Sample records for absorption spectrometry cv-aas

  1. Determination of mercury in hair: Comparison between gold amalgamation-atomic absorption spectrometry and mass spectrometry.

    PubMed

    Domanico, Francesco; Forte, Giovanni; Majorani, Costanza; Senofonte, Oreste; Petrucci, Francesco; Pezzi, Vincenzo; Alimonti, Alessandro

    2017-09-01

    Mercury is a heavy metal that causes serious health problems in exposed subjects. The most toxic form, i.e., methylmercury (MeHg), is mostly excreted through human hair. Numerous analytical methods are available for total Hg analysis in human hair, including cold vapour atomic fluorescence spectrometry (CV-AFS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). The aim of the study was to compare the TDA-AAS with the ICP-MS in the Hg quantification in human hair. After the washing procedure to minimize the external contamination, from each hair sample two aliquots were taken; the first was used for direct analysis of Hg by TDA-AAS and the second was digested for Hg determination by the ICP-MS. Results indicated that the two data sets were fully comparable (median; TDA-AAS, 475ngg -1 ; ICP-MS, 437ngg -1 ) and were not statistically different (Mann-Whitney test; p=0.44). The two techniques presented results with a good coefficient of correlation (r=0.94) despite different operative ranges and method limits. Both techniques satisfied internal performance requirements and the parameters for method validation resulting sensitive, precise and reliable. Finally, the use of the TDA-AAS can be considered instead of the ICP-MS in hair analysis in order to reduce sample manipulation with minor risk of contamination, less time consuming due to the absence of the digestion step and cheaper analyses. Copyright © 2016 Elsevier GmbH. All rights reserved.

  2. ICP OES and CV AAS in determination of mercury in an unusual fatal case of long-term exposure to elemental mercury in a teenager.

    PubMed

    Lech, Teresa

    2014-04-01

    In this work, a case of deliberate self-poisoning is presented. A 14-year-old girl suddenly died during one of the several hospitalizations. Abdominal computer tomography showed a large number of metallic particles in the large intestine. Analysis of blood and internal organs for mercury and other toxic metals carried out by inductively coupled plasma optical emission spectrometry (ICP OES) revealed high concentrations of mercury in kidneys and liver (64,200 and 2470ng/g, respectively), less in stomach (90ng/g), and none in blood. Using cold vapor-atomic absorption spectrometry (CV AAS), high levels of mercury were confirmed in all examined materials, including blood (87ng/g), and additionally in hair. The results of analysis obtained by two techniques revealed that the exposure to mercury was considerable (some time later, it was stated that the mercury originated from thermometers that had been broken over the course of about 1 year, because of Münchausen syndrome). CV AAS is a more sensitive technique, particularly for blood samples (negative results using ICP OES), and tissue samples - with LOQ: 0.63ng/g of Hg (CV AAS) vis-à-vis 70ng/g of Hg (ICP OES). However, ICP OES may be used as a screening technique for autopsy material in acute poisoning by a heavy metal, even one as volatile as mercury. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Interference of nitrite and nitrogen dioxide on mercury and selenium determination by chemical vapor generation atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Nunes, Dayana Lopes; dos Santos, Eliane Pereira; Barin, Juliano Smanioto; Mortari, Sergio Roberto; Dressler, Valderi Luiz; de Moraes Flores, Érico Marlon

    2005-06-01

    In this study, a systematic investigation was performed concerning the interference of nitrogen oxides on the determination of selenium and mercury by hydride generation atomic absorption spectrometry (HG AAS) and cold vapor atomic absorption spectrometry (CV AAS). The effect of nitrate, nitrite and NO 2 dissolved in the condensed phase was evaluated. No effect of NO 3- on Se and Hg determination was observed up to 100 mg of sodium nitrate added to the reaction vessel. The Se signal was reduced by about 80% upon the addition of 6.8 mg NO 2-. For Hg, no interference of nitrite was observed up to 20 mg of NO 2-. A complete suppression of the Se signal was observed when gaseous NO 2 was introduced into analytical solutions. For Hg, a signal decrease between 8 and 13% occurred. For Se, bubbling argon or heating the solution was not able to recover the original absorbance values, whereas Hg signals were recovered with these procedures. When gaseous NO 2 was passed directly into the atomizer, Se signals decreased similarly to when NO 2 was bubbled in analytical solutions. The addition of urea, hydroxylamine hydrochloride and sulfamic acid (SA) was investigated to reduce the NO 2 effect in sample digests containing residual NO 2, but only SA was effective in reducing the interference. Based on the results, it is possible to propose the use of SA to prevent interferences in Se and Hg determinations by HG AAS and CV AAS, respectively.

  4. Paleodiet characterisation of an Etrurian population of Pontecagnano (Italy) by Isotope Ratio Mass Spectrometry (IRMS) and Atomic Absorption Spectrometry (AAS)(#).

    PubMed

    Scarabino, Carla; Lubritto, Carmine; Proto, Antonio; Rubino, Mauro; Fiengo, Gilda; Marzaioli, Fabio; Passariello, Isabella; Busiello, Gaetano; Fortunato, Antonietta; Alfano, Davide; Sabbarese, Carlo; Rogalla, Detlef; De Cesare, Nicola; d'Onofrio, Antonio; Terrasi, Filippo

    2006-06-01

    Human bones recovered from the archaeological site of Pontecagnano (Salerno, Italy) have been studied to reconstruct the diet of an Etrurian population. Two different areas were investigated, named Library and Sant' Antonio, with a total of 44 tombs containing human skeletal remains, ranging in age from the 8th to the 3rd century B.C. This time span was confirmed by 14C dating obtained using Accelerator Mass Spectrometry (AMS) on one bone sample from each site. Atomic Absorption Spectrometry (AAS) was used to extract information about the concentration of Sr, Zn, Ca elements in the bone inorganic fraction, whilst stable isotope ratio measurements (IRMS) were carried out on bone collagen to obtain the delta13C and delta15N. A reliable technique has been used to extract and separate the inorganic and organic fractions of the bone remains. Both IRMS and AAS results suggest a mixed diet including C3 plant food and herbivore animals, consistent with archaeological indications.

  5. DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION

    EPA Science Inventory

    A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and
    compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), mill...

  6. COMPREHENSIVE ANALYSIS OF BIOLOGICALLY RELEVANT ARSENICALS BY PH-SELECTIVE HYDRIDE GENERATION-ATOMIC ABSORPTION SPECTROMETRY

    EPA Science Inventory


    A method based on pH-selective generation and separation of arsines is commonly used for analysis of inorganic, methylated, and dimethylated trivalent and pentavalent arsenicals by hydride generation-atomic absorption spectrometry (HG-AAS). We have optimized this method to pe...

  7. The role of atomic absorption spectrometry in geochemical exploration

    USGS Publications Warehouse

    Viets, J.G.; O'Leary, R. M.

    1992-01-01

    In this paper we briefly describe the principles of atomic absorption spectrometry (AAS) and the basic hardware components necessary to make measurements of analyte concentrations. Then we discuss a variety of methods that have been developed for the introduction of analyte atoms into the light path of the spectrophotometer. This section deals with sample digestion, elimination of interferences, and optimum production of ground-state atoms, all critical considerations when choosing an AAS method. Other critical considerations are cost, speed, simplicity, precision, and applicability of the method to the wide range of materials sampled in geochemical exploration. We cannot attempt to review all of the AAS methods developed for geological materials but instead will restrict our discussion to some of those appropriate for geochemical exploration. Our background and familiarity are reflected in the methods we discuss, and we have no doubt overlooked many good methods. Our discussion should therefore be considered a starting point in finding the right method for the problem, rather than the end of the search. Finally, we discuss the future of AAS relative to other instrumental techniques and the promising new directions for AAS in geochemical exploration. ?? 1992.

  8. Determination of tetraalkyllead compounds in gasoline by liquid chromatography-atomic absorption spectrometry

    USGS Publications Warehouse

    Messman, J.D.; Rains, T.C.

    1981-01-01

    A liquid chromatography-atomic absorption spectrometry (LC-AAS) hybrid analytical technique is presented for metal speciation measurements on complex liquid samples. The versatility and inherent metal selectivity of the technique are Illustrated by the rapid determination of five tetraalkyllead compounds in commercial gasoline. Separation of the individual tetraalkyllead species is achieved by reversed-phase liquid chromatography using an acetonitrile/water mobile phase. The effluent from the liquid Chromatograph Is introduced directly into the aspiration uptake capillary of the nebulizer of an air/acetylene flame atomic absorption spectrometer. Spectral interferences due to coeluting hydrocarbon matrix constituents were not observed at the 283.3-nm resonance line of lead used for analysis. Detection limits of this LC-AAS hydrid analytical technique, based on a 20-??L injection, are approximately 10 ng Pb for each tetraalkyllead compound.

  9. Multivessel system for cold-vapor mercury generation. Determination of mercury in hair and fish.

    PubMed

    Boaventura, G R; Barbosa, A C; East, G A

    1997-01-01

    A multivessel system for the determination of mercury (Hg) by cold-vapor atomic absorption spectrometry (CV-AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed. The performance of the proposed device was tested by determining total Hg in quality-control samples of hair and fishes following acid digestion. Application of the apparatus to the determination of Hg by CV-AAS following alkaline digestion was studied as well. The detection limit obtained for CV-AAS was 0.11 ng/mL and for ICP-AES 1.39 ng/mL. The results show that the system is appropriate to be used in techniques involving cold-vapor generation of Hg.

  10. Direct determination of Pb in raw milk by graphite furnace atomic absorption spectrometry (GF AAS) with electrothermal atomization sampling from slurries.

    PubMed

    de Oliveira, Tatiane Milão; Augusto Peres, Jayme; Lurdes Felsner, Maria; Cristiane Justi, Karin

    2017-08-15

    Milk is an important food in the human diet due to its physico-chemical composition; therefore, it is necessary to monitor contamination by toxic metals such as Pb. Milk sample slurries were prepared using Triton X-100 and nitric acid for direct analysis of Pb using graphite furnace atomic absorption spectrometry - GF AAS. After dilution of the slurries, 10.00µl were directly introduced into the pyrolytic graphite tube without use of a chemical modifier, which acts as an advantage considering this type of matrix. The limits of detection and quantification were 0.64 and 2.14µgl -1 , respectively. The figures of merit studied showed that the proposed methodology without pretreatment of the raw milk sample and using external standard calibration is suitable. The methodology was applied in milk samples from the Guarapuava region, in Paraná State (Brazil) and Pb concentrations ranged from 2.12 to 37.36µgl -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Mercury in Environmental and Biological Samples Using Online Combustion with Sequential Atomic Absorption and Fluorescence Measurements: A Direct Comparison of Two Fundamental Techniques in Spectrometry

    ERIC Educational Resources Information Center

    Cizdziel, James V.

    2011-01-01

    In this laboratory experiment, students quantitatively determine the concentration of an element (mercury) in an environmental or biological sample while comparing and contrasting the fundamental techniques of atomic absorption spectrometry (AAS) and atomic fluorescence spectrometry (AFS). A mercury analyzer based on sample combustion,…

  12. Design considerations regarding an atomizer for multi-element electrothermal atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Katskov, Dmitri A.; Sadagov, Yuri M.

    2011-06-01

    Flame AAS with primary line source that is 50-1000 times higher than the limits obtainable with common ETAAS (Electrothermal Atomic Absorption Spectrometry) instrumentation.

  13. The determination of mercury in mushrooms by CV-AAS and ICP-AES techniques.

    PubMed

    Jarzynska, Grazyna; Falandysz, Jerzy

    2011-01-01

    This research presents an example of an excellent applied study on analytical problems due to hazardous mercury determination in environmental materials and validity of published results on content of this element in wild growing mushrooms. The total mercury content has been analyzed in a several species of wild-grown mushrooms and some herbal origin certified reference materials, using two analytical methods. One method was commonly known and well validated the cold-vapour atomic absorption spectroscopy (CV-AAS) after a direct sample pyrolysis coupled to the gold wool trap, which was a reference method. A second method was a procedure that involved a final mercury measurement using the inductively-coupled plasma atomic emission spectroscopy (ICP-AES) at λ 194.163 nm, which was used by some authors to report on a high mercury content of a large sets of wild-grown mushrooms. We found that the method using the ICP-AES at λ 194.163 nm gave inaccurate and imprecise results. The results of this study imply that because of unsuitability of total mercury determination using the ICP-AES at λ 194.163 nm, the reports on great concentrations of this metal in a large sets of wild-grown mushrooms, when examined using this method, have to be studied with caution, since data are highly biased.

  14. Application of thermospray flame furnace atomic absorption spectrometry for investigation of silver nanoparticles.

    PubMed

    Sirirat, Natnicha; Tetbuntad, Kornrawee; Siripinyanond, Atitaya

    2017-03-01

    Thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was applied to investigate the time-dependent absorption peak profile of various forms of silver. The thermospray flame furnace was set up with a 10-cm-long nickel tube with six holes, each 2.0 mm in diameter, to allow the flame to enter, and this nickel tube acted as a furnace. A sample of 300 μL was introduced into this furnace by use of water as a carrier at a flow rate of 0.5 mL min -1 through the ceramic capillary (0.5-mm inner diameter and 2.0-mm outer diameter), which was inserted into the front hole of the nickel tube. The system was applied to examine atomization behaviors of silver nanoparticles (AgNPs) with particle sizes ranging from 10 to 100 nm. The atomization rate of AgNPs was faster than that of the dissolved silver ion. With increased amount of silver, the decay time observed from the time-dependent absorption peak profile was shortened in the case of dissolved silver ion, but it was increased in the case of AgNPs. With the particle size ranging from 10 to 100 nm, the detection sensitivity was indirectly proportional to the particle size, suggesting that TS-FF-AAS may offer insights into the particle size of AgNPs provided that the concentration of the silver is known. To obtain quantitative information on AgNPs, acid dissolution of the particles was performed before TS-FF-AAS analysis, and recoveries of 80-110% were obtained.

  15. Compression Behavior and Energy Absorption of Aluminum Alloy AA6061 Tubes with Multiple Holes

    NASA Astrophysics Data System (ADS)

    Simhachalam, Bade; Lakshmana Rao, C.; Srinivas, Krishna

    2014-05-01

    In this article, compression behavior and energy absorption of aluminum alloy AA6061 tubes are investigated both experimentally and numerically. Static and dynamic simulations are done using LS-Dyna Software for AA6061 tubes. True stress-plastic strain curves from the tensile test are used in the static and dynamic simulations of AA6061 tubes. The energy absorption values between experimental compression results and numeral simulation are found to be in good agreement. Dynamic simulations are done with drop velocity of up to 10 m/s to understand the inertia effects on energy absorption. The deformed modes from the numerical simulation are compared between tubes with and without holes in static and dynamic conditions.

  16. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

    PubMed

    Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-08-15

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  17. Absorption Mode FT-ICR Mass Spectrometry Imaging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode formore » Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.« less

  18. Atomic Absorption, Atomic Fluorescence, and Flame Emission Spectrometry.

    ERIC Educational Resources Information Center

    Horlick, Gary

    1984-01-01

    This review is presented in six sections. Sections focus on literature related to: (1) developments in instrumentation, measurement techniques, and procedures; (2) performance studies of flames and electrothermal atomizers; (3) applications of atomic absorption spectrometry; (4) analytical comparisons; (5) atomic fluorescence spectrometry; and (6)…

  19. Direct sampling graphite furnace atomic absorption spectrometry - feasibility of Na and K determination in desalted crude oil

    NASA Astrophysics Data System (ADS)

    Seeger, Tassia S.; Machado, Eduarda Q.; Flores, Erico M. M.; Mello, Paola A.; Duarte, Fabio A.

    2018-03-01

    In this study, Na and K were determined in desalted crude oil by direct sampling graphite furnace atomic absorption spectrometry (DS-GF AAS), with the use of a Zeeman-effect background correction system with variable magnetic field. The analysis was performed in low and high sensitivity conditions. Sodium determination was performed in two low-sensitivity conditions: 1) main absorption line (589.0 nm), gas stop flow during the atomization step and 3-field dynamic mode (0.6-0.8 T); and 2) secondary absorption line (330.3 nm), gas stop flow during the atomization and 2-field mode (0.8 T). In K determination, some parameters, such as high-sensitivity mode, main absorption line (766.5 nm), gas stop flow during the atomization and 2-field mode (0.8 T), were used. Suitability of chemical modifiers, such as Pd and W-Ir was also evaluated. The heating program for Na and K was based on the pyrolysis and atomization curves. Calibration was performed by aqueous standards. Accuracy was evaluated by the analysis of Green Petroleum Coke (SRM NIST 2718) and Trace Elements in Fuel Oil (SRM NIST 1634c). Recovery tests were also performed and results were compared with those obtained by GF AAS after crude oil digestion by microwave-assisted digestion. The characteristic mass of Na was 17.1 pg and 0.46 ng in conditions 1 and 2, respectively, while the one of K was 1.4 pg. Limits of detection and quantification by DS-GF AAS were 30 and 40 ng g-1 for Na and 3.2 and 4.2 ng g-1 for K, respectively. Sodium and K were determined in three crude oil samples with API density ranging from 20.9 to 28.0. Sodium and K concentration ranged from 1.5 to 73 μg g-1 and from 23 to 522 ng g-1, respectively.

  20. Detection of silver nanoparticles in parsley by solid sampling high-resolution-continuum source atomic absorption spectrometry.

    PubMed

    Feichtmeier, Nadine S; Leopold, Kerstin

    2014-06-01

    In this work, we present a fast and simple approach for detection of silver nanoparticles (AgNPs) in biological material (parsley) by solid sampling high-resolution-continuum source atomic absorption spectrometry (HR-CS AAS). A novel evaluation strategy was developed in order to distinguish AgNPs from ionic silver and for sizing of AgNPs. For this purpose, atomisation delay was introduced as significant indication of AgNPs, whereas atomisation rates allow distinction of 20-, 60-, and 80-nm AgNPs. Atomisation delays were found to be higher for samples containing silver ions than for samples containing silver nanoparticles. A maximum difference in atomisation delay normalised by the sample weight of 6.27 ± 0.96 s mg(-1) was obtained after optimisation of the furnace program of the AAS. For this purpose, a multivariate experimental design was used varying atomisation temperature, atomisation heating rate and pyrolysis temperature. Atomisation rates were calculated as the slope of the first inflection point of the absorbance signals and correlated with the size of the AgNPs in the biological sample. Hence, solid sampling HR-CS AAS was proved to be a promising tool for identifying and distinguishing silver nanoparticles from ionic silver directly in solid biological samples.

  1. Temperature-controlled electrothermal atomization-atomic absorption spectrometry using a pyrometric feedback system in conjunction with a background monitoring device

    NASA Astrophysics Data System (ADS)

    Van Deijck, W.; Roelofsen, A. M.; Pieters, H. J.; Herber, R. F. M.

    The construction of a temperature-controlled feedback system for electrothermal atomization-atomic absorption spectrometry (ETA-AAS) using an optical pyrometer applied to the atomization stage is described. The system was used in conjunction with a fast-response background monitoring device. The heating rate of the furnace amounted to 1400° s -1 with a reproducibility better than 1%. The precision of the temperature control at a steady state temperature of 2000°C was 0.1%. The analytical improvements offered by the present system have been demonstrated by the determination of cadmium and lead in blood and finally by the determination of lead in serum. Both the sensitivity and the precision of the method have been improved. The accuracy of the method was checked by determining the lead content for a number of scrum samples both by ETA-AAS and differential pulse anodic stripping voltametry (DPASV) and proved to be satisfactory.

  2. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-07-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R2 > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis.

  3. [Recent Development of Atomic Spectrometry in China].

    PubMed

    Xiao, Yuan-fang; Wang, Xiao-hua; Hang, Wei

    2015-09-01

    As an important part of modern analytical techniques, atomic spectrometry occupies a decisive status in the whole analytical field. The development of atomic spectrometry also reflects the continuous reform and innovation of analytical techniques. In the past fifteen years, atomic spectrometry has experienced rapid development and been applied widely in many fields in China. This review has witnessed its development and remarkable achievements. It contains several directions of atomic spectrometry, including atomic emission spectrometry (AES), atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), X-ray fluorescence spectrometry (XRF), and atomic mass spectrometry (AMS). Emphasis is put on the innovation of the detection methods and their applications in related fields, including environmental samples, biological samples, food and beverage, and geological materials, etc. There is also a brief introduction to the hyphenated techniques utilized in atomic spectrometry. Finally, the prospects of atomic spectrometry in China have been forecasted.

  4. Simultaneous Atomic Absorption Spectrometry for Cadmium and Lead Determination in Wastewater: A Laboratory Exercise

    ERIC Educational Resources Information Center

    Correia, Paulo R. M.; Oliveira, Pedro V.

    2004-01-01

    The simultaneous determination of cadmium and lead by multi-element atomic absorption spectrometry with electrochemical atomization is proposed by employing a problem-based approach. The reports indicate that the students assimilated the principles of the simultaneous atomic absorption spectrometry (SIMAAS), the role of the chemical modifier, the…

  5. CO AND H{sub 2} ABSORPTION IN THE AA TAURI CIRCUMSTELLAR DISK

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    France, Kevin; Burgh, Eric B.; Schindhelm, Eric

    2012-01-01

    The direct study of molecular gas in inner protoplanetary disks is complicated by uncertainties in the spatial distribution of the gas, the time variability of the source, and the comparison of observations across a wide range of wavelengths. Some of these challenges can be mitigated with far-ultraviolet spectroscopy. Using new observations obtained with the Hubble Space Telescope Cosmic Origins Spectrograph, we measure column densities and rovibrational temperatures for CO and H{sub 2} observed on the line of sight through the AA Tauri circumstellar disk. CO A - X absorption bands are observed against the far-UV continuum. The CO absorption ismore » characterized by log{sub 10}(N({sup 12}CO)) = 17.5 {+-} 0.5 cm{sup -2} and T{sub rot}(CO) = 500{sup +500}{sub -200} K, although this rotational temperature may underestimate the local kinetic temperature of the CO-bearing gas. We also detect {sup 13}CO in absorption with an isotopic ratio of {approx}20. We do not observe H{sub 2} absorption against the continuum; however, hot H{sub 2} (v > 0) is detected in absorption against the Ly{alpha} emission line. We measure the column densities in eight individual rovibrational states, determining a total log{sub 10}(N(H{sub 2})) = 17.9{sup +0.6}{sub -0.3} cm{sup -2} with a thermal temperature of T(H{sub 2}) = 2500{sup +800}{sub -700} K. The high temperature of the molecules, the relatively small H{sub 2} column density, and the high inclination of the AA Tauri disk suggest that the absorbing gas resides in an inner disk atmosphere. If the H{sub 2} and CO are cospatial within a molecular layer {approx}0.6 AU thick, this region is characterized by {approx} 10{sup 5} cm{sup -3} with an observed (CO/H{sub 2}) ratio of {approx}0.4. We also find evidence for a departure from a purely thermal H{sub 2} distribution, suggesting that excitation by continuum photons and H{sub 2} formation may be altering the level populations in the molecular gas.« less

  6. Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil.

    PubMed

    Frentiu, Tiberiu; Ponta, Michaela; Hategan, Raluca

    2013-03-01

    The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94-106% in atomic absorption and 97-103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6-5.2% in atomic absorption, similar with that of 1.9-6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric

  7. Bismuth as a general internal standard for lead in atomic absorption spectrometry.

    PubMed

    Bechlin, Marcos A; Fortunato, Felipe M; Ferreira, Edilene C; Gomes Neto, José A; Nóbrega, Joaquim A; Donati, George L; Jones, Bradley T

    2014-06-11

    Bismuth was evaluated as internal standard for Pb determination by line source flame atomic absorption spectrometry (LS FAAS), high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) and line source graphite furnace atomic absorption spectrometry (LS GFAAS). Analysis of samples containing different matrices indicated close relationship between Pb and Bi absorbances. Correlation coefficients of calibration curves built up by plotting A(Pb)/A(Bi)versus Pb concentration were higher than 0.9953 (FAAS) and higher than 0.9993 (GFAAS). Recoveries of Pb improved from 52-118% (without IS) to 97-109% (IS, LS FAAS); 74-231% (without IS) to 96-109% (IS, HR-CS FAAS); and 36-125% (without IS) to 96-110% (IS, LS GFAAS). The relative standard deviations (n=12) were reduced from 0.6-9.2% (without IS) to 0.3-4.3% (IS, LS FAAS); 0.7-7.7% (without IS) to 0.1-4.0% (IS, HR-CS FAAS); and 2.1-13% (without IS) to 0.4-5.9% (IS, LS GFAAS). Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of arsenic and selenium in water and sediment by graphite furnace atomic absorption spectrometry

    USGS Publications Warehouse

    Jones, Sandra R.; Garbarino, John R.

    1999-01-01

    Graphite furnace-atomic absorption spectrometry (GF-AAS) is a sensitive, precise, and accurate technique that can be used to determine arsenic and selenium in samples of water and sediment. The GF-AAS method has been developed to replace the hydride generation-atomic absorption spectrometry (HG-AAS) methods because the method detection limits are similar, bias and variability are comparable, and interferences are minimal. Advantages of the GF-AAS method include shorter sample preparation time, increased sample throughput from simultaneous multielement analysis, reduced amount of chemical waste, reduced sample volume requirements, increased linear concentration range, and the use of a more accurate digestion procedure. The linear concentration range for arsenic and selenium is 1 to 50 micrograms per liter in solution; the current method detection limit for arsenic in solution is 0.9 microgram per liter; the method detection limit for selenium in solution is 1 microgram per liter. This report describes results that were obtained using stop-flow and low-flow conditions during atomization. The bias and variability of the simultaneous determination of arsenic and selenium by GF-AAS under both conditions are supported with results from standard reference materials--water and sediment, real water samples, and spike recovery measurements. Arsenic and selenium results for all Standard Reference Water Samples analyzed were within one standard deviation of the most probable values. Long-term spike recoveries at 6.25, 25.0, 37.5 micrograms per liter in reagent-, ground-, and surface-water samples for arsenic averaged 103 plus or minus 2 percent using low-flow conditions and 104 plus or minus 4 percent using stop-flow conditions. Corresponding recoveries for selenium were 98 plus or minus 13 percent using low-flow conditions and 87 plus or minus 24 percent using stop-flow conditions. Spike recoveries at 25 micrograms per liter in 120 water samples ranged from 97 to 99 percent

  9. Noise-immune cavity-enhanced analytical atomic spectrometry - NICE-AAS - A technique for detection of elements down to zeptogram amounts

    NASA Astrophysics Data System (ADS)

    Axner, Ove; Ehlers, Patrick; Hausmaninger, Thomas; Silander, Isak; Ma, Weiguang

    2014-10-01

    Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) is a powerful technique for detection of molecular compounds in gas phase that is based on a combination of two important concepts: frequency modulation spectroscopy (FMS) for reduction of noise, and cavity enhancement, for prolongation of the interaction length between the light and the sample. Due to its unique properties, it has demonstrated unparalleled detection sensitivity when it comes to detection of molecular constituents in the gas phase. However, despite these, it has so far not been used for detection of atoms, i.e. for elemental analysis. The present work presents an assessment of the expected performance of Doppler-broadened (Db) NICE-OHMS for analytical atomic spectrometry, then referred to as noise-immune cavity-enhanced analytical atomic spectrometry (NICE-AAS). After a description of the basic principles of Db-NICE-OHMS, the modulation and detection conditions for optimum performance are identified. Based on a previous demonstrated detection sensitivity of Db-NICE-OHMS of 5 × 10- 12 cm- 1 Hz- 1/2 (corresponding to a single-pass absorbance of 7 × 10- 11 over 10 s), the expected limits of detection (LODs) of Hg and Na by NICE-AAS are estimated. Hg is assumed to be detected in gas phase directly while Na is considered to be atomized in a graphite furnace (GF) prior to detection. It is shown that in the absence of spectral interferences, contaminated sample compartments, and optical saturation, it should be feasible to detect Hg down to 10 zg/cm3 (10 fg/m3 or 10- 5 ng/m3), which corresponds to 25 atoms/cm3, and Na down to 0.5 zg (zg = zeptogram = 10- 21 g), representing 50 zg/mL (parts-per-sextillion, pps, 1:1021) in liquid solution (assuming a sample of 10 μL) or solely 15 atoms injected into the GF, respectively. These LODs are several orders of magnitude lower (better) than any previous laser-based absorption technique previously demonstrated under atmospheric

  10. Determination of Cd in urine by cloud point extraction-tungsten coil atomic absorption spectrometry.

    PubMed

    Donati, George L; Pharr, Kathryn E; Calloway, Clifton P; Nóbrega, Joaquim A; Jones, Bradley T

    2008-09-15

    Cadmium concentrations in human urine are typically at or below the 1 microgL(-1) level, so only a handful of techniques may be appropriate for this application. These include sophisticated methods such as graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry. While tungsten coil atomic absorption spectrometry is a simpler and less expensive technique, its practical detection limits often prohibit the detection of Cd in normal urine samples. In addition, the nature of the urine matrix often necessitates accurate background correction techniques, which would add expense and complexity to the tungsten coil instrument. This manuscript describes a cloud point extraction method that reduces matrix interference while preconcentrating Cd by a factor of 15. Ammonium pyrrolidinedithiocarbamate and Triton X-114 are used as complexing agent and surfactant, respectively, in the extraction procedure. Triton X-114 forms an extractant coacervate surfactant-rich phase that is denser than water, so the aqueous supernatant is easily removed leaving the metal-containing surfactant layer intact. A 25 microL aliquot of this preconcentrated sample is placed directly onto the tungsten coil for analysis. The cloud point extraction procedure allows for simple background correction based either on the measurement of absorption at a nearby wavelength, or measurement of absorption at a time in the atomization step immediately prior to the onset of the Cd signal. Seven human urine samples are analyzed by this technique and the results are compared to those found by the inductively coupled plasma mass spectrometry analysis of the same samples performed at a different institution. The limit of detection for Cd in urine is 5 ngL(-1) for cloud point extraction tungsten coil atomic absorption spectrometry. The accuracy of the method is determined with a standard reference material (toxic metals in freeze-dried urine) and the determined values agree with

  11. Micro-sampling method based on high-resolution continuum source graphite furnace atomic absorption spectrometry for calcium determination in blood and mitochondrial suspensions.

    PubMed

    Gómez-Nieto, Beatriz; Gismera, Mª Jesús; Sevilla, Mª Teresa; Satrústegui, Jorgina; Procopio, Jesús R

    2017-08-01

    A micro-sampling and straightforward method based on high resolution continuum source atomic absorption spectrometry (HR-CS AAS) was developed to determine extracellular and intracellular Ca in samples of interest in clinical and biomedical analysis. Solid sampling platforms were used to introduce the micro-samples into the graphite furnace atomizer. The secondary absorption line for Ca, located at 239.856nm, was selected to carry out the measurements. Experimental parameters such as pyrolysis and atomization temperatures and the amount of sample introduced for the measurements were optimized. Calibration was performed using aqueous standards and the approach to measure at the wings of the absorption lines was employed for the expansion of the linear response range. The limit of detection was of 0.02mgL -1 Ca (0.39ng Ca) and the upper limit of linear range was increased up to 8.0mgL -1 Ca (160ng Ca). The proposed method was used to determine Ca in mitochondrial suspensions and whole blood samples with successful results. Adequate recoveries (within 91-107%) were obtained in the tests performed for validation purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil

    PubMed Central

    2013-01-01

    Background The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. Results The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94–106% in atomic absorption and 97–103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6–5.2% in atomic absorption, similar with that of 1.9–6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference

  13. [Application of atomic absorption spectrometry in the engine knock detection].

    PubMed

    Chen, Li-Dan

    2013-02-01

    Because existing human experience diagnosis method and apparatus for auxiliary diagnosis method are difficult to diagnose quickly engine knock. Atomic absorption spectrometry was used to detect the automobile engine knock in in innovative way. After having determined Fe, Al, Cu, Cr and Pb content in the 35 groups of Audi A6 engine oil whose travel course is 2 000 -70 000 kilometers and whose sampling interval is 2 000 kilometers by atomic absorption spectrometry, the database of primary metal content in the same automobile engine at different mileage was established. The research shows that the main metal content fluctuates within a certain range. In practical engineering applications, after the determination of engine oil main metal content and comparison with its database value, it can not only help to diagnose the type and location of engine knock without the disintegration and reduce vehicle maintenance costs and improve the accuracy of engine knock fault diagnosis.

  14. Determination of silicon in biomass and products of pyrolysis process via high-resolution continuum source atomic absorption spectrometry.

    PubMed

    Nakadi, Flávio V; Prodanov, Caroline; Boschetti, Wiliam; Vale, Maria Goreti R; Welz, Bernhard; de Andrade, Jailson B

    2018-03-01

    Thermochemical processes can convert the biomass into fuels, such as bio-oil. The biomass submitted to pyrolysis process, such as fibers, are generally rich in silicon, an element that can lead to damages in an engine when there is high concentration in a fuel. High-resolution continuum source atomic absorption spectrometry (HR-CS AAS) is an interesting alternative for Si determination in the products and byproducts of the pyrolysis process because, besides the flame (F) and graphite furnace (GF) atomizers, it has enhanced the application of direct analysis of solid samples (SS) within GF. This study aimed the development of methods to determine Si in biomass samples, their products and byproducts using HR-CS AAS. A high-resolution continuum source atomic absorption spectrometer contrAA 700 equipped with F and GF atomizers was used throughout the study. HR-CS F AAS (λ = 251.611nm, 1 detection pixel, N 2 O/C 2 H 2 flame) was used to evaluate Si content in biomass and ash, after a microwave-assisted acid digestion with HNO 3 and HF. HR-CS GF AAS (T pyr = 1400°C, T atom = 2650°C) has evaluated Si in pyrolysis water and bio-oil at 251.611nm, and in peach pit biomass and ash at 221.174nm using SS, both wavelengths with 1 detection pixel. Rhodium (300μg) was applied as permanent modifier and 10μgPd + 6μg Mg were pipetted onto the standards/samples at each analysis. Three different biomass samples were studied: palm tree fiber, coconut fiber and peach pit, and three certified reference materials (CRM) were used to verify the accuracy of the methods. The figures of merit were LOD 0.09-20mgkg -1 , and LOQ 0.3-20mgkg -1 , considering all the methods. There were no significant differences between the CRM certified values and the determined ones, using a Student t-test with a confidence interval of 95% (n = 5). Si concentration ranged from 0.11-0.92% mm -1 , 1.1-1.7mgkg -1 , 3.3-13mgkg -1 , and 0.41-1.4%mm -1 , in biomass, bio-oil, pyrolysis water and ash, respectively

  15. Feasibility of high-resolution continuum source molecular absorption spectrometry in flame and furnace for sulphur determination in petroleum products

    NASA Astrophysics Data System (ADS)

    Kowalewska, Zofia

    2011-07-01

    For the first time, high-resolution molecular absorption spectrometry with a high-intensity xenon lamp as radiation source has been applied for the determination of sulphur in crude oil and petroleum products. The samples were analysed as xylene solutions using vaporisation in acetylene-air flame or in an electrothermally heated graphite furnace. The sensitive rotational lines of the CS molecule, belonging to the ∆ν = 0 vibrational sequence within the electronic transition X 1∑ + → A 1П, were applied. For graphite furnace molecular absorption spectrometry, the Pd + Mg organic modifier was selected. Strong interactions with Pd atoms enable easier decomposition of sulphur-containing compounds, likely through the temporal formation of Pd xS y molecules. At the 258.056 nm line, with the wavelength range covering central pixel ± 5 pixels and with application of interactive background correction, the detection limit was 14 ng in graphite furnace molecular absorption spectrometry and 18 mg kg -1 in flame molecular absorption spectrometry. Meanwhile, application of 2-points background correction found a characteristic mass of 12 ng in graphite furnace molecular absorption spectrometry and a characteristic concentration of 104 mg kg -1 in flame molecular absorption spectrometry. The range of application of the proposed methods turned out to be significantly limited by the properties of the sulphur compounds of interest. In the case of volatile sulphur compounds, which can be present in light petroleum products, severe difficulties were encountered. On the contrary, heavy oils and residues from distillation as well as crude oil could be analysed using both flame and graphite furnace vaporisation. The good accuracy of the proposed methods for these samples was confirmed by their mutual consistency and the results from analysis of reference samples (certified reference materials and home reference materials with sulphur content determined by X-ray fluorescence

  16. Chemometric evaluation of Cd, Co, Cr, Cu, Ni (inductively coupled plasma optical emission spectrometry) and Pb (graphite furnace atomic absorption spectrometry) concentrations in lipstick samples intended to be used by adults and children.

    PubMed

    Batista, Érica Ferreira; Augusto, Amanda dos Santos; Pereira-Filho, Edenir Rodrigues

    2016-04-01

    A method was developed for determining the concentrations of Cd, Co, Cr, Cu, Ni and Pb in lipstick samples intended to be used by adults and children using inductively coupled plasma optical emission spectrometry (ICP OES) and graphite furnace atomic absorption spectrometry (GF AAS) after treatment with dilute HNO3 and hot block. The combination of fractional factorial design and Desirability function was used to evaluate the ICP OES operational parameters and the regression models using Central Composite and Doehlert designs were calculated to stablish the best working condition for all analytes. Seventeen lipstick samples manufactured in different countries with different colors and brands were analyzed. Some samples contained high concentrations of toxic elements, such as Cr and Pb, which are carcinogenic and cause allergic and eczematous dermatitis. The maximum concentration detected was higher than the permissible safe limits for human use, and the samples containing these high metal concentrations were intended for use by children. Principal component analysis (PCA) was used as a chemometrics tool for exploratory analysis to observe the similarities between samples relative to the metal concentrations (a correlation between Cd and Pb was observed). Copyright © 2015 Elsevier B.V. All rights reserved.

  17. In-situ pre-concentration through repeated sampling and pyrolysis for ultrasensitive determination of thallium in drinking water by electrothermal atomic absorption spectrometry.

    PubMed

    Liu, Liwei; Zheng, Huaili; Xu, Bincheng; Xiao, Lang; Chigan, Yong; Zhangluo, Yilan

    2018-03-01

    In this paper, a procedure for in-situ pre-concentration in graphite furnace by repeated sampling and pyrolysis is proposed for the determination of ultra-trace thallium in drinking water by graphite furnace atomic absorption spectrometry (GF-AAS). Without any other laborious enrichment processes that routinely result in analyte loss and contamination, thallium was directly concentrated in the graphite furnace automatically and subsequently subject to analysis. The effects of several key factors, such as the temperature for pyrolysis and atomization, the chemical modifier, and the repeated sampling times were investigated. Under the optimized conditions, a limit of detection of 0.01µgL -1 was obtained, which fulfilled thallium determination in drinking water by GB 5749-2006 regulated by China. Successful analysis of thallium in certified water samples and drinking water samples was demonstrated, with analytical results in good agreement with the certified values and those by inductively coupled plasma mass spectrometry (ICP-MS), respectively. Routine spike-recovery tests with randomly selected drinking water samples showed satisfactory results of 80-96%. The proposed method is simple and sensitive for screening of ultra-trace thallium in drinking water samples. Copyright © 2017. Published by Elsevier B.V.

  18. Speciation analysis of arsenic in biological matrices by automated hydride generation-cryotrapping-atomic absorption spectrometry with multiple microflame quartz tube atomizer (multiatomizer)

    PubMed Central

    Hernández-Zavala, Araceli; Matoušek, Tomáš; Drobná, Zuzana; Paul, David S.; Walton, Felecia; Adair, Blakely M.; Jiří, Dědina; Thomas, David J.

    2008-01-01

    Analyses of arsenic (As) species in tissues and body fluids of individuals chronically exposed to inorganic arsenic (iAs) provide essential information about the exposure level and pattern of iAs metabolism. We have previously described an oxidation state-specific analysis of As species in biological matrices by hydride-generation atomic absorption spectrometry (HG-AAS), using cryotrapping (CT) for preconcentration and separation of arsines. To improve performance and detection limits of the method, HG and CT steps are automated and a conventional flame-in-tube atomizer replaced with a recently developed multiple microflame quartz tube atomizer (multiatomizer). In this system, arsines from AsIII-species are generated in a mixture of Tris-HCl (pH 6) and sodium borohydride. For generation of arsines from both AsIII- and AsV-species, samples are pretreated with L-cysteine. Under these conditions, dimethylthioarsinic acid, a newly described metabolite of iAs, does not interfere significantly with detection and quantification of methylated trivalent arsenicals. Analytical performance of the automated HG-CT-AAS was characterized by analyses of cultured cells and mouse tissues that contained mono- and dimethylated metabolites of iAs. The capacity to detect methylated AsIII- and AsV-species was verified, using an in vitro methylation system containing recombinant rat arsenic (+3 oxidation state) methyltransferase and cultured rat hepatocytes treated with iAs. Compared with the previous HG-CT-AAS design, detection limits for iAs and its metabolites have improved significantly with the current system, ranging from 8 to 20 pg. Recoveries of As were between 78 and 117%. The precision of the method was better than 5% for all biological matrices examined. Thus, the automated HG-CT-AAS system provides an effective and sensitive tool for analysis of all major human metabolites of iAs in complex biological matrices. PMID:18677417

  19. Determination of calcium, magnesium and zinc in lubricating oils by flame atomic absorption spectrometry using a three-component solution.

    PubMed

    Zmozinski, Ariane V; de Jesus, Alexandre; Vale, Maria G R; Silva, Márcia M

    2010-12-15

    Lubricating oils are used to decrease wear and friction of movable parts of engines and turbines, being in that way essential for the performance and the increase of that equipment lifespan. The presence of some metals shows the addition of specific additives such as detergents, dispersals and antioxidants that improve the performance of these lubricants. In this work, a method for determination of calcium, magnesium and zinc in lubricating oil by flame atomic absorption spectrometry (F AAS) was developed. The samples were diluted with a small quantity of aviation kerosene (AVK), n-propanol and water to form a three-component solution before its introduction in the F AAS. Aqueous inorganic standards diluted in the same way have been used for calibration. To assess the accuracy of the new method, it was compared with ABNT NBR 14066 standard method, which consists in diluting the sample with AVK and in quantification by F AAS. Two other validating methods have also been used: the acid digestion and the certified reference material NIST (SRM 1084a). The proposed method provides the following advantages in relation to the standard method: significant reduction of the use of AVK, higher stability of the analytes in the medium and application of aqueous inorganic standards for calibration. The limits of detection for calcium, magnesium and zinc were 1.3 μg g(-1), 0.052 μg g(-1) and 0.41 μg g(-1), respectively. Concentrations of calcium, magnesium and zinc in six different samples obtained by the developed method did not differ significantly from the results obtained by the reference methods at the 95% confidence level (Student's t-test and ANOVA). Therefore, the proposed method becomes an efficient alternative for determination of metals in lubricating oil. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Investigation of chemical modifiers for the direct determination of arsenic in fish oil using high-resolution continuum source graphite furnace atomic absorption spectrometry.

    PubMed

    Pereira, Éderson R; de Almeida, Tarcísio S; Borges, Daniel L G; Carasek, Eduardo; Welz, Bernhard; Feldmann, Jörg; Campo Menoyo, Javier Del

    2016-04-01

    High-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) has been applied for the development of a method for the determination of total As in fish oil samples using direct analysis. The method does not use any sample pretreatment, besides dilution with 1-propanole, in order to decrease the oil viscosity. The stability and sensitivity of As were evaluated using ruthenium and iridium as permanent chemical modifiers and palladium added in solution over the sample. The best results were obtained with ruthenium as the permanent modifier and palladium in solution added to samples and standard solutions. Under these conditions, aqueous standard solutions could be used for calibration for the fish oil samples diluted with 1-propanole. The pyrolysis and atomization temperatures were 1400 °C and 2300 °C, respectively, and the limit of detection and characteristic mass were 30 pg and 43 pg, respectively. Accuracy and precision of the method have been evaluated using microwave-assisted acid digestion of the samples with subsequent determination by HR-CS GF AAS and ICP-MS; the results were in agreement (95% confidence level) with those of the proposed method. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Detection of AA-type amyloid protein in labial salivary glands.

    PubMed

    Sacsaquispe, Sonia-Julia; Antúnez-de Mayolo, Eleazar-Antonio; Vicetti, Rodolfo; Delgado, Wilson-Alejandro

    2011-03-01

    Among the diverse forms of amyloidosis, secondary type is the most frequent one. Diagnosis of amyloid deposition is based on the identification of the fibrillary protein amyloid by means of Congo Red (CR) or crystal violet (CV) stains, but these techniques do not differentiate between the different types of amyloid fibrils. The aim of this study was to identify by immunofluorescence (IF) AA amyloid a pathological fibrillar low-molecular-weight protein formed by cleavage of serum amyloid A (SAA) protein in labial salivary gland (LSG) biopsies from patients with secondary amyloidosis. 98 LSG were studied, 65 were from patients with secondary amyloidosis and 33 from subjects with chronic inflammatory diseases without evidence of this anomaly. All sections were stained with hematoxylin and eosin (H &E), CV, CR and IF using anti-AA antibodies. Positive and negative controls were used for all techniques. CV and CR demonstrated that the amyloid substance was found mainly distributed periductally (93.8%), followed by periacinar and perivascular locations (p <0.001); however, the IF demonstrated that amyloid AA substance predominates in the periacinar area (73.8%), followed by periductal and perivascular locations (p <0.001). IF has a sensitivity of 83%, 100% of specificity, 100% of predictive positive value and 75% of predictive negative value. The results of this study confirm the efficacy of the LSG biopsy as a highly reliable method for diagnosis of secondary amyloidosis.

  2. Vaporization and atomization of uranium in a graphite tube electrothermal vaporizer: a mechanistic study using electrothermal vaporization inductively coupled plasma mass spectrometry and graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Goltz, D. M.; Grégoire, D. C.; Byrne, J. P.; Chakrabarti, C. L.

    1995-07-01

    The mechanism of vaporization and atomization of U in a graphite tube electrothermal vaporizer was studied using graphite furnace atomic absorption spectrometry (GFAAS) and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Graphite furnace AAS studies indicate U atoms are formed at temperatures above 2400°C. Using ETV-ICP-MS, an appearance temperature of 1100°C was obtained indicating that some U vaporizes as U oxide. Although U carbides form at temperatures above 2000°C, ETV-ICP-MS studies show that they do not vaporize until 2600°C. In the temperature range between 2200°C and 2600°C, U atoms in GFAAS are likely formed by thermal dissociation of U oxide, whereas at higher temperatures, U atoms are formed via thermal dissociation of U carbide. The origin of U signal suppression in ETV-ICP-MS by NaCl was also investigated. At temperatures above 2000°C, signal suppression may be caused by the accelerated rate of formation of carbide species while at temperatures below 2000°C, the presence of NaCl may cause intercalation of the U in the graphite layers resulting in partial retention of U during the vaporization step. The use of 0.3% freon-23 (CHF 3) mixed with the argon carrier gas was effective in preventing the intercalation of U in graphite and U carbide formation at 2700°C.

  3. [Development of ICP-OES, ICP-MS and GF-AAS Methods for Simultaneous Quantification of Lead, Total Arsenic and Cadmium in Soft Drinks].

    PubMed

    Kataoka, Yohei; Watanabe, Takahiro; Hayashi, Tomoko; Teshima, Reiko; Matsuda, Rieko

    2015-01-01

    In this study, we developed methods to quantify lead, total arsenic and cadmium contained in various kinds of soft drinks, and we evaluated their performance. The samples were digested by common methods to prepare solutions for measurement by ICP-OES, ICP-MS and graphite furnace atomic absorption spectrometry (GF-AAS). After digestion, internal standard was added to the digestion solutions for measurements by ICP-OES and ICP-MS. For measurement by GF-AAS, additional purification of the digestion solution was conducted by back-extraction of the three metals into nitric acid solution after extraction into an organic solvent with ammonium pyrrolidine dithiocarbamate. Performance of the developed methods were evaluated for eight kinds of soft drinks.

  4. Diode laser differential absorption spectrometry for measurements of some parameters of condensed media.

    PubMed

    Liger, V V; Bolshov, M A; Kuritsyn, Yu A; Krivtsun, V M; Zybin, A V; Niemax, K

    2007-04-01

    A method of diode laser differential absorption spectrometry (DLDAS) is proposed. The method is based on the detection of absorption spectra variations caused by the changes of a parameter of a condensed media (temperature, composition of the components of a mixture, pH, etc.). Some simple theoretical background of the proposed technique is presented. The potentialities of the method are demonstrated in the experiments on remote contactless measurement of the temperature of aqueous solutions and measurement of the deviations of the composition of a mixture of dyes from the equilibrium state.

  5. Accelerator mass spectrometry analysis of aroma compound absorption in plastic packaging materials

    NASA Astrophysics Data System (ADS)

    Stenström, Kristina; Erlandsson, Bengt; Hellborg, Ragnar; Wiebert, Anders; Skog, Göran; Nielsen, Tim

    1994-05-01

    Absorption of aroma compounds in plastic packaging materials may affect the taste of the packaged food and it may also change the quality of the packaging material. A method to determine the aroma compound absorption in polymers by accelerator mass spectrometry (AMS) is being developed at the Lund Pelletron AMS facility. The high sensitivity of the AMS method makes it possible to study these phenomena under realistic conditions. As a first test low density polyethylene exposed to 14C-doped ethyl acetate is examined. After converting the polymer samples with the absorbed aroma compounds to graphite, the {14C }/{13C } ratio of the samples is measured by the AMS system and the degree of aroma compound absorption is established. The results are compared with those obtained by supercritical fluid extraction coupled to gas chromatography (SFE-GC).

  6. Species selective preconcentration and quantification of gold nanoparticles using cloud point extraction and electrothermal atomic absorption spectrometry.

    PubMed

    Hartmann, Georg; Schuster, Michael

    2013-01-25

    The determination of metallic nanoparticles in environmental samples requires sample pretreatment that ideally combines pre-concentration and species selectivity. With cloud point extraction (CPE) using the surfactant Triton X-114 we present a simple and cost effective separation technique that meets both criteria. Effective separation of ionic gold species and Au nanoparticles (Au-NPs) is achieved by using sodium thiosulphate as a complexing agent. The extraction efficiency for Au-NP ranged from 1.01 ± 0.06 (particle size 2 nm) to 0.52 ± 0.16 (particle size 150 nm). An enrichment factor of 80 and a low limit of detection of 5 ng L(-1) is achieved using electrothermal atomic absorption spectrometry (ET-AAS) for quantification. TEM measurements showed that the particle size is not affected by the CPE process. Natural organic matter (NOM) is tolerated up to a concentration of 10 mg L(-1). The precision of the method expressed as the standard deviation of 12 replicates at an Au-NP concentration of 100 ng L(-1) is 9.5%. A relation between particle concentration and the extraction efficiency was not observed. Spiking experiments showed a recovery higher than 91% for environmental water samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Polonium (²¹⁰Po), uranium (²³⁴U, ²³⁸U) isotopes and trace metals in mosses from Sobieszewo Island, northern Poland.

    PubMed

    Boryło, Alicja; Nowicki, Waldemar; Olszewski, Grzegorz; Skwarzec, Bogdan

    2012-01-01

    The activity of polonium (210)Po and uranium (234)U, (238)U radionuclides, as well as trace metals in mosses, collected from Sobieszewo Island area (northern Poland), were determined using the alpha spectrometry, AAS (atomic absorption spectrometry) and OES-ICP (atomic emission spectrometry with inductively coupled plasma). The concentrations of mercury (directly from the solid sample) were determined by the cold vapor technique of CV AAS. The obtained results revealed that the concentrations of (210)Po, (234)U, and (238)U in the two analyzed kinds of mosses: schrebers big red stem moss (Pleurozium schreberi) and broom moss (Dicranum scoparium) were similar. The higher polonium concentrations were found in broom moss (Dicranum scoparium), but uranium concentrations were relatively low for both species of analyzed mosses. Among the analyzed trace metals the highest concentration in mosses was recorded for iron, while the lowest for nickel, cadmium and mercury. The obtained studies showed that the sources of polonium and uranium isotopes, as well as trace metals in analyzed mosses are air city contaminations transported from Gdańsk and from existing in the vicinity the phosphogypsum waste heap in Wiślinka (near Gdańsk).

  8. Coupled high performance liquid chromatography-microwave digestion-hydride generation-atomic absorption spectrometry for inorganic and organic arsenic speciation in fish tissue.

    PubMed

    Villa-Lojo, M C; Alonso-Rodríguez, E; López-Mahía, P; Muniategui-Lorenzo, S; Prada-Rodríguez, D

    2002-06-10

    A high performance liquid chromatography-microwave digestion-hydride generation-atomic absorption spectrometry (HPLC-MW-HG-AAS) coupled method is described for As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB) and arsenocholine (AsC) determination. A Hamilton PRP-X100 anion-exchange column is used for carrying out the arsenic species separation. As mobile phase 17 mM phosphate buffer (pH 6.0) is used for As(III), As(V), MMA and DMA separation, and ultrapure water (pH 6.0) for AsB and AsC separation. Prior to injection into the HPLC system AsB and AsC are isolated from the other arsenic species using a Waters Accell Plus QMA cartridge. A microwave digestion with K(2)S(2)O(8) as oxidizing agent is used for enhancing the efficiency of conversion of AsB and AsC into arsenate. Detection limits achieved were between 0.3 and 1.1 ng for all species. The method was applied to arsenic speciation in fish samples.

  9. Determination of cadmium in coal using solid sampling graphite furnace high-resolution continuum source atomic absorption spectrometry.

    PubMed

    da Silva, Alessandra Furtado; Borges, Daniel L G; Lepri, Fábio Grandis; Welz, Bernhard; Curtius, Adilson J; Heitmann, Uwe

    2005-08-01

    This work describes the development of a method to determine cadmium in coal, in which iridium is used as a permanent chemical modifier and calibration is performed against aqueous standards by high-resolution continuum source atomic absorption spectrometry (HR-CS AAS). This new instrumental concept makes the whole spectral environment in the vicinity of the analytical line accessible, providing a lot more data than just the change in absorbance over time available from conventional instruments. The application of Ir (400 microg) as a permanent chemical modifier, thermally deposited on the pyrolytic graphite platform surface, allowed pyrolysis temperatures of 700 degrees C to be used, which was sufficiently high to significantly reduce the continuous background that occurred before the analyte signal at pyrolysis temperatures <700 degrees C. Structured background absorption also occurred after the analyte signal when atomization temperatures of >1600 degrees C were used, which arose from the electron-excitation spectrum (with rotational fine structure) of a diatomic molecule. Under optimized conditions (pyrolysis at 700 degrees C and atomization at 1500 degrees C), interference-free determination of cadmium in seven certified coal reference materials and two real samples was achieved by direct solid sampling and calibrating against aqueous standards, resulting in good agreement with the certified values (where available) at the 95% confidence level. A characteristic mass of 0.4 pg and a detection limit of 2 ng g(-1), calculated for a sample mass of 1.0 mg coal, was obtained. A precision (expressed as the relative standard deviation, RSD) of <10% was typically obtained when coal samples in the mass range 0.6-1.2 mg were analyzed.

  10. Determination of lead, cadmium and mercury in blood for assessment of environmental exposure: A comparison between inductively coupled plasma mass spectrometry and atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Palmer, Christopher D.; Lewis, Miles E.; Geraghty, Ciaran M.; Barbosa, Fernando; Parsons, Patrick J.

    2006-08-01

    A biomonitoring method for the determination of Pb, Cd, and Hg at background levels in whole blood by inductively coupled plasma-mass spectrometry is described. While this method was optimized for assessing Pb, Cd and Hg at environmental levels, it also proved suitable for assessing concentrations associated with occupational exposure. The method requires as little as 200 μl of blood that is diluted 1 + 49 for direct analysis in the inductively coupled plasma-mass spectrometer. Method performance is compared to well-established AAS methods. Initial method validation was accomplished using National Institute of Standards and Technology (NIST) Standard Reference Material 966, Toxic Metals in Bovine Blood. Method detection limits (3s) are 0.05 μg dl - 1 for Pb, 0.09 μg l - 1 for Cd; and 0.17 μg l - 1 for Hg. Repeatability ranged from 1.4% to 2.8% for Pb; 3% to 10% for Cd; and 2.6% to 8.8% for Hg. In contrast, AAS method detection limits were 1 μg dl - 1 , 0.54 μg l - 1 , and 0.6 μg l - 1 , for Pb, Cd, and Hg, respectively. Further performance assessments were conducted over a 2-year period via participation in four international External Quality Assessment Schemes (EQAS) operated specifically for toxic metals in blood. This includes schemes operated by (a) the New York State Department of Health's Wadsworth Center, Albany, NY, USA (b) L'Institut National de Santé Publique du Québec, Centre de Toxicologie du Québec, Canada, (c) Friedrich-Alexander University, Erlangen, Germany, and (d) the University of Surrey, Guildford, UK Trace Elements scheme. The EQAS data reflect analytical performance for blind samples analyzed independently by both inductively coupled plasma-mass spectrometry and AAS methods.

  11. Investigation of an alternating current plasma as an element selective atomic emission detector for high-resolution capillary gas chromatography and as a source for atomic absorption and atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Ombaba, Jackson M.

    This thesis deals with the construction and evaluation of an alternating current plasma (ACP) as an element-selective detector for high resolution capillary gas chromatography (GC) and as an excitation source for atomic absorption spectrometry (AAS) and atomic emission spectrometry (AES). The plasma, constrained in a quartz discharge tube at atmospheric pressure, is generated between two copper electrodes and utilizes helium as the plasma supporting gas. The alternating current plasma power source consists of a step-up transformer with a secondary output voltage of 14,000 V at a current of 23 mA. The device exhibits a stable signal because the plasma is self-seeding and reignites itself every half cycle. A tesla coil is not required to commence generation of the plasma if the ac voltage applied is greater than the breakdown voltage of the plasma-supporting gas. The chromatographic applications studied included the following: (1) the separation and selective detection of the organotin species, tributyltin chloride (TBT) and tetrabutyltin (TEBT), in environmental matrices including mussels (Mvutilus edullus) and sediment from Boston Harbor, industrial waste water and industrial sludge, and (2) the detection of methylcyclopentadienyl manganesetricarbonyl (MMT) and similar compounds used as gasoline additives. An ultrasonic nebulizer (common room humidifier) was utilized as a sample introduction device for aqueous solutions when the ACP was employed as an atomization source for atomic absorption spectrometry and as an excitation source for atomic emission spectrometry. Plasma diagnostic parameters studied include spatial electron number density across the discharge tube, electronic, excitation and ionization temperatures. Interference studies both in absorption and emission modes were also considered. Figures of merits of selected elements both in absorption and emission modes are reported. The evaluation of a computer-aided optimization program, Drylab GC, using

  12. Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food: Outcome of the collaborative trial IMEP-41.

    PubMed

    Fiamegkos, I; Cordeiro, F; Robouch, P; Vélez, D; Devesa, V; Raber, G; Sloth, J J; Rasmussen, R R; Llorente-Mirandes, T; Lopez-Sanchez, J F; Rubio, R; Cubadda, F; D'Amato, M; Feldmann, J; Raab, A; Emteborg, H; de la Calle, M B

    2016-12-15

    A collaborative trial was conducted to determine the performance characteristics of an analytical method for the quantification of inorganic arsenic (iAs) in food. The method is based on (i) solubilisation of the protein matrix with concentrated hydrochloric acid to denature proteins and allow the release of all arsenic species into solution, and (ii) subsequent extraction of the inorganic arsenic present in the acid medium using chloroform followed by back-extraction to acidic medium. The final detection and quantification is done by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). The seven test items used in this exercise were reference materials covering a broad range of matrices: mussels, cabbage, seaweed (hijiki), fish protein, rice, wheat, mushrooms, with concentrations ranging from 0.074 to 7.55mgkg(-1). The relative standard deviation for repeatability (RSDr) ranged from 4.1 to 10.3%, while the relative standard deviation for reproducibility (RSDR) ranged from 6.1 to 22.8%. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Analysis of Dithiocarbamate Fungicides in Vegetable Matrices Using HPLC-UV Followed by Atomic Absorption Spectrometry.

    PubMed

    Al-Alam, Josephine; Bom, Laura; Chbani, Asma; Fajloun, Ziad; Millet, Maurice

    2017-04-01

    A simple method combining ion-pair methylation, high-performance liquid chromatography (HPLC) analysis with detection at 272 nm and atomic absorption spectrometry was developed in order to determine 10 dithiocarbamate fungicides (Dazomet, Metam-sodium, Ferbam, Ziram, Zineb, Maneb, Mancozeb, Metiram, Nabam and Propineb) and distinguish ethylenbisdithiocarbamates (EBDTCs) Zineb, Maneb and Mancozeb in diverse matrices. This method associates reverse phase analysis by HPLC analysis with detection at 272 nm, with atomic absorption spectrometry in order to distinguish, with the same extraction protocol, Maneb, Mancozeb and Zineb. The limits of detection (0.4, 0.8, 0.5, 1.25 and 1.97) and quantification (1.18, 2.5, 1.52, 4.2 and 6.52) calculated in injected nanogram, respectively, for Dazomet, Metam-Na, dimethyldithiocarbamates (DMDTCs), EBDTCs and propylenebisdithiocarbamates (PBDTCs) justify the sensitivity of the method used. The coefficients of determination R2 were 0.9985, 0.9978, 0.9949, 0.988 and 0.9794, respectively, for Dazomet, Metam-Na, DMDTCs, EBDTCs and PBDTCs, and the recovery from fortified apple and leek samples was above 90%. Results obtained with the atomic absorption method in comparison with spectrophotometric analysis focus on the importance of the atomic absorption as a complementary specific method for the distinction between different EBDTCs fungicides. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Evaluation of inorganic elements in cat's claw teas using ICP OES and GF AAS.

    PubMed

    Pereira, João B; Dantas, Kelly G F

    2016-04-01

    The determination of Ba, Ca, Cu, Fe, Mg, Mn, P, Pb, and Zn by inductively coupled plasma optical emission spectrometry (ICP OES), and Se by graphite furnace atomic absorption spectrometry (GF AAS), has been carried out in dry matter and teas from 11 samples of the cat's claw plant. The accuracy and precision values were verified against GBW 07604 (Poplar leaves) certified reference material and by the recovery test. Results showed a high content of Ca in the medicinal plant studied, followed by Mg and P. The values obtained showed that the elements studied have different concentrations depending on the method of tea preparation. The highest levels were observed in Ca and Mg, and the lowest for Se and Pb, by both infusion and decoction. Teas prepared from this plant were found to be at safe levels for human consumption, and may be suitable as sources of these elements in the human diet. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Determination of tellurium by hydride generation with in situ trapping flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Matusiewicz, Henryk; Krawczyk, Magdalena

    2007-03-01

    The analytical performance of coupled hydride generation — integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Te in reference material (GBW 07302 Stream Sediment), coal fly ash and garlic. Tellurium, using formation of H 2Te vapors, is atomized in air-acetylene flame-heated IAT. A new design HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube or an "integrated trap") was investigated. An improvement in detection limit was achieved compared with using either of the above atom trapping techniques separately. The concentration detection limit, defined as 3 times the blank standard deviation (3 σ), was 0.9 ng mL - 1 for Te. For a 2 min in situ pre-concentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, was 222 fold, using the hydride generation — atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 7.0% ( n = 6) for Te. The designs studied include slotted tube, single silica tube and integrated atom trap-cooled atom traps. The accuracy of the method was verified using a certified reference material (GBW 07302 Stream Sediment) by aqueous standard calibration curves. The measured Te contents of the reference material was in agreement with the information value. The method was successfully applied to the determination of tellurium in coal fly ash and garlic.

  16. Determination of mercury distribution inside spent compact fluorescent lamps by atomic absorption spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rey-Raap, Natalia; Gallardo, Antonio, E-mail: gallardo@emc.uji.es

    Highlights: Black-Right-Pointing-Pointer New treatments for CFL are required considering the aim of Directive 202/96/CE. Black-Right-Pointing-Pointer It is shown that most of the mercury introduced into a CFL is in the phosphor powder. Black-Right-Pointing-Pointer Experimental conditions for microwave-assisted sample digestion followed by AAS measurements are described. Black-Right-Pointing-Pointer By washing the glass it is possible to reduce the concentration below legal limits. - Abstract: In this study, spent compact fluorescent lamps were characterized to determine the distribution of mercury. The procedure used in this research allowed mercury to be extracted in the vapor phase, from the phosphor powder, and the glass matrix.more » Mercury concentration in the three phases was determined by the method known as cold vapor atomic absorption spectrometry. Median values obtained in the study showed that a compact fluorescent lamp contained 24.52 {+-} 0.4 ppb of mercury in the vapor phase, 204.16 {+-} 8.9 ppb of mercury in the phosphor powder, and 18.74 {+-} 0.5 ppb of mercury in the glass matrix. There are differences in mercury concentration between the lamps since the year of manufacture or the hours of operation affect both mercury content and its distribution. The 85.76% of the mercury introduced into a compact fluorescent lamp becomes a component of the phosphor powder, while more than 13.66% is diffused through the glass matrix. By washing and eliminating all phosphor powder attached to the glass surface it is possible to classified the glass as a non-hazardous waste.« less

  17. Determination of total arsenic in fish by hydride-generation atomic absorption spectrometry: method validation, traceability and uncertainty evaluation

    NASA Astrophysics Data System (ADS)

    Nugraha, W. C.; Elishian, C.; Ketrin, R.

    2017-03-01

    Fish containing arsenic compound is one of the important indicators of arsenic contamination in water monitoring. The high level of arsenic in fish is due to absorption through food chain and accumulated in their habitat. Hydride generation (HG) coupled with atomic absorption spectrometric (AAS) detection is one of the most popular techniques employed for arsenic determination in a variety of matrices including fish. This study aimed to develop a method for the determination of total arsenic in fish by HG-AAS. The method for sample preparation from American of Analytical Chemistry (AOAC) Method 999.10-2005 was adopted for acid digestion using microwave digestion system and AOAC Method 986.15 - 2005 for dry ashing. The method was developed and validated using Certified Reference Material DORM 3 Fish Protein for trace metals for ensuring the accuracy and the traceability of the results. The sources of uncertainty of the method were also evaluated. By using the method, it was found that the total arsenic concentration in the fish was 45.6 ± 1.22 mg.Kg-1 with a coverage factor of equal to 2 at 95% of confidence level. Evaluation of uncertainty was highly influenced by the calibration curve. This result was also traceable to International Standard System through analysis of Certified Reference Material DORM 3 with 97.5% of recovery. In summary, it showed that method of preparation and HG-AAS technique for total arsenic determination in fish were valid and reliable.

  18. Atomic Absorption Spectroscopy. The Present and the Future.

    ERIC Educational Resources Information Center

    Slavin, Walter

    1982-01-01

    The status of current techniques and methods of atomic absorption (AA) spectroscopy (flame, hybrid, and furnace AA) is discussed, including limitations. Technological opportunities and how they may be used in AA are also discussed, focusing on automation, microprocessors, continuum AA, hybrid analyses, and others. (Author/JN)

  19. High efficiency transformation of banana [Musa acuminata L. cv. Matti (AA)] for enhanced tolerance to salt and drought stress through overexpression of a peanut salinity-induced pathogenesis-related class 10 protein.

    PubMed

    Rustagi, Anjana; Jain, Shalu; Kumar, Deepak; Shekhar, Shashi; Jain, Mukesh; Bhat, Vishnu; Sarin, Neera Bhalla

    2015-01-01

    Bananas and plantains (Musa spp. L.) are important subsistence crops and premium export commodity in several countries, and susceptible to a wide range of environmental and biotic stress conditions. Here, we report efficient, rapid, and reproducible Agrobacterium-mediated transformation and regeneration of an Indian niche cultivar of banana [M. acuminata cv. Matti (AA)]. Apical meristem-derived highly proliferative multiple shoot clump (MSC) explants were transformed with the Agrobacterium strain EHA105 harboring a binary vector pCAMBIA-1301 carrying hptII and uidA. Sequential agro-infiltration (10 min, 400 mmHg), infection (additional 35 min, Agrobacterium density A 600 = 0.8) and co-cultivation (18 h) regimen in 100 µM acetosyringone containing liquid medium were critical factors yielding high transformation efficiency (~81 %) corroborated by transient GUS expression assay. Stable transgenic events were recovered following two cycles of meristem initiation and selection on hygromycin containing medium. Histochemical GUS assay in several tissues of transgenic plants and molecular analyses confirmed stable integration and expression of transgene. The protocol described here allowed recovery of well-established putative transgenic plantlets in as little as 5 months. The transgenic banana plants could be readily acclimatized under greenhouse conditions, and were phenotypically similar to the wild-type untransformed control plants (WT). Transgenic plants overexpressing Salinity-Induced Pathogenesis-Related class 10 protein gene from Arachis hypogaea (AhSIPR10) in banana cv. Matti (AA) showed better photosynthetic efficiency and less membrane damage (P < 0.05) in the presence of NaCl and mannitol in comparison to WT plants suggesting the role of AhSIPR10 in better tolerance of salt stress and drought conditions.

  20. Determination of serum aluminum by electrothermal atomic absorption spectrometry: A comparison between Zeeman and continuum background correction systems

    NASA Astrophysics Data System (ADS)

    Kruger, Pamela C.; Parsons, Patrick J.

    2007-03-01

    Excessive exposure to aluminum (Al) can produce serious health consequences in people with impaired renal function, especially those undergoing hemodialysis. Al can accumulate in the brain and in bone, causing dialysis-related encephalopathy and renal osteodystrophy. Thus, dialysis patients are routinely monitored for Al overload, through measurement of their serum Al. Electrothermal atomic absorption spectrometry (ETAAS) is widely used for serum Al determination. Here, we assess the analytical performances of three ETAAS instruments, equipped with different background correction systems and heating arrangements, for the determination of serum Al. Specifically, we compare (1) a Perkin Elmer (PE) Model 3110 AAS, equipped with a longitudinally (end) heated graphite atomizer (HGA) and continuum-source (deuterium) background correction, with (2) a PE Model 4100ZL AAS equipped with a transversely heated graphite atomizer (THGA) and longitudinal Zeeman background correction, and (3) a PE Model Z5100 AAS equipped with a HGA and transverse Zeeman background correction. We were able to transfer the method for serum Al previously established for the Z5100 and 4100ZL instruments to the 3110, with only minor modifications. As with the Zeeman instruments, matrix-matched calibration was not required for the 3110 and, thus, aqueous calibration standards were used. However, the 309.3-nm line was chosen for analysis on the 3110 due to failure of the continuum background correction system at the 396.2-nm line. A small, seemingly insignificant overcorrection error was observed in the background channel on the 3110 instrument at the 309.3-nm line. On the 4100ZL, signal oscillation was observed in the atomization profile. The sensitivity, or characteristic mass ( m0), for Al at the 309.3-nm line on the 3110 AAS was found to be 12.1 ± 0.6 pg, compared to 16.1 ± 0.7 pg for the Z5100, and 23.3 ± 1.3 pg for the 4100ZL at the 396.2-nm line. However, the instrumental detection limits (3

  1. Determination of inorganic arsenic and its organic metabolites in urine by flow-injection hydride generation atomic absorption spectrometry.

    PubMed

    Hanna, C P; Tyson, J F; McIntosh, S

    1993-08-01

    A method has been developed for the determination of inorganic arsenic [As(III) and As(V)] and its organic metabolites (monomethylarsenic and dimethylarsenic) in urine by flow-injection hydride generation atomic absorption spectrometry. The nontoxic seafood-derived arsenobetaine and arsenocholine species were first separated by a solid-phase extraction procedure. The remaining sample was digested with a mixture of nitric and sulfuric acids and potassium dichromate, followed by attack with hydrogen peroxide. The resulting As(V) was reduced to As(III) with potassium iodide in hydrochloric acid before injection into the flow-injection manifold. The percentage analytical recoveries (mean +/- 95% confidence interval) of various arsenic species added to a urine specimen at 250 micrograms/L were 108 +/- 2, 112 +/- 11, 104 +/- 7, and 95 +/- 5 for As(III), As(V), monomethylarsenic, and dimethylarsenic, respectively. For the determination of arsenic in Standard Reference Material 2670 (toxic metals in human urine), results agreed with the certified value (480 +/- 100 micrograms/L). Analyses of samples for the Centre de Toxicologie du Quebec, containing seafood-derived species, demonstrated the viability of the separation procedure. Detection limits were between 0.1 and 0.2 microgram/L in the solution injected into the manifold, and precision at 10 micrograms/L was between 2% and 3% (CV). These preliminary results show that the method might be applicable to determinations of arsenic in a range of clinical urine specimens.

  2. [Determination of mercury in Boletus impolitus by flow injection-atomic absorption spectrometry].

    PubMed

    Li, Tao; Wang, Yuan-Zhong

    2008-04-01

    Various test conditions and effect factors for the determination of mercury by flow injection-atomic absorption spectrometry were discussed, and a method for the determination of mercury in Boletus impolitus has been developed. The linear range for mercury is 0-60 microg x L(-1). The relative standard deviation is less than 3.0%, and the recovery is 96%-107%. This method is simple, rapid and has been applied to the determination of mercury in Boletus impolitus samples with satisfactory results.

  3. Liquid chromatography-hydride generation-atomic absorption spectrometry for the speciation of tin in seafoods.

    PubMed

    Viñas, Pilar; López-García, Ignacio; Merino-Meroño, Beatriz; Campillo, Natalia; Hernández-Cordóba, Manuel

    2004-04-01

    Liquid chromatography with hydride generation atomic absorption spectrometry as the detection system was applied to the separation and determination of inorganic tin, tributyltin, dibutyltin, monobutyltin, diphenyltin and monophenyltin. A reversed phase C18 column and a methanol/water/acetic acid (70:27:3, v/v/v) mixture containing 0.05%(v/v) triethylamine and 0.1%(w/v) tropolone as the mobile phase (isocratic elution) were used. Extraction of organotins from the samples was carried out using methanol containing 0.05%(w/v) tropolone, a process that was repeated twice. The supernatants were shaken with water and dichloromethane in a separating funnel and the organic phase was collected and evaporated to dryness. When the method was applied to the speciation of tin in fresh and canned mussels, no organotins above the detection limits were identified in any of the samples, inorganic tin being the only species detected. The reliability of the procedure was checked by analyzing the total tin content of the samples by electrothermal atomic absorption spectrometry and by speciation of tin in a certified reference material, mussel tissue (CRM 477). The method can be used for environmental monitoring of organotins contaminated samples.

  4. Solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry for gold determination in geological samples after preconcentration onto carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Dobrowolski, Ryszard; Mróz, Agnieszka; Dąbrowska, Marzena; Olszański, Piotr

    2017-06-01

    A novelty method for the determination of gold in geological samples by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry (SS HR CS GF AAS) after solid-phase extraction onto modified carbon nanotubes (CNT) was described. The methodology developed is based on solid phase extraction of Au(III) ions from digested samples to eliminate strong interference caused by iron compounds and problems related to inhomogeneities of the samples. The use of aqueous or solid standard for calibration was studied and the slope of calibration curve was the same for both of these modes. This statement indicates the possibility to perform the calibration of the method using aqueous standard solutions. Under optimum conditions the absolute detection limit for gold was equal to 2.24 · 10- 6 μg g- 1 while the adsorption capacity of modified carbon nanotubes was 264 mg g- 1. The proposed procedure was validated by the application of certified reference materials (CRMs) with different content of gold and different matrix, the results were in good agreement with certified values. The method was successfully applied for separation and determination of gold ions in complex geological samples, with precision generally better than 8%.

  5. Mapping of lead, magnesium and copper accumulation in plant tissues by laser-induced breakdown spectroscopy and laser-ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kaiser, J.; Galiová, M.; Novotný, K.; Červenka, R.; Reale, L.; Novotný, J.; Liška, M.; Samek, O.; Kanický, V.; Hrdlička, A.; Stejskal, K.; Adam, V.; Kizek, R.

    2009-01-01

    Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) were utilized for mapping the accumulation of Pb, Mg and Cu with a resolution up to 200 μm in a up to cm × cm area of sunflower ( Helianthus annuus L.) leaves. The results obtained by LIBS and LA-ICP-MS are compared with the outcomes from Atomic Absorption Spectrometry (AAS) and Thin-Layer Chromatography (TLC). It is shown that laser-ablation based analytical methods can substitute or supplement these techniques mainly in the cases when a fast multi-elemental mapping of a large sample area is needed.

  6. Method validation for control determination of mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry.

    PubMed

    Torres, Daiane Placido; Martins-Teixeira, Maristela Braga; Cadore, Solange; Queiroz, Helena Müller

    2015-01-01

    A method for the determination of total mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) has been validated following international foodstuff protocols in order to fulfill the Brazilian National Residue Control Plan. The experimental parameters have been previously studied and optimized according to specific legislation on validation and inorganic contaminants in foodstuff. Linearity, sensitivity, specificity, detection and quantification limits, precision (repeatability and within-laboratory reproducibility), robustness as well as accuracy of the method have been evaluated. Linearity of response was satisfactory for the two range concentrations available on the TDA AAS equipment, between approximately 25.0 and 200.0 μg kg(-1) (square regression) and 250.0 and 2000.0 μg kg(-1) (linear regression) of mercury. The residues for both ranges were homoscedastic and independent, with normal distribution. Correlation coefficients obtained for these ranges were higher than 0.995. Limits of quantification (LOQ) and of detection of the method (LDM), based on signal standard deviation (SD) for a low-in-mercury sample, were 3.0 and 1.0 μg kg(-1), respectively. Repeatability of the method was better than 4%. Within-laboratory reproducibility achieved a relative SD better than 6%. Robustness of the current method was evaluated and pointed sample mass as a significant factor. Accuracy (assessed as the analyte recovery) was calculated on basis of the repeatability, and ranged from 89% to 99%. The obtained results showed the suitability of the present method for direct mercury measurement in fresh fish and shrimp samples and the importance of monitoring the analysis conditions for food control purposes. Additionally, the competence of this method was recognized by accreditation under the standard ISO/IEC 17025.

  7. Cadmium, copper, lead, and zinc determination in precipitation: A comparison of inductively coupled plasma atomic emission spectrometry and graphite furnace atomization atomic absorption spectrometry

    USGS Publications Warehouse

    Reddy, M.M.; Benefiel, M.A.; Claassen, H.C.

