf cutting sign loading tobacco patterns were tested in bulk curing barn about corollary equipment cost, pack smoke volume, the employment quantity, roast tobacco leaf after economic characters, energy consumption cost. [Result] The results showed that bracket type smoke clamp, framework loose leaf and loose leaf cutting sign were much better than hang poles in energy and worker saving. Because largest amount of the three tobacco leaf loading method can be increased by 71. 43 % and initial flue-cured tobacco economic characters are improved so they accord with the modern tobacco agriculture. [Conclusion] The study provides reference basis for optimization of different tobacco loading method.

  16. Uranium speciation in Fernald soils

    International Nuclear Information System (INIS)

    This report details progress made from January 1 to May 31, 1992 in this analytical support task to determine the speciation of uranium in contaminated soil samples from the Fernald Environmental Management Project site under the auspices of the Uranium in Soils Integrated Demonstration funded through the US DOE's Office of Technology Development. The authors' efforts have focused on characterization of soil samples collected by S.Y. Lee (Oak Ridge National Laboratory) from five locales at the Fernald site. These were chosen to sample a broad range of uranium source terms. On the basis of x-ray absorption spectroscopy data, they have determined that the majority of uranium (> 80--90%) exists in the hexavalent oxidation state for all samples examined. This is a beneficial finding from the perspective of remediation, because U(VI) species are more soluble in general than uranium species in other oxidation states. Optical luminescence data from many of the samples show the characteristic structured yellow-green emission from the uranyl (UO22+) moiety. The luminescence data also suggest that much of the uranium in these soils is present as well-crystallized UO22+ species. Some clear spectroscopic distinctions have been noted for several samples that illustrate significant differences in the speciation (1) from site to site, (2) within different horizons at the same site, and (3) within different size fractions of the soils in the same horizon at the same site. This marked heterogeneity in uranyl speciation suggests that several soil washing strategies may be necessary to reduce the total uranium concentrations within these soils to regulatory limits

  17. Arsenic speciation in edible mushrooms.

    Science.gov (United States)

    Nearing, Michelle M; Koch, Iris; Reimer, Kenneth J

    2014-12-16

    The fruiting bodies, or mushrooms, of terrestrial fungi have been found to contain a high proportion of the nontoxic arsenic compound arsenobetaine (AB), but data gaps include a limited phylogenetic diversity of the fungi for which arsenic speciation is available, a focus on mushrooms with higher total arsenic concentrations, and the unknown formation and role of AB in mushrooms. To address these, the mushrooms of 46 different fungus species (73 samples) over a diverse range of phylogenetic groups were collected from Canadian grocery stores and background and arsenic-contaminated areas. Total arsenic was determined using ICP-MS, and arsenic speciation was determined using HPLC-ICP-MS and complementary X-ray absorption spectroscopy (XAS). The major arsenic compounds in mushrooms were found to be similar among phylogenetic groups, and AB was found to be the major compound in the Lycoperdaceae and Agaricaceae families but generally absent in log-growing mushrooms, suggesting the microbial community may influence arsenic speciation in mushrooms. The high proportion of AB in mushrooms with puffball or gilled morphologies may suggest that AB acts as an osmolyte in certain mushrooms to help maintain fruiting body structure. The presence of an As(III)-sulfur compound, for the first time in mushrooms, was identified in the XAS analysis. Except for Agaricus sp. (with predominantly AB), inorganic arsenic predominated in most of the store-bought mushrooms (albeit with low total arsenic concentrations). Should inorganic arsenic predominate in these mushrooms from contaminated areas, the risk to consumers under these circumstances should be considered. PMID:25417842

  18. Speciation of Pb in industrially polluted soils

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ottosen, Lisbeth M.; Pedersen, Anne Juul

    2006-01-01

    This study was aimed at elucidating the importance of original Pb-speciation versus soil-characteristics to mobility and distribution of Pb in industrially polluted soils. Ten industrially polluted Danish surface soils were characterized and Pb speciation was evaluated through SEM-EDX studies...

  19. METHOD DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF ESCITALOPRAM OXALATE AND ETIZOLAM IN BULK AND ITS PHARMACEUTICAL FORMULATIONS

    OpenAIRE

    Kalpana Nekkala*, V Shanmukha Kumar J1, D Ramachandran2, Ganji Ramanaiah2 and Ganta Srinivas

    2014-01-01

    A new rapid, precise and sensitive reverse phase high performance liquid chromatographic (RP-HPLC) method has been developed and validated for the estimation of Escitalopram and Etizolam simultaneously in combined dosage form. The two components Escitalopram and Etizolam were well resolved on an isocratic method, C18 column, utilizing a mobile phase composition of acetonitrile: methanol: 0.02M ammonium acetate buffer (30:20:50), v/v, pH 4.5) at a flow rate of 1.0 mL/min with UV detection at 2...

  20. Novel speciation method based on Diffusive Gradients in Thin Films for in situ measurement of uranium in the vicinity of the former uranium mining sites.

    Science.gov (United States)

    Drozdzak, Jagoda; Leermakers, Martine; Gao, Yue; Phrommavanh, Vannapha; Descostes, Michael

    2016-07-01

    The Diffusive Gradients in Thin Films (DGT) technique using PIWBA resin (The Dow Chemical Company) was developed and validated for the measurement of uranium (U) concentration in natural and uranium mining influenced waters. The U uptake on the PIWBA resin gel was 97.3 ± 0.4% (batch method; Vsol = 5 mL; [U] = 20 μg L(-1); 0.01 M NaNO3; pH = 7.0 ± 0.2). The optimal eluent was found to be HNO3conc/70 °C with an elution efficiency of 88.9 ± 1.4%. The laboratory DGT investigation demonstrated that the PIWBA resin gel exhibits a very good performance across a wide range of pH (3-9) and ionic strength (0.001-0.7 M NaNO3) at different time intervals. Neither effect of PO4(3-) (up to 1.72 × 10(-4) M), nor of HCO3(-) (up to 8.20 × 10(-3) M) on the quantitative measurement of uranium by DGT-PIWBA method were observed. Only at very high Ca(2+) (2.66 × 10(-4) M), and SO4(2-) (5.55 × 10(-4) M) concentration, the U uptake on DGT-PIWBA was appreciably lessened. In-situ DGT field evaluation was carried out in the vicinity of three former uranium mining sites in France (Loire-Atlantique and Herault departments), which employ different water treatment technologies and have different natural geochemical characteristics. There was a similar or inferior U uptake on DGT-Chelex(®)-100 in comparison with the U accumulation on a DGT-PIWBA sampler. Most likely, the performance of Chelex(®)-100 was negatively affected by a highly complex matrix of mining waters. The high concentration and identity of co-accumulating analytes, typical for the mining environment, did not have a substantial impact on the quantitative uptake of labile U species on DGT- PIWBA. The use of the polyphenol impregnated anion exchange resin leads to a significant advancement in the application and development of the DGT technique for determination of U in the vicinity of the former uranium mining sites. PMID:27070846

  1. Rapid parapatric speciation on holey adaptive landscapes

    CERN Document Server

    Gavrilets, S; Vose, M D; Gavrilets, Sergey; Li, Hai; Vose, Michael D.

    1998-01-01

    A classical view of speciation is that reproductive isolation arises as a by-product of genetic divergence. Here, individual-based simulations are used to evaluate whether the mechanisms implied by this view may result in rapid speciation if the only source of genetic divergence are mutation and random genetic drift. Distinctive features of the simulations are the consideration of the complete process of speciation (from initiation until completion), and of a large number of loci, which was only one order of magnitude smaller than that of bacteria. It is demonstrated that rapid speciation on the time scale of hundreds of generations is plausible without the need for extreme founder events, complete geographic isolation, the existence of distinct adaptive peaks or selection for local adaptation. The plausibility of speciation is enhanced by population subdivision. Simultaneous emergence of more than two new species from a subdivided population is highly probable. Numerical examples relevant to the theory of ce...

  2. DEVELOPMENT AND VALIDATION OF FIRST ORDER DERIVATIVE UV SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS ESTIMATION OF PROPRANOLOL HYDROCHLORIDE AND FLUNARIZINE DIHYDROCHLORIDE IN BULK AND COMBINED DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    Wagh Dipmala Dilip

    2013-06-01

    Full Text Available The first order derivative of UV spectrometry method for simultaneous determination of Propranolol hydrochloride (PRO and Flunarizine dihydrochloride (FLU in pure bulk drug and combined dosage form was found to be simple, accurate, fast, precise and reproducible. The first derivative values measured at 289nm for PRO and 253nm for FLU. The linearity for zero order derivative method was carried out by using the concentration range 4-28µg/ml for PRO and 3-7µg/ml for FLU. The coefficient correlation of PRO and FLU for zero order was found to be 0.9995 and 0.9991 respectively. At zero crossing point of PRO (289nm FLU showed a measurable derivative absorbance where as at the zero crossing point of FLU (253nm, PRO showed appreciable derivative absorbance value. The coefficient correlation of PRO and FLU for first order derivative was found to be 0.9991 and 0.9995 respectively. Precision study showed that % RSD was within the range of acceptable limits (<2. The % recovery for PRO and FLU was found to be in the range of 98-102% and 100-101% respectively. The percentage assay was found to be as 99.5 and 100.12% for PRO and FLU. The results of analysis have been validated as per ICH Q2 (R1 guidelines. This method has applied successfully for the determination of PRO and FLU in its combination with a high percentage of recovery good accuracy and precision.

  3. Effects of graphite doping on critical current density and microstructure of MgB2 bulks by an improved Mg-diffusion method

    International Nuclear Information System (INIS)

    abstract: A series of graphite-doped MgB2 bulks with high density have been successfully prepared by an improved Mg-diffusion method in ambient pressure. The effects of graphite doping on lattice parameters, Tc, Jc and microstructure of MgB2 have been investigated. The results show that compared to the nano-C-doped or CNTs-doped MgB2, C is not easy to substitute B in graphite-doped MgB2. However, at the same C content, the graphite-doped MgB2 has a higher Jc. At 10 K and self-field, the Jc for MgB1.985C0.015 reaches 0.58 MA/cm2. For the MgB1.945C0.055, at 5 K, 7 T and 10 K, 6 T the Jc achieves 10,000 A/cm2 which is two orders of magnitude higher than that for the undoped sample. In addition to improving electron scattering and intergranular connectivity, the unreacted graphite in the graphite-doped MgB2 is proposed to be responsible to the excellent Jc properties of MgB2 in high fields, due to depressed grain growth and enhanced grain boundary flux pinning

  4. Quantitative estimation of diacerein in bulk and in capsule formulation using hydrotropic solubilizing agents by UV-spectrophotometry and the first order derivative using the area under curve method

    OpenAIRE

    Pandey, Ramchandra; Pravin O. Patil; Patil, Manohar U.; Deshmukh, Prashant K.; Sanjay B. Bari

    2012-01-01

    Purpose: This study was designed to develop and validate two simple, rapid, and economical UV-spectrophotometric and the first-order derivative methods using the area under curve method for estimation of diacerein in bulk and in capsule formulation. Materials and Methods: In this study, hydrotrophic solution of 8 M urea and 0.5 M potassium citrate were employed as the solubilizing agent to solubilize a poorly water-soluble drug, diacerein. In the UV-spectrophotometry method, two wavelengths 2...

  5. Speciation of strontium and plutonium in aquatic ecosystems

    International Nuclear Information System (INIS)

    In 1995 VTT (Technical Research Centre of Finland) and the Laboratory of Radiochemistry of the University of Helsinki initiated jointly a project on the speciation of 90Sr and 239Pu. The work has two goals. One is to develop methods for the general classification of the chemical species of radionuclides in water. The second goal is to get more insight in the behaviour of 90Sr and 239Pu in water ecosystems. At present literature reviews on the behaviour of 90Sr and 239Pu have been prepared, the classification method is almost ready, and some laboratory simulations on the speciation of 90Sr have been done. The work will continue at least this year, and the years 1997 and 98 also, if funding will he provided. (author)

  6. Speciation of lead in contaminated soil under the influence of plants and phosphate amendment type

    Science.gov (United States)

    Diyab, C.; Juillot, F.; Dumat, C.; Morin, G.; Benedetti, M.; Mariotti, A.

    2003-05-01

    The toxicity of an element and its behaviour depend on its chemical form (speciation) and concentration. The objective of our work is to study the speciation of Pb under the influence of phosphate amendments (solide, soluble) and type of plants: peas, tomato (pH variation, organic acid complexes formation) in a polluted soil near one of Europe's largest lead contaminated area in the north of France. Chemical and physical methods were used to determine the speciation of lead in rhizospheric soil (chemical extraction, μFX, EXAFS, SEM.). The formation of lead phosphate complexe was confirmed in rhizospheric soil of both plants. Quantity and chemical structure of phosphate lead complexe formed in soil, varied with the type of plante and phosphate amendement added. Analysis of organic acids secreted by the two plantes were performed to understand the effect of organic acids on the speciation of lead in the rhizospheric soil.

  7. Electrochemical studies of metal speciation in marine and estuarine conditions

    International Nuclear Information System (INIS)

    The degree of speciation of trace metals detected depends to some extent on the analytical method used. Possible changes in organic-metal interactions may be due to complex dissociation by competition with added chelators. Results obtained with cathodic stripping voltammetry are discussed in terms of interactions of dissolved organic ligands, and colloidal particles with dissolved metal ions. Estuarine data for copper, uranium, vanadium and iron are presented

  8. Electrochemical studies of metal speciation in marine and estuarine conditions

    International Nuclear Information System (INIS)

    The degree of speciation of trace metals detected depends to some extent on the analytical method used. Possible changes in organic-metal interactions may be due to complex dissociation by competition with added chelators. Results obtained with cathodic stripping voltammetry are discussed in terms of interactions of dissolved organic ligands, and colloidal particles with dissolved metal ions. Estuarine data for copper, uranium, vanadium and iron are presented. (author)

  9. Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

    OpenAIRE

    Harris, Hugh H; Stefan Vogt; Witting, Paul K.; Aitken, Jade B.; Lydia Finney; Weekley, Claire M.

    2013-01-01

    Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative appro...

  10. Oxidation-state speciation of

    Science.gov (United States)

    Hu; Heineman

    2000-06-01

    The analytical utility of chemically modified microelectrodes for oxidation-state speciation of redox couples by cyclic voltammetry has been explored. [Re(I)(DMPE)3]+/[Re(II)(DMPE)3]2+, where DMPE = 1,2-bis(dimethylphosphino)ethane, was studied at carbon-fiber microelectrodes of approximately 5 microm in radius coated with Nafion-entrapped solgel-derived silica (Nafion-silica) composite. The results are compared with cyclic voltammetry of [Fe(CN)6]3-/[Fe(CN)6]4- at bare carbon-fiber microelectrodes. At both microelectrodes, the cathodic and anodic limiting currents are linearly proportional to the concentrations of the reducible and oxidizable species of a redox couple, respectively. The shape of the cyclic voltammogram and the magnitude of the steady-state limiting current are not affected by the potential at which the scan starts. Speciation of both forms of a redox couple could be achieved voltammetrically at the microelectrodes. However, a considerably slower scan rate was required to achieve steady state at the modified electrode because of the smaller diffusion coefficients of [Re(I)(DMPE)3]+ and [Re(II)(DMPE)3]2+ in the Nafion-silica composite. The detection limit at the modified electrode was considerably lower (5 x 10(-9) M for [Re(I)(DMPE)3]+) than at the bare electrode (6 x 10(-5) M for [Fe(CN)6]3- and [Fe(CN)6]4-) because of the substantial preconcentration of [Re(I)(DMPE)3]+ by the Nafion-silica composite. PMID:10857611

  11. Looking for a bulk point

    CERN Document Server

    Maldacena, Juan; Zhiboedov, Alexander

    2015-01-01

    We consider Lorentzian correlators of local operators. In perturbation theory, singularities occur when we can draw a position-space Landau diagram with null lines. In theories with gravity duals, we can also draw Landau diagrams in the bulk. We argue that certain singularities can arise only from bulk diagrams, not from boundary diagrams. As has been previously observed, these singularities are a clear diagnostic of bulk locality. We analyze some properties of these perturbative singularities and discuss their relation to the OPE and the dimensions of double-trace operators. In the exact nonperturbative theory, we expect no singularity at these locations. We prove this statement in 1+1 dimensions by CFT methods.

  12. Gamma probe dry bulk densities

    International Nuclear Information System (INIS)

    The gamma density probe is a useful instrument for measuring water content in small volumes of soil. Essentially, the gamma probe measures the density of the soil and water between a source and a detector. To transpose the gamma densities into water content, the dry bulk density of the soil is needed. A nondestructive method for estimating dry bulk densities for use with the gamma probe is proposed. The procedure is based on the assumption that water content values in a field dry condition were more stable than the dry bulk density values and could be transferred from one point to another. The procedure was successfully used on three areas in Reynolds Creek Experimental Watershed in southwest Idaho. (U.S.)

  13. Development of improved method for isolation of Mycobacterium avium subsp. paratuberculosis from bulk tank milk: Effect of age of milk, centrifugation, and decontamination

    OpenAIRE

    Gao, Anli; Odumeru, Joseph; Raymond, Melinda; Mutharia, Lucy

    2005-01-01

    Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne’s disease in cattle and it has been suggested that this organism may be associated with Crohn’s disease in humans. Cows at the advanced stage of the disease shed this organism into both their milk and feces. The objective of this study was to develop a more efficient procedure for isolating MAP from bulk tank raw milk. Bulk tank raw milk (50 mL) samples 3 to 13 d old after collection without spiking were investi...

  14. Comparação de métodos de medida da densidade do solo = Comparison of methods to evaluate soil bulk density.

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Pires

    2011-01-01

    Full Text Available A densidade do solo (ds tem sido usada como um parâmetro importante de caracterização física da estrutura do solo e como um indicador de sua compactação. Este trabalho teve como objetivo comparar os valores de ds obtidos através de métodos convencionais, como torrão parafinado (MTP e anel volumétrico (MAV, e nucleares, como tomografia computadorizada (MTC, atenuação gama (MAG e sonda de superfície nêutron-gama (MSN. Foram feitas coletas de amostras em áreas submetidas às práticas de manejo de plantio convencional e plantio direto. Para as análises pelos MAV, MTP, MTC e MAG foram coletadas 16 amostras na camada superficial do solo e para o MSN foramrealizadas leituras em 16 pontos distintos ao longo da área experimental. Os maiores valores de ds foram obtidos para os MTP, MTC e MAG (plantio convencional não diferindo estatisticamente entre si. Os menores valores de ds foram obtidos para os MSN e MAV não diferindo estatisticamente entre si. Com relação ao plantio direto foram comparados somente os MAV e MAG com os valores de ds diferindo estatisticamente entre si.Soil bulk density (ds is traditionally used as an indicator of soil structure and soil compaction. The objective of this work was to compare ds values obtained through conventional methods like paraffinsealed clod (MTP and volumetric ring (MAV, and nuclear methods like computerized tomography (MTC, gamma-ray attenuation (MAG and neutron-gamma surface gauge (MSN. Soil samples were collected in areas under conventional tillage and no-tillage systems. Sixteen samples were collected in the soil surface layer for the analyses by the MAV, MTP, MTC, and MAG. For the MSN, sixteen readings were carried out throughout the experimental area. The highest ds values for the conventional tillage system were obtained for the MTP, MPC, and MAG, without significant differences. Also the statistic test indicates that the lowest ds values obtained for the MSN and MAV did not differ

  15. Detecting and quantifying lewisite degradation products in environmental samples using arsenic speciation

    Energy Technology Data Exchange (ETDEWEB)

    Bass, D.A.; Yaeger, J.S.; Kiely, J.T.; Crain, J.S.; Shem, L.M.; O`Neill, H.J.; Gowdy, M.J. [Argonne National Lab., IL (United States); Besmer, M.; Mohrman, G.B. [Rocky Mountain Arsenal, Commerce City, CO (United States)

    1995-12-31

    This report describes a unique method for identifying and quantifying lewisite degradation products using arsenic (III) and arsenic (IV) speciation in solids and in solutions. Gas chromatographic methods, as well as high-performance liquid chromatographic methods are described for separation of arsenic species. Inductively coupled plasma-mass spectrographic methods are presented for the detection of arsenic.

  16. Trace mercury speciation in specific Antarctic soils

    Czech Academy of Sciences Publication Activity Database

    Zvěřina, O.; Červenka, R.; Šimůnek, J.; Coufalík, Pavel; Kuta, J.; Komárek, J.

    2015. s. 261-261. [Colloquium Spectroscopicum Internationale /39./. 30.08.2015-03.09.2015, Figueira da Foz] Institutional support: RVO:68081715 Keywords : mercury * speciation * Antarctica Subject RIV: CB - Analytical Chemistry, Separation

  17. NICKEL SPECIATION OF RESIDUAL OIL ASH

    Science.gov (United States)

    EPA GRANT NUMBER: R827649C002Title: Nickel Speciation Of Residual Oil AshInvestigators: Kevin C. Galbreath, John Won, Frank E. Huggins, Gerald P. Huffman, Christopher J. Zygarlicke, Donald L. TomanInstitution: University of North Dakota<...

  18. Pb speciation versus TCLP release in army firing range soils

    International Nuclear Information System (INIS)

    A series of soil parameter and mineralogical investigative techniques were applied to assess the Pb speciation in four US Army firing range soils that presented significantly different Pb leaching regimes and soil characteristics. Soil gradation tests were complemented by total chemical analyses, X-ray powder diffraction (XRPD), Rietveld quantification, optical microscopy and scanning electron microscopy (SEM) analyses. The bulk geotechnical, mineralogical and chemical analyses pointed to two possible Pb retention mechanisms: precipitation as lead carbonate and sorption in the case of fine-grained soils. Lead speciation and mobility was further investigated by the toxicity characteristic leaching procedure (TCLP) and sequential extraction test (SET). As the TCLP Pb concentrations did not necessarily reflect the total Pb analysis of the soils, the Pb leachability ratio (TCLP/total) was found to be controlled by soil mineralogy and its response to changes in system pH. Geochemical modeling, using Visual MINTEQ, was employed to evaluate the mechanisms that controlled the observed TCLP Pb leaching behavior. It was found that lead carbonate precipitation/dissolution reactions controlled Pb TCLP leachability in all soils, while sorptive phenomena did not seem to play a role even in the case of fine-grained soils. More specifically, TCLP Pb leachability was controlled by the pH, the available Pb and the available carbonate in solution. This indicates that geochemical modeling strongly complimented TCLP Pb analyses. Thus, geochemical modeling is an important assessment tool to evaluate the magnitude of site-specific Pb-related environmental problems in firing range soils. Carbonation reactions, involving metallic Pb, that occur during the SET obscure its ability to reliably ascertain Pb speciation. More specifically, SET lumps the extractable Pb into predetermined phase categories that may not be truly representative of the actual soil mineralogy or dominant forms of Pb in

  19. Electrochemical metal speciation in colloidal dispersions.

    OpenAIRE

    Wonders, J.H.A.M.

    1995-01-01

    The term "heavy metals" is connected with toxicity. They form strong complexes with enzymes, other proteins and DNA in living organisms, which causes dysfunctioning and hence poisoning. In combination with the uptake mechanism of the organism, speciation of heavy metal determines the bio-availability of heavy metals. In the environment, heavy metals are complexed by soil particles or molecules of organic and inorganic origin. This thesis deals with the speciation and the binding characteristi...

  20. Getting a Whiff of Speciation by Reinforcement

    OpenAIRE

    Ortiz-Barrientos Daniel; Counterman Brian A

    2004-01-01

    Reinforcement occurs when natural selection strengthens behavioral discrimination to prevent costly interspecies matings, such as when matings produce sterile hybrids. This evolutionary process can complete speciation, thereby providing a direct link between Darwin's theory of natural selection and the origin of new species. Here, by examining a case of speciation by reinforcement in Drosophila, we present the first high-resolution genetic study of variation within species for female mating d...

  1. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using advanced laser-based highly sensitive spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been performed for the chemical speciation of actinide in an aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. (1) Development of TRLFS technology for chemical speciation of actinides, (2) Development of LIBD technology for measuring solubility of actinides, (3) Chemical speciation of plutonium complexes by using a LWCC system, (4) Development of LIBS technology for the quantitative analysis of actinides, (5) Development of technology for the chemical speciation of actinides by CE, (6) Evaluation on the chemical reactions between actinides and humic substances, (7) Chemical speciation of actinides adsorbed on metal oxides surfaces, (8) Determination of actinide source terms of spent nuclear fuel

  2. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using highly sensitive and advanced laser-based spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been applied for the chemical speciation of actinide in aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. Development of TRLFS technology for the chemical speciation of actinides, Development of laser-induced photo-acoustic spectroscopy (LPAS) system, Application of LIBD technology to investigate dynamic behaviors of actinides dissolution reactions, Development of nanoparticle analysis technology in groundwater using LIBD, Chemical speciation of plutonium complexes by using a LWCC system, Development of LIBS technology for the quantitative analysis of actinides, Evaluation on the chemical reactions between actinides and humic substances, Spectroscopic speciation of uranium-ligand complexes in aqueous solution, Chemical speciation of actinides adsorbed on metal oxides surfaces

  3. Speciation and distribution of arsenic and localization of nutrients in rice grains

    Energy Technology Data Exchange (ETDEWEB)

    Lombi, E.; Scheckel, K.G.; Pallon, J.; Carey, A.M.; Zhu, Y.G.; Meharg, A.A. (EPA); (UCopenhagen); (Aberdeen); (Lund); (Chinese Aca. Sci.)

    2012-09-05

    Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques ({mu}-XANES, {mu}-X-ray fluorescence ({mu}-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.

  4. Estimating trait-dependent speciation and extinction rates from incompletely resolved phylogenies.

    Science.gov (United States)

    FitzJohn, Richard G; Maddison, Wayne P; Otto, Sarah P

    2009-12-01

    Species traits may influence rates of speciation and extinction, affecting both the patterns of diversification among lineages and the distribution of traits among species. Existing likelihood approaches for detecting differential diversification require complete phylogenies; that is, every extant species must be present in a well-resolved phylogeny. We developed 2 likelihood methods that can be used to infer the effect of a trait on speciation and extinction without complete phylogenetic information, generalizing the recent binary-state speciation and extinction method. Our approaches can be used where a phylogeny can be reasonably assumed to be a random sample of extant species or where all extant species are included but some are assigned only to terminal unresolved clades. We explored the effects of decreasing phylogenetic resolution on the ability of our approach to detect differential diversification within a Bayesian framework using simulated phylogenies. Differential diversification caused by an asymmetry in speciation rates was nearly as well detected with only 50% of extant species phylogenetically resolved as with complete phylogenetic knowledge. We demonstrate our unresolved clade method with an analysis of sexual dimorphism and diversification in shorebirds (Charadriiformes). Our methods allow for the direct estimation of the effect of a trait on speciation and extinction rates using incompletely resolved phylogenies. PMID:20525612

  5. Selenium speciation in flue desulfurization residues

    Institute of Scientific and Technical Information of China (English)

    Liping Zhong; Yan Cao; Wenying Li; Kechang Xie; Wei-Ping Pan

    2011-01-01

    Flue gas from coal combustion contains significant amounts of volatile selenium (Se).The capture of Se in the flue gas desulfurization (FGD) scrubber unit has resulted in a generation of metal-laden residues.It is important to determine Se speciation to understand the environmental impact of its disposal.A simple method has been developed for selective inorganic Se(Ⅳ), Se(Ⅵ) and organic Se determination in the liquid-phase FGD residues by hydride generation atomic fluorescence spectrometry (AFS).It has been determined that Se(Ⅳ), Se(Ⅵ) and organic Se can be accurately determined with detection limits (DL) of 0.05, 0.06 and 0.06 μg/L, respectively.The accuracy of the proposed method was evaluated by analyzing the certified reference material, NIST CRM 1632c, and also by analyzing spiked tap-water samples.Analysis indicates that the concentration of Se is nigh in FGD liquid residues and primarily exists in a reduced state as selenite (Se(Ⅳ)).The toxicity of Se(Ⅳ) is the strongest of all Se species.Flue gas desulfurization residues pose a serious environmental risk.

  6. Selenium speciation in flue desulfurization residues.

    Science.gov (United States)

    Zhong, Liping; Cao, Yan; Li, Wenying; Xie, Kechang; Pan, Wei-Ping

    2011-01-01

    Flue gas from coal combustion contains significant amounts of volatile selenium (Se). The capture of Se in the flue gas desulfurization (FGD) scrubber unit has resulted in a generation of metal-laden residues. It is important to determine Se speciation to understand the environmental impact of its disposal. A simple method has been developed for selective inorganic Se(IV), Se(VI) and organic Se determination in the liquid-phase FGD residues by hydride generation atomic fluorescence spectrometry (AFS). It has been determined that Se(IV), Se(VI) and organic Se can be accurately determined with detection limits (DL) of 0.05, 0.06 and 0.06 microg/L, respectively. The accuracy of the proposed method was evaluated by analyzing the certified reference material, NIST CRM 1632c, and also by analyzing spiked tap-water samples. Analysis indicates that the concentration of Se is high in FGD liquid residues and primarily exists in a reduced state as selenite (Se(IV)). The toxicity of Se(IV) is the strongest of all Se species. Flue gas desulfurization residues pose a serious environmental risk. PMID:21476358

  7. A NOVEL METHOD FOR QUANTITATIVE DETERMINATION OF ACECLOFENAC IN BULK DRUG AND TABLETS USING SODIUM SALICYLATE AS A HYDROTROPIC SOLUBILIZING AGENT

    OpenAIRE

    R. K. Maheshwari; Shruti Moondra

    2010-01-01

    In titrimetric analysis costlier organic solvents are more often employed to solubilize the poorly water-soluble drugs. Volatility and pollution are drawbacks of such solvents. Various techniques are employed to enhance the aqueous solubility of poorly water-soluble drugs. Hydrotropic solubilization phenomenon has been widely used to enhance the aqueous solubility of large number of poorly water-soluble drugs. Aqueous solubility of aceclofenac bulk drug [a poorly water-soluble NSAID] was enha...

  8. Preparation of a bulk Fe{sub 83}B{sub 17} soft magnetic alloy by undercooling and copper-mold casting methods

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Changlin, E-mail: ycl@nwpu.edu.cn; Sheng, Gang; Chen, Guiyun; Liu, Feng

    2013-11-15

    Bulk Fe{sub 83}B{sub 17} eutectic alloy rods with diameters up to 3 mm were prepared by undercooling solidification combined with Cu-mold casting. The results showed that the rapid solidification led to an increase in the nucleation rate, an inhibition of the grain growth and a competition between a stable Fe{sub 2}B phase and a metastable Fe{sub 3}B phase. Then, pure nano-lamellar eutectic microstructures and the metastable Fe{sub 3}B phase were successfully obtained in as-solidified alloys, which resulted in improved soft magnetic properties. - Highlights: • Pure nano-lamellar eutectic structure was directly formed in the bulk Fe-B alloys. • The metastable Fe{sub 3}B phase was directly formed in the bulk Fe-B alloys. • Undercooling solidification combined with Cu-mold casting was applied. • The information on bcc Fe, Fe{sub 2}B and Fe{sub 3}B-magnetism relationship was provided. • Nano-lamellar eutectic structures enhance the soft magnetic properties.

  9. Development of a multiple bulked segregant analysis (MBSA) method used to locate a new stem rust resistance gene (Sr54) in the winter wheat cultivar Norin 40.

    Science.gov (United States)

    Ghazvini, Habibollah; Hiebert, Colin W; Thomas, Julian B; Fetch, Thomas

    2013-02-01

    An important aspect of studying putative new genes in wheat is determining their position on the wheat genetic map. The primary difficulty in mapping genes is determining which chromosome carries the gene of interest. Several approaches have been developed to address this problem, each with advantages and disadvantages. Here we describe a new approach called multiple bulked segregant analysis (MBSA). A set of 423 simple sequence repeat (SSR) markers were selected based on profile simplicity, frequency of polymorphism, and distribution across the wheat genome. SSR primers were preloaded in 384-well PCR plates with each primer occupying 16 wells. In practice, 14 wells are reserved for "mini-bulks" that are equivalent to four gametes (e.g. two F(2) individuals) comprised of individuals from a segregated population that have a known homozygous genotype for the gene of interest. The remaining two wells are reserved for the parents of the population. Each well containing a mini-bulk can have one of three allele compositions for each SSR: only the allele from one parent, only the allele from the other parent, or both alleles. Simulation experiments were performed to determine the pattern of mini-bulk allele composition that would indicate putative linkage between the SSR in question and the gene of interest. As a test case, MBSA was employed to locate an unidentified stem rust resistance (Sr) gene in the winter wheat cultivar Norin 40. A doubled haploid (DH) population (n = 267) was produced from hybrids of the cross LMPG-6S/Norin 40. The DH population segregated for a single gene (χ (1:1) (2) = 0.093, p = 0.76) for resistance to Puccinia graminis f.sp. tritici race LCBN. Four resistant DH lines were included in each of the 14 mini-bulks for screening. The Sr gene was successfully located to the long arm of chromosome 2D using MBSA. Further mapping confirmed the chromosome location and revealed that the Sr gene was located in a linkage block that may represent an alien

  10. Study on Stability of Sequential Extraction Method for Heavy Metal Speciations in Anoxic Sediments%缺氧沉积物中重金属形态连续萃取方法的稳定性研究

    Institute of Scientific and Technical Information of China (English)

    王畅; 夏冰; 王冠华; 宋玉梅; 吴凌涛; 郭鹏然

    2012-01-01

    Effects of the variations of pH value, temperature and colloidal particles in extractant solutions on heavy metals speciations were investigated by the sequential extraction procedure ( SEP) used in anoxic sediments at mariculture zone. The results showed that a slight increasement of pH values of extractant solutions lead to the decrease of concentrations of Cd and Zn in Stepl of SEP for acid soluble speciations, However, the obvious variations of pH values of extractant solutions had no significant influence on heavy metals speciations in Step2 for reducible fraction and Step3 for organic matter bound fraction ( except Pb) , respectively. The temperature of extractant solutions were slightly increased in Stepl and Step2 and decreased in Step3 due to the different reaction thermodynamics in extraction steps of SEP, and the variations of temperature( <2. 5) had little effects on the concentrations of heavy metals speciations. Due to adsorption, the formation of colloid in Stepl, Step2 and Step4 resulted in the decrease of Cd, Zn and Cu concentrations, respectively. However, the formation of colloid was controlled by extractant in Step3. Therefore, controlling pH and colloid in extractant solutions were available to improve the stability and accuracy of extraction results when SEP was applied to evaluate heavy metals speciations in anoxic sediments.%考察了海水养殖区域缺氧沉积物中重金属形态连续萃取法萃取过程中溶液pH值、温度变化和胶体形成对形态分离结果的影响.结果表明,连续萃取法Step1萃取酸溶态时,萃取液pH值的轻微升高使Pb和Zn的萃取结果明显降低;Step2萃取还原态时,萃取液pH值明显升高对重金属的萃取结果影响很小;Step3萃取有机质结合态时,萃取液pH值的降低对重金属萃取结果影响较小(除Pb外).由于连续萃取法中各步萃取反应的热力学过程不同,Step1和Step2萃取后溶液温度轻微升高而在Step3中溶液温度稍

  11. Speciation by Symbiosis: the Microbiome and Behavior.

    Science.gov (United States)

    Shropshire, J Dylan; Bordenstein, Seth R

    2016-01-01

    Species are fundamental units of comparison in biology. The newly discovered importance and ubiquity of host-associated microorganisms are now stimulating work on the roles that microbes can play in animal speciation. We previously synthesized the literature and advanced concepts of speciation by symbiosis with notable attention to hybrid sterility and lethality. Here, we review recent studies and relevant data on microbes as players in host behavior and behavioral isolation, emphasizing the patterns seen in these analyses and highlighting areas worthy of additional exploration. We conclude that the role of microbial symbionts in behavior and speciation is gaining exciting traction and that the holobiont and hologenome concepts afford an evolving intellectual framework to promote research and intellectual exchange between disciplines such as behavior, microbiology, genetics, symbiosis, and speciation. Given the increasing centrality of microbiology in macroscopic life, microbial symbiosis is arguably the most neglected aspect of animal and plant speciation, and studying it should yield a better understanding of the origin of species. PMID:27034284

  12. How Facilitation May Interfere with Ecological Speciation

    Directory of Open Access Journals (Sweden)

    P. Liancourt

    2012-01-01

    Full Text Available Compared to the vast literature linking competitive interactions and speciation, attempts to understand the role of facilitation for evolutionary diversification remain scarce. Yet, community ecologists now recognize the importance of positive interactions within plant communities. Here, we examine how facilitation may interfere with the mechanisms of ecological speciation. We argue that facilitation is likely to (1 maintain gene flow among incipient species by enabling cooccurrence of adapted and maladapted forms in marginal habitats and (2 increase fitness of introgressed forms and limit reinforcement in secondary contact zones. Alternatively, we present how facilitation may favour colonization of marginal habitats and thus enhance local adaptation and ecological speciation. Therefore, facilitation may impede or pave the way for ecological speciation. Using a simple spatially and genetically explicit modelling framework, we illustrate and propose some first testable ideas about how, when, and where facilitation may act as a cohesive force for ecological speciation. These hypotheses and the modelling framework proposed should stimulate further empirical and theoretical research examining the role of both competitive and positive interactions in the formation of incipient species.

  13. Speciation and interfacial studies using electrochemical techniques for nuclear applications

    International Nuclear Information System (INIS)

    In this the electrochemical techniques for speciation studies and some of the results on speciation of copper in the presence of a few volatile amines which are potential candidates for AVT are discussed

  14. Arsenic speciation in humans and food products: a review.

    Science.gov (United States)

    Benramdane, L; Bressolle, F; Vallon, J J

    1999-09-01

    Although acute intoxication has become rare, arsenic (As) is still a dangerous pollution agent for industrial workers and people living in the vicinity of emission sources. In humans, only inorganic As is toxic; organic forms present in large amounts in the environment are nontoxic. It is therefore important to be able to differentiate one group from the other using appropriate speciation methods. The authors review the present knowledge of the distribution of As in humans and food products. The three steps of the speciation methods (sample preparation, species separation, and detection) are described. For liquid samples, a clean-up step (C18 cartridge extraction, dilution, or freezing) is necessary to eliminate proteins and salts from the matrix. For solid organic samples, the first step consists of the digestion of tissues followed by solvent extraction sometimes coupled with a C18 extraction. The separation of As species is accomplished by different high-performance liquid chromatography (HPLC) methods (ion-exchange, ion-pairing, and micellar liquid chromatography). The detection methods are compatible with HPLC and are able to detect As species in the microgram-per-liter range. Inductively coupled plasma (ICP) atomic emission spectrometry is more frequently used, but suffers from interference by organic solvents in the mobile phases. Atomic absorption spectrometry methods give sensitivities of the same order. ICP-mass spectrometry has the advantage of specificity and can be 100- to 1000-fold more sensitive than previous methods. PMID:10497786

  15. Laser-Based Spectroscopic Study on the Speciation of U(VI)-OH Complexes in Aqueous Media

    International Nuclear Information System (INIS)

    Chemical speciation of actinides is fundamental for improving our understanding of their behavior under natural aquatic conditions for the safety assessment of a nuclear waste disposal. In past decades, a number of spectroscopic techniques were developed for the direct speciation of ionic actinide species (hydrated metal ions, hydrolyzed ions and binary or ternary complexes) in an aqueous phase. Conventional absorption spectroscopy by using a UV/VIS spectrophotometer is a useful method for a speciation and most researchers are familiar with this method. But the poor detection sensitivity of a conventional UV/VIS spectrophotometer prevents the speciation of actinides in trace concentrations (-6 M). Therefore laser-based spectroscopic techniques with a much higher detection sensitivity, such as TRLIF (Time-Resolved Laser- Induced-Fluorescence) and LPAS (Laser Photo-acoustic Spectroscopy), have been developed in recent years

  16. Uranium speciation in Fernald soils

    International Nuclear Information System (INIS)

    This interim progress report describes new experimental data collected from October 1, 1992 through May 31, 1993 as part of the Characterization Task of the Uranium in Soils Integrated Demonstration of the Office of Technology Development, Office of Environmental Restoration and Waste Management of the United States Department of Energy. X-ray absorption and optical luminescence spectroscopies have been used to analyze the uranium remaining in contaminated soils from the Fernald site after these samples were treated by various decontamination technologies under development within this Integrated Demonstration. The treatment technologies included soil washes with carbonate, citrate, Tiron, and Tiron/dithionite mixtures. The effectiveness of these procedures is discussed in a separate report from the Decontamination Task group. The characterization results indicate that following the application of all of these treatment strategies the uranium remaining in the soil is still best characterized as being primarily in the hexavalent oxidation state. However, for the A-series soils from the Incinerator Area, the speciation of this remaining uranium is different than seen previously based on the x-ray absorption data. The luminescence data for these treated soils also demonstrate that there is a decrease in size and quantity of the particulate hexavalent uranium that gives rise to the structured green emission. Thus, all treatment technologies do seem to generate a more dispersed, finer-grained form of uranium. For several treated samples a characteristic luminescence signal was found indicative of a schoepite phase of uranium. New results are also reported for untreated Fernald soil samples and reference uranium mineral phases

  17. Copper speciation in variably toxic sediments at the Ely Copper Mine, Vermont, United States

    Science.gov (United States)

    Kimball, Bryn E.; Foster, Andrea L.; Seal, Robert; Piatak, Nadine; Webb, Samuel M.; Hammarstrom, Jane M.

    2016-01-01

    At the Ely Copper Mine Superfund site, Cu concentrations exceed background values in both streamwater (160–1200 times) and sediments (15–79 times). Previously, these sediment samples were incubated with laboratory test organisms, and they exhibited variable toxicity for different stream sites. In this study we combined bulk- and microscale techniques to determine Cu speciation and distribution in these contaminated sediments on the basis of evidence from previous work that Cu was the most important stressor in this environment and that variable observed toxicity could have resulted from differences in Cu speciation. Copper speciation results were similar at microscopic and bulk scales. The major Cu species in the more toxic samples were sorbed or coprecipitated with secondary Mn (birnessite) and Fe minerals (jarosite and goethite), which together accounted for nearly 80% of the total Cu. The major Cu species in the less toxic samples were Cu sulfides (chalcopyrite and a covellite-like phase), making up about 80–95% of the total Cu, with minor amounts of Cu associated with jarosite or goethite. These Cu speciation results are consistent with the toxicity results, considering that Cu sorbed or coprecipitated with secondary phases at near-neutral pH is relatively less stable than Cu bound to sulfide at lower pH. The more toxic stream sediment sites were those that contained fewer detrital sulfides and were upstream of the major mine waste pile, suggesting that removal and consolidation of sulfide-bearing waste piles on site may not eliminate all sources of bioaccessible Cu.

  18. Copper Speciation in Variably Toxic Sediments at the Ely Copper Mine, Vermont, United States.

    Science.gov (United States)

    Kimball, Bryn E; Foster, Andrea L; Seal, Robert R; Piatak, Nadine M; Webb, Samuel M; Hammarstrom, Jane M

    2016-02-01

    At the Ely Copper Mine Superfund site, Cu concentrations exceed background values in both streamwater (160-1200 times) and sediments (15-79 times). Previously, these sediment samples were incubated with laboratory test organisms, and they exhibited variable toxicity for different stream sites. In this study we combined bulk- and microscale techniques to determine Cu speciation and distribution in these contaminated sediments on the basis of evidence from previous work that Cu was the most important stressor in this environment and that variable observed toxicity could have resulted from differences in Cu speciation. Copper speciation results were similar at microscopic and bulk scales. The major Cu species in the more toxic samples were sorbed or coprecipitated with secondary Mn (birnessite) and Fe minerals (jarosite and goethite), which together accounted for nearly 80% of the total Cu. The major Cu species in the less toxic samples were Cu sulfides (chalcopyrite and a covellite-like phase), making up about 80-95% of the total Cu, with minor amounts of Cu associated with jarosite or goethite. These Cu speciation results are consistent with the toxicity results, considering that Cu sorbed or coprecipitated with secondary phases at near-neutral pH is relatively less stable than Cu bound to sulfide at lower pH. The more toxic stream sediment sites were those that contained fewer detrital sulfides and were upstream of the major mine waste pile, suggesting that removal and consolidation of sulfide-bearing waste piles on site may not eliminate all sources of bioaccessible Cu. PMID:26734712

  19. Speciation of scandium and gallium in soil.

    Science.gov (United States)

    Połedniok, Justyna

    2008-09-01

    A method for the speciation of scandium and gallium in soil has been developed. The sequential extraction scheme of Tessier et al. for heavy metals was examined for the scandium and gallium separation. The regents proposed by Tessier were used for the extraction, and only for the residual fraction the HClO4 was replaced with H2SO4. The optimum conditions for leaching scandium and gallium from the soil were chosen for each fraction. Very sensitive, spectrophotometric methods based on the mixed complexes of Sc(III) and Ga(III) with Chrome Azurol S and benzyldodecyldimethylammonium bromide were applied for the scandium and gallium determination after their separation by solvent extraction. 100% mesityl oxide and a 0.5M solution of 2-thenoyltrifluoroacetone in xylene were chosen for the extraction of scandium and butyl acetate was selected for gallium. Soil samples from two different regions of Poland were the object of this research. The content of scandium and gallium found in the individual fractions of Upper Silesia soil (industrial region) was [in microgg(-1)] Sc: I, 1.52; II, 0.53; III, 7.78; IV, 1.79; V, 0.20; Ga: I, 24.7; III, 29.2; IV, 35.4; V, 6.9. In Podlasie soil (agricultural region), the content of both elements was clearly lower. The total content of scandium and gallium in the five soil fractions was in good correlation with the total content of these elements in the soils found after HF-H2SO4 digestion. Analysis using the ICP-OES method gave comparable results. PMID:18653213

  20. Implementation of speciation analysis in an accredited laboratory

    International Nuclear Information System (INIS)

    Full text: Due to successive introduction of speciation analysis in reglementary text or directives there is an increasing interest for elemental speciation. The implementation process of speciation analysis in a routine laboratory accredited according to ISO 17025 will be described with the example of methylmercury determination in biological samples with HPLC-ICPMS and HPLC-CV-ICPMS. Furthermore, the contribution of speciation analysis to answer questions relevant to environmental and health concerns will be presented. (author)

  1. Chemical speciation and bioavailability in radioecological research

    International Nuclear Information System (INIS)

    The science of radioecology in the framework of the CEC Radiation Protection Research Action is considered to serve to unravel the specific interaction between the ecosphere and the radioactivity as a chemical event, in order to deliver the reliable data for the dose calculation, to reveal the most sensitive eco-compartments (trophic level) in a foodchain, and to develop the skills needed in the technique of remedial actions, based onsound scientific principles. In this context speciation and bio-availability plays a more predominant role than originally envisaged. These parameters are however often not very well quantified or considered in the genuine context (ecosystem) were the changes in speciation or bio-availability occur. This paper is an attempt to elucidate some of the basic principles behind speciation and bio-availability. (orig.)

  2. Complex speciation of humans and chimpanzees.

    Science.gov (United States)

    Wakeley, John

    2008-03-13

    Genetic data from two or more species provide information about the process of speciation. In their analysis of DNA from humans, chimpanzees, gorillas, orangutans and macaques (HCGOM), Patterson et al. suggest that the apparently short divergence time between humans and chimpanzees on the X chromosome is explained by a massive interspecific hybridization event in the ancestry of these two species. However, Patterson et al. do not statistically test their own null model of simple speciation before concluding that speciation was complex, and--even if the null model could be rejected--they do not consider other explanations of a short divergence time on the X chromosome. These include natural selection on the X chromosome in the common ancestor of humans and chimpanzees, changes in the ratio of male-to-female mutation rates over time, and less extreme versions of divergence with gene flow (see ref. 2, for example). I therefore believe that their claim of hybridization is unwarranted. PMID:18337768

  3. SPECIATE Version 4.4 Database Development Documentation

    Science.gov (United States)

    SPECIATE is the U.S. Environmental Protection Agency’s (EPA) repository of volatile organic gas and particulate matter (PM) speciation profiles of air pollution sources. Some of the many uses of these source profiles include: (1) creating speciated emissions inventories for regi...

  4. Coulombic Fluids Bulk and Interfaces

    CERN Document Server

    Freyland, Werner

    2011-01-01

    Ionic liquids have attracted considerable interest in recent years. In this book the bulk and interfacial physico-chemical characteristics of various fluid systems dominated by Coulomb interactions are treated which includes molten salts, ionic liquids as well as metal-molten salt mixtures and expanded fluid metals. Of particular interest is the comparison of the different systems. Topics in the bulk phase concern the microscopic structure, the phase behaviour and critical phenomena, and the metal-nonmetal transition. Interfacial phenomena include wetting transitions, electrowetting, surface freezing, and the electrified ionic liquid/ electrode interface. With regard to the latter 2D and 3D electrochemical phase formation of metals and semi-conductors on the nanometer scale is described for a number of selected examples. The basic concepts and various experimental methods are introduced making the book suitable for both graduate students and researchers interested in Coulombic fluids.

  5. Hydrogen speciation in hydrated layers on nuclear waste glass

    International Nuclear Information System (INIS)

    The hydration of an outer layer on nuclear waste glasses is known to occur during leaching, but the actual speciation of hydrogen (as water or hydroxyl groups) in these layers has not been determined. As part of the Nevada Nuclear Waste Storage Investigations Project, we have used infrared spectroscopy to determine hydrogen speciations in three nuclear waste glass compositions (SRL-131 and 165, and PNL 76-68), which were leached at 900C (all glasses) or hydrated in a vapor-saturated atmosphere at 2020C (SRL-131 only). Hydroxyl groups were found in the surface layers of all the glasses. Molecular water was found in the surface of SRL-131 and PNL 76-68 glasses that had been leached for several months in deionized water, and in the vapor-hydrated sample. The water/hydroxyl ratio increases with increasing reaction time; molecular water makes up most of the hydrogen in the thick reaction layers on vapor-phase hydrated glass while only hydroxyl occurs in the least reacted samples. Using the known molar absorptivities of water and hydroxyl in silica-rich glass the vapor-phase layer contained 4.8 moles/liter of molecular water, and 0.6 moles water in the form hydroxyl. A 15 μm layer on SRL-131 glass formed by leaching at 900C contained a total of 4.9 moles/liter of water, 2/3 of which was as hydroxyl. The unreacted bulk glass contains about 0.018 moles/liter water, all as hydroxyl. The amount of hydrogen added to the SRL-131 glass was about 70% of the original Na + Li content, not the 300% that would result from alkali=hydronium ion interdiffusion. If all the hydrogen is then assumed to be added as the result of alkali-H+ interdiffusion, the molecular water observed may have formed from condensation of the original hydroxyl groups

  6. Bulk chemicals from biomass

    NARCIS (Netherlands)

    Haveren, van J.; Scott, E.L.; Sanders, J.P.M.