    1987-01-01

    Selected trace element analysis for cadmium, copper, lead, and zinc in precipitation samples by inductively coupled plasma atomic emission Spectrometry (ICP) and by atomic absorption spectrometry with graphite furnace atomization (AAGF) have been evaluated. This task was conducted in conjunction with a longterm study of precipitation chemistry at high altitude sites located in remote areas of the southwestern United States. Coefficients of variation and recovery values were determined for a standard reference water sample for all metals examined for both techniques. At concentration levels less than 10 micrograms per liter AAGF analyses exhibited better precision and accuracy than ICP. Both methods appear to offer the potential for cost-effective analysis of trace metal ions in precipitation. ?? 1987 Springer-Verlag.

  8. Conformational Specific Infrared and Ultraviolet Spectroscopy of Cold YA(D-Pro)AA\\cdotH+ Ions: a Sterochemical "twist" on the Proline Effect

    NASA Astrophysics Data System (ADS)

    Harrilal, Christopher P.; DeBlase, Andrew F.; Burke, Nicole L.; McLuckey, Scott A.; Zwier, Timothy S.

    2016-06-01

    The "proline effect" is a well-known fragmentation phenomenon in mass spectrometry, in which y-fragments are produced preferentially over b-fragments during the collision induced dissociation of protonated L-proline containing peptide ions. This specific fragmentation channel is favored because of the high basicity of the secondary amine intermediate and the ring instability in alternative bn+ products [ASMS 2014, 25, 1705]. In contrast, peptides containing the D-Pro stereoisomer have been shown to largely favor the production of b4+ ions over y3+ ions. This strongly suggests that differences in the conformational preferences between the D-Pro and L-Pro diastereomers are likely to be responsible but structural evidence has been lacking to date. Using tandem mass spectrometry and IR-UV double resonant action spectroscopy we are able to compare the 3D structures of cold [YA(D-Pro)AA+H]+ to [YA(L-Pro)AA+H]+ ions. The UV action spectra reveals two major conformers in [YA(D-Pro)AA+H]+ and one major conformer in [YA(L-Pro)AA+H]+. Clear differences in the hydrogen bonding patterns are apparent between the two conformers observed in the D-Pro specie which are both distinct from the L-Pro diastereomer. Furthermore, conformer and diastereomer specific photofragmentation patterns are observed. It is also noted that a ten-fold photofragment enhancement unique to one of the D-Pro conformers is observed upon absorption of a resonant IR photon after UV excitation. Differences in the excited state photophysics between the two D-Pro conformers suggest that vibrational excitation of S1 turns on coupling to the dissociative -Tyr channel in one conformer, while this coupling is already present in the vibronic ground state of the other. Calculated harmonic spectra (M052X/6-31+G*) of conformers obtained from Monte Carlo searches to the experimental spectra.

  9. Proteolysis of serum amyloid A and AA amyloid proteins by cysteine proteases: cathepsin B generates AA amyloid proteins and cathepsin L may prevent their formation

    PubMed Central

    Rocken, C; Menard, R; Buhling, F; Vockler, S; Raynes, J; Stix, B; Kruger, S; Roessner, A; Kahne, T

    2005-01-01

    Background: AA amyloidosis develops in patients with chronic inflammatory diseases. The AA amyloid proteins are proteolytic fragments obtained from serum amyloid A (SAA). Previous studies have provided evidence that endosomes or lysosomes might be involved in the processing of SAA, and contribute to the pathology of AA amyloidosis. Objective: To investigate the anatomical distribution of cathepsin (Cath) B and CathL in AA amyloidosis and their ability to process SAA and AA amyloid proteins. Methods and results: CathB and CathL were found immunohistochemically in every patient with AA amyloidosis and displayed a spatial relationship with amyloid in all the cases studied. Both degraded SAA and AA amyloid proteins in vitro. With the help of mass spectrometry 27 fragments were identified after incubation of SAA with CathB, nine of which resembled AA amyloid proteins, and seven fragments after incubation with CathL. CathL did not generate AA amyloid-like peptides. When native human AA amyloid proteins were used as a substrate 26 fragments were identified after incubation with CathB and 18 after incubation with CathL. Conclusion: The two most abundant and ubiquitously expressed lysosomal proteases can cleave SAA and AA amyloid proteins. CathB generates nine AA amyloid-like proteins by its carboxypeptidase activity, whereas CathL may prevent the formation of AA amyloid proteins by endoproteolytic activity within the N-terminal region of SAA. This is particularly interesting, because AA amyloidosis is a systemic disease affecting many organs and tissue types, almost all of which express CathB and CathL. PMID:15897303

  10. HP-41CV Flight Performance Advisory System (FPAS) for the E-2C, E-2B, and C-2A Aircraft

    DTIC Science & Technology

    1982-06-01

    NPS67-82- 003 NAVAL POSTGRADUATE SCHOOL Monterey, California DTIC HP-41CV FLIGHT PERFORMANCE ADVISORY SYSTEM (FPAS) FOR THE E-2C, E-2B, AND C-2A...A’P-𔃻"’f .00 ____________ 4. TITLE9 (and Subtil) SL TYPE OF REPORT & PERIOD COVERED H1P-41CV FLIGHT PERFORMANCE ADVISORY SYSTEM (FPAS) TECHNICAL REPORT...complement the original design of a Flight Performance Advisory System (FPAS) for the E-2C aircraft. The original design fulfilled the requirements of AE 3001

  11. Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectrometry Modelling Under Saturated Absorption

    NASA Astrophysics Data System (ADS)

    Dupré, Patrick

    2015-06-01

    The Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectrometry (NICE-OHMS) is a modern technique renowned for its ultimate sensitivity, because it combines long equivalent absorption length provided by a high finesse cavity, and a detection theoretically limited by the sole photon-shot-noise. One fallout of the high finesse is the possibility to accumulating strong intracavity electromagnetic fields (EMF). Under this condition, molecular transitions can be easy saturated giving rise to the usual Lamb dips (or hole burning). However, the unusual shape of the basically trichromatic EMF (due to the RF lateral sidebands) induces nonlinear couplings, i.e., new crossover transitions. An analytical methodology will be presented to calculate spectra provided by NICE-OHMS experiments. It is based on the solutions of the equations of motion of an open two-blocked-level system performed in the frequency-domain (optically thin medium). Knowing the transition dipole moment, the NICE-OHMS signals (``absorption-like'' and ``dispersion-like'') can be simulated by integration over the Doppler shifts and by paying attention to the molecular Zeeman sublevels and to the EMF polarization The approach has been validated by discussion experimental data obtained on two transitions of {C2H2} in the near-infrared under moderated saturation. One of the applications of the saturated absorption is to be able to simultaneously determine the transition intensity and the density number while only one these 2 quantities can only be assessed in nonlinear absorption. J. Opt. Soc. Am. B 32, 838 (2015) Optics Express 16, 14689 (2008)

  12. Mass Spectrometry Imaging proves differential absorption profiles of well-characterised permeability markers along the crypt-villus axis.

    PubMed

    Nilsson, Anna; Peric, Alexandra; Strimfors, Marie; Goodwin, Richard J A; Hayes, Martin A; Andrén, Per E; Hilgendorf, Constanze

    2017-07-25

    Knowledge about the region-specific absorption profiles from the gastrointestinal tract of orally administered drugs is a critical factor guiding dosage form selection in drug development. We have used a novel approach to study three well-characterized permeability and absorption marker drugs in the intestine. Propranolol and metoprolol (highly permeable compounds) and atenolol (low-moderate permeability compound) were orally co-administered to rats. The site of drug absorption was revealed by high spatial resolution matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) and complemented by quantitative measurement of drug concentration in tissue homogenates. MALDI-MSI identified endogenous molecular markers that illustrated the villi structures and confirmed the different absorption sites assigned to histological landmarks for the three drugs. Propranolol and metoprolol showed a rapid absorption and shorter transit distance in contrast to atenolol, which was absorbed more slowly from more distal sites. This study provides novel insights into site specific absorption for each of the compounds along the crypt-villus axis, as well as confirming a proximal-distal absorption gradient along the intestine. The combined analytical approach allowed the quantification and spatial resolution of drug distribution in the intestine and provided experimental evidence for the suggested absorption behaviour of low and highly permeable compounds.

  13. Analysis of metal-laden water via portable X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Pearson, Delaina; Weindorf, David C.; Chakraborty, Somsubhra; Li, Bin; Koch, Jaco; Van Deventer, Piet; de Wet, Jandre; Kusi, Nana Yaw

    2018-06-01

    A rapid method for in-situ elemental composition analysis of metal-laden water would be indispensable for studying polluted water. Current analytical lab methods to determine water quality include flame atomic absorption spectrometry (FAAS), atomic absorption spectrophotometry (AAS), electrothermal atomic absorption spectrometry (EAAS), and inductively coupled plasma (ICP) spectroscopy. However only two field methods, colorimetry and absorptiometry, exist for elemental analysis of water. Portable X-ray fluorescence (PXRF) spectrometry is an effective method for elemental analysis of soil, sediment, and other matrices. However, the accuracy of PXRF is known to be affected while scanning moisture-laden soil samples. This study sought to statistically establish PXRF's predictive ability for various elements in water at different concentrations relative to inductively coupled plasma atomic emission spectroscopy (ICP-AES). A total of 390 metal-laden water samples collected from leaching columns of mine tailings in South Africa were analyzed via PXRF and ICP-AES. The PXRF showed differential effectiveness in elemental quantification. For the collected water samples, the best relationships between ICP and PXRF elemental data were obtained for K and Cu (R2 = 0.92). However, when scanning ICP calibration solutions with elements in isolation, PXRF results indicated near perfect agreement; Ca, K, Fe, Cu and Pb produced an R2 of 0.99 while Zn and Mn produced an R2 of 1.00. The utilization of multiple PXRF (stacked) beams produced stronger correlation to ICP relative to the use of a single beam in isolation. The results of this study demonstrated the PXRF's ability to satisfactorily predict the composition of metal-laden water as reported by ICP for several elements. Additionally this study indicated the need for a "Water Mode" calibration for the PXRF and demonstrates the potential of PXRF for future study of polluted or contaminated waters.

  14. [Evaluation of uncertainty for determination of tin and its compounds in air of workplace by flame atomic absorption spectrometry].

    PubMed

    Wei, Qiuning; Wei, Yuan; Liu, Fangfang; Ding, Yalei

    2015-10-01

    To investigate the method for uncertainty evaluation of determination of tin and its compounds in the air of workplace by flame atomic absorption spectrometry. The national occupational health standards, GBZ/T160.28-2004 and JJF1059-1999, were used to build a mathematical model of determination of tin and its compounds in the air of workplace and to calculate the components of uncertainty. In determination of tin and its compounds in the air of workplace using flame atomic absorption spectrometry, the uncertainty for the concentration of the standard solution, atomic absorption spectrophotometer, sample digestion, parallel determination, least square fitting of the calibration curve, and sample collection was 0.436%, 0.13%, 1.07%, 1.65%, 3.05%, and 2.89%, respectively. The combined uncertainty was 9.3%.The concentration of tin in the test sample was 0.132 mg/m³, and the expanded uncertainty for the measurement was 0.012 mg/m³ (K=2). The dominant uncertainty for determination of tin and its compounds in the air of workplace comes from least squares fitting of the calibration curve and sample collection. Quality control should be improved in the process of calibration curve fitting and sample collection.

  15. Determination of copper and mercury in phosphate fertilizers employing direct solid sampling analysis and high resolution continuum source graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    de Oliveira Souza, Sidnei; François, Luciane Luiza; Borges, Aline Rocha; Vale, Maria Goreti Rodrigues; Araujo, Rennan Geovanny Oliveira

    2015-12-01

    The present study proposes the determination of copper and mercury in phosphate fertilizers by direct solid sampling analysis (SS) employing high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). For Cu determination, two analytical lines were used: 327.3960 nm and 249.2146 nm. Hg determination was carried out on the line 253.6521 nm and 100 μg KMnO4 was used as chemical modifier. The optimal pyrolysis temperature for Cu determination was 1300 °C. Atomization temperatures for Cu and Hg were 2400 and 1100 °C, respectively. External calibration with aqueous standard solutions was adopted for both elements. The limits of quantification (LoQs) and characteristic mass (m0) obtained for Cu determination were 0.4 μg g- 1 and 1.12 ng, respectively, on line 249.2146 nm, and 64 μg g- 1 and 25 pg on 327.3960 nm. For mercury, LoQ and m0 were 4.8 ng g- 1 and 39 pg, respectively. The accuracy of the proposed methods was confirmed by the analysis of standard reference material (SRM) of Trace Elements in Multi-Nutrient Fertilizer (SRM NIST 695). The precision expressed as relative standard deviation (RSD), was better than 8.2% for Hg and 7.7% for the Cu (n = 5), considered satisfactory for microanalysis in solid sample. Four fertilizer samples acquired in commercial establishments in the city of Salvador, Bahia, Brazil, were analyzed. The optimized analytical methods were simple, fast, accurate, precise and free of spectral interferences for the determination of Cu and Hg in phosphate fertilizer samples by SS-HR-CS GF AAS, avoiding the dissolution of the sample, the use of harmful reagents and the generation of residues.

  16. Determination of Chlorine in Milk via Molecular Absorption of SrCl Using High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry.

    PubMed

    Ozbek, Nil; Akman, Suleyman

    2016-07-20

    Total chlorine in milk was determined via the molecular absorption of diatomic strontium monochloride at 635.862 nm using high-resolution continuum source graphite furnace atomic absorption spectrometry. The effects of coating the graphite furnace, using different modifiers, amount of molecule-forming element, and different calibrants were investigated and optimized. Chlorine concentrations in milk samples were determined in a Zr-coated graphite furnace using 25 μg of Sr as the molecule-forming reagent and applying a pyrolysis temperature of 600 °C and a molecule-forming temperature of 2300 °C. Linearity was maintained up to 500 μg mL(-1) of Cl. The method was tested by analyzing a certified reference wastewater. The results were in the uncertainty limits of the certified value. The limit of detection of the method was 1.76 μg mL(-1). The chlorine concentrations in various cow milk samples taken from the market were found in the range of 588-1472 mg L(-1).

  17. Determination of selected elements in whole coal and in coal ash from the eight argonne premium coal samples by atomic absorption spectrometry, atomic emission spectrometry, and ion-selective electrode

    USGS Publications Warehouse

    Doughten, M.W.; Gillison, J.R.

    1990-01-01

    Methods for the determination of 24 elements in whole coal and coal ash by inductively coupled argon plasma-atomic emission spectrometry, flame, graphite furnace, and cold vapor atomic absorption spectrometry, and by ion-selective electrode are described. Coal ashes were analyzed in triplicate to determine the precision of the methods. Results of the analyses of NBS Standard Reference Materials 1633, 1633a, 1632a, and 1635 are reported. Accuracy of the methods is determined by comparison of the analysis of standard reference materials to their certified values as well as other values in the literature.

  18. Highly efficient Agrobacterium-mediated transformation of embryogenic cell suspensions of Musa acuminata cv. Mas (AA) via a liquid co-cultivation system.

    PubMed

    Huang, Xia; Huang, Xue-Lin; Xiao, Wang; Zhao, Jie-Tang; Dai, Xue-Mei; Chen, Yun-Feng; Li, Xiao-Ju

    2007-10-01

    A high efficient protocol of Agrobacterium-mediated transformation of Musa acuminata cv. Mas (AA), a major banana variety of the South East Asia region, was developed in this study. Male-flower-derived embryogenic cell suspensions (ECS) were co-cultivated in liquid medium with Agrobacterium strain EHA105 harboring a binary vector pCAMBIA2301 carrying nptII and gusA gene in the T-DNA. Depending upon conditions and duration of co-cultivation in liquid medium, 0-490 transgenic plants per 0.5 ml packed cell volume (PCV) of ECS were obtained. The optimum duration of inoculation was 2 h, and the highest transformation frequency was achieved when infected ECS were co-cultivated in liquid medium first for 12 h at 40 rpm and then for 156 h at 100 rpm on a rotary shaker. Co-cultivation for a shorter duration (72 h) or shaking constantly at 100 rpm at the same duration gave 1.6 and 1.8 folds lower transformation efficiency, respectively. No transgenic plants were obtained in parallel experiments carried on semi-solid media. Histochemical GUS assay and molecular analysis in several tissues of the transgenic plants demonstrated that foreign genes were stably integrated into the banana genome. Compared to semi-solid co-cultivation transformation in other banana species, it is remarkable that liquid co-cultivation was much more efficient for transformation of the Mas cultivar, and was at least 1 month faster for regenerating transgenic plants.

  19. Speciation of chromium (VI) and total chromium determination in welding dust samples by flow-injection analysis coupled to atomic absorption spectrometry.

    PubMed

    Girard, L; Hubert, J

    1996-11-01

    We have studied the speciation of chromium (VI) in stainless-steel welding dusts. The approach used for the analysis of Cr(VI) and total Cr relies on a flow-injection analyzer (FIA) equipped with two different sequential detectors. The system measures Cr(VI). by colorimetry (with 1,5-diphenyl carbohydrazide) and total chromium content by flame atomic absorption spectroscopy (AAS). The extraction of the samples of welding-fume dusts is achieved in a buffer solution (acetic acid and sodium acetate at pH 4). This extraction procedure gives a 96% recovery of chromium (VI). The FIA-AAS system that has been described is also more sensitive, has a lower detection limit (0.005 mug ml(-1)) and gives a better precision (< 1%) than other equivalent systems that have been previously described.

  20. Solid sampling determination of magnesium in lithium niobate crystals by graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Dravecz, Gabriella; Laczai, Nikoletta; Hajdara, Ivett; Bencs, László

    2016-12-01

    The vaporization/atomization processes of Mg in high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS) were investigated by evaporating solid (powder) samples of lithium niobate (LiNbO3) optical single crystals doped with various amounts of Mg in a transversally heated graphite atomizer (THGA). Optimal analytical conditions were attained by using the Mg I 215.4353 nm secondary spectral line. An optimal pyrolysis temperature of 1500 °C was found for Mg, while the compromise atomization temperature in THGAs (2400 °C) was applied for analyte vaporization. The calibration was performed against solid (powered) lithium niobate crystal standards. The standards were prepared with exactly known Mg content via solid state fusion of the oxide components of the matrix and analyte. The correlation coefficient (R value) of the linear calibration was not worse than 0.9992. The calibration curves were linear in the dopant concentration range of interest (0.74-7.25 mg/g Mg), when dosing 3-10 mg of the powder samples into the graphite sample insertion boats. The Mg content of the studied 19 samples was in the range of 1.69-4.13 mg/g. The precision of the method was better than 6.3%. The accuracy of the results was verified by means of flame atomic absorption spectrometry with solution sample introduction after digestion of several crystal samples.

  1. Multianalytical determination of trace elements in atmospheric biomonitors by k0-INAA, ICP-MS and AAS

    NASA Astrophysics Data System (ADS)

    Freitas, M. C.; Pacheco, A. M. G.; Dionísio, I.; Sarmento, S.; Baptista, M. S.; Vasconcelos, M. T. S. D.; Cabral, J. P.

    2006-08-01

    Elemental contents of atmospheric biomonitors—epiphytic lichens and tree bark, exposed in continuous and discontinuous modes—have been assessed through k0-standardised instrumental neutron activation analysis ( k0-INAA) (two different institutions), inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS). Certified reference materials—ISE-921 (river clay), NIST-1547 (peach leaves), ICHTJ-INCT-TL-1 (tea leaves; TL-1 hereinafter) and IAEA-336 (lichen material), and nonparametric statistics—rank-order correlations (Spearman RS) and enhanced-sign tests (Wilcoxon T)—were used for analytical control and data comparison, respectively. In general, quality of procedures was deemed good, except for k0-INAA in determining Br, Cu and Na, all likely affected by high counting statistics, and/or contamination issues (the latter). Results for Cu, Ni, Pb and Sr (by both ICP-MS and AAS) revealed that, despite an outstanding correlation (asymptotic p=0.000), they could be viewed as statistically equal for Cu only: AAS tended to yield higher values for Pb and Ni, and lower ones for Sr. The comparison between ICP-MS and k0-INAA data from TUDelft, for Al, Ca, Cu, Mg, Mn, Na, Ti and V, showed an excellent correlation (as above) and random (relative) magnitude for Cu, Mg, Mn and Ti only: ICP-MS tended to yield higher values for Al, Na and V, and lower ones for Ca, whereas between k0-INAA data from TUDelft and ITN, for Br, Ca and Na, resulted in systematically higher [Br] and [Ca] variates from TUDelft, even if all corresponding data sets were found to correlate at stringent significance levels. In a few cases, though—Ca, Sr in lichens; Pb in bark—matrix effects did appear to interfere in the outcome of matched-pairs, signed-rank tests, since random hierarchy of variates could be asserted just when lichen and bark data sets were processed separately.

  2. Measurements of sulfur compounds in CO 2 by diode laser atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Franzke, J.; Stancu, D. G.; Niemax, K.

    2003-07-01

    Two simple methods for the analysis of the total concentration of sulfur in CO 2 by diode laser atomic absorption spectrometry of excited, metastable sulfur atoms in a direct current discharge are presented. In the first method, the CO 2 sample gas is mixed with the plasma gas (Ar or He) while the second is based on reproducible measurements of the sulfur released from the walls in a helium discharge after being deposited as a result of operating the discharge in pure CO 2 sample gas. The detection limits obtained satisfy the requirements for the control of sulfur compounds in CO 2 used in the food and beverage industry.

  3. Targeting SVCT for enhanced drug absorption: Synthesis and in vitro evaluation of a novel vitamin C conjugated prodrug of saquinavir

    PubMed Central

    Luo, Shuanghui; Wang, Zhiying; Patel, Mitesh; Khurana, Varun; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim. K.

    2015-01-01

    In order to improve oral absorption, a novel prodrug of saquinavir (Saq), ascorbyl-succinic-saquinavir (AA-Su-Saq) targeting sodium dependent vitamin C transporter (SVCT) was synthesized and evaluated. Aqueous solubility, stability and cytotoxicity were determined. Affinity of AA-Su-Saq towards effluxpump P-glycoprotein (P-gp) and recognition of AA-Su-Saq by SVCT were studied. Transepithelial permeability across polarized MDCK-MDR1 and Caco-2 cells were determined. Metabolic stability of AA-Su-Saq in rat liver microsomes was investigated. AA-Su-Saq appears to be fairly stable in both DPBS and Caco-2 cells with half lives of 9.65 and 5.73 h, respectively. Uptake of [3H]Saquinavir accelerated by 2.7 and 1.9 fold in the presence of 50 μM Saq and AA-Su-Saq in MDCK-MDR1 cells. Cellular accumulation of [14C]AA diminished by about 50–70% relative to control in the presence of 200 μM AA-Su-Saq in MDCK-MDR1 and Caco-2 cells. Uptake of AA-Su-Saq was lowered by 27% and 34% in the presence of 5 mM AA in MDCK-MDR1 and Caco-2 cells, respectively. Absorptive permeability of AA-Su-Saq was elevated about 4-5 fold and efflux index reduced by about 13-15 fold across the polarized MDCK-MDR1 and Caco-2 cells. Absorptive permeability of AA-Su-Saq decreased 44% in the presence of 5 mM AA across MDCK-MDR1 cells. AA-Su-Saq was devoid of cytotoxicity over the concentration range studied. AA-Su-Saq significantly enhanced the metabolic stability but lowered the affinity towards CYP3A4. In conclusion, prodrug modification of Saq through conjugation to AA via a linker significantly raised the absorptive permeability and metabolic stability. Such modification also caused significant evading of P-gp mediated efflux and CYP3A4 mediated metabolism. SVCT targeted prodrug approach can be an attractive strategy to enhance the oral absorption and systemic bioavailability of anti-HIV protease inhibitors. PMID:21571053

  4. Determination of sub-ng g-1 levels of total inorganic arsenic and selenium in foods by hydride-generation atomic absorption spectrometry after pre-concentration.

    PubMed

    Altunay, Nail; Gürkan, Ramazan

    2017-03-01

    A new and simple ultrasonic-assisted extraction (UAE) procedure was developed for the determination of inorganic arsenic and selenium in foods by hydride-generation atomic absorption spectrometry (HG-AAS). The various analytical variables affecting complex formation and extraction efficiency were investigated and optimised. The method is based on selective complex formation of As(III) and Se(IV) in the presence of excess As(V) and Se(VI) with toluidine red in the presence of tartaric acid at pH 4.5, and then extraction of the resulting condensation products into the micellar phase of non-ionic surfactant, polyethylene glycol dodecyl ether, Brij 35. Under optimised conditions, good linear relationships were obtained in the ranges of 4-225 and 12-400 ng l - 1 with limits of detection of 1.1 and 3.5 ng l - 1 for As(III) and Se(IV), respectively. The repeatability was better than 3.9% for both analytes (n = 10, 25 ng l - 1 ) while reproducibility ranged from 4.2% to 4.8%. The recoveries of As(III) and Se(IV) spiked at 25-100 ng l - 1 were in the range of 94.2-104.8%. After pre-concentration of a 5.0 ml sample, the sensitivity enhancement factors for As(III) and Se(IV) were 185 and 140, respectively. Accuracy was assessed by analysis of two standard reference materials (SRMs) and spiked recovery experiments. The method was successfully applied to the accurate and reliable determination of total As and total Se by HG-AAS after pre-reduction with a mixture of L-cysteine and tartaric acid. Finally, the method was shown to be rapid and sensitive, with good results for extraction, pre-concentration and determination of total As and Se contents (as As(III) and Se(IV)) from food samples.

  5. Colorimetric and atomic absorption spectrometric determination of mucolytic drug ambroxol through ion-pair formation with iron and thiocyanate.

    PubMed

    Levent, Abdulkadir; Sentürk, Zühre

    2010-09-01

    Colorimetric and atomic absorption spectrometric methods have been developed for the determination of mucolytic drug Ambroxol. These procedures depend upon the reaction of iron(III) metal ion with the drug in the presence of thiocyanate ion to form stable ion-pair complex which extractable chloroform. The red-coloured complex was determined either colorimetrically at 510 nm or by indirect atomic absorption spectrometry (AAS) via the determination of the iron content in the formed complex. The optimum experimental conditions for pH, concentrations of Fe(3+) and SCN(-), shaking time, phase ratio, and the number of extractions were determined. Under the proposed conditions, linearity was obeyed in the concentration ranges 4.1x10(-6) - 5.7x10(-5) M (1.7-23.6 µg mL(-1)) using both methods, with detection limits of 4.6x10(-7) M (0.19 µg mL(-1)) for colorimetry and 1.1x10(-6) M (0.46 µg mL(-1)) for AAS. The proposed methods were applied for the determination of Ambroxol in tablet dosage forms. The results obtained were statistically analyzed and compared with those obtained by applying the high-performance liquid chromatographic method with diode-array detection.

  6. Speciation analysis of arsenic in biological matrices by automated hydride generation-cryotrapping-atomic absorption spectrometry with multiple microflame quartz tube atomizer (multiatomizer).

    EPA Science Inventory

    This paper describes an automated system for the oxidation state specific speciation of inorganic and methylated arsenicals by selective hydride generation - cryotrapping- gas chromatography - atomic absorption spectrometry with the multiatomizer. The corresponding arsines are ge...

  7. High purity polyimide analysis by solid sampling graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Santos, Rafael F.; Carvalho, Gabriel S.; Duarte, Fabio A.; Bolzan, Rodrigo C.; Flores, Erico M. M.

    2017-03-01

    In this work, Cr, Cu, Mn, Na and Ni were determined in high purity polyimides (99.5%) by solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) using Zeeman effect background correction system with variable magnetic field, making possible the simultaneous measurement at high or low sensitivity. The following analytical parameters were evaluated: pyrolysis and atomization temperatures, feasibility of calibration with aqueous solution, linear calibration range, sample mass range and the use of chemical modifier. Calibration with aqueous standard solutions was feasible for all analytes. No under or overestimated results were observed and up to 10 mg sample could be introduced on the platform for the determination of Cr, Cu, Mn, Na and Ni. The relative standard deviation ranged from 3 to 20%. The limits of detection (LODs) achieved using the high sensitivity mode were as low as 7.0, 2.5, 1.7, 17 and 0.12 ng g- 1 for Cr, Cu, Mn, Na and Ni, respectively. No addition of chemical modifier was necessary, except for Mn determination where Pd was required. The accuracy was evaluated by analyte spike and by comparison of the results with those obtained by inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry after microwave-assisted digestion in a single reaction chamber system and also by neutron activation analysis. No difference among the results obtained by SS-GFAAS and those obtained by alternative analytical methods using independent techniques. SS-GFAAS method showed some advantages, such as the determination of metallic contaminants in high purity polyimides with practically no sample preparation, very low LODs, calibration with aqueous standards and determination in a wide range of concentration.

  8. Comparison of two methods for blood lead analysis in cattle: graphite-furnace atomic absorption spectrometry and LeadCare(R) II system.

    PubMed

    Bischoff, Karyn; Gaskill, Cynthia; Erb, Hollis N; Ebel, Joseph G; Hillebrandt, Joseph

    2010-09-01

    The current study compared the LeadCare(R) II test kit system with graphite-furnace atomic absorption spectrometry for blood lead (Pb) analysis in 56 cattle accidentally exposed to Pb in the field. Blood Pb concentrations were determined by LeadCare II within 4 hr of collection and after 72 hr of refrigeration. Blood Pb concentrations were determined by atomic absorption spectrometry, and samples that were coagulated (n = 12) were homogenized before analysis. There was strong rank correlation (R(2) = 0.96) between atomic absorption and LeadCare II (within 4 hr of collection), and a conversion formula was determined for values within the observed range (3-91 mcg/dl, although few had values >40 mcg/dl). Median and mean blood pb concentrations for atomic absorption were 7.7 and 15.9 mcg/dl, respectively; for LeadCare II, medians were 5.2 mcg/dl at 4 hr and 4.9 mcg/dl at 72 hr, and means were 12.4 and 11.7, respectively. LeadCare II results at 4 hr strongly correlated with 72 hr results (R(2) = 0.96), but results at 72 hr were lower (P < 0.01). There was no significant difference between coagulated and uncoagulated samples run by atomic absorption. Although there have been several articles that compared LeadCare with other analytical techniques, all were for the original system, not LeadCare II. The present study indicated that LeadCare II results correlated well with atomic absorption over a wide range of blood Pb concentrations and that refrigerating samples for up to 72 hr before LeadCare II analysis was acceptable for clinical purposes.

  9. Automation of preparation of nonmetallic samples for analysis by atomic absorption and inductively coupled plasma spectrometry

    NASA Technical Reports Server (NTRS)

    Wittmann, A.; Willay, G.

    1986-01-01

    For a rapid preparation of solutions intended for analysis by inductively coupled plasma emission spectrometry or atomic absorption spectrometry, an automatic device called Plasmasol was developed. This apparatus used the property of nonwettability of glassy C to fuse the sample in an appropriate flux. The sample-flux mixture is placed in a composite crucible, then heated at high temperature, swirled until full dissolution is achieved, and then poured into a water-filled beaker. After acid addition, dissolution of the melt, and filling to the mark, the solution is ready for analysis. The analytical results obtained, either for oxide samples or for prereduced iron ores show that the solutions prepared with this device are undistinguished from those obtained by manual dissolutions done by acid digestion or by high temperature fusion. Preparation reproducibility and analytical tests illustrate the performance of Plasmasol.

  10. Targeting SVCT for enhanced drug absorption: synthesis and in vitro evaluation of a novel vitamin C conjugated prodrug of saquinavir.

    PubMed

    Luo, Shuanghui; Wang, Zhiying; Patel, Mitesh; Khurana, Varun; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim K

    2011-07-29

    In order to improve oral absorption, a novel prodrug of saquinavir (Saq), ascorbyl-succinic-saquinavir (AA-Su-Saq) targeting sodium dependent vitamin C transporter (SVCT) was synthesized and evaluated. Aqueous solubility, stability and cytotoxicity were determined. Affinity of AA-Su-Saq towards efflux pump P-glycoprotein (P-gp) and recognition of AA-Su-Saq by SVCT were studied. Transepithelial permeability across polarized MDCK-MDR1 and Caco-2 cells were determined. Metabolic stability of AA-Su-Saq in rat liver microsomes was investigated. AA-Su-Saq appears to be fairly stable in both DPBS and Caco-2 cells with half lives of 9.65 and 5.73 h, respectively. Uptake of [(3)H]Saquinavir accelerated by 2.7 and 1.9 fold in the presence of 50 μM Saq and AA-Su-Saq in MDCK-MDR1 cells. Cellular accumulation of [(14)C]AA diminished by about 50-70% relative to control in the presence of 200 μM AA-Su-Saq in MDCK-MDR1 and Caco-2 cells. Uptake of AA-Su-Saq was lowered by 27% and 34% in the presence of 5mM AA in MDCK-MDR1 and Caco-2 cells, respectively. Absorptive permeability of AA-Su-Saq was elevated about 4-5 fold and efflux index reduced by about 13-15 fold across the polarized MDCK-MDR1 and Caco-2 cells. Absorptive permeability of AA-Su-Saq decreased 44% in the presence of 5mM AA across MDCK-MDR1 cells. AA-Su-Saq was devoid of cytotoxicity over the concentration range studied. AA-Su-Saq significantly enhanced the metabolic stability but lowered the affinity towards CYP3A4. In conclusion, prodrug modification of Saq through conjugation to AA via a linker significantly raised the absorptive permeability and metabolic stability. Such modification also caused significant evading of P-gp mediated efflux and CYP3A4 mediated metabolism. SVCT targeted prodrug approach can be an attractive strategy to enhance the oral absorption and systemic bioavailability of anti-HIV protease inhibitors. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Antibiotic toxicity and absorption in zebrafish using liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Fan; Qin, Wei; Zhang, Jing-Pu; Hu, Chang-Qin

    2015-01-01

    Evaluation of drug toxicity is necessary for drug safety, but in vivo drug absorption is varied; therefore, a rapid, sensitive and reliable method for measuring drugs is needed. Zebrafish are acceptable drug toxicity screening models; we used these animals with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in a multiple reaction monitoring mode to quantify drug uptake in zebrafish to better estimate drug toxicity. Analytes were recovered from zebrafish homogenate by collecting supernatant. Measurements were confirmed for drugs in the range of 10-1,000 ng/mL. Four antibiotics with different polarities were tested to explore any correlation of drug polarity, absorption, and toxicity. Zebrafish at 3 days post-fertilization (dpf) absorbed more drug than those at 6 h post-fertilization (hpf), and different developmental periods appeared to be differentially sensitive to the same compound. By observing abnormal embryos and LD50 values, zebrafish embryos at 6 hpf were considered to be suitable for evaluating embryotoxicity. Also, larvae at 3 dpf were adapted to measure acute drug toxicity in adult mammals. Thus, we can exploit zebrafish to study drug toxicity and can reliably quantify drug uptake with LC-MS/MS. This approach will be helpful for future studies of toxicology in zebrafish.

  12. A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family

    PubMed Central

    Mollerup, Filip; Parikka, Kirsti; Koutaniemi, Sanna; Boer, Harry; Juvonen, Minna; Master, Emma; Tenkanen, Maija; Kruus, Kristiina

    2017-01-01

    ABSTRACT We describe here the identification and characterization of a copper radical oxidase from auxiliary activities family 5 (AA5_2) that was distinguished by showing preferential activity toward raffinose. Despite the biotechnological potential of carbohydrate oxidases from family AA5, very few members have been characterized. The gene encoding raffinose oxidase from Colletotrichum graminicola (CgRaOx; EC 1.1.3.−) was identified utilizing a bioinformatics approach based on the known modular structure of a characterized AA5_2 galactose oxidase. CgRaOx was expressed in Pichia pastoris, and the purified enzyme displayed the highest activity on the trisaccharide raffinose, whereas the activity on the disaccharide melibiose was three times lower and more than ten times lower activity was detected on d-galactose at a 300 mM substrate concentration. Thus, the substrate preference of CgRaOx was distinguished clearly from the substrate preferences of the known galactose oxidases. The site of oxidation for raffinose was studied by 1H nuclear magnetic resonance and mass spectrometry, and we confirmed that the hydroxyl group at the C-6 position was oxidized to an aldehyde and that in addition uronic acid was produced as a side product. A new electrospray ionization mass spectrometry method for the identification of C-6 oxidized products was developed, and the formation mechanism of the uronic acid was studied. CgRaOx presented a novel activity pattern in the AA5 family. IMPORTANCE Currently, there are only a few characterized members of the CAZy AA5 protein family. These enzymes are interesting from an application point of view because of their ability to utilize the cheap and abundant oxidant O2 without the requirement of complex cofactors such as FAD or NAD(P). Here, we present the identification and characterization of a novel AA5 member from Colletotrichum graminicola. As discussed in the present study, the bioinformatics approach using the modular structure of

  13. Liquid-phase microextraction combined with graphite furnace atomic absorption spectrometry: A review.

    PubMed

    de la Calle, Inmaculada; Pena-Pereira, Francisco; Lavilla, Isela; Bendicho, Carlos

    2016-09-14

    An overview of the combination of liquid-phase microextraction (LPME) techniques with graphite furnace atomic absorption spectrometry (GFAAS) is reported herein. The high sensitivity of GFAAS is significantly enhanced by its association with a variety of miniaturized solvent extraction approaches. LPME-GFAAS thus represents a powerful combination for determination of metals, metalloids and organometallic compounds at (ultra)trace level. Different LPME modes used with GFAAS are briefly described, and the experimental parameters that show an impact in those microextraction processes are discussed. Special attention is paid to those parameters affecting GFAAS analysis. Main issues found when coupling LPME and GFAAS, as well as those strategies reported in the literature to solve them, are summarized. Relevant applications published on the topic so far are included. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Quantification of the fluorine containing drug 5-fluorouracil in cancer cells by GaF molecular absorption via high-resolution continuum source molecular absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Krüger, Magnus; Huang, Mao-Dong; Becker-Roß, Helmut; Florek, Stefan; Ott, Ingo; Gust, Ronald

    The development of high-resolution continuum source molecular absorption spectrometry made the quantification of fluorine feasible by measuring the molecular absorption as gallium monofluoride (GaF). Using this new technique, we developed on the example of 5-fluorouracil (5-FU) a graphite furnace method to quantify fluorine in organic molecules. The effect of 5-FU on the generation of the diatomic GaF molecule was investigated. The experimental conditions such as gallium nitrate amount, temperature program, interfering anions (represented as corresponding acids) and calibration for the determination of 5-FU in standard solution and in cellular matrix samples were investigated and optimized. The sample matrix showed no effect on the sensitivity of GaF molecular absorption. A simple calibration curve using an inorganic sodium fluoride solution can conveniently be used for the calibration. The described method is sensitive and the achievable limit of detection is 0.23 ng of 5-FU. In order to establish the concept of "fluorine as a probe in medicinal chemistry" an exemplary application was selected, in which the developed method was successfully demonstrated by performing cellular uptake studies of the 5-FU in human colon carcinoma cells.

  15. Chemical Composition and in Vitro Antimicrobial, Cytotoxic, and Central Nervous System Activities of the Essential Oils of Citrus medica L. cv. 'Liscia' and C. medica cv. 'Rugosa' Cultivated in Southern Italy.

    PubMed

    Aliberti, Luigi; Caputo, Lucia; De Feo, Vincenzo; De Martino, Laura; Nazzaro, Filomena; Souza, Lucéia Fátima

    2016-09-18

    Citrus medica cv. 'liscia' and C. medica cv. 'rugosa' are two taxa of citron, belonging to the biodiversity of South Italy, in particular of Amalfi Coast, in the Campania region. The chemical composition of the essential oils (EOs) from fruit peels of both C. medica cultivars was studied by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses. In all, 100 compounds were identified, 82 for C. medica cv. 'liscia', accounting for 91.4% of the total oil, and 88 for C. medica cv. 'rugosa', accounting for 92.0% of the total oil. Monoterpene hydrocarbons are the main constituents in both oils of C. medica cv. 'liscia' (79.1%) and C. medica cv. 'rugosa' (80.2%). In both oils, limonene (67.2%-62.8%) and camphene (8.5%-10.9%) are the main constituents. The antimicrobial activity of the EOs was assayed against some bacterial strains: Bacillus cereus (DSM 4313), Bacillus cereus (DSM 4384), Staphylococcus aureus (DSM 25693), Pseudomonas aeruginosa (ATCC 50071), and Escherichia coli (DSM 8579). Low concentrations of C. medica cv. 'rugosa' EO showed an inhibitory effect on P. aeruginosa and higher concentrations inhibited more B. cereus (4384) and E. coli than S. aureus. The cytotoxicity of the EO was evaluated against SH-SY5Y cell line. The influence of the EO on the expression of adenylate cyclase 1 (ADCY1) was also studied. The antimicrobial activity registered confirm their traditional uses as food preserving agents and led us to hypothesize the possible use of these oils as antimicrobials. The alterations in ADCY1 expression suggested a role for limonene in effects on the central nervous system.

  16. Determination of Sodium, Potassium, Magnesium, and Calcium Minerals Level in Fresh and Boiled Broccoli and Cauliflower by Atomic Absorption Spectrometry

    NASA Astrophysics Data System (ADS)

    Nerdy

    2018-01-01

    Vegetables from the cabbage family vegetables consumed by many people, which is known healthful, by eaten raw, boiled, or cooked (stir fry or soup). Vegetables like broccoli and cauliflower contain vitamins, minerals, and fiber. This study aims to determine the decrease percentage of sodium, potassium, magnesium, and calcium minerals level caused by boiled broccoli and cauliflower by atomic absorption spectrometry. Boiled broccoli and cauliflower prepared by given boiled treatment in boiling water for 3 minutes. Fresh and boiled broccoli and cauliflower carried out dry destruction, followed by quantitative analysis of sodium, potassium, magnesium, and calcium minerals respectively at a wavelength of 589.0 nm; 766.5 nm; 285.2 nm; and 422.7 nm, using atomic absorption spectrometry methods. After the determination of the sodium, potassium, magnesium, and calcium minerals level followed by validation of analytical methods with accuracy, precision, linearity, range, limit of detection (LOD), and limit of quantitation (LOQ) parameters. Research results show a decrease in the sodium, potassium, magnesium, and calcium minerals level in boiled broccoli and cauliflower compared with fresh broccoli and cauliflower. Validation of analytical methods gives results that spectrometry methods used for determining sodium, potassium, magnesium, and calcium minerals level are valid. It concluded that the boiled gives the effect of decreasing the minerals level significantly in broccoli and cauliflower.

  17. Correlation between Wavelength Dispersive X-ray Fluorescence (WDXRF) analysis of hardened concrete for chlorides vs. Atomic Absorption (AA) analysis in accordance with AASHTO T- 260; sampling and testing for chloride ion in concrete and concrete raw mater

    DOT National Transportation Integrated Search

    2014-04-01

    A correlation between Wavelength Dispersive X-ray Fluorescence(WDXRF) analysis of Hardened : Concrete for Chlorides and Atomic Absorption (AA) analysis (current method AASHTO T-260, procedure B) has been : found and a new method of analysis has been ...

  18. [Determination of eight trace elements in the Swertia davidii Franch by flame atomic absorption spectrometry].

    PubMed

    Li, Tao; Wang, Yuan-zhong; Yu, Hon; Cao, Yu-juan; Zhang, Jing-jing; Liu, Qin

    2007-12-01

    The effects of different sample digestives on the determination of Swertia davidii Franch are compared. Eight trace elements in the Swertia davidii Franch were determined by flame atomic absorption spectrometry. The result shows that the RSD and recovery are better if the Swertia davidii Franch was digested with HNO3-HClO4 (5 : 1) mixed acid. The experimental results show that the detection limits were all smaller than 0.097 microg x mL(-1), the RSDs (n=8) all smaller than 2.34%, and the addition standard recovery (ASR) (n=8) was 89.32%-106.65% for all the elements.

  19. Determination of cadmium and lead at low levels by using preconcentration at fullerene coupled to thermospray flame furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Pereira, M. G.; Pereira-Filho, E. R.; Berndt, H.; Arruda, M. A. Z.

    2004-04-01

    A new and sensitive method for Cd and Pb determinations, based on the coupling of thermospray flame furnace atomic absorption spectrometry and a preconcentrator system, was developed. The procedure comprised the chelating of Cd and Pb with ammonium pyrrolidinedithiocarbamate with posterior adsorption of the chelates on a mixture (40 mg) of C 60 and C 70 at a flow rate of 2.0 ml min -1. These chelates were eluted from the adsorbent by passing a continuous flow of ethanol (80% v/v) at 0.9 ml min -1 to a nickel tube placed in an air/acetylene flame. After sample introduction into the tube by using a ceramic capillary (0.5 mm i.d.), the analytical signals were registered as peak height. Under these conditions, improvement factors in detectability of 675 and 200 were obtained for Cd and Pb, respectively, when compared to conventional flame atomic absorption spectrometry. Spiked samples (mineral and tap waters) and drinking water containing natural concentrations of Cd were employed for evaluating accuracy by comparing the results obtained from the proposed methodology with those using electrothermal atomic absorption spectrometry. In addition, certified reference materials (rye grass, CRM 281 and pig kidney, CRM 186) were also adopted for the accuracy tests. Due to the good linearity ranges for Cd (0.5-5.0 μg l -1) and Pb (10-250 μg l -1), samples with different concentrations could be analyzed. Detection limits of 0.1 and 2.4 μg l -1 were obtained for Cd and Pb, respectively, and RSD values <4.5% were observed ( n=10). Finally, a sample throughput of 24 determinations per hour was possible.

  20. Determination of gold in copper-bearing sulphide ores and metallurgical flotation products by atomic-absorption spectrometry.

    PubMed

    Strong, B; Murray-Smith, R

    1974-12-01

    A method is described which is specific for the determination of gold in sulphide copper ores and concentrates. Direct decomposition with aqua regia was found to be incomplete. A carefully controlled roasting stage followed by treatment with hydrochloric acid and then aqua regia was effective for dissolving all the gold. The gold is extracted into 4-methylpentan-2-one (methyli-sobutylketone) then aspirated into a very lean air-acetylene flame and the gold determined by atomic-absorption spectrometry. No interferences were observed from large concentrations of copper, iron or nickel.

  1. Characterization of amyloid in equine recurrent uveitis as AA amyloid.

    PubMed

    Ostevik, L; de Souza, G A; Wien, T N; Gunnes, G; Sørby, R

    2014-01-01

    Two horses with chronic uveitis and histological lesions consistent with equine recurrent uveitis (ERU) were examined. Microscopical findings in the ciliary body included deposits of amyloid lining the non-pigmented epithelium, intracytoplasmic, rod-shaped, eosinophilic inclusions and intraepithelial infiltration of T lymphocytes. Ultrastructural examination of the ciliary body of one horse confirmed the presence of abundant extracellular deposits of non-branching fibrils (9-11 nm in diameter) consistent with amyloid. Immunohistochemistry revealed strong positive labelling for AA amyloid and mass spectrometry showed the amyloid to consist primarily of serum amyloid A1 in both cases. The findings suggest that localized, intraocular AA amyloidosis may occur in horses with ERU. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of sulfite after on-line reduction of solid-phase manganese (IV) dioxide reactor.

    PubMed

    Zare-Dorabei, Rouholah; Boroun, Shokoufeh; Noroozifar, Meissam

    2018-02-01

    A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO 2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO 3 (pH 2) with flow rate of 3.5mLmin -1 at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry. The calibration curve was linear up to 25mgL -1 with a detection limit (DL) of 0.08mgL -1 for 400µL injection sample volume. The presented method is efficient toward sulfite determination in sugar and water samples with a relative standard deviation (RSD) less than 1.2% and a sampling rate of about 60h -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Determination of aluminium in groundwater samples by GF-AAS, ICP-AES, ICP-MS and modelling of inorganic aluminium complexes.

    PubMed

    Frankowski, Marcin; Zioła-Frankowska, Anetta; Kurzyca, Iwona; Novotný, Karel; Vaculovič, Tomas; Kanický, Viktor; Siepak, Marcin; Siepak, Jerzy

    2011-11-01

    The paper presents the results of aluminium determinations in ground water samples of the Miocene aquifer from the area of the city of Poznań (Poland). The determined aluminium content amounted from <0.0001 to 752.7 μg L(-1). The aluminium determinations were performed using three analytical techniques: graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The results of aluminium determinations in groundwater samples for particular analytical techniques were compared. The results were used to identify the ascent of ground water from the Mesozoic aquifer to the Miocene aquifer in the area of the fault graben. Using the Mineql+ program, the modelling of the occurrence of aluminium and the following aluminium complexes: hydroxy, with fluorides and sulphates was performed. The paper presents the results of aluminium determinations in ground water using different analytical techniques as well as the chemical modelling in the Mineql+ program, which was performed for the first time and which enabled the identification of aluminium complexes in the investigated samples. The study confirms the occurrence of aluminium hydroxy complexes and aluminium fluoride complexes in the analysed groundwater samples. Despite the dominance of sulphates and organic matter in the sample, major participation of the complexes with these ligands was not stated based on the modelling.

  4. Applicability of two mobile analysers for mercury in urine in small-scale gold mining areas.

    PubMed

    Baeuml, Jennifer; Bose-O'Reilly, Stephan; Lettmeier, Beate; Maydl, Alexandra; Messerer, Katalin; Roider, Gabriele; Drasch, Gustav; Siebert, Uwe

    2011-12-01

    Mercury is still used in developing countries to extract gold from the ore in small-scale gold mining areas. This is a major health hazard for people living in mining areas. The concentration of mercury in urine was analysed in different mining areas in Zimbabwe, Indonesia and Tanzania. First the urine samples were analysed by CV-AAS (cold vapour atomic absorption spectrometry) during the field projects with a mobile mercury analyser (Lumex(®) or Seefelder(®)) and secondly, in a laboratory with a stationary CV-AAS mercury analyser (PerkinElmer(®)). Caused by the different systems (reduction agent either SnCl(2) (Lumex(®) or Seefelder(®))) or NaBH(4) (PerkinElmer(®)), with the mobile analysers only the inorganic mercury was obtained and with the stationary system the total mercury concentration was measured. The aims of the study were whether the results obtained in field with the mobile equipments can be compared with the stationary reference method in the laboratory and allow the application of these mobile analysers in screening studies on concerned populations to select those, who are exposed to critical mercury levels. Overall, the concentrations obtained with the two mobile systems were approximately 25% lower than determined with the stationary system. Nevertheless, both mobile systems seem to be very useful for screening of volunteers in field. Moreover, regional staff may be trained on such analysers to perform screening tests by themselves. Copyright © 2011 Elsevier GmbH. All rights reserved.

  5. IJ-OpenCV: Combining ImageJ and OpenCV for processing images in biomedicine.

    PubMed

    Domínguez, César; Heras, Jónathan; Pascual, Vico

    2017-05-01

    The effective processing of biomedical images usually requires the interoperability of diverse software tools that have different aims but are complementary. The goal of this work is to develop a bridge to connect two of those tools: ImageJ, a program for image analysis in life sciences, and OpenCV, a computer vision and machine learning library. Based on a thorough analysis of ImageJ and OpenCV, we detected the features of these systems that could be enhanced, and developed a library to combine both tools, taking advantage of the strengths of each system. The library was implemented on top of the SciJava converter framework. We also provide a methodology to use this library. We have developed the publicly available library IJ-OpenCV that can be employed to create applications combining features from both ImageJ and OpenCV. From the perspective of ImageJ developers, they can use IJ-OpenCV to easily create plugins that use any functionality provided by the OpenCV library and explore different alternatives. From the perspective of OpenCV developers, this library provides a link to the ImageJ graphical user interface and all its features to handle regions of interest. The IJ-OpenCV library bridges the gap between ImageJ and OpenCV, allowing the connection and the cooperation of these two systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Chemical profile of pineapple cv. Vitória in different maturation stages using electrospray ionization mass spectrometry.

    PubMed

    Ogawa, Elizângela M; Costa, Helber B; Ventura, José A; Caetano, Luiz Cs; Pinto, Fernanda E; Oliveira, Bruno G; Barroso, Maria Eduarda S; Scherer, Rodrigo; Endringer, Denise C; Romão, Wanderson

    2018-02-01

    Pineapple is the fruit of Ananas comosus var. comosus plant, being cultivated in tropical areas and has high energy content and nutritional value. Herein, 30 samples of pineapple cv. Vitória were analyzed as a function of the maturation stage (0-5) and their physico-chemical parameters monitored. In addition, negative-ion mode electrospray ionization mass spectrometry [ESI(-)FT-ICR MS] was used to identify and semi-quantify primary and secondary metabolites present in the crude and phenolic extracts of pineapple, respectively. Physico-chemical tests show an increase in the total soluble solids (TSS) values and in the TSS/total titratable acidity ratio as a function of the maturity stage, where a maximum value was observed in stage 3 (¾ of the fruit is yellow, which corresponds to the color of the fruit peel). ESI(-)FT-ICR MS analysis for crude extracts showed the presence mainly of sugars as primary metabolites present in deprotonated molecule form ([M - H] - and [2 M - H] - ions) whereas, for phenolic fractions, 11 compounds were detected, being the most abundant in the third stage of maturation. This behavior was confirmed by quantitative analysis of total polyphenols. ESI-FT-ICR MS was efficient in identifying primary (carbohydrates and organic acids) and secondary metabolites (13 phenolic compounds) presents in the crude and phenolic extract of the samples, respectively. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. [Determination of trace gallium by graphite furnace atomic absorption spectrometry in urine].

    PubMed

    Zhou, L Z; Fu, S; Gao, S Q; He, G W

    2016-06-20

    To establish a method for determination trace gallium in urine by graphite furnace atomic absorption spectrometry (GFAAS). The ammonium dihydrogen phosphate was matrix modifier. The temperature effect about pyrolysis (Tpyr) and atomization temperature were optimized for determination of trace gallium. The method of technical standard about within-run, between-run and recoveries of standard were optimized. The method showed a linear relationship within the range of 0.20~80.00 μg/L (r=0.998). The within-run and between-run relative standard deviations (RSD) of repetitive measurement at 5.0, 10.0, 20.0 μg/L concentration levels were 2.1%~5.5% and 2.3%~3.0%. The detection limit was 0.06 μg/L. The recoveries of gallium were 98.2%~101.1%. This method is simple, low detection limit, accurate, reliable and reproducible. It has been applied for determination of trace gallium in urine samples those who need occupation health examination or poisoning diagnosis.

  8. Effect of the Microstructure on Diffusion Bonded AA5083, AA6082 and AA7075 Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Venugopal, S.; Mahendran, G.

    2018-05-01

    Rolled plates of aluminium alloys AA5083, AA6082 and AA7075 of 5 mm thickness are joined by diffusion bonding at varied parameters. The microstructure evolution of AA5083, AA6082 and AA7075 aluminium alloys is characterized by Transmission Electron Microscopy (TEM). Metallurgical investigations and mechanical tests are also performed to correlate the results of the TEM investigations with the mechanical properties of the produced diffusion bonded joints. It is observed that the bonding and shear strength of the alloys increase with the increase in bonding temperature, due to the diffusion of micro-constituents in the interface. High temperature enhances the uniform distribution of secondary phase particles and reduces pore formation/defects in the bonded joints.

  9. Lead concentrations and isotope ratios in street dust determined by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

    PubMed

    Nageotte, S M; Day, J P

    1998-01-01

    A major source of environmental lead, particularly in urban areas, has been from the combustion of leaded petrol. Street dust has previously been used to assess urban lead contamination, and the dust itself can also be a potential source of lead ingestion, particularly to children. The progressive reduction of lead in petrol, in recent years, would be expected to have been reflected in a reduction of lead in urban dust. We have tested this hypothesis by repeating an earlier survey of Manchester street dust and carrying out a comparable survey in Paris. Samples were collected from streets and parks, lead was extracted by digestion with concentrated nitric acid and determined by electrothermal atomic absorption spectrometry. Lead isotope ratios were measured by inductively coupled plasma mass spectrometry. Results for Manchester show that lead concentrations have fallen by about 40% (street dust averages, 941 micrograms g-1 (ppm) in 1975 down to 569 ppm in 1997). In Paris, the lead levels in street dust are much higher and significant differences were observed between types of street (not seen in Manchester). Additionally, lead levels in parks were much lower than in Manchester. Samples collected under the Eiffel Tower had very high concentrations and lead isotope ratios showed that this was unlikely to be fallout from motor vehicles but could be due to the paint used on the tower. Isotope ratios measurements also revealed that lead additives used in France and the UK come from different sources.

  10. Investigating effects of sample pretreatment on protein stability using size-exclusion chromatography and high-resolution continuum source atomic absorption spectrometry.

    PubMed

    Rakow, Tobias; El Deeb, Sami; Hahne, Thomas; El-Hady, Deia Abd; AlBishri, Hassan M; Wätzig, Hermann

    2014-09-01

    In this study, size-exclusion chromatography and high-resolution atomic absorption spectrometry methods have been developed and evaluated to test the stability of proteins during sample pretreatment. This especially includes different storage conditions but also adsorption before or even during the chromatographic process. For the development of the size exclusion method, a Biosep S3000 5 μm column was used for investigating a series of representative model proteins, namely bovine serum albumin, ovalbumin, monoclonal immunoglobulin G antibody, and myoglobin. Ambient temperature storage was found to be harmful to all model proteins, whereas short-term storage up to 14 days could be done in an ordinary refrigerator. Freezing the protein solutions was always complicated and had to be evaluated for each protein in the corresponding solvent. To keep the proteins in their native state a gentle freezing temperature should be chosen, hence liquid nitrogen should be avoided. Furthermore, a high-resolution continuum source atomic absorption spectrometry method was developed to observe the adsorption of proteins on container material and chromatographic columns. Adsorption to any container led to a sample loss and lowered the recovery rates. During the pretreatment and high-performance size-exclusion chromatography, adsorption caused sample losses of up to 33%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Determination of trace amount of cadmium using dispersive liquid-liquid microextraction-slotted quartz tube-flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Fırat, Merve; Bakırdere, Sezgin; Fındıkoğlu, Maral Selin; Kafa, Emine Betül; Yazıcı, Elif; Yolcu, Melda; Büyükpınar, Çağdaş; Chormey, Dotse Selali; Sel, Sabriye; Turak, Fatma

    2017-03-01

    This study was performed to develop a sensitive analytical method for the determination of cadmium by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after dispersive liquid-liquid microextraction (DLLME). The parameters affecting the cadmium complex formation and its extraction output were optimized to obtain high extraction efficiency. These included the pH and amount of the buffer solution, and the concentration of the ligand. The DLLME method was comprehensively optimized based on the type and amount of extraction solvent, dispersive solvent and salt. The type and period of mixing needed for a more effective extraction was also investigated. In order to further improve the sensitivity for the determination of cadmium, the flame atomic absorption spectrometry was fitted with a slotted quartz tube to increase the residence time of cadmium atoms in the pathway of incident light from a hollow cathode lamp. The limits of detection and quantitation (LOD and LOQ) for the FAAS were found to be 42 and 140 μg L- 1, respectively. Under the optimum conditions, LOD and LOQ of the FAAS after DLLME were calculated as 1.3 and 4.4 μg L- 1, respectively. Combining both optimized parameters of the DLLME and SQT-FAAS gave 0.5 and 1.5 μg L- 1 as LOD and LOQ, respectively. Accuracy of the method was also checked using a wastewater certified reference material (EU-L-2), and the result was in good agreement with the certified value.

  12. Ultrasensitive determination of cadmium in seawater by hollow fiber supported liquid membrane extraction coupled with graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Peng, Jin-feng; Liu, Rui; Liu, Jing-fu; He, Bin; Hu, Xia-lin; Jiang, Gui-bin

    2007-05-01

    A new procedure, based on hollow fiber supported liquid membrane preconcentration coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection, was developed for the determination of trace Cd in seawater samples. With 1-octanol that contained a mixture of dithizone (carrier) and oleic acid immobilized in the pores of the polypropylene hollow fiber as a liquid membrane, Cd was selectively extracted from water samples into 0.05 M HNO 3 that filled the lumen of the hollow fiber as a stripping solution. The main extraction related parameters were optimized, and the effects of salinity and some coexisting interferants were also evaluated. Under the optimum extraction conditions, an enrichment factor of 387 was obtained for a 100-mL sample solution. In combination with graphite furnace atomic absorption spectrometry, a very low detection limit (0.8 ng L - 1 ) and a relative standard deviation (2.5% at 50 ng L - 1 level) were achieved. Five seawater samples were analyzed by the proposed method without dilution, with detected Cd concentration in the range of 56.4-264.8 ng L - 1 and the relative spiked recoveries over 89%. For comparison, these samples were also analyzed by the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method after a 10-fold dilution for matrix effect elimination. Statistical analysis with a one-way ANOVA shows no significant differences (at 0.05 level) between the results obtained by the proposed and ICP-MS methods. Additionally, analysis of certified reference materials (GBW (E) 080040) shows good agreement with the certified value. These results indicate that this present method is very sensitive and reliable, and can effectively eliminate complex matrix interferences in seawater samples.

  13. Flameless Atomic Absorption Spectroscopy: Effects of Nitrates and Sulfates.

    DTIC Science & Technology

    1980-05-01

    ATTACHED DDJ~P 1413 EDITION 01 INO, 6 5 IabSoLEr J UjN!LbAa~ A- i SELU 0 IONOF I tG 651 J Flameless Atomic Absorption Spectroscopy: Effects of Nitrates...analytical techniques, flameless atomic absorption is subject to matrix or interference effects. Upon heating, nitrate and sulfate salts decompose to...Eklund and J.E. Smith, Anal Chem, 51, 1205 (1979) R.H. Eklund and J.A. Holcombe, Anal Chim. Acta, 109, 97 (1979) FLAMELESS ATOMIC ABSORPTION

  14. Piezoelectric-tuned microwave cavity for absorption spectrometry

    DOEpatents

    Leskovar, Branko; Buscher, Harold T.; Kolbe, William F.

    1978-01-01

    Gas samples are analyzed for pollutants in a microwave cavity that is provided with two highly polished walls. One wall of the cavity is mechanically driven with a piezoelectric transducer at a low frequency to tune the cavity over a band of microwave frequencies in synchronism with frequency modulated microwave energy applied to the cavity. Absorption of microwave energy over the tuned frequencies is detected, and energy absorption at a particular microwave frequency is an indication of a particular pollutant in the gas sample.

  15. Application of chitosan and its N-heterocyclic derivatives for preconcentration of noble metal ions and their determination using atomic absorption spectrometry.

    PubMed

    Azarova, Yu A; Pestov, A V; Ustinov, A Yu; Bratskaya, S Yu

    2015-12-10

    Chitosan and its N-heterocyclic derivatives N-2-(2-pyridyl)ethylchitosan (2-PEC), N-2-(4-pyridyl) ethylchitosan (4-PEC), and N-(5-methyl-4-imidazolyl) methylchitosan (IMC) have been applied in group preconcentration of gold, platinum, and palladium for subsequent determination by atomic absorption spectroscopy (AAS) in solutions with high background concentrations of iron and sodium ions. It has been shown that the sorption mechanism, which was elucidated by XPS, significantly influences the sorption capacity of materials, the efficiency of metal ions elution after preconcentration, and, as a result, the accuracy of metal determination by AAS. We have shown that native chitosan was not suitable for preconcentration of Au(III), if the elution step was used as a part of the analysis scheme. The group preconcentration of Au(III), Pd(II), and Pt(IV) with subsequent quantitative elution using 0.1M HCl/1M thiourea solution was possible only on IMC and 4-PEC. Application of IMC for analysis of the national standard quartz ore sample proved that gold could be accurately determined after preconcentration/elution with the recovery above 80%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Can sample treatments based on advanced oxidation processes assisted by high-intensity focused ultrasound be used for toxic arsenic determination in human urine by flow-injection hydride-generation atomic absorption spectrometry?

    PubMed

    Correia, A; Galesio, M; Santos, H; Rial-Otero, R; Lodeiro, C; Oehmen, A; Conceição, Antonio C L; Capelo, J L

    2007-05-15

    Two advanced oxidation processes (AOPs), based on high-intensity focused ultrasound (HIFU), namely, KMnO(4)/HCl/HIFU and H(2)O(2)/HCl/HIFU are studied and compared for the determination of toxic arsenic in human urine [As(III)+As(V)+MMA+DMA] by flow-injection hydride-generation atomic absorption spectrometry (FI-HG-AAS). The KMnO(4)/HCl/HIFU procedure was found to be adequate for organic matter degradation in human urine. l-cysteine (letra minuscula) was used for As reduction to the trivalent state. The new procedure was assessed with seven urines certified in different As species. Results revealed that with KMnO(4)/HCl/HIFU plus l-cysteine the toxic arsenic can be accurately measured in human urine whilst the H(2)O(2)/HCl/HIFU procedure underestimates toxic As. DMA and MMA degradation in urine were observed, due to the effects of the ultrasonic field. Recoveries for As(III), As(V), MMA and DMA were within the certified ranges. Arsenobetaine was not degraded by the AOPs. The new procedure adheres well to the principles of analytical minimalism: (i) low reagent consumption, (ii) low reagent concentration, (iii) low waste production and (iv) low amount of time required for sample preparation and analysis.

  17. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; preparation procedure for aquatic biological material determined for trace metals

    USGS Publications Warehouse

    Hoffman, Gerald L.

    1996-01-01

    A method for the chemical preparation of tissue samples that are subsequently analyzed for 22 trace metals is described. The tissue-preparation procedure was tested with three National Institute of Standards and Technology biological standard reference materials and two National Water Quality Laboratory homogenized biological materials. A low-temperature (85 degrees Celsius) nitric acid digestion followed by the careful addition of hydrogen peroxide (30-percent solution) is used to decompose the biological material. The solutions are evaporated to incipient dryness, reconstituted with 5 percent nitric acid, and filtered. After filtration the solutions were diluted to a known volume and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and cold vapor-atomic absorption spectrophotometry (CV-AAS). Many of the metals were determined by both ICP-MS and ICP-AES. This report does not provide a detailed description of the instrumental procedures and conditions used with the three types of instrumentation for the quantitation of trace metals determined in this study. Statistical data regarding recovery, accuracy, and precision for individual trace metals determined in the biological material tested are summarized.

  18. Laboratory study on the behaviour of spent AA household alkaline batteries in incineration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Almeida, Manuel F.; Xara, Susana M.; Delgado, Julanda

    2009-01-15

    The quantitative evaluation of emissions from incineration is essential when Life Cycle Assessment (LCA) studies consider this process as an end-of-life solution for some wastes. Thus, the objective of this work is to quantify the main gaseous emissions produced when spent AA alkaline batteries are incinerated. With this aim, batteries were kept for 1 h at 1273 K in a refractory steel tube hold in a horizontal electric furnace with temperature control. At one end of the refractory steel tube, a constant air flow input assures the presence of oxygen in the atmosphere and guides the gaseous emissions to amore » filter system followed by a set of two bubbler flasks having an aqueous solution of 10% (v/v) nitric acid. After each set of experiments, sulphur, chlorides and metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were analyzed in both the solutions obtained from the steel tube washing and from the bubblers. Sulphur, chlorides and metals were quantified, respectively, using barium sulfate gravimetry, the Volhard method and atomic absorption spectrometry (AAS). The emissions of zinc, the most emitted metal, represent about 6.5% of the zinc content in the batteries. Emissions of manganese (whose oxide is the main component of the cathode) and iron (from the cathode collector) are negligible when compared with their amount in AA alkaline batteries. Mercury is the metal with higher volatility in the composition of the batteries and was collected even in the second bubbler flask. The amount of chlorides collected corresponds to about 36% of the chlorine in the battery sleeve that is made from PVC. A considerable part of the HCl formed in PVC plastic sleeve incineration is neutralized with KOH, zinc and manganese oxides and, thus, it is not totally released in the gas. Some of the emissions are predictable through a thermodynamic data analysis at temperatures in the range of 1200-1300 K taking into account the composition of the batteries. This analysis

  19. On-line ion-exchange preconcentration and determination of traces of platinum by electrothermal atomic absorption spectrometry.

    PubMed

    González García, M M; Sánchez Rojas, F; Bosch Ojeda, C; García de Torres, A; Cano Pavón, J M

    2003-04-01

    A method to determine trace amounts of platinum in different samples based on electrothermal atomic absorption spectrometry is described. The preconcentration step is performed on a chelating resin microcolumn [1,5-bis(2-pyridyl)-3-sulfophenyl methylene thiocarbonohydrazide (PSTH) immobilized on an anion-exchange resin (Dowex 1x8-200)] placed in the autosampler arm. The combination of a peristaltic pump for sample loading and the atomic absorption spectrometer pumps for elution through a selection valve simplifies the hardware. The peristaltic pump and the selection valve are easily controlled electronically with two switches placed in the autosampler, which are activated when the autosampler arm is down. Thus, the process is fully automated without any modification of the software of the atomic absorption spectrometer. Under the optimum conditions with a 60-s preconcentration time, a sample flow rate of 2.4 mL min(-1), and an injection volume of eluent of 40 microL, a linear calibration graph was obtained in the range 0-100 ng mL(-1). The enrichment factor was 14. The detection limit under these conditions is 1 ng mL(-1), and the relative standard deviation (RSD) is 1.6% for 10 ng mL(-1) of Pt. The method has been applied to the determination of platinum in catalyst, vegetation, soil, and natural water samples. The results showed good agreement with the certified value and the recoveries of Pt added to samples were 98-105%.

  20. Percutaneous absorption of selenium sulfide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farley, J.; Skelly, E.M.; Weber, C.B.

    1986-01-01

    The purpose of this study was to determine selenium levels in the urine of Tinea patients before and after overnight application of a 2.5% selenium sulfide lotion. Selenium was measured by atomic absorption spectroscopy (AAS). Hydride generation and carbon rod atomization were studied. It was concluded from this study that selenium is absorbed through intact skin. Selenium is then excreted, at least partially, in urine, for at least a week following treatment. The data show that absorption and excretion of selenium vary on an individual basis. Selenium levels in urine following a single application of selenium sulfide lotion do notmore » indicate that toxic amounts of selenium are being absorbed. Repeated treatments with SeS/sub 2/ result in selenium concentrations in urine which are significantly higher than normal. Significant matrix effects are observed in the carbon rod atomization of urine samples for selenium determinations, even in the presence of a matrix modifier such as nickel. The method of standard additions is required to obtain accurate results in the direct determination of selenium in urine by carbon rod AAS.« less

  1. Determination of Aluminum in Dialysis Concentrates by Atomic Absorption Spectrometry after Coprecipitation with Lanthanum Phosphate.

    PubMed

    Selvi, Emine Kılıçkaya; Şahin, Uğur; Şahan, Serkan

    2017-01-01

    This method was developed for the determination of trace amounts of aluminum(III) in dialysis concentrates using atomic absorption spectrometry after coprecipitation with lanthanum phosphate. The analytical parameters that influenced the quantitative coprecipitation of analyte including amount of lanthanum, amount of phosfate, pH and duration time were optimized. The % recoveries of the analyte ion were in the range of 95-105 % with limit of detection (3s) of 0.5 µg l -1 . Preconcentration factor was found as 1000 and Relative Standard Deviation (RSD) % value obtained from model solutions was 2.5% for 0.02 mg L -1 . The accuracy of the method was evaluated with standard reference material (CWW-TMD Waste Water). The method was also applied to most concentrated acidic and basic dialysis concentrates with satisfactory results.

  2. The Use of a Microprocessor-Controlled, Video Output Atomic Absorption Spectrometer as an Educational Tool in a Two-Year Technical Curriculum.

    ERIC Educational Resources Information Center

    Kerfoot, Henry B.

    Based on instructional experiences at Charles County Community College, Maryland, this report examines the pedagogical advantage of teaching atomic absorption (AA) spectroscopy with an AA spectrophotometer that is equipped with a microprocessor and video output mechanism. The report first discusses the growing importance of AA spectroscopy in…

  3. Reduction of interferences in graphite furnace atomic absorption spectrometry by multiple linear regression modelling

    NASA Astrophysics Data System (ADS)

    Grotti, Marco; Abelmoschi, Maria Luisa; Soggia, Francesco; Tiberiade, Christian; Frache, Roberto

    2000-12-01

    The multivariate effects of Na, K, Mg and Ca as nitrates on the electrothermal atomisation of manganese, cadmium and iron were studied by multiple linear regression modelling. Since the models proved to efficiently predict the effects of the considered matrix elements in a wide range of concentrations, they were applied to correct the interferences occurring in the determination of trace elements in seawater after pre-concentration of the analytes. In order to obtain a statistically significant number of samples, a large volume of the certified seawater reference materials CASS-3 and NASS-3 was treated with Chelex-100 resin; then, the chelating resin was separated from the solution, divided into several sub-samples, each of them was eluted with nitric acid and analysed by electrothermal atomic absorption spectrometry (for trace element determinations) and inductively coupled plasma optical emission spectrometry (for matrix element determinations). To minimise any other systematic error besides that due to matrix effects, accuracy of the pre-concentration step and contamination levels of the procedure were checked by inductively coupled plasma mass spectrometric measurements. Analytical results obtained by applying the multiple linear regression models were compared with those obtained with other calibration methods, such as external calibration using acid-based standards, external calibration using matrix-matched standards and the analyte addition technique. Empirical models proved to efficiently reduce interferences occurring in the analysis of real samples, allowing an improvement of accuracy better than for other calibration methods.

  4. Optimization of electrothermal atomization parameters for simultaneous multielement atomic absorption spectrometry

    USGS Publications Warehouse

    Harnly, J.M.; Kane, J.S.

    1984-01-01

    The effect of the acid matrix, the measurement mode (height or area), the atomizer surface (unpyrolyzed and pyrolyzed graphite), the atomization mode (from the wall or from a platform), and the atomization temperature on the simultaneous electrothermal atomization of Co, Cr, Cu, Fe, Mn, Mo, Ni, V, and Zn was examined. The 5% HNO3 matrix gave rise to severe irreproducibility using a pyrolyzed tube unless the tube was properly "prepared". The 5% HCl matrix did not exhibit this problem, and no problems were observed with either matrix using an unpyrolized tube or a pyrolyzed platform. The 5% HCl matrix gave better sensitivities with a pyrolyzed tube but the two matrices were comparable for atomization from a platform. If Mo and V are to be analyzed with the other seven elements, a high atomization temperature (2700??C or greater) is necessary regardless of the matrix, the measurement mode, the atomization mode, or the atomizer surface. Simultaneous detection limits (peak height with pyrolyzed tube atomization) were comparable to those of conventional atomic absorption spectrometry using electrothermal atomization above 280 nm. Accuracies and precisions of ??10-15% were found in the 10 to 120 ng mL-1 range for the analysis of NBS acidified water standards.

  5. Temperature dependence of the Urbach optical absorption edge: A theory of multiple phonon absorption and emission sidebands

    NASA Astrophysics Data System (ADS)

    Grein, C. H.; John, Sajeev

    1989-01-01

    The optical absorption coefficient for subgap electronic transitions in crystalline and disordered semiconductors is calculated by first-principles means with use of a variational principle based on the Feynman path-integral representation of the transition amplitude. This incorporates the synergetic interplay of static disorder and the nonadiabatic quantum dynamics of the coupled electron-phonon system. Over photon-energy ranges of experimental interest, this method predicts accurate linear exponential Urbach behavior of the absorption coefficient. At finite temperatures the nonlinear electron-phonon interaction gives rise to multiple phonon emission and absorption sidebands which accompany the optically induced electronic transition. These sidebands dominate the absorption in the Urbach regime and account for the temperature dependence of the Urbach slope and energy gap. The physical picture which emerges is that the phonons absorbed from the heat bath are then reemitted into a dynamical polaronlike potential well which localizes the electron. At zero temperature we recover the usual polaron theory. At high temperatures the calculated tail is qualitatively similar to that of a static Gaussian random potential. This leads to a linear relationship between the Urbach slope and the downshift of the extrapolated continuum band edge as well as a temperature-independent Urbach focus. At very low temperatures, deviations from these rules are predicted arising from the true quantum dynamics of the lattice. Excellent agreement is found with experimental data on c-Si, a-Si:H, a-As2Se3, and a-As2S3. Results are compared with a simple physical argument based on the most-probable-potential-well method.

  6. Determination of total mercury in environmental and biological samples by flow injection cold vapour atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Murphy, James; Jones, Phil; Hill, Steve J.

    1996-12-01

    A simple and accurate method has been developed for the determination of total mercury in environmental and biological samples. The method utilises an off-line microwave digestion stage followed by analysis using a flow injection system with detection by cold vapour atomic absorption spectrometry. The method has been validated using two certified reference materials (DORM-1 dogfish and MESS-2 estuarine sediment) and the results agreed well with the certified values. A detection limit of 0.2 ng g -1 Hg was obtained and no significant interference was observed. The method was finally applied to the determination of mercury in river sediments and canned tuna fish, and gave results in the range 0.1-3.0 mg kg -1.

  7. Use of electrothermal atomic absorption spectrometry for size profiling of gold and silver nanoparticles.

    PubMed

    Panyabut, Teerawat; Sirirat, Natnicha; Siripinyanond, Atitaya

    2018-02-13

    Electrothermal atomic absorption spectrometry (ETAAS) was applied to investigate the atomization behaviors of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) in order to relate with particle size information. At various atomization temperatures from 1400 °C to 2200 °C, the time-dependent atomic absorption peak profiles of AuNPs and AgNPs with varying sizes from 5 nm to 100 nm were examined. With increasing particle size, the maximum absorbance was observed at the longer time. The time at maximum absorbance was found to linearly increase with increasing particle size, suggesting that ETAAS can be applied to provide the size information of nanoparticles. With the atomization temperature of 1600 °C, the mixtures of nanoparticles containing two particle sizes, i.e., 5 nm tannic stabilized AuNPs with 60, 80, 100 nm citrate stabilized AuNPs, were investigated and bimodal peaks were observed. The particle size dependent atomization behaviors of nanoparticles show potential application of ETAAS for providing size information of nanoparticles. The calibration plot between the time at maximum absorbance and the particle size was applied to estimate the particle size of in-house synthesized AuNPs and AgNPs and the results obtained were in good agreement with those from flow field-flow fractionation (FlFFF) and transmission electron microscopy (TEM) techniques. Furthermore, the linear relationship between the activation energy and the particle size was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Pigment identification in artwork using graphite furnace atomic absorption spectrometry.