    2008-01-01

    Given the current robust forces driving sustainable production, and available biomass conversion technologies, biomass-based routes are expected to make a significant impact on the production of bulk chemicals within 10 years, and a huge impact within 20-30 years. In the Port of Rotterdam there is a

  7. Ferromagnetic bulk glassy alloys

    International Nuclear Information System (INIS)

    This paper deals with the review on the formation, thermal stability and magnetic properties of the Fe-based bulk glassy alloys in as-cast bulk and melt-spun ribbon forms. A large supercooled liquid region over 50 K before crystallization was obtained in Fe-(Al, Ga)-(P, C, B, Si), Fe-(Cr, Mo, Nb)-(Al, Ga)-(P, C, B) and (Fe, Co, Ni)-Zr-M-B (M=Ti, Hf, V, Nb, Ta, Cr, Mo and W) systems and bulk glassy alloys were produced in a thickness range below 2 mm for the Fe-(Al, Ga)-(P, C, B, Si) system and 6 mm for the Fe-Co-(Zr, Nb, Ta)-(Mo, W)-B system by copper-mold casting. The ring-shaped glassy Fe-(Al, Ga)-(P, C, B, Si) alloys exhibit much better soft magnetic properties as compared with the ring-shaped alloy made from the melt-spun ribbon because of the formation of the unique domain structure. The good combination of high glass-forming ability and good soft magnetic properties indicates the possibility of future development as a new bulk glassy magnetic material

  8. Heat transport in bulk/nanoporous/bulk silicon devices

    Energy Technology Data Exchange (ETDEWEB)

    Criado-Sancho, M. [Departamento de Ciencias y Técnicas Físicoquimicas, Facultad de Ciencias, UNED, Senda del Rey 9, 20040 Madrid (Spain); Jou, D., E-mail: David.Jou@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain)

    2013-02-04

    We study heat transport in bulk/nanoporous/bulk silicon devices; we show that, despite bulk/nanoporous devices may act as thermal rectifiers, the non-linear aspects of their joint thermal conductance are not strong enough to lead to a negative differential thermal resistance, necessary to allow bulk/nanoporous/bulk Si devices to act as thermal transistors. Furthermore, we explicitly study the effective thermal conductivity of the mentioned devices for several temperatures, geometries, porosities, and pore size.

  9. Analytical developments in ICP-MS for arsenic and selenium speciation. Application to granitic waters

    International Nuclear Information System (INIS)

    Nuclear waste storage in geological areas needs the understanding of the physico-chemistry of groundwaters interactions with surrounding rocks. Redox potential measurements and speciation, calculated from geochemical modelling are not significant for the determination of water reactivity. We have thus chosen to carry out experimental speciation by developing sensitive analytical tools with respect of specie chemical identity. We have studied two redox indicators from reference sites (thermal waters from Pyrenees, France): arsenic and selenium. At first, we have determined the concentrations in major ions (sulphide, sulphate, chloride, fluoride, carbonate, Na, K, Ca). Speciation was conducted by HPLC hyphenated to quadrupole ICP-MS and high resolution ICP-MS. These analyses have shown the presence of two new arsenic species in solution, in addition of a great reactivity of these waters during stability studies. A sampling, storage and analysis method is described. (author)

  10. Factors Controlling Redox Speciation of Plutonium and Neptunium in Extraction Separation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Paulenova, Alena [Principal Investigator; Vandegrift, III, George F. [Collaborator

    2013-09-24

    The objective of the project was to examine the factors controlling redox speciation of plutonium and neptunium in UREX+ extraction in terms of redox potentials, redox mechanism, kinetics and thermodynamics. Researchers employed redox-speciation extractions schemes in parallel to the spectroscopic experiments. The resulting distribution of redox species w studied uring spectroscopic, electrochemical, and spectro-electrochemical methods. This work reulted in collection of data on redox stability and distribution of redox couples in the nitric acid/nitrate electrolyte and the development of redox buffers to stabilize the desired oxidation state of separated radionuclides. The effects of temperature and concentrations on the redox behavior of neptunium were evaluated.

  11. Changes in Zinc Speciation with Mine Tailings Acidification in a Semiarid Weathering Environment

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon (UCM); (SLAC); (Ariz)

    2012-10-09

    High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semiarid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6000 to 450 mg kg{sup -1}) and plant-available (590 to 75 mg kg{sup -1}) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and microfocused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn{sub 0.8}talc), Zn sorbed to ferrihydrite (Zn{sub adsFeOx}), and zinc sulfate (ZnSO{sub 4} {center_dot} 7H{sub 2}O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Microscale analyses identified hetaerolite (ZnMn{sub 2}O{sub 4}), hemimorphite (Zn{sub 4}Si{sub 2}O{sub 7}(OH){sub 2} {center_dot} H{sub 2}O) and sphalerite (ZnS) as minor phases. Bulk and microfocused spectroscopy complement the chemical extraction results and highlight the importance of using a multimethod approach to interrogate complex tailings systems.

  12. Biosensor for metal analysis and speciation

    Science.gov (United States)

    Aiken, Abigail M.; Peyton, Brent M.; Apel, William A.; Petersen, James N.

    2007-01-30

    A biosensor for metal analysis and speciation is disclosed. The biosensor comprises an electron carrier immobilized to a surface of an electrode and a layer of an immobilized enzyme adjacent to the electrode. The immobilized enzyme comprises an enzyme having biological activity inhibited by a metal to be detected by the biosensor.

  13. Breeding resource specialization and speciation in fishes

    Czech Academy of Sciences Publication Activity Database

    Reichard, Martin; Kitamura, J.; Smith, C.

    Berlin: Leibnitz-Institute of Freshwater Ecology and Inland Fisheries, 2009. s. 69. [International Conference on Evolutionary Ecology of Fishes Diversification, Adaptation and Speciation. 23.11.2009-25.11.2009, Berlin] R&D Projects: GA AV ČR KJB600930802 Institutional research plan: CEZ:AV0Z60930519 Keywords : fish reproduction Subject RIV: EH - Ecology, Behaviour

  14. EFFECT OF SCR CATALYST ON MERCURY SPECIATION

    Science.gov (United States)

    A pilot-scale research study was conducted to investigate the effect of selective catalytic reduction (SCR) on elemental mercury speciation in bituminous and subbituminous coal combustion flue gases. Three different Illinois bituminous coals and one Powder River Basin (PRB) coal...

  15. Behavioural reproductive isolation and speciation in Drosophila

    Indian Academy of Sciences (India)

    Punita Nanda; Bashisth Narayan Singh

    2012-06-01

    The origin of premating reproductive isolation continues to help elucidate the process of speciation and is the central event in the evolution of biological species. Therefore, during the process of species formation the diverging populations must acquire some means of reproductive isolation so that the genes from one gene pool are prevented from dispersing freely into a foreign gene pool. In the genus Drosophila, the phenomenon of behavioural reproductive isolation, which is an important type of premating (prezygotic) reproductive isolating mechanisms, has been extensively studied and interesting data have been documented. In many cases incomplete sexual isolation has been observed and the pattern and degree of isolation within and between the species have often been used to elucidate the phylogenetic relationships. The present review documents an overview of speciation mediated through behavioural incompatibility in different species groups of Drosophila with particular reference to the models proposed on the basis of one-sided ethological isolation to predict the direction of evolution. This study is crucial for understanding the mechanism of speciation through behavioural incompatibility and also for an understanding of speciation genetics in future prospects.

  16. Characterization of Technetium Speciation in Cast Stone

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Wang, Guohui; Westsik, Joseph H.; Peterson, Reid A.

    2013-11-11

    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Production and Long-Term Performance of Low Temperature Waste Forms” to provide additional information on technetium (Tc) speciation characterization in the Cast Stone waste form. To support the use of Cast Stone as an alternative to vitrification for solidifying low-activity waste (LAW) and as the current baseline waste form for secondary waste streams at the Hanford Site, additional understanding of Tc speciation in Cast Stone is needed to predict the long-term Tc leachability from Cast Stone and to meet the regulatory disposal-facility performance requirements for the Integrated Disposal Facility (IDF). Characterizations of the Tc speciation within the Cast Stone after leaching under various conditions provide insights into how the Tc is retained and released. The data generated by the laboratory tests described in this report provide both empirical and more scientific information to increase our understanding of Tc speciation in Cast Stone and its release mechanism under relevant leaching processes for the purpose of filling data gaps and to support the long-term risk and performance assessments of Cast Stone in the IDF at the Hanford Site.

  17. Electrochemical metal speciation in colloidal dispersions.

    NARCIS (Netherlands)

    Wonders, J.H.A.M.

    1995-01-01

    The term "heavy metals" is connected with toxicity. They form strong complexes with enzymes, other proteins and DNA in living organisms, which causes dysfunctioning and hence poisoning. In combination with the uptake mechanism of the organism, speciation of heavy metal determines the bio-availabilit

  18. Speciation of arsenic in environmental waters

    International Nuclear Information System (INIS)

    A system for speciation of arsenic in environmental waters by selective hydride formation and on-line AAS is described. Starting from literature data, the separation scheme and the necessary apparatus are outlined. Preliminary practical experience then leads to the formulation of further improvements and accompanying testing experiments. (author). 51 refs, 7 figs, 1 tab

  19. Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

    Directory of Open Access Journals (Sweden)

    Hugh H. Harris

    2013-05-01

    Full Text Available Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS and X-ray fluorescence microscopy (XFM. The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed.

  20. Soft magnetic properties and thermal stability of bulk Fe83B17 alloy prepared by undercooling and Cu-mold casting methods

    International Nuclear Information System (INIS)

    The thermal stability and soft magnetic properties of bulk Fe83B17 rods with nano-lamellar eutectic structures and metastable Fe3B phases were investigated by annealing at 973–1273 K for 1.5 h. Samples with a diameter of 3 mm were prepared by undercooling solidification combined with Cu-mold casting. The decomposition of Fe3B and the transformation of nano-lamellar eutectic structures were finished after annealing at 1173 K for 1.5 h. Increasing annealing temperature showed that the soft magnetic properties of the sample were kept relatively stable. The saturation magnetization and retentivity were decreased only slightly, while the coercivity was decreased significantly. - Highlights: • Thermal stability of the nano-lamellar eutectic structure was obtained. • Thermal stability of the metastable Fe3B phase was obtained. • The soft magnetic properties of the sample remain stability by annealing. • Nano-lamellar eutectic structures enhance the soft magnetic properties

  1. Bulk Diffusion via a ``kick-out'' method for Lithium in the decomposition reaction LiAlH4/Li3AlH6

    Science.gov (United States)

    Rolih, Biljana; Ozolins, Vidvuds; Ozolins Team

    2013-03-01

    In the pursuit to find a practical system for hydrogen storage, complex metal hydrides have long been considered as viable candidates due to their high hydrogen content. However, some of the challenges faced with these types of systems are poor thermodynamics or kinetics. The underlying mechanisms, and their limiting processes, for the decomposition of these materials need to be understood. From experimental work on the decomposition of hydrogen storage materials, it has been suggested that bulk diffusion of metal species is the bottleneck for hydrogen release. In this work is the dehydrogenation we investigated the system LiAlH4  LiAlH6 with favorable hydrogen release (5.3 wt %), at moderate temperatures. Using first-principles density functional theory we found the defects facilitating mass transport by calculating individual formation energies, highest concentrations, and activation barriers for defect mobility. The mass transport of Lithium is found to be mediated by a ``kick-out'' mechanism. The results are used to further our understanding of the fundamental mechanism of mass transport and evaluate the possibility of kinetics as the limiting process in this reaction.

  2. Speciation of actinides in aqueous solution by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    International Nuclear Information System (INIS)

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) as a sensitive and selective method has been applied to the speciation of actinides in aqueous solution. Studies on hydrolysis and carbonate complexation of U(VI) and on determination of hydration number of Cm(III) are reported. (author)

  3. Introduction to the EU-network on trace element speciation: preparing for the 21(st) century

    DEFF Research Database (Denmark)

    Cornelis, R.; Camara, C.; Ebdon, L.; Pitts, L.; Welz, B.; Morabito, R.; Donard, O.; Crews, H.; Larsen, Erik Huusfeldt; Neidhart, B.; Ariese, F.; Rosenberg, E.; Mathe, D.; Morrison, G. M.; Cordier, G.; Adams, F.; van Doren, P.; Marshall, J.; Stojanik, B.; Ekvall, A.; Quevauviller, P.

    The main objective of the EU-network is to bring together scientists with a background in analytical chemistry interested in speciation method development with potential users from industry and representatives from legislative bodies. The network started on 1/10/1997 for a duration of 2 years. A ...

  4. Bulk materials handling review

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-02-15

    The paper provides details of some of the most important coal handling projects and technologies worldwide. It describes development by Aubema Crushing Technology GmbH, Bedeschi, Cimbria Moduflex, DBT, Dynamic Air Conveying Systems, E & F Services, InBulk Technologies, Nord-Sen Metal Industries Ltd., Pebco Inc, Primasonics International Ltd., R.J.S. Silo Clean (International) Ltd., Takraf GmbH, and The ACT Group. 17 photos.

  5. Speciation of aluminum in aqueous solutions using ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Bertsch, P.M.; Anderson, M.A.

    1989-03-15

    An ion chromatographic method in which aluminum (AI) is quantitatively determined via postcolumn derivatization with Tiron (4,5-dihydroxy-m-benzenedisulfonic acid) was evaluated for its utility as a method for speciating AI in aqueous solutions. Fluro-, oxalato-, and citratoaluminum complexes were identified by distinct peaks within chromatograms of AI solutions when the appropriate ligand was added. Excellent quantitative agreement between predicted species concentrations (via the thermodynamic speciation model GEOCHEM) and those determined by ion chromatography was obtained for samples prepared in the eluent matrix. The predominantly outer sphere sulfatoaluminum complexes were not observed to elute as singly charged species, but rather exhibited a retention time indistinguishable from the AI(H/sub 2/O)6(3+) species. It is concluded that inner sphere AI complexes (generally possessing relatively high association constants) possess adequate kinetic stability to withstand degradation during the ion exchange process, whereas outer sphere complexes apparently readily dissociate in the presence of the sulfonate exchange sites. Deviations in sample ionic strength (mu) and pH from that of the eluent resulted in some redistribution among species, the degree of which was ligand specific.

  6. Extraction-Free Ion-Pair Methods for the Assay of Trifluoperazine Dihydrochloride in Bulk Drug, Tablets, and Spiked Human Urine Using Three Sulfonphthalein Dyes

    Science.gov (United States)

    Prashanth, K. N.; Swamy, N.; Basavaiah, K.

    2014-11-01

    Three simple and sensitive extraction-free spectrophotometric methods are described for the determination of trifluoperazine dihydrochloride (TFH). The methods are based on ion pair complex formation between the nitrogenous compound trifluoperazine (TFP) converted from trifluoperazine dihydrochloride and sulfonphthalein dyes, namely, bromocresol green (BCG), bromothymol blue (BTB), and bromophenol blue (BPB) in dichloromethane medium in which all the above experimental variables were circumvented. The colored products are measured at 425 nm in the BCG method, 415 nm in the BTB method, and 420 nm in the BPB method. The stoichiometry of the ion-pair complexes formed between the drug and dye (1:1) was determined by Job's continuous variations method, and the stability constants of the complexes were also calculated. These methods quantify TFP over the concentration ranges of 1.25-20.0 μg/ml in the BCG method, 1.5-21.0 μg/ml in the BTB method, and 1.5-18.0 μg/ml in the BPB method. The molar absorptivity (l·mol-1·cm-1) and Sandell sensitivity (ng/cm2) were calculated to be 2.06·104 and 0.0197; 1.82·104 and 0.0224; and 2.22·104 and 0.0183 for the BCG, BTB, and BPB methods, respectively. The methods were successfully applied to the determination of TFP in pure drug, pharmaceuticals, and in spiked human urine with good accuracy and precision.

  7. Speciation of arsenic trioxide metabolites in peripheral blood and bone marrow from an acute promyelocytic leukemia patient

    Directory of Open Access Journals (Sweden)

    Iriyama Noriyoshi

    2012-01-01

    Full Text Available Abstract Background Speciation of arsenic trioxide (ATO metabolites in clinical samples such as peripheral blood (PB from acute promyelocytic leukemia (APL patients has been conducted. However, speciation of arsenicals in bone marrow (BM has not yet been performed. Profiles of arsenic speciation in plasma of BM were thus investigated and compared with those of PB plasma from a relapsed APL patient. The total arsenic concentrations in high molecular weight fraction (HMW-F of BM and PB plasma were also determined. Methods Response assessment was evaluated by BM aspirate examination and fluorescence in situ hybridization analysis. The analyses of total arsenic concentrations and speciation were preformed by inductively coupled plasma mass spectrometry (ICP-MS, and high-performance liquid chromatography (HPLC/ICP-MS, respectively. Results Response assessment showed that the patient achieved complete remission. The total arsenic concentrations in BM plasma increased with time during the consecutive administration. The PB plasma concentrations of methylated arsenic metabolites substantially increased after the start of administration, while those of inorganic arsenic were still kept at a low level, followed by substantially increase from day-14 after administration. The arsenic speciation profiles of PB plasma were very similar to those of BM plasma. Furthermore, the total arsenic concentrations of HMW-F in BM plasma were much higher than those in PB plasma. Conclusions The behaviors of arsenic speciation suggested for the first time that arsenic speciation analysis of PB plasma could be predicative for BM speciation, and showed relatively higher efficiency of drug metabolism in the patient. These results may further provide not only significance of clinical application of ATO, but also a new insight into host defense mechanisms in APL patients undergoing ATO treatment, since HMW proteins-bound arsenic complex could be thought to protect BM from the

  8. Contribution of analytical techniques coupled to the knowledge of the uranium speciation in natural conditions

    International Nuclear Information System (INIS)

    To understand the transport mechanisms and the radionuclides behaviour in the bio-geosphere is necessary to evaluate healthy and environmental risks of nuclear industry. These mechanisms are monitored by radioelements speciation, namely the distribution between their different physico-chemical forms in the environment. From this perspective, this PhD thesis deals with uranium speciation in a natural background. A detailed summary of uranium biogeochemistry has been written, which enables to restrict the PhD issue to uranium complexation with oxalic acid, a hydrophilic organic acid with good binding properties, ubiquitous in soil waters. Analytical conditions have been established by means of speciation diagrams. The speciation diagrams building by means of literature stability constants has allowed to define the analytical conditions of complex formation. The chosen analytical technique is the hyphenation of a separative technique (liquid chromatography LC or capillary electrophoresis CE) with mass spectrometry (ICPMS). The studied complexes presence in the synthetic samples has been confirmed with UV/visible spectrophotometry. LC-ICPMS analyses have proved the lability of the uranyl-organic acid complexes, namely their tendency to dissociate during analysis, which prevents from studying uranium speciation. CE-ICPMS study of labile complexes from a metal-ligand system has been made possible by employing affinity capillary electrophoresis, which enables to determine stability constants and electrophoretic mobilities. This PhD thesis has allowed to compare the different mathematical treatments of binding isotherm and to take into account ionic strength and real ligand concentration. Affinity CE has been applied successfully to lanthanum-oxalate (model system) and uranium-oxalate systems. The obtained results have been applied to a real system (situated in Le Bouchet). This shows the contribution of the developed method to the modelling of uranium speciation. (author)

  9. Speciation neutron activation analysis for arsenic in marine fish

    International Nuclear Information System (INIS)

    Neutron activation analysis (NAA) methods involving chemical separations prior to irradiations can be developed to determine the species of an element. The technique can be called speciation NAA (SNAA). We have developed SNAA methods for assaying various arsenic species, namely As(III), As(V), dimethyl arsonic acid (DMA), monomethylarsinic acid (MMA), arsenobetaine (AsB), organically bound arsenic (OBAs), and lipid-soluble arsenic (LSAs) in marine fish samples. The method involves extraction by a methanol-MIBK-water system, cation exchange chromatography, and HPLC followed by NAA. The detection limits for various arsenic species are around 20 ng g-1 of fish under the experimental conditions of 2-h irradiation in a neutron flux of 5x1011 cm-2 s-1 at the Dalhousie University SLOWPOKE-2 facility. Details of the methods and results are presented

  10. Microextraction techniques for the non-chromatographic speciation of ultratraces of elements in waters: some significant cases

    Science.gov (United States)

    Lopez-Garcia, Ignacio; Vicente-Martinez, Yesica; Hernandez-Cordoba, Manuel; Martínez-Sanchez, Maria Jose; Perez-Sirvent, Carmen

    2015-04-01

    The speciation of very low concentrations of some elements in waters is of interest due to the different behaviour and toxicity the species can have. This task can be carried out by using liquid chromatographic techniques (LC) for separation together with inductively coupled plasma mass spectrometry (ICP-MS) for detection. However, this combination is not easily available in all laboratories mainly due to the relative high cost of acquisition and maintenance of the ICP-MS spectrometer, and so other alternatives are of practical interest. Present knowledge of microextraction techniques involving minimal (or none) amounts of organic solvents allows, in some cases, speciation to be carried out without the need of such an expensive instrument, and even avoiding the use of a chromatographic stage. The selectivity of the separation (fractionation or speciation) can be achieved by modifying the experimental conditions used for microextraction, and a sensitive final measurement be obtained by means of electrothermal atomic absorption spectrometry (ETAAS). In this way, since an ETAAS instrument is common (and sometimes underused) in all laboratories, the speciation procedures are made available to most laboratories worldwide. The high preconcentration factor achieved by means of the microextraction stage together with the high sensitivity inherent in ETAAS measurements result in extremely sensitive methods that permit the speciation at ultratrace levels. The advantages of this methodology are presented by discussing speciation of chromium and arsenic as representative examples.

  11. Iron - based bulk amorphous alloys

    Directory of Open Access Journals (Sweden)

    R. Babilas

    2010-07-01

    Full Text Available Purpose: The paper presents a structure characterization, thermal and soft magnetic properties analysis of Fe-based bulk amorphous materials in as-cast state and after crystallization process. In addition, the paper gives some brief review about achieving, formation and structure of bulk metallic glasses as a special group of amorphous materials.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA and differential scanning calorimetry (DSC. The magnetic properties contained initial and maximum magnetic permeability, coercive force and magnetic after-effects measurements were determined by the Maxwell-Wien bridge and VSM methods.Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast bulk metallic glasses in form of ribbons and rods were amorphous. Two stage crystallization process was observed for studied bulk amorphous alloy. The differences of crystallization temperature between ribbons and rods with chosen thickness are probably caused by different amorphous structures as a result of the different cooling rates in casting process. The SEM images showed that studied fractures could be classified as mixed fractures with indicated two zones contained “river” and “smooth” areas. The changing of chosen soft magnetic properties (μr, Bs, Hc obtained for samples with different thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The annealing process in temperature range from 373 to 773 K causes structural relaxation of tested amorphous materials, which leads to changes in their physical properties. The qualitative

  12. Foliar or root exposures to smelter particles: Consequences for lead compartmentalization and speciation in plant leaves

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, Eva [Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet-Tolosan (France); CNRS, EcoLab, 31326 Castanet-Tolosan (France); Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse (France); Dappe, Vincent [LASIR (UMR CNRS 8516), Université de Lille 1, Bât. C5, 59655 Villeneuve d' Ascq Cedex (France); Sarret, Géraldine [ISTerre, UMR 5275, Université Grenoble I, CNRS, F-38041 Grenoble (France); Sobanska, Sophie [LASIR (UMR CNRS 8516), Université de Lille 1, Bât. C5, 59655 Villeneuve d' Ascq Cedex (France); Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna [Department of Chemistry, John Paul II Catholic University of Lublin, Al. Kraśnicka 102, 20-718 Lublin (Poland); Magnin, Valérie [ISTerre, UMR 5275, Université Grenoble I, CNRS, F-38041 Grenoble (France); Ranieri, Vincent [CEA-INAC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Dumat, Camille, E-mail: camille.dumat@ensat.fr [Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet-Tolosan (France); CNRS, EcoLab, 31326 Castanet-Tolosan (France)

    2014-04-01

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO{sub 4}, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO{sub 3}. In rye-grass, the changes in Pb speciation were even more egregious: Pb–cell wall and Pb–organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to

  13. Foliar or root exposures to smelter particles: Consequences for lead compartmentalization and speciation in plant leaves

    International Nuclear Information System (INIS)

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO4, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO3. In rye-grass, the changes in Pb speciation were even more egregious: Pb–cell wall and Pb–organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better assess

  14. Foliar or root exposures to smelter particles: consequences for lead compartmentalization and speciation in plant leaves.