    PubMed

    Goltz, D M; Coombs, J; Marion, C; Cloutis, E; Gibson, J; Attas, M; Choo-Smith, L-P; Collins, C

    2004-06-17

    The use of a sampling technique is described for the identification of metals from inorganic pigments in paint. The sampling technique involves gently contacting a cotton swab with the painted surface to physically remove a minute quantity ( approximately 1-2mug) of pigment. The amount of material removed from the painted surface is invisible to the unaided eye and does not cause any visible effect to the painted surface. The cotton swab was then placed in a 1.5ml polystyrene beaker containing HNO(3) to extract pigment metals prior to analysis using graphite furnace atomic absorption spectrometry (GFAAS). GFAAS is well suited for identifying pigment metals since it requires small samples and many pigments consist of main group elements (e.g. Al) as well as transition metals (e.g. Zn, Fe and Cd). Using Cd (cadmium red) as the test element, the reproducibility of sampling a paint surface with the cotton swab was approximately 13% in either a water or oil medium. To test the feasibility of cotton sampling for pigment identification, samples were obtained from paintings (watercolour and oil) of a local collection. Raman spectra provided complementary information to the GFAAS, which together are essential for positive identification of some pigments. For example, GFAAS indicated the presence of Cu, but the Raman spectra positively identified the modern copper pigment phthalocyanine green (Cu(C(32)Cl(16)N(8)). Both Raman spectroscopy and GFAAS were useful for identifying ZnO as a white pigment.

  9. Pre-analytic evaluation of volumetric absorptive microsampling and integration in a mass spectrometry-based metabolomics workflow.

    PubMed

    Volani, Chiara; Caprioli, Giulia; Calderisi, Giovanni; Sigurdsson, Baldur B; Rainer, Johannes; Gentilini, Ivo; Hicks, Andrew A; Pramstaller, Peter P; Weiss, Guenter; Smarason, Sigurdur V; Paglia, Giuseppe

    2017-10-01

    Volumetric absorptive microsampling (VAMS) is a novel approach that allows single-drop (10 μL) blood collection. Integration of VAMS with mass spectrometry (MS)-based untargeted metabolomics is an attractive solution for both human and animal studies. However, to boost the use of VAMS in metabolomics, key pre-analytical questions need to be addressed. Therefore, in this work, we integrated VAMS in a MS-based untargeted metabolomics workflow and investigated pre-analytical strategies such as sample extraction procedures and metabolome stability at different storage conditions. We first evaluated the best extraction procedure for the polar metabolome and found that the highest number and amount of metabolites were recovered upon extraction with acetonitrile/water (70:30). In contrast, basic conditions (pH 9) resulted in divergent metabolite profiles mainly resulting from the extraction of intracellular metabolites originating from red blood cells. In addition, the prolonged storage of blood samples at room temperature caused significant changes in metabolome composition, but once the VAMS devices were stored at - 80 °C, the metabolome remained stable for up to 6 months. The time used for drying the sample did also affect the metabolome. In fact, some metabolites were rapidly degraded or accumulated in the sample during the first 48 h at room temperature, indicating that a longer drying step will significantly change the concentration in the sample. Graphical abstract Volumetric absorptive microsampling (VAMS) is a novel technology that allows single-drop blood collection and, in combination with mass spectrometry (MS)-based untargeted metabolomics, represents an attractive solution for both human and animal studies. In this work, we integrated VAMS in a MS-based untargeted metabolomics workflow and investigated pre-analytical strategies such as sample extraction procedures and metabolome stability at different storage conditions. The latter revealed that

  10. Rapid separation on copper powder of total mercury in blood and determination of mercury by flameless atomic absorption spectrometry.

    PubMed

    Dogan, S; Haerdi, W

    1979-01-01

    The determination of mercury in blood by flameless atomic absorption spectrometry (FAAS) has been described. Prior to its analysis, the sample was decomposed by combustion and separated on a copper powder micro-column. A special type of cell has been used which gives a better sensitivity compared with the types of cells described in the literature and the method of FAAS analysis has been improved. The sensitivity of 0.1 ng for 1% absorbance was observed and the standard deviation for six determinations at this level was found to be +/- 0.05 ng, for 95% probability.

  11. Simple method for determination of selenium in biological materials by flameless atomic-absorption spectrometry using a carbon-tube atomizer.

    PubMed

    Ishizaki, M

    1978-03-01

    A method for determination of selenium in biological materials by flameless atomic-absorption spectrometry using a carbon-tube atomizer is described. The sample is burned by an oxygen-flask combustion procedure, the resulting solution is treated with a cation-exchange resin to eliminate interfering cations, the selenium is extracted with dithizone in carbon tetrachloride and the resulting selenium dithizonate is combined with nickel nitrate in the carbon tube to enhance the sensitivity for selenium and avoid volatilization losses. The method measures selenium concentrations as low as 0.01 mug/g with a relative standard deviation of 8%.

  12. Aa Ah Nak

    ERIC Educational Resources Information Center

    Tha, Na Gya; Wus, Thay

    2017-01-01

    In this article, Aa Ah Nak, the authors' methodology presents not only various reflections but also diverse contradictions about the Aa Nii language as well as language revitalization. This article explores language foundation and how the Aa Nii language revitalization is inextricably linked to the genocide and resulting historic trauma pervasive…

  13. Direct determination of chromium in infant formulas employing high-resolution continuum source electrothermal atomic absorption spectrometry and solid sample analysis.

    PubMed

    Silva, Arlene S; Brandao, Geovani C; Matos, Geraldo D; Ferreira, Sergio L C

    2015-11-01

    The present work proposed an analytical method for the direct determination of chromium in infant formulas employing the high-resolution continuum source electrothermal atomic absorption spectrometry combined with the solid sample analysis (SS-HR-CS ET AAS). Sample masses up to 2.0mg were directly weighted on a solid sampling platform and introduced into the graphite tube. In order to minimize the formation of carbonaceous residues and to improve the contact of the modifier solution with the solid sample, a volume of 10 µL of a solution containing 6% (v/v) H2O2, 20% (v/v) ethanol and 1% (v/v) HNO3 was added. The pyrolysis and atomization temperatures established were 1600 and 2400 °C, respectively, using magnesium as chemical modifier. The calibration technique was evaluated by comparing the slopes of calibration curves established using aqueous and solid standards. This test revealed that chromium can be determined employing the external calibration technique using aqueous standards. Under these conditions, the method developed allows the direct determination of chromium with limit of quantification of 11.5 ng g(-1), precision expressed as relative standard deviation (RSD) in the range of 4.0-17.9% (n=3) and a characteristic mass of 1.2 pg of chromium. The accuracy was confirmed by analysis of a certified reference material of tomato leaves furnished by National Institute of Standards and Technology. The method proposed was applied for the determination of chromium in five different infant formula samples. The chromium content found varied in the range of 33.9-58.1 ng g(-1) (n=3). These samples were also analyzed employing ICP-MS. A statistical test demonstrated that there is no significant difference between the results found by two methods. The chromium concentrations achieved are lower than the maximum limit permissible for chromium in foods by Brazilian Legislation. Copyright © 2015. Published by Elsevier B.V.

  14. Multicomutation flow system for manganese speciation by solid phase extraction and flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Tobiasz, Anna; Sołtys, Monika; Kurys, Ewa; Domagała, Karolina; Dudek-Adamska, Danuta; Walas, Stanisław

    2017-08-01

    In the paper an application of solid phase extraction technique for speciation analysis of manganese in water samples with the use of flame atomic absorption spectrometry is presented. Two types of sorbents, activated silica gel and Dowex 1 × 4, were used respectively for simultaneously Mn2 + and MnO42 - retention and preconcentration. The whole procedure was realized in multicomutation flow system. Different conditions like: type and concentration of eluent, sample pH and loading time were tested during the study. Under appropriate conditions, it was possible to obtained enrichment factors of 20 and 16 for Mn(II) and Mn(VII), respectively. Precision of the procedure was close to 4% (measured as relative standard deviation), whereas the detection limit (3σ) was 1.4 μg·L- 1 for Mn(II) and 4.8 μg·L- 1 for Mn(VII).

  15. Determination of Pd, Pt and Rh in vehicles escape fumes by GF-AAS and ICP-OES.

    PubMed

    Goncalves, Antonio; Domínguez, José R; Alvarado, José

    2008-04-15

    Automotive exhaust gases from vehicles using catalytic converters were filtered through cellulose filter papers to collect suspended particles expulsed along with the engine's escape fumes. A specially designed sample collector was used for supporting the filter papers during collection. The collector was manufactured from a new car's exhaust pipe. A cellulose circular paper filter, 11 cm diameter, was attached to one end of the pipe and kept centered by pressing it against the borders of the pipe by means of a perforated aluminum cap, slightly wider than the pipe, used to cover this end of the collector. Filter papers loaded with the solid particles were acid-digested using a modified domestic microwave oven to bring the solid material into solution. The resulting solutions were analyzed for Pt by graphite furnace atomic absorption spectrometry (GF-AAS) and for Pd and Rh by inductively coupled plasma (ICP-OES). Results indicate that concentration of these analytes in the particulate is higher for new vehicles, having new catalytic converters, than for old ones. Maximum Pd, Pt and Rh in the samples analyzed were found to be 5.36, 12.60 and 1.03 microg g(-1), respectively.

  16. CV 100--Still Going Strong

    ERIC Educational Resources Information Center

    Abrahams, A. L.

    1976-01-01

    Describes results of a study that used CV 100, a fuel additive for use in oil-fired heating systems, on a trial basis in 12 Ontario schools. The test showed an average 12 percent reduction in fuel costs in the schools using CV 100. (JG)

  17. Determination of sulfur in food by high resolution continuum source flame molecular absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Zambrzycka, Elżbieta; Godlewska-Żyłkiewicz, Beata

    2014-11-01

    In the present work, a fast, simple and sensitive analytical method for determination of sulfur in food and beverages by high resolution continuum source flame molecular absorption spectrometry was developed. The determination was performed via molecular absorption of carbon monosulfide, CS. Different CS rotational lines (257.959 nm, 258.033 nm, 258.055 nm), number of pixels and types of standard solution of sulfur, namely: sulfuric acid, sodium sulfate, ammonium sulfate, sodium sulfite, sodium sulfide, DL-cysteine, and L-cystine, were studied in terms of sensitivity, repeatability of results as well as limit of detection and limit of quantification. The best results were obtained for measurements of absorption of the CS molecule at 258.055 nm at the wavelength range covering 3 pixels and DL-cysteine in 0.2 mol L- 1 HNO3 solution as a calibration standard. Under optimized conditions the limit of detection and the limit of quantification achieved for sulfur were 10.9 mg L- 1 and 36.4 mg L- 1, respectively. The repeatability of the results expressed as relative standard deviation was typically < 5%. The accuracy of the method was tested by analysis of digested biological certified reference materials (soya bean flour, corn flour and herbs) and recovery experiment for beverage samples with added known amount of sulfur standard. The recovery of analyte from such samples was in the range of 93-105% with the repeatability in the range of 4.1-5.0%. The developed method was applied for the determination of sulfur in milk (194 ± 10 mg kg- 1), egg white (2188 ± 29 mg kg- 1), mineral water (31.0 ± 0.9 mg L- 1), white wine (260 ± 4 mg L- 1) and red wine (82 ± 2 mg L- 1), as well as in sample rich in ions, such as bitter mineral water (6900 ± 100 mg L- 1).

  18. A method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry.

    PubMed

    Parkinson, I S; Ward, M K; Kerr, D N

    1982-10-27

    A simple but reliable method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry is described. No preparatory procedures are required for water samples, although serum is mixed with a wetting agent (Triton X-100) to allow complete combustion of the samples and to improve analytical precision. Precautions to prevent contamination during sample handling are discussed and instrumental parameters are defined. The method has a sensitivity of 35.5 pg and detection limits of 2.3 micrograms Al/l for serum and 1.3 micrograms Al/l for water. The method was used to determine the aluminium concentration in serum of 46 normal subjects. The mean aluminium content was 7.3 micrograms/l (range 2--15 micrograms/l.

  19. Ion Imprinted Polymer for Preconcentration and Determination of Ultra-Trace Cadmium, Employing Flow Injection Analysis with Thermo Spray Flame Furnace Atomic Absorption Spectrometry.

    PubMed

    do Lago, Ayla Campos; Marchioni, Camila; Mendes, Tássia Venga; Wisniewski, Célio; Fadini, Pedro Sergio; Luccas, Pedro Orival

    2016-11-01

    This work proposes a preconcentration method using an ion imprinted polymer (IIP) for determination of cadmium, in several samples, employing a mini-column filled with the polymer coupled into a flow injection analysis system with detection by thermospray flame furnace atomic absorption spectrometry (FIA-TS-FF-AAS). The polymer was synthesized via bulk using methacrylic acid and vinylimidazole as a functional monomer. For the FIA system initial assessment, the variables: pH, eluent concentration and buffer concentration were studied, employing a 23 full factorial design. To obtain the optimum values for each significant variable, a Doehlert matrix was employed. After the optimization conditions as: pH 5.8, eluent (HNO3) concentration of 0.48 mol L -1 and buffer concentration of 0.01 mol L -1 , were adopted. The proposed method showed a linear response in the range of 0.081-10.0 μg L -1 , limits detection and quantification of 0.024 and 0.081 μg L -1 , respectively; preconcentration factor of 165, consumptive index of 0.06 mL, concentration efficiency 132 min -1 , and frequency of readings equal to 26 readings h -1 The accuracy was checked by analysis of certified reference materials for trace metals and recovery tests. The obtained results were in agreement with 95% confidence level (t-test). The method was adequate to apply in samples of: jewelry (earrings) (2.38 ± 0.28 μg kg -1 ), black tea (1.09 ± 0.15 μg kg -1 ), green tea (3.85 ± 0.13 μg kg -1 ), cigarette tobacco (38.27 ± 0.22 μg kg -1 ), and hair (0.35 ± 0.02 μg kg -1 ). © The Author(s) 2016.

  20. Selective and sensitive speciation analysis of Cr(VI) and Cr(III), at sub-μgL-1 levels in water samples by electrothermal atomic absorption spectrometry after electromembrane extraction.

    PubMed

    Tahmasebi, Zeinab; Davarani, Saied Saeed Hosseiny

    2016-12-01

    In this work, electromembrane extraction in combination with electrothermal atomic absorption spectrometry (ET-AAS) was investigated for speciation, preconcentration and quantification of Cr(VI) and Cr(III) in water samples through the selective complexation of Cr(VI) with 1,5-diphenylcarbazide (DPC) as a complexing agent. DPC reduces Cr(VI) to Cr(III) ions and then Cr(III) species are extracted based on electrokinetic migration of their cationic complex (Cr(III)-DPC) toward the negative electrode placed in the hollow fiber. Also, once oxidized to Cr(VI), Cr(III) ions in initial sample were determined by this procedure. The influence of extraction parameters such as pH, type of organic solvent, chelating agent concentration, stirring rate, extraction time and applied voltage were evaluated following a one-at-a-time optimization approach. Under optimized conditions, the extracted analyte was quantified by ETAAS, with an acceptable linearity in the range of 0.05-5ngmL -1 (R 2 value=0.996), and a repeatability (%RSD) between 3.7% and 12.2% (n=4) for 5.0 and 1.0ngmL -1 of Cr(VI), respectively. Also, we obtained an enrichment factor of 110 that corresponded to the recovery of 66%. The detection limit (S/N ratio of 3:1) was 0.02ngmL -1 . Finally, this new method was successfully employed to determine Cr(III) and Cr(VI) species in real water samples. Copyright © 2016. Published by Elsevier B.V.

  1. Comparison of liquid chromatography-isotope ratio mass spectrometry (LC/IRMS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) for the determination of collagen amino acid δ13C values for palaeodietary and palaeoecological reconstruction.

    PubMed

    Dunn, Philip J H; Honch, Noah V; Evershed, Richard P

    2011-10-30

    Results are presented of a comparison of the amino acid (AA) δ(13)C values obtained by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) and liquid chromatography-isotope ratio mass spectrometry (LC/IRMS). Although the primary focus was the compound-specific stable carbon isotope analysis of bone collagen AAs, because of its growing application for palaeodietary and palaeoecological reconstruction, the results are relevant to any field where AA δ(13)C values are required. We compare LC/IRMS with the most up-to-date GC/C/IRMS method using N-acetyl methyl ester (NACME) AA derivatives. This comparison involves the analysis of standard AAs and hydrolysates of archaeological human bone collagen, which have been previously investigated as N-trifluoroacetyl isopropyl esters (TFA/IP). It was observed that, although GC/C/IRMS analyses required less sample, LC/IRMS permitted the analysis of a wider range of AAs, particularly those not amenable to GC analysis (e.g. arginine). Accordingly, reconstructed bulk δ(13)C values based on LC/IRMS-derived δ(13)C values were closer to the EA/IRMS-derived δ(13)C values than those based on GC/C/IRMS values. The analytical errors for LC/IRMS AA δ(13)C values were lower than GC/C/IRMS determinations. Inconsistencies in the δ(13)C values of the TFA/IP derivatives compared with the NACME- and LC/IRMS-derived δ(13)C values suggest inherent problems with the use of TFA/IP derivatives, resulting from: (i) inefficient sample combustion, and/or (ii) differences in the intra-molecular distribution of δ(13)C values between AAs, which are manifested by incomplete combustion. Close similarities between the NACME AA δ(13)C values and the LC/IRMS-derived δ(13)C values suggest that the TFA/IP derivatives should be abandoned for the natural abundance determinations of AA δ(13)C values. Copyright © 2011 John Wiley & Sons, Ltd.

  2. Cu determination in crude oil distillation products by atomic absorption and inductively coupled plasma mass spectrometry after analyte transfer to aqueous solution

    NASA Astrophysics Data System (ADS)

    Kowalewska, Zofia; Ruszczyńska, Anna; Bulska, Ewa

    2005-03-01

    Cu was determined in a wide range of petroleum products from crude oil distillation using flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different procedures of sample preparation were evaluated: (i) mineralization with sulfuric acid in an open system, (ii) mineralization in a closed microwave system, (iii) combustion in hydrogen-oxygen flame in the Wickbold's apparatus, (iv) matrix evaporation followed by acid dissolution, and (v) acidic extraction. All the above procedures led to the transfer of the analyte into an aqueous solution for the analytical measurement step. It was found that application of FAAS was limited to the analysis of the heaviest petroleum products of high Cu content. In ICP-MS, the use of internal reference method (with Rh or In as internal reference element) was required to eliminate the matrix effects in the analysis of extracts and the concentrated solutions of mineralized heavy petroleum products. The detection limits (in original samples) were equal to, respectively, 10, 86, 3.3, 0.9 and 0.4 ng g - 1 in procedures i-v with ETAAS detection and 10, 78, 1.1 and 0.5 ng g - 1 in procedures i-iii and v with ICP-MS detection. The procedures recommended here were validated by recovery experiments, certified reference materials analysis and comparison of results, obtained for a given sample, in different ways. The Cu content in the analyzed samples was: 50-110 ng g - 1 in crude oil, < 0.4-6 ng g - 1 in gasoline, < 0.5-2 ng g - 1 in atmospheric oil, < 6-100 ng g - 1 in heavy vacuum oil and 140-300 ng g - 1 in distillation residue.

  3. Estimate of the uncertainty in measurement for the determination of mercury in seafood by TDA AAS.

    PubMed

    Torres, Daiane Placido; Olivares, Igor R B; Queiroz, Helena Müller

    2015-01-01

    An approach for the estimate of the uncertainty in measurement considering the individual sources related to the different steps of the method under evaluation as well as the uncertainties estimated from the validation data for the determination of mercury in seafood by using thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) is proposed. The considered method has been fully optimized and validated in an official laboratory of the Ministry of Agriculture, Livestock and Food Supply of Brazil, in order to comply with national and international food regulations and quality assurance. The referred method has been accredited under the ISO/IEC 17025 norm since 2010. The approach of the present work in order to reach the aim of estimating of the uncertainty in measurement was based on six sources of uncertainty for mercury determination in seafood by TDA AAS, following the validation process, which were: Linear least square regression, Repeatability, Intermediate precision, Correction factor of the analytical curve, Sample mass, and Standard reference solution. Those that most influenced the uncertainty in measurement were sample weight, repeatability, intermediate precision and calibration curve. The obtained result for the estimate of uncertainty in measurement in the present work reached a value of 13.39%, which complies with the European Regulation EC 836/2011. This figure represents a very realistic estimate of the routine conditions, since it fairly encompasses the dispersion obtained from the value attributed to the sample and the value measured by the laboratory analysts. From this outcome, it is possible to infer that the validation data (based on calibration curve, recovery and precision), together with the variation on sample mass, can offer a proper estimate of uncertainty in measurement.

  4. Application of Plackett-Burman and Doehlert designs for optimization of selenium analysis in plasma with electrothermal atomic absorption spectrometry.

    PubMed

    El Ati-Hellal, Myriam; Hellal, Fayçal; Hedhili, Abderrazek

    2014-10-01

    The aim of this study was the optimization of selenium determination in plasma samples with electrothermal atomic absorption spectrometry using experimental design methodology. 11 variables being able to influence selenium analysis in human blood plasma by electrothermal atomic absorption spectrometry (ETAAS) were evaluated with Plackett-Burman experimental design. These factors were selected from sample preparation, furnace program and chemical modification steps. Both absorbance and background signals were chosen as responses in the screening approach. Doehlert design was used for method optimization. Results showed that only ashing temperature has a statistically significant effect on the selected responses. Optimization with Doehlert design allowed the development of a reliable method for selenium analysis with ETAAS. Samples were diluted 1/10 with 0.05% (v/v) TritonX-100+2.5% (v/v) HNO3 solution. Optimized ashing and atomization temperatures for nickel modifier were 1070°C and 2270°C, respectively. A detection limit of 2.1μgL(-1) Se was obtained. Accuracy of the method was checked by the analysis of selenium in Seronorm™ Trace element quality control serum level 1. The developed procedure was applied for the analysis of total selenium in fifteen plasma samples with standard addition method. Concentrations ranged between 24.4 and 64.6μgL(-1), with a mean of 42.6±4.9μgL(-1). The use of experimental designs allowed the development of a cheap and accurate method for selenium analysis in plasma that could be applied routinely in clinical laboratories. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  5. A new supramolecular based liquid solid microextraction method for preconcentration and determination of trace bismuth in human blood serum and hair samples by electrothermal atomic absorption spectrometry.

    PubMed

    Kahe, Hadi; Chamsaz, Mahmoud

    2016-11-01

    A simple and reliable supramolecule-aggregated liquid solid microextraction method is described for preconcentration and determination of trace amounts of bismuth in water as well as human blood serum and hair samples. Catanionic microstructures of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactants, dissolved in deionized water/propanol, are used as a green solvent to extract bismuth (III)-diethyldithiocarbamate complexes by dispersive microextraction methodology. The extracted solid phase is easily removed and dissolved in 50 μL propanol for subsequent measurement by electrothermal atomic absorption spectrometry (ET-AAS). The procedure benefits the merits of supramolecule aggregates' properties and dispersive microextraction technique using water as the main component of disperser solvent, leading to direct interaction with analyte. Phase separation behavior of extraction solvent and different parameters influencing the extraction efficiency of bismuth ion such as salt concentration, pH, centrifugation time, amount of chelating agent, SDS:CTAB mole ratio, and solvent amounts were thoroughly optimized. Under the optimal experimental conditions, the calibration curve was linear in the range of 0.3-6 μg L -1 Bi (III) with a limit of detection (LOD) of 0.16 μg L -1 (S/N = 3). The relative standard deviations (RSD) of determination were obtained to be 5.1 and 6.2 % for 1 and 3 μg L -1 of Bi (III), respectively. The developed method was successfully applied as a sensitive and accurate technique for determination of bismuth ion in human blood serum, hair samples, and a certified reference material.

  6. Evaluation of zirconium as a permanent chemical modifier using synchrotron radiation and imaging techniques for lithium determination in sediment slurry samples by ET AAS.

    PubMed

    Flores, Araceli V; Pérez, Carlos A; Arruda, Marco A Z

    2004-02-27

    In the present paper, lithium was determined in river sediment using slurry sampling and electrothermal atomic absorption spectrometry (ET AAS) after L'vov platform coating with zirconium (as a permanent chemical modifier). The performance of this modifier and its distribution on the L'vov platform after different heating cycles were evaluated using synchrotron radiation X-ray fluorescence (SRXRF) and imaging scanning electron microscopy (SEM) techniques. The analytical conditions for lithium determination in river sediment slurries were also investigated and the best conditions were obtained employing 1300 and 2300 degrees C for pyrolysis and atomization temperatures, respectively. In addition, 100mg of sediment samples were prepared using 4.0moll(-1) HNO(3). The Zr-coating permitted lithium determination with good precision and accuracy after 480 heating cycles using the same platform for slurry samples. The sediment samples were collected from five different points of the Cachoeira river, São Paulo, Brazil. The detection and quantification limits were, respectively, 0.07 and 0.23mugl(-1).

  7. Determination of mercury distribution inside spent compact fluorescent lamps by atomic absorption spectrometry.

    PubMed

    Rey-Raap, Natalia; Gallardo, Antonio

    2012-05-01

    In this study, spent compact fluorescent lamps were characterized to determine the distribution of mercury. The procedure used in this research allowed mercury to be extracted in the vapor phase, from the phosphor powder, and the glass matrix. Mercury concentration in the three phases was determined by the method known as cold vapor atomic absorption spectrometry. Median values obtained in the study showed that a compact fluorescent lamp contained 24.52±0.4ppb of mercury in the vapor phase, 204.16±8.9ppb of mercury in the phosphor powder, and 18.74±0.5ppb of mercury in the glass matrix. There are differences in mercury concentration between the lamps since the year of manufacture or the hours of operation affect both mercury content and its distribution. The 85.76% of the mercury introduced into a compact fluorescent lamp becomes a component of the phosphor powder, while more than 13.66% is diffused through the glass matrix. By washing and eliminating all phosphor powder attached to the glass surface it is possible to classified the glass as a non-hazardous waste. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Acid effects on the measurement of mercury by cold vapor atomic absorption spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adeloju, S.B.; Mann, T.F.

    1987-07-01

    The influence of nitric, hydrochloric and sulfuric acids on the measurement of mercury by cold vapor atomic absorption spectrometry has been investigated. Small pre-reduction peaks associated with the instability of mercury were observed in solutions containing less than or equal to 12.5, < 2 and less than or equal to 12.5% v/v of each acid, respectively. Mercury was found to be most stable in greater than or equal to 2% v/v hydrochloric acid and the measured absorbance was not greatly influenced by varying concentration of the acid. The mercury absorbance measurements were more sensitive in solutions containing less than ormore » equal to 6.3% v/v hydrochloric acid than in similar concentrations of nitric and sulfuric acids. The use of the three acids as a digestion mixture result in serious interference from nitrogen oxides. The interference was removed by use of expelling agents such as urea and sulfamic acid or overcome by use of excess stannous chloride, prior to the reduction of mercury(II) ions. The determination of mercury in NBS albacore tuna using both of these approaches to overcome the interference problem proved to be successful.« less

  9. Determination of trace elements in automotive fuels by filter furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Anselmi, Anna; Tittarelli, Paolo; Katskov, Dmitri A.

    2002-03-01

    The determination of Cd, Cr, Cu, Pb and Ni was performed in gasoline and diesel fuel samples by electrothermal atomic absorption spectrometry using the Transverse Heated Filter Atomizer (THFA). Thermal conditions were experimentally defined for the investigated elements. The elements were analyzed without addition of chemical modifiers, using organometallic standards for the calibration. Forty-microliter samples were injected into the THFA. Gasoline samples were analyzed directly, while diesel fuel samples were diluted 1:4 with n-heptane. The following characteristic masses were obtained: 0.8 pg Cd, 6.4 pg Cr, 12 pg Cu, 17 pg Pb and 27 pg Ni. The limits of determination for gasoline samples were 0.13 μg/kg Cd, 0.4 μg/kg Cr, 0.9 μg/kg Cu, 1.5 μg/kg Pb and 2.5 μg/kg Ni. The corresponding limit of determination for diesel fuel samples was approximately four times higher for all elements. The element recovery was performed using the addition of organometallic compounds to gasoline and diesel fuel samples and was between 85 and 105% for all elements investigated.

  10. Development of a High-Resolution Laser Absorption Spectroscopy Method with Application to the Determination of Absolute Concentration of Gaseous Elemental Mercury in Air.

    PubMed

    Srivastava, Abneesh; Hodges, Joseph T

    2018-06-05

    Isotope dilution-cold-vapor-inductively coupled plasma mass spectrometry (ID-CV-ICPMS) has become the primary standard for measurement of gaseous elemental mercury (GEM) mass concentration. However, quantitative mass spectrometry is challenging for several reasons including (1) the need for isotopic spiking with a standard reference material, (2) the requirement for bias-free passive sampling protocols, (3) the need for stable mass spectrometry interface design, and (4) the time and cost involved for gas sampling, sample processing, and instrument calibration. Here, we introduce a high-resolution laser absorption spectroscopy method that eliminates the need for sample-specific calibration standards or detailed analysis of sample treatment losses. This technique involves a tunable, single-frequency laser absorption spectrometer that measures isotopically resolved spectra of elemental mercury (Hg) spectra of 6 1 S 0 ← 6 3 P 1 intercombination transition near λ = 253.7 nm. Measured spectra are accurately modeled from first-principles using the Beer-Lambert law and Voigt line profiles combined with literature values for line positions, line shape parameters, and the spontaneous emission Einstein coefficient to obtain GEM mass concentration values. We present application of this method for the measurement of the equilibrium concentration of mercury vapor near room temperature. Three closed systems are considered: two-phase mixtures of liquid Hg and its vapor and binary two-phase mixtures of Hg-air and Hg-N 2 near atmospheric pressure. Within the experimental relative standard uncertainty, 0.9-1.5% congruent values of the equilibrium Hg vapor concentration are obtained for the Hg-only, Hg-air, Hg-N 2 systems, in confirmation with thermodynamic predictions. We also discuss detection limits and the potential of the present technique to serve as an absolute primary standard for measurements of gas-phase mercury concentration and isotopic composition.

  11. Transgenic pigeonpea events expressing Cry1Ac and Cry2Aa exhibit resistance to Helicoverpa armigera.

    PubMed

    Ghosh, Gourab; Ganguly, Shreeparna; Purohit, Arnab; Chaudhuri, Rituparna Kundu; Das, Sampa; Chakraborti, Dipankar

    2017-07-01

    Independent transgenic pigeonpea events were developed using two cry genes. Transgenic Cry2Aa-pigeonpea was established for the first time. Selected transgenic events demonstrated 100% mortality of Helicoverpa armigera in successive generations. Lepidopteran insect Helicoverpa armigera is the major yield constraint of food legume pigeonpea. The present study was aimed to develop H. armigera-resistant transgenic pigeonpea, selected on the basis of transgene expression and phenotyping. Agrobacterium tumefaciens-mediated transformation of embryonic axis explants of pigeonpea cv UPAS 120 was performed using two separate binary vectors carrying synthetic Bacillus thuringiensis insecticidal crystal protein genes, cry1Ac and cry2Aa. T 0 transformants were selected on the basis of PCR and protein expression profile. T 1 events were exclusively selected on the basis of expression and monogenic character for cry, validated through Western and Southern blot analyses, respectively. Independently transformed 12 Cry1Ac and 11 Cry2Aa single-copy events were developed. The level of Cry-protein expression in T 1 transgenic events was 0.140-0.175% of total soluble protein. Expressed Cry1Ac and Cry2Aa proteins in transgenic pigeonpea exhibited significant weight loss of second-fourth instar larvae of H. armigera and ultimately 80-100% mortality in detached leaf bioassay. Selected Cry-transgenic pigeonpea events, established at T 2 generation, inherited insect-resistant phenotype. Immunohistofluorescence localization in T 3 plants demonstrated constitutive accumulation of Cry1Ac and Cry2Aa in leaf tissues of respective transgenic events. This study is the first report of transgenic pigeonpea development, where stable integration, effective expression and biological activity of two Cry proteins were demonstrated in subsequent three generations (T 0 , T 1, and T 2 ). These studies will contribute to biotechnological breeding programmes of pigeonpea for its genetic improvement.

  12. Constitutive behavior of as-cast AA1050, AA3104, and AA5182

    NASA Astrophysics Data System (ADS)

    van Haaften, W. M.; Magnin, B.; Kool, W. H.; Katgerman, L.

    2002-07-01

    Recent thermomechanical modeling to calculate the stress field in industrially direct-chill (DC) cast-aluminum slabs has been successful, but lack of material data limits the accuracy of these calculations. Therefore, the constitutive behavior of three aluminum alloys (AA1050, AA3104, and AA5182) was determined in the as-cast condition using tensile tests at low strain rates and from room temperature to solidus temperature. The parameters of two constitutive equations, the extended Ludwik equation and a combination of the Sellars-Tegart equation with a hardening law, were determined. In order to study the effect of recovery, the constitutive behavior after prestraining at higher temperatures was also investigated. To evaluate the quantified constitutive equations, tensile tests were performed simulating the deformation and cooling history experienced by the material during casting. It is concluded that both constitutive equations perform well, but the combined hardening-Sellars-Tegart (HST) equation has temperature-independent parameters, which makes it easier to implement in a DC casting model. Further, the deformation history of the ingot should be taken into account for accurate stress calculations.

  13. Memory immune response and safety of a booster dose of Japanese encephalitis chimeric virus vaccine (JE-CV) in JE-CV-primed children

    PubMed Central

    Feroldi, Emmanuel; Capeding, Maria Rosario; Boaz, Mark; Gailhardou, Sophia; Meric, Claude; Bouckenooghe, Alain

    2013-01-01

    Japanese encephalitis chimeric virus vaccine (JE-CV) is a licensed vaccine indicated in a single dose administration for primary immunization. This controlled phase III comparative trial enrolled children aged 36–42 mo in the Philippines. 345 children who had received one dose of JE-CV in a study two years earlier, received a JE-CV booster dose. 105 JE-vaccine-naïve children in general good health were randomized to receive JE-CV (JE-vaccine naïve group; 46 children) or varicella vaccine (safety control group; 59 children). JE neutralizing antibody titers were assessed using PRNT50. Immunological memory was observed in children who had received the primary dose of JE-CV before. Seven days after the JE-CV booster dose administration, 96.2% and 66.8% of children were seroprotected and had seroconverted, respectively, and the geometric mean titer (GMT) was 231 1/dil. Twenty-eight days after the JE-CV booster dose seroprotection and seroconversion were achieved in 100% and 95.3% of children, respectively, and the GMT was 2,242 1/dil. In contrast, only 15.4% of JE-CV-vaccine naïve children who had not received any prior JE vaccine were seroprotected seven days after they received JE-CV. One year after receiving the JE-CV booster dose, 99.4% of children remained seroprotected. We conclude that JE-CV is effective and safe, both as a single dose and when administrated as a booster dose. A booster dose increases the peak GMT above the peak level reached after primary immunization and the antibody persistence is maintained at least one year after the JE-CV booster dose administration. Five year follow up is ongoing. PMID:23442823

  14. Memory immune response and safety of a booster dose of Japanese encephalitis chimeric virus vaccine (JE-CV) in JE-CV-primed children.

    PubMed

    Feroldi, Emmanuel; Capeding, Maria Rosario; Boaz, Mark; Gailhardou, Sophia; Meric, Claude; Bouckenooghe, Alain

    2013-04-01

    Japanese encephalitis chimeric virus vaccine (JE-CV) is a licensed vaccine indicated in a single dose administration for primary immunization. This controlled phase III comparative trial enrolled children aged 36-42 mo in the Philippines. 345 children who had received one dose of JE-CV in a study two years earlier, received a JE-CV booster dose. 105 JE-vaccine-naïve children in general good health were randomized to receive JE-CV (JE-vaccine naïve group; 46 children) or varicella vaccine (safety control group; 59 children). JE neutralizing antibody titers were assessed using PRNT50. Immunological memory was observed in children who had received the primary dose of JE-CV before. Seven days after the JE-CV booster dose administration, 96.2% and 66.8% of children were seroprotected and had seroconverted, respectively, and the geometric mean titer (GMT) was 231 1/dil. Twenty-eight days after the JE-CV booster dose seroprotection and seroconversion were achieved in 100% and 95.3% of children, respectively, and the GMT was 2,242 1/dil. In contrast, only 15.4% of JE-CV-vaccine naïve children who had not received any prior JE vaccine were seroprotected seven days after they received JE-CV. One year after receiving the JE-CV booster dose, 99.4% of children remained seroprotected. We conclude that JE-CV is effective and safe, both as a single dose and when administrated as a booster dose. A booster dose increases the peak GMT above the peak level reached after primary immunization and the antibody persistence is maintained at least one year after the JE-CV booster dose administration. Five year follow up is ongoing.

  15. Negative Affect, Relapse, and Alcoholics Anonymous (AA): Does AA Work by Reducing Anger?*

    PubMed Central

    Kelly, John F.; Stout, Robert L.; Tonigan, J. Scott; Magill, Molly; Pagano, Maria E.

    2010-01-01

    Objective: Anger and other indices of negative affect have been implicated in a stress-induced pathway to relapse. The Alcoholics Anonymous (AA) literature states that reduction of anger is critical to recovery, yet this proposed mechanism has rarely been investigated. Using lagged, controlled hierarchical linear modeling analyses, this study investigated whether AA attendance mobilized changes in anger and whether such changes explained AA-related benefit. Method: Alcohol-dependent adults (N = 1,706) receiving treatment as part of a clinical trial were assessed at intake and at 3, 6, 9, 12, and 15 months. Results: Findings revealed substantially elevated levels of anger compared with the general population (98th percentile) that decreased over 15-month follow-up but remained high (89th percentile). AA attendance was associated with better drinking outcomes, and higher levels of anger were associated with heavier drinking. However, AA attendance was unrelated to changes in anger. Conclusions: Although support was not found for anger as a mediator, there was strong convergence between AA's explicit emphasis on anger and the present findings: Anger appears to be a serious, enduring problem related to relapse and heavy alcohol consumption. Methodological factors may have contributed to the lack of association between AA and anger, but results suggest that AA attendance alone may be insufficient to alleviate the suffering and alcohol-related risks specifically associated with anger. PMID:20409438

  16. [Determination of inorganic elements in different parts of Sonchus oleraceus L by flame atomic absorption spectrometry].

    PubMed

    Wang, Nai-Xing; Cui, Xue-Gui; Du, Ai-Qin; Mao, Hong-Zhi

    2007-06-01

    Flame atomic absorption spectrometry with air-acetylene flame was used for the determination of inorganic metal elements in different parts ( flower, leaf, stem and root) of Sonchus oleraceus L. The contents of Ca, Mg, K, Na, Fe, Mn, Cu, Zn, Cr, Co, Ni, Pb and Cd in the flower, leaf, stem and root of Sonchus oleraceus L were compared. The order from high to low of the additive weight (microg x g(-1)) for the 13 kinds of metal elements is as follows: leaf (77 213.72) > flower (47 927.15) > stem(42 280.99) > root (28 131.18). From the experimental results it was found that there were considerable differences in the contents of the metal elements in different parts, and there were richer contents of Fe, Zn, Mn and Cu in root and flower, which are necessary to human health, than in other parts.

  17. On-line ionic liquid-based preconcentration system coupled to flame atomic absorption spectrometry for trace cadmium determination in plastic food packaging materials.

    PubMed

    Martinis, Estefanía M; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-05-15

    A novel on-line preconcentration method based on liquid-liquid (L-L) extraction with room temperature ionic liquids (RTILs) coupled to flame atomic absorption spectrometry (FAAS) was developed for cadmium determination in plastic food packaging materials. The methodology is based on the complexation of Cd with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) reagent after sample digestion followed by extraction of the complex with the RTIL 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]). The mixture was loaded into a flow injection analysis (FIA) manifold and the RTIL rich-phase was retained in a microcolumn filled with silica gel. The RTIL rich-phase was then eluted directly into FAAS. A enhancement factor of 35 was achieved with 20 mL of sample. The limit of detection (LOD), obtained as IUPAC recommendation, was 6 ng g(-1) and the relative standard deviation (R.S.D.) for 10 replicates at 10 microg L(-1) Cd concentration level was 3.9%, calculated at the peak heights. The calibration graph was linear and a correlation coefficient of 0.9998 was achieved. The accuracy of the method was evaluated by both a recovery study and comparison of results with direct determination by electrothermal atomic absorption spectrometry (ETAAS). The method was successfully applied for Cd determination in plastic food packaging materials and Cd concentrations found were in the range of 0.04-10.4 microg g(-1).

  18. Identification of N-nitrosamines in treated drinking water using nanoelectrospray ionization high-field asymmetric waveform ion mobility spectrometry with quadrupole time-of-flight mass spectrometry.

    PubMed

    Zhao, Yuan Yuan; Liu, Xin; Boyd, Jessica M; Qin, Feng; Li, Jianjun; Li, Xing-Fang

    2009-01-01

    We report a nanoelectrospray ionization (nESI) with high-field asymmetric waveform ion mobility spectrometry (FAIMS) and tandem mass spectrometry (MS-MS) method for determination of small molecules of m/z 50 to 200 and its potential application in environmental analysis. Integration of nESI with FAIMS and MS-MS combines the advantages of these three techniques into one method. The nESI provides efficient sample introduction and ionization and allows for collection of multiple data from only microliters of samples. The FAIMS provides rapid separation, reduces or eliminates background interference, and improves the signal-to-noise ratio as much as 10-fold over nESI-MS-MS. The tandem quadrupole time-of-flight MS detection provides accurate mass and mass spectral measurements for structural identification. Characteristics of FAIMS compensation voltage (CV) spectra of seven nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosodi-n-butylamine (NDBA), N-nitrosopiperidine (NPip), and N-nitrosopyrrolidine (NPyr), were analyzed. The optimal CV of the nitrosamines (at DV -4000 V) were: -1.6 V, NDBA; 2.6 V, NDPA; 6.6 V, NPip; 8.8 V, NDEA; 13.2 V, NPyr; 14.4 V, NMEA; and 19.4 V, NDMA. Fragmentation patterns of the seven nitrosamines in the nESI-FAIMS-MS-MS were also obtained. The specific CV and MS-MS spectra resulted in positive identification of NPyr and NPip in a treated water sample, demonstrating the potential application of this technique in environmental analysis.

  19. Automated method for the determination of total arsenic and selenium in natural and drinking water by HG-AAS.

    PubMed

    Pistón, Mariela; Silva, Javier; Pérez-Zambra, Ramiro; Dol, Isabel; Knochen, Moisés

    2012-04-01

    A multicommutated flow system was designed and evaluated for the determination of total arsenic and selenium by Hydride Generation Atomic Absorption Spectrometry (HG-AAS). It was applied to the determination of arsenic and selenium in samples of natural and drinking water. Detection limits were 0.46 and 0.08 μg l(-1) for arsenic and selenium, respectively; sampling frequency was 120 samples h(-1) for arsenic and 160 samples h(-1) for selenium. Linear ranges found were 1.54-10 μg l(-1) (R = 0.999) for arsenic and 0.27-27 μg l(-1) (R = 0.999) for selenium. Accuracy was evaluated by spiking various water samples and using a reference material. Recoveries were in the range 95-116%. Analytical precision (s ( r ) (%), n = 10) was 6% for both elements. Compared with the Standard Methods, APHA, 3114B manual method, the system consumes at least 10 times less sample per determination, and the quantities of acid and reducing agent used are significantly lower with a reduction in the generation of pollutants and waste. As an additional advantage, the system is very fast, efficient and environmentally friendly for monitoring total arsenic and selenium levels in waters.

  20. [Establishment of embryogenic cell suspension culture and plant regeneration of edible banana Musa acuminata cv. Mas (AA)].

    PubMed

    Wei, Yue-Rong; Huang, Xue-Lin; Li, Jia; Huang, Xia; Li, Zhe; Li, Xiao-Ju

    2005-01-01

    Conventional breeding for dual resistance of disease and pest of Musa cultivars remains a difficult endeavor, as the plant is polyploidic and high in sterility. Biotechnological techniques, eg., genetic engineering, in vitro mutation breeding, or protoplast fusion, may overcome the difficulties and improve the germplasm. Establishment of a stable embryogenic cell suspension (ECS) is a prerequisite for any of the biotechnological breeding methods. In this study an embryogenic cell suspension was established from immature male flower of Musa acuminata cv. Mas (AA), a popular commercial variety of banana in the South-East Asian region. After culture for 5-6 months on callus induction media, which consisted of MS salts, different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), 4.1 micromol/L biotin, 5.7 micromol/L indoleacetic acid (IAA), 5.4 micromol/L naphthaleneacetic acid (NAA), other vitamins, 87 mmol/L sucrose, and solidified with 7 g/L agarose, meristematic globules and yellow, friable embryogenic cultures were induced from the explants of 1-15th row young floral hands of immature male flowers. Of the four treatments of 2,4-D, 9 micromol/L was the most effective on the callus induction, it transformed 40.96% and 7.45% of the cultivated male floral hands into callus and embryogenic callus respectively. The explants to produce highest frequency of the embryogenic calli were floral hands of 6 to 12th rows, which generated 5.79% of the embryogenic calli. Suspension cultures were initiated from these embryogenic calli in liquid medium supplemented with 4.5 micromol/L 2, 4-D. After sieving selection of the cultures using a stainless steel metallic strainer with pore sizes of 154 microm at 15 day intervals for 3 months, homogeneous and yellow embryogenic cell suspensions, composed of single cells and small cell aggregates, were established. Based upon the growth quantity and growth rate of ECS, it was determined that the appropriate inoculum was 2.0 mL PCV

  1. Determination of sulfur in bovine serum albumin and L-cysteine using high-resolution continuum source molecular absorption spectrometry of the CS molecule

    NASA Astrophysics Data System (ADS)

    Andrade-Carpente, Eva; Peña-Vázquez, Elena; Bermejo-Barrera, Pilar

    2016-08-01

    In this study, the content of sulfur in bovine serum albumin and L-cysteine was determined using high-resolution continuum source molecular absorption spectrometry of the CS molecule, generated in a reducing air-acetylene flame. Flame conditions (height above the burner, measurement time) were optimized using a 3.0% (v/v) sulfuric acid solution. A microwave lab station (Ethos Plus MW) was used for the digestion of both compounds. During the digestion step, sulfur was converted to sulfate previous to the determination. Good repeatability (4-10%) and analytical recovery (91-106%) was obtained.

  2. Direct analysis of environmental and biological samples for total mercury with comparison of sequential atomic absorption and fluorescence measurements from a single combustion event

    NASA Astrophysics Data System (ADS)

    Cizdziel, James V.; Tolbert, Candice; Brown, Garry

    2010-02-01

    A Direct Mercury Analyzer (DMA) based on sample combustion, concentration of mercury by amalgamation with gold, and cold vapor atomic absorption spectrometry (CVAAS) was coupled to a mercury-specific cold vapor atomic fluorescence spectrometer (CVAFS). The purpose was to evaluate combustion-AFS, a technique which is not commercially available, for low-level analysis of mercury in environmental and biological samples. The experimental setup allowed for comparison of dual measurements of mercury (AAS followed by AFS) for a single combustion event. The AFS instrument control program was modified to properly time capture of mercury from the DMA, avoiding deleterious combustion products from reaching its gold traps. Calibration was carried out using both aqueous solutions and solid reference materials. The absolute detection limits for mercury were 0.002 ng for AFS and 0.016 ng for AAS. Recoveries for reference materials ranged from 89% to 111%, and the precision was generally found to be <10% relative standard deviation (RSD). The two methods produced similar results for samples of hair, finger nails, coal, soil, leaves and food stuffs. However, for samples with mercury near the AAS detection limit (e.g., filter paper spotted with whole blood and segments of tree rings) the signal was still quantifiable with AFS, demonstrating the lower detection limit and greater sensitivity of AFS. This study shows that combustion-AFS is feasible for the direct analysis of low levels of mercury in solid samples that would otherwise require time-consuming and contamination-prone digestion.

  3. Determination of mercury in fish tissue using a minianalyzer based on cold vapor atomic absorption spectrometry at the 184.9 nm line.

    PubMed

    Rizea, Maria-Cristina; Bratu, Maria-Cristina; Danet, Andrei Florin; Bratu, Adrian

    2007-09-01

    A sensitive method was proposed and optimized for the determination of total mercury in fish tissue by using wet digestion, followed by cold vapor atomic absorption spectrometry (CVAAS) at the main resonance line of mercury (184.9 nm). The measurements were made using a new type of a non-dispersive mercury minianalyzer. This instrument was initially designed and built for atmospheric mercury-vapor detection. For determining mercury in aqueous samples, the minianalyzer was linked with a mercury/hydride system, Perkin Elmer Model MHS-10. To check the method, the analyzed samples were spiked with a standard solution of mercury. The recoveries of mercury spiked to wet fish tissue were >90% for 0.5 - 0.8 g samples. The results showed a better sensitivity (about 2.5 times higher) when using the mercury absorption line at 184.9 nm compared with the sensitivity obtained by conventional CVAAS at 253.7 nm.

  4. The cytochrome P450 2AA gene cluster in zebrafish (Danio rerio): Expression of CYP2AA1 and CYP2AA2 and response to phenobarbital-type inducers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kubota, Akira; Bainy, Afonso C.D.; Departamento de Bioquímica, CCB, Universidade Federal de Santa Catarina, Florianopolis, SC 88040-900

    2013-10-01

    The cytochrome P450 (CYP) 2 gene family is the largest and most diverse CYP gene family in vertebrates. In zebrafish, we have identified 10 genes in a new subfamily, CYP2AA, which does not show orthology to any human or other mammalian CYP genes. Here we report evolutionary and structural relationships of the 10 CYP2AA genes and expression of the first two genes, CYP2AA1 and CYP2AA2. Parsimony reconstruction of the tandem duplication pattern for the CYP2AA cluster suggests that CYP2AA1, CYP2AA2 and CYP2AA3 likely arose in the earlier duplication events and thus are most diverged in function from the other CYP2AAs.more » On the other hand, CYP2AA8 and CYP2AA9 are genes that arose in the latest duplication event, implying functional similarity between these two CYPs. A molecular model of CYP2AA1 showing the sequence conservation across the CYP2AA cluster reveals that the regions with the highest variability within the cluster map onto CYP2AA1 near the substrate access channels, suggesting differing substrate specificities. Zebrafish CYP2AA1 transcript was expressed predominantly in the intestine, while CYP2AA2 was most highly expressed in the kidney, suggesting differing roles in physiology. In the liver CYP2AA2 expression but not that of CYP2AA1, was increased by 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) and, to a lesser extent, by phenobarbital (PB). In contrast, pregnenolone 16α-carbonitrile (PCN) increased CYP2AA1 expression, but not CYP2AA2 in the liver. The results identify a CYP2 subfamily in zebrafish that includes genes apparently induced by PB-type chemicals and PXR agonists, the first concrete in vivo evidence for a PB-type response in fish. - Highlights: • A tandemly duplicated cluster of ten CYP2AA genes was described in zebrafish. • Parsimony and duplication analyses suggest pathways to CYP2AA diversity. • Homology models reveal amino acid positions possibly related to functional diversity. • The CYP2AA locus does not share

  5. Role of aortic arch vascular mechanics in cardiovagal baroreflex sensitivity.

    PubMed

    Klassen, Stephen A; Chirico, Daniele; Dempster, Kylie S; Shoemaker, J Kevin; O'Leary, Deborah D

    2016-07-01

    Cardiovagal baroreflex sensitivity (cvBRS) measures the efficiency of the cardiovagal baroreflex to modulate heart rate in response to increases or decreases in systolic blood pressure (SBP). Given that baroreceptors are located in the walls of the carotid sinuses (CS) and aortic arch (AA), the arterial mechanics of these sites are important contributors to cvBRS. However, the relative contribution of CS and AA mechanics to cvBRS remains unclear. This study employed sex differences as a model to test the hypothesis that differences in cvBRS between groups would be explained by the vascular mechanics of the AA but not the CS. Thirty-six young, healthy, normotensive individuals (18 females; 24 ± 2 yr) were recruited. cvBRS was measured using transfer function analysis of the low-frequency region (0.04-0.15 Hz). Ultrasonography was performed at the CS and AA to obtain arterial diameters for the measurement of distensibility. Local pulse pressure (PP) was taken at the CS using a hand-held tonometer, whereas AA PP was estimated using a transfer function of brachial PP. Both cvBRS (25 ± 11 vs. 19 ± 7 ms/mmHg, P = 0.04) and AA distensibility (16.5 ± 6.0 vs. 10.5 ± 3.8 mmHg(-1) × 10(-3), P = 0.02) were greater in females than males. Sex differences in cvBRS were eliminated after controlling for AA distensibility (P = 0.19). There were no sex differences in CS distensibility (5.32 ± 2.3 vs. 4.63 ± 1.3 mmHg(-1) × 10(-3), P = 0.32). The present data demonstrate that AA mechanics are an important contributor to differences in cvBRS. Copyright © 2016 the American Physiological Society.

  6. Determination of calcium, magnesium, sodium, and potassium in foodstuffs by using a microsampling flame atomic absorption spectrometric method after closed-vessel microwave digestion: method validation.

    PubMed

    Chekri, Rachida; Noël, Laurent; Vastel, Christelle; Millour, Sandrine; Kadar, Ali; Guérin, Thierry

    2010-01-01

    This paper describes a validation process in compliance with the NFIEN ISO/IEC 17025 standard for the determination of the macrominerals calcium, magnesium, sodium, and potassium in foodstuffs by microsampling with flame atomic absorption spectrometry after closed-vessel microwave digestion. The French Standards Commission (Agence Francaise de Normalisation) standards NF V03-110, NF EN V03-115, and XP T-90-210 were used to evaluate this method. The method was validated in the context of an analysis of the 1322 food samples of the second French Total Diet Study (TDS). Several performance criteria (linearity, LOQ, specificity, trueness, precision under repeatability conditions, and intermediate precision reproducibility) were evaluated. Furthermore, the method was monitored by several internal quality controls. The LOQ values obtained (25, 5, 8.3, and 8.3 mg/kg for Ca, Mg, Na, and K, respectively) were in compliance with the needs of the TDS. The method provided accurate results as demonstrated by a repeatability CV (CVr) of < 7% and a reproducibility CV (CVR) of < 12% for all the elements. Therefore, the results indicated that this method could be used in the laboratory for the routine determination of these four elements in foodstuffs with acceptable analytical performance.

  7. Solid sampling determination of total fluorine in baby food samples by high-resolution continuum source graphite furnace molecular absorption spectrometry.

    PubMed

    Ozbek, Nil; Akman, Suleyman

    2016-11-15

    This study describes the applicability of solid sampling technique for the determination of fluorine in various baby foods via molecular absorption of calcium monofluoride generated in a graphite furnace of high-resolution continuum source atomic absorption spectrometry. Fluorine was determined at CaF wavelength, 606.440nm in a graphite tube applying a pyrolysis temperature of 1000°C and a molecule forming temperature of 2200°C. The limit of detection and characteristic mass of the method were 0.20ng and 0.17ng of fluorine, respectively. The fluorine concentrations determined in standard reference sample (bush branches and leaves) were in good agreement with the certified values. By applying the optimized parameters, the concentration of fluorine in various baby foods were determined. The fluorine concentrations were ranged from

  8. Comparison of soil pollution concentrations determined using AAS and portable XRF techniques.

    PubMed

    Radu, Tanja; Diamond, Dermot

    2009-11-15

    Past mining activities in the area of Silvermines, Ireland, have resulted in heavily polluted soils. The possibility of spreading pollution to the surrounding areas through dust blow-offs poses a potential threat for the local communities. Conventional environmental soil and dust analysis techniques are very slow and laborious and consequently there is a need for fast and accurate analytical methods, which can provide real-time in situ pollution mapping. Laboratory-based aqua regia acid digestion of the soil samples collected in the area followed by the atomic absorption spectrophotometry (AAS) analysis confirmed very high pollution, especially by Pb, As, Cu, and Zn. In parallel, samples were analyzed using portable X-ray fluorescence radioisotope and miniature tube powered (XRF) NITON instruments and their performance was compared. Overall, the portable XRF instrument gave excellent correlation with the laboratory-based reference AAS method.

  9. Developing a Transdisciplinary Teaching Implement for Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Drew, John

    2008-01-01

    In this article I explain why I wrote the set of teaching notes on Atomic Absorption Spectroscopy (AAS) and why they look the way they do. The notes were intended as a student reference to question, highlight and write over as much as they wish during an initial practical demonstration of the threshold concept being introduced, in this case…

  10. Longitudinal study of experimental induction of AA amyloidosis in mice seeded with homologous and heterologous AA fibrils.

    PubMed

    Muhammad, Naeem; Murakami, Tomoaki; Inoshima, Yasuo; Ishiguro, Naotaka

    2016-09-01

    To investigate pathogenesis and kinetics of experimentally induced murine AA amyloidosis seeded with homologous (murine) and heterologous (bovine) AA fibrils. Experimental AA amyloidosis was induced by administration of inflammatory stimulus and preformed AA fibrils to a total of 111 female C57/Black mice. In this longitudinal study, heterologous (bovine) as well as homologous (murine) AA fibrils were injected intraperitoneally to mice in various combinations. Re-stimulation was done at 120 or 300 days post first inoculation. To analyze the intensity of amyloid depositions in mice organs, immunohistochemical techniques and image J software were used. Assessment of cytokines level in sera was done using a Mouse Th1/Th2/Th17 Cytokine CBA Kit. Incidence and severity of AA amyloidosis were quite low in mice inoculated with heterologous bovine AA fibrils than homologous murine one. Homologous AA fibrils administration at first and second inoculation caused maximum amount of amyloid depositions and severe systemic form of amyloidosis. Increase in the level of pro-inflammatory cytokine IL-6 was observed after first inoculation, while second inoculation caused a further increase in the level of anti-inflammatory cytokine IL-10. AA amyloidosis can be induced by heterologous as well as homologous AA fibrils. Severity of AA amyloidosis induced with homologous AA fibrils is higher compared to heterologous AA fibrils.

  11. Arachidonic acid with taurine enhances pulmonary absorption of macromolecules without any serious histopathological damages.

    PubMed

    Miyake, Masateru; Minami, Takanori; Yamazaki, Hiroyuki; Emoto, Chie; Mukai, Tadashi; Toguchi, Hajime

    2017-05-01

    Therapeutic peptides and protein are being used in several indications; however, their poor permeability still remains to be solved. This study focused on the pulmonary route of macromolecules. First, the effects of arachidonic acid (AA) as an absorption enhancer on drug serum concentration, after intratracheal administration, were investigated in rats. Second, the safety of AA was assessed in rats in an acute toxicity study for 7days. AA enhanced the exposure of both interferon-α (IFN-α) and fluorescein isothiocyanate 4000 (FD-4). In addition, the histopathological analysis indicated that AA caused alveolitis and bronchitis in rats. In combination with Taurine (Tau), these lung injuries were prevented through the histopathological analysis. The combined use of Tau with AA did not show any changes in the pharmacokinetics of FD-4. From these results, we suggest the combined use of AA with Tau as a novel formulation on the pulmonary route of macromolecule drugs. This formulation could improve the bioavailability of macromolecule drugs without any serious local damage to the lungs. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The CV period minimum

    NASA Astrophysics Data System (ADS)

    Kolb, Ulrich; Baraffe, Isabelle

    Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs we calculate the secular evolution of low-donor-mass CVs, including those which form with a brown dwarf donor star. Our models confirm the mismatch between the calculated minimum period (plus or minus in ~= 70 min) and the observed short-period cut-off (~= 80 min) in the CV period histogram. Theoretical period distributions synthesized from our model sequences always show an accumulation of systems at the minimum period, a feature absent in the observed distribution. We suggest that non-magnetic CVs become unobservable as they are effectively trapped in permanent quiescence before they reach plus or minus in, and that small-number statistics may hide the period spike for magnetic CVs. We calculate the minimum period for high mass transfer rate sequences and discuss the relevance of these for explaining the location of CV secondaries in the orbital-period-spectral-type diagram. We also show that a recently suggested revised mass-radius relation for low-mass main-sequence stars cannot explain the CV period gap.

  13. Metallic elements (Ca, Hg, Fe, K, Mg, Mn, Na, Zn) in the fruiting bodies of Boletus badius.

    PubMed

    Kojta, Anna K; Falandysz, Jerzy

    2016-06-01

    The aim of this study was to investigate and compare the levels of eight metallic elements in the fruiting bodies of Bay Bolete (Boletus badius; current name Imleria badia) collected from ten sites in Poland to understand better the value of this popular mushroom as an organic food. Bay Bolete fruiting bodies were collected from the forest area near the towns and villages of Kętrzyn, Poniatowa, Bydgoszcz, Pelplin, Włocławek, Żuromin, Chełmno, Ełk and Wilków communities, as well as in the Augustów Primeval Forest. Elements such as Ca, Fe, K, Mg, Mn, Na and Zn were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES), and mercury by cold vapor atomic absorption spectrometry (CV-AAS). This made it possible to assess the nutritional value of the mushroom, as well as possible toxicological risks associated with its consumption. The results were subjected to statistical analysis (Kruskal-Wallis test, cluster analysis, principal component analysis). Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Rapid and simple determination of selenium in blood serum by inductively coupled plasma-mass spectrometry (ICP-MS).

    PubMed

    Labat, L; Dehon, B; Lhermitte, M

    2003-05-01

    An inductively coupled plasma mass spectrometer (ICP-MS) with a rapid sample-preparative procedure was used for the determination of selenium in blood serum. Blood serum was prepared by dilution in an acidic solution consisting of nitric acid (1%), X-triton (0.1%) and 1-butanol (0.8%). A calibration curve was established for 1-40 microg mL(-1) (r(2)>0.99). The limit of detection was 0.5 microg mL(-1). Repeatability and intermediate precision were satisfactory with relative standard deviations (RSD) of 2.0% and 3.2%, respectively. This method was easily applied to reference materials with satisfactory accuracy. Good correlation (r(2)=0.96) was observed between ICP-MS and atomic absorption spectrometry (AAS) for the determination of (82)Se in blood serum from 23 patients. These results suggest that the sample preparative procedure coupled with ICP-MS can be used for the routine determination of (82)Se in human blood serum.

  15. Determination of mercury in an assortment of dietary supplements using an inexpensive combustion atomic absorption spectrometry technique.

    PubMed

    Levine, Keith E; Levine, Michael A; Weber, Frank X; Hu, Ye; Perlmutter, Jason; Grohse, Peter M

    2005-01-01

    The concentrations of mercury in forty, commercially available dietary supplements, were determined using a new, inexpensive analysis technique. The method involves thermal decomposition, amalgamation, and detection of mercury by atomic absorption spectrometry with an analysis time of approximately six minutes per sample. The primary cost savings from this approach is that labor-intensive sample digestion is not required prior to analysis, further automating the analytical procedure. As a result, manufacturers and regulatory agencies concerned with monitoring lot-to-lot product quality may find this approach an attractive alternative to the more classical acid-decomposition, cold vapor atomic absorption methodology. Dietary supplement samples analyzed included astragalus, calcium, chromium picolinate, echinacea, ephedra, fish oil, ginger, ginkgo biloba, ginseng, goldenseal, guggul, senna, St John's wort, and yohimbe products. Quality control samples analyzed with the dietary supplements indicated a high level of method accuracy and precision. Ten replicate preparations of a standard reference material (NIST 1573a, tomato leaves) were analyzed, and the average mercury recovery was 109% (2.0% RSD). The method quantitation limit was 0.3 ng, which corresponded to 1.5 ng/g sample. The highest found mercury concentration (123 ng/g) was measured in a concentrated salmon oil sample. When taken as directed by an adult, this product would result in an approximate mercury ingestion of 7 mug per week.

  16. Determination of gold and cobalt dopants in advanced materials based on tin oxide by slurry sampling high-resolution continuum source graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Filatova, Daria G.; Eskina, Vasilina V.; Baranovskaya, Vasilisa B.; Vladimirova, Svetlana A.; Gaskov, Alexander M.; Rumyantseva, Marina N.; Karpov, Yuri A.

    2018-02-01

    A novel approach is developed for the determination of Co and Au dopants in advanced materials based on tin oxide using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) with direct slurry sampling. Sodium carboxylmethylcellulose (Na-CMC) is an effective stabilizer for diluted suspensions. Use Na-CMC allows to transfer the analytes into graphite furnace completely and reproducibly. The relative standard deviation obtained by HR CS GFAAS was not higher than 4%. Accuracy was proven by means inductively coupled plasma mass spectrometry (ICP-MS) in solutions after decomposition as a comparative technique. To determine Au and Co in the volume of SnO2, the acid decomposition conditions (HCl, HF) of the samples were suggested by means of an autoclave in a microwave oven.

  17. Characterization of the radical-scavenging reaction of 2-O-substituted ascorbic acid derivatives, AA-2G, AA-2P, and AA-2S: a kinetic and stoichiometric study.

    PubMed

    Takebayashi, Jun; Tai, Akihiro; Gohda, Eiichi; Yamamoto, Itaru

    2006-04-01

    The aim of this study was to characterize the antioxidant activity of three ascorbic acid (AA) derivatives O-substituted at the C-2 position of AA: ascorbic acid 2-glucoside (AA-2G), ascorbic acid 2-phosphate (AA-2P), and ascorbic acid 2-sulfate (AA-2S). The radical-scavenging activities of these AA derivatives and some common low molecular-weight antioxidants such as uric acid or glutathione against 1,1-diphenyl-picrylhydrazyl (DPPH) radical, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+), or galvinoxyl radical were kinetically and stoichiometrically evaluated under pH-controlled conditions. Those AA derivatives slowly and continuously reacted with DPPH radical and ABTS+, but not with galvinoxyl radical. They effectively reacted with DPPH radical under acidic conditions and with ABTS+ under neutral conditions. In contrast, AA immediately quenched all species of radicals tested at all pH values investigated. The reactivity of Trolox, a water-soluble vitamin E analogue, was comparable to that of AA in terms of kinetics and stoichiometrics. Uric acid and glutathione exhibited long-lasting radical-scavenging activity against these radicals under certain pH conditions. The radical-scavenging profiles of AA derivatives were closer to those of uric acid and glutathione rather than to that of AA. The number of radicals scavenged by one molecule of AA derivatives, uric acid, or glutathione was equal to or greater than that by AA or Trolox under the appropriate conditions. These data suggest the potential usage of AA derivatives as radical scavengers.

  18. Determination of mercury by multisyringe flow injection system with cold-vapor atomic absorption spectrometry.

    PubMed

    Leal, L O; Elsholz, O; Forteza, R; Cerdà, V

    2006-07-28

    A new software-controlled time-based multisyringe flow injection system for mercury determination by cold-vapor atomic absorption spectrometry is proposed. Precise known volumes of sample, reducing agent (1.1% SnCl2 in 3% HCl) and carrier (3% HCl) are dispensed into a gas-liquid separation cell with a multisyringe burette coupled with one three-way solenoid valve. An argon flow delivers the reduced mercury to the spectrometer. The optimization of the system was carried out testing reaction coils and gas-liquid separators of different design as well as changing parameters, such as sample and reagents volumes, reagent concentrations and carrier gas flow rate, among others. The analytical curves were obtained within the range 50-5000 ng L(-1). The detection limit (3sigma(b)/S) achieved is 5 ng L(-1). The relative standard deviation (R.S.D.) was 1.4%, evaluated from 16 successive injections of 250 ng L(-1) Hg standard solution. The injection and sample throughput per hour were 44 and 11, respectively. This technique was validated by means of solid and water reference materials with good agreement with the certified values and was successfully applied to fish samples.

  19. Detection of AA76, a Common Form of Amyloid A Protein, as a Way of Diagnosing AA Amyloidosis.

    PubMed

    Sato, Junji; Okuda, Yasuaki; Kuroda, Takeshi; Yamada, Toshiyuki

    2016-01-01

    Reactive amyloid deposits consist of amyloid A (AA) proteins, the degradation products of serum amyloid A (SAA). Since the most common species of AA is the amino terminal portion produced by cleavage between residues 76 and 77 of SAA (AA76), the presence of AA76 in tissues could be a consequence of AA amyloid deposition. This study assessed the diagnostic significance of the detection of AA76 for AA amyloidosis using two different approaches. Biopsy specimens (n=130 from 54 subjects) from gastroduodenal mucosa or abdominal fat (n=9 from 9 subjects) of patients who had already been diagnosed with or were suspected of having AA amyloidosis were used. Fixed mucosal sections were subjected to immunohistochemistry using a newly developed antibody recognizing the carboxyl terminal end of AA76 (anti-AA76). The non-fixed materials from gastroduodenal mucosa or abdominal fat were subjected to immunoblotting for detection of the size of AA76. Among the gastroduodenal specimens (n=115) from already diagnosed patients, the positive rates of Congo red staining, immunohistochemistry using anti-AA76, and immunoblotting were 68.4%, 73.0%, and 92.2%, respectively. The anti-AA76 did not stain the supposed SAA in the blood or leakage, which was stained by anti-SAA antibody. AA76 was not detected either by immunohistochemistry or by immunoblot in the materials from patients in whom AA amyloidosis had been ruled out. In the abdominal fat, the immunoblot detected AA76 in 8 materials from 8 already diagnosed patients and did not in 1 patient whose gastroduodenal mucosa was negative. In conclusion, the detection of AA76 may alter the ability to diagnose AA amyloidosis. In immunohistochemistry for fixed specimens, the new anti-AA76 antibody can improve the specificity. Immunoblot for non-fixed materials, which can considerably improve the sensitivity, should be beneficial for small materials like abdominal fat. © 2016 by the Association of Clinical Scientists, Inc.

  20. Instrumentation and optimization of intra-cavity fiber laser gas absorption sensing system

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Liu, Tiegen; Jiang, Junfeng; Liang, Xiao; Zhang, Yimo

    2011-11-01

    Detection of pollution, inflammable, explosive gases such as methane, acetylene, carbon monoxide and so on is very important for many areas, such as environmental, mining and petrochemical industry. Intra-cavity gas absorption sensing technique (ICGAST) based on Erbium-doped fiber ring laser (EDFRL) is one of novel methods for trace gas with higher precision. It has attracted considerable attention, and many research institutes focus on it. Instrumentation and optimization of ICGAST was reported in this paper. The system consists of five parts, which are variable gain module, intelligent frequency-selection module, gas cell, DAQ module and computer respectively. Variable gain module and intelligent frequency-selection module are combined to establish the intra-cavity of the ring laser. Gas cell is used as gas sensor. DAQ module is used to realize data acquisition synchronously. And gas demodulation is finished in the computer finally. The system was optimized by adjusting the sequence of the components. Take experimental simulation as an example, the absorptance of gas was increased five times after optimization, and the sensitivity enhancement factor can reach more than twenty. By using Fabry-Perot (F-P) etalon, the absorption wavelength of the detected gas can be obtained, with error less than 20 pm. The spectra of the detected gas can be swept continuously to obtain several absorption lines in one loop. The coefficient of variation (CV) was used to show the repeatability of gas concentration detection. And results of CV value can be less than 0.014.

  1. Sedimentation field flow fractionation and optical absorption spectroscopy for a quantitative size characterization of silver nanoparticles.

    PubMed

    Contado, Catia; Argazzi, Roberto; Amendola, Vincenzo

    2016-11-04

    Many advanced industrial and biomedical applications that use silver nanoparticles (AgNPs), require that particles are not only nano-sized, but also well dispersed, not aggregated and not agglomerated. This study presents two methods able to give rapidly sizes of monodispersed AgNPs suspensions in the dimensional range of 20-100nm. The first method, based on the application of Mie's theory, determines the particle sizes from the values of the surface plasmon resonance wavelength (SPR MAX ), read from the optical absorption spectra, recorded between 190nm and 800nm. The computed sizes were compared with those determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS) and resulted in agreement with the nominal values in a range between 13% (for 20nm NPs) and 1% (for 100nm NPs), The second method is based on the masterly combination of the Sedimentation Field Flow Fractionation (SdFFF - now sold as Centrifugal FFF-CFFF) and the Optical Absorption Spectroscopy (OAS) techniques to accomplish sizes and quantitative particle size distributions for monodispersed, non-aggregated AgNPs suspensions. The SdFFF separation abilities, well exploited to size NPs, greatly benefits from the application of Mie's theory to the UV-vis signal elaboration, producing quantitative mass-based particle size distributions, from which trusted number-sized particle size distributions can be derived. The silver mass distributions were verified and supported by detecting off-line the Ag concentration with the graphite furnace atomic absorption spectrometry (GF-AAS). Copyright © 2016 Elsevier B.V. All rights reserved.

  2. The effect of different propolis harvest methods on its lead contents determined by ET AAS and UV-visS.

    PubMed

    Sales, A; Alvarez, A; Areal, M Rodriguez; Maldonado, L; Marchisio, P; Rodríguez, M; Bedascarrasbure, E

    2006-10-11

    Argentinean propolis is exported to different countries, specially Japan. The market demands propolis quality control according to international standards. The analytical determination of some metals, as lead in food, is very important for their high toxicity even in low concentrations and because of their harmful effects on health. Flavonoids, the main bioactive compounds of propolis, tend to chelate metals as lead, which becomes one of the main polluting agents of propolis. The lead found in propolis may come from the atmosphere or it may be incorporated in the harvest, extraction and processing methods. The aim of this work is to evaluate lead level on Argentinean propolis determined by electrothermal atomic absorption spectrometry (ET AAS) and UV-vis spectrophotometry (UV-visS) methods, as well as the effect of harvest methods on those contents. A randomized test with three different treatments of collection was made to evaluate the effect of harvest methods. These procedures were: separating wedges (traditional), netting plastic meshes and stamping out plastic meshes. By means of the analysis of variance technique for multiple comparisons (ANOVA) it was possible to conclude that there are significant differences between scraped and mesh methods (stamped out and mosquito netting meshes). The results obtained in the present test would allow us to conclude that mesh methods are more advisable than scraped ones in order to obtain innocuous and safe propolis with minor lead contents. A statistical comparison of lead determination by both, ET AAS and UV-visS methods, demonstrated that there is not a significant difference in the results achieved with the two analytical techniques employed.

  3. [Determination of Al, Be, Cd, Co, Cr, Mn, Ni, Pb, Se and Tl in whole blood by atomic absorption spectrometry without preliminary sample digestion].

    PubMed

    Ivanenko, N B; Ivanenko, A A; Solov'ev, N D; Navolotskiĭ, D V; Pavlova, O V; Ganeev, A A

    2014-01-01

    Methods of whole blood trace element determination by Graphite furnace atomic absorption spectrometry (in the variant of Zeeman's modulation polarization spectrometry) have been proposed. They do not require preliminary sample digestion. Furnace programs, modifiers and blood dilution factors were optimized. Seronorm™ human whole blood reference materials were used for validation. Dynamic ranges (for undiluted blood samples) were: Al 8 ¸ 210 мg/L; Be 0.3 ¸ 50 мg/L; Cd 0.2 ¸ 75 мg/L; Сo 5 ¸ 350 мg/L; Cr 10 ¸ 100 мg/L; Mn 6 ¸ 250 мg/L; Ni 10 ¸ 350 мg/L; Pb 3 ¸ 240 мg/L; Se 10 ¸ 500 мg/L; Tl 2 ¸ 600 мg/L. Precision (RSD) for the middle of dynamic range ranged from 5% for Mn to 11 for Se.

  4. Matching the laser wavelength to the absorption properties of matrices increases the ion yield in UV-MALDI mass spectrometry.

    PubMed

    Wiegelmann, Marcel; Soltwisch, Jens; Jaskolla, Thorsten W; Dreisewerd, Klaus

    2013-09-01

    A high analytical sensitivity in ultraviolet matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is only achieved if the laser wavelength corresponds to a high optical absorption of the matrix. Laser fluence and the physicochemical properties of the compounds, e.g., the proton affinity, also influence analytical sensitivity significantly. In combination, these parameters determine the amount of material ejected per laser pulse and the ion yield, i.e., the fraction of ionized biomolecules. Here, we recorded peptide ion signal intensities as a function of these parameters. Three cinnamic acid matrices were investigated: α-cyano-4-hydroxycinnamic acid, α-cyano-4-chlorocinnamic acid, and α-cyano-2,4-difluorocinnamic acid. In addition, 2,5-dihydroxybenzoic acid was used in comparison experiments. Ion signal intensities "per laser shot" and integrated ion signal intensities were acquired over 900 consecutive laser pulses applied on distinct positions on the dried-droplet sample preparations. With respect to laser wavelength, the two standard MALDI wavelengths of 337/355 nm were investigated. Also, 305 or 320 nm was selected to account for the blue-shifted absorption profiles of the halogenated derivatives. Maximal peptide ion intensities were obtained if the laser wavelength fell within the peak of the absorption profile of the compound and for fluences two to three times the corresponding ion detection threshold. The results indicate ways for improving the analytical sensitivity in MALDI-MS, and in particular for MALDI-MS imaging applications where a limited amount of material is available per irradiated pixel.

  5. Quantification of absorption, retention and elimination of two different oral doses of vitamin A in Zambian boys using accelerator mass spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aklamati, E K; Mulenga, M; Dueker, S R

    A recent survey indicated that high-dose vitamin A supplements (HD-VAS) had no apparent effect on vitamin A (VA) status of Zambian children <5 y of age. To explore possible reasons for the lack of response to HD-VAS among Zambian children, we quantified the absorption, retention, and urinary elimination of either a single HDVAS (60 mg) or a smaller dose of stable isotope (SI)-labeled VA (5 mg), which was used to estimate VA pool size, in 3-4 y old Zambian boys (n = 4 for each VA dose). A 25 nCi tracer dose of [{sup 14}C{sub 2}]-labeled VA was co-administered withmore » the HD-VAS or SI-labeled VA, and 24-hr stool and urine samples were collected for 3 and 7 consecutive days, respectively, and 24-hr urine samples at 4 later time points. Accelerator Mass Spectrometry (AMS) was used to measure the cumulative excretion of {sup 14}C in stool and urine 3d after dosing to estimate, respectively, absorption and retention of the VAS and SI-labeled VA. The urinary elimination rate (UER) was estimated by plotting {sup 14}C in urine vs. time, and fitting an exponential equation to the data. Estimates of mean absorption, retention and the UER were 83.8 {+-} 7.1%, 76.3 {+-} 6.7%, and 1.9 {+-} 0.6%/d, respectively, for the HD-VAS and 76.5 {+-} 9.5%, 71.1 {+-} 9.4%, and 1.8 {+-} 1.2%/d, respectively for the smaller dose of SI-labeled VA. Estimates of absorption, retention and the UER did not differ by size of the VA dose administered (P=0.26, 0.40, 0.88, respectively). Estimated absorption and retention were negatively associated with reported fever (P=0.011) and malaria (P =0.010). HD-VAS and SI-labeled VA were adequately absorbed, retained and utilized in apparently healthy Zambian preschool-age boys, although absorption and retention may be affected by recent infections.« less

  6. Final report on CCQM-K70: Determination of Hg in natural water at a concentration level required by the European environmental quality standard (EQS)

    NASA Astrophysics Data System (ADS)

    Schiel, Detlef; Rienitz, Olaf

    2011-01-01

    This comparison 'Hg in natural water' was a follow-up to the pilot studies CCQM-P100.1 and CCQM-P100.2. The aim of this comparison was to demonstrate the capability of national metrology institutes to measure the Hg mass concentration in a natural water sample at the very low concentration level of γ(Hg) ≈ 70 ng/L as required by the EQS. In this way it served to help implement the European Water Framework Directive (WFD). This comparison was an activity of the Inorganic Analysis Working Group (IAWG) of CCQM and was piloted by Physikalisch-Technische Bundesanstalt (PTB, Braunschweig, Germany) with the help of the co-organizers Bundesanstalt für Materialforschung und -prüfung (BAM, Berlin, Germany), Laboratoire National de Métrologie et d'Essais (LNE, Paris, France), and the Joint Research Centre-Institute for Reference Materials and Measurements (EC-JRC-IRMM, Geel, Belgium). The following laboratories participated in this key comparison (in alphabetical order): BAM (Germany) EC-JRC-IRMM (European Union) KRISS (Republic of Korea) LGC (United Kingdom) LNE (France) NIST (United States of America) NMIA (Australia) NRC (Canada) PTB (Germany) SP (Sweden) The majority of participants applied isotope dilution mass spectrometry (IDMS) using sector field or quadrupole inductively coupled plasma MS (ICP-MS) in combination with cold vapour (CV) generation as the analytical technique. NRC reported a combined result of ID-CV-ICP-MS and CV atomic absorption spectrometry (CV-AAS). SP applied a standard addition method on a sector field ICP-MS, while BAM made use of an external 5-point calibration on a CV atomic fluorescence spectrometer (AFS). The key comparison reference value (KCRV) was agreed upon during the IAWG meeting in April 2010 at BIPM as the sum of the added Hg content calculated from the gravimetric sample preparation and the Hg matrix content of the water used for sample preparation (determined and validated on two independent pathways). Accordingly the degrees

  7. Method of trivalent chromium concentration determination by atomic spectrometry

    DOEpatents

    Reheulishvili, Aleksandre N [Tbilisi, 0183, GE; Tsibakhashvili, Neli Ya [Tbilisi, 0101, GE

    2006-12-12

    A method is disclosed for determining the concentration of trivalent chromium Cr(III) in a sample. The addition of perchloric acid has been found to increase the atomic chromium spectrometric signal due to Cr(III), while leaving the signal due to hexavalent chromium Cr(VI) unchanged. This enables determination of the Cr(III) concentration without pre-concentration or pre-separation from chromium of other valences. The Cr(III) concentration may be measured using atomic absorption spectrometry, atomic emission spectrometry or atomic fluorescence spectrometry.

  8. Tungsten devices in analytical atomic spectrometry

    NASA Astrophysics Data System (ADS)

    Hou, Xiandeng; Jones, Bradley T.

    2002-04-01

    Tungsten devices have been employed in analytical atomic spectrometry for approximately 30 years. Most of these atomizers can be electrically heated up to 3000 °C at very high heating rates, with a simple power supply. Usually, a tungsten device is employed in one of two modes: as an electrothermal atomizer with which the sample vapor is probed directly, or as an electrothermal vaporizer, which produces a sample aerosol that is then carried to a separate atomizer for analysis. Tungsten devices may take various physical shapes: tubes, cups, boats, ribbons, wires, filaments, coils and loops. Most of these orientations have been applied to many analytical techniques, such as atomic absorption spectrometry, atomic emission spectrometry, atomic fluorescence spectrometry, laser excited atomic fluorescence spectrometry, metastable transfer emission spectroscopy, inductively coupled plasma optical emission spectrometry, inductively coupled plasma mass spectrometry and microwave plasma atomic spectrometry. The analytical figures of merit and the practical applications reported for these techniques are reviewed. Atomization mechanisms reported for tungsten atomizers are also briefly summarized. In addition, less common applications of tungsten devices are discussed, including analyte preconcentration by adsorption or electrodeposition and electrothermal separation of analytes prior to analysis. Tungsten atomization devices continue to provide simple, versatile alternatives for analytical atomic spectrometry.

  9. Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically labeled 14C-cobalamin

    PubMed Central

    Carkeet, Colleen; Dueker, Stephen R.; Lango, Jozsef; Buchholz, Bruce A.; Miller, Joshua W.; Green, Ralph; Hammock, Bruce D.; Roth, John R.; Anderson, Peter J.

    2006-01-01

    There is a need for an improved test of human ability to assimilate dietary vitamin B12. Assaying and understanding absorption and uptake of B12 is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 (14C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of 14C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B12 in the range of normal dietary intake. The B12 used was quantitatively labeled with 14C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B12 or two of its precursors, cobinamide and DMB. When provided with 14C-DMB specifically labeled in the C2 position, cells produced 14C-B12 of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 μg, 2.2 kBq/59 nCi) of purified 14C-B12 was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B12 assimilation. PMID:16585531

  10. Relationship between light scattering and absorption due to cytochrome c oxidase reduction during loss of tissue viability in brains of rats

    NASA Astrophysics Data System (ADS)

    Kawauchi, Satoko; Sato, Shunichi; Ooigawa, Hidetoshi; Nawashiro, Hiroshi; Ishihara, Miya; Kikuchi, Makoto

    2008-02-01

    We performed simultaneous measurement of light scattering and absorption due to reduction of cytochrome c oxidase as intrinsic optical signals that are related to morphological characteristics and energy metabolism, respectively, for rat brains after oxygen/glucose deprivation by saline infusion. To detect change in light scattering, we determined the wavelength that was the most insensitive to change in light absorption due to the reduction of cytochrome c oxidase on the basis of multiwavelength analysis of diffuse reflectance data set for each rat. Then the relationships between scattering signal and absorption signals related to the reductions of heme aa 3 (605 nm) and CuA (830 nm) in cytochrome c oxidase were examined. Measurements showed that after starting saline infusion, the reduction of heme aa 3 started first; thereafter triphasic, large scattering change occurred (200-300 s), during which the reduction of CuA started. Despite such complex behaviors of IOSs, almost linear correlations were seen between the scattering signal and the heme aa 3-related absorption signal, while a relatively large animal-to-animal variation was observed in the correlation between the scattering signal and CuA-related absorption signal. Transmission electron microscopic observation revealed that dendritic swelling and mitochondrial deformation occurred in the cortical surface tissue after the triphasic scattering change. These results suggest that mitochondrial energy failure accompanies morphological alteration in the brain tissue and results in change in light scattering; light scattering will become an important indicator of tissue viability in brain.

  11. [Risk control of traditional Chinese medicines containing aristolochis acids (AAs) based on influencing factors of content of AAs].

    PubMed

    Tian, Jing-Zhuo; Liang, Ai-Hua; Liu, Jing; Zhang, Bo-Li

    2017-12-01

    Aristolochic acids (AAs) widely exist in such plants as Aristolochia and Asarum. The renal toxicity of AAs as well as its carcinogenicity to urinary system have been widely known. In 2003 and 2004, China prohibited the use of Aristolochiae Radix, Aristolochiae Manshuriensis Caulis and Aristolochiae Fangchi Radix, and required administering other AAs-containing medicines in accordance with the regulations for prescription drugs. In this paper, we retrieved literatures on the content determination of AAs in recent 10 years in China. It suggested that the AAs content is lower in Asarum herb, especially in its roots and rhizomes, and most of which do not show detectable amount of AA-I. Some of traditional Chinese medicines show fairly small amount of detectable AA-I. The AAs content in Aristolochia herb (including Fructus Aristolochiae, kaempfer dutchmanspipe root) is relatively high; however, there are fewer literatures for studying the content determination of AAs in Chinese patent medicines. There were many factors affecting AAs content, including the parts used, origins, processing methods, extraction process. It suggested that we should pay attention to the toxicity of Chinese medicines containing AAs and use these decoction pieces and traditional Chinese medicines cautiously. In addition, basic studies for the origins, processing methods and extraction process of Chinese patent medicines containing AAs, as well as supervision and detection of AAs content in traditional Chinese medicinal materials, decoction pieces and Chinese patent medicines shall be strengthened for reducing medication risk and guaranteeing clinical medication safety. Copyright© by the Chinese Pharmaceutical Association.

  12. A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry.

    PubMed

    Tuzen, Mustafa; Soylak, Mustafa; Citak, Demirhan; Ferreira, Hadla S; Korn, Maria G A; Bezerra, Marcos A

    2009-03-15

    A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 microg L(-1), respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 microg L(-1). The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.

  13. Determination of trace concentrations of chlorine in aqueous solutions by high-resolution continuum source graphite furnace molecular absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Machyňák, Ľubomír; Čacho, František; Němeček, Martin; Beinrohr, Ernest

    2016-11-01

    Trace concentrations of total chlorine were determined by means of molecular absorption of indium mono-chloride (InCl) at 267.217 nm using high-resolution continuum source graphite furnace molecular absorption spectrometry. The effects of chemical modifiers and the amount of In on the sensitivity and accuracy were investigated. The optimum pyrolysis and vaporization temperatures were 600 °C and 1400 °C, respectively. The limit of detection and characteristic mass were found to be 0.10 ng and 0.21 ng, respectively. Potential non-spectral and spectral interferences were tested for various metals and non-metals at concentrations up to 50 mg L- 1 and for phosphoric, sulphuric and nitric acids. No spectral interferences were observed. Significant non-spectral interferences were observed with F, Br, and I at concentrations higher than 1 mg L- 1, 5 mg L- 1 and 25 mg L- 1, respectively, which is probably caused by formation of competitive indium halogen molecules. Higher concentrations of mineral acids depressed the signal owing to the formation of volatile HCl. The calibration curve was linear in the range between 0.3 and 10 ng with a correlation coefficient of R = 0.993. The elaborated method was used for the chlorine determination in various waters and a drug sample.

  14. Concentration and distribution of sixty-one elements in coals from DPR Korea

    USGS Publications Warehouse

    Hu, Jiawen; Zheng, B.; Finkelman, R.B.; Wang, B.; Wang, M.; Li, S.; Wu, D.

    2006-01-01

    Fifty coal samples (28 anthracite and 22 lignites) were collected from both main and small coal mines in DPR Korea prioritized by resource distribution and coal production. The concentrations of 61 elements in 50 coal samples were determined by several multielement and element-specific techniques, including inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS), ion chromatogram (IC), cold-vapor atomic absorption spectrometry (CV-AAS), and hydride generation atomic absorption spectrometry (HGAAS). The ranges, arithmetic means and geometric means of concentrations of these elements are presented. A comparison with crustal abundances (Clarke values) shows that some potentially hazardous elements in the coals of DPR Korea are highly enriched Li, B, S, Cl, Zn, As, Se, Cd, Sn, Sb, W, Te, Hg, Ag, Pb, and La, Ce, Dy, Tm, Ge, Mo, Cs, Tl, Bi, Th and U are moderately enriched. A comparison of ranges and means of elemental concentrations in DPR Korea, Chinese, and world coals shows the ranges of most elements in DPR Korea coals are very close to the ranges of world coals. Arithmetic means of most elements in DPR Korea coals are close to that of American coals. Most elements arithmetic means are higher in Jurassic and Paleogene coals than coals of other ages. In DPR Korea coals, only seven elements in early Permian coals are higher than other periods: Li, Zn, Se, Cd, Hg, Pb, and Bi. Only five elements B, As, Sr, Mo, W in Neogene coals have arithmetic means higher than others. SiO2 and Al2O 3 in ashes are more than 70% except six samples. The correlation between ash yields and major elements from high to low is in the order of Si>Al>Ti>K>Mg>Fe>Na>Ca>P>S. Most elements have high positive correlation with ash (r>0.5) and show high inorganic affinity. ?? 2005 Elsevier Ltd. All rights reserved.

  15. Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: A multivariate study

    NASA Astrophysics Data System (ADS)

    Arain, Salma Aslam; Kazi, Tasneem G.; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

    2014-12-01

    An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu2+) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu2+ using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046 μg L-1 and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu2+ in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu2+ in serum samples of different viral hepatitis patients and healthy controls.

  16. The Moss Techniques for Air Pollution Study in Bulgaria

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Marinova, S.; Marinov, A.; Frontasyeva, M.

    2010-01-21

    The paper presents new results on atmospheric deposition of 41 elements in four areas of Bulgaria during the European moss survey in 2005. The results have been obtained by the moss biomonitoring technique. Ninety seven moss samples were analyzed by instrumental neutron activation analysis (ENAA) and atomic absorption spectrometry (AAS).

  17. Increasing the throughput and productivity of Caco-2 cell permeability assays using liquid chromatography-mass spectrometry: application to resveratrol absorption and metabolism.

    PubMed

    Li, Yongmei; Shin, Young Geun; Yu, Chongwoo; Kosmeder, Jerome W; Hirschelman, Wendy H; Pezzuto, John M; van Breemen, Richard B

    2003-12-01

    The Caco-2 cell monolayer permeability assay has become a standard model of human intestinal absorption and transport. This paper reviews recent progress in increasing the throughput of Caco-2 cell monolayer assays and in expanding the scope of this assay to include modeling intestinal drug metabolism. The state-of-the-art in Caco-2 cell monolayer permeability assays combines multi-well plates fitted with semi-permeable inserts on which Caco-2 cells have been cultured with liquid chromatography-mass spectrometry (LC-MS) or LC-tandem mass spectrometry (LC-MS-MS) for the quantitative analysis of test compounds and the identification of their intestinal metabolites. After reviewing the progress in increasing the throughput of Caco-2 cell monolayer assays for both modeling human intestinal permeability or transport and the metabolism of xenobiotic compounds, we demonstrate the application of LC-MS and LC-MS-MS to the measurement of resveratrol permeability and metabolism in the Caco-2 model. trans-Resveratrol (trans-3,5,4'-trihydroxystilbene) is a polyphenolic compound occurring in grapes, peanuts and other food sources, that is under investigation as a cancer chemoprevention agent. The apparent permeability coefficient for apical (AP) to basolateral (BL) movement of resveratrol was 2.0 x 10(-5)cm/sec. Resveratrol was not a substrate for P-glycoprotein or the multi-drug resistance associated proteins (MRP). No phase I metabolites were observed, but the phase II conjugates resveratrol-3-glucuronide and resveratrol-3-sulfate was identified based on LC-MS and LC-MS-MS analysis and comparison with synthetic standards. Although these data indicate that resveratrol diffuses rapidly across the intestinal epithelium, extensive phase II metabolism during absorption might reduce resveratrol bioavailability.

  18. Self-assembling of impurity clusters in AlN:(Ga, BV, CV), (BV, CV = P, As; P, Sb; As, Sb)

    NASA Astrophysics Data System (ADS)

    Elyukhin, V. A.

    2015-11-01

    The self-assembling conditions of arrays of tetrahedral impurity clusters of two types in zinc blende AlN:(Ga, BV, CV), (BV, CV = P, As; P, Sb; As, Sb) are represented. Doping with one cation and two anion isoelectronic impurities transforms AlN into AlN-rich GaxAl1-xBVyCVzN1-y-z alloy of GaBV, GaCV, GaN, AlBV, AlCV and AlN. The cause of self-assembling is the preference of GaBV, GaCV and AlN bonding over that of GaN, AlBV, AlCV. The conditions are considered from 0 °C to 1000 °C in the dilute and ultra dilute limits for the cation and anion impurities, correspondingly. The temperature ranges between the cluster occurrence and self-assembling completion when the same anion impurities are in clusters are very small. 1P4Ga and 1As4Ga cluster occurrence temperatures are equal, correspondingly, to 797 °C and 736 °C at Ga content 2% and P and As contents 0.01%. 1P4Ga and 1Sb4Ga cluster occurrence temperatures are equal, correspondingly, to 976 °C and 736 °C at the same impurity contents. The cluster densities in AlN:(Ga, As, Sb) are close to those in AlN:(Ga, P, Sb). The results demonstrate that studied semiconductors are promising materials to produce arrays of identical ∼1 nm low band gap objects of two types embedded in the wide band gap matrix.

  19. Analysis of an Air Conditioning Coolant Solution for Metal Contamination Using Atomic Absorption Spectroscopy: An Undergraduate Instrumental Analysis Exercise Simulating an Industrial Assignment

    ERIC Educational Resources Information Center

    Baird, Michael J.

    2004-01-01

    A real-life analytical assignment is presented to students, who had to examine an air conditioning coolant solution for metal contamination using an atomic absorption spectroscopy (AAS). This hands-on access to a real problem exposed the undergraduate students to the mechanism of AAS, and promoted participation in a simulated industrial activity.

  20. Sol gel method for synthesis of semiconducting ferrite and the study of FTIR, DTA, SEM and CV

    NASA Astrophysics Data System (ADS)

    Alva, Sagir; Hua, Tang Ing; Kalmar Nizar, Umar; Wahyudi, Haris; Sundari, Rita

    2018-03-01

    In this study, a sol gel method using citric acid as anionic surfactant is used for synthesis of magnesium ferrite. Calcinations of magnesium ferrite at temperature (300°C, 600°C and 800°C) have been conducted after sol gel process. Characterization study of the prepared magnesium ferrite related to calcinations using Fourier transform infrared spectrometry (FTIR), Differential thermogravic analysis (DTA), and Scanning electron microscope (SEM) has been discussed. The study of Cyclic voltammetry (CV) of the prepared magnesium ferrite has been examined to assay the semiconducting behavior of magnesium ferrite in relation to its electrochemical behavior.

  1. The relationship between CK and CV chondrites

    NASA Astrophysics Data System (ADS)

    Greenwood, R. C.; Franchi, I. A.; Kearsley, A. T.; Alard, O.

    2010-03-01

    CK chondrites are highly oxidized meteorites containing abundant magnetite and trace amounts of Fe,Ni metal. Although the group is predominately composed of equilibrated meteorites (types 4-6), in recent years a significant number of new samples have been classified as being either CK3 or CK3-anomalous. These unequilibrated CKs often display a close affinity with members of the CV oxidized subgroup. CKs and CVs (oxidized subgroup) may therefore form a continuum and by implication could be derived from a single common parent body. To investigate the relationship between these two groups a detailed study of the oxygen isotope composition, opaque mineralogy and major and trace element geochemistry of a suite of CV and CK chondrites has been undertaken. The results of oxygen isotope analysis confirm the close affinity between CV and CK chondrites, while excluding the possibility of a linkage between the CO and CK groups. Magnetites in both CV and CK chondrites show significant compositional similarities, but high Ti contents are a diagnostic feature of the latter group. The results of major and trace element analysis demonstrate that both CV and CK chondrites show overlapping variation. Supporting evidence for a single common source for both groups comes from their similar cosmic-ray exposure age distributions. Recent reflectance spectral analysis is consistent with both the CVs and CKs being derived from Eos family asteroids, which are believed to have formed by the catastrophic disruption of a single large asteroid. Thus, a range of evidence appears to be consistent with CV and CK chondrites representing samples from a single thermally stratified parent body. In view of the close similarity between CV and CK chondrites some modification of the present classification scheme may be warranted, possibly involving integration of the two groups. One means of achieving this would be to reassigned CK chondrites to a subgroup of the oxidized CVs. It is recognized that a full

  2. Accuracy of trace element determinations in alternate fuels

    NASA Technical Reports Server (NTRS)

    Greenbauer-Seng, L. A.

    1980-01-01

    NASA-Lewis Research Center's work on accurate measurement of trace level of metals in various fuels is presented. The differences between laboratories and between analytical techniques especially for concentrations below 10 ppm, are discussed, detailing the Atomic Absorption Spectrometry (AAS) and DC Arc Emission Spectrometry (dc arc) techniques used by NASA-Lewis. Also presented is the design of an Interlaboratory Study which is considering the following factors: laboratory, analytical technique, fuel type, concentration and ashing additive.

  3. Working towards accreditation by the International Standards Organization 15189 Standard: how to validate an in-house developed method an example of lead determination in whole blood by electrothermal atomic absorption spectrometry.

    PubMed

    Garcia Hejl, Carine; Ramirez, Jose Manuel; Vest, Philippe; Chianea, Denis; Renard, Christophe

    2014-09-01

    Laboratories working towards accreditation by the International Standards Organization (ISO) 15189 standard are required to demonstrate the validity of their analytical methods. The different guidelines set by various accreditation organizations make it difficult to provide objective evidence that an in-house method is fit for the intended purpose. Besides, the required performance characteristics tests and acceptance criteria are not always detailed. The laboratory must choose the most suitable validation protocol and set the acceptance criteria. Therefore, we propose a validation protocol to evaluate the performance of an in-house method. As an example, we validated the process for the detection and quantification of lead in whole blood by electrothermal absorption spectrometry. The fundamental parameters tested were, selectivity, calibration model, precision, accuracy (and uncertainty of measurement), contamination, stability of the sample, reference interval, and analytical interference. We have developed a protocol that has been applied successfully to quantify lead in whole blood by electrothermal atomic absorption spectrometry (ETAAS). In particular, our method is selective, linear, accurate, and precise, making it suitable for use in routine diagnostics.

  4. Degradation of some representative polycyclic aromatic hydrocarbons by the water-soluble protein extracts from Zea mays L. cv PR32-B10.

    PubMed

    Barone, Roberto; de Biasi, Margherita-Gabriella; Piccialli, Vincenzo; de Napoli, Lorenzo; Oliviero, Giorgia; Borbone, Nicola; Piccialli, Gennaro

    2016-10-01

    The ability of the water-soluble protein extracts from Zea mais L. cv. PR32-B10 to degrade some representative polycyclic aromatic hydrocarbons (PAHs), has been evaluated. Surface sterilized seeds of corn (Zea mais L. Pioneer cv. PR32-B10) were hydroponically cultivated in a growth chamber under no-stressful conditions. The water-soluble protein extracts isolated from maize tissues showed peroxidase, polyphenol oxidase and catalase activities. Incubation of the extracts with naphthalene, fluorene, phenanthrene and pyrene, led to formation of oxidized and/or degradation products. GC-MS and TLC monitoring of the processes showed that naphthalene, phenanthrene, fluorene and pyrene underwent 100%, 78%, 92% and 65% oxidative degradation, respectively, after 120 min. The chemical structure of the degradation products were determined by (1)H NMR and ESI-MS spectrometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Graphene oxide sheets immobilized polystyrene for column preconcentration and sensitive determination of lead by flame atomic absorption spectrometry.

    PubMed

    Islam, Aminul; Ahmad, Hilal; Zaidi, Noushi; Kumar, Suneel

    2014-08-13

    A novel solid-phase extractant was synthesized by coupling graphene oxide (GO) on chloromethylated polystyrene through an ethylenediamine spacer unit to develop a column method for the preconcentration/separation of lead prior to its determination by flame atomic absorption spectrometry. It was characterized by Fourier transform infrared spectroscopy, far-infrared spectroscopy, thermogravimetric analysis/differential thermal analysis, scanning electron microscopy, energy-dispersive spectrometry, and transmission electron microscopy. The abundant oxygen-containing surface functional groups form a strong complex with lead, resulting in higher sorption capacity (227.92 mg g(-1)) than other nanosorbents used for sorption studies of the column method. Using the column procedure here is an alternative to the direct use of GO, which restricts irreversible aggregation of GO and its escape into the ecosystem, making it an environmentally sustainable method. The column method was optimized by varying experimental variables such as pH, flow rate for sorption/desorption, and elution condition and was observed to exhibit a high preconcentration factor (400) with a low preconcentration limit (2.5 ppb) and a high degree of tolerance for matrix ions. The accuracy of the proposed method was verified by determining the Pb content in the standard reference materials and by recovery experiments. The method showed good precision with a relative standard deviation <5%. The proposed method was successfully applied for the determination of lead in tap water, electroplating wastewater, river water, and food samples after preconcentration.

  6. Opaque Assemblages in CK and CV Carbonaceous Chondrites

    NASA Technical Reports Server (NTRS)

    Neff, K. E.; Righter, K.

    2006-01-01

    CK carbonaceous chondrites are the only group of carbonaceous chondrites that exhibit thermal metamorphism. As a result, CKs display features of metamorphism such as silicate darkening, recrystallization and shock veins. Calcium Aluminum Inclusions and Fe-Ni metal are rare. CV carbonaceous chondrites are unequilibrated and have two subgroups; oxidized and reduced. The CV and CK carbonaceous chondrite groups have been compared to each other often because of petrographic similarities, such as overlapping oxygen isotopic ratios. Scientists have suggested the two groups of carbonaceous chondrites formed from the same parent body and CKs are equilibrated CV chondrites [1, 2]. The oxidized CV group has been most closely related to CKs. This study examines the petrology and mineralogy of CKs and CVs focusing on opaque minerals found in the meteorites. Using the oxide, metal and sulfide assemblages, constraints can be placed on the temperature and oxygen fugacity at which the meteorites equilibrated. The temperature and oxygen fugacity of the CK and CV chondrites can be compared in order to help define their formation history.

  7. Determination of phospholipids in soybean lecithin samples via the phosphorus monoxide molecule by high-resolution continuum source graphite furnace molecular absorption spectrometry.

    PubMed

    Pires, Laís N; Brandão, Geovani C; Teixeira, Leonardo S G

    2017-06-15

    This paper presents a method for determining phospholipids in soybean lecithin samples by phosphorus determination using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) via molecular absorption of phosphorus monoxide. Samples were diluted in methyl isobutyl ketone. The best conditions were found to be 213.561nm with a pyrolysis temperature of 1300°C, a volatilization temperature of 2300°C and Mg as a chemical modifier. To increase the analytical sensitivity, measurement of the absorbance signal was obtained by summing molecular transition lines for PO surrounding 213nm: 213.561, 213.526, 213.617 and 213.637nm. The limit of detection was 2.35mgg -1 and the precision, evaluated as relative standard deviation (RSD), was 2.47% (n=10) for a sample containing 2.2% (w/v) phosphorus. The developed method was applied for the analysis of commercial samples of soybean lecithin. The determined concentrations of phospholipids in the samples varied between 38.1 and 45% (w/v). Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Application of Internal Standard Method for Several 3d-Transition Metallic Elements in Flame Atomic Absorption Spectrometry Using a Multi-wavelength High-resolution Spectrometer.

    PubMed

    Toya, Yusuke; Itagaki, Toshiko; Wagatsuma, Kazuaki

    2017-01-01

    We investigated a simultaneous internal standard method in flame atomic absorption spectrometry (FAAS), in order to better the analytical precision of 3d-transition metals contained in steel materials. For this purpose, a new spectrometer system for FAAS, comprising a bright xenon lamp as the primary radiation source and a high-resolution Echelle monochromator, was employed to measure several absorption lines at a wavelength width of ca. 0.3 nm at the same time, which enables the absorbances of an analytical line and also an internal standard line to be estimated. In considering several criteria for selecting an internal standard element and the absorption line, it could be suggested that platinum-group elements: ruthenium, rhodium, or palladium, were suitable for an internal standard element to determine the 3d-transition metal elements, such as titanium, iron, and nickel, by measuring an appropriate pair of these absorption lines simultaneously. Several variances of the absorption signal, such as a variation in aspirated amounts of sample solution and a short-period drift of the primary light source, would be corrected and thus reduced, when the absorbance ratio of the analytical line to the internal standard line was measured. In Ti-Pd, Ni-Rh, and Fe-Ru systems chosen as typical test samples, the repeatability of the signal respnses was investigated with/without the internal standard method, resulting in better precision when the internal standard method was applied in the FAAS with a nitrous oxide-acetylene flame rather than an air-acetylene flame.

  9. Identification of a "glycine-loop"-like coiled structure in the 34 AA Pro,Gly,Met repeat domain of the biomineral-associated protein, PM27.

    PubMed

    Wustman, Brandon A; Santos, Rudolpho; Zhang, Bo; Evans, John Spencer

    2002-12-05

    Fracture resistance in biomineralized structures has been linked to the presence of proteins, some of which possess sequences that are associated with elastic behavior. One such protein superfamily, the Pro,Gly-rich sea urchin intracrystalline spicule matrix proteins, form protein-protein supramolecular assemblies that modify the microstructure and fracture-resistant properties of the calcium carbonate mineral phase within embryonic sea urchin spicules and adult sea urchin spines. In this report, we detail the identification of a repetitive keratin-like "glycine-loop"- or coil-like structure within the 34-AA (AA: amino acid) N-terminal domain, (PGMG)(8)PG, of the spicule matrix protein, PM27. The identification of this repetitive structural motif was accomplished using two capped model peptides: a 9-AA sequence, GPGMGPGMG, and a 34-AA peptide representing the entire motif. Using CD, NMR spectrometry, and molecular dynamics simulated annealing/minimization simulations, we have determined that the 9-AA model peptide adopts a loop-like structure at pH 7.4. The structure of the 34-AA polypeptide resembles a coil structure consisting of repeating loop motifs that do not exhibit long-range ordering. Given that loop structures have been associated with protein elastic behavior and protein motion, it is plausible that the 34-AA Pro,Gly,Met repeat sequence motif in PM27 represents a putative elastic or mobile domain. Copyright 2002 Wiley Periodicals, Inc.

  10. Numerical approximations of the mean absorption cross-section of a variety of randomly oriented microalgal shapes.

    PubMed

    Baird, Mark E

    2003-10-01

    The size, shape, and absorption coefficient of a microalgal cell determines, to a first order approximation, the rate at which light is absorbed by the cell. The rate of absorption determines the maximum amount of energy available for photosynthesis, and can be used to calculate the attenuation of light through the water column, including the effect of packaging pigments within discrete particles. In this paper, numerical approximations are made of the mean absorption cross-section of randomly oriented cells, aA. The shapes investigated are spheroids, rectangular prisms with a square base, cylinders, cones and double cones with aspect ratios of 0.25, 0.5, 1, 2, and 4. The results of the numerical simulations are fitted to a modified sigmoid curve, and take advantage of three analytical solutions. The results are presented in a non-dimensionalised format and are independent of size. A simple approximation using a rectangular hyperbolic curve is also given, and an approach for obtaining the upper and lower bounds of aA for more complex shapes is outlined.

  11. Determination of Lead in Urine by Atomic Absorption Spectrophotometry1

    PubMed Central

    Selander, Stig; Cramé, Kim

    1968-01-01

    A method for the determination of lead in urine by means of atomic absorption spectrophotometry (AAS) is described. A combination of wet ashing and extraction with ammonium pyrrolidine dithiocarbamate into isobutylmethylketone was used. The sensitivity was about 0·02 μg./ml. for 1% absorption, and the detection limit was about 0·02 μg./ml. with an instrumental setting convenient for routine analyses of urines. Using the scale expansion technique, the detection limit was below 0·01 μg./ml., but it was found easier to determine urinary lead concentrations below 0·05 μg./ml. by concentrating the lead in the organic solvent by increasing the volume of urine or decreasing that of the solvent. The method was applied to fresh urines, stored urines, and to urines, obtained during treatment with chelating agents, of patients with lead poisoning. Urines with added inorganic lead were not used. The results agreed well with those obtained with a colorimetric dithizone extraction method (r = 0·989). The AAS method is somewhat more simple and allows the determination of smaller lead concentrations. PMID:5647975

  12. A comparison of laser ablation-inductively coupled plasma-mass spectrometry and high-resolution continuum source graphite furnace molecular absorption spectrometry for the direct determination of bromine in polymers

    NASA Astrophysics Data System (ADS)

    de Gois, Jefferson S.; Van Malderen, Stijn J. M.; Cadorim, Heloisa R.; Welz, Bernhard; Vanhaecke, Frank

    2017-06-01

    This work describes the development and comparison of two methods for the direct determination of Br in polymer samples via solid sampling, one using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and the other using high-resolution continuum source graphite furnace molecular absorption spectrometry with direct solid sample analysis (HR-CS SS-GF MAS). The methods were optimized and their accuracy was evaluated by comparing the results obtained for 6 polymeric certified reference materials (CRMs) with the corresponding certified values. For Br determination with LA-ICP-MS, the 79Br+ signal could be monitored interference-free. For Br determination via HR-CS SS-GF MAS, the CaBr molecule was monitored at 625.315 nm with integration of the central pixel ± 1. Bromine quantification by LA-ICP-MS was performed via external calibration against a single CRM while using the 12C+ signal as an internal standard. With HR-CS SS-GF MAS, Br quantification could be accomplished using external calibration against aqueous standard solutions. Except for one LA-ICP-MS result, the concentrations obtained with both techniques were in agreement with the certified values within the experimental uncertainty as evidenced using a t-test (95% confidence level). The limit of quantification was determined to be 100 μg g- 1 Br for LA-ICP-MS and 10 μg g- 1 Br for HR-CS SS-GF MAS.

  13. Rapid determination of six carcinogenic primary aromatic amines in mainstream cigarette smoke by two-dimensional online solid phase extraction combined with liquid chromatography tandem mass spectrometry.

    PubMed

    Bie, Zhenying; Lu, Wei; Zhu, You; Chen, Yusong; Ren, Hubo; Ji, Lishun

    2017-01-27

    A fully automated, rapid, and reliable method for simultaneous determination of six carcinogenic primary aromatic amines (AAs), including o-toluidine (o-TOL), 2, 6-dimethylaniline (2, 6-DMA), o-anisidine (o-ASD), 1-naphthylamine (1-ANP), 2-naphthylamine (2-ANP), and 4-aminobiphenyl (4-ABP), in mainstream cigarette smoke was established. The proposed method was based on two-dimensional online solid phase extraction combined with liquid chromatography tandem mass spectrometry (SPE/LC-MS/MS). The particulate phase of the mainstream cigarette smoke was collected on a Cambridge filter pad and pretreated via ultrasonic extraction with 2% formic acid (FA), while the gas phase was trapped by 2% FA without pretreatment for determination. The two-dimensional online SPE comprised of two cartridges with different absorption characteristics was applied for sample pretreatment. Analysis was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) under multiple reaction monitoring mode. Each sample required about 0.5h for solid phase extraction and analysis. The limit of detections (LODs) for six AAs ranged from 0.04 to 0.58ng/cig and recoveries were within 84.5%-122.9%. The relative standard deviations of intra- and inter-day tests for 3R4F reference cigarette were less than 6% and 7%, respectively, while no more than 7% and 8% separately for a type of Virginia cigarette. The proposed method enabled minimum sample pretreatment, full automation, and high throughput with high selectivity, sensitivity, and accuracy. As a part of the validation procedure, fifteen brands of cigarettes were tested by the designed method. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Determination of arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc in geological materials by atomic-absorption spectrometry

    USGS Publications Warehouse

    Viets, J.G.; O'Leary, R. M.; Clark, Robert J.

    1984-01-01

    Arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc are very useful elements in geochemical exploration. In the proposed method, geological samples are fused with potassium pyrosulphate and the fusate is dissolved in a solution of hydrochloric acid, ascorbic acid and potassium iodide. When this solution is shaken with a 10% V/V Aliquat 336 - isobutyl methyl ketone organic phase, the nine elements of interest are selectively partitioned in the organic phase. All nine elements can then be determined in the organic phase using flame atomic-absorption spectrometry. The method is rapid and allows the determination of Ag and Cd at levels down to 0.1 p.p.m., Cu, Mo, and Zn down to 0.5 p.p.m., Pb, Bi and Sb down to 1 p.p.m. and As down to 5 p.p.m. in geological materials.

  15. Determination of silver, bismuth, cadmium, copper, lead, and zinc in geologic materials by atomic absorption spectrometry with tricaprylylmethylammonium chloride

    USGS Publications Warehouse

    Viets, J.G.

    1978-01-01

    Interferences commonly encountered in the determination of silver, bismuth, cadmium, copper, lead, and zinc at crustal abundance levels are effectively eliminated using a rapid, sensitive, organic extraction technique. A potassium chlorate-hydrochloric acid digestion solubilizes the metals not tightly bound in the silicate lattice of rocks, soils, and stream sediments. The six metals are selectively extracted into a 10% Aliquat 336-MIBK organic phase in the presence of ascorbic acid and potassium iodide. Metals in the organic extract are determined by flame atomic absorption spectrometry to the 0.02-ppm level for silver, cadmium, copper, and zinc and to the 0.2-ppm level for bismuth and lead with a maximum relative standard deviation of 18.8% for known reference samples. An additional hydrofluoric acid digestion may be used to determine metals substituted in the silicate lattice.

  16. Determination of lithium isotopes at natural abundance levels by atomic absorption spectrometry

    USGS Publications Warehouse

    Meier, A.L.

    1982-01-01

    The relationships of the absorption of 6Li and 7Li hollow cathode lamp emissions are used to determine lithium isotopic composition in the natural abundance range of geologic materials. Absorption was found to have a nonlinear dependence upon total lithium concentration and isotopic composition. A method using nonlinear equations to describe the relationship of the absorption of 6Li and 7Li lamp radiation is proposed as a means of calculating isotopic composition that is independent of total lithium concentration.

  17. Laboratory Astrophysics Division of The AAS (LAD)

    NASA Astrophysics Data System (ADS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-10-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  18. Laboratory Astrophysics Division of the AAS (LAD)

    NASA Technical Reports Server (NTRS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-01-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  19. Mesoporous Silica Nanoparticles as an Adsorbent for Preconcentration and Determination of Trace Amount of Nickel in Environmental Samples by Atom Trap Flame Atomic Absorption Spectrometry

    NASA Astrophysics Data System (ADS)

    Shirkhanloo, H.; Falahnejad, M.; Zavvar Mousavi, H.

    2016-01-01

    A rapid enrichment method based on solid-phase extraction (SPE) has been established for preconcentration and separation of trace Ni(II) ions in water samples prior to their determination by atom trap flame atomic absorption spectrometry. A column filled with bulky NH2-UVM7 was used as the novel adsorbent. Under optimal conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were 3-92 μg/L, 0.8 μg/L, and 100, respectively. The validity of the method was checked by the standard reference material.

  20. Determination of gold in geologic materials by solvent extraction and atomic-absorption spectrometry

    USGS Publications Warehouse

    Huffman, Claude; Mensik, J.D.; Riley, L.B.

    1967-01-01

    The two methods presented for the determination of traces of gold in geologic materials are the cyanide atomic-absorption method and the fire-assay atomic-absorption method. In the cyanide method gold is leached with a sodium-cyanide solution. The monovalent gold is then oxidized to the trivalent state and concentrated by extracting into methyl isobutyl ketone prior to estimation by atomic absorption. In the fire-assay atomic-absorption method, the gold-silver bead obtained from fire assay is dissolved in nitric and hydrochloric acids. Gold is then concentrated by extracting into methyl isobutyl ketone prior to determination by atomic absorption. By either method concentrations as low as 50 parts per billion of gold can be determined in a 15-gram sample.

  1. Profiling monoterpenol glycoconjugation in Vitis vinifera L. cv. Muscat of Alexandria using a novel putative compound database approach, high resolution mass spectrometry and collision induced dissociation fragmentation analysis.

    PubMed

    Hjelmeland, Anna K; Zweigenbaum, Jerry; Ebeler, Susan E

    2015-08-05

    In this work we present a novel approach for the identification of plant metabolites using ultrahigh performance liquid chromatography coupled to accurate mass time-of-flight mass spectrometry. The workflow involves developing an in-house compound database consisting of exact masses of previously identified as well as putative compounds. The database is used to screen accurate mass spectrometry (MS) data to identify possible compound matches. Subsequent tandem MS data is acquired for possible matches and used for structural elucidation. The methodology is applied to profile monoterpene glycosides in Vitis vinifera cv. Muscat of Alexandria grape berries over three developmental stages. Monoterpenes are a subclass of terpenes, the largest class of plant secondary metabolites, and are found in two major forms in the plant, "bound" to one or more sugar moieties or "free" of said sugar moieties. In the free form, monoterpenes are noted for their fragrance and play important roles in plant defense and as attractants for pollinators. However, glycoconjugation renders these compounds odorless, and it is this form that the plant uses for monoterpene storage. In order to gain insight into monoterpene biochemistry and their fate in the plant an analysis of intact glycosides is essential. Eighteen monoterpene glycosides were identified including a monoterpene trisaccharide glycoside, which is tentatively identified here for this first time in any plant. Additionally, while previous studies have identified monoterpene malonylated glucosides in other grapevine tissue, we tentatively identify them for the first time in grape berries. This analytical approach can be readily applied to other plants and the workflow approach can also be used for other classes of compounds. This approach, in general, provides researchers with data to support the identification of putative compounds, which is especially useful when no standard is available. Copyright © 2015 Elsevier B.V. All rights

  2. Measurement of free radical kinetics in pulsed plasmas by UV and VUV absorption spectroscopy and by modulated beam mass spectrometry

    NASA Astrophysics Data System (ADS)

    Cunge, G.; Bodart, P.; Brihoum, M.; Boulard, F.; Chevolleau, T.; Sadeghi, N.

    2012-04-01

    This paper reviews recent progress in the development of time-resolved diagnostics to probe high-density pulsed plasma sources. We focus on time-resolved measurements of radicals' densities in the afterglow of pulsed discharges to provide useful information on production and loss mechanisms of free radicals. We show that broad-band absorption spectroscopy in the ultraviolet and vacuum ultraviolet spectral domain and threshold ionization modulated beam mass spectrometry are powerful techniques for the determination of the time variation of the radicals' densities in pulsed plasmas. The combination of these complementary techniques allows detection of most of the reactive species present in industrial etching plasmas, giving insights into the physico-chemistry reactions involving these species. As an example, we discuss briefly the radicals' kinetics in the afterglow of a SiCl4/Cl2/Ar discharge.

  3. Long-Term Fungal Inhibitory Activity of Water-Soluble Extracts of Phaseolus vulgaris cv. Pinto and Sourdough Lactic Acid Bacteria during Bread Storage▿

    PubMed Central

    Coda, Rossana; Rizzello, Carlo G.; Nigro, Franco; De Angelis, Maria; Arnault, Philip; Gobbetti, Marco

    2008-01-01

    The antifungal activity of proteinaceous compounds from different food matrices was investigated. In initial experiments, water-soluble extracts of wheat sourdoughs, cheeses, and vegetables were screened by agar diffusion assays with Penicillium roqueforti DPPMAF1 as the indicator fungus. Water-soluble extracts of sourdough fermented with Lactobacillus brevis AM7 and Phaseolus vulgaris cv. Pinto were selected for further study. The crude water-soluble extracts of L. brevis AM7 sourdough and P. vulgaris cv. Pinto had a MIC of 40 mg of peptide/ml and 30.9 mg of protein/ml, respectively. MICs were markedly lower when chemically synthesized peptides or partially purified protein fractions were used. The water-soluble extract of P. vulgaris cv. Pinto showed inhibition toward a large number of fungal species isolated from bakeries. Phaseolin alpha-type precursor, phaseolin, and erythroagglutinating phytohemagglutinin precursor were identified in the water-soluble extract of P. vulgaris cv. Pinto by nano liquid chromatography-electrospray ionization-tandem mass spectrometry. When the antifungal activity was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, all three proteins were inhibitory. A mixture of eight peptides was identified from the water-soluble extract of sourdough L. brevis AM7, and five of these exhibited inhibitory activity. Bread was made at the pilot plant scale by sourdough fermentation with L. brevis AM7 and addition of the water-soluble extract (27%, vol/wt; 5 mg of protein/ml) of P. vulgaris cv. Pinto. Slices of bread packed in polyethylene bags did not show contamination by fungi until at least 21 days of storage at room temperature, a level of protection comparable to that afforded by 0.3% (wt/wt) calcium propionate. PMID:18849463

  4. Long-term fungal inhibitory activity of water-soluble extracts of Phaseolus vulgaris cv. Pinto and sourdough lactic acid bacteria during bread storage.

    PubMed

    Coda, Rossana; Rizzello, Carlo G; Nigro, Franco; De Angelis, Maria; Arnault, Philip; Gobbetti, Marco

    2008-12-01

    The antifungal activity of proteinaceous compounds from different food matrices was investigated. In initial experiments, water-soluble extracts of wheat sourdoughs, cheeses, and vegetables were screened by agar diffusion assays with Penicillium roqueforti DPPMAF1 as the indicator fungus. Water-soluble extracts of sourdough fermented with Lactobacillus brevis AM7 and Phaseolus vulgaris cv. Pinto were selected for further study. The crude water-soluble extracts of L. brevis AM7 sourdough and P. vulgaris cv. Pinto had a MIC of 40 mg of peptide/ml and 30.9 mg of protein/ml, respectively. MICs were markedly lower when chemically synthesized peptides or partially purified protein fractions were used. The water-soluble extract of P. vulgaris cv. Pinto showed inhibition toward a large number of fungal species isolated from bakeries. Phaseolin alpha-type precursor, phaseolin, and erythroagglutinating phytohemagglutinin precursor were identified in the water-soluble extract of P. vulgaris cv. Pinto by nano liquid chromatography-electrospray ionization-tandem mass spectrometry. When the antifungal activity was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, all three proteins were inhibitory. A mixture of eight peptides was identified from the water-soluble extract of sourdough L. brevis AM7, and five of these exhibited inhibitory activity. Bread was made at the pilot plant scale by sourdough fermentation with L. brevis AM7 and addition of the water-soluble extract (27%, vol/wt; 5 mg of protein/ml) of P. vulgaris cv. Pinto. Slices of bread packed in polyethylene bags did not show contamination by fungi until at least 21 days of storage at room temperature, a level of protection comparable to that afforded by 0.3% (wt/wt) calcium propionate.

  5. Rapid quantification of underivatized amino acids in plasma by hydrophilic interaction liquid chromatography (HILIC) coupled with tandem mass-spectrometry.

    PubMed

    Prinsen, Hubertus C M T; Schiebergen-Bronkhorst, B G M; Roeleveld, M W; Jans, J J M; de Sain-van der Velden, M G M; Visser, G; van Hasselt, P M; Verhoeven-Duif, N M

    2016-09-01

    Amino acidopathies are a class of inborn errors of metabolism (IEM) that can be diagnosed by analysis of amino acids (AA) in plasma. Current strategies for AA analysis include cation exchange HPLC with post-column ninhydrin derivatization, GC-MS, and LC-MS/MS-related methods. Major drawbacks of the current methods are time-consuming procedures, derivative problems, problems with retention, and MS-sensitivity. The use of hydrophilic interaction liquid chromatography (HILIC) columns is an ideal separation mode for hydrophilic compounds like AA. Here we report a HILIC-method for analysis of 36 underivatized AA in plasma to detect defects in AA metabolism that overcomes the major drawbacks of other methods. A rapid, sensitive, and specific method was developed for the analysis of AA in plasma without derivatization using HILIC coupled with tandem mass-spectrometry (Xevo TQ, Waters). Excellent separation of 36 AA (24 quantitative/12 qualitative) in plasma was achieved on an Acquity BEH Amide column (2.1×100 mm, 1.7 μm) in a single MS run of 18 min. Plasma of patients with a known IEM in AA metabolism was analyzed and all patients were correctly identified. The reported method analyzes 36 AA in plasma within 18 min and provides baseline separation of isomeric AA such as leucine and isoleucine. No separation was obtained for isoleucine and allo-isoleucine. The method is applicable to study defects in AA metabolism in plasma.

  6. Physicochemical characterization of a new pineapple hybrid (FLHORAN41 Cv.).

    PubMed

    Brat, Pierre; Hoang, Lan Nguyen Thi; Soler, Alain; Reynes, Max; Brillouet, Jean-Marc

    2004-10-06

    The physicochemical characteristics (pH, total and soluble solids, and titratable acidity), sugars, organic acids, carotenoids, anthocyanins, volatile compounds, and cell wall polysaccharides of a new pineapple hybrid (FLHORAN41 cultivar) were measured throughout maturation and compared with the Smooth Cayenne cv. At full maturity, the FLHORAN41 cv. has a higher titratable acidity and soluble solids content than the Smooth Cayenne cv. The golden yellow flesh and red-orange to scarlet shell of ripe FLHORAN41 cv. fruits are due to carotenoid and anthocyanin levels that are, respectively, 2.5 and 1.5 times higher than those of the flesh and shell of the ripe Smooth Cayenne cv., respectively. During maturation of the FLHORAN41 cv., there was an increase in all classes of aroma compounds (mainly terpene hydrocarbons and esters), although their relative proportions were similar in both cultivars at full maturity. Cell wall polysaccharides undergo little change during maturation.

  7. Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: a multivariate study.

    PubMed

    Arain, Salma Aslam; Kazi, Tasneem G; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

    2014-12-10

    An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu(2+)) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu(2+) using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046μgL(-1) and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu(2+) in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu(2+) in serum samples of different viral hepatitis patients and healthy controls. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Lead screening in DBS by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry: application to newborns and pregnant women.

    PubMed

    Rello, Luis; Aramendía, Maite; Belarra, Miguel A; Resano, Martín

    2015-01-01

    DBS have become a clinical specimen especially adequate for establishing home-based collection protocols. In this work, high-resolution continuum source graphite furnace atomic absorption spectrometry is evaluated for the direct monitoring of Pb in DBS, both as a quantitative tool and a screening method. The development of the screening model is based on the establishment of the unreliability region around the threshold limits, 100 or 50 μg l(-1). More than 500 samples were analyzed to validate the model. The screening method demonstrated high sensitivity (the rate of true positives detected was always higher than 95%), an excellent LOD (1 µg l(-1)) and high throughput (10 min per sample).

  9. Discussion of parameters associated with the determination of arsenic by electrothermal atomic absorption spectrometry in slurried environmental samples.

    PubMed

    Vassileva, E; Baeten, H; Hoenig, M

    2001-01-02

    A slurry sampling-fast program procedure has been developed for the determination of arsenic in plants, soils and sediments by electrothermal atomic absorption spectrometry. Efficiencies of various single and mixed modifiers for thermal stabilization of arsenic and for a better removal of the matrix during pyrolysis step were compared. The influence of the slurry concentration, amounts of modifier and parameters of the pyrolysis step on the As integrated absorbance signals have been studied and a comparison between fast and conventional furnace programs was also made. The ultrasonic agitation of the slurry followed by a fast electrothermal program using an Ir/Mg modifier provides the most consistent performance in terms of precision and accuracy. The reliability of the whole procedure has been compared with results obtained after application of a wet digestion method with an HF step and validated by analyzing eleven certified reference materials. Arsenic detection and quantitation limits expressed on dry sample matter were about 30 and 100 micrograms kg-1, respectively.

  10. Mercury Pollution Exploration in Latvia with High-Sensitivity Zeeman Atomic Absorption Spectrometry

    NASA Astrophysics Data System (ADS)

    Bogans, Egils; Gavare, Zanda; Svagere, Anda; Poikane, Rita; Skudra, Jānis

    2011-01-01

    This research presents Hg pollution measurements performed in Latvia with sensitive method using Zeeman AAS analyzer RA-915+ and necessary attachments. Air in Riga city and water samples from a number of rivers and lakes of Latvia were analyzed for presence of low-level Hg concentrations. Ombrotrophic bog peat was analyzed to get insight into long-term trends. Environment in the sites sampled is relatively clean according to the results obtained, but there are local spots of pollution.

  11. Sample preparation for arsenic speciation analysis in baby food by generation of substituted arsines with atomic absorption spectrometry detection.

    PubMed

    Huber, Charles S; Vale, Maria Goreti R; Dessuy, Morgana B; Svoboda, Milan; Musil, Stanislav; Dědina, Jiři

    2017-12-01

    A slurry sampling procedure for arsenic speciation analysis in baby food by arsane generation, cryogenic trapping and detection with atomic absorption spectrometry is presented. Several procedures were tested for slurry preparation, including different reagents (HNO 3 , HCl and tetramethylammonium hydroxide - TMAH) and their concentrations, water bath heating and ultrasound-assisted agitation. The best results for inorganic arsenic (iAs) and dimethylarsinate (DMA) were reached when using 3molL -1 HCl under heating and ultrasound-assisted agitation. The developed method was applied for the analysis of five porridge powder and six baby meal samples. The trueness of the method was checked with a certified reference material (CRM) of total arsenic (tAs), iAs and DMA in rice (ERM-BC211). Arsenic recoveries (mass balance) for all samples and CRM were performed by the determination of the tAs by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted digestion and its comparison against the sum of the results from the speciation analysis. The relative limits of detection were 0.44, 0.24 and 0.16µgkg -1 for iAs, methylarsonate and DMA, respectively. The concentrations of the most toxic arsenic species (iAs) in the analyzed baby food samples ranged between 4.2 and 99µgkg -1 which were below the limits of 300, 200 and 100µgkg -1 set by the Brazilian, Chinese and European legislation, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Determination of Inorganic Arsenic in a Wide Range of Food Matrices using Hydride Generation - Atomic Absorption Spectrometry.

    PubMed

    de la Calle, Maria B; Devesa, Vicenta; Fiamegos, Yiannis; Vélez, Dinoraz

    2017-09-01

    The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to inorganic arsenic through diet, information about distribution of arsenic species in various food types must be generated. A method, previously validated in a collaborative trial, has been applied to determine inorganic arsenic in a wide variety of food matrices, covering grains, mushrooms and food of marine origin (31 samples in total). The method is based on detection by flow injection-hydride generation-atomic absorption spectrometry of the iAs selectively extracted into chloroform after digestion of the proteins with concentrated HCl. The method is characterized by a limit of quantification of 10 µg/kg dry weight, which allowed quantification of inorganic arsenic in a large amount of food matrices. Information is provided about performance scores given to results obtained with this method and which were reported by different laboratories in several proficiency tests. The percentage of satisfactory results obtained with the discussed method is higher than that of the results obtained with other analytical approaches.

  13. Investigation of Pb species in soils, celery and duckweed by synchrotron radiation X-ray absorption near-edge structure spectrometry

    NASA Astrophysics Data System (ADS)

    Luo, Liqiang; Shen, Yating; Liu, Jian; Zeng, Yuan

    2016-08-01

    The Pb species play a key role in its translocation in biogeochemical cycles. Soils, sediments and plants were collected from farmlands around Pb mines, and the Pb species in them was identified by X-ray absorption near-edge structure spectrometry. In soils, Pb5(PO4)3Cl and Pb3(PO4)2 were detected, and in sediments, Pb-fulvic acids (FAs) complex was identified. A Pb complex with FA fragments was also detected in celery samples. We found that (1) different Pb species were present in soils and sediments; (2) the Pb species in celery, which was grown in sediments, was different from the species present in duckweed, which grew in water; and (3) a Pb-FA-like compound was present in celery roots. The newly identified Pb species, the Pb-FA-like compound, may play a key role in Pb tolerance and translocation within plants.

  14. Cloud point extraction thermospray flame quartz furnace atomic absorption spectrometry for determination of ultratrace cadmium in water and urine

    NASA Astrophysics Data System (ADS)

    Wu, Peng; Zhang, Yunchang; Lv, Yi; Hou, Xiandeng

    2006-12-01

    A simple, low cost and highly sensitive method based on cloud point extraction (CPE) for separation/preconcentration and thermospray flame quartz furnace atomic absorption spectrometry was proposed for the determination of ultratrace cadmium in water and urine samples. The analytical procedure involved the formation of analyte-entrapped surfactant micelles by mixing the analyte solution with an ammonium pyrrolidinedithiocarbamate (APDC) solution and a Triton X-114 solution. When the temperature of the system was higher than the cloud point of Triton X-114, the complex of cadmium-PDC entered the surfactant-rich phase and thus separation of the analyte from the matrix was achieved. Under optimal chemical and instrumental conditions, the limit of detection was 0.04 μg/L for cadmium with a sample volume of 10 mL. The analytical results of cadmium in water and urine samples agreed well with those by ICP-MS.

  15. Use of High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS) for Sequential Multi-Element Determination of Metals in Seawater and Wastewater Samples

    NASA Astrophysics Data System (ADS)

    Peña-Vázquez, E.; Barciela-Alonso, M. C.; Pita-Calvo, C.; Domínguez-González, R.; Bermejo-Barrera, P.

    2015-09-01

    The objective of this work is to develop a method for the determination of metals in saline matrices using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Module SFS 6 for sample injection was used in the manual mode, and flame operating conditions were selected. The main absorption lines were used for all the elements, and the number of selected analytical pixels were 5 (CP±2) for Cd, Cu, Fe, Ni, Pb and Zn, and 3 pixels for Mn (CP±1). Samples were acidified (0.5% (v/v) nitric acid), and the standard addition method was used for the sequential determination of the analytes in diluted samples (1:2). The method showed good precision (RSD(%) < 4%, except for Pb (6.5%)) and good recoveries. Accuracy was checked after the analysis of an SPS-WW2 wastewater reference material diluted with synthetic seawater (dilution 1:2), showing a good agreement between certified and experimental results.

  16. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment ENVIRONMENTAL... Manufacturing Pt. 98, Subpt. AA, Table AA -2 Table AA-2 to Subpart AA of Part 98—Kraft Lime Kiln and Calciner...

  17. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40 CFR...

  18. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40 CFR...

  19. Mercury Levels in Locally Manufactured Mexican Skin-Lightening Creams

    PubMed Central

    Peregrino, Claudia P.; Moreno, Myriam V.; Miranda, Silvia V.; Rubio, Alma D.; Leal, Luz O.

    2011-01-01

    Mercury is considered one of the most toxic elements for plants and animals. Nevertheless, in the Middle East, Asia and Latin America, whitening creams containing mercury are being manufactured and purchased, despite their obvious health risks. Due to the mass distribution of these products, this can be considered a global public health issue. In Mexico, these products are widely available in pharmacies, beauty aid and health stores. They are used for their skin lightening effects. The aim of this work was to analyze the mercury content in some cosmetic whitening creams using the cold vapor technique coupled with atomic absorption spectrometry (CV-AAS). A total of 16 skin-lightening creams from the local market were investigated. No warning information was noted on the packaging. In 10 of the samples, no mercury was detected. The mercury content in six of the samples varied between 878 and 36,000 ppm, despite the fact that the U.S. Food and Drug Administration (FDA) has determined that the limit for mercury in creams should be less than 1 ppm. Skin creams containing mercury are still available and commonly used in Mexico and many developing countries, and their contents are poorly controlled. PMID:21776243

  20. AAS Statistics and the 60% Cohort

    NASA Astrophysics Data System (ADS)

    Marvel, K. B.

    2004-05-01

    I will present the latest statistics available describing the gender of the AAS membership including an update on the so-called 60% cohort (that group of AAS members from the ages of 18 to 25 who are 60% women and 40% men). The AAS membership has changed significantly in the past 30 years from an overall female membership percentage of about 10% to a level around 30% today. This trend is accelerating and indicates the ongoing inclusion of women in the physical sciences, especially astronomy. By the year 2030, the AAS membership should reach gender parity if the present trend continues.

  1. [Determination of soil exchangeable base cations by using atomic absorption spectrophotometer and extraction with ammonium acetate].

    PubMed

    Zhang, Yu-ge; Xiao, Min; Dong, Yi-hua; Jiang, Yong

    2012-08-01

    A method to determine soil exchangeable calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na) by using atomic absorption spectrophotometer (AAS) and extraction with ammonium acetate was developed. Results showed that the accuracy of exchangeable base cation data with AAS method fits well with the national standard referential soil data. The relative errors for parallel samples of exchangeable Ca and Mg with 66 pair samples ranged from 0.02%-3.14% and 0.06%-4.06%, and averaged to be 1.22% and 1.25%, respectively. The relative errors for exchangeable K and Na with AAS and flame photometer (FP) ranged from 0.06%-8.39% and 0.06-1.54, and averaged to be 3.72% and 0.56%, respectively. A case study showed that the determination method for exchangeable base cations by using AAS was proven to be reliable and trustable, which could reflect the real situation of soil cation exchange properties in farmlands.

  2. The microwave induced plasma with optical emission spectrometry (MIP-OES) in 23 elements determination in geological samples.

    PubMed

    Niedzielski, P; Kozak, L; Wachelka, M; Jakubowski, K; Wybieralska, J

    2015-01-01

    The article presents the optimisation, validation and application of the microwave induced plasma optical emission spectrometry (MIP-OES) dedicated for a routine determination of Ag, Al, B, Ba, Bi, Ca, Cd, Cr, Cu, Fe, Ga, In, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, Tl, Zn, in the geological samples. The three procedures of sample preparation has been proposed: sample digestion with the use of hydrofluoric acid for determination of total concentration of elements, extraction by aqua regia for determination of the quasi-total element concentration and extraction by hydrochloric acid solution to determine contents of the elements in acid leachable fraction. The detection limits were on the level 0.001-0.121 mg L(-1) (from 0.010-0.10 to 1.2-12 mg kg(-1) depend on the samples preparation procedure); the precision: 0.20-1.37%; accuracy 85-115% (for recovery for certified standards materials analysis and parallel analysis by independent analytical techniques: X-ray fluorescence (XRF) and flame absorption spectrometry (FAAS)). The conformity of the results obtained by MIP-OES analytical procedures with the results obtained by XRF and FAAS analysis allows to propose the procedures for studies of elemental composition of the fraction of the geological samples. Additionally, the MIP-OES technique is much less expensive than ICP techniques and much less time-consuming than AAS techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Reduced and unstratified crust in CV chondrite parent body.

    PubMed

    Ganino, Clément; Libourel, Guy

    2017-08-15

    Early Solar System planetesimal thermal models predict the heating of the chondritic protolith and the preservation of a chondritic crust on differentiated parent bodies. Petrological and geochemical analyses of chondrites have suggested that secondary alteration phases formed at low temperatures (<300 °C) by fluid-rock interaction where reduced and oxidized Vigarano type Carbonaceous (CV) chondrites witness different physicochemical conditions. From a thermodynamical survey of Ca-Fe-rich secondary phases in CV3 chondrites including silica activity (aSiO 2 ), here we show that the classical distinction between reduced and oxidized chondrites is no longer valid and that their Ca-Fe-rich secondary phases formed in similar reduced conditions near the iron-magnetite redox buffer at low aSiO 2 (log(aSiO 2 ) <-1) and moderate temperature (210-610 °C). The various lithologies in CV3 chondrites are inferred to be fragments of an asteroid percolated heterogeneously via porous flow of hydrothermal fluid. Putative 'onion shell' structures are not anymore a requirement for the CV parent body crust.Meteorites may unlock the history of the early solar system. Here, the authors find, through Ca-Fe-rich secondary phases, that the distinction between reduced and oxidized CV chondrites is invalid; therefore, CV3 chondrites are asteroid fragments that percolated heterogeneously via porous flow of hydrothermal fluid.

  4. Activity of vegetative insecticidal proteins Vip3Aa58 and Vip3Aa59 of Bacillus thuringiensis against lepidopteran pests.

    PubMed

    Baranek, Jakub; Kaznowski, Adam; Konecka, Edyta; Naimov, Samir

    2015-09-01

    Vegetative insecticidal proteins (Vips) secreted by some isolates of Bacillus thuringiensis show activity against insects and are regarded as insecticides against pests. A number of B. thuringiensis strains harbouring vip3A genes were isolated from different sources and identified by using a PCR based approach. The isolates with the highest insecticidal activity were indicated in screening tests, and their vip genes were cloned and sequenced. The analysis revealed two polymorphic Vip protein forms, which were classified as Vip3Aa58 and Vip3Aa59. After expression of the vip genes, the proteins were isolated and characterized. The activity of both toxins was estimated against economically important lepidopteran pests of woodlands (Dendrolimus pini), orchards (Cydia pomonella) and field crops (Spodoptera exigua). Vip3Aa58 and Vip3Aa59 were highly toxic and their potency surpassed those of many Cry proteins used in commercial bioinsecticides. Vip3Aa59 revealed similar larvicidal activity as Vip3Aa58 against S. exigua and C. pomonella. Despite 98% similarity of amino acid sequences of both proteins, Vip3Aa59 was significantly more active against D. pini. Additionally the effect of proteolytic activation of Vip58Aa and Vip3Aa59 on toxicity of D. pini and S. exigua was studied. Both Vip3Aa proteins did not show any activity against Tenebrio molitor (Coleoptera) larvae. The results suggest that the Vip3Aa58 and Vip3Aa59 toxins might be useful for controlling populations of insect pests of crops and forests. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Speciation of organic and inorganic selenium in selenium-enriched rice by graphite furnace atomic absorption spectrometry after cloud point extraction.

    PubMed

    Sun, Mei; Liu, Guijian; Wu, Qianghua

    2013-11-01

    A new method was developed for the determination of organic and inorganic selenium in selenium-enriched rice by graphite furnace atomic absorption spectrometry detection after cloud point extraction. Effective separation of organic and inorganic selenium in selenium-enriched rice was achieved by sequentially extracting with water and cyclohexane. Under the optimised conditions, the limit of detection (LOD) was 0.08 μg L(-1), the relative standard deviation (RSD) was 2.1% (c=10.0 μg L(-1), n=11), and the enrichment factor for selenium was 82. Recoveries of inorganic selenium in the selenium-enriched rice samples were between 90.3% and 106.0%. The proposed method was successfully applied for the determination of organic and inorganic selenium as well as total selenium in selenium-enriched rice. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. The first mass and angular momentum loss measurements for a CV-like binary

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy

    2015-10-01

    The period distribution of close binaries, cataclysmic variables, novae and single-degenerate SN1a progenitor candidates is largely controlled by magnetically-driven mass and angular momentum loss (AML) from the M dwarf secondary. The mass loss rates for these spun-up stars remain essentially unknown and impossible to observe directly, with likely values in the range 1e-12 to 1e-15 Msun/yr. AML presciptions for CVs differ by orders of magnitude. One way to measure the mass loss rate is to observe the dM wind accrete onto its WD companion in a pre-CV very close to Roche Lobe overflow but lacking the obscuring complications and emission from an accretion disk. The measurement can be combined with realistic MHD models to understand the accretion fraction, the mass that escapes, and the AML. The best-studied nearby pre-CV is QS Vir (48pc, P=3.6hr). However, its wind accretion rates measured from 1999 HST UV spectra of the WD metal absorption lines and 2006 XMM-Newton CCD spectroscopy differ by a factor of a thousand, pointing to either a dominant CME stochastic component, or a magnetic switch found in MHD simulations and driven by cyclic activity on the M dwarf. HST COS spectra combined with XMM-Newton monitoring on timescales from weeks to years will tease out CME vs cyclic accretion variations. UV and X-ray measurements will provide the first consistency check of both accretion rate measurement methods. MHD models tailored to the system will enable the first quasi-direct measurements of the mass loss and AML from a CV-like binary. Our project requires 6 HST/COS orbits in Cycles 22-24, and 60ksec on XMM in Cycle 22

  7. The first mass and angular momentum loss measurements for a CV-like binary

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy

    2014-10-01

    The period distribution of close binaries, cataclysmic variables, novae and single-degenerate SN1a progenitor candidates is largely controlled by magnetically-driven mass and angular momentum loss (AML) from the M dwarf secondary. The mass loss rates for these spun-up stars remain essentially unknown and impossible to observe directly, with likely values in the range 1e-12 to 1e-15 Msun/yr. AML presciptions for CVs differ by orders of magnitude. One way to measure the mass loss rate is to observe the dM wind accrete onto its WD companion in a pre-CV very close to Roche Lobe overflow but lacking the obscuring complications and emission from an accretion disk. The measurement can be combined with realistic MHD models to understand the accretion fraction, the mass that escapes, and the AML. The best-studied nearby pre-CV is QS Vir (48pc, P=3.6hr). However, its wind accretion rates measured from 1999 HST UV spectra of the WD metal absorption lines and 2006 XMM-Newton CCD spectroscopy differ by a factor of a thousand, pointing to either a dominant CME stochastic component, or a "magnetic switch" found in MHD simulations and driven by cyclic activity on the M dwarf. HST COS spectra combined with XMM-Newton monitoring on timescales from weeks to years will tease out CME vs cyclic accretion variations. UV and X-ray measurements will provide the first consistency check of both accretion rate measurement methods. MHD models tailored to the system will enable the first quasi-direct measurements of the mass loss and AML from a CV-like binary. Our project requires 6 HST/COS orbits in Cycles 22-24, and 60ksec on XMM in Cycle 22

  8. The first mass and angular momentum loss measurements for a CV-like binary

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy

    2016-10-01

    The period distribution of close binaries, cataclysmic variables, novae and single-degenerate SN1a progenitor candidates is largely controlled by magnetically-driven mass and angular momentum loss (AML) from the M dwarf secondary. The mass loss rates for these spun-up stars remain essentially unknown and impossible to observe directly, with likely values in the range 1e-12 to 1e-15 Msun/yr. AML presciptions for CVs differ by orders of magnitude. One way to measure the mass loss rate is to observe the dM wind accrete onto its WD companion in a pre-CV very close to Roche Lobe overflow but lacking the obscuring complications and emission from an accretion disk. The measurement can be combined with realistic MHD models to understand the accretion fraction, the mass that escapes, and the AML. The best-studied nearby pre-CV is QS Vir (48pc, P=3.6hr). However, its wind accretion rates measured from 1999 HST UV spectra of the WD metal absorption lines and 2006 XMM-Newton CCD spectroscopy differ by a factor of a thousand, pointing to either a dominant CME stochastic component, or a magnetic switch found in MHD simulations and driven by cyclic activity on the M dwarf. HST COS spectra combined with XMM-Newton monitoring on timescales from weeks to years will tease out CME vs cyclic accretion variations. UV and X-ray measurements will provide the first consistency check of both accretion rate measurement methods. MHD models tailored to the system will enable the first quasi-direct measurements of the mass loss and AML from a CV-like binary. Our project requires 6 HST/COS orbits in Cycles 22-24, and 60ksec on XMM in Cycle 22

  9. Rapid food decomposition by H2O2-H2SO4 for determination of total mercury by flow injection cold vapor atomic absorption spectrometry.

    PubMed

    Zenebon, Odair; Sakuma, Alice M; Dovidauskas, Sergio; Okada, Isaura A; de, MaioFrancaD; Lichtig, Jaim

    2002-01-01

    A mixture of 50% H2O2-H2SO4 (3 + 1, v/v) was used for decomposition of food in open vessels at 80 degrees C. The treatment allowed rapid total mercury determination by flow injection cold vapor atomic absorption spectrometry. Cabbage, potatoes, peanuts paste, hazelnuts paste, oats, tomatoes and their derivatives, oysters, shrimps, prawns, shellfish, marine algae, and many kinds of fish were analyzed by the proposed methodology with a limit of quantitation of 0.86 +/- 0.08 microg/L mercury in the final solution. Reference materials tested also gave excellent recovery.

  10. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF THE PERKIN-ELMER ZEEMAN/5000 SYSTEM ATOMIC ABSORPTION SPECTROMETER (BCO-L-6.0)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5000 atomic absorption spectrophotometer (PE 5000 AA), and the Perkin Elmer 5000 Zeeman graphite furnace atomic absorption spectrophotometer (PE 5000Z GFAA)...

  11. The determination of lead in sugar and sweets without digestion by electrothermal atomic absorption spectrometry (ETAAS) with a rhodium chemical modifier.

    PubMed

    Dias, V M C; Cardoso, A S B

    2006-05-01

    Reference methods for determining lead in food are usually time-consuming. This paper reports a straightforward procedure using electrothermal atomic absorption spectrometry (ETAAS), to determine lead (Pb) in fat-free sweets. Several chemical modifiers were examined and results showed that it is not necessary to digest the samples, when a rhodium (Rh) modifier was used. The samples were dissolved in nitric acid and the determination of Pb was performed by ETAAS, using Rh chemical modifier at a pyrolysis temperature of 900 degrees C and an atomization temperature of 1,500 degrees C. No ashing step was employed and aqueous standards were used, in the range 2-10 microg l(-1). The limit of quantification was 0.095 mg kg(-1), and the accuracy of the method was verified by analysing certified reference materials.

  12. On-line preconcentration system for lead(II) determination in waste water by atomic absorption spectrometry using active carbon loaded with Pyrogallol Red.

    PubMed

    Ensafi, Ali A; Khayamian, Taghi; Karbasi, Mohammad H

    2003-06-01

    An on-line system for enrichment and determination of lead(II) is presented. It is based on the adsorption of lead(II) ions on a minicolumn packed with active carbon loaded with Pyrogallol Red. After preconcentration step, the metal ions are eluted automatically by 5.0 ml of 0.50 M nitric acid solution and the lead ion contents were determined by atomic absorption spectrometry. The influence of chemicals, pH and flow variables were studied as well as effect of potential interfering ions. Under the optimum conditions, the lead ions in aqueous samples were concentrated about 100 fold by the column. The detection limit was 0.001 microg ml(-1). The recovery percent of spliced lead(II) was in the range of 98%-103%.

  13. Atomic absorption spectrophotometric determination of tin in canned foods, using nitric acid-hydrochloric acid digestion and nitrous oxide-acetylene flame: collaborative study.

    PubMed

    Dabeka, R W; McKenzie, A D; Albert, R H

    1985-01-01

    Twenty-six collaborators participated in a study to evaluate an atomic absorption spectrophotometric (AAS) method for the determination of tin in canned foods. The 5 foods evaluated were meat, pineapple juice, tomato paste, evaporated milk, and green beans, each spiked at 2 levels. The concentration range of tin in the samples was 10-450 micrograms/g, and each level was sent as a blind duplicate. Statistical treatment of results revealed no laboratory outliers and 6 individual or replicate-total outliers, accounting for 3.3% of the data. Repeatability (within-laboratory) coefficient of variation (CVo) ranged from 2.2 to 48%, depending on the tin level and food evaluated. For samples containing greater than or equal to 80 micrograms/g of tin, repeatability CV averaged 5.6% including outliers and 3.7% after their rejection. Overall among-laboratories coefficient of variation (CVx) varied from 3.3 to 58%; at levels greater than or equal to 80 micrograms/g, it averaged 7.3% with outliers and 5.3% after their rejection. Recovery of tin, based on spiking levels, ranged from 100.0 to 112.8% and averaged 105.4%. Detection limit range is 2-10 micrograms/g, and lower quantitation limit is 40 micrograms/g. This method has been adopted official first action.

  14. Development and Validation of a Sensitive Method for Trace Nickel Determination by Slotted Quartz Tube Flame Atomic Absorption Spectrometry After Dispersive Liquid-Liquid Microextraction.

    PubMed

    Yolcu, Şükran Melda; Fırat, Merve; Chormey, Dotse Selali; Büyükpınar, Çağdaş; Turak, Fatma; Bakırdere, Sezgin

    2018-05-01

    In this study, dispersive liquid-liquid microextraction was systematically optimized for the preconcentration of nickel after forming a complex with diphenylcarbazone. The measurement output of the flame atomic absorption spectrometer was further enhanced by fitting a custom-cut slotted quartz tube to the flame burner head. The extraction method increased the amount of nickel reaching the flame and the slotted quartz tube increased the residence time of nickel atoms in the flame to record higher absorbance. Two methods combined to give about 90 fold enhancement in sensitivity over the conventional flame atomic absorption spectrometry. The optimized method was applicable over a wide linear concentration range, and it gave a detection limit of 2.1 µg L -1 . Low relative standard deviations at the lowest concentration in the linear calibration plot indicated high precision for both extraction process and instrumental measurements. A coal fly ash standard reference material (SRM 1633c) was used to determine the accuracy of the method, and experimented results were compatible with the certified value. Spiked recovery tests were also used to validate the applicability of the method.

  15. Core Microbiota and Metabolome of Vitis vinifera L. cv. Corvina Grapes and Musts

    PubMed Central

    Stefanini, Irene; Carlin, Silvia; Tocci, Noemi; Albanese, Davide; Donati, Claudio; Franceschi, Pietro; Paris, Michele; Zenato, Alberto; Tempesta, Silvano; Bronzato, Alberto; Vrhovsek, Urska; Mattivi, Fulvio; Cavalieri, Duccio

    2017-01-01

    The composition and changes of the fungal population and of the metabolites present in grapes and in ferments of Vitis vinifera L. cv. Corvina, one of the major components of the Amarone musts, were dissected aiming at the identification of constant characteristics possibly influenced by the productive process. The fungal populations and metabolomic profiles were analyzed in three different vintages. 454-pyrosequencing on the ribosomal ITS1 region has been used to identify the fungal population present in Corvina grapes and fresh must. Samples were also subjected to metabolomics analysis measuring both free volatile compounds and glycosylated aroma precursors through an untargeted approach with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. Albeit strongly dependent on the climate, both the mycobiota and metabolome of Corvina grapes and fresh musts show some characteristics recursive in different vintages. Such persistent characteristics are likely determined by the method adopted to produce Amarone or other dry wines made from partially dried grapes. In particular, the harsh conditions imposed by the prolonged withering appear to contribute to the shaping of the fungal populations. The fungal genera and metabolites present in different vintages in V. vinifera L. cv. Corvina grapes and fresh musts represent core components of the peculiar technique of production of Amarone. Their identification allows the in-depth understanding and improved control of the process of production of this economically and culturally relevant wine. PMID:28377754

  16. Co-expression of AaPMT and AaTRI effectively enhances the yields of tropane alkaloids in Anisodus acutangulus hairy roots

    PubMed Central

    2011-01-01

    Background Tropane alkaloids (TA) including anisodamine, anisodine, hyoscyamine and scopolamine are a group of important anticholinergic drugs with rapidly increasing market demand, so it is significant to improve TA production by biotechnological approaches. Putrescine N-methyltransferase (PMT) was considered as the first rate-limiting upstream enzyme while tropinone reductase I (TRI) was an important branch-controlling enzyme involved in TA biosynthesis. However, there is no report on simultaneous introduction of PMT and TRI genes into any TA-producing plant including Anisodus acutangulus (A. acutangulus), which is a Solanaceous perennial plant that is endemic to China and is an attractive resource plant for production of TA. Results In this study, 21 AaPMT and AaTRI double gene transformed lines (PT lines), 9 AaPMT single gene transformed lines (P lines) and 5 AaTRI single gene transformed lines (T lines) were generated. RT-PCR and real-time fluorescence quantitative analysis results revealed that total AaPMT (AaPMT T) and total AaTRI (AaTRI T) gene transcripts in transgenic PT, P and T lines showed higher expression levels than native AaPMT (AaPMT E) and AaTRI (AaTRI E) gene transcripts. As compared to the control and single gene transformed lines (P or T lines), PT transgenic hairy root lines produced significantly higher levels of TA. The highest yield of TA was detected as 8.104 mg/g dw in line PT18, which was 8.66, 4.04, and 3.11-times higher than those of the control (0.935 mg/g dw), P3 (highest in P lines, 2.004 mg/g dw) and T12 (highest in T lines, 2.604 mg/g dw), respectively. All the tested samples were found to possess strong radical scavenging capacity, which were similar to control. Conclusion In the present study, the co-expression of AaPMT and AaTRI genes in A. acutangulus hairy roots significantly improved the yields of TA and showed higher antioxidant activity than control because of higher total TA content, which is the first report on

  17. High-throughput quantification of the levels and labeling abundance of free amino acids by liquid chromatography tandem mass spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cocuron, Jean-Christophe; Tsogtbaatar, Enkhtuul; Alonso, Ana P.