    Science.gov (United States)

    Schreck, Eva; Dappe, Vincent; Sarret, Géraldine; Sobanska, Sophie; Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna; Magnin, Valérie; Ranieri, Vincent; Dumat, Camille

    2014-04-01

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO4, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO3. In rye-grass, the changes in Pb speciation were even more egregious: Pb-cell wall and Pb-organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better assess the

  15. Evaluation of DGT as a metal speciation tool in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Buzier, Remy [Cemagref, UR Hydrosystemes et Bioprocedes, parc de Tourvoie, BP 44, 92163 Antony Cedex (France); Tusseau-Vuillemin, Marie-Helene [Cemagref, UR Hydrosystemes et Bioprocedes, parc de Tourvoie, BP 44, 92163 Antony Cedex (France)]. E-mail: marie-helene.tusseau@cemagref.fr; Mouchel, Jean-Marie [Centre d' Enseignement et de Recherche Eau Ville Environnement, ENPC, cite Descartes, 77455 Marne la Vallee Cedex 02 (France)

    2006-04-01

    This paper aims to evaluate the performance of the diffusive gradient in thin film technique (DGT) as a speciation tool for metals in wastewater. The validity of metal sampling by DGT in wastewater was checked. DGT was used in parallel with the Daphnia magna acute toxicity test in order to obtain information on the speciation of copper and cadmium in diluted and spiked filtered wastewater (raw and treated) from two treatment plants. Combining the chemical (DGT) and the biological methods (D. magna toxicity test) allowed metal to be fractionated into inorganic, labile organic and inert organic metal. Copper was mainly found as inert organic complexes, whereas the major part of cadmium was found to be labile organic complexes. The proportion of inert organic copper complexes was higher in the presence of treated wastewater than in raw wastewater. The use of restricted gels in DGT devices discriminated more labile organic cadmium than labile organic copper, indicating that cadmium weak ligands have more complex structures than copper weak ligands. In our experimental conditions (i.e. a high metal to ligand ratio), DGT, even equipped with restricted gels, was able to accumulate labile organic complexes. This result highlights that the ecotoxicological interpretation of DGT measurement should be considered carefully. DGT is a reliable tool to assess the chemical characteristics of metals (i.e. reactivity) in wastewater, but it does not ensure that only inorganic metal is measured.

  16. Evaluation of DGT as a metal speciation tool in wastewater

    International Nuclear Information System (INIS)

    This paper aims to evaluate the performance of the diffusive gradient in thin film technique (DGT) as a speciation tool for metals in wastewater. The validity of metal sampling by DGT in wastewater was checked. DGT was used in parallel with the Daphnia magna acute toxicity test in order to obtain information on the speciation of copper and cadmium in diluted and spiked filtered wastewater (raw and treated) from two treatment plants. Combining the chemical (DGT) and the biological methods (D. magna toxicity test) allowed metal to be fractionated into inorganic, labile organic and inert organic metal. Copper was mainly found as inert organic complexes, whereas the major part of cadmium was found to be labile organic complexes. The proportion of inert organic copper complexes was higher in the presence of treated wastewater than in raw wastewater. The use of restricted gels in DGT devices discriminated more labile organic cadmium than labile organic copper, indicating that cadmium weak ligands have more complex structures than copper weak ligands. In our experimental conditions (i.e. a high metal to ligand ratio), DGT, even equipped with restricted gels, was able to accumulate labile organic complexes. This result highlights that the ecotoxicological interpretation of DGT measurement should be considered carefully. DGT is a reliable tool to assess the chemical characteristics of metals (i.e. reactivity) in wastewater, but it does not ensure that only inorganic metal is measured

  17. Bulk growth of <001> organic nonlinear optical (NLO) L-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) single crystals by SR method

    Energy Technology Data Exchange (ETDEWEB)

    Pandian, Muthu Senthil, E-mail: senthilpandianm@ssn.edu.in; Sivasubramani, V.; Ramasamy, P. [SSN Research Centre, SSN College of Engineering, Kalavakkam-603110, Tamilnadu (India)

    2015-06-24

    A transparent uniaxial L-arginine 4-nitrophenolate 4-nitrophenol dehydrate (LAPP) single crystal having dimension of 20 mm diameter and 45 mm length was grown by Sankaranarayanan-Ramasamy (SR) method with a growth rate of 1 mm per day. Using an identical solution the conventional crystal grown to a dimension of 8×5×5 mm{sup 3} was obtained over a period of 30 days. The crystal structure has been confirmed by single crystal X-ray diffraction measurement. The crystalline perfection of LAPP crystals grown by slow evaporation solution technique (SEST) and SR method were characterized using Vickers microhardness, UV-Vis NIR, chemical etching, dark and photo current measurements. The above study indicates that the crystal quality of the Sankaranarayanan-Ramasamy (SR) method grown LAPP is good compared to the conventional method grown crystal.

  18. Bulk growth of <001> organic nonlinear optical (NLO) L-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) single crystals by SR method

    International Nuclear Information System (INIS)

    A transparent uniaxial L-arginine 4-nitrophenolate 4-nitrophenol dehydrate (LAPP) single crystal having dimension of 20 mm diameter and 45 mm length was grown by Sankaranarayanan-Ramasamy (SR) method with a growth rate of 1 mm per day. Using an identical solution the conventional crystal grown to a dimension of 8×5×5 mm3 was obtained over a period of 30 days. The crystal structure has been confirmed by single crystal X-ray diffraction measurement. The crystalline perfection of LAPP crystals grown by slow evaporation solution technique (SEST) and SR method were characterized using Vickers microhardness, UV-Vis NIR, chemical etching, dark and photo current measurements. The above study indicates that the crystal quality of the Sankaranarayanan-Ramasamy (SR) method grown LAPP is good compared to the conventional method grown crystal

  19. QbD-Based Development and Validation of a Stability-Indicating HPLC Method for Estimating Ketoprofen in Bulk Drug and Proniosomal Vesicular System.

    Science.gov (United States)

    Yadav, Nand K; Raghuvanshi, Ashish; Sharma, Gajanand; Beg, Sarwar; Katare, Om P; Nanda, Sanju

    2016-03-01

    The current studies entail systematic quality by design (QbD)-based development of simple, precise, cost-effective and stability-indicating high-performance liquid chromatography method for estimation of ketoprofen. Analytical target profile was defined and critical analytical attributes (CAAs) were selected. Chromatographic separation was accomplished with an isocratic, reversed-phase chromatography using C-18 column, pH 6.8, phosphate buffer-methanol (50 : 50v/v) as a mobile phase at a flow rate of 1.0 mL/min and UV detection at 258 nm. Systematic optimization of chromatographic method was performed using central composite design by evaluating theoretical plates and peak tailing as the CAAs. The method was validated as per International Conference on Harmonization guidelines with parameters such as high sensitivity, specificity of the method with linearity ranging between 0.05 and 250 µg/mL, detection limit of 0.025 µg/mL and quantification limit of 0.05 µg/mL. Precision was demonstrated using relative standard deviation of 1.21%. Stress degradation studies performed using acid, base, peroxide, thermal and photolytic methods helped in identifying the degradation products in the proniosome delivery systems. The results successfully demonstrated the utility of QbD for optimizing the chromatographic conditions for developing highly sensitive liquid chromatographic method for ketoprofen. PMID:26514627

  20. Changes of copper speciation in maize rhizosphere soil

    International Nuclear Information System (INIS)

    Continuous changes in copper fractionization occurred within the maize rhizosphere. - Chemical forms of copper in the rhizosphere and bulk soil of maize were investigated using rhizobox cultivation and sequential extraction techniques. The copper accumulations were also determined. The results demonstrated that there were continuous changes in copper fractionation within the maize rhizosphere. Initially, the amount of exchangeable copper increased before dropping below the initial level after 40 days or so. Carbonate associated copper followed a similar trend of change, but with a slower pace than the exchangeable copper. The increase in carbonate associated copper only become evident after 30 days, with the net loss occurring after 60 days. There were also initial increases in oxide bound copper as well as decreases in the organic matter associated copper, both followed by a turnover after 40-50 days. The accumulation of copper in the maize plant was found to be biomass dependent. The amount of accumulated copper absorbed in the plant material exceeded the initial quantity of the exchangeable copper in the soil, revealing a transformation from less bioavailable to more bioavailable fractions. During cultivation, decreases in redox potential and increases in pH, dissolved organic carbon (DOC), and microbial activity in the maize rhizosphere were observed. The change in copper speciation may result from root-induced changes in DOC, redox potential, and microbial activity in the rhizosphere

  1. Bulk Moisture and Salinity Sensor

    Science.gov (United States)

    Nurge, Mark; Monje, Oscar; Prenger, Jessica; Catechis, John

    2013-01-01

    Measurement and feedback control of nutrient solutions in plant root zones is critical to the development of healthy plants in both terrestrial and reduced-gravity environments. In addition to the water content, the amount of fertilizer in the nutrient solution is important to plant health. This typically requires a separate set of sensors to accomplish. A combination bulk moisture and salinity sensor has been designed, built, and tested with different nutrient solutions in several substrates. The substrates include glass beads, a clay-like substrate, and a nutrient-enriched substrate with the presence of plant roots. By measuring two key parameters, the sensor is able to monitor both the volumetric water content and salinity of the nutrient solution in bulk media. Many commercially available moisture sensors are point sensors, making localized measurements over a small volume at the point of insertion. Consequently, they are more prone to suffer from interferences with air bubbles, contact area of media, and root growth. This makes it difficult to get an accurate representation of true moisture content and distribution in the bulk media. Additionally, a network of point sensors is required, increasing the cabling, data acquisition, and calibration requirements. measure the dielectric properties of a material in the annular space of the vessel. Because the pore water in the media often has high salinity, a method to measure the media moisture content and salinity simultaneously was devised. Characterization of the frequency response for capacitance and conductance across the electrodes was completed for 2-mm glass bead media, 1- to 2-mm Turface (a clay like media), and 1- to 2-mm fertilized Turface with the presence of root mass. These measurements were then used to find empirical relationships among capacitance (C), the dissipation factor (D), the volumetric water content, and the pore water salinity.

  2. Trace metal speciation in environmental systems

    OpenAIRE

    Rogers, Aisling

    1996-01-01

    The adverse environmental impact of trace metals is an issue of current concern. The increasing recognition that it is the chemical form of a metal which determines its toxicity and bioavailability presents a new challenge for analytical chemists. Techniques are required which are sufficiently sensitive and selective to enable the quantitation o f metal species at lower levels than ever before. The importance of trace metal speciation in environmental samples is reviewed in Chapter 1. The eff...

  3. Phosphorus speciation in Swedish agricultural clay soils

    OpenAIRE

    Eriksson, Ann Kristin

    2016-01-01

    Phosphorus (P) is an important element for crop production, but build-up of excess soil P can promote P leaching and eutrophication of surface waters. To better understand the dynamics of P release from soil to waters, more knowledge is needed about sorption patterns and P speciation in agricultural soils. Two new indices were developed to assess the importance of P sorption to hydroxy-interlayered clay minerals, and to evaluate the amount of hydroxy-interlayering and hydroxy-interlayer ...

  4. Neuroanatomy influences speciation rates among anurans

    OpenAIRE

    Ryan, Michael J.

    1986-01-01

    Evolutionary divergence among animal courtship signals is an important component of the speciation process. In anurans, the preferential response of females to the mating call of conspecific males often maintains reproductive isolation among populations. Much of the information in the call is initially processed in the inner ear, and there is considerable variation in the structure of this organ among lineages of frogs. This variation is responsible for differences in the frequency range to w...

  5. Wormholes in Bulk Viscous Cosmology

    OpenAIRE

    Jamil, Mubasher

    2008-01-01

    We investigate the effects of the accretion of phantom energy with non-zero bulk viscosity onto a Morris-Thorne wormhole. We have found that if the bulk viscosity is large then the mass of wormhole increases rapidly as compared to small or zero bulk viscosity.

  6. The Genetics of Speciation by Reinforcement

    Directory of Open Access Journals (Sweden)

    Ortiz-Barrientos Daniel

    2004-01-01

    Full Text Available Reinforcement occurs when natural selection strengthens behavioral discrimination to prevent costly interspecies matings, such as when matings produce sterile hybrids. This evolutionary process can complete speciation, thereby providing a direct link between Darwin's theory of natural selection and the origin of new species. Here, by examining a case of speciation by reinforcement in Drosophila, we present the first high-resolution genetic study of variation within species for female mating discrimination that is enhanced by natural selection. We show that reinforced mating discrimination is inherited as a dominant trait, exhibits variability within species, and may be influenced by a known set of candidate genes involved in olfaction. Our results show that the genetics of reinforced mating discrimination is different from the genetics of mating discrimination between species, suggesting that overall mating discrimination might be a composite phenomenon, which in Drosophila could involve both auditory and olfactory cues. Examining the genetics of reinforcement provides a unique opportunity for both understanding the origin of new species in the face of gene flow and identifying the genetic basis of adaptive female species preferences, two major gaps in our understanding of speciation.

  7. Sulfur and iron speciation in gas-rich impact-melt glasses from basaltic shergottites determined by microXANES

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, S.R.; Rao, M.N.; Nyquist, L.E. (UofC); (Johnson Space Center)

    2008-04-28

    Sulfur and iron K XANES measurements were made on GRIM glasses from EET 79001. Iron is in the ferrous state. Sulfur speciation is predominately sulfide coordination but is Fe coordinated in Lith B and, most likely, Ca coordinated in Lith A. Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Moessbauer studies on rocks at Meridian and Gusev, whereas MgSO{sub 4} is deduced from MgO-SO{sub 3} correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum and alunogen/S-rich aluminosilicates and halides are detected only in martian meteorites such as shergottites and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. On Earth, volcanic rocks contain measurable quantities of sulfur present as both sulfide and sulfate. Carroll and Rutherford showed that oxidized forms of sulfur may comprise a significant fraction of total dissolved sulfur, if the oxidation state is higher than {approx}2 log fO{sub 2} units relative to the QFM buffer. Terrestrial samples containing sulfates up to {approx}25% in fresh basalts from the Galapagos Rift on one hand and high sulfide contents present in oceanic basalts on the other indicate that the relative abundance of sulfide and sulfate varies depending on the oxygen fugacity of the system. Basaltic shergottites (bulk) such as Shergotty, EET79001 and Zagami usually contain small amounts of sulfur ({approx}0.5%) as pyrrhotite. But, in isolated glass pockets containing secondary salts (known as GRIM glasses) in these meteorites, sulfur is present in high abundance ({approx}1-12%). To

  8. Speciation and Localization of Arsenic in White and Brown Rice Grains

    Energy Technology Data Exchange (ETDEWEB)

    Meharg, Andrew A.; Lombi, Enzo; Williams, Paul N.; Scheckel, Kirk G.; Feldmann, Joerg; Raab, Andrea; Zhu, Yongguan; Islam, Rafiql (EPA); (Bangladesh); (UCopenhagen); (Aberdeen); (Chinese Aca. Sci.)

    2008-06-30

    Synchrotron-based X-ray fluorescence (S-XRF) was utilized to locate arsenic (As) in polished (white) and unpolished (brown) rice grains from the United States, China, and Bangladesh. In white rice As was generally dispersed throughout the grain, the bulk of which constitutes the endosperm. In brown rice As was found to be preferentially localized at the surface, in the region corresponding to the pericarp and aleurone layer. Copper, iron, manganese, and zinc localization followed that of arsenic in brown rice, while the location for cadmium and nickel was distinctly different, showing relatively even distribution throughout the endosperm. The localization of As in the outer grain of brown rice was confirmed by laser ablation ICP?MS. Arsenic speciation of all grains using spatially resolved X-ray absorption near edge structure (?-XANES) and bulk extraction followed by anion exchange HPLC?ICP?MS revealed the presence of mainly inorganic As and dimethylarsinic acid (DMA). However, the two techniques indicated different proportions of inorganic:organic As species. A wider survey of whole grain speciation of white (n = 39) and brown (n = 45) rice samples from numerous sources (field collected, supermarket survey, and pot trials) showed that brown rice had a higher proportion of inorganic arsenic present than white rice. Furthermore, the percentage of DMA present in the grain increased along with total grain arsenic.

  9. Detection and speciation of trace amounts of neptunium and plutonium

    International Nuclear Information System (INIS)

    This paper reports that laser resonance ionization mass spectrometry has been investigated as a method for the detection of trace amounts of neptunium and plutonium. The instrument consists of three tunable pulsed dye lasers pumped by one or two copper vapor lasers and a time-of-flight spectrometer. High selectivity can be achieved by three-step photoionization. Measurements of the isotopic ratios of plutonium yielded a good agreement with mass spectrometric data. By saturating the excitation steps and by using autoionizing states for the ionization step, a detection efficiency of 4 x 10-6 has been determined for plutonium, corresponding to a detection limit of less than 107 atoms. Electrophoretic ion focusing enable s the separation of oxidation states of neptumiun and plutonium. The combination of this analytical technique with radiometric detection method or laser resonance ionization mass spectrometry allows the speciation of neptunium and plutonium at very low concentrations

  10. Influences of Copper Speciation on Toxicity to Microorganisms in Soils

    Institute of Scientific and Technical Information of China (English)

    SHU-JUAN SUN; JIAN XU; SHU-GUI DAI; XUE HAN

    2006-01-01

    Objective To investigate the relationship between copper speciation and microbial features (microbial communities and copper tolerance level) in order to determine the adverse effect of different forms of Cu on microorganisms. Methods Tessier's sequential extraction procedure was used to qualify the different Cu forms (exchangeable, carbonate bound, Fe/Mn oxide bound, residue and organic matter bound), and the copper tolerance level (expressed as IC50, influence concentration) was measured by the plate-count method. Results By simple correlation analysis, the IC50 was positively correlated with the concentration of exchangeable Cu (R2=0.8204), while weakly correlated with other forms of Cu. Conclusion The bacterial community tolerance increases in the copper-contaminated soil while sensitive bacteria decrease in the copper-contaminated soils. The exchangeable Cu exerts high toxicity to microbial communities.

  11. Thermodynamics proposes, kinetics decides, speciation dares: speciation of actinides in biological media

    International Nuclear Information System (INIS)

    After having recalled the content and purpose of his research thesis, the author proposes a detailed overview of the research works he performed thereafter in the field of the speciation of actinides at the level of the organism entry gates and in target tissues. These works therefore concern four important areas of research in radioprotection: bio-kinetic, toxicology, decorporation, and dosimetry studies. The author outlines how speciation studies can be useful for these different areas, and to better understand and describe, and therefore foresee, the biokinetics and toxicity of radionuclides

  12. Explosive bulk charge

    Science.gov (United States)

    Miller, Jacob Lee

    2015-04-21

    An explosive bulk charge, including: a first contact surface configured to be selectively disposed substantially adjacent to a structure or material; a second end surface configured to selectively receive a detonator; and a curvilinear side surface joining the first contact surface and the second end surface. The first contact surface, the second end surface, and the curvilinear side surface form a bi-truncated hemispherical structure. The first contact surface, the second end surface, and the curvilinear side surface are formed from an explosive material. Optionally, the first contact surface and the second end surface each have a substantially circular shape. Optionally, the first contact surface and the second end surface consist of planar structures that are aligned substantially parallel or slightly tilted with respect to one another. The curvilinear side surface has one of a smooth curved geometry, an elliptical geometry, and a parabolic geometry.

  13. The Incredible Bulk

    CERN Document Server

    Fukushima, Keita; Kumar, Jason; Sandick, Pearl; Yamamoto, Takahiro

    2014-01-01

    Recent experimental results from the LHC have placed strong constraints on the masses of colored superpartners. The MSSM parameter space is also constrained by the measurement of the Higgs boson mass, and the requirement that the relic density of lightest neutralinos be consistent with observations. Although large regions of the MSSM parameter space can be excluded by these combined bounds, leptophilic versions of the MSSM can survive these constraints. In this paper we consider a scenario in which the requirements of minimal flavor violation, vanishing $CP$-violation, and mass universality are relaxed, specifically focusing on scenarios with light sleptons. We find a large region of parameter space, analogous to the original bulk region, for which the lightest neutralino is a thermal relic with an abundance consistent with that of dark matter. We find that these leptophilic models are constrained by measurements of the magnetic and electric dipole moments of the electron and muon, and that these models have ...

  14. Bulk muscles, loose cables.

    Science.gov (United States)

    Liyanage, Chamari R D G; Kodali, Venkata

    2014-01-01

    The accessibility and usage of body building supplements is on the rise with stronger internet marketing strategies by the industry. The dangers posed by the ingredients in them are underestimated. A healthy young man came to the emergency room with palpitations and feeling unwell. Initial history and clinical examination were non-contributory to find the cause. ECG showed atrial fibrillation. A detailed history for any over the counter or herbal medicine use confirmed that he was taking supplements to bulk muscle. One of the components in these supplements is yohimbine; the onset of symptoms coincided with the ingestion of this product and the patient is symptom free after stopping it. This report highlights the dangers to the public of consuming over the counter products with unknown ingredients and the consequential detrimental impact on health. PMID:25326558

  15. Stability Indicating RP-HPLC Method Development and Validation of Simultaneous Estimation of Trandolapril and Verapamil Hydrochloride with Forced Degradation Studies in Bulk and Commercial Products

    Directory of Open Access Journals (Sweden)

    Ganipisetty Lakshmi Aswini

    2015-11-01

    Full Text Available A simple reproducible and efficient isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC method has been developed and validated for the simultaneous estimation of Trandolapril and Verapamil. All the drugs were separated on an Inertsil ODS – 3V 150 x 4.6mm, 5µm. The mobile phase, optimized through an experimental design, was a 40:60 (v/v mixture of acetonitrile and triethylamine buffer (pH 3.0 , pumped at a flow rate of 1.3 ml/min. UV detection was performed at 216 nm. The retention time of Verapamil Hydrochloride and Trandolapril was found to be 1.51 min and 3.43 min respectively. The method was validated in the sample concentration ranges of 1.6 - 25µg/ml for Trandolapril and 95-1530µg/ml for Verapamil Hydrochloride, The method demonstrated to be robust, resisting to small deliberate changes in pH and flow rate of the mobile phase. The LOD values were 0.26 µg/ml and 10.3 µg/ml, while the LOQ values were 0.87 µg/ml and 31.1 µg/ml for Trandolapril and Verapamil Hydrochloride respectively. The recoveries for all three levels were above 99%.

  16. Chromium speciation in solid matrices and regulation: a review.

    Science.gov (United States)

    Unceta, N; Séby, F; Malherbe, J; Donard, O F X

    2010-06-01

    In recent years, the extensive use of chromium in industrial processes has led to the promotion of several directives and recommendations by the European Union, that try to limit and regulate the presence of Cr(VI) in the environment and to protect industrial workers using chromium and end-users of manufactured products. As a consequence, new standard methods and analytical procedures have been published at the EU level for Cr(VI) determination in soil, sludge, sediment, and similar waste materials, workplace atmospheres, cement, packaging materials, industrially produced samples, and corrosion-protection layers on some components of vehicles and electrical and electronic equipment. The objective of this article is to summarize the different directives and recommendations and to critically review the currently existing standard methods and the methods published in the literature for chromium speciation in the above mentioned solid matrices, putting the emphasis on the different extraction procedures which have been developed for each matrix. Particular attention has been paid to Cr(III) and Cr(VI) inter-conversions that can occur during extraction and efforts to minimize these unwanted reactions. Although the use of NaOH-Na(2)CO(3) solutions with hot plate extraction seems to be the more widespread procedure, species transformation can still occur and several studies suggest that speciated isotope-dilution mass spectrometry (SIDMS) could be a suitable tool for correction of these interconversions. Besides, recent studies have proved the role of Cr(III) in chromium toxicology. As a consequence, the authors suggest an update of standard methods in the near future. PMID:20099060

  17. SPECIATION IN MAMMALS AND THE GENETIC SPECIES CONCEPT.

    Science.gov (United States)

    Baker, Robert J; Bradley, Robert D

    2006-08-01

    We define a genetic species as a group of genetically compatible interbreeding natural populations that is genetically isolated from other such groups. This focus on genetic isolation rather than reproductive isolation distinguishes the Genetic Species Concept from the Biological Species Concept. Recognition of species that are genetically isolated (but not reproductively isolated) results in an enhanced understanding of biodiversity and the nature of speciation as well as speciation-based issues and evolution of mammals. We review criteria and methods for recognizing species of mammals and explore a theoretical scenario, the Bateson-Dobzhansky-Muller (BDM) model, for understanding and predicting genetic diversity and speciation in mammals. If the BDM model is operating in mammals, then genetically defined phylogroups would be predicted to occur within species defined by morphology, and phylogroups experiencing stabilizing selection will evolve genetic isolation without concomitant morphological diversification. Such species will be undetectable using classical skin and skull morphology (Morphological Species Concept). Using cytochrome-b data from sister species of mammals recognized by classical morphological studies, we estimated the number of phylogroups that exist within mammalian species and hypothesize that there will be >2,000 currently unrecognized species of mammals. Such an underestimation significantly affects conclusions on the nature of speciation in mammals, barriers associated with evolution of genetic isolation, estimates of biodiversity, design of conservation initiatives, zoonoses, and so on. A paradigm shift relative to this and other speciation-based issues will be needed. Data that will be effective in detecting these "morphologically cryptic genetic species" are genetic, especially DNA-sequence data. Application of the Genetic Species Concept uses genetic data from mitochondrial and nuclear genomes to identify species and species boundaries

  18. Laser-induced photoacoustic spectroscopy for the speciation of transuranic elements in natural aquatic systems

    International Nuclear Information System (INIS)

    Laser-induced Photoacoustic Spectroscopy (LPAS) is a new elegant instrumentation for the chemical speciation of acoustic transuranium (TRU) ions in very dilute concentrations (> 10-8 mol L-1). The paper describes the principle of LPAS and its application to the study of the chemical behaviour of TRU ions in natural aquatic systems, the knowledge of which has become increasingly in demand in connection with the safety analysis of nuclear waste disposal in the geosphere. The first part of the paper describes the principle, instrumentation and characteristics of LPAS in aqueous solution, taking particular examples from our own experience. The theoretical estimation of the speciation sensitivity is demonstrated and the result is compared with experiment. The second part deals with the spectral work in aqueous solution and then with the aplication of LPAS for the speciation of TRU ions in groundwater. Some examples demonstrated are hydrolysis reaction, complexation and colloid generation of the Am3+ ion. Speciation sensitivities of U, Np, Pu and Am of different oxidation states in a variety of aqueous solutions are summarized. The application is of course open to a broad field of microchemistry in which the conventional spectrophotometric method has difficulty with sensitivity. (orig.)