    Accurate assessment of mass isotopomer distributions (MIDs) of intracellular metabolites, such as free amino acids (AAs), is crucial for quantifying in vivo fluxes. To date, the majority of studies that measured AA MIDs have relied on the analysis of proteinogenic rather than free AAs by: i) GC–MS, which involved cumbersome process of derivatization, or ii) NMR, which requires large quantities of biological sample. In this work, the development and validation of a high-throughput LC–MS/MS method allowing the quantification of the levels and labeling of free AAs is described. Sensitivity in the order of the femtomol was achieved using multiple reactionmore » monitoring mode (MRM). The MIDs of all free AAs were assessed without the need of derivatization, and were validated (except for Trp) on a mixture of unlabeled AA standards. Finally, this method was applied to the determination of the 13C-labeling abundance in free AAs extracted from maize embryos cultured with 13C-glutamine or 13C-glucose. Although Cys was below the limit of detection in these biological samples, the MIDs of a total of 18 free AAs were successfully determined. Due to the increased application of tandem mass spectrometry for 13C-Metabolic Flux Analysis, this novel method will enable the assessment of more complete and accurate labeling information of intracellular AAs, and therefore a better definition of the fluxes.« less

  18. High-throughput quantification of the levels and labeling abundance of free amino acids by liquid chromatography tandem mass spectrometry

    DOE PAGES

    Cocuron, Jean-Christophe; Tsogtbaatar, Enkhtuul; Alonso, Ana P.

    2017-02-16

    Accurate assessment of mass isotopomer distributions (MIDs) of intracellular metabolites, such as free amino acids (AAs), is crucial for quantifying in vivo fluxes. To date, the majority of studies that measured AA MIDs have relied on the analysis of proteinogenic rather than free AAs by: i) GC–MS, which involved cumbersome process of derivatization, or ii) NMR, which requires large quantities of biological sample. In this work, the development and validation of a high-throughput LC–MS/MS method allowing the quantification of the levels and labeling of free AAs is described. Sensitivity in the order of the femtomol was achieved using multiple reactionmore » monitoring mode (MRM). The MIDs of all free AAs were assessed without the need of derivatization, and were validated (except for Trp) on a mixture of unlabeled AA standards. Finally, this method was applied to the determination of the 13C-labeling abundance in free AAs extracted from maize embryos cultured with 13C-glutamine or 13C-glucose. Although Cys was below the limit of detection in these biological samples, the MIDs of a total of 18 free AAs were successfully determined. Due to the increased application of tandem mass spectrometry for 13C-Metabolic Flux Analysis, this novel method will enable the assessment of more complete and accurate labeling information of intracellular AAs, and therefore a better definition of the fluxes.« less

  19. A study of aerosol absorption and height retrievals with a hyperspectral (UV to NIR) passive sensor

    NASA Astrophysics Data System (ADS)

    Gasso, S.

    2017-12-01

    With the deployment of the first sensor (TOMS, in 1978) with capabilities to detect aerosol absorption (AA) from space, there has been a continuous evolution in hardware and algorithms used to measured this property. Although with TOMS and its more advanced successors (such as OMI) made significant progress in globally characterizing AA , there is room for improvement especially by taking advantage of sensors with extended spectral coverage (UV to NIR) and high spatial resolution (<1 km). While such unique sensor does not exist yet, the collocation of observations from different platforms that jointly fulfill those characteristics (e.g. A-Train, S-NPP) confirm that it is possible to fully retrieve all AA parameters that modulate absorption in the upwelling radiance (AOD, SSA and aerosol layer height). However, such combined approaches still have some drawbacks such as the difficulty to account for cloud contamination. The upcoming deployment of satellite detectors with the desired features all in one sensor (PACE, TropOMI, GEMS) prompt a revision of the AA retrieval technique used in past approaches. In particular,the TropOMI mission, a hyperspectral UV-to-NIR sensor with moderate ( 5km nadir pixel) spatial resolution to be launched in Fall 2017. In addition , the sensor will include sensing capabilities for the wavelength range of the Oxygen bands A and B at very high wavelength resolution. This study will be centered on the aerosol detection capabilities of TropOMI. Because the spectral range covered, it is theoretically possible to simultaneously retrieve the aerosol optical depth, the single scattering albedo and aerosol mean height without assuming any of them as it was the case with previous retrieval approaches. Specifically, we intend to present a theoretical study based on simulated radiances at selected UV, VIS and near-IR bands (including the Oxygen bands) and evaluate the sensitivity of this sensor to different levels of aerosol concentration, height

  20. Simultaneous preconcentration of cadmium and lead in water samples with silica gel and determination by flame atomic absorption spectrometry.

    PubMed

    Xu, Hongbo; Wu, Yun; Wang, Jian; Shang, Xuewei; Jiang, Xiaojun

    2013-12-01

    A new method that utilizes pretreated silica gel as an adsorbent has been developed for simultaneous preconcentration of trace Cd(II) and Pb(II) prior to the measurement by flame atomic absorption spectrometry. The effects of pH, the shaking time, the elution condition and the coexisting ions on the separation/preconcentration conditions of analytes were investigated. Under optimized conditions, the static adsorption capacity of Cd(II) and Pb(II) were 45.5 and 27.1mg/g, the relative standard deviations were 3.2% and 1.7% (for n = 11), and the limits of detection obtained were 4.25 and 0.60 ng/mL, respectively. The method was validated by analyzing the certified reference materials GBW 07304a (stream sediment) and successfully applied to the analysis of various treated wastewater samples with satisfactory results. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  1. CaI and SrI molecules for iodine determination by high-resolution continuum source graphite furnace molecular absorption spectrometry: Greener molecules for practical application.

    PubMed

    Zanatta, Melina Borges Teixeira; Nakadi, Flávio Venâncio; da Veiga, Márcia Andreia Mesquita Silva

    2018-03-01

    A new method to determine iodine in drug samples by high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) has been developed. The method measures the molecular absorption of a diatomic molecule, CaI or SrI (less toxic molecule-forming reagents), at 638.904 or 677.692nm, respectively, and uses a mixture containing 5μg of Pd and 0.5μg of Mg as chemical modifier. The method employs pyrolysis temperatures of 1000 and 800°C and vaporization temperatures of 2300 and 2400°C for CaI and SrI, respectively. The optimized amounts of Ca and Sr as molecule-forming reagents are 100 and 150µg, respectively. On the basis of interference studies, even small chlorine concentrations reduce CaI and SrI absorbance significantly. The developed method was used to analyze different commercial drug samples, namely thyroid hormone pills with three different iodine amounts (15.88, 31.77, and 47.66µg) and one liquid drug with 1% m v -1 active iodine in their compositions. The results agreed with the values informed by the manufacturers (95% confidence level) regardless of whether CaI or SrI was determined. Therefore, the developed method is useful for iodine determination on the basis of CaI or SrI molecular absorption. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Microstructural features of friction stir welded dissimilar Aluminium alloys AA2219-AA7475

    NASA Astrophysics Data System (ADS)

    Zaman Khan, Noor; Ubaid, Mohammed; Siddiquee, Arshad Noor; Khan, Zahid A.; Al-Ahmari, Abdulrahman; Chen, Xizhang; Haider Abidi, Mustufa

    2018-05-01

    High strength, good corrosion resistance, light weight make aluminium alloys a material of choice in many industrial sectors like aerospace, marine etc. Problems associated with welding of these alloys by fusion welding processes restricted their use in various industries. Friction stir welding (FSW), a clean solid-state joining process, easily overcomes various difficulties encountered during conventional fusion welding processes. In the present work, the effect of rotational speed (710 rpm, 900 rpm and 1120 rpm) on micro-hardness distribution and microstructure of FSWed dissimilar aluminium alloy joints were analyzed. Plates of AA7475-T761 and AA2219-O having thickness of 2.5 mm were welded by fixing AA7475 on retreating side (RS) and AA2219 on advancing side (AS). Welded joints were characterized by Vickers micro-hardness testing, scanning electron microscopy (SEM) and optical microscopy (OM). Results revealed that rotational speed significantly affects the micro-hardness due to increase in grain size, coarsening and dissolution of strengthening precipitates and re-precipitation. Higher micro-hardness values were observed in stir zone due to grain refinement and re-precipitation. Minimum micro-hardness value was observed at the TMAZ/HAZ of advancing side due to thermal softening.

  3. Environmental modulation of autoimmune arthritis involves the spontaneous microbial induction of T cell responses to regulatory determinants within heat shock protein 65.

    PubMed

    Moudgil, K D; Kim, E; Yun, O J; Chi, H H; Brahn, E; Sercarz, E E

    2001-03-15

    Both genetic and environmental factors are believed to be involved in the induction of autoimmune diseases. Adjuvant arthritis (AA) is inducible in susceptible rat strains by injection of Mycobacterium tuberculosis, and arthritic rats raise T cell responses to the 65-kDa mycobacterial heat-shock protein (Bhsp65). We observed that Fischer 344 (F344) rats raised in a barrier facility (BF-F344) are susceptible to AA, whereas F344 rats maintained in a conventional facility (CV-F344) show significantly reduced incidence and severity of AA, despite responding well to the arthritogenic determinant within Bhsp65. The acquisition of protection from AA can be circumvented if rats are maintained on neomycin/acidified water. Strikingly, naive unimmunized CV-F344 rats but not BF-F344 rats raised T cell responses to Bhsp65 C-terminal determinants (BCTD) (we have previously shown that BCTD are involved in regulation of acute AA in the Lewis rat); however, T cells of naive CV-F344 and BF-F344 gave a comparable level of proliferative response to a mitogen, but no response at all to an irrelevant Ag. Furthermore, adoptive transfer into naive BF-F344 rats of splenic cells of naive CV-F344 rats (restimulated with BCTD in vitro) before induction of AA resulted in a considerably reduced severity of AA. These results suggest that spontaneous (inadvertent) priming of BCTD-reactive T cells, owing to determinant mimicry between Bhsp65 and its homologues in microbial agents in the conventional environment, is involved in modulating the severity of AA in CV-F344 rats. These results have important implications in broadening understanding of the host-microbe interaction in human autoimmune diseases.

  4. Antibacterial and cytotoxic activity of isoprenylated coumarin mammea A/AA isolated from Mammea africana.

    PubMed

    Canning, Corene; Sun, Shi; Ji, Xiangming; Gupta, Smiti; Zhou, Kequan

    2013-05-02

    The stem bark of Mammea africana is widely distributed in tropical Africa and commonly used in traditional medicine. This study aims to identify the active compound in Mammea africana and to evaluate its antimicrobial and antiproliferative activity. Methanol extract from the bark of the Mammea africana was separated by liquid-liquid extraction, followed by open column chromatography. A principal antimicrobial compound was purified by high performance liquid chromatography (HPLC) and its structure was elucidated by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). The antibacterial activity of the purified compound was determined using the broth microdilution method against 7 common pathogenic bacteria. The compound was also evaluated for cytotoxicity by cell proliferation assay (MTS) using the mouse embryonic fibroblast cell line NIH 3T3 and the non-small cell lung cancer cell line A549. The purified active compound was determined to be mammea A/AA and was found to be highly active against Campylobacter jejuni (MIC=0.5 μg/ml), Streptococcus pneumoniae (MIC=0.25 μg/ml), and Clostridium difficile (MIC=0.25 μg/ml). The compound exhibited significant antiproliferative activities against both NIH 3T3 and A549 cell lines. Mammea A/AA isolated from Mammea africana exerts specific inhibitory activity against Campylobacter jejuni, Streptococcus pneumoniae, and Campylobacter difficile. Mammea A/AA was also found to exhibit significant cytotoxicity against both cancer and normal cell lines. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  5. Experimental transmission of AA amyloidosis by injecting the AA amyloid protein into interleukin-1 receptor antagonist knockout (IL-1raKO) mice.

    PubMed

    Watanabe, K; Uchida, K; Chambers, J K; Tei, M; Shoji, A; Ushio, N; Nakayama, H

    2015-05-01

    The incidence of AA amyloidosis is high in humans with rheumatoid arthritis and several animal species, including cats and cattle with prolonged inflammation. AA amyloidosis can be experimentally induced in mice using severe inflammatory stimuli and a coinjection of AA amyloid; however, difficulties have been associated with transmitting AA amyloidosis to a different animal species, and this has been attributed to the "species barrier." The interleukin-1 receptor antagonist knockout (IL-1raKO) mouse, a rodent model of human rheumatoid arthritis, has been used in the transmission of AA amyloid. When IL-1raKO and BALB/c mice were intraperitoneally injected with mouse AA amyloid together with a subcutaneous pretreatment of 2% AgNO3, all mice from both strains that were injected with crude or purified murine AA amyloid developed AA amyloidosis. However, the amyloid index, which was determined by the intensity of AA amyloid deposition, was significantly higher in IL-1raKO mice than in BALB/c mice. When IL-1raKO and BALB/c mice were injected with crude or purified bovine AA amyloid together with the pretreatment, 83% (5/6 cases) and 38% (3/8 cases) of IL-1raKO mice and 17% (1/6 cases) and 0% (0/6 cases) of BALB/c mice, respectively, developed AA amyloidosis. Similarly, when IL-1raKO and BALB/c mice were injected with crude or purified feline AA amyloid, 33% (2/6 cases) and 88% (7/8 cases) of IL-1raKO mice and 0% (0/6 cases) and 29% (2/6 cases) of BALB/c mice, respectively, developed AA amyloidosis. These results indicated that IL-1raKO mice are a useful animal model for investigating AA amyloidogenesis. © The Author(s) 2014.

  6. Solvent microextraction-flame atomic absorption spectrometry (SME-FAAS) for determination of ultratrace amounts of cadmium in meat and fish samples.

    PubMed

    Goudarzi, Nasser

    2009-02-11

    A simple, low cost and highly sensitive method based on solvent microextraction (SME) for separation/preconcentration and flame atomic absorption spectrometry (FAAS) was proposed for the determination of ultratrace amounts of cadmium in meat and fish samples. The analytical procedure involved the formation of a hydrophobic complex by mixing the analyte solution with an ammonium pyrrolidinedithiocarbamate (APDC) solution. In suitable conditions, the complex of cadmium-APDC entered the micro organic phase, and thus, separation of the analyte from the matrix was achieved. Under optimal chemical and instrumental conditions, a detection limit (3 sigma) of 0.8 ng L(-1) and an enrichment factor of 93 were achieved. The relative standard deviation for the method was found to be 2.2% for Cd. The interference effects of some anions and cations were also investigated. The developed method has been applied to the determination of trace Cd in meat and fish samples.

  7. Technical aspects of neonatal screening using tandem mass spectrometry. Report from the 4th meeting of the International Society for Neonatal Screening.

    PubMed

    Simonsen, H; Jensen, U G

    1999-12-01

    Quantitative analysis of amino acids (AA) and acylcarnitines using tandem mass spectrometry is an emerging technology used to screen neonatal dried blood spot samples for disorders in the metabolism of AA, organic acids and fatty acids. This paper provides a brief review of some of the technically oriented issues which emerged at the 4th meeting of the International Society for Neonatal Screening in Stockholm, 1999. The information covers sample preparation, instrumentation, data acquistion modes, internal standards, interpretation, confounding factors and practical screening experience.

  8. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  9. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  10. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  11. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  12. [Determination of metals in waste bag filter of steel works by microwave digestion-flame atomic absorption spectrometry].

    PubMed

    Ning, Xun-An; Zhou, Yun; Liu, Jing-Yong; Wang, Jiang-Hui; Li, Lei; Ma, Xiao-Guo

    2011-09-01

    A method of microwave digestion technique-flame atomic absorption spectrometry was proposed to determine the total contents of Cu, Zn, Pb, Cd, Cr and Ni in five different kinds of waste bag filters from a steel plant. The digestion effects of the six acid systems on the heavy metals digestion were studied for the first time. The relative standard deviation (RSD) of the method was between 1.02% and 9.35%, and the recovery rates obtained by standard addition method ranged from 87.7% to 105.6%. The results indicated that the proposed method exhibited the advantages of simplicity, speediness, accuracy and repeatability, and it was suitable for determining the metal elements of the waste bag filter. The results also showed that different digestion systems should be used according to different waste bag filters. The waste bag filter samples from different production processes had different metal elements content. The Pb and Zn were the highest in the waste bag filters, while the Cu, Ni, Cd and Cr were relatively lower. These determination results provided the scientific data for further treatment and disposal of the waste bag filter.

  13. Preconcentration of lead using solidification of floating organic drop and its determination by electrothermal atomic absorption spectrometry

    PubMed Central

    Chamsaz, Mahmoud; Akhoundzadeh, Jeiran; Arbab-zavar, Mohammad Hossein

    2012-01-01

    A simple microextraction method based on solidification of a floating organic drop (SFOD) was developed for preconcentration of lead prior to its determination by electrothermal atomic absorption spectrometry (ETAAS). Ammonium pyrolidinedithiocarbamate (APDC) was used as complexing agent, and the formed complex was extracted into a 20 μL of 1-undecanol. The extracted complex was diluted with ethanol and injected into a graphite furnace. An orthogonal array design (OAD) with OA16 (45) matrix was employed to study the effects of different parameters such as pH, APDC concentration, stirring rate, sample solution temperature and the exposure time on the extraction efficiency. Under the optimized experimental conditions the limit of detection (based on 3 s) and the enhancement factor were 0.058 μg L−1 and 113, respectively. The relative standard deviation (RSD) for 8 replicate determinations of 1 μg L−1 of Pb was 8.8%. The developed method was validated by the analysis of certified reference materials and was successfully applied to the determination of lead in water and infant formula base powder samples. PMID:25685441

  14. Use of atomic absorption spectrometry in assessment of biomonitor plants for lead, cadmium and copper pollution.

    PubMed

    Gokce, Kaya; Mehmet, Yaman

    2012-01-01

    Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep, Turkey. Lead, cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption spectrometry. Lead, Cd and Cu concentrations in the soil samples taken from battery area were found to be in the ranges of 304-602, 0.4-0.44 and 31-37 mg x kg(-1), respectively. Significantly increased lead concentration up to 2 750 mg x kg(-1) was found in the leaves of Eleagnus angustifolia L. plant. The lead concentrations in the other plant leaves taken from 50 m around battery factory followed the order Ailanthus altissima > Morus sp. > Juglans regia L. > Ficus carica L. > Cydonia oblonga Miller > Prunus x domestica L. The plants, Populus nigra L. , Eleagnus angustifolia L. and Salix sp. were found useful for Cd, and the plant, Eleagnus angusti folia L. for Pb, to be considered as potential biomonitor. Especially, leaves of trees and plants taken from the distance of 50 m from battery plant have relatively higher Pb concentrations. Therefore, people who and animals which live in this area and benefit from these soil and plants have vital risks.

  15. Qualitative and Quantitative Content Determination of Macro-Minor Elements in Bryonia Alba L. Roots using Flame Atomic Absorption Spectroscopy Technique.

    PubMed

    Karpiuk, Uliana Vladimirovna; Al Azzam, Khaldun Mohammad; Abudayeh, Zead Helmi Mahmoud; Kislichenko, Viktoria; Naddaf, Ahmad; Cholak, Irina; Yemelianova, Oksana

    2016-06-01

    To determine the elements in Bryonia alba L. roots, collected from the Crimean Peninsula region in Ukraine. Dry ashing was used as a flexible method and all elements were determined using atomic absorption spectrometry (AAS) equipped with flame and graphite furnace. The average concentrations of the determined elements, expressed as mg/100 g dry weight of the sample, were as follow: 13.000 for Fe, 78.000 for Si, 88.000 for P, 7.800 for Al, 0.130 for Mn, 105.000 for Mg, 0.030 for Pb, 0.052 for Ni, 0.030 for Mo, 210.000 for Ca, 0.130 for Cu, 5.200 for Zn, 13.000 for Na, 1170.000 for K, 0.780 for Sr, 0.030 for Co, 0.010 for Cd, 0.010 for As, and 0.010 for Hg. Toxic elements such as Cd and Pb were also found but at very low concentration. Among the analyzed elements, K was the most abundant followed by Ca, Mg, P, Si, Fe, Na, and Zn, whereas Hg, As, Cd, Co, Mo, and Pb were found in low concentration. The results suggest that the roots of Bryonia alba L. plant has potential medicinal property through their high element contents present. Moreover, it showed that the AAS method is a simple, fast, and reliable for the determination of elements in plant materials. The obtained results of the current study provide justification for the usage of such fruit in daily diet for nutrition and for medicinal usage in the treatment of various diseases.

  16. Qualitative and Quantitative Content Determination of Macro-Minor Elements in Bryonia Alba L. Roots using Flame Atomic Absorption Spectroscopy Technique

    PubMed Central

    Karpiuk, Uliana Vladimirovna; Al Azzam, Khaldun Mohammad; Abudayeh, Zead Helmi Mahmoud; Kislichenko, Viktoria; Naddaf, Ahmad; Cholak, Irina; Yemelianova, Oksana

    2016-01-01

    Purpose: To determine the elements in Bryonia alba L. roots, collected from the Crimean Peninsula region in Ukraine. Methods: Dry ashing was used as a flexible method and all elements were determined using atomic absorption spectrometry (AAS) equipped with flame and graphite furnace. Results: The average concentrations of the determined elements, expressed as mg/100 g dry weight of the sample, were as follow: 13.000 for Fe, 78.000 for Si, 88.000 for P, 7.800 for Al, 0.130 for Mn, 105.000 for Mg, 0.030 for Pb, 0.052 for Ni, 0.030 for Mo, 210.000 for Ca, 0.130 for Cu, 5.200 for Zn, 13.000 for Na, 1170.000 for K, 0.780 for Sr, 0.030 for Co, 0.010 for Cd, 0.010 for As, and 0.010 for Hg. Toxic elements such as Cd and Pb were also found but at very low concentration. Among the analyzed elements, K was the most abundant followed by Ca, Mg, P, Si, Fe, Na, and Zn, whereas Hg, As, Cd, Co, Mo, and Pb were found in low concentration. Conclusion: The results suggest that the roots of Bryonia alba L. plant has potential medicinal property through their high element contents present. Moreover, it showed that the AAS method is a simple, fast, and reliable for the determination of elements in plant materials. The obtained results of the current study provide justification for the usage of such fruit in daily diet for nutrition and for medicinal usage in the treatment of various diseases. PMID:27478794

  17. Evaluation of the memory effect on gold-coated silica adsorption tubes used for the analysis of gaseous mercury by cold vapor atomic absorption spectrometry.

    PubMed

    Rahman, Mohammad Mahmudur; Brown, Richard J C; Kim, Ki-Hyun; Yoon, Hye-On; Phan, Nhu-Thuc

    2013-01-01

    In an effort to reduce the experimental bias involved in the analysis of gaseous elemental mercury (Hg(o)), the blank response from gold-coated adsorption tubes has been investigated using cold vapor atomic absorption spectrometry (CVAAS). Our study has been compared with our recent investigation on memory effect in a cold vapour atomic fluorescence spectrometry (CVAFS). The pattern of blank responses was quantified after loading different amounts of mercury and after different time intervals of 1, 14, and 45 days. In case of the one day interval, the result of five to six instant blank heating cycles confirmed successful liberation of mercury following the second and third blank heating cycles. The results of 14 or 45 days generally suggest that liberation of excess mercury is affected by both the initial loading amount and the length of storage time prior to analysis. We have demonstrated a possibly effective way to reduce memory effects. Some similarities of these results with those from CVAFS experiment suggests that the blank response is caused by a combination of mercury absorbed within the bulk gold and micro- and nanoparticles liberated during heating and not from coabsorbing interfering gaseous species.

  18. Evaluation of the Memory Effect on Gold-Coated Silica Adsorption Tubes Used for the Analysis of Gaseous Mercury by Cold Vapor Atomic Absorption Spectrometry

    PubMed Central

    Rahman, Mohammad Mahmudur; Brown, Richard J. C.; Yoon, Hye-On; Phan, Nhu-Thuc

    2013-01-01

    In an effort to reduce the experimental bias involved in the analysis of gaseous elemental mercury (Hgo), the blank response from gold-coated adsorption tubes has been investigated using cold vapor atomic absorption spectrometry (CVAAS). Our study has been compared with our recent investigation on memory effect in a cold vapour atomic fluorescence spectrometry (CVAFS). The pattern of blank responses was quantified after loading different amounts of mercury and after different time intervals of 1, 14, and 45 days. In case of the one day interval, the result of five to six instant blank heating cycles confirmed successful liberation of mercury following the second and third blank heating cycles. The results of 14 or 45 days generally suggest that liberation of excess mercury is affected by both the initial loading amount and the length of storage time prior to analysis. We have demonstrated a possibly effective way to reduce memory effects. Some similarities of these results with those from CVAFS experiment suggests that the blank response is caused by a combination of mercury absorbed within the bulk gold and micro- and nanoparticles liberated during heating and not from coabsorbing interfering gaseous species. PMID:23589708

  19. Use of an online extraction liquid chromatography quadrupole time-of-flight tandem mass spectrometry method for the characterization of polyphenols in Citrus paradisi cv. Changshanhuyu peel.

    PubMed

    Tong, Chaoying; Peng, Mijun; Tong, Runna; Ma, Ruyi; Guo, Keke; Shi, Shuyun

    2018-01-19

    Chemical profiling of natural products by high performance liquid chromatography (HPLC) was critical for understanding of their clinical bioactivities, and sample pretreatment steps have been considered as a bottleneck for analysis. Currently, concerted efforts have been made to develop sample pretreatment methods with high efficiency, low solvent and time consumptions. Here, a simple and efficient online extraction (OLE) strategy coupled with HPLC-diode array detector-quadrupole time-of-flight tandem mass spectrometry (HPLC-DAD-QTOF-MS/MS) was developed for rapid chemical profiling. For OLE strategy, guard column inserted with ground sample (2 mg) instead of sample loop was connected with manual injection valve, in which components were directly extracted and transferred to HPLC-DAD-QTOF-MS/MS system only by mobile phase without any extra time, solvent, instrument and operation. By comparison with offline heat-reflux extraction of Citrus paradisi cv. Changshanhuyu (Changshanhuyu) peel, OLE strategy presented higher extraction efficiency perhaps because of the high pressure and gradient elution mode. A total of twenty-two secondary metabolites were detected according to their retention times, UV spectra, exact mass, and fragmentation ions in MS/MS spectra, and nine of them were discovered in Changshanhuyu peel for the first time to our knowledge. It is concluded that the developed OLE-HPLC-DAD-QTOF-MS/MS system offers new perspectives for rapid chemical profiling of natural products. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION, AND MAINTENANCE OF THE PERKIN-ELMER ZEEMAN/5000 SYSTEM ATOMIC ABSORPTION SPECTROPHOTOMETER (BCO-L-6.0)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5000 atomic absorption spectrophotometer (PE 5000 AA), and the Perkin Elmer 5000 Zeeman graphite furnace atomic absorption spectrophotometer (PE 5000Z GFAA)...

  1. Determination and Uncertainty Analysis of Inorganic Arsenic in Husked Rice by Solid Phase Extraction and Atomic Absorption Spectrometry with Hydride Generation.

    PubMed

    Saxena, Sushil Kumar; Karipalli, Agnes Raju; Krishnan, Anoop A; Rangasamy, Rajesh; Malekadi, Praveen; Singh, Dhirendra P; Vasu, Vimesh; Singh, Vijay K

    2017-05-01

    This study enables the selective determination of inorganic arsenic (iAs) with a low detection limit using an economical instrument [atomic absorption spectrometer with hydride generation (HG)] to meet the regulatory requirements as per European Commission (EC) and Codex guidelines. Dry rice samples (0.5 g) were diluted using 0.1 M HNO3-3% H2O2 and heated in a water bath (90 ± 2°C) for 60 min. Through this process, all the iAs is solubilized and oxidized to arsenate [As(V)]. The centrifuged extract was loaded onto a preconditioned and equilibrated strong anion-exchange SPE column (silica-based Strata SAX 500 mg/6 mL), followed by selective and sequential elution of As(V), enabling the selective quantification of iAs using atomic absorption spectrometry with HG. In-house validation showed a mean recovery of 94% and an LOQ of 0.025 mg/kg. The repeatability (HorRatr) and reproducibility (HorRatR) values were <2, meeting the performance criteria mandated by the EC. The combined standard measurement uncertainty by this method was less than the maximum standard measurement uncertainty; thus, the method can be considered for official control purposes. The method was applied for the determination of iAs in husked rice samples and has potential applications in other food commodities.

  2. Obesity is a significant susceptibility factor for idiopathic AA amyloidosis.

    PubMed

    Blank, Norbert; Hegenbart, Ute; Dietrich, Sascha; Brune, Maik; Beimler, Jörg; Röcken, Christoph; Müller-Tidow, Carsten; Lorenz, Hanns-Martin; Schönland, Stefan O

    2018-03-01

    To investigate obesity as susceptibility factor in patients with idiopathic AA amyloidosis. Clinical, biochemical and genetic data were obtained from 146 patients with AA amyloidosis. Control groups comprised 40 patients with long-standing inflammatory diseases without AA amyloidosis and 56 controls without any inflammatory disease. Patients with AA amyloidosis had either familial Mediterranean fever (FMF) or long-standing rheumatic diseases as underlying inflammatory disease (n = 111, median age 46 years). However, in a significant proportion of patients with AA amyloidosis no primary disease was identified (idiopathic AA; n = 37, median age 60 years). Patients with idiopathic AA amyloidosis were more obese and older than patients with AA amyloidosis secondary to FMF or rheumatic diseases. Serum leptin levels correlated with the body mass index (BMI) in all types of AA amyloidosis. Elevated leptin levels of more than 30 µg/l were detected in 18% of FMF/rheumatic + AA amyloidosis and in 40% of patients with idiopathic AA amyloidosis (p = .018). Finally, the SAA1 polymorphism was confirmed as a susceptibility factor for AA amyloidosis irrespective of the type of the disease. Obesity, age and the SAA1 polymorphism are susceptibility factors for idiopathic AA amyloidosis. Recent advances in treatment of FMF and rheumatic disorders will decrease the incidence of AA amyloidosis due to these diseases. Idiopathic AA, however, might be an emerging problem in the ageing and increasingly obese population.

  3. Differential phenolic production in leaves of Vitis vinifera cv. Alvarinho affected with esca disease.

    PubMed

    Lima, Marta R M; Felgueiras, Mafalda L; Cunha, Ana; Chicau, Gisela; Ferreres, Federico; Dias, Alberto C P

    2017-03-01

    Esca is a destructive disease of complex etiology affecting grapevines worldwide. A major constraint to the study and control of esca is that the disease is not diagnosed until external leaf and/or fruit symptoms are visible; however external symptoms usually appear several years after infection onset. We studied the phenolic content of V. vinifera cv. Alvarinho leaves using high performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS)/LC-MS. Leaves from affected cordons with and without visible symptoms (diseased and apparently healthy leaves, respectively) and leaves from asymptomatic cordons (healthy leaves) were analyzed. Application of principal components analysis (PCA) to HPLC data showed a clear separation between diseased, apparently healthy, and healthy leaves, with the apparently healthy leaves clustered in a medial position. Several compounds were highly correlated with diseased leaves indicating a differential phenolic production due to esca disease in V. vinifera cv. Alvarinho leaves. Total phenolic production was shown to significantly increase in diseased leaves, compared to healthy leaves, with apparently healthy leaves containing a medial amount. Trans-caffeoyltartaric acid, trans-coumaroyl-tartaric acid, quercetin-3-O-glucoside, quercetin-3-O-galactoside, kaempferol-3-glucoside and myricetin were identified among the compounds associated with disease and their content shown to change similarly to total phenolic production. This study shows that it is possible to discriminate between diseased, healthy and apparently healthy leaves by applying PCA to HPLC data. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. AAS Career Services

    NASA Astrophysics Data System (ADS)

    Marvel, Kevin B.

    2012-08-01

    The American Astronomical Society provides substantial programs in the area of Career Services.Motivated by the Society's mission to enhance and share humanity's understanding of the Universe, the AAS provides a central resource for advertising positions, interviewing opportunities at its annual winter meeting and information, workshops and networks to enable astronomers to find employment.The programs of the Society in this area are overseen by an active committee on employment and the AAS Council itself.Additional resources that help characterize the field, its growth and facts about employment such as salaries and type of jobs available are regularly summarized and reported on by the American Institute of Physics.

  5. Lithogeochemistry of mineralized and altered rock samples from the northern Talkeetna Mountains, south-central Alaska

    USGS Publications Warehouse

    Light, Thomas D.; Schmidt, Jeanine M.

    2011-01-01

    Mineralized and altered rock samples collected from the northern Talkeetna Mountains, Alaska, were analyzed by two different inductively coupled plasma atomic-emission spectrometry (ICP-AES) methods for as many as 44 elements; by fire assay and either direct-coupled plasma (DCP) or atomic absorption spectrophotometry (AAS) for gold (Au); by cold vapor atomic absorption (CVAA) for mercury (Hg); and by irradiated neutron activation analysis (INAA) for tungsten (W). The analytical results showed that some samples contain high values of multiple elements and may be potential indicators of hydrothermal mineralization in the area.

  6. Ligandless dispersive liquid--liquid microextraction of iron in biological and foodstuff samples and its determination by Electrothermal atomic absorption spectrometry.

    PubMed

    Madadizadeh, Mohadeseh; Taher, Mohammad Ali; Ashkenani, Hamid

    2013-01-01

    A new, simple, and efficient method comprising ligandless dispersive liquid-liquid microextraction combined with electrothermal atomic absorption spectrometry is reported for the preconcentration and determination of ultratrace amounts of Fe(III). Carbon tetrachloride and acetone were used as the extraction and disperser solvents, respectively. Some effective parameters of the microextraction such as choice of extraction and disperser solvents, their volume, extraction time and temperature, salt and surfactant effect, and pH were optimized. Under the optimum conditions, the calibration curve was linear in the range of 0.02 to 0.46 microg/L of Fe(III), with LOD and LOQ of 5.2 and 17.4 ng/L, respectively. The RSD for seven replicated determinations of Fe(IIl) ion at 0.1 microg/L concentration level was 5.2%. Operational simplicity, rapidity, low cost, good repeatability, and low consumption of extraction solvent are the main advantages of the proposed method. The method was successfully applied to the determination of iron in biological, food, and certified reference samples.

  7. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of whole-water recoverable arsenic, boron, and vanadium using inductively coupled plasma-mass spectrometry

    USGS Publications Warehouse

    Garbarino, John R.

    2000-01-01

    Analysis of in-bottle digestate by using the inductively coupled plasma?mass spectrometric (ICP?MS) method has been expanded to include arsenic, boron, and vanadium. Whole-water samples are digested by using either the hydrochloric acid in-bottle digestion procedure or the nitric acid in-bottle digestion procedure. When the hydrochloric acid in-bottle digestion procedure is used, chloride must be removed from the digestate by subboiling evaporation before arsenic and vanadium can be accurately determined. Method detection limits for these elements are now 10 to 100 times lower than U.S. Geological Survey (USGS) methods using hydride generation? atomic absorption spectrophotometry (HG? AAS) and inductively coupled plasma? atomic emission spectrometry (ICP?AES), thus providing lower variability at ambient concentrations. The bias and variability of the methods were determined by using results from spike recoveries, standard reference materials, and validation samples. Spike recoveries in reagent-water, surface-water, ground-water, and whole-water recoverable matrices averaged 90 percent for seven replicates; spike recoveries were biased from 25 to 35 percent low for the ground-water matrix because of the abnormally high iron concentration. Results for reference material were within one standard deviation of the most probable value. There was no significant difference between the results from ICP?MS and HG?AAS or ICP?AES methods for the natural whole-water samples that were analyzed.

  8. EARTH, MOON, SUN, AND CV ACCRETION DISKS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Montgomery, M. M.

    2009-11-01

    Net tidal torque by the secondary on a misaligned accretion disk, like the net tidal torque by the Moon and the Sun on the equatorial bulge of the spinning and tilted Earth, is suggested by others to be a source to retrograde precession in non-magnetic, accreting cataclysmic variable (CV) dwarf novae (DN) systems that show negative superhumps in their light curves. We investigate this idea in this work. We generate a generic theoretical expression for retrograde precession in spinning disks that are misaligned with the orbital plane. Our generic theoretical expression matches that which describes the retrograde precession of Earths'more » equinoxes. By making appropriate assumptions, we reduce our generic theoretical expression to those generated by others, or to those used by others, to describe retrograde precession in protostellar, protoplanetary, X-ray binary, non-magnetic CV DN, quasar, and black hole systems. We find that spinning, tilted CV DN systems cannot be described by a precessing ring or by a precessing rigid disk. We find that differential rotation and effects on the disk by the accretion stream must be addressed. Our analysis indicates that the best description of a retrogradely precessing spinning, tilted, CV DN accretion disk is a differentially rotating, tilted disk with an attached rotating, tilted ring located near the innermost disk annuli. In agreement with the observations and numerical simulations by others, we find that our numerically simulated CV DN accretion disks retrogradely precess as a unit. Our final, reduced expression for retrograde precession agrees well with our numerical simulation results and with selective observational systems that seem to have main-sequence secondaries. Our results suggest that a major source to retrograde precession is tidal torques like that by the Moon and the Sun on the Earth. In addition, these tidal torques should be common to a variety of systems where one member is spinning and tilted, regardless

  9. Method development for the control determination of mercury in seafood by solid-sampling thermal decomposition amalgamation atomic absorption spectrometry (TDA AAS).

    PubMed

    Torres, D P; Martins-Teixeira, M B; Silva, E F; Queiroz, H M

    2012-01-01

    A very simple and rapid method for the determination of total mercury in fish samples using the Direct Mercury Analyser DMA-80 was developed. In this system, a previously weighted portion of fresh fish is combusted and the released mercury is selectively trapped in a gold amalgamator. Upon heating, mercury is desorbed from the amalgamator, an atomic absorption measurement is performed and the mercury concentration is calculated. Some experimental parameters have been studied and optimised. In this study the sample mass was about 100.0 mg. The relative standard deviation was lower than 8.0% for all measurements of solid samples. Two calibration curves against aqueous standard solutions were prepared through the low linear range from 2.5 to 20.0 ng of Hg, and the high linear range from 25.0 to 200.0 ng of Hg, for which a correlation coefficient better than 0.997 was achieved, as well as a normal distribution of the residuals. Mercury reference solutions were prepared in 5.0% v/v nitric acid medium. Lyophilised fish tissues were also analysed; however, the additional procedure had no advantage over the direct analysis of the fresh fish, and additionally increased the total analytical process time. A fish tissue reference material, IAEA-407, was analysed and the mercury concentration was in agreement with the certified value, according to the t-test at a 95% confidence level. The limit of quantification (LOQ), based on a mercury-free sample, was 3.0 µg kg(-1). This LOQ is in accordance with performance criteria required by the Commission Regulation No. 333/2007. Simplicity and high efficiency, without the need for any sample preparation procedure, are some of the qualities of the proposed method.

  10. Limited geographic distribution of the novel cyclovirus CyCV-VN.

    PubMed

    Le, Van Tan; de Jong, Menno D; Nguyen, Van Kinh; Nguyen, Vu Trung; Taylor, Walter; Wertheim, Heiman F L; van der Ende, Arie; van der Hoek, Lia; Canuti, Marta; Crusat, Martin; Sona, Soeng; Nguyen, Hanh Uyen; Giri, Abhishek; Nguyen, Thi Thuy Chinh Bkrong; Ho, Dang Trung Nghia; Farrar, Jeremy; Bryant, Juliet E; Tran, Tinh Hien; Nguyen, Van Vinh Chau; van Doorn, H Rogier

    2014-02-05

    A novel cyclovirus, CyCV-VN, was recently identified in cerebrospinal fluid (CSF) from patients with central nervous system (CNS) infections in central and southern Vietnam. To explore the geographic distribution of this novel virus, more than 600 CSF specimens from patients with suspected CNS infections in northern Vietnam, Cambodia, Nepal and The Netherlands were screened for the presence of CyCV-VN but all were negative. Sequence comparison and phylogenetic analysis between CyCV-VN and another novel cyclovirus recently identified in CSF from Malawian patients indicated that these represent distinct cycloviral species, albeit phylogenetically closely related. The data suggest that CyCV-VN has a limited geographic distribution within southern and central Vietnam. Further research is needed to determine the global distribution and diversity of cycloviruses and importantly their possible association with human disease.

  11. High-protein distillers dried grains with solubles produced using a novel front-end-back-end fractionation technology has greater nutritional value than conventional distillers dried grains with solubles when fed to growing pigs.

    PubMed

    Espinosa, C D; Stein, H H

    2018-05-04

    Two experiments were conducted to determine the standardized ileal digestibility (SID) of CP and AA, apparent total tract digestibility (ATTD) of GE, and DE and ME in conventional distillers dried grains with solubles (DDGS-CV) and in a novel source of high-protein distillers dried grains with solubles (DDGS-HP) produced by Lincolnway Energy (Nevada, IA). In Exp. 1, 18 barrows (initial BW: 72.47 ± 9.16 kg) that had a T-cannula installed in the distal ileum were allotted to a completely randomized design with 3 diets and 6 replicate pigs per diet. A nitrogen-free diet and 2 diets that contained cornstarch and DDGS-CV or DDGS-HPLincolnway as the sole source of CP and AA were formulated. Diets were fed to pigs for 7 d, and ileal digesta were collected on days 6 and 7 of each period. The SID for Leu, Lys, Met, Phe, and Glu was greater (P < 0.05) in DDGS-HPLincolnway than in DDGS-CV, and the SID of Ile, Val, and total indispensable AA, as well as the SID of Tyr, tended to be greater (P < 0.10) in DDGS-HPLincolnway than in DDGS-CV. No difference between DDGS-CV and DDGS-HPLincolnway was observed for the SID of CP and all other AA. In Exp. 2, 24 barrows (initial BW: 52.80 ± 2.55 kg) were housed individually in metabolism crates and randomly allotted to 1 of 3 diets. A corn-based basal diet (97.25% corn) and 2 diets that contained corn and DDGS-CV or corn and DDGS-HPLincolnway were formulated. Each diet was fed to 8 pigs. Feces and urine were collected using the marker to marker approach with 7-d adaptation and 5-d collection periods. The DE and ME in DDGS-CV and DDGS-HPLincolnway were calculated using the difference procedure. The DE and ME in DDGS-HPLincolnway on an as-fed basis were greater (P < 0.05) than in corn and DDGS-CV, but the ATTD of GE in DDGS-HPLincolnway and DDGS-CV was less (P < 0.01) than in corn. In conclusion, the SID of some AA and the DE and ME in DDGS-HPLincolnway were greater than in DDGS-CV.

  12. Determination of lead in flour samples directly by solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Tinas, Hande; Ozbek, Nil; Akman, Suleyman

    2018-02-01

    In this study, lead concentrations in various flour samples were determined by high-resolution continuum source graphite furnace atomic absorption spectrometry with solid sampling. Since samples were analyzed directly, the risks and disadvantages of sample digestion were eliminated. Solid flour samples were dried, weighed on the platforms, Pd was added as a modifier and introduced directly into a graphite tube using a manual solid sampler. Platforms and tubes were coated with Zr. The optimized pyrolysis and atomization temperatures were 800 °C and 2200 °C, respectively. The sensitivities of lead in various flour certified reference materials (CRMs) and aqueous standards were not significantly different. Therefore, aqueous standards were safely used for calibration. The absolute limit of detection and characteristic mass were 7.2 pg and 9.0 pg of lead, respectively. The lead concentrations in different types of flour samples were found in the range of 25-52 μg kg- 1. Finally, homogeneity factors representing the heterogeneity of analyte distribution for lead in flour samples were determined.

  13. Atmospheric heavy metal deposition in Northern Vietnam: Hanoi and Thainguyen case study using the moss biomonitoring technique, INAA and AAS.

    PubMed

    Viet, Hung Nguyen; Frontasyeva, Marina Vladimirovna; Thi, Thu My Trinh; Gilbert, Daniel; Bernard, Nadine

    2010-06-01

    The moss technique is widely used to monitor atmospheric deposition of heavy metals in many countries in Europe, whereas this technique is scarcely used in Asia. To implement this international reliable and cheap methodology in the Asian countries, it is necessary to find proper moss types typical for the Asian environment and suitable for the biomonitoring purposes. Such a case study was undertaken in Vietnam for assessing the environmental situation in strongly contaminated areas using local species of moss Barbula indica. The study is focused on two areas characterized by different pollution sources: the Hanoi urban area and the Thainguyen metallurgical zone. Fifty-four moss samples were collected there according to standard sampling procedure adopted in Europe. Two complementary analytical techniques, atomic absorption spectrometry (AAS) and instrumental neutron activation analysis (INAA), were used for determination of elemental concentrations in moss samples. To characterize the pollution sources, multivariate statistical analysis was applied. A total of 38 metal elements were determined in the moss by the two analytical techniques. The results of descriptive statistics of metal concentration in moss from the city center and periphery of Hanoi determined by AAS are presented. The similar results for moss from Thainguyen province determined by INAA and AAS are given also. A comparison of mean elemental concentrations in moss of this work with those in different environmental conditions of other authors provides reasonable information on heavy metal atmospheric deposition levels. Factor loadings and factor scores were used to identify and apportion contamination sources at the sampling sites. The values of percentage of total of factors show two highly different types of pollution in the two examined areas-the Hanoi pollution composition with high portion of urban-traffic activity and soil dust (62%), and the one of Thainguyen with factors related to industrial

  14. AAS Oral History Project

    NASA Astrophysics Data System (ADS)

    Buxner, Sanlyn; Holbrook, Jarita; AAS Oral History Team

    2016-06-01

    Now in its fourth year, the AAS Oral History Project has interviewed over 80 astronomers from all over the world. Led by the AAS Historical Astronomy Division (HAD) and partially funded by the American Institute of Physics Niels Bohr Library and ongoing support from the AAS, volunteers have collected oral histories from astronomers at professional meetings starting in 2015, including AAS, DPS, and the IAU general assembly. Each interview lasts one and a half to two hours and focuses on interviewees’ personal and professional lives. Questions include those about one’s family, childhood, strong influences on one’s scientific career, career path, successes and challenges, perspectives on how astronomy is changing as a field, and advice to the next generation. Each interview is audio recorded and transcribed, the content of which is checked with each interviewee. Once complete, interview transcripts are posted online as part of a larger oral history library at https://www.aip.org/history-programs/niels-bohr-library/oral-histories. Future analysis will reveal a rich story of astronomers and will help the community address issues of diversity, controversies, and the changing landscape of science. We are still recruiting individuals to be interviewed from all stages of career from undergraduate students to retired and emeritus astronomers. Contact Jarita Holbrook to schedule an interview or to find out more information about the project (astroholbrook@gmail.com). Also, contact Jarita Holbrook if you would like to become an interviewer for the project.

  15. Two new advanced forms of spectrometry for space and commercial applications

    NASA Technical Reports Server (NTRS)

    Schlager, Kenneth J.

    1991-01-01

    Reagentless ultraviolet absorption spectrometry (UVAS) and Liquid Atomic Emission Spectrometry (LAES) represent new forms of spectrometry with extensive potential in both space and commercial applications. Originally developed under KSC sponsorship for monitoring nutrient solutions for the Controlled Ecological Life Support System (CELSS), both UVAS and LAES have extensive analytical capabilities for both organic and inorganic chemical compounds. Both forms of instrumentation involve the use of remote fiber optic probes and real-time measurements for on-line process monitoring. Commercial applications exist primarily in environmental analysis and for process control in the chemical, pulp and paper, food processing, metal plating, and water/wastewater treatment industries.

  16. Sequential injection ionic liquid dispersive liquid-liquid microextraction for thallium preconcentration and determination with flame atomic absorption spectrometry.

    PubMed

    Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

    2012-08-01

    A novel, automatic on-line sequential injection dispersive liquid-liquid microextraction (SI-DLLME) method, based on 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF(6)]) ionic liquid as an extractant solvent was developed and demonstrated for trace thallium determination by flame atomic absorption spectrometry. The ionic liquid was on-line fully dispersed into the aqueous solution in a continuous flow format while the TlBr(4)(-) complex was easily migrated into the fine droplets of the extractant due to the huge contact area of them with the aqueous phase. Furthermore, the extractant was simply retained onto the surface of polyurethane foam packed into a microcolumn. No specific conditions like low temperature are required for extractant isolation. All analytical parameters of the proposed method were investigated and optimized. For 15 mL of sample solution, an enhancement factor of 290, a detection limit of 0.86 μg L(-1) and a precision (RSD) of 2.7% at 20.0 μg L(-1) Tl(I) concentration level, was obtained. The developed method was evaluated by analyzing certified reference materials while good recoveries from environmental and biological samples proved that present method was competitive in practical applications.

  17. Determination of ultra-trace aluminum in human albumin by cloud point extraction and graphite furnace atomic absorption spectrometry.

    PubMed

    Sun, Mei; Wu, Qianghua

    2010-04-15

    A cloud point extraction (CPE) method for the preconcentration of ultra-trace aluminum in human albumin prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. The CPE method was based on the complex of Al(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 34.8 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of Al(III) was 0.06 ng mL(-1). The relative standard deviation (n=7) of sample was 3.6%, values of recovery of aluminum were changed from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination of ultra-trace aluminum in human albumin. 2009 Elsevier B.V. All rights reserved.

  18. In-situ suspended aggregate microextraction of gold nanoparticles from water samples and determination by electrothermal atomic absorption spectrometry.

    PubMed

    Choleva, Tatiana G; Kappi, Foteini A; Tsogas, George Z; Vlessidis, Athanasios G; Giokas, Dimosthenis L

    2016-05-01

    This work describes a new method for the extraction and determination of gold nanoparticles in environmental samples by means of in-situ suspended aggregate microextraction and electrothermal atomic absorption spectrometry. The method relies on the in-situ formation of a supramolecular aggregate phase through ion-association between a cationic surfactant and a benzene sulfonic acid derivative. Gold nanoparticles are physically entrapped into the aggregate phase which is separated from the bulk aqueous solution by vacuum filtration on the surface of a cellulose filter in the form of a thin film. The film is removed from the filter surface and is dissociated into an acidified methanolic solution which is used for analysis. Under the optimized experimental conditions, gold nanoparticles can be efficiently extracted from water samples with recovery rates between 81.0-93.3%, precision 5.4-12.0% and detection limits as low as 75femtomolL(-1) using only 20mL of sample volume. The satisfactory analytical features of the method along with the simplicity indicate the efficiency of this new approach to adequately collect and extract gold nanoparticle species from water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Anonymous voting for multi-dimensional CV quantum system

    NASA Astrophysics Data System (ADS)

    Rong-Hua, Shi; Yi, Xiao; Jin-Jing, Shi; Ying, Guo; Moon-Ho, Lee

    2016-06-01

    We investigate the design of anonymous voting protocols, CV-based binary-valued ballot and CV-based multi-valued ballot with continuous variables (CV) in a multi-dimensional quantum cryptosystem to ensure the security of voting procedure and data privacy. The quantum entangled states are employed in the continuous variable quantum system to carry the voting information and assist information transmission, which takes the advantage of the GHZ-like states in terms of improving the utilization of quantum states by decreasing the number of required quantum states. It provides a potential approach to achieve the efficient quantum anonymous voting with high transmission security, especially in large-scale votes. Project supported by the National Natural Science Foundation of China (Grant Nos. 61272495, 61379153, and 61401519), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130162110012), and the MEST-NRF of Korea (Grant No. 2012-002521).

  20. Rating AAs.

    ERIC Educational Resources Information Center

    Carter, Susan J.

    2001-01-01

    Why alternative investments? In a word: performance. Many higher education endowment and foundation managers are making increasing commitments to alternative investments, or AAs, in order to obtain higher returns and broader diversification for their investment portfolios than public securities instruments can usually provide. Learn how to handle…

  1. Determination of trace nickel in hydrogenated cottonseed oil by electrothermal atomic absorption spectrometry after microwave-assisted digestion.

    PubMed

    Zhang, Gai

    2012-01-01

    Microwave digestion of hydrogenated cottonseed oil prior to trace nickel determination by electrothermal atomic absorption spectrometry (ETAAS) is proposed here for the first time. Currently, the methods outlined in U.S. Pharmacopeia 28 (USP28) or British Pharmacopeia (BP2003) are recommended as the official methods for analyzing nickel in hydrogenated cottonseed oil. With these methods the samples may be pre-treated by a silica or a platinum crucible. However, the samples were easily tarnished during sample pretreatment when using a silica crucible. In contrast, when using a platinum crucible, hydrogenated cottonseed oil acting as a reducing material may react with the platinum and destroy the crucible. The proposed microwave-assisted digestion avoided tarnishing of sample in the process of sample pretreatment and also reduced the cycle of analysis. The programs of microwave digestion and the parameters of ETAAS were optimized. The accuracy of the proposed method was investigated by analyzing real samples. The results were compared with the ones by pressurized-PTFE-bomb acid digestion and ones obtained by the U.S. Pharmacopeia 28 (USP28) method. The new method involves a relatively rapid matrix destruction technique compared with other present methods for the quantification of metals in oil. © 2011 Institute of Food Technologists®

  2. Functionalized-graphene modified graphite electrode for the selective determination of dopamine in presence of uric acid and ascorbic acid.

    PubMed

    Mallesha, Malledevaru; Manjunatha, Revanasiddappa; Nethravathi, C; Suresh, Gurukar Shivappa; Rajamathi, Michael; Melo, Jose Savio; Venkatesha, Thimmappa Venkatarangaiah

    2011-06-01

    Graphene is chemically synthesized by solvothermal reduction of colloidal dispersions of graphite oxide. Graphite electrode is modified with functionalized-graphene for electrochemical applications. Electrochemical characterization of functionalized-graphene modified graphite electrode (FGGE) is carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The behavior of FGGE towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) has been investigated by CV, differential pulse voltammetry (DPV) and chronoamperommetry (CA). The FGGE showed excellent catalytic activity towards electrochemical oxidation of AA, DA and UA compared to that of the bare graphite electrode. The electrochemical oxidation signals of AA, DA and UA are well separated into three distinct peaks with peak potential separation of 193mv, 172mv and 264mV between AA-DA, DA-UA and AA-UA respectively in CV studies and the corresponding peak potential separations in DPV mode are 204mv, 141mv and 345mv. The FGGE is successfully used for the simultaneous detection of AA, DA and UA in their ternary mixture and DA in serum and pharmaceutical samples. The excellent electrocatalytic behavior of FGGE may lead to new applications in electrochemical analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. A new concept of efficient therapeutic drug monitoring using the high-resolution continuum source absorption spectrometry and the surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Xing, Yanlong; Fuss, Harald; Lademann, Jürgen; Huang, Mao Dong; Becker-Ross, Helmut; Florek, Stefan; Patzelt, Alexa; Meinke, Martina C.; Jung, Sora; Esser, Norbert

    2018-04-01

    In this study, a new therapeutic drug monitoring approach has been tested based on the combination of CaF molecular absorption using high-resolution continuum source absorption spectrometry (HR-CSAS) and surface enhanced Raman spectroscopy (SERS). HR-CSAS with mini graphite tube was successfully tested for clinical therapeutic drug monitoring of the fluorine-containing drug capecitabine in sweat samples of cancer patients: It showed advantageous features of high selectivity (no interference from Cl), high sensitivity (characteristic mass of 0.1 ng at CaF 583.069 nm), low sample consumption (down to 30 nL) and fast measurement (no sample pretreatment and less than 1 min of responding time) in tracing the fluorine signal out of capecitabine. However, this technique has the disadvantage of the total loss of the drug's structure information after burning the sample at very high temperature. Therefore, a new concept of combining HR-CSAS with a non-destructive spectroscopic method (SERS) was proposed for the sensitive sensing and specific identification of capecitabine. We tested and succeed in obtaining the molecular characteristics of the metabolite of capecitabine (named 5-fluorouracil) by the non-destructive SERS technique. With the results shown in this work, it is demonstrated that the combined spectroscopic technique of HR-CSAS and SERS will be very useful in efficient therapeutic drug monitoring in the future.

  4. Human Vitamin B12 Absorption and Metabolism are Measured by Accelerator Mass Spectrometry Using Specifically Labeled 14C-Cobalamin

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carkeet, C; Dueker, S R; Lango, J

    2006-01-26

    There is need for an improved test of human ability to assimilate dietary vitamin B{sub 12}. Assaying and understanding absorption and uptake of B{sub 12} is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of {sup 14}C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 ({sup 14}C) in microliter volumes of biological samples, with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B{sub 12} in the range of normal dietary intake.more » The B{sub 12} used was quantitatively labeled with {sup 14}C at one particular atom of the DMB moiety by exploiting idiosyncrasies of Salmonellametabolism. In order to grow aerobically on ethanolamine, S. entericamust be provided with either pre-formed B{sub 12} or two of its precursors: cobinamide and dimethylbenzimidazole (DMB). When provided with {sup 14}C-DMB specifically labeled in the C2 position, cells produced {sup 14}C-B{sub 12} of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 mg, 2.2 KBq/59 nCi) of purified {sup 14}C-B{sub 12} was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B{sub 12} assimilation.« less

  5. Radial measurements of IMF-sensitive absorption features in two massive ETGs

    NASA Astrophysics Data System (ADS)

    Vaughan, Sam P.; Davies, Roger L.; Zieleniewski, Simon; Houghton, Ryan C. W.

    2018-03-01

    We make radial measurements of stellar initial mass function (IMF) sensitive absorption features in the two massive early-type galaxies NGC 1277 and IC 843. Using the Oxford Short Wavelength Integral Field specTrogaph (SWIFT), we obtain resolved measurements of the Na I 0.82 and FeH 0.99 indices, amongst others, finding both galaxies show strong gradients in Na I absorption combined with flat FeH profiles at ˜0.4 Å. We find these measurements may be explained by radial gradients in the IMF, appropriate abundance gradients in [Na/Fe] and [Fe/H], or a combination of the two, and our data are unable to break this degeneracy. We also use full spectral fitting to infer global properties from an integrated spectrum of each object, deriving a unimodal IMF slope consistent with Salpeter in IC 843 (x = 2.27 ± 0.17) but steeper than Salpeter in NGC 1277 (x = 2.69 ± 0.11), despite their similar FeH equivalent widths. Independently, we fit the strength of the FeH feature and compare to the E-MILES and CvD12 stellar population libraries, finding agreement between the models. The IMF values derived in this way are in close agreement with those from spectral fitting in NGC 1277 (x_{CvD}=2.59^{+0.25}_{-0.48}, x_{E-MILES}=2.77± 0.31), but are less consistent in IC 843, with the IMF derived from FeH alone leading to steeper slopes than when fitting the full spectrum (x_{CvD}=2.57^{+0.30}_{-0.41}, x_{E-MILES}=2.72± 0.25). This work highlights the importance of a large wavelength coverage for breaking the degeneracy between abundance and IMF variations, and may bring into doubt the use of the Wing-Ford band as an IMF index if used without other spectral information.

  6. The application of Westcott Formalism k0 NAA method to estimate short and medium lived elements in some Ghanaian herbal medicines complemented by AAS

    NASA Astrophysics Data System (ADS)

    Ayivor, J. E.; Okine, L. K. N.; Dampare, S. B.; Nyarko, B. J. B.; Debrah, S. K.

    2012-04-01

    The epithermal neutron shape factor, α of the inner and outer irradiation sites of the Ghana Research Reactor-1 (GHARR-1) was determined obtaining results of 0.105 for the inner (Channel 1) Irradiation site and 0.020 for the outer (channel 6) irradiation site. The neutron temperatures for the inner and outer irradiation sites were 27 °C and 20 °C, respectively. The α values used in Westcott Formalism k0 INAA was applied to determine multi elements in 13 Ghanaian herbal medicines used by the Centre for Scientific Research into Plant Medicine (CSRPM) for the management of various diseases complemented by Atomic Absorption Spectrometry. They are namely Mist. Antiaris, Mist. Enterica, Mist. Morazia, Mist. Nibima, Mist. Modium, Mist. Ninger, Mist Sodenia, Mist. Tonica, Chardicca Powder, Fefe Powder, Olax Powder, Sirrapac powder and Lippia Tea. Concentrations of Al, As, Br, K, Cl, Cu, Mg, Mn, Na and V were determined by short and medium irradiations at a thermal neutron flux of 5×1011 ncm-2 s-1. Fe, Cr, Pb, Co, Ni, Sn, Ca, Ba, Li and Sb were determined using Atomic Absorption Spectrometry (AAS). Ba, Cu, Li and V were present at trace levels whereas Al, Cl, Na, Ca were present at major levels. K, Br, Mg, Mn, Co, Ni, Fe and Sb were also present at minor levels. Arsenic was not detected in all samples. Standard Reference material, IAEA-V-10 Hay Powder was simultaneously analysed with samples. The precision and accuracy of the method using real samples and standard reference materials were evaluated and within ±10% of the reported value. Multivariate analytical techniques, such as cluster analysis (Q-mode and R-mode CA) and principal component analysis (PCA)/factor analysis (FA), have been applied to evaluate the chemical variations in the herbal medicine dataset. All the 13 samples may be grouped into 2 statistically significant clusters (liquid based and powdered herbal medicines), reflecting the different chemical compositions. R-mode CA and PCA suggest common

  7. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks...

  8. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks...

  9. Development of a Postcolumn Infused-Internal Standard Liquid Chromatography Mass Spectrometry Method for Quantitative Metabolomics Studies.

    PubMed

    Liao, Hsiao-Wei; Chen, Guan-Yuan; Wu, Ming-Shiang; Liao, Wei-Chih; Lin, Ching-Hung; Kuo, Ching-Hua

    2017-02-03

    Quantitative metabolomics has become much more important in clinical research in recent years. Individual differences in matrix effects (MEs) and the injection order effect are two major factors that reduce the quantification accuracy in liquid chromatography-electrospray ionization-mass spectrometry-based (LC-ESI-MS) metabolomics studies. This study proposed a postcolumn infused-internal standard (PCI-IS) combined with a matrix normalization factor (MNF) strategy to improve the analytical accuracy of quantitative metabolomics. The PCI-IS combined with the MNF method was applied for a targeted metabolomics study of amino acids (AAs). D8-Phenylalanine was used as the PCI-IS, and it was postcolumn-infused into the ESI interface for calibration purposes. The MNF was used to bridge the AA response in a standard solution with the plasma samples. The MEs caused signal changes that were corrected by dividing the AA signal intensities by the PCI-IS intensities after adjustment with the MNF. After the method validation, we evaluated the method applicability for breast cancer research using 100 plasma samples. The quantification results revealed that the 11 tested AAs exhibit an accuracy between 88.2 and 110.7%. The principal component analysis score plot revealed that the injection order effect can be successfully removed, and most of the within-group variation of the tested AAs decreased after the PCI-IS correction. Finally, targeted metabolomics studies on the AAs showed that tryptophan was expressed more in malignant patients than in the benign group. We anticipate that a similar approach can be applied to other endogenous metabolites to facilitate quantitative metabolomics studies.

  10. Assembly of the Lactuca sativa, L. cv. Tizian draft genome sequence reveals differences within major resistance complex 1 as compared to the cv. Salinas reference genome.

    PubMed

    Verwaaijen, Bart; Wibberg, Daniel; Nelkner, Johanna; Gordin, Miriam; Rupp, Oliver; Winkler, Anika; Bremges, Andreas; Blom, Jochen; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2018-02-10

    Lettuce (Lactuca sativa, L.) is an important annual plant of the family Asteraceae (Compositae). The commercial lettuce cultivar Tizian has been used in various scientific studies investigating the interaction of the plant with phytopathogens or biological control agents. Here, we present the de novo draft genome sequencing and gene prediction for this specific cultivar derived from transcriptome sequence data. The assembled scaffolds amount to a size of 2.22 Gb. Based on RNAseq data, 31,112 transcript isoforms were identified. Functional predictions for these transcripts were determined within the GenDBE annotation platform. Comparison with the cv. Salinas reference genome revealed a high degree of sequence similarity on genome and transcriptome levels, with an average amino acid identity of 99%. Furthermore, it was observed that two large regions are either missing or are highly divergent within the cv. Tizian genome compared to cv. Salinas. One of these regions covers the major resistance complex 1 region of cv. Salinas. The cv. Tizian draft genome sequence provides a valuable resource for future functional and transcriptome analyses focused on this lettuce cultivar. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture..., CERTIFICATION, AND STANDARDS) United States Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are well...

  12. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture..., CERTIFICATION, AND STANDARDS) United States Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are well...

  13. Phytosterol glycosides reduce cholesterol absorption in humans

    PubMed Central

    Lin, Xiaobo; Ma, Lina; Racette, Susan B.; Anderson Spearie, Catherine L.; Ostlund, Richard E.

    2009-01-01

    Dietary phytosterols inhibit intestinal cholesterol absorption and regulate whole body cholesterol excretion and balance. However, they are biochemically heterogeneous and a portion is glycosylated in some foods with unknown effects on biological activity. We tested the hypothesis that phytosterol glycosides reduce cholesterol absorption in humans. Phytosterol glycosides were extracted and purified from soy lecithin in a novel two-step process. Cholesterol absorption was measured in a series of three single-meal tests given at intervals of 2 wk to each of 11 healthy subjects. In a randomized crossover design, participants received ∼300 mg of added phytosterols in the form of phytosterol glycosides or phytosterol esters, or placebo in a test breakfast also containing 30 mg cholesterol-d7. Cholesterol absorption was estimated by mass spectrometry of plasma cholesterol-d7 enrichment 4–5 days after each test. Compared with the placebo test, phytosterol glycosides reduced cholesterol absorption by 37.6 ± 4.8% (P < 0.0001) and phytosterol esters 30.6 ± 3.9% (P = 0.0001). These results suggest that natural phytosterol glycosides purified from lecithin are bioactive in humans and should be included in methods of phytosterol analysis and tables of food phytosterol content. PMID:19246636

  14. High precision Al-Mg systematics of forsterite-bearing Type B CAIs from CV3 chondrites

    NASA Astrophysics Data System (ADS)

    MacPherson, G. J.; Bullock, E. S.; Tenner, T. J.; Nakashima, D.; Kita, N. T.; Ivanova, M. A.; Krot, A. N.; Petaev, M. I.; Jacobsen, S. B.

    2017-03-01

    In order to further elucidate possible temporal relationships between different varieties of calcium-, aluminum-rich inclusions (CAIs), we measured the aluminum-magnesium isotopic systematics of seven examples of the rare type known as forsterite-bearing Type B (FoB) inclusions from four different CV3 carbonaceous chondrites: Allende, Efremovka, NWA 3118, and Vigarano. The primary phases (forsterite, Al-Ti-rich diopside, spinel, melilite, and anorthite) in each inclusion were analyzed in situ using high-precision secondary ion mass-spectrometry (SIMS). In all cases, minerals with low Al/Mg ratios (all except anorthite) yield well-defined internal Al-Mg isochrons, with a range of initial 26Al/27Al ratios [(26Al/27Al)0] ranging from (5.30 ± 0.22) × 10-5 down to (4.17 ± 0.43) × 10-5. Anorthite in all cases is significantly disturbed relative to the isochrons defined by the other phases in the same CAIs, and in several cases contains no resolved excesses of radiogenic 26Mg (δ26Mg∗) even at 27Al/24Mg ratios greater than 1000. The fact that some FoBs preserve (26Al/27Al)0 of ∼5.2 × 10-5, close to the canonical value of (5.23 ± 0.13) × 10-5 inferred from bulk magnesium-isotope measurements of CV CAIs (B. Jacobsen et al., 2008), demonstrates that FoBs began forming very early, contemporaneous with other more-refractory CAIs. The range of (26Al/27Al)0 values further shows that FoBs continued to be reprocessed over ∼200,000 years of nebular history, consistent with results obtained for other types of igneous CAIs in CV chondrites. The absence of any correlation between of CAI + FoB formation or reprocessing times with bulk composition or CAI type means that there is no temporal evolutionary sequence between the diverse CAI types. The initial δ26Mg∗ value in the most primitive FoB (SJ101) is significantly lower than the canonical solar system value of -0.040 ± 0.029‰.

  15. Flow injection/atomic absorption spectrometric determination of zineb in commercial formulations of pesticide based on slurry sampling.

    PubMed

    Cassella, Ricardo J; Salim, Verĵnica A; Garrigues, Salvador; Santelli, Ricardo E; de la Guardia, Miguel

    2002-11-01

    This paper reports on a new strategy for the slurry sampling determination of dithiocarbamate pesticide zineb [[ethylenebis(dithiocarbamato)]zinc] employing a FIA system with a flame atomic absorption spectrometry detector. In the flow system, an on-line alkaline hydrolysis of the pesticide is performed, allowing the release of Zn(II) ions to the solution, which are easily detected by a flame AAS technique. Several parameters that could affect the performance of the analytical methodology were studied, such as the concentration of NH3(aq) used in the hydrolysis step, the effect of the presence of Triton X-100 on the sensitivity and precision, and the FIA parameters (carrier flow rate and mixing coil volume). Under optimized conditions, aqueous slurries containing 2.5 to 25 microg ml(-1) zineb provided good linear calibration fits. From the obtained data, a detection limit (3sigma) of 1.0 microg ml(-1) zineb was found and a repeatability of 2.7% was obtained from 12 measurements of a slurry containing 2.5 microg m(-1) zineb. On the other hand, a precision (reproducibility) of 7.8% was achieved from three determinations of a sample containing 128 mg g(-1) of the pesticide. Also, the developed system provides a sampling frequency of 72 h(-1).

  16. Bicarbonate absorption stimulates active calcium absorption in the rat proximal tubule.

    PubMed Central

    Bomsztyk, K; Calalb, M B

    1988-01-01

    To evaluate the effect of luminal bicarbonate on calcium reabsorption, rat proximal tubules were perfused in vivo. Perfusion solution contained mannitol to reduce water flux to zero. Total Ca concentration was measured by atomic absorption spectrometry, Ca ion concentration in the tubule lumen (CaL2+) and the peritubular capillary (CaP2+), and luminal pH (pHL) with ion-selective microelectrodes and transepithelial voltage (VTE) with conventional microelectrodes. When tubules were perfused with buffer-free Cl-containing solution, net Ca absorption (JCa) averaged 3.33 pmol/min. Even though VTE was 1.64 mV lumen-positive, CaL2+, 1.05 mM, did not fall below the concentration in the capillary blood, 1.07 mM. When 27 mM of Cl was replaced with HCO3, there was luminal fluid acidification. Despite a decrease in VTE and CaL2+, JCa increased to 7.13 pmol/min, indicating that the enhanced JCa could not be accounted for by the reduced electrochemical gradient, delta CCa. When acetazolamide or an analogue of amiloride was added to the HCO3 solution, JCa was not different from the buffer-free solution, suggesting that HCO3-stimulated JCa may be linked to acidification. To further test this hypothesis, we used 27 mM Hepes as the luminal buffer. With Hepes there was luminal fluid acidification and JCa was not different from the buffer-free solution but delta CCa was significantly reduced, indicating enhanced active calcium transport. We conclude from the results of the present study that HCO3 stimulates active Ca absorption, a process that may be linked to acidification-mediated HCO3 absorption. PMID:3366902

  17. Novel extraction induced by microemulsion breaking: a model study for Hg extraction from Brazilian gasoline.

    PubMed

    Vicentino, Priscila O; Cassella, Ricardo J

    2017-01-01

    This paper proposes a novel approach for the extraction of Hg from Brazilian gasoline samples: extraction induced by microemulsion breaking (EIMB). In this approach, a microemulsion is formed by mixing the sample with n-propanol and HCl. Afterwards, the microemulsion is destabilized by the addition of water and the two phases are separated: (i) the top phase, containing the residual gasoline and (ii) the bottom phase, containing the extracted analyte in a medium containing water, n-propanol and the ethanol originally present in the gasoline sample. The bottom phase is then collected and the Hg is measured by cold vapor atomic absorption spectrometry (CV-AAS). This model study used Brazilian gasoline samples spiked with Hg (organometallic compound) to optimize the process. Under the optimum extraction conditions, the microemulsion was prepared by mixing 8.7mL of sample with 1.2mL of n-propanol and 0.1mL of a 10molL -1 HCl solution. Emulsion breaking was induced by adding 300µL of deionized water and the bottom phase was collected for the measurement of Hg. Six samples of Brazilian gasoline were spiked with Hg in the organometallic form and recovery percentages in the range of 88-109% were observed. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Simultaneous determination of Cd and Fe in beans and soil of different regions of Brazil using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sampling.

    PubMed

    dos Santos, Lisia M G; Welz, Bernhard; Araujo, Rennan G O; Jacob, Silvana do C; Vale, Maria Goreti R; Martens, Andreas; Gonzaga Martens, Irland B; Becker-Ross, Helmut

    2009-11-11

    A fast routine screening method for the simultaneous determination of cadmium and iron in bean and soil samples is proposed, using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sampling. The primary absorption line at 228.802 nm has been used for the determination of cadmium, and an adjacent secondary line, at 228.726 nm, for iron. Fourteen bean samples and 10 soil samples from nine states all over Brazil have been analyzed. The limits of detection (3 sigma, n = 10) were 2.0 microg kg(-1) for Cd and 4.5 mg kg(-1) for Fe. The relative standard deviation ranged from 4 to 7% for Cd and from 5 to 28% for Fe, which is usually acceptable for a screening method. The accuracy of the method has been confirmed by the analysis of two certified reference materials; the results were in agreement with the certified values at a 95% confidence interval.

  19. Flow injection for the determination of Se(IV) and Se(VI) by hydride generation atomic absorption spectrometry with microwave oven on-line prereduction of Se(VI) to Se(IV)

    NASA Astrophysics Data System (ADS)

    Burguera, J. L.; Carrero, P.; Burguera, M.; Rondon, C.; Brunetto, M. R.; Gallignani, M.

    1996-12-01

    An on-line flow injection system has been developed for the selective determination of Se(IV) and Se(VI) in citric fruit juices and geothermal waters by hydride generation atomic absorption spectrometry with microwave-aided heating prereduction of Se(VI) to Se(IV). The samples and the prereductant solutions (4 mol l -1 HCl for Se(IV) and 12 mol l -1 HCl for Se(VI)) which circulated in a closed-flow circuit were injected by means of a time-based injector. This mixture was displaced by a carrier solution of 1% v/v of hydrochloric acid through a PTFE coil located inside the focused microwave oven and mixed downstream with a borohydride solution to generate the hydride. The linear ranges were 0-120 and 0-100 μg l -1 of Se(IV) and Se(VI), respectively. The detection limits were 1.0 μg l -1 for Se(IV) and 1.5 μg l -1 for Se(VI). The precision (about 2.0-2.5% RSD) and recoveries (96-98% for Se(IV) and 94-98% for Se(VI)) were good. Total selenium values were also obtained by electrothermal atomic absorption spectrometry which agreed with the content of both selenium species. The sample throughput was about 50 measurements per hour. The main advantage of the method is that the selective determination of Se(IV) and Se(VI) in citric fruit juices and geothermal waters is performed in a closed system with a minimum sample manipulation, exposure to the environment, minimum sample waste and operator attention.

  20. States' Flexibility Waiver Plans for Alternate Assessments Based on Alternate Achievement Standards (AA-AAS). Synthesis Report 96

    ERIC Educational Resources Information Center

    Lazarus, Sheryl S.; Edwards, Lynn M.; Thurlow, Martha L.; Hodgson, Jennifer R.

    2014-01-01

    All states have alternate assessments based on alternate achievement standards (AA-AAS) for students with the most significant cognitive disabilities. For accountability purposes, the Elementary and Secondary Education Act (ESEA) allows up to 1% of students to be counted as proficient with this assessment option. In 2011 the U.S. Department of…

  1. Speciation of Mn(II), Mn(VII) and total manganese in water and food samples by coprecipitation-atomic absorption spectrometry combination.

    PubMed

    Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

    2010-01-15

    A speciation procedure based on the coprecipitation of manganese(II) with zirconium(IV) hydroxide has been developed for the investigation of levels of manganese species. The determination of manganese levels was performed by flame atomic absorption spectrometry (FAAS). Total manganese was determined after the reduction of Mn(VII) to Mn(II) by ascorbic acid. The analytical parameters including pH, amount of zirconium(IV), sample volume, etc., were investigated for the quantitative recoveries of manganese(II). The effects of matrix ions were also examined. The recoveries for manganese(II) were in the range of 95-98%. Preconcentration factor was calculated as 50. The detection limit for the analyte ions based on 3 sigma (n=21) was 0.75 microg L(-1) for Mn(II). The relative standard deviation was found to be lower than 7%. The validation of the presented procedure was performed by analysis of certified reference material having different matrices, NIST SRM 1515 (Apple Leaves) and NIST SRM 1568a (Rice Flour). The procedure was successfully applied to natural waters and food samples.