  19. Laser-induced photoacoustic spectroscopy for the speciation of transuranic elements in natural aquatic systems

    International Nuclear Information System (INIS)

    Laser-induced photoacoustic spectroscopy (LPAS) is a new elegant instrumentation for the chemical speciation of aquatic transuranium (TRU) ions in very dilute concentrations (>10-8 mol L-1). The paper describes the principle of LPAS and its application to the study of the chemical behaviour of TRU ions in natural aquatic systems, the knowledge of which has become increasingly in demand in connection with the safety analysis of nuclear waste disposal in the geosphere. The first part of the paper describes the principle, instrumentation and characteristics of LPAS in aqueous solution, taking particular examples from our own experience. The theoretical estimation of the speciation sensitivity is demonstrated and the result is compared with experiment. The second part deals with the spectral work in aqueous solution and then with the application of LPAS for the speciation of TRU ions in groundwater. Some examples demonstrated are hydrolysis reaction, complexation and colloid generation of the Am3+ ion. Speciation sensitivities of U, Np, Pu and Am of different oxidation states in a variety of aqueous solutions are summarized. The application is of course open to a broad field of microchemistry in which the conventional spectrophotometric method has difficulty with sensitivity

  20. Study on Effect of Gd (III) Speciation on Ca (II) Speciation in Human Blood Plasma by Computer Simulation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ca (II) speciation and effect of Gd (III) speciation on Ca (II) speciation in human blood plasma were studied by computer simulation. [CaHCO3]+ is a predominant compound species of Ca (II). Gd (III) can compete with Ca (II) for biological molecules. The presence of Gd (III) results in a increase of concentration of free Ca (II) and a decrease of concentration of Ca (II) compounds.

  1. Stability-indicating UHPLC method for determination of nevirapine in its bulk form and tablets: identification of impurities and degradation kinetic study.

    Science.gov (United States)

    Reis, Naialy Fernandes Araújo; de Assis, Jéssica Camille; Fialho, Sílvia Ligório; Pianetti, Gerson Antônio; Fernandes, Christian

    2016-07-15

    Nevirapine (NVP), a non-nucleoside reverse transcriptase inhibitor, is a drug widely used in the treatment of Acquired Immunodeficiency Syndrome (AIDS). The evaluation of NVP stability is of fundamental importance in order to guarantee drug product efficacy, safety and quality. In this study, NVP active pharmaceutical ingredient (API) and tablets were subjected to a detailed study of forced degradation, employing several degrading agents (acid, alkaline, water, metal ions, humidity, heat, light and oxidation agents). In order to determine NVP and the degradation products formed, a stability-indicating UHPLC method using fused core column was developed and validated. The separation was carried out using a Poroshell 120C18 column (100×2.1mm i.d.; 2.7μm particle size) and the mobile phase was composed of acetonitrile and water in a gradient elution, at a flow rate of 0.2ml/min. Chemical structures and mechanisms for the formation of three degradation products were proposed by means of LC/MS-MS. Also, NVP degradation kinetic was studied and its order of degradation evaluated. NVP was degraded in acidic and oxidative conditions and the degradation profile for NVP tablets and API were similar. The stability-indicating method proved to be selective for NVP and its degradation products. Calibration curve was linear in the range of 8-48μg/ml and the method showed to be precise, accurate and robust for both NVP API and tablets, with detection and quantification limits of 0.092μg/ml and 0.174μg/ml, respectively. PMID:27179642

  2. Development and Validation of Stability-Indicating Method for Estimation of Chlorthalidone in Bulk and Tablets with the Use of Experimental Design in Forced Degradation Experiments

    Science.gov (United States)

    Sonawane, Sandeep; Jadhav, Sneha; Rahade, Priya; Chhajed, Santosh; Kshirsagar, Sanjay

    2016-01-01

    Chlorthalidone was subjected to various forced degradation conditions. Substantial degradation of chlorthalidone was obtained in acid, alkali, and oxidative conditions. Further full factorial experimental design was applied for acid and alkali forced degradation conditions, in which strength of acid/alkali, temperature, and time of heating were considered as independent variables (factors) and % degradation was considered as dependent variable (response). Factors responsible for acid and alkali degradation were statistically evaluated using Yates analysis and Pareto chart. Furthermore, using surface response curve, optimized 10% degradation was obtained. All chromatographic separation was carried out on Phenomenex HyperClone C 18 column (250 × 4.6 mm, 5 μ), using mobile phase comprising methanol : acetonitrile : phosphate buffer (20 mM) (pH 3.0 adjusted with o-phosphoric acid): 30 : 10 : 60% v/v. The flow rate was kept constant at 1 mL/min and eluent was detected at 241 nm. In calibration curve experiments, linearity was found to be in the range of 2–12 μg/mL. Validation experiments proved good accuracy and precision of the method. Also there was no interference of excipients and degradation products at the retention time of chlorthalidone, indicating specificity of the method. PMID:27123364

  3. LOGISTICAL CRITERIONS AND STRATEGIES FOR STORAGE OF BULK MATERIALS

    OpenAIRE

    Péter Telek

    2009-01-01

    The aim of my paper is to analyze the applicability of criterions used for selection of storage methods of individual units and general logistic strategies for storage of bulk materials. To reach this aim paper gives an overview about the advanced storage methods of bulk materials and their application possibilities. The second part shows the main criterions and logistic strategies in deep and describes their usability for bulk materials.

  4. 体积置换法直接测量土壤质量含水率及土壤容重%Volume replacement method for direct measurement of soil moisture and bulk density

    Institute of Scientific and Technical Information of China (English)

    马玉莹; 雷廷武; 张心平; 陈逸欣

    2013-01-01

    Direct measurement of soil moisture and bulk density is the foundation of related research and applications, which is of great importance in such studies and applications as soil mechanics, crop production, irrigation and ecological environments. This paper presents a new method for direct measurement of soil moisture and soil bulk density based on volume replacement, which is equivalent to the conventional oven-dry method. The measurement principle is based on the model of soil three-phase composition, soil particles, water and air. Its volume and mass are partitioned into three fractions of these substances. The initial soil mass is approximately determined by the soil particles and water when the air mass is neglected. The measurement principles are as the follows. The samples used for measurements of moisture content and bulk density were taken by corers of known volumes and were weighted to determine their initial masses before they were filled with water to saturation state to replace all the air-filled spaces in the soil samples. The initial/original weight of the soil sample and that after saturation were used to compute the water mass required to replace the air-filled volume. Under the known soil particle density, the given volume as defined by the corer and the determined air-filled space volume, the original soil water content and soil bulk density can be calculated. An experimental system and the related algorithm procedures were proposed for the direct measurement of water content and soil bulk density. The standard soil corers were used to prepare the soil samples under designed bulk densities. The saturators were used to pre-saturate the soil samples. The samples were dripped with water to ensure their saturation during the measurement. Three soil materials, a clay loam from Yangling of Shaanxi province, a silt loam from Beijing and a red clay from Jiangxi province, were used for the demonstrational experiments to illustrate the measurement

  5. Comparison of preparation methods for ceria catalyst and the effect of surface and bulk sulfates on its activity toward NH3-SCR

    International Nuclear Information System (INIS)

    Highlights: • The CeO2-SH catalyst showed >97% conversion of NOx at 230–450 °C. • The resistance to Na and K of the CeO2 catalyst was enhanced significantly. • Surface sulfate species bind to Ce4+ improve the N2 selectivity in NH3-SCO. -- Abstract: A series of CeO2 catalysts prepared with sulfate (S) and nitrate (N) precursors by hydrothermal (H) and precipitation (P) methods were investigated in selective catalytic reduction of NOx by NH3 (NH3-SCR). The catalytic activity of CeO2 was significantly affected by the preparation methods and the precursor type. CeO2-SH, which was prepared by hydrothermal method with cerium (IV) sulfate as a precursor, showed excellent SCR activity and high N2 selectivity in the temperature range of 230–450 °C. Based on the results obtained by temperature-programmed reduction (H2-TPR), transmission infrared spectra (IR) and thermal gravimetric analysis (TGA), the excellent performance of CeO2-SH was correlated with the surface sulfate species formed in the hydrothermal reaction. These results indicated that sulfate species bind with Ce4+ on the CeO2-SH catalyst, and the specific sulfate species, such as Ce(SO4)2 or CeOSO4, were formed. The adsorption of NH3 was promoted by these sulfate species, and the probability of immediate oxidation of NH3 to N2O on Ce4+ was reduced. Accordingly, the selective oxidation of NH3 was enhanced, which contributed to the high N2 selectivity in the SCR reaction. However, the location of sulfate on the CeO2-SP catalyst was different. Plenty of sulfate species were likely deposited on CeO2-SP surface, covering the active sites for NO oxidation, which resulted in poor SCR activity in the test temperature range. Moreover, the resistance to alkali metals, such as Na and K, was improved over the CeO2-SH catalyst

  6. MoS2 nanoparticles and h-BN nanosheets from direct exfoliation of bulk powder: one-step synthesis method

    International Nuclear Information System (INIS)

    We report facile synthesis of MoS2 nanoparticles and h-BN nanosheets using ultrasonication method in suitable solvents such as N-Methyl-2-pyrrolidone and ethylene glycol, respectively. The average size of MoS2 nanoparticles observed from TEM analysis were 4–5 nm and about a few hundreds of nm for h-BN nanosheets. Raman spectroscopy carried out on nanoparticle samples confirms the formation of MoS2 nanoparticles and h-BN nanosheets. UV–vis absorption and photoluminescence (PL) measurements carried out on the products show typical absorption and luminescence spectra of MoS2 and h-BN. Further, we attempted to decorate gold nanoparticles on nanosheets of MoS2 and h-BN which show subsequent change in Raman spectra due to charge transfer interaction. (paper)

  7. Development of superconductor bulk for superconductor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong (and others)

    2008-08-15

    Current carrying capacity is one of the most important issues in the consideration of superconductor bulk materials for engineering applications. There are numerous applications of Y-Ba-Cu-O (YBCO) bulk superconductors e.g. magnetic levitation train, flywheel energy storage system, levitation transportation, lunar telescope, centrifugal device, magnetic shielding materials, bulk magnets etc. Accordingly, to obtain YBCO materials in the form of large, single crystals without weak-link problem is necessary. A top seeded melt growth (TSMG) process was used to fabricate single crystal YBCO bulk superconductors. The seeded and infiltration growth (IG) technique was also very promising method for the synthesis of large, single-grain YBCO bulk superconductors with good superconducting properties. 5 wt.% Ag doped Y211 green compacts were sintered at 900 .deg. C {approx} 1200 .deg.C and then a single crystal YBCO was fabricated by an infiltration method. A refinement and uniform distribution of the Y211 particles in the Y123 matrix were achieved by sintering the Ag-doped samples. This enhancement of the critical current density was ascribable to a fine dispersion of the Y211 particles, a low porosity and the presence of Ag particles. In addition, we have designed and manufactured large YBCO single domain with levitation force of 10-13 kg/cm{sup 2} using TSMG processing technique.

  8. Arsenic speciation in solids using X-ray absorption spectroscopy

    Science.gov (United States)

    Foster, Andrea L.; Kim, Chris S.

    2014-01-01

    Synchrotron-based X-ray absorption spectroscopy (XAS) is an in situ, minimally-destructive, element-specific, molecular-scale structural probe that has been employed to study the chemical forms (species) of arsenic (As) in solid and aqueous phases (including rocks, soils, sediment, synthetic compounds, and numerous types of biota including humans) for more than 20 years. Although several excellent reviews of As geochemistry and As speciation in the environment have been published previously (including recent contributions in this volume), the explosion of As-XAS studies over the past decade (especially studies employing microfocused X-ray beams) warrants this new review of the literature and of data analysis methods.

  9. The potential of arsenic speciation in molluscs for environmental monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Soeroes, Csilla; Bodo, Erzsebet Tuende; Fodor, Peter [Department of Applied Chemistry, Faculty of Food Science, Szent Istvan University, Villanyi ut 29-33, 1118, Budapest (Hungary); Morabito, Roberto [ENEA C.R. CASACCIA-TEIN/CHIM, Via Anguillarese, 301-00060, Rome (Italy)

    2003-09-01

    This paper reports the assessment of total arsenic and six arsenic species (As(III), As(V), MMA, DMA, AsBet, AsCol) as contaminants of mussel samples collected around the island of Sardinia and in the Gulf of Venice. The samples were analysed using cation- and anion-exchange HPLC-HG-AFS for speciation and ICP-AES for the total As determination. To ensure the robustness of the routine analytical method, the technique was validated using a candidate reference material, BCR-710, and good agreement was obtained. It was recognised that higher total arsenic concentration in mussels does not necessarily result in higher toxicity of mussel samples. (orig.)

  10. Concentration and speciation of heavy metals during water hyacinth composting.

    Science.gov (United States)

    Singh, Jiwan; Kalamdhad, Ajay S

    2012-11-01

    The Tessier sequential extraction method was employed to investigate the changes in heavy metals speciation (Zn, Cu, Mn, Fe, Pb, Ni, Cd and Cr) during water hyacinth (Eichhornia crassipes) composting. Results showed that, the contents of total metals concentration were increased during the composting process. The largest proportion of metals was found in the residual fraction which was in more stable form and is consequently considered unavailable for plant uptake. Reducible and oxidizable fractions of Ni, Pb and Cd were not found in all trials during water hyacinth composting. The concentrations of Cu and Cd were very low comparative to the other metals, but the percentage of exchangeable and carbonate fractions were similar as other metals. From this study it can be concluded that the appropriate proportion of cattle manure addition (Trial 4) significantly reduced the mobile and easily available fractions (exchangeable and carbonate fractions) during the composting process. PMID:22989643

  11. Speciation and migration of 129I in soil profiles

    DEFF Research Database (Denmark)

    Luo, Maoyi; Hou, Xiaolin; Zhou, Weijian;

    2013-01-01

    A method has been developed for speciation analysis of ultra low level 129I in soil using sequential extraction combined with coprecipitation for separation of carrier free iodine and AMS measurement of 129I. Two loess profiles collected from northwest China were analyzed for species of 129I and...... suggest that migration of iodine downwards in the soil profile is a slow process; the oxides and residue are the less mobile fractions of iodine. © 2012 Elsevier Ltd....... 127I. Similar partitioning of 129I and 127I was observed in the loess profiles, the distribution of iodine isotopes followed an order of organic > leachable > reducible > residue. The 129I concentrations and 129I/127I ratios decreased exponentially with the depth, and 2 orders of magnitude lower in...

  12. Inflation from bulk viscosity

    CERN Document Server

    Bamba, Kazuharu

    2015-01-01

    We explore the perfect fluid description of the inflationary universe. In particular, we investigate a fluid model with the bulk-viscosity term. We find that the three observables of inflationary cosmology: the spectral index of the curvature perturbations, the tensor-to-scalar ratio of the density perturbations, and the running of the spectral index, can be consistent with the recent Planck results. We also reconstruct the explicit equation of state (EoS) of the viscous fluid from the spectral index of the curvature perturbations compatible with the Planck analysis. In the reconstructed models of the viscous fluid, the tensor-to-scalar ratio of the density perturbations can satisfy the constraints obtained from the Planck satellite. The running of the spectral index can explain the Planck data. In addition, it is demonstrated that in the reconstructed models of the viscous fluid, the graceful exit from inflation can be realized. Furthermore, we show that the singular inflation can occur in the viscous fluid ...

  13. Speciation of volatile organic compounds from poultry production

    Science.gov (United States)

    Trabue, Steven; Scoggin, Kenwood; Li, Hong; Burns, Robert; Xin, Hongwei; Hatfield, Jerry

    2010-09-01

    Volatile organic compounds (VOCs) emitted from poultry production are leading source of air quality problems. However, little is known about the speciation and levels of VOCs from poultry production. The objective of this study was the speciation of VOCs from a poultry facility using evacuated canisters and sorbent tubes. Samples were taken during active poultry production cycle and between production cycles. Levels of VOCs were highest in areas with birds and the compounds in those areas had a higher percentage of polar compounds (89%) compared to aliphatic hydrocarbons (2.2%). In areas without birds, levels of VOCs were 1/3 those with birds present and compounds had a higher total percentage of aliphatic hydrocarbons (25%). Of the VOCs quantified in this study, no single sampling method was capable of quantifying more than 55% of compounds and in several sections of the building each sampling method quantified less than 50% of the quantifiable VOCs. Key classes of chemicals quantified using evacuated canisters included both alcohols and ketones, while sorbent tube samples included volatile fatty acids and ketones. The top five compounds made up close to 70% of VOCs and included: 1) acetic acid (830.1 μg m -3); 2) 2,3-butanedione (680.6 μg m -3); 3) methanol (195.8 μg m -3); 4) acetone (104.6 μg m -3); and 5) ethanol (101.9 μg m -3). Location variations for top five compounds averaged 49.5% in each section of the building and averaged 87% for the entire building.

  14. Sample treatment in chromatography-based speciation of organometallic pollutants.

    Science.gov (United States)

    Gómez-Riza, J L; Morales, E; Giráldez, I; Sánchez-Rodas, D; Velasco, A

    2001-12-14

    Speciation analysis is nowadays performed routinely in many laboratories to control the quality of the environment, food and health. Chemical speciation analyses generally include the study of different oxidation state of elements or individual organometallic compounds. The determination of the different chemical forms of elements is still an analytical challenge, since they are often unstable and concentrations in different matrices of interest are in the microg l(-1) or even in the ng l(-1) range (e.g., estuarine waters) or ng g(-1) in sediments and biological tissues. For this reason, sensitive and selective analytical atomic techniques are being used as available detectors for speciation, generally coupled with chromatography for the time-resolved introduction of analytes into the atomic spectrometer. The complexity of these instrumental couplings has a straightforward consequence on the duration of the analysis, but sample preparation to separate and transfer the chemical species present in the sample into a solution to be accepted readily by a chromatographic column is the more critical step of total analysis, and demands considerable operator skills and time cost. Traditionally, liquid-liquid extraction has been employed for sample treatment with serious disadvantages, such as consumption, disposal and long-term exposure to organic solvent. In addition, they are usually cumbersome and time-consuming. Therefore, the introduction of new reagents such as sodium tetraethylborate for the simultaneous derivatization of several elements has been proposed. Other possibilities are based in the implementation of techniques for efficient and accelerated isolation of species from the sample matrix. This is the case for microwave-assisted extraction, solid-phase extraction and microextraction, supercritical fluid extraction or pressurized liquid extraction, which offer new possibilities in species treatment, and the advantages of a drastic reduction of the extraction

  15. Quantitative HPLC-ICP-MS analysis of antimony redox speciation in complex sample matrices: new insights into the Sb-chemistry causing poor chromatographic recoveries

    OpenAIRE

    Hansen, Claus; Schmidt, Bjørn; Larsen, Erik Huusfeldt; Gammelgaard, Bente; Stürup, Stefan; Hansen, Helle Rüsz

    2011-01-01

    In solution antimony exists either in the pentavalent or trivalent oxidation state. As Sb(III) is more toxic than Sb(V), it is important to be able to perform a quantitative speciation analysis of Sb’s oxidation state. The most commonly applied chromatographic methods used for this redox speciation analysis do, however, often show a low chromatographic Sb recovery when samples of environmental or biological origin are analysed. In this study we explored basal chemistry of antimony and found t...

  16. Speciation of arsenic and mercury in feed: why and how?

    DEFF Research Database (Denmark)

    Hedegaard, Rikke Susanne Vingborg; Sloth, Jens Jørgen

    The understanding of the mechanisms of biological activities and biotransformation of trace elements such as arsenic and mercury has improved during recent years with the help of chemical speciation studies. However, the most important practical application of elemental speciation is in the area of...... toxicology. Toxicological knowledge on the individual trace element species can lead to more specific legislation of hazardous substances found in feed. Examples here are arsenic, where the inorganic forms are the most toxic, and mercury, where the organic form methylmercury is more toxic than inorganic...... mercury. In the present paper an overview of the current knowledge on arsenic and mercury speciation in feed and analytical methodologies for arsenic and mercury speciation analysis are given. Additionally the current status and expected future developments within legislation for trace element speciation...

  17. Speciation of arsenic and mercury in feed: why and how?

    DEFF Research Database (Denmark)

    Hedegaard, Rikke Susanne Vingborg; Sloth, Jens Jørgen

    2011-01-01

    The understanding of the mechanisms of biological activities and biotransformation of trace elements such as arsenic and mercury has improved during recent years with the help of chemical speciation studies. However, the most important practical application of elemental speciation is in the area of...... toxicology. Toxicological knowledge on the individual trace element species can lead to more specific legislation of hazardous substances found in feed. Examples here are arsenic, where the inorganic forms are the most toxic, and mercury, where the organic form methylmercury is more toxic than inorganic...... mercury. In the present paper an overview of the current knowledge on arsenic and mercury speciation in feed and analytical methodologies for arsenic and mercury speciation analysis are given. Additionally the current status and expected future developments within legislation for trace element speciation...

  18. Thermodynamics and speciation: Solubility of PuO2 and Pu(OH)4 and electrophoretic speciation of Np ions

    International Nuclear Information System (INIS)

    This report contains experimental results of two separate subjects: Solubility products of crystalline PuO2 and amorphous Pu(OH)4 separation of Np oxidation states with continuous electrophoretic ion focusing, which are presented separately in part A and B, respectively. The new solubility products of Pu oxide and hydroxide are determined to be log Ksp=-60.20±0.17 and -57.85±0.05, respectively. The free energy of formation for Pu(OH)4(am) is -1141 kJ mol-1. The chemical speciation method using continuous electrophoretic ion focusing has been examined to separate Np(IV) and Np(V) in the picomol contraction under different experimental conditions, i.e. varying pH, complexing agent and medium conductivity. A successful separation of Np ions of two important oxidation states is demonstrated. (orig.)

  19. Analytical aspects of technetium speciation in spinach plants

    Energy Technology Data Exchange (ETDEWEB)

    Harms, A.V

    1998-12-31

    Spinach (Spinacea oleracea L.) is used as a model plant for terrestrial systems, because of its relation to the human food chain, its ability to accumulate heavy metals, and certain experimental advantages, e.g., the relative ease of cultivation of the seedlings and the relative ease of maceration of its leaves. The role of technetium in this research with its chemical, environmental and analytical aspects is discussed in Chapter 2. Chapters 3, 4, and 5, are dedicated to a closer look at the design of a reliable speciation method using size-exclusion chromatography (SEC). Chapter 3 illustrates the role which a `protective` compound, i.e., 2-mercaptoethanol (2-ME), an inhibitor of polyphenol oxidase, might play in plant-Tc speciation studies. The reactivity of TcO{sub 4}{sup {sup -}} and two Tc model species, i.e., anionic Tc-DTPA and cationic Tc-cyclam, with 2-ME is discussed. The Tc species are separated with low- pressure SEC, using Sephadex as stationary phase. It is shown that Tc-DTPA does react with 2-ME, presumably resulting in the formation of a Tc-complex. In Chapter 4 the development of a `mild` high-performance SEC method for separation of Tc compounds is described. It is shown that non-size effects enhance the separation characteristics of this technique resulting in the separation of TcO{sub 4}{sup {sup -}}, Tc-DTPA, and Tc-cyclam. Moreover, it is shown that the extent of these non-size effects has a close relation with the nature of the Tc species, temperature, ionic strength of the mobile phase, and nature of the stationary phase. One of the stationary phases, i.e., a copolymer of 2-hydroxyethyl methacrylate and ethylene dimethacrylate (HEMA), is also used in Chapter 5 to separate TcO{sub 4}{sup {sup -}} from plant-induced Tc species (TcX). Chapter 5 is dedicated to the development of an analytical procedure for Tc speciation in spinach plants using a dual Tc radiotracer technique. Chapters 6 and 7 are dedicated to a further investigation of the

  20. Analytical aspects of technetium speciation in spinach plants

    International Nuclear Information System (INIS)

    Spinach (Spinacea oleracea L.) is used as a model plant for terrestrial systems, because of its relation to the human food chain, its ability to accumulate heavy metals, and certain experimental advantages, e.g., the relative ease of cultivation of the seedlings and the relative ease of maceration of its leaves. The role of technetium in this research with its chemical, environmental and analytical aspects is discussed in Chapter 2. Chapters 3, 4, and 5, are dedicated to a closer look at the design of a reliable speciation method using size-exclusion chromatography (SEC). Chapter 3 illustrates the role which a 'protective' compound, i.e., 2-mercaptoethanol (2-ME), an inhibitor of polyphenol oxidase, might play in plant-Tc speciation studies. The reactivity of TcO4- and two Tc model species, i.e., anionic Tc-DTPA and cationic Tc-cyclam, with 2-ME is discussed. The Tc species are separated with low- pressure SEC, using Sephadex as stationary phase. It is shown that Tc-DTPA does react with 2-ME, presumably resulting in the formation of a Tc-complex. In Chapter 4 the development of a 'mild' high-performance SEC method for separation of Tc compounds is described. It is shown that non-size effects enhance the separation characteristics of this technique resulting in the separation of TcO4-, Tc-DTPA, and Tc-cyclam. Moreover, it is shown that the extent of these non-size effects has a close relation with the nature of the Tc species, temperature, ionic strength of the mobile phase, and nature of the stationary phase. One of the stationary phases, i.e., a copolymer of 2-hydroxyethyl methacrylate and ethylene dimethacrylate (HEMA), is also used in Chapter 5 to separate TcO4- from plant-induced Tc species (TcX). Chapter 5 is dedicated to the development of an analytical procedure for Tc speciation in spinach plants using a dual Tc radiotracer technique. Chapters 6 and 7 are dedicated to a further investigation of the speciation of TcX itself with extraction and

  1. Chemical speciation code CHEMSPEC and its applications

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The adsorption and migration behavior of a radionuclide in geological media heavily depends on its chemical forms in a given chemical environment.In order to predict the temporal and spatial distribution of radionuclides around a disposal site when its canister is damaged,it is necessary to develop coupled chemical speciation-solute transport models and relevant software.For that reason,we wrote a new chemical speciation program CHEMSPEC.In this paper,the principles and structure of CHEMSPEC are briefly described,and the strategy and algorithms that were used in this code are interpreted in some detail,such as the measures adopted to prevent divergence in iteratively solving the mass balance equations,the "predictor-corrector" algorithm for calculation of the number and quantities of solid species formed,and the alternate use of "freezing" and "defreezing" oxidation states in handling of co-existent redox and precipitation equilibria.Four examples are given to illustrate CHEMSPEC’s features and capabilities.