  2. Proteomics analysis of altered proteins in kidney of mice with aristolochic acid nephropathy using the fluorogenic derivatization-liquid chromatography-tandem mass spectrometry method.

    PubMed

    Lin, Chia-En; Chang, Wen-Shin; Lee, Jen-Ai; Chang, Ting-Ya; Huang, Yu-Shen; Hirasaki, Yoshiro; Chen, Hung-Shing; Imai, Kazuhiro; Chen, Shih-Ming

    2018-03-01

    Aristolochic acid (AA) causes interstitial renal fibrosis, called aristolochic acid nephropathy (AAN). There is no specific indicator for diagnosing AAN, so this study aimed to investigate the biomarkers for AAN using a proteomics method. The C3H/He female mice were given ad libitum AA-distilled water (0.5 mg/kg/day) and distilled water for 56 days in the AA and normal groups, respectively. The AA-induced proteins in the kidney were investigated using a proteomics study, including fluorogenic derivatization with 7-chloro-N-[2-(dimethylamino)ethyl]-2,1,3-benzoxadiazole-4-sulfonamide, followed by high-performance liquid chromatography analysis and liquid chromatography tandem mass spectrometry with a MASCOT database searching system. There were two altered proteins, thrombospondin type 1 (TSP1) and G protein-coupled receptor 87 (GPR87), in the kidney of AA-group mice on day 56. GPR87, a tumorigenesis-related protein, is reported for the first time in the current study. The renal interstitial fibrosis was certainly induced in the AA-group mice under histological examination. Based on the results of histological examination and the proteomics study, this model might be applied to AAN studies in the future. TSP1 might be a novel biomarker for AAN, and the further role of GPR87 leading to AA-induced tumorigenesis should be researched in future studies. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Determination of trace elements in dolomite and gypsum by atomic absorption spectrometry: overcoming the matrix interference by flotation separation

    NASA Astrophysics Data System (ADS)

    Stafilov, Trajče; Zendelovska, Dragica; Pavlovska, Gorica; Čundeva, Katarina

    2002-05-01

    The interferences of Ca and Mg as matrix elements in dolomite and gypsum on Ag, Cd, Cr, Mn, Tl and Zn absorbances during their electrothermal atomic absorption spectrometric (ETAAS) determination are investigated. The results reveal that Ca and Mg do not interfere on Zn and Mn, tend to decrease absorbances of Ag, Cd and Cr, while Tl suffers the most significant influence. A flotation separation method is proposed to eliminate matrix interferences. Hydrated iron(III) oxide, Fe 2O 3· xH 2O, and iron(III) hexamethylenedithiocarbamate, Fe(HMDTC) 3, are applied as flotation collectors. The influence of hydrophobic dithiocarbamate anion, HMDTC, on flotation recoveries of each analyte is studied. The most suitable concentrations of dolomite and gypsum solutions for flotation are determined. To avoid flotation suppression due to the reaction of Ca 2+ and Mg 2+ with surfactant ions, a fit foaming agent was selected. The elements present in dolomite and gypsum as traces have been analyzed by ETAAS. Their ETAAS limits of detection following flotation are found to be 0.021 μg·g -1 for Ag, 0.019 μg·g -1 for Cd, 0.014 μg·g -1 for Cr and 0.11 μg·g -1 for Tl. The determination of Mn and Zn can be performed by flame AAS (FAAS). The limit of detection for Mn is 1.5 μg·g -1, while for Zn 0.8 μg·g -1.

  4. Differential optical absorption spectrometer for measurement of tropospheric pollutants

    NASA Astrophysics Data System (ADS)

    Evangelisti, F.; Baroncelli, A.; Bonasoni, P.; Giovanelli, G.; Ravegnani, F.

    1995-05-01

    Our institute has recently developed a differential optical absorption spectrometry system called the gas analyzer spectrometer correlating optical absorption differences (GASCOAD), which features as a detector a linear image sensor that uses an artificial light source for long-path tropospheric-pollution monitoring. The GASCOAD, its method of eliminating interference from background sky light, and subsequent spectral analysis are reported and discussed. The spectrometer was used from 7 to 22 February 1993 in Milan, a heavily polluted metropolitan area, to measure the concentrations of SO2, NO2, O3, and HNO2 averaged over a 1.7-km horizontal light path. The findings are reported and briefly discussed.

  5. Data Processing Algorithm for Diagnostics of Combustion Using Diode Laser Absorption Spectrometry.

    PubMed

    Mironenko, Vladimir R; Kuritsyn, Yuril A; Liger, Vladimir V; Bolshov, Mikhail A

    2018-02-01

    A new algorithm for the evaluation of the integral line intensity for inferring the correct value for the temperature of a hot zone in the diagnostic of combustion by absorption spectroscopy with diode lasers is proposed. The algorithm is based not on the fitting of the baseline (BL) but on the expansion of the experimental and simulated spectra in a series of orthogonal polynomials, subtracting of the first three components of the expansion from both the experimental and simulated spectra, and fitting the spectra thus modified. The algorithm is tested in the numerical experiment by the simulation of the absorption spectra using a spectroscopic database, the addition of white noise, and the parabolic BL. Such constructed absorption spectra are treated as experimental in further calculations. The theoretical absorption spectra were simulated with the parameters (temperature, total pressure, concentration of water vapor) close to the parameters used for simulation of the experimental data. Then, spectra were expanded in the series of orthogonal polynomials and first components were subtracted from both spectra. The value of the correct integral line intensities and hence the correct temperature evaluation were obtained by fitting of the thus modified experimental and simulated spectra. The dependence of the mean and standard deviation of the evaluation of the integral line intensity on the linewidth and the number of subtracted components (first two or three) were examined. The proposed algorithm provides a correct estimation of temperature with standard deviation better than 60 K (for T = 1000 K) for the line half-width up to 0.6 cm -1 . The proposed algorithm allows for obtaining the parameters of a hot zone without the fitting of usually unknown BL.

  6. AAS 227: Day 3

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    , think-pair-share style clicker questions, and comparing excerpts from scientific articles and the media. Eventually, students discover that the Earths overall temperature is going up, but observations can vary from year to year because heat is moving between the atmosphere and the oceans.Press Conference: Fermis Vision, First Stars, Massive Galaxy Cluster, and Dark Energy (by Susanna Kohler)Todays afternoon press conference was an exciting assortment of results, difficult to categorize under a single umbrella.First up was Marco Ajello (Clemson University), who spoke about 2FHL, the second Fermi-LAT catalog of high-energy sources. LAT stands for Large Area Telescope, an instrument on board the Fermi gamma-ray space observatory that scans the entire sky every three hours. Ajello described the contents of the 2FHL catalog: 360 gamma-ray sources, of which 75% are blazars (distant galactic nuclei with jets pointed toward us), 11% are sources within the galaxy, and the remaining 14% are unknown. With this catalog, Fermi has expanded into higher energies than ever before, providing the first map of the 50 GeV 2 TeV sky. Heres the press release.OMeara: Im a lowly spectroscopist so I dont have fun pictures to show you, just squiggly lines. #aas227 astrobites (@astrobites) January 7, 2016Next to speak, John OMeara (St. Michaels College) told us about the discovery of a gas cloud that may be a remnant from the first population of stars. OMeara showed us the emission spectrum from a distant quasar, which displays abrupt absorption by a cloud of gas located at a redshift of z~3.5. Absorption by gas clouds is not unusual but what is unusual is that this cloud is extremely metal-poor, with only 1/2500th solar metallicity. This is the lowest heavy-element content ever measured, and a sign that the cloud might have been enriched by Population III stars the theoretical first population of stars, which were born when gas in the universe was still pristine. Heres the press release

  7. Microsolvation of the acetanilide cation (AA(+)) in a nonpolar solvent: IR spectra of AA(+)-L(n) clusters (L = He, Ar, N2; n ≤ 10).

    PubMed

    Schmies, Matthias; Patzer, Alexander; Schütz, Markus; Miyazaki, Mitsuhiko; Fujii, Masaaki; Dopfer, Otto

    2014-05-07

    Infrared photodissociation (IRPD) spectra of mass-selected cluster ions of acetanilide (N-phenylacetamide), AA(+)-Ln, with the ligands L = He (n = 1-2), Ar (n = 1-7), and N2 (n = 1-10) are recorded in the hydride stretch (amide A, νNH, νCH) and fingerprint (amide I-III) ranges of AA(+) in its (2)A'' ground electronic state. Cold AA(+)-Ln clusters are generated in an electron impact ion source, which predominantly produces the most stable isomer of a given cluster ion. Systematic vibrational frequency shifts of the N-H stretch fundamentals (νNH) provide detailed information about the sequential microsolvation process of AA(+) in a nonpolar (L = He and Ar) and quadrupolar (L = N2) solvent. In the most stable AA(+)-Ln clusters, the first ligand forms a hydrogen bond (H-bond) with the N-H proton of trans-AA(+) (t-AA(+)), whereas further ligands bind weakly to the aromatic ring (π-stacking). There is no experimental evidence for complexes with the less stable cis-AA(+) isomer. Quantum chemical calculations at the M06-2X/aug-cc-pVTZ level confirm the cluster growth sequence derived from the IR spectra. The calculated binding energies of De(H) = 720 and 1227 cm(-1) for H-bonded and De(π) = 585 and 715 cm(-1) for π-bonded Ar and N2 ligands in t-AA(+)-L are consistent with the observed photofragmentation branching ratios of AA(+)-Ln. Comparison between charged and neutral AA((+))-L dimers indicates that ionization switches the preferred ion-ligand binding motif from π-stacking to H-bonding. Electron removal from the HOMO of AA(+) delocalized over both the aromatic ring and the amide group significantly strengthens the C[double bond, length as m-dash]O bond and weakens the N-H bond of the amide group.

  8. The Pasadena Recommendations: Five Years After AAS Endorsement

    NASA Astrophysics Data System (ADS)

    Knezek, Patricia; Frattare, L.; Ulvestad, J.

    2010-01-01

    It has been five years since the AAS Council unanimously endorsed the document, known as "Equity Now: The Pasadena Recommendations for Gender Equality in Astronomy," in January 2005. This document was the main product of the conference entitled "Women in Astronomy II: Ten Years After” (WIA II), held in June 2003 in Pasadena, CA. Participants of that 2003 meeting assessed the progress for women in science, offering insights into causes of the slower advancement of women, and discussed strategies to accelerate the achievement of equality. These insights and strategies were then incorporated into the "Pasadena Recommendations" by the CSWA. It was subsequently released to the entire AAS community for review and comments prior to its endorsement by the AAS. We will discuss the Recommendations and their impact since the endorsement by the AAS, including the process that is in place for organizations and departments to formally endorse the Pasadena Recommendations, thus making an organizational commitment to their implementation (see http://www.aas.org/cswa/pasadena_endorse.html).

  9. [Exposure to metal compounds in occupational galvanic processes].

    PubMed

    Surgiewicz, Jolanta; Domański, Wojciech

    2006-01-01

    Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

  10. Evaluation of a new optic-enabled portable X-ray fluorescence spectrometry instrument for measuring toxic metals/metalloids in consumer goods and cultural products

    NASA Astrophysics Data System (ADS)

    Guimarães, Diana; Praamsma, Meredith L.; Parsons, Patrick J.

    2016-08-01

    X-ray fluorescence spectrometry (XRF) is a rapid, non-destructive multi-elemental analytical technique used for determining elemental contents ranging from percent down to the μg/g level. Although detection limits are much higher for XRF compared to other laboratory-based methods, such as inductively coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectrometry (OES) and atomic absorption spectrometry (AAS), its portability and ease of use make it a valuable tool, especially for field-based studies. A growing necessity to monitor human exposure to toxic metals and metalloids in consumer goods, cultural products, foods and other sample types while performing the analysis in situ has led to several important developments in portable XRF technology. In this study, a new portable XRF analyzer based on the use of doubly curved crystal optics (HD Mobile®) was evaluated for detecting toxic elements in foods, medicines, cosmetics and spices used in many Asian communities. Two models of the HD Mobile® (a pre-production and a final production unit) were investigated. Performance parameters including accuracy, precision and detection limits were characterized in a laboratory setting using certified reference materials (CRMs) and standard solutions. Bias estimates for key elements of public health significance such as As, Cd, Hg and Pb ranged from - 10% to 11% for the pre-production, and - 14% to 16% for the final production model. Five archived public health samples including herbal medicine products, ethnic spices and cosmetic products were analyzed using both XRF instruments. There was good agreement between the pre-production and final production models for the four key elements, such that the data were judged to be fit-for-purpose for the majority of samples analyzed. Detection of the four key elements of interest using the HD Mobile® was confirmed using archived samples for which ICP-OES data were available based on digested sample materials. The HD

  11. Multiple Absorption Components in the Post-Periastron He I P Cygni Absorption Troughs of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Richardson, Noel D.; Damineli, Augusto; Gull, Ted; Moffat, Anthony; Groh, Jose; St.-Jean, Lucas; Walter, Frederick M.; Teodoro, Mairan; Madura, Tom; Corcoran, Michael; hide

    2015-01-01

    We have obtained more than 100 high spectral resolution (R approx. 90,000) spectra of the massive binary star eta Carinae since 2012 in an effort to continue our orbital and long-term echelle monitoring of this extreme binary (Richardson et al. 2010, AJ, 139, 1534) with the CHIRON spectrograph on the CTIO 1.5 m telescope (Tokovinin et al. 2013, PASP, 125, 1336) in the 4550-7500A region. We increased our monitoring efforts and observation frequency as the periastron event of 2014 has approached, and resumed observations in October. We note that since mid-October, we have observed unusual multiple absorption components in the P Cygni troughs of the He I lines (4714, 5876, 6678, and 7065; 4921 and 5015 are blended with Fe II). In particular, we note that these components extend to -700 km/s, well beyond the terminal wind speed of the primary. These absorptions are likely related to clumps and turbulence in the wind-wind collision region and bow shock, as suggested by the high-velocity absorption observed by Groh et al. (2010, A&A, 519, 9) in the He I 10830A transition and our pre-periastron observations (Richardson et al. 2014, ATel #6336). In these cases, we suspect that we look along an arm of the shock cone and that we see a fast absorption change from the other collision region shortly after periastron. Further, high spectral resolution data are highly encouraged, especially for resolving powers greater than 50,000. These observations were obtained with the CTIO 1.5 m telescope, operated by the SMARTS Consortium, and were obtained through both SMARTS and NOAO programs 2012A-0216, 2012B-0194, and 2013b-0328. We thank Emily MacPherson (Yale) for her efforts in scheduling the observations that we have and will obtain in the coming weeks and months.

  12. Single-Walled Carbon Nanotubes (SWCNTs), as a Novel Sorbent for Determination of Mercury in Air

    PubMed Central

    Golbabaei, Farideh; Ebrahimi, Ali; Shirkhanloo, Hamid; Koohpaei, Alireza; Faghihi-Zarandi, Ali

    2016-01-01

    Background: Based on the noticeable toxicity and numerous application of mercury in industries, removal of mercury vapor through sorbent is an important environmental challenge. Purpose of the Study: Due to their highly porous and hollow structure, large specific surface area, light mass density and strong interaction, Single-Walled Carbon Nanotubes (SWCNTs) sorbent were selected for this investigation. Methods: In this study, instrumental conditions, method procedure and different effective parameters such as adsorption efficiency, desorption capacity, time, temperature and repeatability as well as retention time of adsorbed mercury were studied and optimized. Also, mercury vapor was determined by cold vapor atomic absorption spectrometry (CV-AAS). Obtained data were analyzed by Independent T- test, Multivariate linear regression and one way–ANOVA finally. Results: For 80 mg nanotubes, working range of SWCNT were achieved 0.02-0.7 μg with linear range (R2=0.994). Our data revealed that maximum absorption capacity was 0.5 μg g-1 as well as limit of detection (LOD) for studied sorbent was 0.006 μg. Also, optimum time and temperature were reported, 10 min and 250 °C respectively. Retention time of mercury on CNTs for three weeks was over 90%. Results of repeated trials indicated that the CNTs had long life, so that after 30 cycles of experiments, efficiency was determined without performance loss. Conclusion: Results showed that carbon nanotubes have high potential for efficient extraction of mercury from air and can be used for occupational and environmental purposes. The study of adsorption properties of CNTs is recommended. PMID:26925918

  13. [Determination of sulfur in plant using a high-resolution continuum source atomic absorption spectrometer].

    PubMed

    Wang, Yu; Li, Jia-xi

    2009-05-01

    A method for the analysis of sulfur (S) in plant by molecular absorption of carbon monosulfide (CS) using a high-resolution continuum source atomic absorption spectrometer (CS AAS) with a fuel-rich air/acetylene flame has been devised. The strong CS absorption band was found around 258 nm. The half-widths of some absorption bands were of the order of picometers, the same as the common atomic absorption lines. The experimental procedure in this study provided optimized instrumental conditions (the ratio of acetylene to air, the burner height) and parameters, and researched the spectral interferences and chemical interferences. The influence of the organic solvents on the CS absorption signals and the different digestion procedures for the determination of sulfur were also investigated. The limit of detection achieved for sulfur was 14 mg x L(-1), using the CS wavelength of 257. 961 nm and a measurement time of 3 s. The accuracy and precision were verified by analysis of two plant standard reference materials. The major applications of this method have been used for the determination of sulfur in plant materials, such as leaves. Compared to the others, this method for the analysis of sulfur is rapid, easy and simple for sulfur determination in plant.

  14. Characteristics of AA amyloidosis patients in San Francisco.

    PubMed

    Lejmi, Hiba; Jen, Kuang-Yu; Olson, Jean L; James, Sam H; Sam, Ramin

    2016-04-01

    AA amyloidosis due to subcutaneous injection of drugs of abuse has been described in the USA, but all the existing literature is from more than 20 years ago. There is more recent literature from Europe. We have observed a high incidence of AA amyloidosis in the county hospital in San Francisco. Here, we describe 24 patients who had kidney biopsy-proven AA amyloidosis from our hospital from 1998 to 2013. All the patients were thought to have AA amyloidosis from skin popping of illicit drugs after having exhausted the intravenous route. These patients with biopsy-proven AA amyloidosis were analysed further. All patients were found to have hepatitis C infection, hypertension was not common, most had advanced kidney failure, and acidosis was common as was tubulointerstitial involvement on the kidney biopsy. Other organ involvement included hepatomegaly and splenomegaly in a number of patients; direct myocardial involvement was not seen, but pulmonary hypertension, history of deep vein thrombosis and pulmonary embolism were common. The prognosis of these patients was poor. The mortality rate approached 50% 1 year after biopsy, and most of the patient needed dialysis shortly after diagnosis. Cessation of drug use seemed beneficial but rarely achievable. AA amyloidosis from skin popping is common in San Francisco. Most patients with renal involvement end up on dialysis, and mortality rates are exceedingly high. © 2015 Asian Pacific Society of Nephrology.

  15. Quantifying uncertainty in measurement of mercury in suspended particulate matter by cold vapor technique using atomic absorption spectrometry with hydride generator.

    PubMed

    Singh, Nahar; Ahuja, Tarushee; Ojha, Vijay Narain; Soni, Daya; Tripathy, S Swarupa; Leito, Ivo

    2013-01-01

    As a result of rapid industrialization several chemical forms of organic and inorganic mercury are constantly introduced to the environment and affect humans and animals directly. All forms of mercury have toxic effects; therefore accurate measurement of mercury is of prime importance especially in suspended particulate matter (SPM) collected through high volume sampler (HVS). In the quantification of mercury in SPM samples several steps are involved from sampling to final result. The quality, reliability and confidence level of the analyzed data depends upon the measurement uncertainty of the whole process. Evaluation of measurement uncertainty of results is one of the requirements of the standard ISO/IEC 17025:2005 (European Standard EN IS/ISO/IEC 17025:2005, issue1:1-28, 2006). In the presented study the uncertainty estimation in mercury determination in suspended particulate matter (SPM) has been carried out using cold vapor Atomic Absorption Spectrometer-Hydride Generator (AAS-HG) technique followed by wet chemical digestion process. For the calculation of uncertainty, we have considered many general potential sources of uncertainty. After the analysis of data of seven diverse sites of Delhi, it has been concluded that the mercury concentration varies from 1.59 ± 0.37 to 14.5 ± 2.9 ng/m(3) with 95% confidence level (k = 2).

  16. Viable, lyophilized lactobacilli do not increase iron absorption from a lactic acid-fermented meal in healthy young women, and no iron absorption occurs in the distal intestine.

    PubMed

    Bering, Stine; Sjøltov, Laila; Wrisberg, Seema S; Berggren, Anna; Alenfall, Jan; Jensen, Mikael; Højgaard, Liselotte; Tetens, Inge; Bukhave, Klaus

    2007-11-01

    Lactic acid-fermented foods have been shown to increase Fe absorption in human subjects, possibly by lowering pH, activation of phytases, production of organic acids, or by the viable lactic acid bacteria. In this study the effect of a heat-inactivated lactic acid-fermented oat gruel with and without added viable, lyophilized Lactobacillus plantarum 299v on non-haem Fe absorption was investigated. Furthermore, Fe absorption in the distal intestine was determined. In a randomized, double-blinded crossover trial eighteen healthy young women aged 22 (SD 3) years with low Fe status (serum ferritin < 30 microg/l) were served the two test gruels, extrinsically labelled with 59Fe and served with two enterocoated capsules (containing 55Fe(II) and 55Fe(III), respectively) designed to disintegrate in the ileum. The meals were consumed on two consecutive days, e.g. in the order AA followed by BB in a second period. Non-haem Fe absorption was determined from 59Fe whole-body retention and isotope activities in blood samples. The concentrations of Fe, lactate, phytate, and polyphenols, and the pH were similar in the heat-inactivated lactic acid-fermented oat gruels with and without added L. plantarum 299v, and no difference in Fe absorption was observed between the test gruels (1.4 and 1.3%, respectively). Furthermore, no absorption of Fe in the distal intestine was observed. In conclusion, addition of viable, lyophilized lactobacillus to a heat-inactivated lactic acid-fermented oat gruel does not affect Fe absorption, and no absorption seems to occur in the distal part of the intestine from low Fe bioavailability meals in these women.

  17. Solid-phase extraction and separation procedure for trace aluminum in water samples and its determination by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS).

    PubMed

    Ciftci, Harun; Er, Cigdem

    2013-03-01

    In the present study, a separation/preconcentration procedure for determination of aluminum in water samples has been developed by using a new atomic absorption spectrometer concept with a high-intensity xenon short-arc lamp as continuum radiation source, a high-resolution double-echelle monochromator, and a charge-coupled device array detector. Sample solution pH, sample volume, flow rate of sample solution, volume, and concentration of eluent for solid-phase extraction of Al chelates with 4-[(dicyanomethyl)diazenyl] benzoic acid on polymeric resin (Duolite XAD-761) have been investigated. The adsorbed aluminum on resin was eluted with 5 mL of 2 mol L(-1) HNO(3) and its concentration was determined by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Under the optimal conditions, limit of detection obtained with HR-CS FAAS and Line Source FAAS (LS-FAAS) were 0.49 μg L(-1) and 3.91 μg L(-1), respectively. The accuracy of the procedure was confirmed by analyzing certified materials (NIST SRM 1643e, Trace elements in water) and spiked real samples. The developed procedure was successfully applied to water samples.

  18. Comparative Effectiveness of Ranolazine Versus Traditional Therapies in Chronic Stable Angina Pectoris and Concomitant Diabetes Mellitus and Impact on Health Care Resource Utilization and Cardiac Interventions.

    PubMed

    Page, Robert L; Ghushchyan, Vahram; Read, Richard A; Hartsfield, Cynthia L; Koch, Bruce R; Nair, Kavita V

    2015-11-01

    Comparative studies evaluating traditional versus newer antianginal (AA) medications in chronic stable angina pectoris (CSA) on cardiovascular (CV) outcomes and utilization are limited, particularly in patients with diabetes mellitus (DM). Claims data (2008 to 2012) were analyzed using a commercial database. Patients with CSA receiving a β blocker (BB), calcium channel blocker (CCB), long-acting nitrate (LAN), or ranolazine were identified and followed for 12 months after a change in AA therapy. Patients on traditional AA medications were required to have concurrent sublingual nitroglycerin. Therapy change was defined as adding or switching to another traditional AA medication or ranolazine to identify patients whose angina was inadequately controlled with previous therapy. Four groups were identified (BB, CCB, LAN, or ranolazine users) and matched on relevant characteristics. A DM subset was identified. Logistic regression compared revascularization at 30, 60, 90, 180, and 360 days. Negative binomial regression compared all-cause, CV-, and DM-related (in the DM cohort) health care utilization. A total of 8,008 patients were identified with 2,002 patients in each matched group. Majority were men (mean age 66 years). A subset of 3,724 patients with DM (BB, n = 933; CCB, n = 940; LAN, n = 937; and ranolazine, n = 914) resulted from this cohort. Compared to ranolazine in the overall cohort, traditional AA medication exhibited greater odds for revascularization and higher rates in all-cause outpatient, emergency room visits, inpatient length of stay, and CV-related emergency room visits. In the DM cohort, ranolazine demonstrated similar benefits over traditional AA medication. In conclusion, ranolazine use in patients with inadequately controlled chronic angina is associated with less revascularization and all-cause and CV-related health care utilization compared to traditional AA medication. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. CV-990 LSRA

    NASA Image and Video Library

    1992-05-27

    A NASA CV-990, modified as a Landing Systems Research Aircraft (LSRA), is serviced on the ramp at NASA's Dryden Flight Research Center, Edwards, California, before a test of the space shuttle landing gear system. The space shuttle landing gear test unit, operated by a high-pressure hydraulic system, allowed engineers to assess and document the performance of space shuttle main and nose landing gear systems, tires and wheel assemblies, plus braking and nose wheel steering performance. The series of 155 test missions for the space shuttle program provided extensive data about the life and endurance of the shuttle tire systems and helped raise the shuttle crosswind landing limits at Kennedy.

  20. MDCT evaluation of acute aortic syndrome (AAS)

    PubMed Central

    Rossi, Giovanni; Lassandro, Francesco; Rea, Gaetano; Marino, Maurizio; Muto, Maurizio; Molino, Antonio; Scaglione, Mariano

    2016-01-01

    Non-traumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. There is a common pathway for the various manifestations of AAS that eventually leads to a breakdown of the aortic intima and media. Improvements in biology and health policy and diffusion of technology into the community resulted in an associated decrease in mortality and morbidity related to aortic therapeutic interventions. Hybrid procedures, branched and fenestrated endografts, and percutaneous aortic valves have emerged as potent and viable alternatives to traditional surgeries. In this context, current state-of-the art multidetector CT (MDCT) is actually the gold standard in the emergency setting because of its intrinsic diagnostic value. Management of acute aortic disease has changed with the increasing realization that endovascular therapies may offer distinct advantages in these situations. This article provides a summary of AAS, focusing especially on the MDCT technique, typical and atypical findings and common pitfalls of AAS, as well as recent concepts regarding the subtypes of AAS, consisting of aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and unstable aortic aneurysm or contained aortic rupture. MDCT findings will be related to pathophysiology, timing and management options to achieve a definite and timely diagnostic and therapeutic definition. In the present article, we review the aetiology, pathophysiology, clinical presentation, outcomes and therapeutic approaches to acute aortic syndromes. PMID:27033344

  1. The simultaneous electrochemical detection of ascorbic acid, dopamine, and uric acid using graphene/size-selected Pt nanocomposites.

    PubMed

    Sun, Chia-Liang; Lee, Hsin-Hsien; Yang, Jen-Ming; Wu, Ching-Chou

    2011-04-15

    In this study, a graphene/Pt-modified glassy carbon (GC) electrode was created to simultaneously characterize ascorbic acid (AA), dopamine (DA), and uric acid (UA) levels via cyclic voltammetry (CV) and differential pulse voltammetry (DPV). During the preparation of the nanocomposite, size-selected Pt nanoparticles with a mean diameter of 1.7 nm were self-assembled onto the graphene surface. In the simultaneous detection of the three aforementioned analytes using CV, the electrochemical potential differences among the three detected peaks were 185 mV (AA to DA), 144 mV (DA to UA), and 329 mV (AA and UA), respectively. In comparison to the CV results of bare GC and graphene-modified GC electrodes, the large electrochemical potential difference that is achieved via the use of the graphene/Pt nanocomposites is essential to the distinguishing of these three analytes. An optimized adsorption of size-selected Pt colloidal nanoparticles onto the graphene surface results in a graphene/Pt nanocomposite that can provide a good platform for the routine analysis of AA, DA, and UA. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Nonlinear absorption of short intense laser pulse in multispecies plasma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kargarian, A.; Hajisharifi, K.; Mehdian, H.

    In the present paper, the detailed investigation concerning the effect of inclusion of heavy negative ions into the finite background plasma on the laser absorption has been carried out by employing particle-in-cell simulation method. For this purpose, in this configuration, the laser energy absorption relying on the nonlinear phenomena such as phase-mixing, wave-breaking, and scattering has been studied in the Raman-Brillouin regime. It is shown that the inclusion of heavy negative ions suppresses the scattering while increases the phase-mixing time. Moreover, it is illustrated that this inclusion can increase the laser absorption in finite plasma environment, after saturation. The obtainedmore » results are expected to be relevant to the experiments on the mass spectrometry with laser desorption techniques as well as on the laser-plasma interaction with application to particles acceleration.« less

  3. Reinforcement with alumina particles at the interface region of AA6101-T6 and AA1350 alloys during friction stir welding

    NASA Astrophysics Data System (ADS)

    Ashok Kumar, R.; Thansekhar, M. R.

    2018-04-01

    This paper deals the combinational effect of friction stir welding and friction stir processing on dissimilar AA6101-T6 and AA1350 aluminium alloys. For that, alumina particles are reinforced at interface region of AA6101-T6 and AA1350 aluminium alloys. Friction Stir Welding and Friction Stir Processing are done simultaneously for various sizes of groove. To analyze the welding quality and surface modifications, mechanical, wear and microstructural tests are carried out. Among these, smallest groove of 0.5 mm width and 1 mm depth reveals highest tensile and bending strengths and largest groove of 2 mm width and 3 mm depth gives maximum hardness and wear resistance. Taguchi technique shows that groove width is most influencing parameter. Developed second order models with interaction predict the responses with minimum error.

  4. So you want to be a specialist registrar?--What to put in your CV.

    PubMed

    Ellis, P E; Ellis, S G S; O'Brien, K D; Joshi, R I

    2002-02-09

    Dentists applying to a specialist training programme often receive conflicting advice over what to put in their curriculum vitae (CV). We conducted a survey of the Training Programme Directors of the dental specialties to determine what aspects of CV content and presentation styles are considered important. This has allowed us to construct guidelines for what to put in a CV. Recently, structured application forms have become increasingly popular and may be a more objective way to carry out the shortlisting process. The guidelines presented could also be used as a framework for medical personnel departments if structured application forms eventually replace the CV.

  5. Comparison of calculated and experimentally determined SID of CP and AA in complex diets differing in AA contents for grower finisher pigs.

    PubMed

    Büsing, K; Berk, A; Müller, S; Kieckhäven, S; Krüger, K; Zeyner, A

    2017-10-01

    In practice, the content of standardized ileal digestible AA in complex feeds for pigs is calculated on the basis of tabulated values for individual feedstuffs. It comes into question, however, whether this truly reflects an accurate content based upon the estimate made for the individual feedstuffs. The objective of this study was to compare standardized ileal digestibility (SID) of crude protein (CP) and selected AA in complex feeds for grower and finisher pigs either calculated or experimentally determined. Six diets with increasing AA levels were prepared for grower (BW from 30 to 70 kg) and finisher (BW from 70 to 120 kg) feed. Crystalline L-lys, DL-met and L-thr were added to both diets, L-trp and L-val only to the grower feed. SID of both CP and AA was calculated from feed tables and experimentally determined in six adult minipigs (MINILEWE) with ileorectal anastomosis. With increasing AA levels, experimentally determined SID of supplemented AA increased (p < 0.05), but SID of CP (p ≥ 0.05) was not affected. In both grower and finisher feed, calculated and experimentally determined SID of CP, Met, Cys, Trp, Ile and Tyr differed by more than 2% units, but those of Lys and His only in the finisher feed. Yet this effect was not directly consistent. The margin of error following estimation of SID of AA via tabulated values for individual feedstuffs, however, seems to be acceptable for practical use. Journal of Animal Physiology and Animal Nutrition © 2017 Blackwell Verlag GmbH.

  6. Segmentation of kidney using C-V model and anatomy priors

    NASA Astrophysics Data System (ADS)

    Lu, Jinghua; Chen, Jie; Zhang, Juan; Yang, Wenjia

    2007-12-01

    This paper presents an approach for kidney segmentation on abdominal CT images as the first step of a virtual reality surgery system. Segmentation for medical images is often challenging because of the objects' complicated anatomical structures, various gray levels, and unclear edges. A coarse to fine approach has been applied in the kidney segmentation using Chan-Vese model (C-V model) and anatomy prior knowledge. In pre-processing stage, the candidate kidney regions are located. Then C-V model formulated by level set method is applied in these smaller ROI, which can reduce the calculation complexity to a certain extent. At last, after some mathematical morphology procedures, the specified kidney structures have been extracted interactively with prior knowledge. The satisfying results on abdominal CT series show that the proposed approach keeps all the advantages of C-V model and overcome its disadvantages.

  7. Mercury(II) and methyl mercury determinations in water and fish samples by using solid phase extraction and cold vapour atomic absorption spectrometry combination.

    PubMed

    Tuzen, Mustafa; Karaman, Isa; Citak, Demirhan; Soylak, Mustafa

    2009-07-01

    A method has been developed for mercury(II) and methyl mercury speciation on Staphylococcus aureus loaded Dowex Optipore V-493 micro-column in the presented work, by using cold vapour atomic absorption spectrometry. Selective and sequential elution with 0.1 molL(-1) HCl for methyl mercury and 2 molL(-1) HCl for mercury(II) were performed at the pH range of 2-6. Optimal analytical conditions including pH, amounts of biosorbent, sample volumes were investigated. The detection limits of the analytes were 2.5 ngL(-1) for Hg(II) and 1.7 ngL(-1) for methyl mercury. The capacity of biosorbent for mercury(II) and methyl mercury was 6.5 and 5.4 mgg(-1), respectively. The validation of the presented procedure is performed by the analysis of standard reference material. The speciation procedure established was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and microwave digested fish samples.

  8. Multiwalled carbon nanotubes as a sorbent material for the solid phase extraction of lead from urine and subsequent determination by electrothermal atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Peña Crecente, Rosa M.; Lovera, Carlha Gutiérrez; García, Julia Barciela; Méndez, Jennifer Álvarez; Martín, Sagrario García; Latorre, Carlos Herrero

    2014-11-01

    The determination of lead in urine is a way of monitoring the chemical exposure to this metal. In the present paper, a new method for the Pb determination by electrothermal atomic absorption spectrometry (ETAAS) in urine at low levels has been developed. Lead was separated from the undesirable urine matrix by means of a solid phase extraction (SPE) procedure. Oxidized multiwalled carbon nanotubes have been used as a sorbent material. Lead from urine was retained at pH 4.0 and was quantitatively eluted using a 0.7 M nitric acid solution and was subsequently measured by ETAAS. The effects of parameters that influence the adsorption-elution process (such as pH, eluent volume and concentration, sampling and elution flow rates) and the atomic spectrometry conditions have been studied by means of different factorial design strategies. Under the optimized conditions, the detection and quantification limits obtained were 0.08 and 0.26 μg Pb L- 1, respectively. The results demonstrate the absence of a urine matrix effect and this is the consequence of the SPE process carried out. Therefore, the developed method is useful for the analysis of Pb at low levels in real samples without the influence of other urine components. The proposed method was applied to the determination of lead in urine samples of unexposed healthy people and satisfactory results were obtained (in the range 3.64-22.9 μg Pb L- 1).

  9. AstroCV: Astronomy computer vision library

    NASA Astrophysics Data System (ADS)

    González, Roberto E.; Muñoz, Roberto P.; Hernández, Cristian A.

    2018-04-01

    AstroCV processes and analyzes big astronomical datasets, and is intended to provide a community repository of high performance Python and C++ algorithms used for image processing and computer vision. The library offers methods for object recognition, segmentation and classification, with emphasis in the automatic detection and classification of galaxies.

  10. [Determination of trace cobalt in human urine by graphite furnace atomic absorption spectrometr].

    PubMed

    Zhong, L X; Ding, B M; Jiang, D; Liu, D Y; Yu, B; Zhu, B L; Ding, L

    2016-05-20

    To establish a method to determine cobalt in human urine by graphite furnace atomic absorption spectrometry. Urine with 2% nitric acid diluted two-fold, to quantify the curve, graphite furnace atomic absorption spectrometric detection. Co was linear within 2.5~40.0 ng/ml with r>0.999. Spike experiment showed that Co received good recovery rate, which was 90.8%~94.8%. Intra-assay precisions were 3.2%~5.1% for Co, inter-assay precisions were 4.4%~5.2% for Co. The method by using graphite furnace atomic absorption spectrometr to determine urine Co was fast, accurate and with low matrix effect. It could meet the requirement in GBZ/T 210.5-2008.

  11. A New CV3 Chondrite Find

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.; Dehart, J. M.

    1992-07-01

    A new meteorite find from West Texas, U.S.A., is a CV3 carbonaceous chondrite. The provisional name of Red Bluff has been proposed to the Nomenclature Committee by R. Farrell. Red Bluff consists of chondrules (56.4%), CAIs (8.3%), amoboid olivine aggregates (0.6%), mineral fragments (0.8%), and Ca-Al chondrules (0.4%) in a fine-grained, clay-rich matrix (33.1%). Chondrules in Red Bluff are spherical to irregular in shape, and from 0.25-3.5 mm diameter in thin section; the average diameter is 0.95 mm, with standard deviation of 0.6 mm (69 chondrules). Three of the chondrules are distinctly larger than the rest; without these three, the average diameter is 0.86 mm (s.d. 0.4 mm). The chondrules are almost all of type I (Fe-poor), as shown by cathodoluminescence and chemical analyses; most are also rich in opaques. Compositions of chondrule olivines average Fa1.9+-1.2 (s.d.); compositions of chondrule pyroxenes average Fs3.4+-3.3 (s.d.). Chondrule varieties include porphyritic olivine, microporphyritic olivine, granular olivine, macroporphyritic olivine, barred olivine, and rare extracentroradial pyroxene (0.25 mm diam.) [1,2]. Two calcium-aluminum chondrules were observed. The largest, 1.5 mm diam., contains spinel, plagioclase, and fassaite, and includes a circular spinel palisade [3]. The other Ca-Al chondrule is within a coarse-grained CAI, and could also be a well-developed spinel palisade [3]. Fine- and coarse-grained CAIs are present but have been studied little; most appear to be type B (melilite+pyroxene+plagioclase). Red Bluff's matrix is composed of fine-grained clay, with minor olivine, "limonite," troilite, and Fe metal. Alignment of grains and oxide-rich streaks in the matrix mark a planar fabric that wraps around chondrules and inclusions. Chondrules are commonly surrounded by shells of dark red alteration, darker than the bulk of matrix material. Red Bluff is weathered. It is stained red by oxidized iron minerals, which are most common as veinlets

  12. Determining the arsenic, cadmium, lead, copper and chromium contents by atomic absorption spectrometry in Pangasius fillets from Vietnam.

    PubMed

    Molognoni, Luciano; Vitali, Luciano; Ploêncio, Leandro As; Santos, Jacson N; Daguer, Heitor

    2016-07-01

    Pangasius is a fish produced on a large scale in Vietnam and exported to many countries. Since river contamination from human activities can affect the safety of this food, fish consumption can cause exposure to potentially toxic elements for humans. The aim of this study, therefore, was to assess arsenic, cadmium, lead, copper and chromium contents by atomic absorption spectrometry in Pangasius fillet produced in the provinces of Dong Thap and Can Tho (Vietnam) and exported to Brazil. The limits of detection were: arsenic 0.5443 µg kg(-1) , cadmium 0.0040 mg kg(-1) , chromium 0.0004 mg kg(-1) , copper 0.0037 mg kg(-1) and lead 0.0284 mg kg(-1) . Analysis of 20 samples showed results below the limit of detection for arsenic, chromium and lead, while copper average concentration was 0.0234 mg kg(-1) . Cadmium average concentration was 0.0547 mg kg(-1) , with no significant difference between the two regions studied. The samples of Pangasius had no detectable concentrations of arsenic, chromium, copper and lead, and do not represent a hazard to public health. However, cadmium analysis revealed non-compliant samples, demonstrating the importance of monitoring the quality of imported Pangasius fish. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  13. Validation of a hydride generation atomic absorption spectrometry methodology for determination of mercury in fish designed for application in the Brazilian national residue control plan.

    PubMed

    Damin, Isabel C F; Santo, Maria A E; Hennigen, Rosmari; Vargas, Denise M

    2013-01-01

    In the present study, a method for the determination of mercury (Hg) in fish was validated according to ISO/IEC 17025, INMETRO (Brazil), and more recent European recommendations (Commission Decision 2007/333/EC and 2002/657/EC) for implementation in the Brazilian Residue Control Plan (NRCP) in routine applications. The parameters evaluated in the validation were investigated in detail. The results obtained for limit of detection and quantification were respectively, 2.36 and 7.88 μg kg(-1) of Hg. While the recovery varies between 90-96%. The coefficient of variation was of 4.06-8.94% for the repeatability. Furthermore, a comparison using an external proficiency testing scheme was realized. The results of method validated for the determination of the mercury in fish by Hydride generation atomic absorption spectrometry were considered suitable for implementation in routine analysis.

  14. Etalon-induced Baseline Drift And Correction In Atom Flux Sensors Based On Atomic Absorption Spectroscopy

    DOE PAGES

    Du, Yingge; Chambers, Scott A.

    2014-10-20

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific, real-time flux sensing and control. The ultimate sensitivity and performance of the sensors are strongly affected by the long-term and short term baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability which has not been previously considered or corrected by existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5%,more » which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.« less

  15. [Habitat factor analysis for Torreya grandis cv. Merrillii based on spatial information technology].

    PubMed

    Wang, Xiao-ming; Wang, Ke; Ao, Wei-jiu; Deng, Jin-song; Han, Ning; Zhu, Xiao-yun

    2008-11-01

    Torreya grandis cv. Merrillii, a tertiary survival plant, is a rare tree species of significant economic value and expands rapidly in China. Its special habitat factor analysis has the potential value to provide guide information for its planting, management, and sustainable development, because the suitable growth conditions for this tree species are special and strict. In this paper, the special habitat factors for T. grandis cv. Merrillii in its core region, i.e., in seven villages of Zhuji City, Zhejiang Province were analyzed with Principal Component Analysis (PCA) and a series of data, such as IKONOS image, Digital Elevation Model (DEM), and field survey data supported by the spatial information technology. The results showed that T. grandis cv. Merrillii exhibited high selectivity of environmental factors such as elevation, slope, and aspect. 96.22% of T. grandis cv. Merrillii trees were located at the elevation from 300 to 600 m, 97.52% of them were found to present on the areas whose slope was less than 300, and 74.43% of them distributed on sunny and half-sunny slopes. The results of PCA analysis indicated that the main environmental factors affecting the habitat of T. grandis cv. Merrillii were moisture, heat, and soil nutrients, and moisture might be one of the most important ecological factors for T. grandis cv. Merrillii due to the unique biological and ecological characteristics of the tree species.

  16. [Effect of electroacupuncture at Zhongwan(CV 12) on skin microcirculatory blood perfusion units along the conception vessel in yang-deficiency volunteers].

    PubMed

    Shen, Cimin; Xu, Jinsen; Zheng, Shuxia; Lin, Lijiao; Yang, Xiaomei; Liu, Chunlan

    2016-02-01

    To observe the effect of electroacupuncture(EA) at Zhongwan(CV 12) on the energy metabolism along the conception vessel(CV) in volunteers with yang-deficiency constitution,and to explore the relationship of electroacupuncture regulation and body constitution. Eighteen volunteers with mild constitution and 18 volunteers with yang-deficiency constitution were collected out of 200 students of Fujian University of TCM by body constitution questionnaire. Skin microcirculatory blood perfusion units (MBPU) at Danzhong (CV 17), Xiawan(CV 10) and Qihai(CV 6) of CV were measured by a laser Doppler flowmetry in the normal condition and after EA stimulation at Zhongwan(CV 12) for 20 min. (1)Before treatment, (1)MBPU values at Danzhong(CV 17), Xiawan(CV 10) and Qihai(CV 6) in the yang-deficiency constitution group were lower than those in the mild constitution group,but there was no statistical significance (both P>0. 05) except Danzhong(CV 17) (P<0. 01). (Z)As for the three acupoints in the mild constitution group, MBPU level of Danzhong(CV 17) was higher than that of Xiawan(CV 10) without statistical significance(P->0. 05),and MBPU values of Danzhong(CV 17) and Xiawan(CV 10) were higher than that of Qihai(CV 6) (both P<0. 01). (3About the three acupoints in the yang-deficiency constitution group, MBPU result of Danzhong(CV 17) was lower than the value of Xiawan(CV 10), but higher compared with Qihai(CV 6)(P<0. 05, P<0. 01). MBPU of Xiawan(CV 10) was higher than Qihai (CV 6) as well(P<0. 01). (2) MBPU values of Danzhong(CV 17), Xiawan(CV 10) and Qihai(CV 6) were increased apparently compared with those before treatment after EA stimulation at Zhongwan(CV 12) for 20 min in the two groups(all P<0. 01). (3) The rise rates of MBPU level about Danzhong(CV 17) and Qihai(CV 6) in the yang-deficiency constitution group were higher than those in the mild constitution group without statistical significance after EA at Zhongwan(CV 12) for 20 min(both P>0. 05). The energy metabolism in CV

  17. Fourier transform infrared spectroscopic study of intact cells of the nitrogen-fixing bacterium Azospirillum brasilense

    NASA Astrophysics Data System (ADS)

    Kamnev, A. A.; Ristić, M.; Antonyuk, L. P.; Chernyshev, A. V.; Ignatov, V. V.

    1997-06-01

    The data of Fourier transform infrared (FTIR) spectroscopic measurements performed on intact cells of the soil nitrogen-fixing bacterium Azospirillum brasilense grown in a standard medium and under the conditions of an increased metal uptake are compared and discussed. The structural FTIR information obtained is considered together with atomic absorption spectrometry (AAS) data on the content of metal cations in the bacterial cells. Some methodological aspects concerning preparation of bacterial cell samples for FTIR measurements are also discussed.

  18. PlantCV v2: Image analysis software for high-throughput plant phenotyping

    PubMed Central

    Abbasi, Arash; Berry, Jeffrey C.; Callen, Steven T.; Chavez, Leonardo; Doust, Andrew N.; Feldman, Max J.; Gilbert, Kerrigan B.; Hodge, John G.; Hoyer, J. Steen; Lin, Andy; Liu, Suxing; Lizárraga, César; Lorence, Argelia; Miller, Michael; Platon, Eric; Tessman, Monica; Sax, Tony

    2017-01-01

    Systems for collecting image data in conjunction with computer vision techniques are a powerful tool for increasing the temporal resolution at which plant phenotypes can be measured non-destructively. Computational tools that are flexible and extendable are needed to address the diversity of plant phenotyping problems. We previously described the Plant Computer Vision (PlantCV) software package, which is an image processing toolkit for plant phenotyping analysis. The goal of the PlantCV project is to develop a set of modular, reusable, and repurposable tools for plant image analysis that are open-source and community-developed. Here we present the details and rationale for major developments in the second major release of PlantCV. In addition to overall improvements in the organization of the PlantCV project, new functionality includes a set of new image processing and normalization tools, support for analyzing images that include multiple plants, leaf segmentation, landmark identification tools for morphometrics, and modules for machine learning. PMID:29209576

  19. PlantCV v2: Image analysis software for high-throughput plant phenotyping.

    PubMed

    Gehan, Malia A; Fahlgren, Noah; Abbasi, Arash; Berry, Jeffrey C; Callen, Steven T; Chavez, Leonardo; Doust, Andrew N; Feldman, Max J; Gilbert, Kerrigan B; Hodge, John G; Hoyer, J Steen; Lin, Andy; Liu, Suxing; Lizárraga, César; Lorence, Argelia; Miller, Michael; Platon, Eric; Tessman, Monica; Sax, Tony

    2017-01-01

    Systems for collecting image data in conjunction with computer vision techniques are a powerful tool for increasing the temporal resolution at which plant phenotypes can be measured non-destructively. Computational tools that are flexible and extendable are needed to address the diversity of plant phenotyping problems. We previously described the Plant Computer Vision (PlantCV) software package, which is an image processing toolkit for plant phenotyping analysis. The goal of the PlantCV project is to develop a set of modular, reusable, and repurposable tools for plant image analysis that are open-source and community-developed. Here we present the details and rationale for major developments in the second major release of PlantCV. In addition to overall improvements in the organization of the PlantCV project, new functionality includes a set of new image processing and normalization tools, support for analyzing images that include multiple plants, leaf segmentation, landmark identification tools for morphometrics, and modules for machine learning.

  20. PlantCV v2: Image analysis software for high-throughput plant phenotyping

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gehan, Malia A.; Fahlgren, Noah; Abbasi, Arash

    Systems for collecting image data in conjunction with computer vision techniques are a powerful tool for increasing the temporal resolution at which plant phenotypes can be measured non-destructively. Computational tools that are flexible and extendable are needed to address the diversity of plant phenotyping problems. We previously described the Plant Computer Vision (PlantCV) software package, which is an image processing toolkit for plant phenotyping analysis. The goal of the PlantCV project is to develop a set of modular, reusable, and repurposable tools for plant image analysis that are open-source and community-developed. Here in this paper we present the details andmore » rationale for major developments in the second major release of PlantCV. In addition to overall improvements in the organization of the PlantCV project, new functionality includes a set of new image processing and normalization tools, support for analyzing images that include multiple plants, leaf segmentation, landmark identification tools for morphometrics, and modules for machine learning.« less

  1. PlantCV v2: Image analysis software for high-throughput plant phenotyping

    DOE PAGES

    Gehan, Malia A.; Fahlgren, Noah; Abbasi, Arash; ...

    2017-12-01

    Systems for collecting image data in conjunction with computer vision techniques are a powerful tool for increasing the temporal resolution at which plant phenotypes can be measured non-destructively. Computational tools that are flexible and extendable are needed to address the diversity of plant phenotyping problems. We previously described the Plant Computer Vision (PlantCV) software package, which is an image processing toolkit for plant phenotyping analysis. The goal of the PlantCV project is to develop a set of modular, reusable, and repurposable tools for plant image analysis that are open-source and community-developed. Here in this paper we present the details andmore » rationale for major developments in the second major release of PlantCV. In addition to overall improvements in the organization of the PlantCV project, new functionality includes a set of new image processing and normalization tools, support for analyzing images that include multiple plants, leaf segmentation, landmark identification tools for morphometrics, and modules for machine learning.« less

  2. Displaying Now-Understanding: The Finnish Change-of-State Token "aa"

    ERIC Educational Resources Information Center

    Koivisto, Aino

    2015-01-01

    This article discusses the use of the Finnish change-of-state token "aa" that has previously not been identified. The central claim is that even though "aa" indicates a cognitive shift experienced by the speaker, it does not function as a receipt of new information. Instead, the token "aa" indicates that the speaker…

  3. A comparison of simultaneous plasma, atomic absorption, and iron colorimetric determinations of major and trace constituents in acid mine waters

    USGS Publications Warehouse

    Ball, J.W.; Nordstrom, D. Kirk

    1994-01-01

    Sixty-three water samples collected during June to October 1982 from the Leviathan/Bryant Creek drainage basin were originally analyzed by simultaneous multielement direct-current plasma (DCP) atomic-emission spectrometry, flame atomic-absorption spectrometry, graphite-furnace atomic-absorption spectrometry (GFAAS) (thallium only), ultraviolet-visible spectrometry, and hydride-generation atomic-absorption spectrometry.Determinations were made for the following metallic and semi-metallic constituents: AI, As, B, Ba, Be, Bi, Cd, Ca, Cr, Co, Cu, Fe(11), Fe(total), Li, Pb, Mg, Mn, Mo, Ni, K, Sb, Se, Si, Na, Sr, TI, V, and Zn. These samples were re-analyzed later by simultaneous multielement inductively coupled plasma (ICP) atomic-emission spectrometry and Zeeman-corrected GFAAS to determine the concentrations of many of the same constituents with improved accuracy, precision, and sensitivity. The result of this analysis has been the generation of comparative concentration values for a significant subset of the solute constituents. Many of the more recently determined values replace less-than-detection values for the trace metals; others constitute duplicate analyses for the major constituents. The multiple determinations have yielded a more complete, accurate, and precise set of analytical data. They also have resulted in an opportunity to compare the performance of the plasma-emission instruments operated in their respective simultaneous multielement modes. Flame atomic-absorption spectrometry was judged best for Na and K and hydride-generation atomic-absorption spectrometry was judged best for As because of their lower detection limit and relative freedom from interelement spectral effects. Colorimetric determination using ferrozine as the color agent was judged most accurate, precise, and sensitive for Fe. Cadmium, lead, and vanadium concentrations were too low in this set of samples to enable a determination of whether ICP or DCP is a more suitable technique. Of

  4. The 9aaTAD Transactivation Domains: From Gal4 to p53.

    PubMed

    Piskacek, Martin; Havelka, Marek; Rezacova, Martina; Knight, Andrea

    2016-01-01

    The family of the Nine amino acid Transactivation Domain, 9aaTAD family, comprises currently over 40 members. The 9aaTAD domains are universally recognized by the transcriptional machinery from yeast to man. We had identified the 9aaTAD domains in the p53, Msn2, Pdr1 and B42 activators by our prediction algorithm. In this study, their competence to activate transcription as small peptides was proven. Not surprisingly, we elicited immense 9aaTAD divergence in hundreds of identified orthologs and numerous examples of the 9aaTAD species' convergence. We found unforeseen similarity of the mammalian p53 with yeast Gal4 9aaTAD domains. Furthermore, we identified artificial 9aaTAD domains generated accidentally by others. From an evolutionary perspective, the observed easiness to generate 9aaTAD transactivation domains indicates the natural advantage for spontaneous generation of transcription factors from DNA binding precursors.

  5. Solution NMR structure of hypothetical protein CV_2116 encoded by a viral prophage element in Chromobacterium violaceum.

    PubMed

    Yang, Yunhuang; Ramelot, Theresa A; Cort, John R; Garcia, Maite; Yee, Adelinda; Arrowsmith, Cheryl H; Kennedy, Michael A

    2012-01-01

    CV_2116 is a small hypothetical protein of 82 amino acids from the Gram-negative coccobacillus Chromobacterium violaceum. A PSI-BLAST search using the CV_2116 sequence as a query identified only one hit (E = 2e(-07)) corresponding to a hypothetical protein OR16_04617 from Cupriavidus basilensis OR16, which failed to provide insight into the function of CV_2116. The CV_2116 gene was cloned into the p15TvLic expression plasmid, transformed into E. coli, and (13)C- and (15)N-labeled NMR samples of CV_2116 were overexpressed in E. coli and purified for structure determination using NMR spectroscopy. The resulting high-quality solution NMR structure of CV_2116 revealed a novel α + β fold containing two anti-parallel β-sheets in the N-terminal two-thirds of the protein and one α-helix in the C-terminal third of the protein. CV_2116 does not belong to any known protein sequence family and a Dali search indicated that no similar structures exist in the protein data bank. Although no function of CV_2116 could be derived from either sequence or structural similarity searches, the neighboring genes of CV_2116 encode various proteins annotated as similar to bacteriophage tail assembly proteins. Interestingly, C. violaceum exhibits an extensive network of bacteriophage tail-like structures that likely result from lateral gene transfer by incorporation of viral DNA into its genome (prophages) due to bacteriophage infection. Indeed, C. violaceum has been shown to contain four prophage elements and CV_2116 resides in the fourth of these elements. Analysis of the putative operon in which CV_2116 resides indicates that CV_2116 might be a component of the bacteriophage tail-like assembly that occurs in C. violaceum.

  6. Dynamic Response and Microstructure Evolution of AA2219-T4 and AA2219-T6 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Olasumboye, A.; Owolabi, G.; Odeshi, A.; Zeytinci, A.; Yilmaz, N.

    2018-02-01

    In this study, the dynamic deformation behavior of AA2219 aluminum alloy was investigated in two different temper conditions: T4 and T6, with a view to determining the effect of heat treatment on the microstructure and flow behavior of the material under high strain rates. Split Hopkinson pressure bar experiment was used in determining the dynamic response of the alloy while a digital image correlation system was employed in visualizing and tracking the surface deformation of the specimens. Optical microscopy and scanning electron microscopy were used to assess the microstructure of the material after following standard metallographic specimen preparation techniques. The results obtained showed heterogeneous deformation of the alloy in the two temper conditions. It was observed that the dynamic mechanical behavior of each sample preparation was dependent on its strength properties due to aging type, which in turn controls the metamorphosis of the strengthening precipitates and the initial microstructure. At the maximum strain rate of 3500 s-1, transformed bands leading to crack nucleation was observed in the AA2219-T4 aluminum alloy while AA2219-T6 had fractured at the same strain rate. The modes of crack formation and growth in the two alloys were found to be similar: nucleation, growth and coalescence of voids. However, shear band bifurcation phenomenon was observed only in the AA2219-T6 alloy.

  7. Dynamic Response and Microstructure Evolution of AA2219-T4 and AA2219-T6 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Olasumboye, A.; Owolabi, G.; Odeshi, A.; Zeytinci, A.; Yilmaz, N.

    2018-06-01

    In this study, the dynamic deformation behavior of AA2219 aluminum alloy was investigated in two different temper conditions: T4 and T6, with a view to determining the effect of heat treatment on the microstructure and flow behavior of the material under high strain rates. Split Hopkinson pressure bar experiment was used in determining the dynamic response of the alloy while a digital image correlation system was employed in visualizing and tracking the surface deformation of the specimens. Optical microscopy and scanning electron microscopy were used to assess the microstructure of the material after following standard metallographic specimen preparation techniques. The results obtained showed heterogeneous deformation of the alloy in the two temper conditions. It was observed that the dynamic mechanical behavior of each sample preparation was dependent on its strength properties due to aging type, which in turn controls the metamorphosis of the strengthening precipitates and the initial microstructure. At the maximum strain rate of 3500 s-1, transformed bands leading to crack nucleation was observed in the AA2219-T4 aluminum alloy while AA2219-T6 had fractured at the same strain rate. The modes of crack formation and growth in the two alloys were found to be similar: nucleation, growth and coalescence of voids. However, shear band bifurcation phenomenon was observed only in the AA2219-T6 alloy.

  8. Aqueous alteration in the Kaba CV3 carbonaceous chondrite

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.; Buseck, Peter R.

    1990-01-01

    Results from TEM and SEM examinations of the Kaba CV3 carbonaceous chondrite are presented, showing that the chondrules and the matrix of Kaba have undergone pervasive low-temperature aqueous alteration, resulting in the formation of Fe-bearing saponite from glass and enstatite in chondrules, and from anhydrous silicates in matrix. The alteration products in Kaba were found to resemble those in other aqueously altered carbonaceous chondrites such as the Mokoia CV3 and in Orgueil CI chondrites and Y-82162 chondrites. However, Kaba lacks the abundant high-Al phyllosilicates, reported for CAIs from Mokoia, and the serpentine and ferrihydrite, found in Orgueil.

  9. Determination of Hg(II) in waters by on-line preconcentration using Cyanex 923 as a sorbent — Cold vapor atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Duan, Taicheng; Song, Xuejie; Xu, Jingwei; Guo, Pengran; Chen, Hangting; Li, Hongfei

    2006-09-01

    Using a solid phase extraction mini-column home-made from a neutral extractant Cyanex 923, inorganic Hg could be on-line preconcentrated and simultaneously separated from methyl mercury. The preconcentrated Hg (II) was then eluted with 10% HNO 3 and subsequently reduced by NaBH 4 to form Hg vapor before determination by cold vapor atomic absorption spectrometry (CVAAS). Optimal conditions for and interferences on the Hg preconcentration and measurement were at 1% HCl, for a 25 mL sample uptake volume and a 10 mL min - 1 sample loading rate. The detection limit was 0.2 ng L - 1 and much lower than that of conventional method (around 15.8 ng L - 1 ). The relative standard deviation (RSD) is 1.8% for measurements of 40 ng L - 1 of Hg and the linear working curve is from 20 to 2000 ng L - 1 (with a correlation coefficient of 0.9996). The method was applied in determination of inorganic Hg in city lake and deep well water (from Changchun, Jilin, China), and recovery test results for both samples were satisfactory.

  10. Direct extraction of lead (II) from untreated human blood serum using restricted access carbon nanotubes and its determination by atomic absorption spectrometry.

    PubMed

    Barbosa, Valéria Maria Pereira; Barbosa, Adriano Francisco; Bettini, Jefferson; Luccas, Pedro Orival; Figueiredo, Eduardo Costa

    2016-01-15

    Oxidized carbon nanotubes were covered with layers of bovine serum albumin to result in so-called restricted-access carbon nanotubes (RACNTs). This material can extract Pb(2+) ions directly from untreated human blood serum while excluding all the serum proteins. The RACNTs have a protein exclusion capacity of almost 100% and a maximum Pb(2+) adsorption capacity of 34.5mg g(-1). High resolution transmission electron microscopy, scanning transmission electron microscopy and energy dispersive spectroscopy were used to confirm the BSA layer and Pb(2+) adsorption sites. A mini-column filled with RACNTs was used in an on-line solid phase extraction system coupled to a thermospray flame furnace atomic absorption spectrometry. At optimized experimental conditions, the method has a detection limit as low as 2.1µg L(-1), an enrichment factor of 5.5, and inter- and intra-day precisions (expressed as relative standard deviation) of <8.1%. Recoveries of the Pb(2+) spiked samples ranged from 89.4% to 107.3% for the extraction from untreated human blood serum. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. A new cloud point extraction procedure for determination of inorganic antimony species in beverages and biological samples by flame atomic absorption spectrometry.

    PubMed

    Altunay, Nail; Gürkan, Ramazan

    2015-05-15

    A new cloud-point extraction (CPE) for the determination of antimony species in biological and beverages samples has been established with flame atomic absorption spectrometry (FAAS). The method is based on the fact that formation of the competitive ion-pairing complex of Sb(III) and Sb(V) with Victoria Pure Blue BO (VPB(+)) at pH 10. The antimony species were individually detected by FAAS. Under the optimized conditions, the calibration range for Sb(V) is 1-250 μg L(-1) with a detection limit of 0.25 μg L(-1) and sensitive enhancement factor of 76.3 while the calibration range for Sb(III) is 10-400 μg L(-1) with a detection limit of 5.15 μg L(-1) and sensitive enhancement factor of 48.3. The precision as a relative standard deviation is in range of 0.24-2.35%. The method was successfully applied to the speciative determination of antimony species in the samples. The validation was verified by analysis of certified reference materials (CRMs). Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Certification of NIST standard reference material 2389a, amino acids in 0.1 mol/L HCl--quantification by ID LC-MS/MS.

    PubMed

    Lowenthal, Mark S; Yen, James; Bunk, David M; Phinney, Karen W

    2010-05-01

    An isotope-dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS) measurement procedure was developed to accurately quantify amino acid concentrations in National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2389a-amino acids in 0.1 mol/L hydrochloric acid. Seventeen amino acids were quantified using selected reaction monitoring on a triple quadrupole mass spectrometer. LC-MS/MS results were compared to gravimetric measurements from the preparation of SRM 2389a-a reference material developed at NIST and intended for use in intra-laboratory calibrations and quality control. Quantitative mass spectrometry results and gravimetric values were statistically combined into NIST-certified mass fraction values with associated uncertainty estimates. Coefficients of variation (CV) for the repeatability of the LC-MS/MS measurements among amino acids ranged from 0.33% to 2.7% with an average CV of 1.2%. Average relative expanded uncertainty of the certified values including Types A and B uncertainties was 3.5%. Mean accuracy of the LC-MS/MS measurements with gravimetric preparation values agreed to within |1.1|% for all amino acids. NIST SRM 2389a will be available for characterization of routine methods for amino acid analysis and serves as a standard for higher-order measurement traceability. This is the first time an ID LC-MS/MS methodology has been applied for quantifying amino acids in a NIST SRM material.

  13. Phytochemical Profiles and Antimicrobial Activities of Allium cepa Red cv. and A. sativum Subjected to Different Drying Methods: A Comparative MS-Based Metabolomics.

    PubMed

    Farag, Mohamed A; Ali, Sara E; Hodaya, Rashad H; El-Seedi, Hesham R; Sultani, Haider N; Laub, Annegret; Eissa, Tarek F; Abou-Zaid, Fouad O F; Wessjohann, Ludger A

    2017-05-08

    Plants of the Allium genus produce sulphur compounds that give them a characteristic (alliaceous) flavour and mediate for their medicinal use. In this study, the chemical composition and antimicrobial properties of Allium cepa red cv. and A. sativum in the context of three different drying processes were assessed using metabolomics. Bulbs were dried using either microwave, air drying, or freeze drying and further subjected to chemical analysis of their composition of volatile and non-volatile metabolites. Volatiles were collected using solid phase micro-extraction (SPME) coupled to gas chromatography-mass spectrometry (GC/MS) with 42 identified volatiles including 30 sulphur compounds, four nitriles, three aromatics, and three esters. Profiling of the polar non-volatile metabolites via ultra-performance liquid chromatography coupled to high resolution MS (UPLC/MS) annotated 51 metabolites including dipeptides, flavonoids, phenolic acids, and fatty acids. Major peaks in GC/MS or UPLC/MS contributing to the discrimination between A. sativum and A. cepa red cv. were assigned to sulphur compounds and flavonoids. Whereas sulphur conjugates amounted to the major forms in A. sativum , flavonoids predominated in the chemical composition of A. cepa red cv. With regard to drying impact on Allium metabolites, notable and clear separations among specimens were revealed using principal component analysis (PCA). The PCA scores plot of the UPLC/MS dataset showed closer metabolite composition of microwave dried specimens to freeze dried ones, and distant from air dried bulbs, observed in both A. cepa and A. sativum . Compared to GC/MS, the UPLC/MS derived PCA model was more consistent and better in assessing the impact of drying on Allium metabolism. A phthalate derivative was found exclusively in a commercial garlic preparation via GC/MS, of yet unknown origin. The freeze dried samples of both Allium species exhibited stronger antimicrobial activities compared to dried specimens

  14. Spontaneous, Experimentally Induced, and Transmissible AA Amyloidosis in Japanese Quail ( Coturnix japonica).

    PubMed

    Nakayama, Yumi; Kamiie, Junichi; Watanabe, Gen; Suzuki, Kazuhiko; Murakami, Tomoaki

    2017-11-01

    The authors describe a spontaneous case of amyloid A (AA) amyloidosis in an adult female Japanese quail ( Coturnix japonica). The bird developed AA amyloidosis secondary to chronic peritonitis caused by a Gram-negative bacillus infection. Mild amyloid deposition was also identified in the intestinal tract of apparently healthy adult individuals, suggesting that quail may develop intestinal amyloidosis with age. Based on these observations, it was hypothesized that quail can develop AA amyloidosis following inflammatory stimulation with lipopolysaccharide (LPS). Therefore, adult quail were repeatedly injected with LPS and the development of AA amyloidosis was confirmed. The amyloid deposition in this model increased when quail amyloid was intravenously injected as an amyloid-enhancing factor. The experiments were repeated with young quail, but amyloid deposits were not observed following LPS injections. However, AA amyloidosis did develop when quail amyloid was injected in addition to LPS. These results indicated that adult quail develop AA amyloidosis after inflammatory stimulation with LPS. Furthermore, quail AA amyloidosis was shown to have transmissibility regardless of age. Interestingly, the authors found that administration of chicken amyloid fibrils also induced AA amyloidosis in young quail. This is the first report of cross-species transmission of avian AA amyloidosis.

  15. Long-term treatment with Nandrolone Decanoate impairs mesenteric vascular relaxation in both sedentary and exercised female rats.

    PubMed

    Caliman, Izabela F; Bernabe, Cristian S; de Melo, Antônio F; Brasil, Girlândia A; do Nascimento, Andrews M; de Lima, Ewelyne M; Figueiredo, Suely G; de Andrade, Tadeu U; Bissoli, Nazaré S

    2017-04-01

    Nandrolone Decanoate (ND) is an Anabolic Androgenic Steroid (AAS) that under abusive regimen can lead to multiple physiological adverse effects. Studies of AAS-mediated cardiovascular (CV) alterations were mostly taken from male subjects, even though women are also susceptible to the effects of AAS and gender-specific differences in susceptibility to vascular diseases exist. Here we investigate ND-induced vascular reactivity alterations in both sedentary and exercised female rats and whether these alterations depend on endothelium-derived factors. We show that chronic exposure of female Wistar rats to ND (20mg/Kg/week for 4weeks) impaired the vascular mesenteric bed (MVB) reactivity to vasodilator (acetylcholine) agonist. The endothelium-dependent Nitric Oxide (NO) component was reduced in ND-treated rats, whereas neither the endothelium-derived hyperpolarizing factor (EDHF) component nor prostanoids were altered in the MVBs. Endothelial dysfunction observed in ND-treated rats was associated with decreased eNOS (Ser 1177 ) and Akt (Ser 473 ) phosphorylation sites and upregulation of iNOS and NADPH oxidase expression. Exercise training by weight lifting in water did not improve the vascular alterations induced by ND treatment. ND treatment also significantly reduced the serum levels of estradiol in females, overriding its CV protective effect. These results help uncover the role of ND modulating endothelial function in the setting of CV disease caused by the abuse of AAS in females. If this translates to humans, young women abusing AAS can potentially lose the cardio protective effect rendered by estrogen and be more susceptible to CV alterations. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Determination of elements in ayurvedic medicinal plants by AAS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Teerthe, Santoshkumar S.; Kerur, B. R., E-mail: kerurbrk@yahoo.com

    India has a rich country for the uses of Ayurvedic medicinal plants for treatment and also the north- Karnataka boasts an unparallel diversity of medicinal plants. The present study attempts to estimate and compare the level of trace and heavy metals in some selected leaves and root samples of Ayurvedic medicinal plants such as Mg, Al, K, Cr, Mn, Fe, Cu, Zn, and Cd. The samples are collected from different places of North-Karnataka regions and sample solutions prepared as the ratio of 1:25:25+950ml=1000ppm.the trace and heavy elemental concentration was estimated using Atomic Absorption Spectrometric (AAS) Method. The average concentrations ofmore » Mg, Mn, Fe and Zn, are ranging from 2ppm to 5250.2ppm and potassium (K) has more concentration as compare to all other. The other elements likes Al, Cr, Cu, and Cd were also estimed and presented in the table. Therefore, these medicinal plants are rich in some essential minerals, especially K, Mg, Mn, Fe and Zn which are essential for human health.« less

  17. Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo

    PubMed Central

    Xiao, Qi; Zhou, Yachun; Wei, Yingjie; Gong, Zhunan

    2018-01-01

    Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear. Methods In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined. Results We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling

  18. Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo.

    PubMed

    Jing, Yue; Wang, Gang; Xiao, Qi; Zhou, Yachun; Wei, Yingjie; Gong, Zhunan

    2018-01-01

    Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear. In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined. We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling. For the first time

  19. Biomonitoring of Aristolactam-DNA Adducts in Human Tissues using Ultra-Performance Liquid Chromatography/Ion-Trap Mass Spectrometry

    PubMed Central

    Yun, Byeong Hwa; Rosenquist, Thomas; Sidorenko, Viktoriya; Iden, Charles; Chung-Hsin, Chen; Pu, Yeong-Shiau; Bonala, Radha; Johnson, Francis; Dickman, Kathleen G.; Grollman, Arthur P.; Turesky, Robert J.

    2012-01-01

    Aristolochic acids (AAs) are a structurally-related family of nephrotoxic and carcinogenic nitrophenanthrene compounds found in Aristolochia herbaceous plants, many of which have been used worldwide for medicinal purposes. AAs have been implicated in the etiology of so-called Chinese herbs nephropathy and of Balkan endemic nephropathy. Both of these disease syndromes are associated with carcinomas of the upper urinary tract (UUC). 8-Methoxy-6-nitrophenanthro-[3,4-d]-1,3-dioxolo-5-carboxylic acid (AA-I) is a principal component of Aristolochia herbs. Following metabolic activation, AA-I reacts with DNA to form aristolactam (AL-I)-DNA adducts. We have developed a sensitive analytical method, using ultra-performance liquid chromatography-electrospray ionization/multistage mass spectrometry (UPLC-ESI/MSn) with a linear quadrupole ion-trap mass spectrometer, to measure 7-(deoxyadenosin-N6-yl) aristolactam I (dA-AL-I) and 7-(deoxyguanosin-N2-yl) aristolactam I (dG-AL-I) adducts. Using 10 μg of DNA for measurements, the lower limits of quantitation of dA-AL-I and dG-AL-I are, respectively, 0.3 and 1.0 adducts per 108 DNA bases. We have used UPLC-ESI/MSn to quantify AL-DNA adducts in tissues of rodents exposed to AA, and in the renal cortex of patients with UUC who reside in Taiwan, where the incidence of this uncommon cancer is the highest reported for any country in the world. In human tissues, dA-AL-I was detected at levels ranging from 9 to 338 adducts per 108 DNA bases, whereas dG-AL-I was not found. We conclude that UPLC-ESI/MSn is a highly sensitive, specific and robust analytical method, positioned to supplant 32P-postlabeling techniques currently used for biomonitoring of DNA adducts in human tissues. Importantly, UPLC-ESI/MSn could be used to document exposure to AA, the toxicant responsible for AA nephropathy and its associated UUC. PMID:22515372

  20. A flow-batch analyzer with piston propulsion applied to automatic preparation of calibration solutions for Mn determination in mineral waters by ET AAS.

    PubMed

    Almeida, Luciano F; Vale, Maria G R; Dessuy, Morgana B; Silva, Márcia M; Lima, Renato S; Santos, Vagner B; Diniz, Paulo H D; Araújo, Mário C U

    2007-10-31

    The increasing development of miniaturized flow systems and the continuous monitoring of chemical processes require dramatically simplified and cheap flow schemes and instrumentation with large potential for miniaturization and consequent portability. For these purposes, the development of systems based on flow and batch technologies may be a good alternative. Flow-batch analyzers (FBA) have been successfully applied to implement analytical procedures, such as: titrations, sample pre-treatment, analyte addition and screening analysis. In spite of its favourable characteristics, the previously proposed FBA uses peristaltic pumps to propel the fluids and this kind of propulsion presents high cost and large dimension, making unfeasible its miniaturization and portability. To overcome these drawbacks, a low cost, robust, compact and non-propelled by peristaltic pump FBA is proposed. It makes use of a lab-made piston coupled to a mixing chamber and a step motor controlled by a microcomputer. The piston-propelled FBA (PFBA) was applied for automatic preparation of calibration solutions for manganese determination in mineral waters by electrothermal atomic-absorption spectrometry (ET AAS). Comparing the results obtained with two sets of calibration curves (five by manual and five by PFBA preparations), no significant statistical differences at a 95% confidence level were observed by applying the paired t-test. The standard deviation of manual and PFBA procedures were always smaller than 0.2 and 0.1mugL(-1), respectively. By using PFBA it was possible to prepare about 80 calibration solutions per hour.

  1. Reclassification of Hart and Northwest Africa 6047: Criteria for distinguishing between CV and CK3 chondrites

    NASA Astrophysics Data System (ADS)

    Dunn, Tasha L.; Gross, Juliane

    2017-11-01

    The single parent body model for the CV and CK chondrites (Greenwood et al.) was challenged by Dunn et al., who argued that magnetite compositions could not be reconciled by a single metamorphic sequence (i.e., CV3 → CK3 → CK4-6). Cr isotopic compositions, which are distinguishable between the CV and CK chondrites, also support two different parent bodies (Yin et al.). Despite this, there are many petrographic and mineralogical similarities between the unequilibrated (petrologic type 3) CK chondrites and the CV chondrites (also type 3), which may result in misclassification of samples. Hart and Northwest Africa 6047 (NWA 6047) are an excellent example of this. In this study, we revisit the classification of Hart and NWA 6047 using magnetite compositions, petrography, and compositions of olivine, the most ubiquitous mineral in both CV and CK chondrites. Not only do our results suggest that NWA 6047 and Hart were misclassified, but our assessment of CV and CK3 chondrites has also led to the development of criteria that can be used to distinguish between CV and CK3 chondrites. These criteria include: abundances of Cr2O3, TiO2, NiO, and Al2O3 in magnetite; Fa content and NiO abundance of matrix olivine; FeO content of chondrules; and the chondrule:matrix ratio. Classification as a CV chondrite is also supported by the presence of igneous chondrule rims, calcium-aluminum-rich inclusions, and an elongated petrofabric. However, none of these petrographic characteristics can be used conclusively to distinguish between CV and CK3 chondrites.

  2. Controlled release of bioactive PDGF-AA from a hydrogel/nanoparticle composite.

    PubMed

    Elliott Donaghue, Irja; Shoichet, Molly S

    2015-10-01

    Polymer excipients, such as low molar mass poly(ethylene glycol) (PEG), have shown contradictory effects on protein stability when co-encapsulated in polymeric nanoparticles. To gain further insight into these effects, platelet-derived growth factor (PDGF-AA) was encapsulated in polymeric nanoparticles with vs. without PEG. PDGF-AA is a particularly compelling protein, as it has been demonstrated to promote cell survival and induce the oligodendrocyte differentiation of neural stem/progenitor cells (NSPCs) both in vitro and in vivo. Here we show, for the first time, the controlled release of bioactive PDGF-AA from an injectable nanoparticle/hydrogel drug delivery system (DDS). PDGF-AA was encapsulated, with high efficiency, in poly(lactide-co-glycolide) nanoparticles, and its release from the drug delivery system was followed over 21 d. Interestingly, the co-encapsulation of low molecular weight poly(ethylene glycol) increased the PDGF-AA loading but, unexpectedly, accelerated the aggregation of PDGF-AA, resulting in reduced activity and detection by enzyme-linked immunosorbent assay (ELISA). In the absence of PEG, released PDGF-AA remained bioactive as demonstrated with NSPC oligodendrocyte differentiation, similar to positive controls, and significantly different from untreated controls. This work presents a novel delivery method for differentiation factors, such as PDGF-AA, and provides insights into the contradictory effects reported in the literature of excipients, such as PEG, on the loading and release of proteins from polymeric nanoparticles. Previously, the polymer poly(ethylene glycol) (PEG) has been used in many biomaterials applications, from surface coatings to the encapsulation of proteins. In this work, we demonstrate that, unexpectedly, low molecular weight PEG has a deleterious effect on the release of the encapsulated protein platelet-derived growth factor AA (PDGF-AA). We also demonstrate release of bioactive PDGF-AA (in the absence of PEG

  3. Impurity profiling of liothyronine sodium by means of reversed phase HPLC, high resolution mass spectrometry, on-line H/D exchange and UV/Vis absorption.

    PubMed

    Ruggenthaler, M; Grass, J; Schuh, W; Huber, C G; Reischl, R J

    2017-09-05

    For the first time, a comprehensive investigation of the impurity profile of the synthetic thyroid API (active pharmaceutical ingredient) liothyronine sodium (LT 3 Na) was performed by using reversed phase HPLC and advanced structural elucidation techniques including high resolution tandem mass spectrometry (HRMS/MS) and on-line hydrogen-deuterium (H/D) exchange. Overall, 39 compounds were characterized and 25 of these related substances were previously unknown to literature. The impurity classification system recently developed for the closely related API levothyroxine sodium (LT 4 Na) could be applied to the newly characterized liothyronine sodium impurities resulting in a wholistic thyroid API impurity classification system. Furthermore, the mass-spectrometric CID-fragmentation of specific related substances was discussed and rationalized by detailed fragmentation pathways. Moreover, the UV/Vis absorption characteristics of the API and selected impurities were investigated to corroborate chemical structure assignments derived from MS data. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. An automated flow injection system for metal determination by flame atomic absorption spectrometry involving on-line fabric disk sorptive extraction technique.

    PubMed

    Anthemidis, A; Kazantzi, V; Samanidou, V; Kabir, A; Furton, K G

    2016-08-15

    A novel flow injection-fabric disk sorptive extraction (FI-FDSE) system was developed for automated determination of trace metals. The platform was based on a minicolumn packed with sol-gel coated fabric media in the form of disks, incorporated into an on-line solid-phase extraction system, coupled with flame atomic absorption spectrometry (FAAS). This configuration provides minor backpressure, resulting in high loading flow rates and shorter analytical cycles. The potentials of this technique were demonstrated for trace lead and cadmium determination in environmental water samples. The applicability of different sol-gel coated FPSE media was investigated. The on-line formed complex of metal with ammonium pyrrolidine dithiocarbamate (APDC) was retained onto the fabric surface and methyl isobutyl ketone (MIBK) was used to elute the analytes prior to atomization. For 90s preconcentration time, enrichment factors of 140 and 38 and detection limits (3σ) of 1.8 and 0.4μgL(-1) were achieved for lead and cadmium determination, respectively, with a sampling frequency of 30h(-1). The accuracy of the proposed method was estimated by analyzing standard reference materials and spiked water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Comparison of ``AA`` nickel metal hydride cells with ``AA`` Ni-Cd cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alminauskas, V.; Johnson, W.

    1996-12-31

    This paper compares ``AA`` size nickel metal hydride (Ni-HM) cells with comparable ``AA;; nickel cadmium (Ni-Cd) cells both of which were obtained in 1993. The Ni-MH cells were found to be a suitable substitute for conventional Ni-Cd cells. Both these cell types have similar voltages and discharge characteristics. The Ni-MH cells, though had nearly twice the capacity as comparable Ni-Cd cells. There was no significant difference in self discharge between the two types of cells. The Ni-MH cells also performed as well as Ni-Cd cells at rates lower than 5 amperes and at temperatures higher than 0 C (32 F).more » The most interesting finding is that the Ni-MH cells showed an irreversible decay of the discharge voltage with each cycle which was more noticeable during pulses. Eventually the Ni-MH packs fail, not because of loss of capacity, but because of low voltage during the pulse.« less

  6. The influence of alkalinity of portland cement on the absorption characteristics of superabsorbent polymers (SAP) for use in internally cured concrete

    NASA Astrophysics Data System (ADS)

    Tabares Tamayo, Juan D.

    The concrete industry increasingly emphasizes advances in novel materials that promote construction of more resilient infrastructure. Due to its potential to improve concrete durability, internal curing (IC) of concrete by means of superabsorbent polymers (SAP) has been identified as one of the most promising technologies of the 21st century. The addition of superabsorbent polymers into a cementitious system promotes further hydration of cement by providing internal moisture during the hardening and strength development periods, and thus limits self-desiccation, shrinkage, and cracking. This thesis presents the work performed on the series of cement pastes with varying alkalinity of their pore solutions to provide a better understanding of: (1) the influence of the chemistry of the pore solution (i.e. its level of alkalinity and the type of ionic species present) on the absorption capacity of SAP, and (2) the effectiveness of SAP with different absorption capacities as an internal curing agent. This research work was divided into three stages: (a) materials characterization, (b) measurement of absorption capacity of SAP in synthetic pore solutions, and (c) evaluation of the internal curing effectiveness of SAP. During the first stage (Materials Characterization), pore solutions were extracted from the fresh (5 minutes old) cement pastes prepared using cements with three different levels of alkalinity. The pH values of the extracted solutions were determined (using the pH meter) and their chemical analysis was performed by means of titration (concentration of hydroxyl), ion chromatography (sulfates and chlorides), atomic absorption (AA) and inductively coupled plasma optical emission spectrometry (ICP) (sodium, potassium and calcium). The commercial SAP adopted for this study was used with "as-supplied" gradation and with the finer gradation obtained by grinding the original polymer in the 6850 Cryomilling Freezer/Mill. The physical properties of these SAP's, such

  7. Inhibitory effect of propolis on the development of AA amyloidosis.

    PubMed

    Harata, Daichi; Tsuchiya, Yuya; Miyoshi, Tomoyuki; Yanai, Tokuma; Suzuki, Kazuhiko; Murakami, Tomoaki

    2018-04-01

    In the several types of amyloidoses, participation of oxidative stresses in the pathogenesis and the effect of antioxidants on amyloidosis have been reported. Meanwhile, the relationship between oxidative stresses and pathogenesis of amyloid A (AA) amyloidosis is still unclear. In this study, we used an antioxidant, Brazilian propolis, to investigate the inhibitory effects on AA amyloidosis. The results showed that AA deposition was inhibited by administration of propolis. Increased expression of antioxidant markers was detected in molecular biological examinations of mice treated with propolis. Although serum amyloid A (SAA) levels were strongly correlated with the immunoreactive area of AA deposits in the control group, the correlation was weaker in the propolis-treated groups. In addition, there were no changes in SAA levels between the control group and the propolis-treated groups. The results indicate that propolis, an antioxidant, may induce inhibitory effects against AA amyloidosis.

  8. Concurrent Label-Free Mass Spectrometric Analysis of Dystrophin Isoform Dp427 and the Myofibrosis Marker Collagen in Crude Extracts from mdx-4cv Skeletal Muscles

    PubMed Central

    Murphy, Sandra; Zweyer, Margit; Mundegar, Rustam R.; Henry, Michael; Meleady, Paula; Swandulla, Dieter; Ohlendieck, Kay

    2015-01-01

    The full-length dystrophin protein isoform of 427 kDa (Dp427), the absence of which represents the principal abnormality in X-linked muscular dystrophy, is difficult to identify and characterize by routine proteomic screening approaches of crude tissue extracts. This is probably related to its large molecular size, its close association with the sarcolemmal membrane, and its existence within a heterogeneous glycoprotein complex. Here, we used a careful extraction procedure to isolate the total protein repertoire from normal versus dystrophic mdx-4cv skeletal muscles, in conjunction with label-free mass spectrometry, and successfully identified Dp427 by proteomic means. In contrast to a considerable number of previous comparative studies of the total skeletal muscle proteome, using whole tissue proteomics we show here for the first time that the reduced expression of this membrane cytoskeletal protein is the most significant alteration in dystrophinopathy. This agrees with the pathobiochemical concept that the almost complete absence of dystrophin is the main defect in Duchenne muscular dystrophy and that the mdx-4cv mouse model of dystrophinopathy exhibits only very few revertant fibers. Significant increases in collagens and associated fibrotic marker proteins, such as fibronectin, biglycan, asporin, decorin, prolargin, mimecan, and lumican were identified in dystrophin-deficient muscles. The up-regulation of collagen in mdx-4cv muscles was confirmed by immunofluorescence microscopy and immunoblotting. Thus, this is the first mass spectrometric study of crude tissue extracts that puts the proteomic identification of dystrophin in its proper pathophysiological context. PMID:28248273

  9. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR EXTRACTION OF METALS FROM SOIL, DUST, AIR FILTER, AND SURFACE AND DERMAL SAMPLES FOR AA (GRAPHITE FURNACE OR FLAME) OR ICP-AES ANALYSIS (BCO-L-3.1)

    EPA Science Inventory

    The purpose of this SOP is to describe the acid digestion of soil, house dust, air filter, and surface or dermal wipe samples for analysis using inductively coupled plasma atomic emissions spectrometry (ICP-AES) and/or graphite furnace atomic absorption spectrometry (GFAAS) or fl...

  10. Determination of mercury in agroindustrial samples by flow-injection cold vapor atomic absorption spectrometry using ion exchange and reductive elution.

    PubMed

    Gomes Neto, J A; Zara, L F; Rocha, J C; Santos, A; Dakuzaku, C S; Nóbrega, J A

    2000-03-06

    A flow-injection system with a Chelite-S(R) cationic resin packed minicolumn is proposed for the determination of trace levels of mercury in agroindustrial samples by cold vapor atomic absorption spectrometry. Improved sensitivity and selectivity are attained since mercuric ions are on-line concentrated whereas other potential interferents are discarded. With on-line reductive elution procedure, concentrated hydrochloric acid could be replaced by 10% w/v SnCl(2), in 6 M HCl as eluent. The reversed-intermittent stream either carries the atomic mercury to the flow cell in the forward direction or removes the residue from reactor/gas-liquid separator to a discarding flask in the opposite direction. Concentration and volume of reagent, acidity, flow rates, commutation times and potential interfering species were investigated. For 120 s preconcentration time, the proposed system handles about 25 samples h(-1) (50.0-500 ng l(-1)), consuming about 10 ml sample and 5 mg SnCl(2) per determination. The detection limit is 0.8 ng l(-1) and the relative standard deviation (RSD) (n=12) of a 76.7 ng l(-1) sample is about 5%. Results are in agreement with certified value of standard materials at 95% confidence level and good recoveries (97-128%) of spiked samples were found.

  11. Standardization and validation of a new atomic absorption spectroscopy technique for determination and quantitation of aluminium adjuvant in immunobiologicals.

    PubMed

    Mishra, Arti; Bhalla, Sumir Rai; Rawat, Sameera; Bansal, Vivek; Sehgal, Rakesh; Kumar, Sunil

    2007-10-01

    In the present study, Aluminium quantification in immunobiologicals has been described using atomic absorption spectroscopy (AAS) technique. The assay was found to be linear in 25-125 microg/ml Aluminium range. The procedure was found to be accurate for different vaccines with recoveries of external additions ranging between 93.26 and 103.41%. The mean Limit of Variation (L.V.) for both intra- and inter-assay precision was calculated to be 1.62 and 2.22%, respectively. Further the procedure was found to be robust in relation to digestion temperature, alteration in acid (HNO(3) and H(2)SO(4)) ratio used for sample digestion and storage of digested vaccine samples up to a period of 15 days. After validation, AAS method was compared for its equivalency with routinely used complexometric titration method. On simultaneously applying on seven different groups of both bacterial and viral vaccines, viz., DPT, DT, TT, Hepatitis-A and B, Antirabies vaccine (cell culture) and tetravalent DPT-Hib, a high degree of positive correlation (+0.85-0.998) among AAS and titration methods was observed. Further AAS method was found to have an edge over complexometric titration method that a group of vaccines, viz., ARV (cell culture, adsorbed) and Hepatitis-A, in which Aluminium estimation is not feasible by pharmacopoeial approved complexometric titration method (possibly due to some interference in the sample matrix), this newly described and validated AAS assay procedure delivered accurate and reproducible results.

  12. Aqueous Alteration of the Grosnaja CV3 Carbonaceous Chondrite

    NASA Astrophysics Data System (ADS)

    Keller, L. P.; McKay, D. S.

    1993-07-01

    Previous petrographic studies have shown that aqueous alteration products are locally well developed in some of the CV3 falls [e.g., 1-3]. In this abstract, we describe our transmission electron microscope (TEM) study of the extent of aqueous alteration in matrix and in chondrules in the Grosnaja CV3 carbonaceous chondrite. Grosnaja is an observed fall and belongs to the oxidized subgroup of the CV chondrites [4]. We obtained fragments of Grosnaja from the Naturhistorisches Museum in Vienna. Regions of interest were extracted from polished thin sections and prepared for TEM observation by ion milling. Quantitative energy-dispersive X-ray (EDX) analyses were obtained using a JEOL 2000FX TEM equipped with a LINK thin- window EDX detector. Grosnaja has undergone aqueous alteration, which has resulted in the formation of phyllosilicates in matrix and in chondrules. The suprising result from Grosnaja is that three different types of phyllosilicates are intimately intergrown. Serpentine is the most abundant phyllosilicate in matrix and occurs as fine-grained packets along grain boundaries and as fracture-fillings and veinlets that cross cut olivine and pyroxene grains. Mixed with the serpentine are packets of fine-grained phyllosilicates with a distinct 1.4-nm basal spacing that is probably a chlorite group mineral. Rare packets of smectite occur as epitaxial intergrowths with olivine, but are not interstratified with serpentine as observed in the CI chondrites. Phyllosilicates in Grosnaja matrix occur with Mg-rich carbonates, fine-grained magnetite, chromite and pentlandite, and poorly-crystalline FeNi- oxide/hydroxides, which stain the matrix a brownish-red color. Some of the rust may be of terrestrial origin (Grosnaja fell in 1861). Although the matrix phyllosilicates are too small to obtain single-phase chemical analyses in the TEM, quantitative EDX analyses suggest that the serpentine contains significant Fe (Mg/Mg + Fe ~0.5). The serpentine/chlorite forms as an

  13. Introducing the AAS Astronomy Ambassadors Program

    NASA Astrophysics Data System (ADS)

    Gurton, S.; Fienberg, R. T.; Fraknoi, A.; Prather, E. E.

    2013-04-01

    Newly established by the American Astronomical Society (AAS), the Astronomy Ambassadors program is designed to support early-career AAS members with training in resources and techniques for effective outreach to students and/or the public. A pilot Astronomy Ambassadors workshop will be held at the January 2013 AAS meeting. Workshop participants will learn to communicate effectively with public and school audiences; find outreach opportunities and establish ongoing partnerships with local schools, science centers, museums, parks, and/or community centers; reach audiences with personal stories, hands-on activities, and jargon-free language; identify strategies and techniques to improve their presentation skills; gain access to a menu of outreach resources that work in a variety of settings; and become part of an active community of astronomers who do outreach. Applications are welcome from advanced undergraduates (those doing research and committed to continuing in astronomy), graduate students, and postdocs and new faculty in their first two years after receipt of the PhD. We especially encourage applications from members of groups that are presently underrepresented in science.

  14. Analysis of aldehydes in beer by gas-diffusion microextraction: characterization by high-performance liquid chromatography-diode-array detection-atmospheric pressure chemical ionization-mass spectrometry.

    PubMed

    Gonçalves, Luís Moreira; Magalhães, Paulo Jorge; Valente, Inês Maria; Pacheco, João Grosso; Dostálek, Pavel; Sýkora, David; Rodrigues, José António; Barros, Aquiles Araújo

    2010-06-11

    In this work, a recently developed extraction technique for sample preparation aiming the analysis of volatile and semi-volatile compounds named gas-diffusion microextraction (GDME) is applied in the chromatographic analysis of aldehydes in beer. Aldehydes-namely acetaldehyde (AA), methylpropanal (MA) and furfural (FA)-were simultaneously extracted and derivatized with 2,4-dinitrophenylhydrazine (DNPH), then the derivatives were separated and analyzed by high-performance liquid chromatography with spectrophotometric detection (HPLC-UV). The identity of the eluted compounds was confirmed by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass-spectrometry detection in the negative ion mode (HPLC-APCI-MS). The developed methodology showed good repeatability (ca. 5%) and linearity as well as good limits of detection (AA-12.3, FA-1.5 and MA 5.4microgL(-1)) and quantification (AA-41, FA-4.9 and MA 18microgL(-1)); it also appears to be competitive in terms of speed and cost of analysis. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Outcomes From AAS Hack Day at the 227th AAS Meeting

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This is a final post from the 227th AAS Meeting in Kissimmee, FL. This special summary of AAS Hack Day, a meeting of AAS members to collaboratively work on various small projects, was written by Meredith Rawls (@Merrdiff) and was originally posted on astrobites.com.As the 227thAmerican Astronomical Society meeting drew to a close (see highlights from Day 1, Day 2, Day 3, and Day 4), a group of at least 50 attendees spent Day 4working on small projects fondly called hacks. Thanks to sponsorship from LSST and Northrup Grumman, the industrious hackers werewell-caffeinated and fed so we could devote time and energy toworking in groups on one-day projects.TheHack Day beganat 10am with pitches. Anybody with a project idea was welcome to briefly speak and try to convince others to work with them. Only someideas panned out, but the enthusiasm was palpable. Its not every day you get a full room of astronomers and affiliates eager to spend hours working on fun and useful projects to benefit the community.#hackAAS is getting underway! #aas227 pic.twitter.com/yX7jlOnSCK James R A Davenport (@jradavenport) January 8, 2016Here is a rundown of what we accomplished. Pretty impressive for a single day! Many thanks to fellow astrobiter Erika Nesvold (now at Carnegie DTM; @erikanesvold) whose hack was live-documenting all the other hacks. Her tweets as @astrobites appeared with the #hackaas hashtag, and her notes made this recap post infinitely easier to write.Interested in joining the fun? Sign up for Hack Day at the 2017 JanuaryAAS meeting (its free with meeting registration), and consider applying for the .Astronomy conference this summer.Towards Optimal Session Scheduling:Adrian Price-Whelan (Columbia), David Hogg (NYU), and Scott Idem (AAS) began writing a program to take all submitted abstracts to a conference like AAS and sort them using keywords to avoid scheduling similar talks in parallel sessions. Its impossible to make everyone happy, but minimizing conflicts

  16. DEVELOPMENTAL AND WITHDRAWAL EFFECTS OF ADOLESCENT AAS EXPOSURE ON THE GLUTAMATERGIC SYSTEM IN HAMSTERS

    PubMed Central

    Carrillo, Maria; Ricci, Lesley A.; Melloni, Richard H.

    2011-01-01

    In the Syrian hamster (Mesocricetus auratus) glutamate activity has been implicated in the modulation of adolescent anabolic-androgenic steroid (AAS)-induced aggression. The current study investigated the time course of adolescent AAS-induced neurodevelopmental and withdrawal effects on the glutamatergic system and examined whether these changes paralleled those of adolescent AAS-induced aggression. Glutamate activity in brain areas comprising the aggression circuit in hamsters and aggression were examined following 1, 2, 3 and 4 weeks of AAS treatment or 1, 2, 3 and 4 weeks following the cessation of AAS exposure. In these studies glutamate activity was examined using vesicular glutamate transporter 2 (VGLUT2). The onset of aggression was observed following 2 weeks exposure to AAS and continued to increase showing maximal aggression levels after 4 weeks of AAS treatment. This aggressive phenotype was detected after 2 weeks of withdrawal from AAS. The time-course of AAS-induced changes in latero anterior hypothalamus (LAH)-VGLUT2 closely paralleled increases in aggression. Increases in LAH-VGLUT2 were first detected in animals exposed to AAS for 2 weeks and were maintained up to 3 weeks following the cessation of AAS treatment. AAS treatment also produced developmental and long-term alterations in VGLUT2 expression within other aggression areas. However, AAS-induced changes in glutamate activity within these regions did not coincide with changes in aggression. Together, these data indicate that adolescent AAS treatment leads to alterations in the glutamatergic system in brain areas implicated in aggression control, yet only alterations in LAH-glutamate parallel the time course of AAS-induced changes in the aggressive phenotype. PMID:21500881

  17. Remote laser evaporative molecular absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Hughes, Gary B.; Lubin, Philip; Cohen, Alexander; Madajian, Jonathan; Kulkarni, Neeraj; Zhang, Qicheng; Griswold, Janelle; Brashears, Travis

    2016-09-01

    We describe a novel method for probing bulk molecular and atomic composition of solid targets from a distant vantage. A laser is used to melt and vaporize a spot on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption occurs as the blackbody radiation passes through the ejected plume. Bulk molecular and atomic composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected plume. The proposed method is distinct from current stand-off approaches to composition analysis, such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes target material and observes emission spectra to determine bulk atomic composition. Initial simulations of absorption profiles with laser heating show great promise for Remote Laser-Evaporative Molecular Absorption (R-LEMA) spectroscopy. The method is well-suited for exploration of cold solar system targets—asteroids, comets, planets, moons—such as from a spacecraft orbiting the target. Spatial composition maps could be created by scanning the surface. Applying the beam to a single spot continuously produces a borehole or trench, and shallow subsurface composition profiling is possible. This paper describes system concepts for implementing the proposed method to probe the bulk molecular composition of an asteroid from an orbiting spacecraft, including laser array, photovoltaic power, heating and ablation, plume characteristics, absorption, spectrometry and data management.

  18. Ionic liquid-based extraction followed by graphite-furnace atomic absorption spectrometry for the determination of trace heavy metals in high-purity iron metal.

    PubMed

    Matsumiya, Hiroaki; Kato, Tatsuya; Hiraide, Masataka

    2014-02-01

    The analysis of high-purity materials for trace impurities is an important and challenging task. The present paper describes a facile and sensitive method for the determination of trace heavy metals in high-purity iron metal. Trace heavy metals in an iron sample solution were rapidly and selectively preconcentrated by the extraction into a tiny volume of an ionic liquid [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide] for the determination by graphite-furnace atomic absorption spectrometry (GFAAS). A nitrogen-donating neutral ligand, 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ), was found to be effective in the ionic liquid-based selective extraction, allowing the nearly complete (~99.8%) elimination of the iron matrix. The combination with the optimized GFAAS was successful. The detectability reached sub-μg g(-1) levels in iron metal. The novel use of TPTZ in ionic liquid-based extraction followed by GFAAS was successfully applied to the determination of traces of Co, Ni, Cu, Cd, and Pb in certified reference materials for high-purity iron metal. © 2013 Published by Elsevier B.V.

  19. Vortex-assisted switchable liquid-liquid microextraction for the preconcentration of cadmium in environmental samples prior to its determination with flame atomic absorption spectrometry.

    PubMed

    Fırat, Merve; Bodur, Süleyman; Tışlı, Büşra; Özlü, Cansu; Chormey, Dotse Selali; Turak, Fatma; Bakırdere, Sezgin

    2018-06-12

    In this study, a switchable solvent was used to preconcentrate trace amounts of Cd from aqueous solution for its determination by flame atomic absorption spectrometry (FAAS). Protonation of N,N-dimethylbenzylamine by dry ice (solid CO 2 ) made it water soluble, and addition of sodium hydroxide converted it back to its original nonionic state for phase separation and subsequent extraction of Cd. A slotted quartz tube (SQT) was attached to the flame burner head to increase the residence time of Cd atoms in the light path. Under the optimum conditions, limits of detection and quantification were determined as 0.7 and 2.6 μg L -1 , respectively. Low relative standard deviations calculated from seven replicate measurements of the lowest concentration indicated high precision. Accuracy of the developed method was checked by using a standard reference material (SRM 1633c). Spiked recovery tests were also performed on lake water and wastewater samples at different concentrations to check the applicability of the developed method, and the results obtained (90-103%) established high recovery.

  20. Quantitative twoplex glycan analysis using 12C6 and 13C6 stable isotope 2-aminobenzoic acid labelling and capillary electrophoresis mass spectrometry.

    PubMed

    Váradi, Csaba; Mittermayr, Stefan; Millán-Martín, Silvia; Bones, Jonathan

    2016-12-01

    Capillary electrophoresis (CE) offers excellent efficiency and orthogonality to liquid chromatographic (LC) separations for oligosaccharide structural analysis. Combination of CE with high resolution mass spectrometry (MS) for glycan analysis remains a challenging task due to the MS incompatibility of background electrolyte buffers and additives commonly used in offline CE separations. Here, a novel method is presented for the analysis of 2-aminobenzoic acid (2-AA) labelled glycans by capillary electrophoresis coupled to mass spectrometry (CE-MS). To ensure maximum resolution and excellent precision without the requirement for excessive analysis times, CE separation conditions including the concentration and pH of the background electrolyte, the effect of applied pressure on the capillary inlet and the capillary length were evaluated. Using readily available 12/13 C 6 stable isotopologues of 2-AA, the developed method can be applied for quantitative glycan profiling in a twoplex manner based on the generation of extracted ion electropherograms (EIE) for 12 C 6 'light' and 13 C 6 'heavy' 2-AA labelled glycan isotope clusters. The twoplex quantitative CE-MS glycan analysis platform is ideally suited for comparability assessment of biopharmaceuticals, such as monoclonal antibodies, for differential glycomic analysis of clinical material for potential biomarker discovery or for quantitative microheterogeneity analysis of different glycosylation sites within a glycoprotein. Additionally, due to the low injection volume requirements of CE, subsequent LC-MS analysis of the same sample can be performed facilitating the use of orthogonal separation techniques for structural elucidation or verification of quantitative performance.

  1. Measurements of atmospheric ethene by solar absorption FTIR spectrometry

    NASA Astrophysics Data System (ADS)

    Toon, Geoffrey C.; Blavier, Jean-Francois L.; Sung, Keeyoon

    2018-04-01

    Atmospheric ethene (C2H4; ethylene) amounts have been retrieved from high-resolution solar absorption spectra measured by the Jet Propulsion Laboratory (JPL) MkIV interferometer. Data recorded from 1985 to 2016 from a dozen ground-based sites have been analyzed, mostly between 30 and 67° N. At clean-air sites such as Alaska, Sweden, New Mexico, or the mountains of California, the ethene columns were always less than 1 × 1015 molec cm-2 and therefore undetectable. In urban sites such as JPL, California, ethene was measurable with column amounts of 20 × 1015 molec cm-2 observed in the 1990s. Despite the increasing population and traffic in southern California, a factor 3 decrease in ethene column density is observed over JPL over the past 25 years, accompanied by a decrease in CO. This is likely due to southern California's increasingly stringent vehicle exhaust regulations and tighter enforcement over this period.

  2. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

  3. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

  4. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

  5. Laser-Excited Atomic Fluorescence and Ionization in a Graphite Furnace for the Determination of Metals and Nonmetals

    NASA Astrophysics Data System (ADS)

    Butcher, David James

    1990-01-01

    Here is reported novel instrumentation for atomic spectrometry that combined the use of a pulsed laser system as the light source and an electrothermal atomizer as the atom cell. The main goal of the research was to develop instrumentation that was more sensitive for elemental analysis than commercially available instruments and could be used to determine elements in real sample matrices. Laser excited atomic fluorescence spectrometry (LEAFS) in an electrothermal atomizer (ETA) was compared to ETA atomic absorption spectrometry (AAS) for the determination of thallium, manganese, and lead in food and agricultural standard reference materials (SRMs). Compared to ETA AAS, ETA LEAFS has a longer linear dynamic range (LDR) (5-7 orders of magnitude compared to 2-3 orders of magnitude) and higher sensitivity (10 ^{-16} to 10^{ -14} g as compared to 10^{ -13} to 10^{-11} g). Consequently, ETA LEAFS allows elemental analysis to be done over a wider range of concentrations with less dilution steps. Thallium was accurately determined in biological samples by ETA LEAFS at amounts five to one hundred times below the ETA AAS detection limit. ETA AAS and ETA LEAFS were compared for the determination of lead and manganese, and in general, the accuracies and precisions of ETA AAS were the same, with typical precisions between 3% and 6%. Fluorine was determined using laser excited molecular fluorescence spectrometry (LEMOFS) in an ETA. Molecular fluorescence from magnesium fluoride was collected, and the detection limit of 0.3 pg fluorine was two to six orders of magnitude more sensitive than other methods commonly used for the determination of fluorine. Significant interferences from ions were observed, but the sensitivity was high enough that fluorine could be determined in freeze dried urine SRMs by diluting the samples by a factor of one hundred to remove the interferences. Laser enhanced ionization (LEI) in an ETA was used for the determination of metals. For thallium, indium

  6. AA amyloidosis: Mount Sinai experience, 1997-2012.

    PubMed

    Bunker, Daniel; Gorevic, Peter

    2012-01-01

    AA amyloidosis is a systemic disease characterized by the extracellular deposition of amyloid fibrils derived from the acute-phase reactant serum amyloid A protein. It is typically a consequence of chronic inflammatory conditions like rheumatoid arthritis or Crohn's disease, although more patients are being identified who have more unusual causes or no known inflammatory stimulus. We performed a retrospective chart review of all patients with AA amyloidosis seen at Mount Sinai during the period of 1997-2012. Particular attention was paid to the patients' underlying diseases, extent of organ involvement, levels of inflammatory markers and proinflammatory cytokines, presence of pyrin gene mutations, and outcomes. Forty-three patients were seen at Mount Sinai with AA amyloidosis during this period. The most common underlying diseases were rheumatoid arthritis (21%) and Crohn's disease (16%), though 21% of patients were considered to have idiopathic AA amyloid after an extensive search found no underlying inflammatory disease. Almost all patients (95%) had renal involvement based on biopsy or clinical criteria, with 19 patients (44%) eventually requiring dialysis and 5 (12%) undergoing renal transplantation. Inflammatory markers were elevated in most patients; however, interleukin-6 was the only consistently elevated cytokine. Three patients (of 9 tested) were found to be positive for the E148Q pyrin gene mutation. Our study confirms the increasing number of patients being seen with idiopathic AA amyloidosis. More research is needed to determine if these patients have an underlying genetic susceptibility encoded in pyrin or other genes. Our study also confirms the dominance of renal disease in this population. The elevated levels of interleukin-6, in comparison with other cytokines, could represent a therapeutic target. © 2012 Mount Sinai School of Medicine.

  7. Increasing Protein Charge State When Using Laser Electrospray Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Karki, Santosh; Flanigan, Paul M.; Perez, Johnny J.; Archer, Jieutonne J.; Levis, Robert J.

    2015-05-01

    Femtosecond (fs) laser vaporization is used to transfer cytochrome c, myoglobin, lysozyme, and ubiquitin from the condensed phase into an electrospray (ES) plume consisting of a mixture of a supercharging reagent, m-nitrobenzyl alcohol ( m-NBA), and trifluoroacetic acid (TFA), acetic acid (AA), or formic acid (FA). Interaction of acid-sensitive proteins like cytochrome c and myoglobin with the highly charged ES droplets resulted in a shift to higher charge states in comparison with acid-stable proteins like lysozyme and ubiquitin. Laser electrospray mass spectrometry (LEMS) measurements showed an increase in both the average charge states (Zavg) and the charge state with maximum intensity (Zmode) for acid-sensitive proteins compared with conventional electrospray ionization mass spectrometry (ESI-MS) under equivalent solvent conditions. A marked increase in ion abundance of higher charge states was observed for LEMS in comparison with conventional electrospray for cytochrome c (ranging from 19+ to 21+ versus 13+ to 16+) and myoglobin (ranging from 19+ to 26+ versus 18+ to 21+) using an ES solution containing m-NBA and TFA. LEMS measurements as a function of electrospray flow rate yielded increasing charge states with decreasing flow rates for cytochrome c and myoglobin.

  8. Role and mechanism of AT1-AA in the pathogenesis of HELLP syndrome.

    PubMed

    Bu, Shurui; Wang, Yuxian; Sun, Shuqing; Zheng, Yanqian; Jin, Zhu; Zhi, Jianming

    2018-01-10

    HELLP syndrome remains a leading cause of maternal and neonatal mortality and morbidity worldwide, which symptoms include hemolysis, elevated liver enzymes and low platelet count. The objective of this study was to determine whether HELLP is associated with AT1-AA. The positive rate and titer of AT1-AA in plasma from pregnant women were determined, and the correlation of AT1-AA titer with the grade of HELLP was analyzed. A HELLP rat model established by intravenous injection of AT1-AA. Our experimental results show the AT1-AA titer and positive rate were significantly higher in HELLP group, and AT1-AA titer were positively correlated with the level of TNF-α and ET-1 in plasma and the grade of HELLP syndrome. The results of animal experiments showed that the typical features of HELLP in the pregnant rats after AT1-AA injection. The levels of TNF-α and ET-1 in plasma and liver tissue were significantly increased in AT1-AA-treated rats compared with control rats. The HELLP syndrome induced by AT1-AA was attenuated markedly after administration of losartan. These data support the hypothesis that one the potential pathway that AT1-AA induce damage to capillary endothelial cells and liver during pregnancy is through activation of TNF-α and ET-1.

  9. Surface tuning laser desorption/ionization mass spectrometry (STLDI-MS) for the analysis of small molecules using quantum dots.

    PubMed

    Abdelhamid, Hani Nasser; Chen, Zhen-Yu; Wu, Hui-Fen

    2017-08-01

    In most applications of quantum dots (QDs) for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS), one side of QDs is supported by a solid substrate (stainless - steel plate), whereas the other side is in contact with the target analytes. Therefore, the surface capping agent of QDs is a key parameter for laser desorption/ionization mass spectrometry (LDI-MS). Cadmium telluride quantum dots (CdTe QDs) modified with different capping agents are synthesized, characterized, and applied for surface tuning laser desorption/ionization mass spectrometry (STLDI-MS). Data shows that CdTe quantum dot modified cysteine (cys@CdTe QDs) has an absorption that matches with the wavelength of the N 2 laser (337 nm). The synergistic effect of large surface area and absorption of the laser irradiation of cys@CdTe QDs enhances the LDI-MS process for small - molecule analysis, including α-, β-, and γ-cyclodextrin, gramicidin D, perylene, pyrene, and triphenylphosphine. Cys@CdTe QDs are also applied using Al foils as substrates. Aluminum foil combined with cys@CdTe QDs enhances the ionization efficiency and is cheap compared to traditional matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with a stainless - steel plate.

  10. Determination of arsenic and cadmium in crude oil by direct sampling graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    de Jesus, Alexandre; Zmozinski, Ariane Vanessa; Damin, Isabel Cristina Ferreira; Silva, Márcia Messias; Vale, Maria Goreti Rodrigues

    2012-05-01

    In this work, a direct sampling graphite furnace atomic absorption spectrometry method has been developed for the determination of arsenic and cadmium in crude oil samples. The samples were weighed directly on the solid sampling platforms and introduced into the graphite tube for analysis. The chemical modifier used for both analytes was a mixture of 0.1% Pd + 0.06% Mg + 0.06% Triton X-100. Pyrolysis and atomization curves were obtained for both analytes using standards and samples. Calibration curves with aqueous standards could be used for both analytes. The limits of detection obtained were 5.1 μg kg- 1 for arsenic and 0.2 μg kg- 1 for cadmium, calculated for the maximum amount of sample that can be analyzed (8 mg and 10 mg) for arsenic and cadmium, respectively. Relative standard deviations lower than 20% were obtained. For validation purposes, a calibration curve was constructed with the SRM 1634c and aqueous standards for arsenic and the results obtained for several crude oil samples were in agreement according to paired t-test. The result obtained for the determination of arsenic in the SRM against aqueous standards was also in agreement with the certificate value. As there is no crude oil or similar reference material available with a certified value for cadmium, a digestion in an open vessel under reflux using a "cold finger" was adopted for validation purposes. The use of paired t-test showed that the results obtained by direct sampling and digestion were in agreement at a 95% confidence level. Recovery tests were carried out with inorganic and organic standards and the results were between 88% and 109%. The proposed method is simple, fast and reliable, being appropriated for routine analysis.

  11. Determination of cadmium and lead in table salt by sequential multi-element flame atomic absorption spectrometry.

    PubMed

    Amorim, Fábio A C; Ferreira, Sérgio L C

    2005-02-28

    In the present paper, a simultaneous pre-concentration procedure for the sequential determination of cadmium and lead in table salt samples using flame atomic absorption spectrometry is proposed. This method is based on the liquid-liquid extraction of cadmium(II) and lead(II) ions as dithizone complexes and direct aspiration of the organic phase for the spectrometer. The sequential determination of cadmium and lead is possible using a computer program. The optimization step was performed by a two-level fractional factorial design involving the variables: pH, dithizone mass, shaking time after addition of dithizone and shaking time after addition of solvent. In the studied levels these variables are not significant. The experimental conditions established propose a sample volume of 250mL and the extraction process using 4.0mL of methyl isobutyl ketone. This way, the procedure allows determination of cadmium and lead in table salt samples with a pre-concentration factor higher than 80, and detection limits of 0.3ngg(-1) for cadmium and 4.2ngg(-1) for lead. The precision expressed as relative standard deviation (n = 10) were 5.6 and 2.6% for cadmium concentration of 2 and 20ngg(-1), respectively, and of 3.2 and 1.1% for lead concentration of 20 and 200ngg(-1), respectively. Recoveries of cadmium and lead in several samples, measured by standard addition technique, proved also that this procedure is not affected by the matrix and can be applied satisfactorily for the determination of cadmium and lead in saline samples. The method was applied for the evaluation of the concentration of cadmium and lead in table salt samples consumed in Salvador City, Bahia, Brazil.

  12. An Existential Approach: An Alternative to the AA Model of Recovery

    ERIC Educational Resources Information Center

    Rogers, Maria A.; Cobia, Debra

    2008-01-01

    Alcoholics Anonymous (AA) is the most widely used organization for the treatment of alcoholism. AA's philosophy has changed how many people view themselves and their substance use. The majority of substance abuse programs in the United States use the 12 steps, either by making them the basis of their treatment program, or by introducing AA to…

  13. [Determination of aluminum in sediments by atomic absorption spectrophotometer without FIA spectrophotometric analysis].

    PubMed

    Zhao, Zhen-yi; Han, Guang-xi; Song, Xi-ming; Luo, Zhi-xiong

    2008-06-01

    To search for a new method of determining, we developed a new flow injection analyzer, applied to the atomic absorption spectrophotometer, relying on it without flame in place of visible spectrophotometer, and studied the appropriate condition for the determination of aluminum in sediments, thus built up a kind of new analytical test technique. Three peak and two valley absorption values (A1, A2, A3, A4 and A5) can be continuously obtained simultaneously that all can be used for quantitative analysis, then we discussed its theory and experiment technique. Based on the additivity of absorbance (A = A1+A2+A3+A4+ A5), the sensitivity of FIA is enhanced, and its precision and linear relation are also good, raising the efficiency of AAS. The simple method has been applied to determining Al in sediments, and the results are satisfactory.

  14. Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease

    PubMed Central

    Zhang, Beiru; Une, Yumi; Fu, Xiaoying; Yan, Jingmin; Ge, FengXia; Yao, Junjie; Sawashita, Jinko; Mori, Masayuki; Tomozawa, Hiroshi; Kametani, Fuyuki; Higuchi, Keiichi

    2008-01-01

    AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine·HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction. PMID:18474855

  15. Determination of free and total sulfur(IV) compounds in coconut water using high-resolution continuum source molecular absorption spectrometry in gas phase.

    PubMed

    Oliveira, Michael L; Brandao, Geovani C; de Andrade, Jailson B; Ferreira, Sergio L C

    2018-03-01

    This work proposes a method for the determination of free and total sulfur(IV) compounds in coconut water samples, using the high-resolution continuum source molecular absorption spectrometry. It is based on the measurement of the absorbance signal of the SO 2 gas generate, which is resultant of the addition of hydrochloric acid solution on the sample containing the sulfating agent. The sulfite bound to the organic compounds is released by the addition of sodium hydroxide solution, before the generation of the SO 2 gas. The optimization step was performed using multivariate methodology involving volume, concentration and flow rate of hydrochloric acid. This method was established by the sum of the absorbances obtained in the three lines of molecular absorption of the SO 2 gas. This strategy allowed a procedure for the determination of sulfite with limits of detection and quantification of 0.36 and 1.21mgL -1 (for a sample volume of 10mL) and precision expressed as relative standard deviation of 5.4% and 6.4% for a coconut water sample containing 38.13 and 54.58mgL -1 of free and total sulfite, respectively. The method was applied for analyzing five coconut water samples from Salvador city, Brazil. The average contents varied from 13.0 to 55.4mgL -1 for free sulfite and from 24.7 to 66.9mgL -1 for total sulfur(IV) compounds. The samples were also analyzed employing the Ripper´s procedure, which is a reference method for the quantification of this additive. A statistical test at 95% confidence level demonstrated that there is no significant difference between the results obtained by the two methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Acrylamide: formation, occurrence in food products, detection methods, and legislation.

    PubMed

    Arvanitoyannis, Ioannis S; Dionisopoulou, Niki

    2014-01-01

    This review aims at summarizing the most recent updates in the field of acrylamide (AA) formation (mechanism, conditions) and the determination of AA in a number of foods (fried or baked potatoes, chips, coffee, bread, etc). The methods applied for AA detection [Capillary Electrophoresis-Mass Spectrometry (CE-MS), Liquid Chromatography-Mass Spectrometry (LC-MS), Non-Aqueous Capillary Electrophoresis (NACE), High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), Pressurized Fluid Extraction (PFE), Matrix Solid-Phase Dispersion (MSPD), Gas Chromatography-Mass Spectrometry (GC-MS), Solid-Phase MicroExtraction-Gas Chromatography (SPME-GC), Enzyme Linked Immunosorbent Assay (ELISA), and MicroEmulsion ElectroKinetic Chromatography (MEEKC) are presented and commented. Several informative figures and tables are included to show the effect of conditions (temperature, time) on the AA formation. A section is also included related to AA legislation in EU and US.

  17. Through-thickness recrystallization characteristics of a laminated AA3xxx–AA6xxx aluminum alloy system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liao, L.H., E-mail: l2liao@uwaterloo.ca; Jin, H.; Gallerneault, M.

    2015-03-15

    The through-thickness annealing behavior of a laminated AA3xxx–AA6xxx alloy system at 300 °C has been studied by scanning electron microscopy, electron backscatter diffraction analysis, electron probe micro-analysis, differential scanning calorimetry, and hardness measurement. Results show that the recrystallization process starts at the interface region between the AA3xxx (clad) and AA6xxx (core) layers. Subsequently, the recrystallization process front progresses into the core layer, while the clad layer is the last region to recrystallize. It is also found that precipitation precedes recrystallization in the entire laminate at the investigated temperature. The preferential onset of recrystallization at the interface region is attributed tomore » the net driving pressure being the highest in this region. The factors that lead to such enhanced net driving pressure are (a) deformation incompatibility between the two alloy layers, (b) lower solute content of the interface, which also leads to lower volume fraction of precipitates, and (c) an accelerated rate of precipitate coarsening due to the presence of a higher density of dislocations. The gradual progress of recrystallization from the interface towards the core layer is dictated by precipitate coarsening and the dependence of its rate on the density of deformation-induced dislocations. The lower driving pressure due to lower work hardening capacity, high solute drag pressure due to Mn, and additional Zener drag from precipitates that form due to solute redistribution during annealing explain the late initiation of recrystallization in the clad layer. - Highlights: • The through-thickness recrystallization of a laminated system is investigated. • The early onset of recrystallization at the interface is discussed. • The effects of precipitation and coarsening on recrystallization are analyzed.« less

  18. A dispersive liquid--liquid microextraction methodology for copper (II) in environmental samples prior to determination using microsample injection flame atomic absorption spectrometry.

    PubMed

    Alothman, Zeid A; Habila, Mohamed; Yilmaz, Erkan; Soylak, Mustafa

    2013-01-01

    A simple, environmentally friendly, and efficient dispersive liquid-liquid microextraction method combined with microsample injection flame atomic absorption spectrometry was developed for the separation and preconcentration of Cu(II). 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP) was used to form a hydrophobic complex of Cu(II) ions in the aqueous phase before extraction. To extract the Cu(II)-5-Br-PADAP complex from the aqueous phase to the organic phase, 2.0 mL of acetone as a disperser solvent and 200 microL of chloroform as an extraction solvent were used. The influences of important analytical parameters, such as the pH, types and volumes of the extraction and disperser solvents, amount of chelating agent, sample volume, and matrix effects, on the microextraction procedure were evaluated and optimized. Using the optimal conditions, the LOD, LOQ, preconcentration factor, and RSD were determined to be 1.4 microg/L, 4.7 microg/L, 120, and 6.5%, respectively. The accuracy of the proposed method was investigated using standard addition/recovery tests. The analysis of certified reference materials produced satisfactory analytical results. The developed method was applied for the determination of Cu in real samples.

  19. Ultrasound-Assisted Emulsification Microextraction Based on Solidification Floating Organic Drop Trace Amounts of Manganese Prior to Graphite Furnace Atomic Absorption Spectrometry Determination

    PubMed Central

    Mohadesi, Alireza; Falahnejad, Masoumeh

    2012-01-01

    In the present study, an ultrasound-assisted emulsification microextraction based on solidification floating organic drop method is described for preconcentration of trace amounts of Mn (II). 2-(5-Bromo-2-pyridylazo)-5 diethylaminophenol was added to a solution of Mn+2 at ph = 10.0. After this, 1-undecanol was added to the solution as an extraction solvent, and solution was stirred. Several factors influencing the microextraction efficiency, such as pH, the amount of chelating agent, nature and volume of extraction solvent, the volume of sample solution, stirring rate, and extraction time were investigated and optimized. Then sample vial was cooled by inserting into an ice bath, and the solidified was transferred into a suitable vial for immediate melting. Finally the sample was injected into a graphite furnace atomic absorption spectrometry. Under the optimum condition the linear dynamic range was 0.50–10.0 ng mL−1 with a correlation coefficient of 0.9926, and the detection limit of 0.3 ng mL−1 was obtained. The enrichment factor was 160. The proposed method was successfully applied for separation and determination of manganese in sea, rain, tap, and river water samples. PMID:22645504

  20. COACTIVATOR ACTIVATOR (CoAA) PREVENTS THE TRANSCRIPTIONAL ACTIVITY OF RUNT DOMAIN TRANSCRIPTION FACTORS

    PubMed Central

    Li, Xiaodong; Hoeppner, Luke H.; Jensen, Eric D.; Gopalakrishnan, Rajaram; Westendorf, Jennifer J.

    2013-01-01

    Runx proteins are essential for a number of developmental processes and are aberrantly expressed in many human cancers. Runx factors bind DNA and co-factors to activate or repress genes crucial for bone formation, hematopoiesis, and neuronal development. Co-activator activator (CoAA) is a nuclear protein that regulates gene expression, RNA splicing and is overexpressed in many human tumors. In this study, we identified CoAA as a Runx2 binding protein. CoAA repressed Runx factor-dependent activation of reporter genes in a histone deacetylase-independent manner. CoAA also blocked Runx2-mediated repression of the Axin2 promoter, a novel Runx target gene. The carboxy-terminus of CoAA is essential for binding the Runt domains of Runx1 and Runx2. In electophoretic mobility shift assays, CoAA inhibited Runx2 interactions with DNA. These data indicate that CoAA is an inhibitor of Runx factors and can negate Runx factor regulation of gene expression. CoAA is expressed at high levels in human fetal osteoblasts and osteosarcoma cell lines. Suppression of CoAA expression by RNA interference reduced osteosarcoma cell viability in vitro, suggesting that it contributes to the proliferation and/or survival of osteoblast lineage cells. PMID:19585539

  1. AaCAT1 of the Yellow Fever Mosquito, Aedes aegypti

    PubMed Central

    Hansen, Immo A.; Boudko, Dmitri Y.; Shiao, Shin-Hong; Voronov, Dmitri A.; Meleshkevitch, Ella A.; Drake, Lisa L.; Aguirre, Sarah E.; Fox, Jeffrey M.; Attardo, Geoffrey M.; Raikhel, Alexander S.

    2011-01-01

    Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to l-histidine at neutral pH (K0.5l-His = 0.34 ± 0.07 mm, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His+-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues. PMID:21262963

  2. High-precision measurement of phenylalanine δ15N values for environmental samples: a new approach coupling high-pressure liquid chromatography purification and elemental analyzer isotope ratio mass spectrometry.

    PubMed

    Broek, Taylor A B; Walker, Brett D; Andreasen, Dyke H; McCarthy, Matthew D

    2013-11-15

    Compound-specific isotope analysis of individual amino acids (CSI-AA) is a powerful new tool for tracing nitrogen (N) source and transformation in biogeochemical cycles. Specifically, the δ(15)N value of phenylalanine (δ(15)N(Phe)) represents an increasingly used proxy for source δ(15)N signatures, with particular promise for paleoceanographic applications. However, current derivatization/gas chromatography methods require expensive and relatively uncommon instrumentation, and have relatively low precision, making many potential applications impractical. A new offline approach has been developed for high-precision δ(15)N measurements of amino acids (δ(15)N(AA)), optimized for δ(15)N(Phe) values. Amino acids (AAs) are first purified via high-pressure liquid chromatography (HPLC), using a mixed-phase column and automated fraction collection. The δ(15)N values are determined via offline elemental analyzer-isotope ratio mass spectrometry (EA-IRMS). The combined HPLC/EA-IRMS method separated most protein AAs with sufficient resolution to obtain accurate δ(15)N values, despite significant intra-peak isotopic fractionation. For δ(15)N(Phe) values, the precision was ±0.16‰ for standards, 4× better than gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS; ±0.64‰). We also compared a δ(15)N(Phe) paleo-record from a deep-sea bamboo coral from Monterey Bay, CA, USA, using our method versus GC/C/IRMS. The two methods produced equivalent δ(15)N(Phe) values within error; however, the δ(15)N(Phe) values from HPLC/EA-IRMS had approximately twice the precision of GC/C/IRMS (average stdev of 0.27‰ ± 0.14‰ vs 0.60‰ ± 0.20‰, respectively). These results demonstrate that offline HPLC represents a viable alternative to traditional GC/C/IMRS for δ(15)N(AA) measurement. HPLC/EA-IRMS is more precise and widely available, and therefore useful in applications requiring increased precision for data interpretation (e.g. δ(15)N paleoproxies

  3. AA amyloidosis complicating the hereditary periodic fever syndromes.

    PubMed

    Lane, Thirusha; Loeffler, Jutta M; Rowczenio, Dorota M; Gilbertson, Janet A; Bybee, Alison; Russell, Tonia L; Gillmore, Julian D; Wechalekar, Ashutosh D; Hawkins, Philip N; Lachmann, Helen J

    2013-04-01

    AA amyloidosis is a life-threatening complication of the hereditary periodic fever syndromes (HPFS), which are otherwise often compatible with normal life expectancy. This study was undertaken to determine the characteristics, presentation, natural history, and response to treatment in 46 patients who had been referred for evaluation at the UK National Amyloidosis Centre. Disease activity was monitored by serial measurement of serum amyloid A. Renal function was assessed by measurement of serum creatinine and albumin levels, the estimated glomerular filtration rate, and proteinuria from 24-hour urine collections. The amyloid load was measured by serum amyloid P scintigraphy. Twenty-four patients had familial Mediterranean fever, 12 patients had tumor necrosis factor receptor-associated periodic syndrome, 6 patients had cryopyrin-associated periodic syndromes, and 4 patients had mevalonate kinase deficiency. The median age at onset of HPFS was 5 years; median age at presentation with AA amyloidosis was 38 years. Diagnosis of an HPFS had not been considered prior to presentation with AA amyloidosis in 23 patients (50%). Eleven patients (24%) had end-stage renal failure (ESRF) at presentation; of these, 3 had received transplants prior to referral. A further 13 patients developed ESRF over the followup period, with 10 undergoing renal transplantation. The median time to progression to ESRF from onset of AA amyloidosis was 3.3 years (interquartile range [IQR] 2-8), with a median time to transplant of 4 years (IQR 3-6). Eleven patients (24%) died. The median survival in the entire cohort was 19 years from diagnosis of AA amyloidosis. Of the 37 patients who were treated successfully, or in whom at least partial suppression of the underlying HPFS was achieved, 17 (46%) showed amyloid regression, 14 (38%) showed a stable amyloid load, and 2 (5%) showed increased amyloid deposition over the followup period. AA amyloidosis remains a challenging and serious late complication

  4. Determination of Volatiles by Odor Activity Value and Phenolics of cv. Ayvalik Early-Harvest Olive Oil

    PubMed Central

    Guclu, Gamze; Sevindik, Onur; Kelebek, Hasim; Selli, Serkan

    2016-01-01

    Ayvalik is an important olive cultivar producing high quality oils in Turkey. In the present study, volatile and phenolic compositions of early-harvest extra virgin olive oil (cv. Ayvalik) were determined. The solvent-assisted flavor evaporation (SAFE) technique was used for the extraction of volatile components. The aromatic extract obtained by SAFE was representative of the olive oil odor. A total of 32 aroma compounds, including alcohols, aldehydes, terpenes, esters, and an acid, were identified in the olive oil. Aldehydes and alcohols were qualitatively and quantitatively the most dominant volatiles in the oil sample. Of these, six volatile components presented odor activity values (OAVs) greater than one, with (Z)-3-hexenal (green), hexanal (green-sweet) and nonanal (fatty-pungent) being those with the highest OAVs in olive oil. A total of 14 phenolic compounds were identified and quantified by liquid chromatography combined with a diode array detector and ion spray mass spectrometry. The major phenolic compounds were found as 3,4-DHPEA-EDA, 3,4-DHPEA-EA and p-HPEA-EDA. PMID:28231141

  5. [Regularity of Clinical Application of Lianquan (CV 23) in Chinese Ancient Times According to Literature of Traditional Chinese Medicine].

    PubMed

    Deng, Mei-Jun; Liu, Chun-Yan; Xie, Yu; Zhu, Jie-Bin; Xu, Zhen-Hua

    2018-03-25

    To summarize the regularity of application of Lianquan (CV 23) in clinical practice in Chinese ancient times through analysis of ancient traditional Chinese medical (TCM) literature. A total of 60 books involving CV 23 from the 1 156 ancient TCM books listed in the fifth edition of Encyclopedia of Traditional Chinese Medicine were collected by using CV 23 as the main keyword and "Sheben" "Benchi", and "Jieben" (the other names of CV 23 in TCM)as the supplementary keywords and analyzed systematically. A database was then constructed from the collected data, including the related types of disorders or symptoms, acupoint recipes, and methods of needling and moxibustion, contraindications, etc. A total of 196 articles related to the application of CV 23 from 60 ancient classical books were collected in accordance with the inclusive criteria. Among them, 155 articles are referred to the indications of CV 23, 35 to types of disorders such as asthma, cough, tongue swelling with difficulty in speaking, protracted tongue, acute contraction of tongue root, vomiting, spasm syndrome, stroke, aphtha, problems of mouth and teeth, throat problems, etc. of the internal medicine, surgery, pediatrics, and five-sense organs; 64 items are referred to the application of single CV 23, 91 to CV 23-included recipes containing 111 adjunct acupoints, and 78 to stimulation of CV 23 with acupuncture needle, moxibustion, pricking blood, and fire needle. Moreover, of the 111 adjunct acupoints, the most commonly used are Shaoshang (LU 11), Tiantu (CV 22), Hegu (LI 4), Yuye (EX-HN 13), Zhongchong (PC 9), etc. Lianquan (CV 23) is mainly used for glossopharyngeal problems chiefly by syndrome-meridian differentiation. The supplement of complementary acupoints or five-shu points in combination with CV 23 has a synergistic effect. Moxibustion (3 moxa- cones in general) is often employed, and the needling depth is usually about 7.5 mm. The common contraindication of CV 23 is severe tongue swelling.

  6. MIZEX, 1984, NASA CV-990 flight report

    NASA Technical Reports Server (NTRS)

    1985-01-01

    During June/July 1984, the NASA CV-990 Airborne Laboratory was utilized in a mission to overly the Fram Strait/East Greenland Sea marginal ice zone (MIZ) during the main summer marginal ice zone experiment (MIZEX '84). The eight data flights were coordinated where possible with overpasses of the Nimbus-7 satellite, and with measurement of sea ice, open ocean, and atmospheric properties at the surface. The surface research teams were based on seven research vessels, some with helicopters: (1) M/V Kvitbjorn, (2) M/V Polarqueen; (3) M/S Haakon Mosby; (4) a M/S H.U. Sverdrup, all from Norway; (5) F/S Polarstern from the Federal Republic of Germany; and (6) the USNS Lynch from the USA. There were also coordinated flights with the NRL P3, NOAA P3, Canadian CV580, and the French B-17 during the overlap portions of their respective missions. Analysis of the real-time data acquired during the mission and uncalibrated data stored on tape has served to indicate the mission was over 90% successful.

  7. Application of l-cystine modified zeolite for preconcentration and determination of ultra-trace levels of cadmium by flame atomic absorption spectrometry.

    PubMed

    Rezvani, Seyyed Ahmad; Soleymanpour, Ahmad

    2016-03-04

    A very convenient, sensitive and precise solid phase extraction (SPE) system was developed for enrichment and determination of ultra-trace of cadmium ion in water and plant samples. This method was based on the retention of cadmium(II) ions by l-cystine adsorbed in Y-zeolite and carry out in a packed mini-column. The retained cadmium ions then were eluted and determined by flame atomic absorption spectrometry. The scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy techniques were applied for the characterization of cystine modified zeolite (CMZ). Some experimental conditions affecting the analytical performance such as pH, eluent type, concentration of sample, eluent flow rate and also the presence of interfering ions were investigated. The calibration graph was linear within the range of 0.1-7.5ngmL(-1) and limit of detection was obtained 0.04ngmL(-1) with the preconcentration factor of 400. The relative standard deviation (RSD) was obtained 1.4%, indicating the excellent reproducibility of this method. The proposed method was successfully applied for the extraction and determination of cadmium(II) ion in black tea, cigarette's tobacco and also various water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Use of slurry sampling for the direct determination of zinc in yogurt by high resolution-continuum source flame atomic absorption spectrometry.

    PubMed

    Brandao, Geovani C; de Jesus, Raildo M; da Silva, Erik G P; Ferreira, Sergio L C

    2010-06-15

    This paper presents an analytical procedure for the direct determination of zinc in yogurt employing sampling slurry and high resolution-continuum source flame atomic absorption spectrometry (HR-CS FAAS). The step optimization established the experimental conditions of: 2.0molL(-1) hydrochloric acid, a sonication time of 20min and a sample mass of 1.0g for a slurry volume of 25mL. This method allows the determination of zinc with a limit of quantification of 0.32microgg(-1). The precision expressed as relative standard deviation (RSD) were 0.82 and 2.08% for yogurt samples containing zinc concentrations of 4.85 and 2.49microgg(-1), respectively. The accuracy was confirmed by the analysis of a certified reference material of non-fat milk powder furnished by the National Institute of Standard and Technology. The proposed method was applied for the determination of zinc in seven yogurt samples. The zinc content was varied from 2.19 to 4.85microgg(-1). These results agreed with those reported in the literature. The samples were also analyzed after acid digestion and zinc determination by FAAS. No statistical difference was observed between the results obtained by both of the procedures performed.

  9. Isolation and Characterization of CvIV4: A Pain Inducing α- Scorpion Toxin

    PubMed Central

    Rowe, Ashlee H.; Xiao, Yucheng; Scales, Joseph; Linse, Klaus D.; Rowe, Matthew P.; Cummins, Theodore R.; Zakon, Harold H.

    2011-01-01

    Background Among scorpion species, the Buthidae produce the most deadly and painful venoms. However, little is known regarding the venom components that cause pain and their mechanism of action. Using a paw-licking assay (Mus musculus), this study compared the pain-inducing capabilities of venoms from two species of New World scorpion (Centruroides vittatus, C. exilicauda) belonging to the neurotoxin-producing family Buthidae with one species of non-neurotoxin producing scorpion (Vaejovis spinigerus) in the family Vaejovidae. A pain-inducing α-toxin (CvIV4) was isolated from the venom of C. vittatus and tested on five Na+ channel isoforms. Principal Findings C. vittatus and C. exilicauda venoms produced significantly more paw licking in Mus than V. spinigerus venom. CvIV4 produced paw licking in Mus equivalent to the effects of whole venom. CvIV4 slowed the fast inactivation of Nav1.7, a Na+ channel expressed in peripheral pain-pathway neurons (nociceptors), but did not affect the Nav1.8-based sodium currents of these neurons. CvIV4 also slowed the fast inactivation of Nav1.2, Nav1.3 and Nav1.4. The effects of CvIV4 are similar to Old World α-toxins that target Nav1.7 (AahII, BmK MI, LqhIII, OD1), however the primary structure of CvIV4 is not similar to these toxins. Mutant Nav1.7 channels (D1586A and E1589Q, DIV S3–S4 linker) reduced but did not abolish the effects of CvIV4. Conclusions This study: 1) agrees with anecdotal evidence suggesting that buthid venom is significantly more painful than non-neurotoxic venom; 2) demonstrates that New World buthids inflict painful stings via toxins that modulate Na+ channels expressed in nociceptors; 3) reveals that Old and New World buthids employ similar mechanisms to produce pain. Old and New World α-toxins that target Nav1.7 have diverged in sequence, but the activity of these toxins is similar. Pain-inducing toxins may have evolved in a common ancestor. Alternatively, these toxins may be the product of convergent

  10. ES4 NPP-FM5 Ed1-CV

    Atmospheric Science Data Center

    2018-06-11

    ... Data Products Catalog:  DPC ES4 R7V1  (PDF) Validation Graphics Readme Files:  Readme R6V1-894 ... Data:  Note:  Edition1-CV is for instrument validation purposes only and not suited for science publications. ...

  11. Determination of sulfur in kerosene by combustion and molecular absorption spectrometry in the gas phase

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ruschak, M.L.; Syty, A.

    1982-08-01

    A technique of nonflame molecular adsorption in the gas phase developed for the determination of sulfite trapped in tetrachloromercurate, is described herein for application to the determination of total sulfur in kerosene. The burner head is removed from the atomic absorption spectrometer and replaced with a flow-through absorption cell. A special reaction vessel is used to evolve SO/sub 2/ from the sulfite in a precise and convenient manner. The transient absorbance caused by the SO/sub 2/, as it is carried through the absorption cell, is measured. Both spiked and unspiked samples of kerosene were analyzed, and the reproducibility of themore » repeated runs is evidenced by a relative standard deviation from the mean of 5% for the unspiked kerosene and 4% for the spiked kerosene. If the detection level is defined as that concentration of S which gives a % S twice the standard deviation from the mean yields, the detection limit for the present method is 0.002% S by weight in kerosene.« less

  12. The draft genome of Corchorus olitorius cv. JRO-524 (Navin).

    PubMed

    Sarkar, Debabrata; Mahato, Ajay Kumar; Satya, Pratik; Kundu, Avijit; Singh, Sangeeta; Jayaswal, Pawan Kumar; Singh, Akshay; Bahadur, Kaushlendra; Pattnaik, Sasmita; Singh, Nisha; Chakraborty, Avrajit; Mandal, Nur Alam; Das, Debajeet; Basu, Tista; Sevanthi, Amitha Mithra; Saha, Dipnarayan; Datta, Subhojit; Kar, Chandan Sourav; Mitra, Jiban; Datta, Karabi; Karmakar, Pran Gobinda; Sharma, Tilak Raj; Mohapatra, Trilochan; Singh, Nagendra Kumar

    2017-06-01

    Here, we present the draft genome (377.3 Mbp) of Corchorus olitorious cv. JRO-524 (Navin), which is a leading dark jute variety developed from a cross between African (cv. Sudan Green) and indigenous (cv. JRO-632) types. We predicted from the draft genome a total of 57,087 protein-coding genes with annotated functions. We identified a large number of 1765 disease resistance-like and defense response genes in the jute genome. The annotated genes showed the highest sequence similarities with that of Theobroma cacao followed by Gossypium raimondii . Seven chromosome-scale genetically anchored pseudomolecules were constructed with a total size of 8.53 Mbp and used for synteny analyses with the cocoa and cotton genomes. Like other plant species, gypsy and copia retrotransposons were the most abundant classes of repeat elements in jute. The raw data of our study are available in SRA database of NCBI with accession number SRX1506532. The genome sequence has been deposited at DDBJ/EMBL/GenBank under the accession LLWS00000000, and the version described in this paper will be the first version (LLWS01000000).

  13. Using CV-GLUE procedure in analysis of wetland model predictive uncertainty.

    PubMed

    Huang, Chun-Wei; Lin, Yu-Pin; Chiang, Li-Chi; Wang, Yung-Chieh

    2014-07-01

    This study develops a procedure that is related to Generalized Likelihood Uncertainty Estimation (GLUE), called the CV-GLUE procedure, for assessing the predictive uncertainty that is associated with different model structures with varying degrees of complexity. The proposed procedure comprises model calibration, validation, and predictive uncertainty estimation in terms of a characteristic coefficient of variation (characteristic CV). The procedure first performed two-stage Monte-Carlo simulations to ensure predictive accuracy by obtaining behavior parameter sets, and then the estimation of CV-values of the model outcomes, which represent the predictive uncertainties for a model structure of interest with its associated behavior parameter sets. Three commonly used wetland models (the first-order K-C model, the plug flow with dispersion model, and the Wetland Water Quality Model; WWQM) were compared based on data that were collected from a free water surface constructed wetland with paddy cultivation in Taipei, Taiwan. The results show that the first-order K-C model, which is simpler than the other two models, has greater predictive uncertainty. This finding shows that predictive uncertainty does not necessarily increase with the complexity of the model structure because in this case, the more simplistic representation (first-order K-C model) of reality results in a higher uncertainty in the prediction made by the model. The CV-GLUE procedure is suggested to be a useful tool not only for designing constructed wetlands but also for other aspects of environmental management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Synthesize of silver-nanoparticles by plant extract and its application for preconcentration of cadmium followed by flame atomic absorption spectrometry.

    PubMed

    Almertaha, Abdul-Hossein; Eftekhari, Mohammad; Chamsaz, Mahmoud; Gheibi, Mohammad

    2018-02-02

    In this paper, Mentha pulegium leaves extract was used as a green reducing agent for the synthesis of silver-nanoparticles. The synthesized silver-nanoparticles were characterized by UV-VIS spectrophotometry, transmission electron microscopy, X-ray spectroscopy and used as an adsorbent for preconcentration of trace levels of cadmium (ІІ). After the desorption of cadmium (ІІ) in 5 mol L -1 formic acid, the desorbent solution was aspirated into the flame atomic absorption spectrometry for the determination of cadmium. In order to optimize the experimental condition, a response surface methodology based on central composite design was used. The optimum conditions are: pH: 8.6, amounts of adsorbent: 30 mg, 10 min extraction time and desorption time of 2 min. Under the optimum condition, the calibration curve was linear in the range of 5-200 μg L -1 cadmium (ІІ) ion with a correlation coefficient of 0.9995. The limit of detection was 1.1 μg L -1 and the relative standard deviation for 25 μg L -1 cadmium (ІІ) ion was 3.0% (n = 5). In order to check the applicability of the proposed method, different real samples were analyzed. Also, the accuracy of this method was successfully checked by the analysis of certified reference material and spike tests.

  15. Evaluation of ammonia as diluent for serum sample preparation and determination of selenium by graphite furnace atomic absorption spectrometry*1

    NASA Astrophysics Data System (ADS)

    Hernández-Caraballo, Edwin A.; Burguera, Marcela; Burguera, José L.

    2002-12-01

    A method for the determination of total selenium in serum samples by graphite furnace atomic absorption spectrometry was evaluated. The method involved direct introduction of 1:5 diluted serum samples (1% v/v NH 4OH+0.05% w/v Triton X-100 ®) into transversely heated graphite tubes, and the use of 10 μg Pd+3 μg Mg(NO 3) 2 as chemical modifier. Optimization of the modifier mass and the atomization temperature was conducted by simultaneously varying such parameters and evaluating both the integrated absorbance and the peak height/peak area ratio. The latter allowed the selection of compromise conditions rendering good sensitivity and adequate analyte peak profiles. A characteristic mass of 49 pg and a detection limit (3s) of 6 μg 1 -1 Se, corresponding to 30 μg l -1 Se in the serum sample, were obtained. The analyte addition technique was used for calibration. The accuracy was assessed by the determination of total selenium in Seronorm™ Trace Elements Serum Batch 116 (Nycomed Pharma AS). The method was applied for the determination of total selenium in ten serum samples taken from individuals with no known physical affection. The selenium concentration ranged between 79 and 147 μg l -1, with a mean value of 114±22 μg l -1.

  16. Determination of metals in lubricating oils by flame atomic absorption spectrometry using a single-bore high-pressure pneumatic nebulizer.

    PubMed

    Mora, J; Todolí, J L; Sempere, F J; Canals, A; Hernandis, V

    2000-12-01

    The behaviour of a single-bore high-pressure pneumatic nebulizer (SBHPPN) as a tool for the analysis of lubricating oils by flame atomic absorption spectrometry (FAAS) was investigated. The effects of the sample oil content [from 10% to 100% (w/w) oil in 4-methylpentan-2-one, IBMK] and the carrier nature (IBMK and methanol) on the characteristics of the aerosols generated, on the analyte transport efficiency and on the analytical figures of merit in FAAS were studied. A pneumatic concentric nebulizer (PCN) was used for comparison. Increasing the oil content increases the viscosity of the sample. With the PCN this gives rise to coarser aerosols, making it impossible to nebulize samples with an oil content higher than 70% (w/w). Using the SBHPPN, the viscosity of the sample scarcely affects the characteristics of the primary aerosols. Hence, the SBHPPN is able, by using the appropriate carrier, to nebulize pure lubricating oils. Among the carriers tested, IBMK is the most advisable because it is fully miscible with all the oil samples. The SBHPPN provides higher sensitivities and lower limits of detection than the PCN. Compared with a method based on organic dilution, the use of the SBHPPN for the direct analysis of lubricating oils by FAAS makes it possible, in addition to increasing the analysis throughput, to detect elements at lower concentrations. Moreover, the SBHPPN provides similar results to those obtained using a previous acid digestion step.

  17. U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR EXTRACTION OF METALS FROM SOIL, DUST, AIR FILTER, AND SURFACE AND DERMAL WIPE SAMPLES FOR AA (GRAPHITE FURNACE OR FLAME) OR ICP-AES ANALYSIS (BCO-L-3.1)

    EPA Science Inventory

    The purpose of this SOP is to describe the acid digestion of soil, house dust, air filter, and surface or dermal wipe samples for analysis using inductively coupled plasma atomic emissions spectrometry (ICP-AES) and/or graphite furnace atomic absorption spectrometry (GFAAS) or fl...

  18. An Analysis of the Rise and Fall of the AA-MAS Policy

    ERIC Educational Resources Information Center

    Lazarus, Sheryl S.; Thurlow, Martha L.; Ysseldyke, James E.; Edwards, Lynn M.

    2015-01-01

    In 2005, to address concerns about students who might fall in the "gap" between the regular assessment and the alternate assessment based on alternate achievement standards (AA-AAS), the U.S. Department of Education announced that states could develop alternate assessments based on modified achievement standards (AA-MAS). This article…

  19. Simultaneous determination of iron, cadmium, zinc, copper, nickel, lead, and uranium in seawater by stable isotope dilution spark source mass spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mykytiuk, A.P.; Russell, D.S.; Sturgeon, R.E.

    Trace concentrations (ng/mL) of Fe, Cd, Zn, Cu, Ni, Pb, U, and Co have been determined in seawater by stable isotope dilution spark source mass spectrometry. The seawater samples were preconcentrated on the ion exchanger Chelex-100 and the concentrate was evaporated on a graphite or silver electrode. The results are compared with those obtained by graphite furnace atomic absorption spectrometry and inductively coupled plasma emission spectrometry. The technique avoids the use of calibration standards and is capable of producing results in cases where the analyte is only partially recovered. 2 tables.

  20. Electric-field-induced plasmon in AA-stacked bilayer graphene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chuang, Y.C., E-mail: yingchih.chuang@gmail.com; Wu, J.Y., E-mail: yarst5@gmail.com; Lin, M.F., E-mail: mflin@mail.ncku.edu.tw

    2013-12-15

    The collective excitations in AA-stacked bilayer graphene for a perpendicular electric field are investigated analytically within the tight-binding model and the random-phase approximation. Such a field destroys the uniform probability distribution of the four sublattices. This drives a symmetry breaking between the intralayer and interlayer polarization intensities from the intrapair band excitations. A field-induced acoustic plasmon thus emerges in addition to the strongly field-tunable intrinsic acoustic and optical plasmons. At long wavelengths, the three modes show different dispersions and field dependence. The definite physical mechanism of the electrically inducible and tunable mode can be expected to also be present inmore » other AA-stacked few-layer graphenes. -- Highlights: •The analytical derivations are performed by the tight-binding model. •An electric field drives the non-uniformity of the charge distribution. •A symmetry breaking between the intralayer and interlayer polarizations is illustrated. •An extra plasmon emerges besides two intrinsic modes in AA-stacked bilayer graphene. •The mechanism of a field-induced mode is present in AA-stacked few-layer graphenes.« less

  1. Determination of total arsenic and arsenic(III) in phosphate fertilizers by hydride generation atomic absorption spectrometry after ultrasound-assisted extraction based on a control acid media.

    PubMed

    Rezende, Helen Cristine; Coelho, Nivia Maria Melo

    2014-01-01

    An ultrasound-assisted extraction procedure was developed for determination of inorganic arsenic (As) in phosphate fertilizer by hydride generation atomic absorption spectrometry. The variables that affect the hydride generation step were optimized, including the reducer, acid, sample flow rate, and concentrations of the acid and reducer. The determination of As(lll) was performed through the simple control of solution pH with a 0.5 M citric acid-sodium citrate buffer solution at pH 4.5, and total As was determined after a pre-reduction reaction with 1.0% (w/v) thiourea. Ultrasound-assisted acid extraction was performed, and the parameters sonication time and acid and Triton X-114 concentrations were optimized using a 23 factorial design and central composite design. LODs for As(lll) and total As were 0.029 and 0.022 microg/L, respectively. The accuracy of the method was confirmed with certified reference materials. The method was successfully applied in the determination of inorganic As in phosphate fertilizer samples.

  2. Quantifying uncertainty in the measurement of arsenic in suspended particulate matter by Atomic Absorption Spectrometry with hydride generator

    PubMed Central

    2011-01-01

    Arsenic is the toxic element, which creates several problems in human being specially when inhaled through air. So the accurate and precise measurement of arsenic in suspended particulate matter (SPM) is of prime importance as it gives information about the level of toxicity in the environment, and preventive measures could be taken in the effective areas. Quality assurance is equally important in the measurement of arsenic in SPM samples before making any decision. The quality and reliability of the data of such volatile elements depends upon the measurement of uncertainty of each step involved from sampling to analysis. The analytical results quantifying uncertainty gives a measure of the confidence level of the concerned laboratory. So the main objective of this study was to determine arsenic content in SPM samples with uncertainty budget and to find out various potential sources of uncertainty, which affects the results. Keeping these facts, we have selected seven diverse sites of Delhi (National Capital of India) for quantification of arsenic content in SPM samples with uncertainty budget following sampling by HVS to analysis by Atomic Absorption Spectrometer-Hydride Generator (AAS-HG). In the measurement of arsenic in SPM samples so many steps are involved from sampling to final result and we have considered various potential sources of uncertainties. The calculation of uncertainty is based on ISO/IEC17025: 2005 document and EURACHEM guideline. It has been found that the final results mostly depend on the uncertainty in measurement mainly due to repeatability, final volume prepared for analysis, weighing balance and sampling by HVS. After the analysis of data of seven diverse sites of Delhi, it has been concluded that during the period from 31st Jan. 2008 to 7th Feb. 2008 the arsenic concentration varies from 1.44 ± 0.25 to 5.58 ± 0.55 ng/m3 with 95% confidence level (k = 2). PMID:21466671

  3. Guidelines on CV networking information flow optimization for Texas.

    DOT National Transportation Integrated Search

    2017-03-01

    Recognizing the fundamental role of information flow in future transportation applications, the research team investigated the quality and security of information flow in the connected vehicle (CV) environment. The research team identified key challe...

  4. Exploration of polyamide structure-property relationships by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Barrère, Caroline; Rejaibi, Majed; Curat, Aurélien; Hubert-Roux, Marie; Lavanant, Hélène; Afonso, Carlos; Kebir, Nasreddine; Desilles, Nicolas; Lecamp, Laurence; Burel, Fabrice; Loutelier-Bourhis, Corinne

    2014-08-15

    Polyamides (PA) are among the most used classes of polymers because of their attractive properties. Depending on the nature and proportion of the co-monomers used for their synthesis, they can exhibit a very large range of melting temperatures (Tm ). This study aims at the correlation of data from mass spectrometry (MS) with differential scanning calorimetry (DSC) and X-ray diffraction analyses to relate molecular structure to physical properties such as melting temperature, enthalpy change and crystallinity rate. Six different PA copolymers with molecular weights around 3500 g mol(-1) were synthesized with varying proportions of different co-monomers (amino-acid AB/di-amine AA/di-acid BB). Their melting temperature, enthalpy change and crystallinity rate were measured by DSC and X-ray diffraction. Their structural characterization was carried out by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Because of the poor solubility of PA, a solvent-free sample preparation strategy was used with 2,5-dihydroxybenzoic acid (2,5-DHB) as the matrix and sodium iodide as the cationizing agent. The different proportions of the repeating unit types led to the formation of PA with melting temperatures ranging from 115°C to 185°C. The structural characterization of these samples by MALDI-TOF-MS revealed a collection of different ion distributions with different sequences of repeating units (AA, BB; AB/AA, BB and AB) in different proportions according to the mixture of monomers used in the synthesis. The relative intensities of these ion distributions were related to sample complexity and structure. They were correlated to DSC and X-ray results, to explain the observed physical properties. The structural information obtained by MALDI-TOF-MS provided a better understanding of the variation of the PA melting temperature and established a structure-properties relationship. This work will allow future PA designs to be monitored. Copyright

  5. Changes in UV absorption of sunscreens after UV irradiation

    NASA Astrophysics Data System (ADS)

    Tarras-Wahlberg, N.; Stenhagen, G.; Larkö, O.; Rosén, A.; Wennberg, A.-M.; Wennerström, O.