  2. Arsenic and chromium speciation in an urban contaminated soil.

    Science.gov (United States)

    Landrot, Gautier; Tappero, Ryan; Webb, Samuel M; Sparks, Donald L

    2012-08-01

    The distribution and speciation of As and Cr in a contaminated soil were studied by synchrotron-based X-ray microfluorescence (μ-XRF), microfocused X-ray absorption spectroscopy (μ-XAS), and bulk extended X-ray absorption fine structure spectroscopy (EXAFS). The soil was taken from a park in Wilmington, DE, which had been an important center for the leather tanning industry along the Atlantic seaboard of the United States, until the early 20th century. Soil concentrations of As, Cr, and Pb measured at certain locations in the park greatly exceeded the background levels of these heavy metals in the State of Delaware. Results show that Cr(III) and As(V) species are mainly present in the soil, with insignificant amounts of Cr(VI) and As(III). Micro-XRF maps show that Cr and Fe are distributed together in regions where their concentrations are diffuse, and at local spots where their concentrations are high. Iron oxides, which can reduce Cr(VI) to Cr(III), are present at some of these hot spots where Cr and Fe are highly concentrated. Arsenic is mainly associated with Al in the soil, and to a minor extent with Fe. Arsenate may be sorbed to aluminum oxides, which might have transformed after a long period of time into an As-Al precipitate phase, having a structure and chemical composition similar to mansfieldite (AlAsO(4)⋅2H(2)O). The latter hypothesis is supported by the fact that only a small amount of As present in the soil was desorbed using the characteristic toxicity leaching procedure tests. This suggests that As is immobilized in the soil. PMID:22520924

  3. Trace metals speciation by HPLC with plasma source mass spectrometry detection.

    OpenAIRE

    Byrdy, F A; Caruso, J A

    1995-01-01

    The analysis of environmental and biological samples often requires detection at the parts per billion (ppb) level. Plasma source mass spectrometry has potential as a method for the analysis and speciation of trace elements. This is due to the technique's highly selective nature and excellent sensitivity. In comparison to atomic emission detection, detection limits are usually two to three orders of magnitude lower for plasma MS determinations. Interfacing HPLC with plasma MS provides a means...

  4. The speciation of copper (II)/ethylenediamine/oxalate system by evolving factor analysis

    OpenAIRE

    Ren, Shouxin; Gao, Ling

    1995-01-01

    Principal component analysis and evolving factor analysis were applied to the study of the speciation of Cu (II)/ethylenediamine/ oxalate. Two programs were designed, based on mathematical algorithms. Error functions were calculated for evaluating the number of species. Submatrix analysis plots were constructed to estimate the species present in the system. The method should prove useful in studies of complex systems in environmental samples.

  5. Speciation analysis of trace elements, radionuclides, macromolecules and nanoparticles using neutron activation and synchrotron radiation

    International Nuclear Information System (INIS)

    Speciation analysis is defined by IUPAC as the analytical activities of identifying and/or measuring the quantities of one or more individual chemical species in a sample. It includes isotopic composition of an element, electronic and oxidation states of an element, distribution of an element among different inorganic complexes, and compounds, organometallic compounds, macromolecular compounds and complexes. In this lecture we will describe the methods developed in our laboratory to separate

  6. Mercury speciation in polluted soils by combined spectroscopic and microspectroscopic techniques employing synchrotron generated x-rays

    International Nuclear Information System (INIS)

    Full text: Soil samples collected inside and outside an industrial polluted area of national environmental interest located in 'Val Basento' (Basilicata, Italy) have been studied by a combination of different advanced analytical techniques exploiting high intensity synchrotron generated x-rays. Mercury (Hg) concentration in the soil ranged from 1 up to 250 μg/g. Bulk EXAFS (Extended x-ray Absorption Fine Structure spectroscopy) and XANES (x-ray Absorption Near Edge Structure spectroscopy) were performed on soil samples sieved at 2 mm and on the clay fraction (2. Simultaneous to μ-XRF spectra, microdiffraction patterns were collected in each point of the maps, in order to identify any correlation between Hg and its mineralogical forms. Once points of interest were localized, μ-XANES spectra were collected and compared with the spectra of known Hg standard compounds. The combination of bulk XAS and microbeam measurements not only provide a detailed Hg speciation at the microscale level, enables better interpretation of the higher length bulk scale XAS spectra in the light of the more easily manageable information obtained from microanalyses. From this combined synchrotron x-ray spectroscopic investigation, we find that Hg was mainly speciated as HgS (cinnabar) and Hg(0) in the samples collected inside the industrial site and as Hg2Cl2, HgCl2 and Hg bound to organic matter in the samples collected in the areas surrounding the industrial site. Quantification of the percentage of the various Hg forms in the soil samples was also obtained. This type of pollution is typical of industrial areas where chlor-alkali plants have been operating in the past. The detailed Hg speciation will allow for a better assessment of the environmental and human risk connected to Hg contamination of these soils, as well as to develop more effective remediation strategies for an environmental restoration of the area. (author)

  7. Performance and applications of quench melt-growth bulk magnets

    Science.gov (United States)

    Nariki, S.; Teshima, H.; Morita, M.

    2016-03-01

    This paper describes the progress in quench melt-growth (QMG) bulk magnets, developed by the Nippon Steel & Sumitomo Metal Corporation, which consist of single crystalline RE123 phase and finely dispersed RE211 particles. QMG bulks can trap high magnetic fields. The field-trapping ability of QMG bulks is largely increased with an improvement in its J c and size, promising the realization of various applications such as flywheel energy-storage systems, ship motors, NMR/MRI spectrometers, wind-power generators and so on. Intensive research has revealed that the optimal RE element is different depending on application requirements. Gd-QMG bulk is the most promising material for several high-field engineering applications. The trapped magnetic field of Gd-QMG bulk 60 mm in diameter at 77 K is twice as large as that of Y-QMG bulk with a similar size due to its excellent J c properties. The large Gd-based QMG bulks up to 150 mm in diameter are fabricated by incorporating the RE compositional gradient method. Compact NMR/MRI spectrometers are one of the promising applications of bulk superconductors. Eu-QMG bulks are suitable for NMR magnets. NMR applications require extremely homogeneous magnetic fields. In the Eu-system, the small paramagnetic moment of a Eu ion compared to a Gd ion improves the field homogeneity in the bulk. For the application of current leads, Dy-based QMG is available by utilizing a low thermal conductivity.

  8. Testing gradual and speciational models of evolution in extant taxa: the example of ratites.

    Science.gov (United States)

    Laurin, M; Gussekloo, S W S; Marjanović, D; Legendre, L; Cubo, J

    2012-02-01

    Ever since Eldredge and Gould proposed their model of punctuated equilibria, evolutionary biologists have debated how often this model is the best description of nature and how important it is compared to the more gradual models of evolution expected from natural selection and the neo-Darwinian paradigm. Recently, Cubo proposed a method to test whether morphological data in extant ratites are more compatible with a gradual or with a speciational model (close to the punctuated equilibrium model). As shown by our simulations, a new method to test the mode of evolution of characters (involving regression of standardized contrasts on their expected standard deviation) is easier to implement and more powerful than the previously proposed method, but the Mesquite module comet (aimed at investigating evolutionary models using comparative data) performs better still. Uncertainties in branch length estimates are probably the largest source of potential error. Cubo hypothesized that heterochronic mechanisms may underlie morphological changes in bone shape during the evolution of ratites. He predicted that the outcome of these changes may be consistent with a speciational model of character evolution because heterochronic changes can be instantaneous in terms of geological time. Analysis of a more extensive data set confirms his prediction despite branch length uncertainties: evolution in ratites has been mostly speciational for shape-related characters. However, it has been mostly gradual for size-related ones. PMID:22107024

  9. Speciation of chromium, copper, iron, manganese, nickel, and zinc of sediment from the Densu River by sequential extraction

    International Nuclear Information System (INIS)

    Total concentrations of the broad metal spectrum and speciation of Cr, Cu, Fe, Ni, Mn and Zn in sediments of River Densu are studied in order to establish the extent of pollution and their capacity of remobilization. Eight composite samples were analyzed, major components of the sediments were studied using Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrophotometer (AAS). From the results obtained, it can be concluded that the sediment has Cd value above the normal range. The distribution of the elements in various fractions depends largely on the element. Most of the elements have the bulk of their concentration in the residual fraction. (author)

  10. Crevice chemistry estimation from bulk water chemistry

    International Nuclear Information System (INIS)

    Since the first PWR plant in Japan started commercial operation in 1970, 22 plants are running in Japan as of the end of 1994. The main purpose of secondary water chemistry control is to minimize the corrosion possibility of the secondary system equipment, especially steam generators (SG). To achieve this objective, much effort has been concentrated on improving secondary water chemistry control. As a result of this effort, the recent secondary water chemistry in Japanese plants is well maintained in every stage of operation. However, to ensure and improve the reliability of SG, it is necessary to control crevice environments, which are located at tube/tube support plate intersections and under the sludge pile on the tube sheet. According to recent crevice monitoring examination results, the concentration behavior impurities in SG bulk water at the crevice is different for each species, and SG bulk water and crevice chemical compositions are not always equal. From these results, to control the crevice chemistry, improving bulk water chemistry control methods and a new type of molar ratio control index is needed. This paper introduces a brief summary of a recent crevice chemistry evaluation technique and bulk water chemistry control method, which is employed for crevice chemistry control, based on crevice monitoring examination results

  11. Genomic islands of speciation in Anopheles gambiae.

    Directory of Open Access Journals (Sweden)

    2005-09-01

    Full Text Available The African malaria mosquito, Anopheles gambiae sensu stricto (A. gambiae, provides a unique opportunity to study the evolution of reproductive isolation because it is divided into two sympatric, partially isolated subtaxa known as M form and S form. With the annotated genome of this species now available, high-throughput techniques can be applied to locate and characterize the genomic regions contributing to reproductive isolation. In order to quantify patterns of differentiation within A. gambiae, we hybridized population samples of genomic DNA from each form to Affymetrix GeneChip microarrays. We found that three regions, together encompassing less than 2.8 Mb, are the only locations where the M and S forms are significantly differentiated. Two of these regions are adjacent to centromeres, on Chromosomes 2L and X, and contain 50 and 12 predicted genes, respectively. Sequenced loci in these regions contain fixed differences between forms and no shared polymorphisms, while no fixed differences were found at nearby control loci. The third region, on Chromosome 2R, contains only five predicted genes; fixed differences in this region were also verified by direct sequencing. These "speciation islands" remain differentiated despite considerable gene flow, and are therefore expected to contain the genes responsible for reproductive isolation. Much effort has recently been applied to locating the genes and genetic changes responsible for reproductive isolation between species. Though much can be inferred about speciation by studying taxa that have diverged for millions of years, studying differentiation between taxa that are in the early stages of isolation will lead to a clearer view of the number and size of regions involved in the genetics of speciation. Despite appreciable levels of gene flow between the M and S forms of A. gambiae, we were able to isolate three small regions of differentiation where genes responsible for ecological and behavioral

  12. SPECIATION OF SELENIUM(IV) AND SELENIUM(VI) USING COUPLED ION CHROMATOGRAPHY: HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY

    Science.gov (United States)

    A simple method was developed to speciate inorganic selenium in the microgram per liter range using coupled ion chromatography-hydride generation atomic absorption spectrometry. Because of the differences in toxicity and adsorption behavior, determination of the redox states selenite, Se(IV), and s...

  13. Selective arsenic speciation analysis of human urine reference materials using gradient elution ion-exchange HPLC-ICP-MS

    DEFF Research Database (Denmark)

    Sloth, Jens Jørgen; Larsen, Erik Huusfeldt; Julshamn, K.

    2004-01-01

    identical with the reference values given for total arsenic. The obtained values for arsenobetaine and dimethylarsinic acid were identical with the values certified for the NIES No. 18 urine CRM. The speciation data presented here may be valuable for the quality assurance of analytical method development...

  14. Selenium speciation analysis of Misgurnus anguillicaudatus selenoprotein by HPLC-ICP-MS and HPLC-ESI-MS/MS

    Science.gov (United States)

    Analytical methods for selenium (Se) speciation were developed using high performance liquid chromatography (HPLC) coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionization tandem mass spectrometry (ESI-MS/MS). Separations of selenomethionine (Se-Met) and sel...

  15. Mining the bulk positron lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Aourag, H.; Guittom, A. [Centre de Recherche Nucleaire d' Alger (CRNA), Alger Gare - Algiers (Algeria)

    2009-02-15

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Mining the bulk positron lifetime

    International Nuclear Information System (INIS)

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Advances in bulk port development

    Energy Technology Data Exchange (ETDEWEB)

    Soros, P. (Soros Associates Consulting Engineers, New York, NY (USA))

    1991-03-01

    The article features several recently developed bulk ports which illustrate aspects of new technology or concepts in maritime transport. Low handling capacity bulk terminals at Ponta da Madeira, Brazil and Kooragang Island, Australia and the low-cost bulk port at Port of Corpus Christi, Texas are described. Operations at the ports of Pecket and Tocopilla in Chile, which had special technical problems, are mentioned. Coal terminals at Port Kembla, Australia and St. Johns River in Florid Jacksonville, Florida are featured as examples of terminals which had to be designed to meet high environmental standards. 13 refs., 2 figs., 14 photos.

  18. The Interplay of Al and Mg Speciation in Advanced Mg Battery Electrolyte Solutions

    Energy Technology Data Exchange (ETDEWEB)

    See, Kimberly A. [Univ. of Illinois, Urbana-Champaign, IL (United States); Chapman, Karena W. [Argonne National Lab. (ANL), Argonne, IL (United States); Zhu, Lingyang [Univ. of Illinois, Urbana-Champaign, IL (United States); Wiaderek, Kamila M. [Argonne National Lab. (ANL), Argonne, IL (United States); Borkiewicz, Olaf J. [Argonne National Lab. (ANL), Argonne, IL (United States); Barile, Christopher J. [Univ. of Illinois, Urbana-Champaign, IL (United States); Chupas, Peter J. [Argonne National Lab. (ANL), Argonne, IL (United States); Gewirth, Andrew A. [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2016-01-13

    Mg batteries are an attractive alternative to Li-based energy storage due to the possibility of higher volumetric capacities with the added advantage of using sustainable materials. A promising emerging electrolyte for Mg batteries is the magnesium aluminum chloride complex (MACC) which shows high Mg electrodeposition and stripping efficiencies and relatively high anodic stabilities. As prepared, MACC is inactive with respect to Mg deposition; however, efficient Mg electrodeposition can be achieved following an electrolytic conditioning process. Through the use of Raman spectroscopy, surface enhanced Raman spectroscopy, 27Al and 35Cl nuclear magnetic resonance spectroscopy, and pair distribution function analysis, we explore the active vs inactive complexes in the MACC electrolyte and demonstrate the codependence of Al and Mg speciation. These techniques report on significant changes occurring in the bulk speciation of the conditioned electrolyte relative to the as-prepared solution. Analysis shows that the active Mg complex in conditioned MACC is very likely the [Mg2(μ–Cl)3·6THF]+ complex that is observed in the solid state structure. Additionally, conditioning creates free Cl– in the electrolyte solution, and we suggest the free Cl– adsorbs at the electrode surface to enhance Mg electrodeposition.

  19. The speciation of elements in incinerator residues and their stabilized products

    International Nuclear Information System (INIS)

    The speciation and solid phase-association of elements in combustion residues has implications for the leachability of residues, the solidification/stabilization (s/s) of residues, and the utilization of residues. In this paper, the authors use a variety of fractionation techniques, bulk analysis and surface microanalysis techniques, and geochemical modeling of leaching of residues to ascertain residue mineralogy, elemental speciation and bonding, and solid phase dissolution. The residues under investigation are a hazardous waste bottom ash (HWBA) and hazardous waste dry lime scrubber residue (HWSR) from a U.S. rotary kiln hazardous waste incinerator; MSW bottom ash (USBA) and MSW dry lime scrubber residue (USSR) from a U.S. mass burn combustor; and MSW ESP ash (CESP) and MSW dry lime scrubber residue (CSR) from a Canadian mass burn combustor. The residues are size reduced (3 or > 2.05 g/cm3), and acid etching are used to concentrate phases into various fractions. Specimens are analyzed in powder form, petrographic 30 μm thin sections, or thin foils

  20. Calculation of structurally related properties of bulk and surface Si

    International Nuclear Information System (INIS)

    The self-consistent pseudopotential method is applied to study the bulk and surface structurally related properties of Si. Equilibrium configurations are determined by minimizing the total energy of the system; the calculated bulk properties and the surface relaxation of Si are found to be in good agreement with experiment. The surface energy and the surface reconstruction of Si are briefly discussed

  1. Sample preparation for arsenic speciation in terrestrial plants--a review.

    Science.gov (United States)

    Amaral, Clarice D B; Nóbrega, Joaquim A; Nogueira, Ana R A

    2013-10-15

    Arsenic is an element widely present in nature. Additionally, it may be found as different species in several matrices and therefore it is one of the target elements in chemical speciation. Although the number of studies in terrestrial plants is low, compared to matrices such as fish or urine, this number is raising due to the fact that this type of matrix are closely related to the human food chain. In speciation analysis, sample preparation is a critical step and several extraction procedures present drawbacks. In this review, papers dealing with extraction procedures, analytical methods, and studies of species conservation in plants cultivated in terrestrial environment are critically discussed. Analytical procedures based on extractions using water or diluted acid solutions associated with HPLC-ICP-MS are good alternatives, owing to their versatility and sensitivity, even though less expensive strategies are shown as feasible choices. PMID:24054594

  2. A review on speciation of iodine-129 in the environmental and biological samples

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Hansen, Violeta; Aldahan, Ala;

    2009-01-01

    As a long-lived beta-emitting radioisotope of iodine, I-129 is produced both naturally and as a result of human nuclear activities. At present time, the main part of I-129 in the environment originates from the human nuclear activity, especially the releases from the spent nuclear fuel reprocessing...... plants, the I-129/I-127 ratios have being reached to values of 10(-10) to 10(-4) in the environment from 10(-12) in the pre-nuclear era. In this article, we review the occurrence, sources, inventory, and concentration level of I-129 in environment and the method for speciation analysis of I-129 in the...... environment. Measurement techniques for the determination of I-129 are presented and compared. An overview of applications of I-129 speciation in various scientific disciplines such as radiation protection, waste depository, and environmental sciences is given. In addition, the bioavailability and radiation...

  3. Chemical Speciation of Long-lived Radionuclide Technetium-99 and its Environmental Behaviour

    DEFF Research Database (Denmark)

    Shi, Keliang

    Because of the high fission yield, high mobility and long half-life, technetium-99 is considered to be one of the most important radionuclides in environmental trace application as well as nuclear waste management. The study on the determination of technetium and its speciation is therefore a key...... issue for understanding its fate and behaviour in ecosystem. This thesis aims to develop series of analytical methods for rapid and accurate determination of total 99Tc in environmental samples (e.g., seaweed, soil, and seawater), as well as speciation analysis of 99Tc in seaweeds. The application of 99...... - sorption at different concentrations of H+ was deduced. With the application of two small TEVA columns (1.5 mL for each), decontamination factors of >104 for molybdenum and >105 for ruthenium and recovery of 60-95% for technetium were achieved for different environmental samples. An absolute detection...

  4. Use of imidazole 4,5-dicarboxylic acid in vanadium speciation

    International Nuclear Information System (INIS)

    A new resin has been synthesized by fictionalization of polystyrene-divinylbenzene (8 %) with imidazole 4,5-dicarboxylic acid through -N=N- bonding. The resulting resin has been characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy, hydrogen ion capacity and metal ion capacity. The speciation study of vanadium has been studied by using this resin and the maximum exchange capacity was found to be 0.45 mmol g-1 for V4+ and that for V5+ was 1.57 mmol g-1 at pH 3 for both. The eluents malonic acid and sodium hydroxide have been used for the selective separation of vanadium(IV) and vanadium(V) species respectively. The effects of diverse ions on the sorption and recovery of each species have been studied. Finally, the developed method has been applied for the speciation and determination of these two species in natural water samples. (author)

  5. Selenium speciation from farm to faeces

    International Nuclear Information System (INIS)

    Full text:The content and speciation of Se were studied in food crops originating from organic and conventional cultivation schemes. Additionally, carrots and onions were biofortified and intrinsically labelled using foliar spraying with isotopically enriched 77SeO3-2. HPLC-ICPMS and HPLC-ESIMS/MS analysis revealed that Se was mainly metabolized to 77SeMet and to Me77SeCys, also in carrot. The 77Se plants were processed to food (50 μg 77Se/d) for a human intervention study. The isotopic enrichment by 77Se as well as 67Zn and 65Cu in urine and faeces was determined by ICP(DRC)MS and the mineral absorption rates estimated. (author)

  6. Competitive speciation in quantitative genetic models.

    Science.gov (United States)

    Drossel, B; Mckane, A

    2000-06-01

    We study sympatric speciation due to competition in an environment with a broad distribution of resources. We assume that the trait under selection is a quantitative trait, and that mating is assortative with respect to this trait. Our model alternates selection according to Lotka-Volterra-type competition equations, with reproduction using the ideas of quantitative genetics. The recurrence relations defined by these equations are studied numerically and analytically. We find that when a population enters a new environment, with a broad distribution of unexploited food sources, the population distribution broadens under a variety of conditions, with peaks at the edge of the distribution indicating the formation of subpopulations. After a long enough time period, the population can split into several subpopulations with little gene flow between them. PMID:10816369

  7. Mercury speciation in the Adriatic Sea.

    Science.gov (United States)

    Kotnik, Jože; Horvat, Milena; Ogrinc, Nives; Fajon, Vesna; Žagar, Dušan; Cossa, Daniel; Sprovieri, Francesca; Pirrone, Nicola

    2015-07-15

    Mercury and its speciation were studied in surface and deep waters of the Adriatic Sea. Several mercury species (i.e. DGM – dissolved gaseous Hg, RHg – reactive Hg, THg – total Hg, MeHg – monomethyl Hg and DMeHg – dimethylmercury) together with other water parameters were measured in coastal and open sea deep water profiles. THg concentrations in the water column, as well as in sediments and pore waters, were the highest in the northern, most polluted part of the Adriatic Sea as the consequence of Hg mining in Idrija and the heavy industry of northern Italy. Certain profiles in the South Adriatic Pit exhibit an increase of DGM just over the bottom due to its diffusion from sediment as a consequence of microbial and/or tectonic activity. Furthermore, a Hg mass balance for the Adriatic Sea was calculated based on measurements and literature data. PMID:26013591

  8. Carbon speciation and surface tension of fog

    Science.gov (United States)

    Capel, P.D.; Gunde, R.; Zurcher, F.; Giger, W.

    1990-01-01

    The speciation of carbon (dissolved/particulate, organic/inorganic) and surface tension of a number of radiation fogs from the urban area of Zurich, Switzerland, were measured. The carbon species were dominated by "dissolved" organic carbon (DOC; i.e., the fraction that passes through a filter), which was typically present at levels of 40-200 mg/L. Less than 10% of the DOC was identified as specific individual organic compounds. Particulate organic carbon (POC) accounted for 26-41% of the mass of the particles, but usually less than 10% of the total organic carbon mass. Inorganic carbon species were relatively minor. The surface tensions of all the measured samples were less than pure water and were correlated with their DOC concentrations. The combination of high DOC and POC and low surface tension suggests a mechanism for the concentration of hydrophobic organic contaminants in the fog droplet, which have been observed by numerous investigators. ?? 1990 American Chemical Society.