    2000-03-01

    In the present investigation we have studied the change in the absorption spectrum of some photoactive organic species in sunscreens after UVA and UVB irradiation in a dose normally encountered during a full day in the sun. The absorbance of 2-ethylhexyl 4-methoxycinnamate was reduced significantly, while 3-(4-methylbenzyliden)camphor seemed to be rather stable. The benzophenones studied seemed to be relatively stable. In the case of 4-tert.butyl-4´-methoxy-dibenzoylmethane there was a rapid decrease in the UVA absorption leading to unsatisfactory protection in the UVA region. 4-Isopropyl-dibenzoylmethane also lost most of its UV protective capacity after irradiation with UVA. UVB seemed to have a minor effect on all the samples. The present study including gas chromatography and mass spectrometry analysis indicates that some of the photoactive organic species commonly used today in sunscreens are unstable following UV irradiation.

  6. Is the presence of AA amyloidosis associated with impaired coronary flow reserve?

    PubMed

    Bulut, Mustafa; Keles, Nursen; Caliskan, Zuhal; Kostek, Osman; Aksu, Feyza; Ozdil, Kamil; Akcakoyun, Mustafa; Demircioglu, Kenan; Yilmaz, Yusuf; Kanbay, Mehmet; Caliskan, Mustafa

    2016-08-01

    Systemic amyloid A protein (AA) amyloidosis may occur as a complication of many chronic inflammatory disorders. Patients receiving inadequate anti-inflammatory and immunosuppressive therapies have an increased risk of developing systemic AA amyloidosis. Inflammation plays a role in all stages and the thrombotic complications of atherosclerosis. In the absence of epicardial coronary stenosis, coronary flow reserve (CFR) reflects coronary microvascular dysfunction. In the present study, we hypothesized that amyloid advanced subclinical inflammation in chronic inflammatory diseases (CID) patients may further affect coronary microcirculation. Thirty-two patients with biopsy-diagnosed renal AA, 73 patients with non-amyloid CID, and a group of healthy volunteers were included in the study. The measurements of coronary flow velocity were performed by a single investigator with expertise in transthoracic Doppler harmonic echocardiography (TTDE). The AA amyloidosis subgroup had significantly lower CFR values than other non-amyloid CID patients and the control individuals (1.8 (1.5-2.1) vs. 2.1 (2.0-2.4) and 3.0 (2.8-3.2), p < 0.001). Multivariate logistic regression analysis indicated that the presence of AA amyloidosis and elevated hs - CRP independently predict impairment of the CFR (p < 0.05). The presence of AA amyloidosis is related to decreased CFR values and the presence of AA amyloidosis and elevated hs - CRP independently predict impairment of the CFR. Therefore, patients with AA amyloidosis may have an increased risk of developing coronary artery diseases. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. PDGF-AA-induced filamentous mitochondria benefit dermal papilla cells in cellular migration.

    PubMed

    Mifude, C; Kaseda, K

    2015-06-01

    Human dermal papilla cells (HDPCs) play essential roles in hair follicular morphogenesis and postnatal hair growth cycles. Previous reports demonstrated that platelet-derived growth factor-AA (PDGF-AA) enhanced the formation of dermal condensates in hair follicular development. Additionally, PDGF-AA induces/maintains the anagen phase of the hair cycle. It is likely that mitochondrial morphology and functions are tightly coupled with maintenance of these energy-demanding activities. However, little is known about the mitochondrial regulation in HDPCs. Thus, we investigated the PDGF-involved mitochondrial regulation in HDPCs. The mitochondrial morphologies of HDPCs were examined in the presence or absence of PDGF-AA under a fluorescent microscope. ATP production and cellular motility were investigated. The relationship between mitochondrial morphology and the cellular functions was discussed. We observed that primary HDPCs contained mitochondria with filamentous and/or rounded morphologies. Both types of mitochondria showed similar membrane potentials. Interestingly, in the presence of PDGF-AA, but not PDGF-BB, the balance between the two morphologies shifted towards the filamentous form. Concomitantly, both mitochondrial enzymatic activity and total cellular ATP level were augmented by PDGF-AA. These two parameters were closely correlated, suggesting the mitochondrial involvement in the PDGF-augmented ATP production. Moreover, PDGF-AA accelerated the migration of HDPCs in a gap-filling assay, but did not change the rate of cellular proliferation. Notably, filamentous mitochondria dominated migrating HDPCs. PDGF-AA benefits HDPCs in the process of migration, by increasing the number of filamentous mitochondria. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  8. Gas chromatography/chemical ionization triple quadrupole mass spectrometry analysis of anabolic steroids: ionization and collision-induced dissociation behavior.

    PubMed

    Polet, Michael; Van Gansbeke, Wim; Van Eenoo, Peter; Deventer, Koen

    2016-02-28

    The detection of new anabolic steroid metabolites and new designer steroids is a challenging task in doping analysis. Switching from electron ionization gas chromatography triple quadrupole mass spectrometry (GC/EI-MS/MS) to chemical ionization (CI) has proven to be an efficient way to increase the sensitivity of GC/MS/MS analyses and facilitate the detection of anabolic steroids. CI also extends the possibilities of GC/MS/MS analyses as the molecular ion is retained in its protonated form due to the softer ionization. In EI it can be difficult to find previously unknown but expected metabolites due to the low abundance or absence of the molecular ion and the extensive (and to a large extent unpredictable) fragmentation. The main aim of this work was to study the CI and collision-induced dissociation (CID) behavior of a large number of anabolic androgenic steroids (AAS) as their trimethylsilyl derivatives in order to determine correlations between structures and CID fragmentation. Clarification of these correlations is needed for the elucidation of structures of unknown steroids and new metabolites. The ionization and CID behavior of 65 AAS have been studied using GC/CI-MS/MS with ammonia as the reagent gas. Glucuronidated AAS reference standards were first hydrolyzed to obtain their free forms. Afterwards, all the standards were derivatized to their trimethylsilyl forms. Full scan and product ion scan analyses were used to examine the ionization and CID behavior. Full scan and product ion scan analyses revealed clear correlations between AAS structure and the obtained mass spectra. These correlations were confirmed by analysis of multiple hydroxylated, methylated, chlorinated and deuterated analogs. AAS have been divided into three groups according to their ionization behavior and into seven groups according to their CID behavior. Correlations between fragmentation and structure were revealed and fragmentation pathways were postulated. Copyright © 2016 John Wiley

  9. D-Glucosone and L-sorbosone, putative intermediates of L-ascorbic acid biosynthesis in detached bean and spinach leaves. [Phaseolus vulgaris L. ; Spinacia oleracea L

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saito, Kazumi; Nick, J.A.; Loewus, F.A.

    D-(6-{sup 14}C)Glucosone that had been prepared enzymically from D-(6-{sup 14}C)glucose was used to compare relative efficiencies of these two sugars for L-ascorbic acid (AA) biosynthesis in detached bean (Phaseolus vulgaris L., cv California small white) apices and 4-week-old spinach (Spinacia oleracea L., cv Giant Noble) leaves. At tracer concentration, {sup 14}C from glucosone was utilized by spinach leaves for AA biosynthesis much more effectively than glucose. Carbon-14 from (6-{sup 14}C)glucose underwent considerable redistribution during AA formation, whereas {sup 14}C from (6-{sup 14}C)glucosone remained almost totally in carbon 6 of AA. In other experiments with spinach leaves, L-(U-{sup 14}C)sorbosone was foundmore » to be equivalent to (6-{sup 14}C)glucose as a source of {sup 14}C for AA. In the presence of 0.1% D-glucosone, conversion of (6-{sup 14}C) glucose into labeled AA was greatly repressed. In a comparable experiment with L-sorbosone replacing D-glucosone, the effect was much less. The experiments described here give substance to the proposal that D-glucosone and L-sorbosone are putative intermediates in the conversion of D-glucose to AA in higher plants.« less

  10. Percutaneous absorption of aromatic amines in rubber industry workers: impact of impaired skin and skin barrier creams

    PubMed Central

    Korinth, G; Weiss, T; Penkert, S; Schaller, K H; Angerer, J; Drexler, H

    2007-01-01

    Background Several aromatic amines (AA) could cause bladder cancer and are an occupational hygiene problem in the workplace. However, little is known about the percutaneous absorption of chemicals via impaired skin and about the efficacy of skin protection measures to reduce internal exposure. Aims To determine the impact of skin status and of skin protection measures on the internal exposure to AA in workers manufacturing rubber products. Methods 51 workers occupationally exposed to aniline and o‐toluidine were examined. The workplace conditions, risk factors for skin and the use of personal protective equipment were assessed by means of a self‐administered questionnaire. The skin of hands and forearms was clinically examined. Exposure to aniline and o‐toluidine was assessed by ambient air and biological monitoring (analyses of urine samples and of haemoglobin adducts). Results Haemoglobin‐AA‐adduct levels in workers with erythema (73%) were significantly higher (p<0.04) than in workers with healthy skin (mean values: aniline 1150.4 ng/l vs 951.7 ng/l, o‐toluidine 417.9 ng/l vs 118.3 ng/l). The multiple linear regression analysis showed that wearing gloves significantly reduced the internal exposure. A frequent use of skin barrier creams leads to a higher internal exposure of AA (p<0.03). However, the use of skincare creams at the workplace was associated with a reduced internal exposure (p<0.03). From these findings we assume that internal exposure of the workers resulted primarily from the percutaneous uptake. Conclusions The study demonstrates a significantly higher internal exposure to AA in workers with impaired skin compared with workers with healthy skin. Daily wearing of gloves efficiently reduced internal exposure. However, an increased use of skin barrier creams enhances the percutaneous uptake of AA. Skincare creams seem to support skin regeneration and lead to reduced percutaneous uptake. PMID:17182646

  11. Classification of type 2 diabetes rats based on urine amino acids metabolic profiling by liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Wang, Chunyan; Zhu, Hongbin; Pi, Zifeng; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

    2013-09-15

    An analytical method for quantifying underivatized amino acids (AAs) in urine samples of rats was developed by using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Classification of type 2 diabetes rats was based on urine amino acids metabolic profiling. LC-MS/MS analysis was applied through chromatographic separation and multiple reactions monitoring (MRM) transitions of MS/MS. Multivariate profile-wide predictive models were constructed using partial least squares discriminant analysis (PLS-DA) by SIMAC-P 11.5 version software package and hierarchical cluster analysis (HCA) by SPSS 18.0 version software. Some amino acids in urine of rats have significant change. The results of the present study prove that this method could perform the quantification of free AAs in urine of rats by using LC-MS/MS. In summary, the PLS-DA and HCA statistical analysis in our research were preferable to differentiate healthy rats and type 2 diabetes rats by the quantification of AAs in their urine samples. In addition, comparing with health group the seven increased amino acids in urine of type 2 rats were returned to normal under the treatment of acarbose. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. [A review for recent advances in AA amyloid research and therapeutic approach to AA amyloidosis complicating rheumatoid arthritis].

    PubMed

    Tamura, Hiroaki; Hasegawa, Kiminori

    2009-02-01

    AA amyloidosis is a life threatening clinical complication of chronic inflammatory diseases such as rheumatoid arthritis. It has been demonstrated biochemically that amyloidosis resulted from abnormal folding of proteins, which are deposited as insoluble fibrils in extracellular tissue, leading to the disruption of their normal function. In this regard, amyloidosis has been recognized as a conformation disorder. Interestingly, genetic polymorphisms of amyloid precursor protein (SAA) have been reported to associate with increased risk for AA amyloidosis. Also recent biochemical research revealed that SAA is synthesized under the influence of the proinflammatory cytokines, such as IL-6, TNF-alpha, IL-1. Additionally, it was suggested that amyloid deposits in extracellular tissue could reflect to the serum level of SAA in the reversible fashion, leading to the hypothesis that the control of the SAA synthesis could be beneficial to the treatment of amyloidosis. In this context, anti-cytokine therapies may be most effective. Especially the inhibition of IL-6 is critical to suppression of SAA production, so treatment with a humanized monoclonal antibody against human IL-6 receptor may not only ameliorate RA disease activity but also pave the way for the treatment of AA amyloidosis.

  13. Chemical composition and α-amylase inhibitory activity of the essential oil from Sabina chinensis cv. Kaizuca leaves.

    PubMed

    Gu, Dongyu; Fang, Chen; Yang, Jiao; Li, Minjing; Liu, Hengming; Yang, Yi

    2018-03-01

    Sabina chinensis cv. Kaizuca (SCK) is a variant of S. chinensis L. The essential oil from its leaves exhibited α-amylase inhibitory activity in vitro and the IC 50 value was 187.08 ± 0.56 μg/mL. Nineteen compounds were identified from this essential oil by gas chromatography-mass spectrometry (GC-MS) analysis. The major compounds identified were bornyl acetate (42.6%), elemol (20.5%), β-myrcene (13.7%) and β-linalool (4.0%). In order to study the reason of the α-amylase inhibitory activity of this essential oil, the identified compounds were docked with α-amylase by molecular docking individually. Among these compounds, γ-eudesmol exhibited the lowest binding energy (-6.73 kcal/mol), followed by α-copaen-11-ol (-6.66 kcal/mol), cubedol (-6.39 kcal/mol) and α-acorenol (-6.12 kcal/mol). The results indicated that these compounds were the active ingredients responsible for the α-amylase inhibitory activity of essential oil from SCK.

  14. Automated solid-phase extraction-liquid chromatography-tandem mass spectrometry analysis of 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in human urine specimens: application to a high-throughput urine analysis laboratory.

    PubMed

    Robandt, P V; Klette, K L; Sibum, M

    2009-10-01

    An automated solid-phase extraction coupled with liquid chromatography and tandem mass spectrometry (SPE-LC-MS-MS) method for the analysis of 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in human urine specimens was developed. The method was linear (R(2) = 0.9986) to 1000 ng/mL with no carryover evidenced at 2000 ng/mL. Limits of quantification and detection were found to be 2 ng/mL. Interrun precision was evaluated at the 15 ng/mL level over nine batches spanning 15 days (n = 45). The coefficient of variation (%CV) was found to be 5.5% over the course of the validation. Intrarun precision of a 15 ng/mL control (n = 5) ranged from 0.58% CV to 7.4% CV for the same set of analytical batches. Interference was tested using (+/-)-11-hydroxy-Delta(9)-tetrahydrocannabinol, cannabidiol, (-)-Delta(8)-tetrahydrocannabinol, and cannabinol. One hundred and nineteen specimens previously found to contain THC-COOH by a previously validated gas chromatographic mass spectrometry (GC-MS) procedure were compared to the SPE-LC-MS-MS method. Excellent agreement was found (R(2) = 0.9925) for the parallel comparison study. The automated SPE procedure eliminates the human factors of specimen handling, extraction, and derivatization, thereby reducing labor costs and rework resulting from human error or technique issues. Additionally, method runtime is greatly reduced (e.g., during parallel studies the SPE-LC-MS-MS instrument was often finished with analysis by the time the technician finished the offline SPE and derivatization procedure prior to the GC-MS analysis).

  15. Overcoming Matrix Effects in a Complex Sample: Analysis of Multiple Elements in Multivitamins by Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Arnold, Randy J.; Arndt, Brett; Blaser, Emilia; Blosser, Chris; Caulton, Dana; Chung, Won Sog; Fiorenza, Garrett; Heath, Wyatt; Jacobs, Alex; Kahng, Eunice; Koh, Eun; Le, Thao; Mandla, Kyle; McCory, Chelsey; Newman, Laura; Pithadia, Amit; Reckelhoff, Anna; Rheinhardt, Joseph; Skljarevski, Sonja; Stuart, Jordyn; Taylor, Cassie; Thomas, Scott; Tse, Kyle; Wall, Rachel; Warkentien, Chad

    2011-01-01

    A multivitamin tablet and liquid are analyzed for the elements calcium, magnesium, iron, zinc, copper, and manganese using atomic absorption spectrometry. Linear calibration and standard addition are used for all elements except calcium, allowing for an estimate of the matrix effects encountered for this complex sample. Sample preparation using…

  16. Copper-65-absorption by men fed intrinsically and extrinsically labeled whole wheat bread

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Johnson, P.E.; Lykken, G.I.

    Six men were fed a diet composed of conventional foods with all bread as whole wheat bread. Intrinsically labeled /sup 65/Cu bread (containing 6.5 ppm Cu and 48 atom % /sup 65/Cu) was substituted for unlabeled bread for 3 days, and stools were collected for 24 days. Extrinsically labeled bread was then substituted for 3 days and another 24-day stool collection made. /sup 65/Cu excretion was measured by mass spectrometry. Mean Cu intake was 1.10 mg of Cu/day. Average Cu balance was /minus/0.06 /+-/ 0.08 mg/day. Average absorption of the intrinsic copper was 72.2 /+-/ 9.3% and of extrinsic Cumore » 64.2 /+-/ 5.8%. The ratio of extrinsic to intrinsic absorption was 0.906 /+-/ 0.164. Absorption of intrinsic and extrinsic tracers did not differ significantly (p > 0.05) by a paired t-test, and the ratio (E/I) was not significantly different from 1. Use of extrinsic Cu tracers to assess Cu absorption is supported by these results.« less

  17. Identification of AaCASPS7, an effector caspase in Aedes albopictus.

    PubMed

    Feng, Lingyan; Liu, Hao; Li, Xiaomei; Qiao, Jialu; Wang, Shengya; Guo, Deyin; Liu, Qingzhen

    2016-11-15

    Aedes albopictus mosquito is a vector of various arboviruses and is becoming a significant threat to public health due to its rapid global expansion. Several reports suggest that apoptosis could be a factor limiting arbovirus infection in mosquitoes. Thus, it is significant to identify apoptosis pathway and study the correlation between apoptosis and virus infection in mosquitoes. Apoptosis is a type of programmed cell death that plays a vital role in immunity, development, and tissue homeostasis. Caspases are a family of conserved proteases playing important roles in apoptosis. In this study, we identified Aedes albopictus AaCASPS7, a caspase shared high identity with dipteran insect drICE orthologs. Phylogenetic analysis showed the closest relative of AaCASPS7 was Aedes aegypti AeCASPS7. AaCASPS7 displayed several features that were typical of an effector caspase and showed significant activity to effector caspase substrates. Aacasps7 transcripts were expressed ubiquitously in developmental and adult stages in Aedes albopictus mosquitoes. Transient expression of AaCASPS7 induced caspase-dependent apoptosis in C6/36 cells. Taken together the above data, this study identified a novel caspase, AaCASPS7, which might function as an apoptotic caspase. Further study the function of AaCASPS7 would facilitate better understanding the apoptotic mechanism in Aedes albopictus mosquito. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Isotopic coherence of refractory inclusions from CV and CK meteorites: Evidence from multiple isotope systems

    NASA Astrophysics Data System (ADS)

    Shollenberger, Quinn R.; Borg, Lars E.; Render, Jan; Ebert, Samuel; Bischoff, Addi; Russell, Sara S.; Brennecka, Gregory A.

    2018-05-01

    Calcium-aluminum-rich inclusions (CAIs) are the oldest dated materials in the Solar System and numerous previous studies have revealed nucleosynthetic anomalies relative to terrestrial rock standards in many isotopic systems. However, most of the isotopic data from CAIs has been limited to the Allende meteorite and a handful of other CV3 chondrites. To better constrain the isotopic composition of the CAI-forming region, we report the first Sr, Mo, Ba, Nd, and Sm isotopic compositions of two CAIs hosted in the CK3 desert meteorites NWA 4964 and NWA 6254 along with two CAIs from the CV3 desert meteorites NWA 6619 and NWA 6991. After consideration of neutron capture processes and the effects of hot-desert weathering, the Sr, Mo, Ba, Nd, and Sm stable isotopic compositions of the samples show clearly resolvable nucleosynthetic anomalies that are in agreement with previous results from Allende and other CV meteorites. The extent of neutron capture, as manifested by shifts in the observed 149Sm-150Sm isotopic composition of the CAIs is used to estimate the neutron fluence experienced by some of these samples and ranges from 8.40 × 1013 to 2.11 × 1015 n/cm2. Overall, regardless of CAI type or host meteorite, CAIs from CV and CK chondrites have similar nucleosynthetic anomalies within analytical uncertainty. We suggest the region that CV and CK CAIs formed was largely uniform with respect to Sr, Mo, Ba, Nd, and Sm isotopes when CAIs condensed and that CAIs hosted in CV and CK meteorites are derived from the same isotopic reservoir.

  19. [Determination of heavy metals for RoHS compliance by ICP-OES spectrometry coupled with microwave extraction system].

    PubMed

    Hua, Li; Wu, Yi-Ping; An, Bing; Lai, Xiao-Wei

    2008-11-01

    The harm of heavy metals contained in electronic and electrical equipment (EEE) on environment is of high concern by human. Aiming to handle the great challenge of RoHS compliance, the determinations of trace or ultratrace chromium (Cr), cadmium (Cd), mercury (Hg) and lead (Pb) by inductively coupled plasma optical emission spectrometry (ICP-OES) was performed in the present paper, wherein, microwave extraction technology was used to prepare the sample solutions. In addition, the precision, recovery, repeatability and interference issues of this method were also discussed. The results exhibited that using the microwave extraction system to prepare samples is more quick, lossless, contamination-free in comparison with the conventional extraction methods such as dry ashing, wet-oven extraction etc. By analyzing the recoveries of these four heavy metals over different working time and wavelengths, the good recovery range between 85% and 115% showed that there was only tiny loss or contamination during the process of microwave extraction, sample introduction and ICP detection. Repeatability experiments proved that ICP plasma had a good stability during the working time and the matrix effect was small. Interference was a problem troublesome for atomic absorption spectrometry (AAS), however, the techniques of standard additions or inter-element correction (IEC) method can effectively eliminated the interferences of Ni, As, Fe etc. with the Cd determination. By employing the multi-wavelengths and two correction point methods, the issues of background curve sloping shift and spectra overlap were successfully overcome. Besides, for the determinations of trace heavy metal elements, the relative standard deviation (RSD) was less than 3% and the detection limits were less than 1 microg x L(-10 (3sigma, n = 5) for samples, standard solutions, and standard additions, which proved that ICP-OES has a good precision and high reliability. This provided a reliable technique support

  20. Plant response to lead in the presence or absence EDTA in two sunflower genotypes (cultivated H. annuus cv. 1114 and interspecific line H. annuus × H. argophyllus).

    PubMed

    Doncheva, Snezhana; Moustakas, Michael; Ananieva, Kalina; Chavdarova, Martina; Gesheva, Emiliya; Vassilevska, Rumyana; Mateev, Plamen

    2013-02-01

    The aim of the present work was to study the response of two sunflower genotypes (cultivated sunflower Helianthus annuus cv. 1114 and newly developed genotype H. annuus × Helianthus argophyllus) to Pb medium-term stress and the role of exogenously applied EDTA in alleviating Pb toxicity in hydroponics. Plant growth, morpho-anatomical characteristics of the leaf tissues, electrolyte leakage, total antioxidant activity, free radical scavenging capacity, total flavonoid content, and superoxide dismutase isoenzyme profile were studied by conventional methods. Differential responses of both genotypes to Pb supplied in the nutrient solution were recorded. Pb treatment induced a decrease in the relative growth rate, disturbance of plasma membrane integrity, and changes in the morpho-anatomical characteristics of the leaf tissues and in the antioxidant capacity, which were more pronounced in the cultivated sunflower H. annuus cv. 1114. The new genotype demonstrated higher tolerance to Pb when compared with the cultivar. This was mainly due to increased photosynthetically active area, maintenance of plasma membrane integrity, permanently high total antioxidant activity, and free radical scavenging capacity as well as total flavonoid content. The addition of EDTA into the nutrient solution led to limitation of the negative impact of Pb ions on the above parameters in both genotypes. This could be related to the reduced content of Pb in the roots, stems, and leaves, suggesting that the presence of EDTA limited the uptake of Pb. The comparative analysis of the responses to Pb treatment showed that the deleterious effect of Pb was more pronounced in the cultivated sunflower H. annuus cv. 1114. The new genotype H. annuus × H. argophyllus was more productive and demonstrated higher tolerance to Pb medium-term stress, which could indicate that it may possess certain mechanisms to tolerate high Pb concentrations. This character could be inherited from the wild parent used in the

  1. AA Attendance and Abstinence for Dually Diagnosed Patients: A Meta-Analytic Review.

    PubMed

    Scott Tonigan, J; Pearson, Matthew R; Magill, Molly; Hagler, Kylee J

    2018-05-29

    There is consensus that best clinical practice for dual diagnosis (DD) is integrated mental health and substance use treatment augmented with Alcoholics Anonymous (AA) attendance. This is the first quantitative review of the direction and magnitude of the association between AA attendance and alcohol abstinence for DD patients. A systematic literature search (1993-2017) identified 22 studies yielding 24 effect sizes that met our inclusion criteria (8,075 patients). Inverse-variance weighting of correlation coefficients (r) was used to aggregate sample-level findings and study aims were addressed using random and mixed effect models. Sensitivity and publication bias analyses were conducted to assess the likelihood of bias in the overall estimate of AA-related benefit. AA exposure and abstinence for DD patients were significantly and positively associated (r w =.249; 95% CI.203-.293; Tau=.097). There was also significant heterogeneity in the distribution of effect sizes, (Q(23)=90.714, p<.001), and high between-sample variance (I 2 =74.646). Subgroup analyses indicated that the magnitude of AA-related benefit did not differ between 6 (k=7) and 12 (k=12) month follow-up, (Q=.068, p<.794), type of treatment received (inpatient k=9; intensive outpatient, outpatient, community k=15; Q=2.057, p<.152), and whether a majority of patients in a sample had (k=11) or did not have (k=13) major depression (Q=.563, p<.453). Sensitivity analyses indicated that the overall meta-analytic estimate of AA benefit was not adversely or substantively impacted by pooling RCT and observational samples (Q=.763, p<.382), pooling count, binary, and ordinal-based AA (Q=.023, p<.879) and outcome data (Q=1.906, p<.167), and reversing direction of correlations extracted from studies (Q=.006, p<.937). No support was found for publication bias. Clinical referral of dual diagnosis (DD) patients to Alcoholics Anonymous (AA) is common and, in many cases, DD patients who attend AA will report higher

  2. A simple heat-pipe cell for X-ray absorption spectrometry of potassium vapor

    NASA Astrophysics Data System (ADS)

    Pres̆eren, R.; Kodre, A.; Arc̆on, I.; Padez̆nik Gomils̆ek, J.; Hribar, M.

    1999-01-01

    The construction and operation of a simple high-temperature X-ray absorption cell for potassium vapor is described. The principle of "spectroscopic heat pipe" is exploited to separate kapton windows, indispensable for good transmission in the low-energy region, from the hot and aggressive vapor. High-resolution spectrum of the K-edge region of atomic potassium reveals fingerprints of multielectron photoexcitations.

  3. Green Preconcentration of Trace Amounts of Copper from Water and Food Samples onto Novel Organo-Nanoclay Prior to Flame Atomic Absorption Spectrometry.

    PubMed

    Beyki, Mostafa Hossein; Shemirani, Farzaneh; Khani, Rouhollah

    2014-01-01

    In this work, the nanoclay was intercalated with acyclovir (9-[(2-hydroxyethoxy) methyl] guanine), the toxicity of which to mammalian cells is very low. We used no organic solvents for preparation of modified clay and desorption of Cu ions from the sorbent. Batch and column methods were used, and sorption of Cu was quantitative (>98%) in the pH range of 7.5 to 10.0. Quantitative desorption occurred with 5.0 mL of 3.0 M HCl, and the amount of Cu(II) was measured by using flame atomic absorption spectrometry. In the initial solution the linear dynamic range and the LOD were 3.0-1000.0 and 0.58 μg/L, respectively. With 500.0 mL of sample, an enrichment factor of 100 was obtained. The RSD was 2.0% (n = 8, concentration = 0.5 mg/L), and the maximum capacity of the sorbent was 45.0 mg/g. The influence of experimental parameters including sample pH, ionic strength, type and volume of the eluent, and interference of some ions on the recoveries of Cu was investigated. The proposed method using a new and easier prepared solid sorbent was applied to the determination of Cu in different real samples with satisfactory results.

  4. Molecular Differences in Hepatic Metabolism between AA Broiler and Big Bone Chickens: A Proteomic Study.

    PubMed

    Zheng, Aijuan; Chang, Wenhuan; Liu, Guohua; Yue, Ying; Li, Jianke; Zhang, Shu; Cai, Huiyi; Yang, Aijun; Chen, Zhimin

    2016-01-01

    Identifying the metabolic differences in the livers of modern broilers and local chicken breeds is important for understanding their biological characteristics, and many proteomic changes in their livers are not well characterized. We therefore analyzed the hepatic protein profiles of a commercial breed, Arbor Acres (AA) broilers, and a local dual purpose breed, Big Bone chickens, using two-dimensional electrophoresis combined with liquid chromatography-chip/electrospray ionization-quadruple time-of-flight/mass spectrometry (LC-MS/MS). A total of 145 proteins were identified as having differential abundance in the two breeds at three growth stages. Among them, 49, 63 and 54 belonged to 2, 4, and 6 weeks of age, respectively. The higher abundance proteins in AA broilers were related to the energy production pathways suggesting enhanced energy metabolism and lipid biosynthesis. In contrast, the higher abundance proteins in Big Bone chickens showed enhanced lipid degradation, resulting in a reduction in the abdominal fat percentage. Along with the decrease in fat deposition, flavor substance synthesis in the meat of the Big Bone chickens may be improved by enhanced abundance of proteins involved in glycine metabolism. In addition, the identified proteins in nucleotide metabolism, antioxidants, cell structure, protein folding and transporters may be critically important for immune defense, gene transcription and other biological processes in the two breeds. These results indicate that selection pressure may have shaped the two lines differently resulting in different hepatic metabolic capacities and extensive metabolic differences in the liver. The results from this study may help provide the theoretical basis for chicken breeding.

  5. Systemic AA amyloidosis in the red fox (Vulpes vulpes).

    PubMed

    Rising, Anna; Cederlund, Ella; Palmberg, Carina; Uhlhorn, Henrik; Gaunitz, Stefan; Nordling, Kerstin; Ågren, Erik; Ihse, Elisabet; Westermark, Gunilla T; Tjernberg, Lars; Jörnvall, Hans; Johansson, Jan; Westermark, Per

    2017-11-01

    Amyloid A (AA) amyloidosis occurs spontaneously in many mammals and birds, but the prevalence varies considerably among different species, and even among subgroups of the same species. The Blue fox and the Gray fox seem to be resistant to the development of AA amyloidosis, while Island foxes have a high prevalence of the disease. Herein, we report on the identification of AA amyloidosis in the Red fox (Vulpes vulpes). Edman degradation and tandem MS analysis of proteolyzed amyloid protein revealed that the amyloid partly was composed of full-length SAA. Its amino acid sequence was determined and found to consist of 111 amino acid residues. Based on inter-species sequence comparisons we found four residue exchanges (Ser31, Lys63, Leu71, Lys72) between the Red and Blue fox SAAs. Lys63 seems unique to the Red fox SAA. We found no obvious explanation to how these exchanges might correlate with the reported differences in SAA amyloidogenicity. Furthermore, in contrast to fibrils from many other mammalian species, the isolated amyloid fibrils from Red fox did not seed AA amyloidosis in a mouse model. © 2017 The Protein Society.

  6. Dispersive liquid-liquid microextraction based on solidification of floating organic drop for preconcentration and determination of trace amounts of copper by flame atomic absorption spectrometry.

    PubMed

    Karadaş, Cennet; Kara, Derya

    2017-04-01

    A novel, simple, rapid, sensitive, inexpensive and environmentally friendly dispersive liquid-liquid microextraction method based on the solidification of a floating organic drop (DLLME-SFO) was developed for the determination of copper by flame atomic absorption spectrometry (FAAS). N-o-Vanillidine-2-amino-p-cresol was used as a chelating ligand and 1-undecanol was selected as an extraction solvent. The main parameters affecting the performance of DLLME-SFO, such as sample pH, volume of extraction solvent, extraction time, concentration of the chelating ligand, salt effect, centrifugation time and sample volume were investigated and optimized. The effect of interfering ions on the recovery of copper was also examined. Under the optimum conditions, the detection limit (3σ) was 0.93μgL -1 for Cu using a sample volume of 20mL, yielding a preconcentration factor of 20. The proposed method was successfully applied to the determination of Cu in tap, river and seawater, rice flour and black tea samples as well as certified reference materials. Copyright © 2016. Published by Elsevier Ltd.

  7. Separation/preconcentration and determination of vanadium with dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) and electrothermal atomic absorption spectrometry.

    PubMed

    Asadollahi, Tahereh; Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji

    2010-06-30

    A novel dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) for separation/preconcentration of ultra trace amount of vanadium and its determination with the electrothermal atomic absorption spectrometry (ETAAS) was developed. The DLLME-SFO behavior of vanadium (V) using N-benzoyl-N-phenylhydroxylamine (BPHA) as complexing agent was systematically investigated. The factors influencing the complex formation and extraction by DLLME-SFO method were optimized. Under the optimized conditions: 100 microL, 200 microL and 25 mL of extraction solvent (1-undecanol), disperser solvent (acetone) and sample volume, respectively, an enrichment factor of 184, a detection limit (based on 3S(b)/m) of 7 ng L(-1) and a relative standard deviation of 4.6% (at 500 ng L(-1)) were obtained. The calibration graph using the preconcentration system for vanadium was linear from 20 to 1000 ng L(-1) with a correlation coefficient of 0.9996. The method was successfully applied for the determination of vanadium in water and parsley. Copyright 2010 Elsevier B.V. All rights reserved.

  8. Changes in depression mediate the effects of AA attendance on alcohol use outcomes.

    PubMed

    Wilcox, Claire E; Tonigan, J Scott

    2018-01-01

    Depression may contribute to increased drinking in individuals with alcohol use disorder. Although Alcoholics Anonymous (AA) attendance predicts drinking reductions, there is conflicting information regarding the intermediary role played by reductions in depression. We explored whether AA attendance reduces depressive symptoms, the degree to which improvement in depression results in reductions in drinking, and in which subgroups these effects occur. 253 early AA affiliates (63% male) were recruited and assessed at baseline 3, 6, 9, 12, 18, and 24 months. Depression was measured using the Beck Depression Inventory (BDI) and was administered at baseline 3, 6, 12, 18, and 24 months. AA attendance and alcohol use outcomes were obtained with the Form 90. Mediation analyses were performed at early (3, 6, and 9 months) and late (12, 18, and 24 months) follow-up to investigate the degree to which reductions in depression mediated the effect of AA attendance on drinking, controlling for concurrent drinking. In addition, a series of moderated mediation analyses were performed using baseline depression severity as a moderator. At early follow-up, reductions in depression (6 months) mediated the effects of AA attendance (3 months) on later drinking (drinks per drinking day) (9 months) (b = -0.02, boot CI [-0.055, -0.0004]), controlling for drinking at 6 months. Baseline depression severity did not moderate the degree to which BDI mediated the effects of AA attendance on alcohol use (ps > .05). These findings provide further evidence that depression reduction is a mechanism by which AA attendance leads to reductions in alcohol use. Improving depression may help reduce alcohol use in individuals with AUD, and AA attendance may be an effective way to achieve that goal.

  9. PALOMA:A Magnetic CV between Polars and Intermediate Polars

    NASA Astrophysics Data System (ADS)

    Joshi, Arti; Pandey, J. C.

    Using observations made with XMM-Newton, we present temporal and spectral analysis of an intermediate polar-like object Paloma. We also interpreted Paloma as a key object for magnetic CV evolution with an orbital period right within the period gap.

  10. Overexpression of AaWRKY1 Leads to an Enhanced Content of Artemisinin in Artemisia annua.

    PubMed

    Jiang, Weimin; Fu, Xueqing; Pan, Qifang; Tang, Yueli; Shen, Qian; Lv, Zongyou; Yan, Tingxiang; Shi, Pu; Li, Ling; Zhang, Lida; Wang, Guofeng; Sun, Xiaofen; Tang, Kexuan

    2016-01-01

    Artemisinin is an effective component of drugs against malaria. The regulation of artemisinin biosynthesis is at the forefront of artemisinin research. Previous studies showed that AaWRKY1 can regulate the expression of ADS, which is the first key enzyme in artemisinin biosynthetic pathway. In this study, AaWRKY1 was cloned, and it activated ADSpro and CYPpro in tobacco using dual-LUC assay. To further study the function of AaWRKY1, pCAMBIA2300-AaWRKY1 construct under 35S promoter was generated. Transgenic plants containing AaWRKY1 were obtained, and four independent lines with high expression of AaWRKY1 were analyzed. The expression of ADS and CYP, the key enzymes in artemisinin biosynthetic pathway, was dramatically increased in AaWRKY1-overexpressing A. annua plants. Furthermore, the artemisinin yield increased significantly in AaWRKY1-overexpressing A. annua plants. These results showed that AaWRKY1 increased the content of artemisinin by regulating the expression of both ADS and CYP. It provides a new insight into the mechanism of regulation on artemisinin biosynthesis via transcription factors in the future.

  11. Development of a simple method for the determination of lead in lipstick using alkaline solubilization and graphite furnace atomic absorption spectrometry.

    PubMed

    Soares, Aline Rodrigues; Nascentes, Clésia Cristina

    2013-02-15

    A simple method was developed for determining the total lead content in lipstick samples by graphite furnace atomic absorption spectrometry (GFAAS) after treatment with tetramethylammonium hydroxide (TMAH). Multivariate optimization was used to establish the optimal conditions of sample preparation. The graphite furnace heating program was optimized through pyrolysis and atomization curves. An aliquot containing approximately 50mg of the sample was mixed with TMAH and heated in a water bath at 60°C for 60 min. Using Nb as the permanent modifier and Pd as the chemical modifier, the optimal temperatures were 900°C and 1800°C for pyrolysis and atomization, respectively. Under optimum conditions, the working range was from 1.73 to 50.0 μg L(-1), with detection and quantification limits of 0.20 and 0.34 μg g(-1), respectively. The precision was evaluated under conditions of repeatability and intermediate precision and showed standard deviations of 2.37%-4.61% and 4.93%-9.75%, respectively. The % recovery ranged from 96.2% to 109%, and no significant differences were found between the results obtained using the proposed method and the microwave decomposition method for real samples. Lead was detected in 21 tested lipstick samples; the lead content in these samples ranged from 0.27 to 4.54 μg g(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Analysis and modeling of wafer-level process variability in 28 nm FD-SOI using split C-V measurements

    NASA Astrophysics Data System (ADS)

    Pradeep, Krishna; Poiroux, Thierry; Scheer, Patrick; Juge, André; Gouget, Gilles; Ghibaudo, Gérard

    2018-07-01

    This work details the analysis of wafer level global process variability in 28 nm FD-SOI using split C-V measurements. The proposed approach initially evaluates the native on wafer process variability using efficient extraction methods on split C-V measurements. The on-wafer threshold voltage (VT) variability is first studied and modeled using a simple analytical model. Then, a statistical model based on the Leti-UTSOI compact model is proposed to describe the total C-V variability in different bias conditions. This statistical model is finally used to study the contribution of each process parameter to the total C-V variability.

  13. The Effectiveness of the AAS REU Program

    NASA Astrophysics Data System (ADS)

    Hemenway, M. K.; Boyce, P. B.; Milkey, R. W.

    1996-05-01

    In an attempt to address the particular needs of astronomy faculty and undergraduate students, in 1991 the Education Office of the American Astronomical Society approached the National Science Foundation with a unique proposal for funding through the Research Experiences for Undergraduates program. The goals of the AAS program were to "slow the hemorrhage of students out of science...", extend the REU program to non-NSF-funded scientists, to reach under-represented women and minority students particularly in small educational institutions, and to encourage research scientists there to mentor students. As this grant has now expired, the AAS has surveyed the 44 mentors and their students to assess the program's effect on the mentor and the mentor's career; the educational institution; and the student's education and career choices. More than half the mentors responded by the abstract deadline. The program clearly had an effect upon the individuals involved. The greatest effect (in 85% of the cases) was to develop more interest in the mentor's research project both among the students and among the mentor's faculty colleagues. The mentors rated the grant to be a medium or strong factor in their student's decision to pursue graduate study, which 90% of them did. All but one of the AAS-REU students attended an AAS meeting and 3/4 of those gave a paper on their project research. Over 90% of the mentors felt that the research experience strongly promoted a greater interest in science, a greater understanding of science and a desire to continue in science. According to the mentors, this was a very positive and beneficial program for the students as well as for themselves.

  14. Tellurium speciation analysis using hydride generation in situ trapping electrothermal atomic absorption spectrometry and ruthenium or palladium modified graphite tubes.

    PubMed

    Yildirim, Emrah; Akay, Pınar; Arslan, Yasin; Bakirdere, Sezgin; Ataman, O Yavuz

    2012-12-15

    Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon their reaction with sodium borohydride using hydride generation. While Te(IV) can form H(2)Te, Te(VI) will not form any volatile species during the course of hydride formation and measurement by atomic absorption spectrometry. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Enhanced sensitivity was achieved by in situ trapping of the generated H(2)Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency for in situ trapping in pyrolytically coated graphite tube surface was found to be 15% when volatile analyte species are trapped for 60s at 300°C. LOD and LOQ values were calculated as 0.086 ng/mL and 0.29 ng/mL, respectively. Efficiency was increased to 46% and 36% when Pd and Ru surface modifiers were used, respectively. With Ru modified graphite tube 173-fold enhancement was obtained over 180 s trapping period with respect to ETAAS; the tubes could be used for 250 cycles. LOD values were 0.0064 and 0.0022 ng/mL for Pd and Ru treated ETAAS systems, respectively, for 180 s collection of 9.6 mL sample solution. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Application of high-resolution continuum source flame atomic absorption spectrometry to reveal, evaluate and overcome certain spectral effects in Pb determination of unleaded gasoline

    NASA Astrophysics Data System (ADS)

    Kowalewska, Zofia; Laskowska, Hanna; Gzylewski, Michał

    2017-06-01

    High-resolution continuum source and line source flame atomic absorption spectrometry (HR-CS FAAS and LS FAAS, respectively) were applied for Pb determination in unleaded aviation or automotive gasoline that was dissolved in methyl-isobutyl ketone. When using HR-CS FAAS, a structured background (BG) was registered in the vicinity of both the 217.001 nm and 283.306 nm Pb lines. In the first case, the BG, which could be attributed to absorption by the OH molecule, directly overlaps with the 217 nm line, but it is of relatively low intensity. For the 283 nm line, the structured BG occurs due to uncompensated absorption by OH molecules present in the flame. BG lines of relatively high intensity are situated at a large distance from the 283 nm line, which enables accurate analysis, not only when using simple variants of HR-CS FAAS but also for LS FAAS with a bandpass of 0.1 nm. The lines of the structured spectrum at 283 nm can have ;absorption; (maxima) or ;emission; (minima) character. The intensity of the OH spectra can significantly depend on the flame character and composition of the investigated organic solution. The best detection limit for the analytical procedure, which was 0.01 mg L- 1 for Pb in the investigated solution, could be achieved using HR-CS FAAS with the 283 nm Pb line, 5 pixels for the analyte line measurement and iterative background correction (IBC). In this case, least squares background correction (LSBC) is not recommended. However, LSBC (available as the ;permanent structures; option) would be recommended when using the 217 nm Pb line. In LS FAAS, an additional phenomenon related to the nature of the organic matrix (for example, isooctane or toluene) can play an important role. The effect is of continuous character and probably due to the simultaneous efficient correction of the continuous background (IBC) it is not observed in HR-CS FAAS. The fact that the effect does not depend on the flame character indicates that it is not radiation

  16. Identification of carbohydrates by matrix-free material-enhanced laser desorption/ionisation mass spectrometry.

    PubMed

    Hashir, Muhammad Ahsan; Stecher, Guenther; Bakry, Rania; Kasemsook, Saowapak; Blassnig, Bernhard; Feuerstein, Isabel; Abel, Gudrun; Popp, Michael; Bobleter, Ortwin; Bonn, Guenther K

    2007-01-01

    Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) is a sensitive mass spectrometric technique which utilises acidic materials as matrices for laser energy absorption, desorption and ionisation of analytes. These matrix materials produce background signals particularly in the low-mass range and make the detection and identification of small molecules difficult and nearly impossible. To overcome this problem this paper introduces matrix-free material-enhanced laser desorption/ionisation mass spectrometry (mf-MELDI-MS) for the screening and analysis of small molecules such as carbohydrates. For this purpose, 4,4'-azo-dianiline was immobilised on silica gel enabling the absorption of laser energy sufficient for successful desorption and ionisation of low molecular weight compounds. The particle and pore sizes, the solvent system for suspension and the sample preparation procedures have been optimised. The newly synthesised MELDI material delivered excellent spectra with regard to signal-to-noise ratio and detection sensitivity. Finally, wheat straw degradation products and Salix alba L. plant extracts were analysed proving the high performance and excellent behaviour of the introduced material. Copyright (c) 2007 John Wiley & Sons, Ltd.

  17. [Performance comparison of material tests for cadmium and lead in food contact plastics].

    PubMed

    Mutsuga, Motoh; Abe, Tomoyuki; Abe, Yutaka; Ishii, Rie; Itoh, Yuko; Ohno, Hiroyuki; Ohno, Yuichiro; Ozaki, Asako; Kakihara, Yoshiteru; Kaneko, Reiko; Kawamura, Yoko; Shibata, Hiroshi; Sekido, Haruko; Sonobe, Hironori; Takasaka, Noriko; Tajima, Yoshiyasu; Tanaka, Aoi; Nomura, Chie; Hikida, Akinori; Matsuyama, Sigetomo; Murakami, Ryo; Yamaguchi, Miku; Wada, Takenari; Watanabe, Kazunari; Akiyama, Hiroshi

    2014-01-01

    Based on the Japanese Food Sanitation Law, the performances of official and alternative material test methods for cadmium (Cd) and lead (Pb) in food contact plastics were compared. Nineteen laboratories participated to an interlaboratory study, and quantified Cd and Pb in three PVC pellets. in the official method, a sample is digested with H2SO4, taken up in HCl, and evaporated to dryness on a water bath, then measured by atomic absorption spectrometry (AAS) or inductively coupled plasma-optical emission spectrometry (ICP-OES). Statistical treatment revealed that the trueness, repeatability (RSDr) and reproducibility (RSDr) were 86-95%, 3.1-9.4% and 8.6-22.1%, respectively. The values of the performance parameters fulfilled the requirements , and the performances met the test specifications. The combination of evaporation to dryness on a hot plate and measurement by AAS or ICP-OES is applicable as an alternative method. However, the trueness and RSDr were inferior to those of the official method. The performance parameters obtained by using the microwave digestion method (MW method) to prepare test solution were better than those of the official method. Thus, the MW method is available as an alternative method. Induced coupled plasma-mass spectrometry (ICP-MS) is also available as an alternative method. However, it is necessary to ensure complete digestion of the sample.

  18. Comparison of several analytical methods for the determination of tin in geochemical samples as a function of tin speciation

    USGS Publications Warehouse

    Kane, J.S.; Evans, J.R.; Jackson, J.C.

    1989-01-01

    Accurate and precise determinations of tin in geological materials are needed for fundamental studies of tin geochemistry, and for tin prospecting purposes. Achieving the required accuracy is difficult because of the different matrices in which Sn can occur (i.e. sulfides, silicates and cassiterite), and because of the variability of literature values for Sn concentrations in geochemical reference materials. We have evaluated three methods for the analysis of samples for Sn concentration: graphite furnace atomic absorption spectrometry (HGA-AAS) following iodide extraction, inductively coupled plasma atomic emission spectrometry (ICP-OES), and energy-dispersive X-ray fluorescence (EDXRF) spectrometry. Two of these methods (HGA-AAS and ICP-OES) required sample decomposition either by acid digestion or fusion, while the third (EDXRF) was performed directly on the powdered sample. Analytical details of all three methods, their potential errors, and the steps necessary to correct these errors were investigated. Results showed that similar accuracy was achieved from all methods for unmineralized samples, which contain no known Sn-bearing phase. For mineralized samples, which contain Sn-bearing minerals, either cassiterite or stannous sulfides, only EDXRF and fusion ICP-OES methods provided acceptable accuracy. This summary of our study provides information which helps to assure correct interpretation of data bases for underlying geochemical processes, regardless of method of data collection and its inherent limitations. ?? 1989.

  19. Identifying a typology of men who use anabolic androgenic steroids (AAS).

    PubMed

    Zahnow, Renee; McVeigh, Jim; Bates, Geoff; Hope, Vivian; Kean, Joseph; Campbell, John; Smith, Josie

    2018-05-01

    Despite recognition that the Anabolic Androgenic Steroid (AAS) using population is diverse, empirical studies to develop theories to conceptualise this variance in use have been limited. In this study, using cluster analysis and multinomial logistic regression, we identify typologies of people who use AAS and examine variations in motivations for AAS use across types in a sample of 611 men who use AAS. The cluster analysis identified four groups in the data with different risk profiles. These groups largely reflect the ideal types of people who use AAS proposed by Christiansen et al. (2016): Cluster 1 (You Only Live Once (YOLO) type, n = 68, 11.1%) were younger and motivated by fat loss; Cluster 2 (Well-being type, n = 236, 38.6%) were concerned with getting fit; Cluster 3 (Athlete type, n = 155, 25.4%) were motivated by muscle and strength gains; Cluster 4 (Expert type, n = 152, 24.9%) were focused on specific goals (i.e. not 'getting fit'). The results of this study demonstrate the need to make information about AAS accessible to the general population and to inform health service providers about variations in motivations and associated risk behaviours. Attention should also be given to ensuring existing harm minimisation services are equipped to disseminate information about safe intra-muscular injecting and ensuring needle disposal sites are accessible to the different types. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Amino acid utilization and body composition of growing pigs fed processed soybean meal or rapeseed meal with or without amino acid supplementation.

    PubMed

    Hulshof, T G; van der Poel, A F B; Hendriks, W H; Bikker, P

    2017-07-01

    Feed ingredients used in swine diets are often processed to improve nutritional value. However, (over-)processing may result in chemical reactions with amino acids (AAs) that decrease their ileal digestibility. This study aimed to determine effects of (over-)processing of soybean meal (SBM) and rapeseed meal (RSM) on post-absorptive utilization of ileal digestible AAs for retention and on body AA composition of growing pigs. Soybean meal and RSM were processed by secondary toasting in the presence of lignosulfonate to obtain processed soybean meal (pSBM) and processed rapeseed meal (pRSM). Four diets contained SBM, pSBM, RSM or pRSM as sole protein source. Two additional diets contained pSBM or pRSM and were supplemented with crystalline AA to similar standardized ileal digestible (SID) AA level as the SBM or RSM diet. These diets were used to verify that processing affected AA retention by affecting ileal AA digestibility rather than post-absorptive AA utilization. The SID AA levels of the protein sources were determined in a previous study. In total, 59 pigs were used (initial BW of 15.6±0.7 kg) of which five were used to determine initial body composition at the start of the experiment. In total, 54 pigs were fed one of six experimental diets and were slaughtered at a BW of 40 kg. The organ fraction (i.e. empty organs plus blood) and carcass were analyzed separately for N and AA content. Post-absorptive AA utilization was calculated from AA retention and SID AA intake. An interaction between diet type, comprising effects of processing and supplementing crystalline AA, and protein source was observed for CP content in the organ fraction, carcass and empty body and for nutrient retention. Processing reduced CP content and nutrient retention more for SBM than for RSM. Moreover, processing reduced (P<0.001) the lysine content in the organ fraction for both protein sources. Supplementing crystalline AA ameliorated the effect of processing on these variables. Thus

  1. Long-term prognosis of AL and AA renal amyloidosis: a Japanese single-center experience.

    PubMed

    Ozawa, Masatoyo; Komatsuda, Atsushi; Ohtani, Hiroshi; Nara, Mizuho; Sato, Ryuta; Togashi, Masaru; Takahashi, Naoto; Wakui, Hideki

    2017-04-01

    Few studies have been conducted on the long-term prognosis of patients with amyloid light chain (AL) and amyloid A (AA) renal amyloidosis in the same cohort. We retrospectively examined 68 patients with biopsy-proven renal amyloidosis (38 AL and 30 AA). Clinicopathological findings at the diagnosis and follow-up data were evaluated in each patient. We analyzed the relationship between clinicopathological parameters and survival data. Significant differences were observed in several clinicopathological features, such as proteinuria levels, between the AL and AA groups. Among all patients, 84.2 % of the AL group and 93.3 % of the AA group received treatments for the underlying diseases of amyloidosis. During the follow-up period (median 18 months in AL and 61 months in AA), 36.8 % of the AL group and 36.7 % of the AA group developed end-stage renal failure requiring dialysis, while 71.1 % of the AL group and 56.7 % of the AA group died. Patient and renal survivals were significantly longer in the AA group than in the AL group. eGFR of >60 mL/min/1.73 m 2 at biopsy and an early histological stage of glomerular amyloid deposition were identified as low-risk factors. A multivariate analysis showed that cardiac amyloidosis and steroid therapy significantly influenced patient and renal survivals. Our results showed that heart involvement was the major predictor of poor outcomes in renal amyloidosis, and that the prognosis of AA renal amyloidosis was markedly better than that in previously reported cohorts. Therapeutic advances in inflammatory diseases are expected to improve the prognosis of AA amyloidosis.

  2. CV-Muzar - The Virtual Community Environment that Uses Multiagent Systems for Formation of Groups

    NASA Astrophysics Data System (ADS)

    de Marchi, Ana Carolina Bertoletti; Moraes, Márcia Cristina

    The purpose of this chapter is to present two agents' societies responsible for group formation (sub-communities) in CV-Muzar (Augusto Ruschi Zoobotanical Museum Virtual Community of the University of Passo Fundo). These societies are integrated to execute a data mining classification process. The first society is a static society that intends preprocessing data, investigating the information about groups in the CV-Muzar. The second society is a dynamical society that will make a classification process by analyzing the existing groups and look for participants that have common subjects in order to constitute a sub-community. The formation of sub-communities is a new functionality within the CV-Muzar that intends to bring the participants together according to two scopes: interest similarity and knowledge complementarities.

  3. The Presence of Mercury in the Tissues of Mallards (Anas platyrhynchos L.) from Włocławek Reservoir in Poland.

    PubMed

    Żarski, Jerzy F; Skibniewski, Michał; Skibniewska, Ewa; Żarski, Tadeusz P; Majdecka, Teresa

    2017-04-01

    The study aimed at determining the degree of mercury contamination of mallards, game waterbirds migrating from the regions of the unknown degree of contamination and establishing whether the consumption of their meat comprises a hazard to human health in view of the binding norms concerning the mercury content in food products. The investigations were carried out on 30 mallards shot during the duck shooting season in which mercury concentrations in the muscles, liver, and kidneys were determined using the cold vapor atomic absorption spectrometry (CV-AAS) method. The mean Hg concentration in the investigated tissues in all birds studied amounted to 0.110, 0.154, and 0.122 mg kg -1 for the muscles, kidneys, and liver, respectively. The study indicated statistically significant (p ≤ 0.01) positive correlation between all of the organs examined. Animals were divided into two groups differing in both absolute values of Hg concentrations and those measured in individual tissues. In particular organs of birds representing the first group, the presence of highly significant correlation (p ≤ 0.01) was observed in all organs examined. In the second group, highly significant positive correlation between Hg concentrations in the liver and kidneys and highly significant negative dependence between the liver and muscles was noted. The examinations revealed that some birds must have come from regions of a high degree of mercury contamination.

  4. Orange juice affects acylcarnitine metabolism in healthy volunteers as revealed by a mass-spectrometry based metabolomics approach.

    PubMed

    Moreira, Vanessa; Brasili, Elisa; Fiamoncini, Jarlei; Marini, Federico; Miccheli, Alfredo; Daniel, Hannelore; Lee, Jennifer Ji Hye; Hassimotto, Neuza Mariko Aymoto; Lajolo, Franco Maria

    2018-05-01

    Citrus juices, especially orange juice, constitute rich sources of bioactive compounds with a wide range of health-promoting activities. Data from epidemiological and in vitro studies suggest that orange juice (OJ) may have a positive impact on lipid metabolism. However, the effect of orange juice intake on blood lipid profile is still poorly understood. We have used two different blood samples, Dried Blood Spots (DBS) and plasma, to assess the effect of two-week orange juice consumption in healthy volunteers by a mass-spectrometry based metabolomics approach. DBS were analysed by liquid chromatography mass spectrometry (LC-MS) and plasma samples were analysed by the gas chromatography mass spectrometry (GC-MS). One hundred sixty-nine lipids including acylcarnitines (AC), lysophosphatidylcholines (LysoPC), (diacyl- and acyl-alkyl-) phosphatidylcholines (PC aa and PC ae) and sphingomyelins (SM) were identified and quantified in DBS. Eighteen fatty acids were identified and quantified in plasma. Multivariate analysis allowed to identify an increase in C3:1, C5-DC(C6-OH), C5-M-DC, C5:1-DC, C8, C12-DC, lysoPC18:3, myristic acid, pentadecanoic acid, palmitoleic and palmitic acid and a decrease in nervonic acid, C0, C2, C10, C10:1, C16:1, C16-OH, C16:1-OH, C18-OH, PC aa C40:4, PC ae C38:4, PC ae C42:3, PC ae C42:4 and cholesterol levels after orange juice intake. A two-week period of orange juice intake could affect fatty acids β-oxidation through mitochondrial and peroxisomal pathways, leading to an increase of short-chain acylcarnitines and a decrease of medium and long-chain acylcarnitines. This is the first report analyzing the effect of orange juice intake in healthy volunteers using a dried blood spot-based metabolomics approach. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. The Microjet of AA Tau

    NASA Astrophysics Data System (ADS)

    Cox, A. W.; Hilton, G. M.; Williger, G. M.; Grady, C. A.; Woodgate, B.

    2005-12-01

    The microjet of AA Tau A.W. Cox (Atholton High School, Columbia MD), G.M. Hilton (SSAI and GSFC), G.M. Williger (JHU and U. Louisville), C.A. Grady (Eureka Scientific and GSFC) B.Woodgate (NASA's GSFC) AA Tau is a classical T Tauri star with a spatially resolved disk viewed at approximately 70 degrees from pole-on. Photo-polarimetric variability of the star has been interpreted as being caused by the stellar magnetic field being inclined at 30 degrees with respect to the stellar rotation axis, producing a warp in the inner disk. Under these conditions, any jet should be less collimated than typical of T Tauri microjets, and should show signs of the jet axis precessing around the stellar rotation axis. When compared with the microjets imaged in the HST/STIS coronagraphic imaging survey, the AA Tau jet has an opening half-angle of approximately 10-15 degrees rather than the 3-5 degrees typical of the other T Tauri stars which have been coronagraphically imaged by HST/STIS. Using the HST data with ultra-narrowband imagery and long slit spectroscopy obtained with the Goddard Fabry-Perot and the Dual Imaging Spectrograph at the Apache Point Observatory 3.5m telescope, we derive the jet inclination, knot ejection epochs, and ejection frequency. We also compare the jet opening angle with model predictions. Apache Point Observatory observations with the Goddard Fabry-Perot were made through a grant of Director's Discretionary Time. Apache Point Observatory is operated by the Astrophysical Research Consortium. The GFP was supported under NASA RTOP 51-188-01-22 to GSFC. Grady is supported under NASA contract NNH05CD30C to Eureka Scientific.

  6. Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhandari, Deepak; Kertesz, Vilmos; Van Berkel, Gary J

    RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injectionmore » volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.« less

  7. Defective secretion of mucilage is the cellular basis for agravitropism in primary roots of Zea mays cv. Ageotropic

    NASA Technical Reports Server (NTRS)

    Miller, I.; Moore, R.

    1990-01-01

    Root caps of primary, secondary, and seminal roots of Z. mays cv. Kys secrete large amounts of mucilage and are in close contact with the root all along the root apex. These roots are strongly graviresponsive. Secondary and seminal roots of Z. mays cv. Ageotropic are also strongly graviresponsive. Similarly, their caps secrete mucilage and closely appress the root all along the root apex. However, primary roots of Z. mays cv. Ageotropic are non-responsive to gravity. Their caps secrete negligible amounts of mucilage and contact the root only at the extreme apex of the root along the calyptrogen. These roots become graviresponsive when their tips are coated with mucilage or mucilage-like materials. Peripheral cells of root caps of roots of Z. mays cv. Kys contain many dictyosomes associated with vesicles that migrate to and fuse with the plasmalemma. Root-cap cells of secondary and seminal (i.e. graviresponsive) roots of Z. mays cv. Ageotropic are similar to those of primary roots of Z. mays cv. Kys. However, root-cap cells of primary (i.e. non-graviresponsive) roots of Z. mays cv. Ageotropic have distended dictyosomal cisternae filled with an electron-dense, granular material. Large vesicles full of this material populate the cells and apparently do not fuse with the plasmalemma. Taken together, these results suggest that non-graviresponsiveness of primary roots of Z. mays cv. Ageotropic results from the lack of apoplastic continuity between the root and the periphery of the root cap. This is a result of negligible secretion of mucilage by cells along the edge of the root cap which, in turn, appears to be due to the malfunctioning of dictyosomes in these cells.

  8. AAS 227: Day 1

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or at astrobites.com, or catch ourlive-tweeted updates from the @astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Things kicked off last night at our undergraduate reception booth. Thanks to all of you who stopped by we were delightedto have so many people tell us that they already know about and useastrobites, and we were excited to introduce a new cohort of students at AAS to astrobites for the first time.Tuesday morning was the official start of the meeting. Here are just a few of the talks and workshops astrobiters attended today.Opening Address (by Becky Smethurst)The President of the AAS, aka our fearless leader Meg Urry kicked off the meeting this morning at the purely coffee powered hour of 8am this morning. She spoke about the importance of young astronomers at the meeting (heres looking at you reader!) and also the importance of the new Working Group for Accessibility and Disabilities (aka WGAD pronounced like wicked) at the AAS. The Society has made extra effort this year to make the conference accessible to all,a message which was very well received by everyone in attendance.Kavli Lecture: New Horizons Alan Stern (by Becky Smethurst)We were definitely spoilt with the first Plenary lecture at this years conference Alan Stern gave us a a review of the New Horizons mission of the Pluto Fly By (astrobites covered the mission back in July with this post). We were treated to beautiful images, wonderful results and a foray into geology.Before (Hubble) and after #NewHorizons. #thatisall #science #astro alanstern #aas227 pic.twitter.com/kkMt6RsSIR Science News (@topsciencething) January 5, 2016Some awesome facts from the lecture that blew my mind:New Horizons is now 2AU (!) beyond Pluto

  9. Comparison of lead and cadmium contents in cruciferous vegetables grown under diversified ecological conditions: Cracow region of Poland.

    PubMed

    Kapusta-Duch, Joanna; Leszczyńska, Teresa; Florkiewicz, Adam; Filipiak-Florkiewicz, Agnieszka

    2011-01-01

    The aim of the present study was to compare lead and cadmium contents in cruciferous vegetables grown under diversified ecological conditions for three consecutive years, independently of the climatic and agrotechnical conditions. The research was conducted in the Cracow region of Poland and tests vegetables near the Steelworks, from ecological farms, and from local markets. The heavy metal contents were determined using the validated Atomic Absorption Spectrometry method, including electrothermal atomization, with an ET-AAS graphite cuvette (Varian AA240Z, made by Varian). Cruciferous vegetables cultivated in the areas surrounding the steelworks were characterized by alarmingly high lead content versus ecological and commercially available vegetables, while the contents of this metal in vegetables from the two latter locations did not differ. It cannot be definitively stated that the origin of vegetables influenced their cadmium content.

  10. Efficacy of etanercept in patients with AA amyloidosis secondary to rheumatoid arthritis.

    PubMed

    Nakamura, T; Higashi, S; Tomoda, K; Tsukano, M; Baba, S

    2007-01-01

    The efficacy of biological therapies in rheumatoid arthritis (RA) is well known, but their hypothetical benefit in amyloid A (AA) amyloidosis secondary to RA still remains to be considered. We evaluated the efficacy and safety of etanercept in serum amyloid A (SAA) 1.3 allele Japanese patients with AA amyloidosis secondary to RA. Seven RA patients with histologically confirmed AA amyloidosis and renal involvement who were treated with etanercept were enrolled. They all had the SAA1.3 allele, which has been shown to be a risk factor not only for the association of AA amyloidosis but also for a poor prognosis in Japanese RA patients. Efficacy was assessed as a sustained decrease in RA inflammation and an amelioration of renal function. RA inflammation and AA amyloidosis were improved and stabilized after 43.4 +/- 16.5 weeks. At week 20 the number of tender (p = 0.017) and swollen (p = 0.017) joints, and levels of serum C-reactive protein (p = 0.018) and albumin (p = 0.045) had improved. The values for SAA, serum creatinine, calculated creatinine clearance, and proteinuria also ameliorated. No severe adverse events were observed. One patient eventually had to go on hemodialysis but her tolerance of etanercept remained stable. Etanercept can be used safely and effectively in AA amyloidosis secondary to RA with renal involvement, and is of clinical benefit in the short-term, even in patients on hemodialysis. It appears that SAA1.3 allele may be used as a clinical parameter for the introduction of etanercept in Japanese RA with AA amyloidosis.

  11. Effect of electrolytes and temperature on dications and radical cations of carotenoids: Electrochemical, optical absorption, and high-performance liquid chromatography studies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    He, Z.; Kispert, L.D.

    1999-11-25

    The effect of supporting electrolytes and temperature on the behavior of dications and radical cations of carotenoids is studied. Cyclic voltammograms (CVs) of canthaxanthin (I) at 23 and {minus}25 C show that Car{sup sm{underscore}bullet+} of I has similar stability during the time of the CV scan, when using tetrabutylammonium perchlorate (TBAPC), tetrabutylammonium tetrafluoroborate (TBATFB), or tetrabutylammonium hexafluorophosphate (TBAHFP) as supporting electrolyte. However, the stability of Car{sup 2+} decreases when using TBAPC or TBATFB; {beta}-carotene (II) shows similar behavior. The CV of I at {minus}25 C shows a strong cathodic wave (wave 6) near {minus}0.15 V (vs Ag) with an intensitymore » about half that of the neutral oxidation wave when TBAPC or TBATFB is the supporting electrolyte. When TBAHFP is used, wave 6 (ca. {minus}0.05 V vs Ag) is ca. 8 times weaker than when TBAPC or TBATFB is used. This wave results from the reduction of a species that may be a decay product of Car{sup 2+} of I. Results show that these electrolytes commonly used in electrochemical studies may affect the studied systems to different extents. In simultaneous bulk electrolysis (BE) and optical absorption spectroscopic measurements, the absorption band of Car{sup 2+} of I in the presence of 0.1 M TBAHFP can be observed by lowering the BE temperature to {minus}20 C. In the presence of 0.1 M TBAPC or TBATFB, this band is not observed, even at {minus}50 C. Isomerization of neutral I (as shown by HPLC and its blue absorption band shift) is observed only when the Car{sup 2+} absorption band is absent during BE. This observation, along with an increase of the neutral absorption band after stopping BE, suggests that the equilibrium Car + Car{sup 2+} {r{underscore}equilibrium} 2Car{sup {sm{underscore}bullet}+} is shifted to the left because Car{sup 2+} decays more quickly than Car{sup {sm{underscore}bullet}+} in the presence of electrolyte and this is a major path for formation of

  12. Light equation in eclipsing binary CV Boo: third body candidate in elliptical orbit

    NASA Astrophysics Data System (ADS)

    Bogomazov, A. I.; Kozyreva, V. S.; Satovskii, B. L.; Krushevska, V. N.; Kuznyetsova, Y. G.; Ehgamberdiev, S. A.; Karimov, R. G.; Khalikova, A. V.; Ibrahimov, M. A.; Irsmambetova, T. R.; Tutukov, A. V.

    2016-12-01

    A short period eclipsing binary star CV Boo is tested for the possible existence of additional bodies in the system with a help of the light equation method. We use data on the moments of minima from the literature as well as from our observations during 2014 May-July. A variation of the CV Boo's orbital period is found with a period of {≈}75 d. This variation can be explained by the influence of a third star with a mass of {≈}0.4 M_{⊙} in an eccentric orbit with e≈0.9. A possibility that the orbital period changes on long time scales is discussed. The suggested tertiary companion is near the chaotic zone around the central binary, so CV Boo represents an interesting example to test its dynamical evolution. A list of 14 minima moments of the binary obtained from our observations is presented.

  13. CV-990 Landing Systems Research Aircraft (LSRA) during final Space Shuttle tire test

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A Convair 990 (CV-990) was used as a Landing Systems Research Aircraft (LSRA) at NASA's Dryden Flight Research Center, Edwards, California, to test space shuttle landing gear and braking systems as part of NASA's effort to upgrade and improve space shuttle capabilities. The first flight at Dryden of the CV-990 with shuttle test components occurred in April 1993, and tests continued into August 1995, when this photo shows a test of the shuttle tires. The purpose of this series of tests was to determine the performance parameters and failure limits of the tires. This particular landing was on the dry lakebed at Edwards, but other tests occurred on the main runway there. The CV-990, built in 1962 by the Convair Division of General Dynamics Corp., Ft. Worth, Texas, served as a research aircraft at Ames Research Center, Moffett Field, California, before it came to Dryden.

  14. Electrochemical determination of dopamine and ascorbic acid at a novel gold nanoparticles distributed poly(4-aminothiophenol) modified electrode.

    PubMed

    Gopalan, Anantha Iyengar; Lee, Kwang-Pill; Manesh, Kalayil Manian; Santhosh, Padmanabhan; Kim, Jun Heon; Kang, Jae Soo

    2007-03-15

    A modified electrode is fabricated by embedding gold nanoparticles into a layer of electroactive polymer, poly(4-aminothiophenol) (PAT) on the surface of glassy carbon (GC) electrode. Cyclic voltammetry (CV) is performed to deposit PAT and concomitantly deposit Au nanoparticles. Field emission transmission electron microscopic image of the modified electrode, PAT-Au(nano)-ME, indicates the presence of uniformly distributed Au nanoparticles having the sizes of 8-10nm. Electrochemical behavior of the PAT-Au(nano)-ME towards detection of ascorbic acid (AA) and dopamine (DA) is studied using CV. Electrocatalytic determination of DA in the presence of fixed concentration of AA and vice versa, are studied using differential pulse voltammetry (DPV). PAT-Au(nano)-ME exhibits two well defined anodic peaks at the potential of 75 and 400mV for the oxidation of AA and DA, respectively with a potential difference of 325mV. Further, the simultaneous determination of AA and DA is studied by varying the concentration of AA and DA. PAT-Au(nano)-ME exhibits selectivity and sensitivity for the simultaneous determination of AA and DA without fouling by the oxidation products of AA or DA. PAT and Au nanoparticles provide synergic influence on the accurate electrochemical determination of AA or DA from a mixture having any one of the component (AA or DA) in excess. The practical analytical utilities of the PAT-Au(nano)-ME are demonstrated by the determination of DA and AA in dopamine hydrochloride injection and human blood serum samples.

  15. AAS Oral History Project - Seeking Planetary Scientist

    NASA Astrophysics Data System (ADS)

    Buxner, Sanlyn; Holbrook, Jarita

    2016-10-01

    Now in its fourth year, the AAS Oral History Project has interviewed over 100 space scientists from all over the world. Led by the AAS Historical Astronomy Division (HAD) and partially funded by the American Institute of Physics Niels Bohr Library and ongoing support from the AAS, volunteers have collected oral histories from space scientists at professional meetings starting in 2015, including AAS, DPS, and the IAU general assembly. Each interview lasts one and a half to two hours and focuses on interviewees' personal and professional lives. Questions include those about one's family, childhood, strong influences on one's scientific career, career path, successes and challenges, perspectives on how astronomy is changing as a field, and advice to the next generation. Each interview is audio recorded and transcribed, the content of which is checked with each interviewee. Once complete, interview transcripts are posted online as part of a larger oral history library at https://www.aip.org/history-programs/niels-bohr-library/oral-histories. We will present preliminary analysis of those interviewed including characterizing career status, age range, nationality, and primary field. Additionally, we will discuss trends beginning to emerge in analysis of participants' responses about data driven science and advice to the next generation. Future analysis will reveal a rich story of space scientists and will help the community address issues of diversity, controversies, and the changing landscape of science. We are actively recruiting individuals to be interviewed at this meeting from all stages of career from undergraduate students to retired and emeritus astronomers. We are especially interested in interviewing 40+E members of DPS. Contact Sanlyn Buxner to schedule an interview or to find out more information about the project (buxner@psi.edu). Contact Jarita Holbrook if you would like to become an interviewer for the project (astroholbrook@gmail.com).

  16. Matrix-assisted laser desorption/ionization time-of-flight vs. fast-atom bombardment and electrospray ionization mass spectrometry in the structural characterization of bacterial poly(3-hydroxyalkanoates).

    PubMed

    Impallomeni, Giuseppe; Ballistreri, Alberto; Carnemolla, Giovanni Marco; Franco, Domenico; Guglielmino, Salvatore P P

    2015-05-15

    Bacterial poly(3-hydroxyalkanoates) (PHAs) are an emergent class of plastic materials available from renewable resources. Their properties are strictly correlated with the comonomeric composition and sequence, which may be determined by various mass spectrometry approaches. In this paper we compare fast-atom bombardment (FAB) and electrospray ionization (ESI) to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of partially pyrolyzed samples. We determined the compositions and sequences of the medium-chain-length PHAs (mcl-PHAs) prepared by bacterial fermentation of Pseudomonas aeruginosa ATCC 27853 cultured in media containing fatty acids with 8, 12, 14, 18, and 20 carbon atoms as carbon sources by means of MALDI-TOFMS of pyrolyzates, and compared the results with those obtained by FAB- and ESI-MS in previous studies. MALDI matrices used were 9-aminoacridine (9-AA) and indoleacrylic acid (IAA). MALDI-TOFMS was carried out in negative ion mode when using 9-AA as a matrix, giving a semi-quantitative estimation of the 3-hydroxyacids constituting the PHAs, and in positive mode when using IAA, allowing us, through statistical analysis of the relative intensity of the oligomers generated by pyrolysis, to establish that the polymers obtained are true random copolyesters and not a mixture of homopolymers or copolymers. MALDI-TOFMS in 9-AA and IAA of partial pyrolyzates of mcl-PHAs represents a powerful method for the structural analysis of these materials. In comparison with FAB and ESI, MALDI provided an extended mass range with better sensitivity at higher mass and a faster method of analysis. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Treatment of AA amyloidosis in rheumatoid arthritis.

    PubMed

    Balakrishnan, C; Sule, A; Mittal, G; Gaitonde, S; Pathan, E; Rajadhyaksha, S; Deshpande, R B; Gurmeet, M; Samant, R; Joshi, V R

    2002-07-01

    Four patients of rheumatoid arthritis (RA) with biopsy confirmed AA amyloidosis were treated with chlorambucil. All had established but uncontrolled RA with a persistently raised ESR. Moderate (> 1 gm, < 3.5 gm/d) to nephrotic range (> 3.5 gm/d) proteinuria and a relatively well preserved renal function was noted in three patients. One patient had deranged renal function and required dialysis. On chlorambucil, there was complete recovery, partial improvement and no improvement in one patient each. The fourth patient required haemodialysis, did not tolerate chlorambucil and succumbed to the illness. Therapy with chlorambucil can benefit some patients of RA with AA amyloidosis. Leucopenia is the most important dose limiting side effect.

  18. Determination of lead at trace levels in mussel and sea water samples using vortex assisted dispersive liquid-liquid microextraction-slotted quartz tube-flame atomic absorption spectrometry.

    PubMed

    Erarpat, Sezin; Özzeybek, Gözde; Chormey, Dotse Selali; Bakırdere, Sezgin

    2017-12-01

    In this study, dispersive liquid-liquid microextraction (DLLME) and slotted quartz tube (SQT) were coupled to flame atomic absorption spectrometry (FAAS) to increase the sensitivity of lead. Conditions such as the formation of the lead-dithizone complex, efficiency of the DLLME method and the output of the SQT were systematically optimized to improve the detection limit for the analyte. The conventional FAAS system was improved upon by about 3.0 times with SQT-FAAS, 32 times with DLLME-FAAS and 142 times with DLLME-SQT-FAAS. The method was applicable over a wide linear range (10-500 μg L -1 ). The limit of detection (LOD) determined by DLLME-SQT-FAAS for seawater and mussel were 2.7 μg L -1 and 270 μg kg -1 , respectively. The percent recoveries obtained for mussel and seawater samples (spiked at 20 and 50 μg L -1 ) were 95-96% and 98-110%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Mass spectrometry.

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  20. Cryopreservation of banana's cv Grand Naine in vitro rhizomes.

    PubMed

    Londe, Luciana C N; Vendrame, Wagner A; Sanaei, Massy; Oliveira, Alexandre B DE

    2018-01-01

    The preservation of banana genetic material is usually performed through seedlings. However, most banana cultivars do not produce seed and are propagated vegetatively. Therefore, cryopreservation is a feasible technique that allows the preservation of banana genotypes indefinitely. For the success of cryopreservation protocols, the selection of cryoprotectants and pre-freezing techniques are important factor. Therefore, the objective of this study was to verify the effects of different cryoprotectants with and without 1% phloroglucinol and pre-cooling periods on the development of a protocol for cryopreservation of in vitro rhizomes ofMusa accuminata(AAA) cv Grand Naine banana. The addition of 1% phloroglucinol to the cryoprotective solutions, such as PVS2 enhanced recovery of cryopreserved banana rhizomes. In addition, pre-cooling of explants in ice for 3 hours in PVS2 + 1% of phloroglucinol allowed efficient cryopreservation of banana rhizomes, followed by successful recovery and regeneration of in vitro shoots of banana cv Grand Naine.