  9. Genetic structure and bio-climatic modeling support allopatric over parapatric speciation along a latitudinal gradient

    Directory of Open Access Journals (Sweden)

    Rossetto Maurizio

    2012-08-01

    Full Text Available Abstract Background Four of the five species of Telopea (Proteaceae are distributed in a latitudinal replacement pattern on the south-eastern Australian mainland. In similar circumstances, a simple allopatric speciation model that identifies the origins of genetic isolation within temporal geographic separation is considered as the default model. However, secondary contact between differentiated lineages can result in similar distributional patterns to those arising from a process of parapatric speciation (where gene flow between lineages remains uninterrupted during differentiation. Our aim was to use the characteristic distributional patterns in Telopea to test whether it reflected the evolutionary models of allopatric or parapatric speciation. Using a combination of genetic evidence and environmental niche modelling, we focused on three main questions: do currently described geographic borders coincide with genetic and environmental boundaries; are there hybrid zones in areas of secondary contact between closely related species; did species distributions contract during the last glacial maximum resulting in distributional gaps even where overlap and hybridisation currently occur? Results Total genomic DNA was extracted from 619 individuals sampled from 36 populations representing the four species. Seven nuclear microsatellites (nSSR and six chloroplast microsatellites (cpSSR were amplified across all populations. Genetic structure and the signature of admixture in overlap zones was described using the Bayesian clustering methods implemented in STUCTURE and NewHybrids respectively. Relationships between chlorotypes were reconstructed as a median-joining network. Environmental niche models were produced for all species using environmental parameters from both the present day and the last glacial maximum (LGM. The nSSR loci amplified a total of 154 alleles, while data for the cpSSR loci produced a network of six chlorotypes. STRUCTURE revealed

  10. Nitrogen speciation in mantle and crustal fluids

    Science.gov (United States)

    Li, Yuan; Keppler, Hans

    2014-03-01

    Seventy-nine experiments have been carried out at 600-1400 °C, 2-35 kbar, and oxygen fugacities ranging from the Fe-FeO to the Re-ReO2 buffer to investigate the nitrogen speciation in mantle and crustal N-H-O fluids. Laser Raman analyses of fluid inclusions trapped in situ in quartz and olivine crystals show that N2 and/or NH3 are the only detectable nitrogen species in the fluids at the conditions of the present study. The results further show that in the fluids of the oxidized shallow upper mantle, nitrogen is mostly present as N2, while in the deep reduced upper mantle, NH3 is the dominant nitrogen species. Nitrogen speciation in subduction zone fluids is also calculated from the experimental data to constrain the efficiency of nitrogen recycling. The data show that a hot, oxidized slab is an efficient barrier for deep nitrogen subduction, while a cold, reduced slab would favor recycling nitrogen into the deep mantle. The nitrogen species in magmatic fluids of mid-ocean ridge basalt and arc magmas are predominantly N2, but a significant fraction of nitrogen can be NH3 at certain conditions. The nitrogen species in fluids released from the solidifying magma ocean and the reduced young mantle may have been mostly NH3. The release of such fluids may have created a reduced atmosphere on the every early Earth, with an elevated concentration of NH3. This may not only resolve the faint young Sun paradox but may also have created favorable conditions for the formation of biomolecules through Miller-Urey type reactions.

  11. INORGANIC ARSENIC SPECIATION IN THE ATMOSPHERE: STUDY IN ISFAHAN

    Directory of Open Access Journals (Sweden)

    A KALANTARI

    2000-06-01

    Full Text Available Introduction. Arsenic is one of the most hazardous elements that associate with airborne particulate matter in the atmosphere. Among the different species of arsenic, ASIII has the most toxic and carcinogenic property between any other kind of this element. Arsenic speciation is important in environmental studies. Methods. We collected 59 samples of airborne particulate matter from the atmosphere in Isfahan in a three months period by a high volume air sampler with a flow rate of 1 m3 min-1. Air particulates were collected on the paper filter (Whatman No.41. Four different digestive procedures were examined in order to find the best method. At last we chose digestion of filter with HCI (10-4N due to its feasibility, cost benefit and efficacy. Other methods that examined were digestion of filter with a mixture of HN03 and H2O2, with a mixture of HNO3 and H2O2 and with HCI (1 N. The determination of As3+ and As5+ concentrations were performed by hydrIde generation atomic absorption spectrometry. The effect of Ph on the absorption signal was also investigated in arsenic speciation. Results. Average of total saspended particles (TSP in July, August, and September 1998 were 223, 172, and 247 mg.m3 respectively. The recovery of arsenic from airborne particulate matter was almost the same for the different digestion methods. The concentration and volume of NaBH4 was optimized for determining of different species of arsenic. At pH=5, Asv didn't produce any absorption signal. So, the determination of ASm was carried out easilyat the above mentioned pH. The concentrations of total arsenic were determined in 47 samples. The mean concentrations of total arsenic in July, August and September were 3.31, 2.01 and 2.6, respectively. Discussion. More than 50 percent of total atmospheric arsenic exists as ASIII which is the most toxic and carcinogenic forms of this element. So, it is recommended to make a suitable policy for decreasing of this hazardous

  12. Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses.

    Science.gov (United States)

    Kumpiene, Jurate; Robinson, Ryan; Brännvall, Evelina; Nordmark, Désirée; Bjurström, Henrik; Andreas, Lale; Lagerkvist, Anders; Ecke, Holger

    2011-01-01

    Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment. PMID:20630737

  13. Speciation Analysis of Serum Copper by Ultrafiltration Com-bined with Graphite Furnace Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-Hua; MA Hui-Min; MA Quan-Li; LIANG Shu-Chuan

    2001-01-01

    UItrafiltration combined with graphite furnace atomic absorp-tion spectrometry(GFAAS)was used to study protein binding and speciation of copper in human serum..UItrafiltration was carried out using a cell unit ultrafiltration membraoes having a nominal cut-off of 10,000Dalton.The effects of var-ious experimental factors including the kind and concentration of electrolyte,sample storge,pH,pressure and the precon-ditioning of the membranes on the speciation analysis of serum copper by ultrafiltration were examined.It was observed that 4.5±2.3% of the total copper in serum was ultrafiltrable and this value did not seem to be influenced by the total serum ele-mental concentration,the PH (6.5——10) adn the pressure(≤1.5kg/cm2).the preconditioning of the ultrafiltration system with 0.1mol/L calcium nitrate can overcome the adsorption loss of copper effectively,and the addition of tris-HCI sohtion (pH 7.4)to serum accelerates the ultrafiltration.The present method was proved to be suitable for speciation analysis for its simplicity,rapidity,small sample reuqirement and easy con-trol.The results obtained with the method are accurate and reliable.

  14. Trapped magnetic field between double stacked MgB2 bulks magnetized by pulsed field

    International Nuclear Information System (INIS)

    Pulsed field magnetization (PFM) was performed at Ts=14 K for the double stacked MgB2 bulks (bulk pair) 55 mm diameter fabricated by a reactive liquid Mg infiltration (Mg-RLI) method, compared with that for the single bulk. The trapped field of Bz=0.80 T was achieved between two bulks and Bz at the bulk surface was enhanced from 0.42 T to 0.50 T by stacking of the bulks. The trapped field characteristics of the bulk pair can be qualitatively explained by the model analyses.

  15. Bulk Nuclear Properties from Reactions

    OpenAIRE

    Danielewicz, P.

    2002-01-01

    Extraction of bulk nuclear properties by comparing reaction observables to results from semiclassical transport-model simulations is discussed. Specific properties include the nuclear viscosity, incompressibility and constraints on the nuclear pressure at supranormal densities.

  16. Bulk charges in eleven dimensions

    CERN Document Server

    Hawking, Stephen William

    1998-01-01

    Eleven dimensional supergravity has electric type currents arising from the Chern-Simon and anomaly terms in the action. However the bulk charge integrates to zero for asymptotically flat solutions with topological trivial spatial sections. We show that by relaxing the boundary conditions to generalisations of the ALE and ALF boundary conditions in four dimensions one can obtain static solutions with a bulk charge preserving between 1/16 and 1/4 of the supersymmetries. One can introduce membranes with the same sign of charge into these backgrounds. This raises the possibility that these generalized membranes might decay quantum mechanically to leave just a bulk distribution of charge. Alternatively and more probably, a bulk distribution of charge can decay into a collection of singlely charged membranes. Dimensional reductions of these solutions lead to novel representations of extreme black holes in four dimensions with up to four charges. We discuss how the eleven-dimensional Kaluza-Klein monopole wrapped a...

  17. Speciation of the plutonium at trace levels by capillary electrophoresis-ICP-MS coupling

    International Nuclear Information System (INIS)

    The CE-ICP-MS coupling allowed the development of new analytical methods for the study of plutonium speciation at trace levels including complexation studies of this element by organic and inorganic ligands. First, a method, called dual detection, based on the simultaneous use of the UV-Visible spectrophotometer integrated in the capillary electrophoresis and the ICPMS was developed and validated. It allows the unambiguous determination of electrophoretic mobilities for separated chemical species and gives a powerful tool for speciation studies. Then, the influence on plutonium redox speciation of the buffer from the background electrolyte was evaluated. This study showed the implications of the electrolyte constituents' choice on plutonium redox equilibrium in the sample. Furthermore, the CE-ICP-MS coupling was used for studying the plutonium complexation at trace levels by some organic (NTA and DTPA) and inorganic ligands (carbonates). The behaviour of plutonium valence +III, +IV and +VI was studied in the presence of buffer at near neutral pH. Different species of plutonium were observed depending on the initial oxidation state of the plutonium. This study showed the potential of poly-amino-carboxylic acids, such as NTA and DTPA, for dissolving plutonium precipitates, regardless its initial speciation. Finally, the carbonation of pentavalent neptunium, as an analogue of Pu(V), was achieved at very low concentration of Np (10-8 mol.L-1). The formation constant of NpO2(CO3)- at 25 deg. C and 2,5 x 10-2 mol.L-1 ionic strength was measured by CE-ICP-MS and found to be consistent with literature data. (author)

  18. PARTICLE SPECIATION AND EMISSION PROFILES OF SMALL 2-STROKE ENGINES

    Science.gov (United States)

    The Human Exposure and Atmospheric Sciences Division (HEASD) conducts studies designed to acquire information from emission sources for use in source apportionment studies. The objective of this work is to characterize a complete, speciated emission profile (PM and air toxics) ...

  19. Effect of Deinococcus radiodurans on speciation of radiocesium in soil

    International Nuclear Information System (INIS)

    The chemical speciation of radiocesium which determines its environmental behavior could be affected by microbial processes in soil. However, the speciation of radiocesium in soil has not been well documented. The speciation of radiocesium in soil was investigated with the absence and presence of Deinococcus radiodurans and Pseudomonas sp., respectively. The content of radiocesium in residual phase was increased significantly (p<0.01) with the presence of bacteria in comparison to aseptic control, about 60% of adsorbed radiocesium existed in residual phase with the presence of bacteria. The proportions of radiocesium in different speciation were not significantly changed in the presence of D. radiodurans and Pseudomonas sp. with a longer incubation time. About 67.8% of the total absorbed radiocesium in D. radiodurans cells was extractable with ethanol. (author)

  20. A dynamical theory of speciation on holey adaptive landscapes

    CERN Document Server

    Gavrilets, S

    1998-01-01

    The metaphor of holey adaptive landscapes provides a pictorial representation of the process of speciation as a consequence of genetic divergence. In this metaphor, biological populations diverge along connected clusters of well-fit genotypes in a multidimensional adaptive landscape and become reproductively isolated species when they come to be on opposite sides of a ``hole'' in the adaptive landscape. No crossing of any adaptive valleys is required. I formulate and study a series of simple models describing the dynamics of speciation on holey adaptive landscapes driven by mutation and random genetic drift. Unlike most previous models that concentrate only on some stages of speciation, the models studied here describe the complete process of speciation from initiation until completion. The evolutionary factors included are selection (reproductive isolation), random genetic drift, mutation, recombination, and migration. In these models, pre- and post-mating reproductive isolation is a consequence of cumulativ...

  1. Synchrotron speciation data for zero-valent iron nanoparticles

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data set encompasses a complete analysis of synchrotron speciation data for 5 iron nanoparticle samples (P1, P2, P3, S1, S2, and metallic iron) to include...

  2. Chemical speciation: an instrument for evaluation of mineral bioavailability

    OpenAIRE

    Luana Sarpa Reis; Édira Castello Branco de Andrade Gonçalves

    2015-01-01

    Chemical speciation allows knowing the the different chemical forms of metals in a sample. Sequential extraction procedures are used to evaluate the fractionation of the metals in solid matrices. Few studies are described in the literature related to chemical speciation in food. Residues from fruits and vegetables generated in industry processes results in significant nutritional losses. The nutritional value of a food containing a given mineral depends not only on its content, but also on it...

  3. Chromosomal speciation and molecular divergence - Accelerated evolution in rearranged chromosomes

    OpenAIRE

    Navarro, Arcadi; Barton, Nick

    2003-01-01

    Humans and their closest evolutionary relatives, the chimpanzees, differ in ~1.24% of their genomic DNA sequences. The fraction of these changes accumulated during the speciation processes that have separated the two lineages may be of special relevance in understanding the basis of their differences. We analyzed human and chimpanzee sequence data to search for the patterns of divergence and polymorphism predicted by a theoretical model of speciation. According to the model, positively select...

  4. Doubts about complex speciation between humans and chimpanzees

    OpenAIRE

    Presgraves, Daven C; Yi, Soojin V

    2009-01-01

    Two patterns from large-scale DNA sequence data have been put forward as evidence that speciation between humans and chimpanzees was complex, involving hybridization and strong selection: divergence between humans and chimpanzees varies considerably across the autosomes; and divergence between humans and chimpanzees, but not gorilla, is markedly lower on the X chromosome. Here, we describe how simple speciation and neutral molecular evolution explain both patterns. In particular, the wide ran...

  5. Modes of speciation and the neutral theory of biodiversity

    OpenAIRE

    Etienne, Rampal S.; Apol, M. Emile F.; Olff, Han; Weissing, Franz J.

    2007-01-01

    Hubbell's neutral theory of biodiversity has generated much debate over the need for niches to explain biodiversity patterns. Discussion of the theory has focused on its neutrality assumption, i.e. the functional equivalence of species in competition and dispersal. Almost no attention has been paid to another critical aspect of the theory, the assumptions on the nature of the speciation process. In the standard version of the neutral theory each individual has a fixed probability to speciate....

  6. LJUNGSKILE 1.0 A Computer Program for Investigation of Uncertainties in Chemical Speciation

    International Nuclear Information System (INIS)

    combine the both variables in a way that adequate pH/CO2 partial pressure pairs are matched in the input vectors while LHS does not account for such correlations. Taken the generally rather poor degree of consistency, comparability and completeness in the existent thermodynamic data, however, such argumentation -justified as it is from a fundamental point of view- seems to be premature. It should be mentioned, however, that viable ways to account for correlation in input parameters have been reported in literature. The LJUNGSKILE program is written in C++ using the Borland C++ builder. The program is divided into two major parts. One part containing the chemical calculations and one containing the statistical methods used. The basic idea is to make many runs with PHREEQC and in each run the stability constants of interest are changed slightly within their respective confidence interval according to the statistical method used. Then, after each such cycle, if this option was selected, one of the factors may be changed by given increments to a given level, e.g. changing pH, and thus create a speciation diagram versus pH with uncertainty bands for each species concentration

  7. Effective Pure States for Bulk Quantum Computation

    OpenAIRE

    Knill, Emanuel; Chuang, Isaac; Laflamme, Raymond

    1997-01-01

    In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure expectation values of certain observables with limited sensitivity. The initial state of each computer in the ensemble is known but not pure. Methods for obtaining effective pure input states by a series of manipulations have been described by Gershenfeld and Chuang (logical labeling) and Cory et al. (spatial averaging) for the case of quantum computa...

  8. How humans drive speciation as well as extinction

    Science.gov (United States)

    Maron, M.

    2016-01-01

    A central topic for conservation science is evaluating how human activities influence global species diversity. Humanity exacerbates extinction rates. But by what mechanisms does humanity drive the emergence of new species? We review human-mediated speciation, compare speciation and known extinctions, and discuss the challenges of using net species diversity as a conservation objective. Humans drive rapid evolution through relocation, domestication, hunting and novel ecosystem creation—and emerging technologies could eventually provide additional mechanisms. The number of species relocated, domesticated and hunted during the Holocene is of comparable magnitude to the number of observed extinctions. While instances of human-mediated speciation are known, the overall effect these mechanisms have upon speciation rates has not yet been quantified. We also explore the importance of anthropogenic influence upon divergence in microorganisms. Even if human activities resulted in no net loss of species diversity by balancing speciation and extinction rates, this would probably be deemed unacceptable. We discuss why, based upon ‘no net loss’ conservation literature—considering phylogenetic diversity and other metrics, risk aversion, taboo trade-offs and spatial heterogeneity. We conclude that evaluating speciation alongside extinction could result in more nuanced understanding of biosphere trends, clarifying what it is we actually value about biodiversity. PMID:27358365

  9. Ecological Impacts of Reverse Speciation in Threespine Stickleback.

    Science.gov (United States)

    Rudman, Seth M; Schluter, Dolph

    2016-02-22

    Young species are highly prone to extinction via increased gene flow after human-caused environmental changes [1-6]. This mechanism of biodiversity loss, often termed reverse speciation or introgressive extinction, is of exceptional interest because the parent species are typically highly differentiated ecologically. Reverse speciation events are potentially powerful case studies for the role of evolution in driving ecological changes, as the phenotypic shifts associated with introgressive extinction can be large and they occur over particularly short timescales. Furthermore, reverse speciation can lead to novel phenotypes [1, 2], which may in turn produce novel ecological effects. Here we investigate the ecological shift associated with reverse speciation in threespine stickleback fish using a field study and a replicated experiment. We find that an instance of introgressive extinction had cascading ecological consequences that altered the abundance of both aquatic prey and the pupating aquatic insects that emerged into the terrestrial ecosystem. The community and ecosystem impacts of reverse speciation were novel, and yet they were also predictable based on ecological and morphological considerations. The study suggests that knowledge about the community ecology and changes in functional morphology of a dominant species may lead to some predictive power for the ecological effects of evolutionary change. Moreover, the rapid nature and resultant ecological impacts associated with reverse speciation demonstrates the interplay between biodiversity, evolutionary change, and ecosystem function. PMID:26804556

  10. Speciation Dynamics of Phosphorus during (Hydro)Thermal Treatments of Sewage Sludge.

    Science.gov (United States)

    Huang, Rixiang; Tang, Yuanzhi

    2015-12-15

    (Hydro)thermal treatments of sewage sludge from wastewater treatment process can significantly reduce waste volume and transform sludge into valuable products such as pyrochar and hydrochar. Given the global concern with phosphorus (P) resource depletion, P recycling/reclamation from or direct soil application of the derived chars can be potential P recycling practices. In order to evaluate P recyclability as well as the selection and optimization of treatment techniques, it is critical to understand the effects of different treatment techniques and conditions on P speciation and distribution. In the present study, we systematically characterized P speciation in chars derived from thermal (i.e., pyrolysis) and hydrothermal treatments of municipal sewage sludge using complementary chemical extraction and nuclear magnetic resonance (NMR) spectroscopy methods. P species in the raw activated sludge was dominated by orthophosphate and long-chain polyphosphates, whereas increased amounts of pyrophosphate and short-chain polyphosphates formed after pyrolysis at 250-600 °C. In contrast, hydrothermal treatments resulted in the production of only inorganic orthophosphate in the hydrochar. In addition to the change of molecular speciation, thermal treatments also altered the physical state and extractability of different P species in the pyrochars from pyrolysis, with both total P and polyphosphate being less extractable with increasing pyrolysis temperature. Results from this study suggest that P speciation and availability in sludge-derived chars are tunable by varying treatment techniques and conditions, and provide fundamental knowledge basis for the design and selection of waste management strategies for better nutrient (re)cycling and reclamation. PMID:26633236

  11. Nuclear locus divergence at the early stages of speciation in the Orchard Oriole complex.

    Science.gov (United States)

    Sturge, Rachel J; Cortés-Rodríguez, M Nandadevi; Rojas-Soto, Octavio R; Omland, Kevin E

    2016-07-01

    As two lineages diverge from one another, mitochondrial DNA should evolve fixed differences more rapidly than nuclear DNA due to its smaller effective population size and faster mutation rate. As a consequence, molecular systematists have focused on the criteria of reciprocal monophyly in mitochondrial DNA for delimiting species boundaries. However, mitochondrial gene trees do not necessarily reflect the evolutionary history of the taxa in question, and even mitochondrial loci are not expected to be reciprocally monophyletic when the speciation event happened very recently. The goal of this study was to examine mitochondrial paraphyly within the Orchard Oriole complex, which is composed of Icterus spurius (Orchard Oriole) and Icterus fuertesi (Fuertes' Oriole). We increased the geographic sampling, added four nuclear loci, and used a range of population genetic and coalescent methods to examine the divergence between the taxa. With increased taxon sampling, we found evidence of clear structure between the taxa for mitochondrial DNA. However, nuclear loci showed little evidence of population structure, indicating a very recent divergence between I. spurius and I. fuertesi. Another goal was to examine the genetic variation within each taxon to look for evidence of a past founder event within the I. fuertesi lineage. Based on the high amounts of genetic variation for all nuclear loci, we found no evidence of such an event - thus, we found no support for the possible founding of I. fuertesi through a change in migratory behavior, followed by peripheral isolates speciation. Our results demonstrate that these two taxa are in the earliest stages of speciation, at a point when they have fixed differences in plumage color that are not reflected in monophyly of the mitochondrial or nuclear DNA markers in this study. This very recent divergence makes them ideal for continued studies of species boundaries and the earliest stages of speciation. PMID:27386077

  12. Effects of water management on arsenic and cadmium speciation and accumulation in an upland rice cultivar

    Institute of Scientific and Technical Information of China (English)

    Pengjie Hu; Younan Ouyang; Longhua Wu; Libo Shen; Yongming Luo; Peter Christie

    2015-01-01

    Pot and field experiments were conducted to investigate the effects of water regimes on the speciation and accumulation of arsenic (As) and cadmium (Cd) in Brazilian upland rice growing in soils polluted with both As and Cd.In the pot experiment constant and intermittent flooding treatments gave 3-16 times higher As concentrations in soil solution than did aerobic conditions but Cd showed the opposite trend.Compared to arsenate,there were more marked changes in the arsenite concentrations in the soil solution as water management shifted,and therefore arsenite concentrations dominated the As speciation and bioavailability in the soil.In the field experiment As concentrations in the rice grains increased from 0.14 to 0.21 mg/kg while Cd concentrations decreased from 0.21 to 0.02 mg/kg with increasing irrigation ranging from aerobic to constantly flooding conditions.Among the various water regimes the conventional irrigation treatment produced the highest rice grain yield of 6.29 tons/ha.The As speciation analysis reveals that the accumulation of dimethylarsinic acid (from 11.3% to 61.7%) made a greater contribution to the increase in total As in brown rice in the intermittent and constant flooding treatments compared to the intermittent-aerobic treatment.Thus,water management exerted opposite effects on Cd and As speciation and bioavailability in the soil and consequently on their accumulation in the upland rice.Special care is required when irrigation regime methods are employed to mitigate the accumulation of metal(loid)s in the grain of rice grown in soils polluted with both As and Cd.

  13. Sorption Speciation of Lanthanides/Actinides on Minerals by TRLFS, EXAFS and DFT Studies: A Review

    Directory of Open Access Journals (Sweden)

    Xiaoli Tan

    2010-11-01

    Full Text Available Lanthanides/actinides sorption speciation on minerals and oxides by means of time resolved laser fluorescence spectroscopy (TRLFS, extended X-ray absorption fine structure spectroscopy (EXAFS and density functional theory (DFT is reviewed in the field of nuclear disposal safety research. The theoretical aspects of the methods are concisely presented. Examples of recent research results of lanthanide/actinide speciation and local atomic structures using TRLFS, EXAFS and DFT are discussed. The interaction of lanthanides/actinides with oxides and minerals as well as their uptake are also of common interest in radionuclide chemistry. Especially the sorption and inclusion of radionuclides into several minerals lead to an improvement in knowledge of minor components in solids. In the solid-liquid interface, the speciation and local atomic structures of Eu(III, Cm(III, U(VI, and Np(IV/VI in several natural and synthetic minerals and oxides are also reviewed and discussed. The review is important to understand the physicochemical behavior of lanthanides/actinides at a molecular level in the natural environment.

  14. Coevolution is linked with phenotypic diversification but not speciation in avian brood parasites.

    Science.gov (United States)

    Medina, Iliana; Langmore, Naomi E

    2015-12-22

    Coevolution is often invoked as an engine of biological diversity. Avian brood parasites and their hosts provide one of the best-known examples of coevolution. Brood parasites lay their eggs in the nests of other species, selecting for host defences and reciprocal counteradaptations in parasites. In theory, this arms race should promote increased rates of speciation and phenotypic evolution. Here, we use recently developed methods to test whether the three largest avian brood parasitic lineages show changes in rates of phenotypic diversity and speciation relative to non-parasitic lineages. Our results challenge the accepted paradigm, and show that there is little consistent evidence that lineages of brood parasites have higher speciation or extinction rates than non-parasitic species. However, we provide the first evidence that the evolution of brood parasitic behaviour may affect rates of evolution in morphological traits associated with parasitism. Specifically, egg size and the colour and pattern of plumage have evolved up to nine times faster in parasitic than in non-parasitic cuckoos. Moreover, cuckoo clades of parasitic species that are sympatric (and share similar host genera) exhibit higher rates of phenotypic evolution. This supports the idea that competition for hosts may be linked to the high phenotypic diversity found in parasitic cuckoos. PMID:26702044

  15. Development of the DGT technique for in-situ Pu speciation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cusnir, R.; Bochud, F.; Froidevaux, P. [Institute of Radiation Physics, Lausanne University Hospital, Rue du Grand-Pre 1, CH-1007 Lausanne (Switzerland); Steinmann, P. [Federal Office of Public Health, Swarzenburgstrasse 165, CH-3003 Bern (Switzerland)

    2014-07-01

    Toxic effects of artificial radionuclides are strongly dependent on the surrounding chemical environment which determines the bioavailability of contaminant species. Speciation of plutonium in the environment is of particular interest since it is a long-life actinide contributing to the dose exposure via ingestion with water and food in case of radioactive discharge. Furthermore, natural colloids present in waters, as main carriers of dissolved trace metals, can transport plutonium over significant distances from contaminated sites. The diffusive gradients in thin films (DGT) technique is an efficient instrument for passive sampling of trace metals. It allows for in-situ monitoring of mean concentrations of bioavailable contaminant species (1). A DGT sampler consists of two gel layers: a polyacrylamide hydrogel diffusion layer allowing to diffuse labile metal species to the second, binding layer, impregnated with ion-exchange resin. Resin elution and further analysis allow determining the amount of the bioavailable fraction of trace metals in the bulk solution, which can be calculated from the relationship: C{sub bulk}= (M x Δg)/(D x t x A) where M is the measured metal species inventory in the resin, Δg the thickness of the diffusion layer, D the diffusion coefficient of the species in the gel, t the time of deployment, A the diffusion area. To our knowledge, the DGT has not yet been applied for Pu speciation measurements and the D value is unknown. Here we propose the use of DGT to monitor the dissolved phase and labile complexes of plutonium in the aquatic environment. We have first measured the diffusion coefficient of plutonium in the hydrogel. Experiments were carried out in a diffusion cell (2) and with commercially available DGT samplers exposed in standardized solutions containing {sup 239}Pu at pico-molar concentrations. Both approaches give comparable D values in the range of 2.30 x 10{sup -6} - 2.45 x 10{sup -6} cm{sup 2} s{sup -1}. We then studied

  16. Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

    Directory of Open Access Journals (Sweden)

    Scott J. Markich

    2002-01-01

    Full Text Available The speciation of uranium (U in relation to its bioavailability is reviewed for surface waters (fresh- and seawater and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI is the major form of U in oxic surface waters, while U(IV is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U4+ or UO22+ and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate, and humic substances (HS (e.g., uranyl fulvate in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO22+ and UO2OH+ are the major forms of U(VI available to organisms, rather than U in strong complexes (e.g., uranyl fulvate or adsorbed to colloidal and/or particulate matter. U(VI complexes with inorganic ligands (e.g., carbonate or phosphate and HS apparently reduce the bioavailability of U by reducing the activity of UO22+ and UO2OH+. The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been

  17. Bulk metallic glass for low noise fluxgate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The team of Prime Photonics, Virginia Tech, and Utron Kinetics propose to demonstrate a method for fabrication of a bulk, amorphous, cobalt-rich material that...

  18. Mercury speciation in liquid petroleum product : comparison between on-site approach and lab measurement using size exclusion chromatography with high resolution inductively coupled plasma mass spectrometric detection (SEC-ICP-HR MS).

    OpenAIRE

    Gaulier, Florine; Gibert, Alexandre; Walls, David; Langford, Michael; Baker, Stuart; Baudot, Arnaud; Porcheron, Fabien; Lienmann, Charles-Philippe

    2015-01-01

    The accuracy of two different analytical methods dedicated to the speciation of mercury in liquid hydrocarbons isdiscussed in the present paper. A first step involving the comparison of a modified UOP 938 method—based onfiltration, purge and extraction—with size exclusion chromatography coupled to ICP-HR MS (SEC-ICP-HR MS)was carried out on specific synthetic model mercury compounds. The modified UOP 938 method (defined hereas operational speciation) allowed various mercury compounds to be gr...

  19. Speciation of plutonium during sorption and diffusion in Opalinus clay

    International Nuclear Information System (INIS)

    well as on OPA thin sections and diffusion samples. Pu LIII-edge EXAFS spectra of powder samples showed that an innersphere sorption of Pu(IV) species on OPA surface was formed, independent from the initial Pu oxidation states in solution. By combining the applied spatially resolved methods, it was possible for the first time to determine the elemental distribution of Pu and other elements contained in OPA using μ-XRF. Pu LIII-edge μ-XANES spectra on Pu hot spots of thin sections and diffusion samples confirmed that less mobile Pu(IV) is the dominating species on OPA after sorption and diffusion processes. In addition, for the first time a diffusion profile of Pu in OPA was measured using μ-XRF. The speciation of Pu with μ-XANES showed that Pu(V) was reduced progressively along its diffusion path to Pu(IV). By μ-XRD the clay mineral illite was identified as the main mineral phase in areas where Pu was enriched and iron(II)-bearing siderite could be one of the redox-active mineral phases contained in OPA. The results of this work show that OPA is a suitable option for the geological disposal with regard to the safety of a nuclear repository.

  20. Technetium speciation in radioactive wastes generated in pyrochemical reprocessing

    International Nuclear Information System (INIS)

    Pyrometallurgy of uranium and plutonium in chloride and fluoride molten salts is now intensively studied while little attention is given to the long-lived fission product technetium, which is one of the most hazardous nuclear wastes. Regarding the study of the speciation of technetium-99 in the course of pyrochemical reprocessing of spent nuclear fuel, now considered the most probable alternative approach to reprocessing of spent MOX and high burn-up nuclear fuel, EXAFS measurements were performed at the Rossendorf Beamline (ROBL) on the samples simulating radioactive wastes generated by pyrochemical reprocessing, prepared at UMR5084. During pyrometallurgical spent fuel reprocessing, technetium can remain in the fused salt or enter (depending on the applied temperatures, reagents and oxidative or reducing potentials) either the sedimented phase, contaminating Pu-enriched phase or the electrodeposited U phase. The Tc phase could not be detected by means of X-ray diffraction either in the sediment or in the deposit. The Tc phase is finely dispersed and X-ray amorphous. There are some data showing that technetium in such matrix forms not only a hexagonal but also a metastable cubic lattice with higher chemical reactivity. Therefore, it is very important to develop methods of analyses like EXAFS that allow to determine the Tc speciation in such samples. Our results show that under conditions when chlorine or oxygen could be formed or injected into the melt, Tc can also form several oxides, oxychlorides and chlorides of different but rather high volatility, turning on an important polluting risk linked to gas-off. The available EXAF spectra of technetium species are fragmentary and do not present the whole of the species possible under pyrometallurgy conditions. Some recent studies gave indications on the presence of unknown Tc chloride complexes. It was of high importance to carry out synthetic work to supply a large set of technetium compounds in the closed containers

  1. Induction detection of concealed bulk banknotes

    International Nuclear Information System (INIS)

    Bulk cash smuggling is a serious issue that has grown in volume in recent years. By building on the magnetic characteristics of paper currency, induction sensing is found to be capable of quickly detecting large masses of banknotes. The results show that this method is effective in detecting bulk cash through concealing materials such as plastics, cardboards, fabrics and aluminum foil. The significant difference in the observed phase between the received signals caused by conducting materials and ferrite compounds, found in banknotes, provides a good indication that this process can overcome the interference by metal objects in a real sensing application. This identification strategy has the potential to not only detect the presence of banknotes, but also the number, while still eliminating false positives caused by metal objects

  2. Surface-Bulk Vibrational Correlation Spectroscopy.

    Science.gov (United States)

    Roy, Sandra; Covert, Paul A; Jarisz, Tasha A; Chan, Chantelle; Hore, Dennis K

    2016-05-01

    Homo- and heterospectral correlation analysis are powerful methods for investigating the effects of external influences on the spectra acquired using distinct and complementary techniques. Nonlinear vibrational spectroscopy is a selective and sensitive probe of surface structure changes, as bulk molecules are excluded on the basis of symmetry. However, as a result of this exquisite specificity, it is blind to changes that may be occurring in the solution. We demonstrate that correlation analysis between surface-specific techniques and bulk probes such as infrared absorption or Raman scattering may be used to reveal additional details of the adsorption process. Using the adsorption of water and ethanol binary mixtures as an example, we illustrate that this provides support for a competitive binding model and adds new insight into a dimer-to-bilayer transition proposed from previous experiments and simulations. PMID:27058265

  3. Bulk Viscosity of Interacting Hadrons

    OpenAIRE

    Wiranata, A.; M. Prakash

    2009-01-01

    We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature ari...

  4. Bulk Viscosity of Interacting Hadrons

    CERN Document Server

    Wiranata, A

    2009-01-01

    We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature arise from particles which are neither extremely nonrelativistic nor extremely relativistic. Numerical results for a model binary mixture are reported.

  5. Renormalization group approach to causal bulk viscous cosmological models

    Energy Technology Data Exchange (ETDEWEB)

    Belinchon, J A [Grupo Inter-Universitario de Analisis Dimensional, Dept. Fisica ETS Arquitectura UPM, Av. Juan de Herrera 4, Madrid (Spain); Harko, T [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Mak, M K [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong (China)

    2002-06-07

    The renormalization group method is applied to the study of homogeneous and flat Friedmann-Robertson-Walker type universes, filled with a causal bulk viscous cosmological fluid. The starting point of the study is the consideration of the scaling properties of the gravitational field equations, the causal evolution equation of the bulk viscous pressure and the equations of state. The requirement of scale invariance imposes strong constraints on the temporal evolution of the bulk viscosity coefficient, temperature and relaxation time, thus leading to the possibility of obtaining the bulk viscosity coefficient-energy density dependence. For a cosmological model with bulk viscosity coefficient proportional to the Hubble parameter, we perform the analysis of the renormalization group flow around the scale-invariant fixed point, thereby obtaining the long-time behaviour of the scale factor.

  6. Renormalization group approach to causal bulk viscous cosmological models

    International Nuclear Information System (INIS)

    The renormalization group method is applied to the study of homogeneous and flat Friedmann-Robertson-Walker type universes, filled with a causal bulk viscous cosmological fluid. The starting point of the study is the consideration of the scaling properties of the gravitational field equations, the causal evolution equation of the bulk viscous pressure and the equations of state. The requirement of scale invariance imposes strong constraints on the temporal evolution of the bulk viscosity coefficient, temperature and relaxation time, thus leading to the possibility of obtaining the bulk viscosity coefficient-energy density dependence. For a cosmological model with bulk viscosity coefficient proportional to the Hubble parameter, we perform the analysis of the renormalization group flow around the scale-invariant fixed point, thereby obtaining the long-time behaviour of the scale factor

  7. The use of ion chromatography-dc plasma atomic emission spectrometry for the speciation of trace metals

    Energy Technology Data Exchange (ETDEWEB)

    Urasa, I.T.

    1991-09-20

    The original objects of this research program were: to interface d.c. plasma atomic emission spectrometer with an ion chromatograph; to characterize and optimize the combined systems for application in the speciation of metals in aqueous solutions; to use this system in the study of the solution chemistry of various metals; and to find ways in which the measurement sensitivity of the method can be enhanced, thereby allowing the detection of metal species at low ppb concentration levels. This approach has been used to study the chemistry of and speciate several elements in solution including: arsenic, chromium, iron, manganese, nickel phosphorus, platinum, selenium, and vanadium. During the course of this research, we have found that the solution chemistry of the elements studied and the speciation data obtained can vary considerably depending on the solution, and the chromatographic conditions employed. The speciation of chromium, iron, and vanadium was found to be highly influenced by the acidity of the sample. The element selective nature of the d.c. plasma detector allows these changes to be monitored, thereby providing quantitative information on the new moieties formed. New approaches are being developed including the use of chelating ligands as preconcentration agents for purposes of reducing further the detection limits of the elements of interest and to improve the overall element speciation scheme. New thrusts are being directed towards the employment of post-column derivatization method coupled with colorimetric measurements to detect and quantify metal species eluting from the chromatographic column. The influence of sample acidity on these investigations will be carefully evaluated. These new thrusts are described in the accompanying Project Renewal Proposal.

  8. Analysis and speciation of the tritium in environmental matrices

    International Nuclear Information System (INIS)

    This study deals with environmental monitoring. The main aims are (i) the optimisation of the analytical procedure for the tritium in organic form determination, and (ii) the identification of the tritium bearing molecules which are responsible for its transfer from the environment to man. The study was divided into three stages. First an analytical method was developed to determine hydrogen content of several samples, which is a key element to calculate accurate organically bound tritium activities. Secondly, the impact of the organically bound tritium fractions separation (labile exchange) for the determination of the representative fraction of the level of environmental tritium activity was then evaluated. For that, the amount of solubilised sample was estimated. Finally, the speciation of tritium in environmental samples was investigated. Several molecules classes and organic compounds dissolved in the labile exchanges solvent were identified. The results show that the distribution of tritium in organisms depends on both properties of the chemical bond in which it is involved and chemical properties of tritium bearing molecules. The identified compounds belong to the molecules classes such as carbohydrates or amino acids, constitutive of living organisms. It would now be of interest to study the tritium distribution in an environmental sample to target molecules of interest and study the impact of tritium from the environment to man. (author)

  9. Iodine speciation in edible seaweed by HPLC-ICP-MS

    International Nuclear Information System (INIS)

    Complete text of publication follows. The widespread use of seaweed as food makes necessary more knowledge on their composition. It is well known that seaweed concentrate high amounts of iodine and some papers report that most of it, is present as iodide [M. Shah et al., J. Anal. At. Spectrom., 20 (2005) 176-182]. Nevertheless, there is still a lack of information on the different iodine species that seaweed contain, which is important as bioavailability of this essential element depends on the species. This work deals with the development of a speciation method for iodine in seaweed. Four iodine species: iodide, iodate, monoiodo tyrosine and diiodo tyrosine, have been separated by ion exchange chromatography and have been detected by inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The separation has been achieved in the anion-exchange column IonPac AS7 and the guard column AG7 (Dionex) thermostatically controlled at 20 deg C, using 175 mM ammonium nitrate with 5% acetonitrile as mobile phase. Tellurium was the internal standard. Extracts of eight types of edible seaweed have been injected presenting very different chromatographic profiles. The microscopic seaweed Spirulina platensis was the only one that presented iodide as the only species, while the rest have shown many peaks. The brown seaweed Kombu (Laminaria ochroleuca), the type with the highest total iodine concentration (between 3700 and 6800 μg x g-1 dry weight) was by far the sample with the highest number of species.

  10. Chemical speciation analysis and environmental behaviour of 127I and 12

    International Nuclear Information System (INIS)

    lower adsorption capacity of inorganic and organic iodine species. Adsorption of iodine species onto activated charcoal and DEAE 32 cellulose from seawater samples shows that only about 10% of the total iodine in seawater can be adsorbed onto those materials. Adsorption of iodine species from water samples onto activated charcoal/DEAE is not a suitable method for quantifying the total iodine in freshwater and seawater. An investigation was conducted in order to decompose organic iodine using K2S2O8 in water samples for developing a method for quantification of aquatic organic iodine (129I and 127I). The results show that iodine was quantitatively removed even when the concentration of organic iodine compounds in the studied sample was very high. Due to this, oxidation of iodine organic matter by using K2S2O8 followed by reduction of iodine species and precipitation with silver can be a potential method for determination of total iodine in fresh water samples. An improvement was made of the method for 129I and 127I speciation analysis in soil and sediment samples involving the extraction and fractionation of organic matter. The improved method was further used for the partitioning of 127I and 129I in marine sediments and soils. Sequential extraction results point out that partitioning of 127I and 129I within the organic fraction in soil and marine sediments is controlled by pH conditions where pH values below 5.0-5.5 promote occurrence of 127I and 129I in the humic acid, while at pH > 6 the partitioning was in the fulvic acid fraction. Anoxic conditions seemed to increase the mobility and availability of iodine compared to oxic, while suboxic conditions (soils) reduced the availability of the water soluble fraction compared to the subaqueous (marine) one. The distribution of 129I/127I values differed significantly between phases and samples, indicating that equilibrium with stable iodine have not yet been reached for a large fraction of the released 129I. This means that

  11. Diagnosis of mediastinal bulk disease in Hodgkin patients

    International Nuclear Information System (INIS)

    The radiographic determination of mediastinal bulk in Hodgkin disease is confusing, with numerous methods having been proposed. The authors have evaluated with chest radiography and thoracic CT 76 patients with mediastinal Hodgkin disease. Seventy-four (97%) had bulk disease as determined by at least one method. Patients were categorized according to clinical stage and symptoms, the pattern of nodal involvement, the presence of extension (E disease), and response to treatment; a subset of 37 patients was isolated. These individuals had radiographically and clinically more severe disease that responded less favorably to treatment.The average mediastinal mass diameter in these patients was 11.0 cm, the thoracic ratio 36.6%, and the tumor area 138 cm2. However, no method currently used to define bulk disease would consistently define all of these 37 patients with a poorer prognosis and outcome. The radiographic diagnosis of mediastinal bulk disease in patients with newly diagnosed Hodgkin disease should be done with caution

  12. Bulk charges in eleven dimensions

    Science.gov (United States)

    Hawking, S. W.; Taylor-Robinson, M. M.

    1998-07-01

    Eleven dimensional supergravity has electric type currents arising from the Chern-Simon and anomaly terms in the action. However the bulk charge integrates to zero for asymptotically flat solutions with topological trivial spatial sections. We show that by relaxing the boundary conditions to generalisations of the ALE and ALF boundary conditions in four dimensions one can obtain static solutions with a bulk charge. Solutions involving anomaly terms preserve between 1/16 and 1/4 of the supersymmetries but Chern-Simons fluxes generally break all of the remaining supersymmetry. One can introduce membranes with the same sign of charge into these backgrounds. This raises the possibility that these generalized membranes might decay quantum mechanically to leave just a bulk distribution of charge. Alternatively and more probably, a bulk distribution of charge can decay into a collection of singly charged membranes. Dimensional reductions of these solutions lead to novel representations of extreme black holes in four dimensions with up to four charges. We discuss how the eleven-dimensional Kaluza-Klein monopole wrapped around a space with non-zero first Pontryagin class picks up an electric charge proportional to the Pontryagin number.

  13. Bulk viscosity and deflationary universes

    CERN Document Server

    Lima, J A S; Waga, I

    2007-01-01

    We analyze the conditions that make possible the description of entropy generation in the new inflationary model by means of a nearequilibrium process. We show that there are situations in which the bulk viscosity cannot describe particle production during the coherent field oscillations phase.

  14. Longitudinal bulk acoustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja;

    2009-01-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise i...

  15. Integration of bulk piezoelectric materials into microsystems

    Science.gov (United States)

    Aktakka, Ethem Erkan

    Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200°C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with properties of bulk-PZT5A are mostly preserved without any necessity of repolarization. Three generations of resonant vibration energy harvesters are designed, simulated and fabricated to demonstrate the competitive performance of the new fabrication process over traditional piezoelectric deposition systems. An unpackaged PZT/Si unimorph harvester with 27mm3 active device volume produces up to 205microW at 1.5g/154Hz. The prototypes have achieved the highest figure-of-merits (normalized-power-density x bandwidth) amongst previously reported inertial energy harvesters. The fabricated energy harvester is

  16. A modelling exercise on the importance of ternary alkaline earth carbonate species of uranium(VI) in the inorganic speciation of natural waters

    International Nuclear Information System (INIS)

    Highlights: • The U(VI) speciation in natural waters has been modelled through a modelling exercise. • The results evidence the importance of alkaline earth U(VI) carbonate complexes. • Possible solubility-controlling phases were reported and discussed. • The differences were related to the choice and reliability of thermodynamic data. • Databases need to be improved for reliable U(VI) speciation calculations. - Abstract: Predictive modelling of uranium speciation in natural waters can be achieved using equilibrium thermodynamic data and adequate speciation software. The reliability of such calculations is highly dependent on the equilibrium reactions that are considered as entry data, and the values chosen for the equilibrium constants. The working group “Speciation” of the CETAMA (Analytical methods establishment committee of the French Atomic Energy commission, CEA) has organized a modelling exercise, including four participants, in order to compare modellers’ selections of data and test thermodynamic data bases regarding the calculation of U(VI) inorganic speciation. Six different compositions of model waters were chosen so that to check the importance of ternary alkaline earth carbonate species of U(VI) on the aqueous speciation, and the possible uranium solid phases as solubility-limiting phases. The comparison of the results from the participants suggests (i) that it would be highly valuable for end-users to review thermodynamic constants of ternary carbonate species of U(VI) in a consistent way and implement them in available speciation data bases, and (ii) stresses the necessary care when using data bases to avoid biases and possible erroneous calculations

  17. Sexual selection drives speciation in an Amazonian frog

    Science.gov (United States)

    Boul, K.E.; Funk, W.C.; Darst, C.R.; Cannatella, D.C.; Ryan, M.J.

    2007-01-01

    One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation. Despite the appeal of this hypothesis, evidence for it remains inconclusive. Here, we present several lines of evidence that sexual selection is driving behavioural isolation and speciation among populations of an Amazonian frog (Physalaemus petersi). First, sexual selection has promoted divergence in male mating calls and female preferences for calls between neighbouring populations, resulting in strong behavioural isolation. Second, phylogenetic analysis indicates that populations have become fixed for alternative call types several times throughout the species' range, and coalescent analysis rejects genetic drift as a cause for this pattern, suggesting that this divergence is due to selection. Finally, gene flow estimated with microsatellite loci is an average of 30 times lower between populations with different call types than between populations separated by a similar geographical distance with the same call type, demonstrating genetic divergence and incipient speciation. Taken together, these data provide strong evidence that sexual selection is driving behavioural isolation and speciation, supporting sexual selection as a cause for speciation in the wild. ?? 2006 The Royal Society.

  18. Analytical tools for speciation in the field of toxicology

    International Nuclear Information System (INIS)

    The knowledge of the speciation of elements at trace and ultra-trace level, in biological and environmental media is essential to acquire a better understanding of the mechanisms of toxicity, transport and accumulation in which they are involved. Determining the speciation of an element in a given medium is challenging and requires the knowledge of different methodological approaches: the calculation approach and the experimental approach through the use of dedicated analytical and spectroscopic tools. In this framework, this mini-review reports the approaches to investigate the speciation of elements in biological and environmental media as well as the experimental techniques of speciation analysis, illustrated by recent examples. The main analytical and spectroscopic techniques to obtain structural, molecular, elemental and isotopic information are described. A brief overview of separation techniques coupled with spectrometric techniques is given. Imaging and micro-localisation techniques, which aim at determining the in situ spatial distribution of elements and molecules in various solid samples, are also presented. The last part deals with the development of micro-analytical systems, since they open crucial perspectives to speciation analysis for low sample amounts and analysis on field. (orig.)

  19. Host shift and speciation in a coral-feeding nudibranch.

    Science.gov (United States)

    Faucci, Anuschka; Toonen, Robert J; Hadfield, Michael G

    2007-01-01

    While the role of host preference in ecological speciation has been investigated extensively in terrestrial systems, very little is known in marine environments. Host preference combined with mate choice on the preferred host can lead to population subdivision and adaptation leading to host shifts. We use a phylogenetic approach based on two mitochondrial genetic markers to disentangle the taxonomic status and to investigate the role of host specificity in the speciation of the nudibranch genus Phestilla (Gastropoda, Opisthobranchia) from Guam, Palau and Hawaii. Species of the genus Phestilla complete their life cycle almost entirely on their specific host coral (species of Porites, Goniopora and Tubastrea). They reproduce on their host coral and their planktonic larvae require a host-specific chemical cue to metamorphose and settle onto their host. The phylogenetic trees of the combined cytochrome oxidase I and ribosomal 16S gene sequences clarify the relationship among species of Phestilla identifying most of the nominal species as monophyletic clades. We found a possible case of host shift from Porites to Goniopora and Tubastrea in sympatric Phestilla spp. This represents one of the first documented cases of host shift as a mechanism underlying speciation in a marine invertebrate. Furthermore, we found highly divergent clades within Phestilla sp. 1 and Phestilla minor (8.1-11.1%), suggesting cryptic speciation. The presence of a strong phylogenetic signal for the coral host confirms that the tight link between species of Phestilla and their host coral probably played an important role in speciation within this genus. PMID:17134995

  20. Statistical Determination of Bulk Flow Motions

    CERN Document Server

    Song, Yong-Seon; Nichol, Robert C; Miller, Christopher J

    2010-01-01

    We present here a new parameterization for the bulk motions of galaxies and clusters (in the linear regime) that can be measured statistically from the shape and amplitude of the two-dimensional two-point correlation function. We further propose the one-dimensional velocity dispersion (v_p) of the bulk flow as a complementary measure of redshift-space distortions, which is model-independent and not dependent on the normalisation method. As a demonstration, we have applied our new methodology to the C4 cluster catalogue constructed from Data Release Three (DR3) of the Sloan Digital Sky Survey. We find v_p=270^{+433}km/s (also consistent with v_p=0) for this cluster sample (at z=0.1), which is in agreement with that predicted for a WMAP5-normalised LCDM model (i.e., v_p(LCDM=203km/s). This measurement does not lend support to recent claims of excessive bulk motions (\\simeq1000 km/s) which appear in conflict with LCDM, although our large statistical error cannot rule them out. From the measured coherent evolutio...