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Sample records for absorption spectrometric detection

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

    Directory of Open Access Journals (Sweden)

    Hesham Salem

    2005-01-01

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

  2. Graphite furnace atomic absorption spectrometric detection of vanadium in water and food samples after solid phase extraction on multiwalled carbon nanotubes.

    Science.gov (United States)

    Wadhwa, Sham Kumar; Tuzen, Mustafa; Gul Kazi, Tasneem; Soylak, Mustafa

    2013-11-15

    Vanadium(V) ions as 8-hydroxyquinoline chelates were loaded on multiwalled carbon nanotubes (MWNTs) in a mini chromatographic column. Vanadium was determined by graphite furnace atomic absorption spectrometry (GFAAS). Various analytical parameters including pH of the working solutions, amounts of 8-hydroxyquinoline, eluent type, sample volume, and flow rates were investigated. The effects of matrix ions and some transition metals were also studied. The column can be reused 250 times without any loss in its sorption properties. The preconcentration factor was found as 100. Detection limit (3 s) and limit of quantification (10 s) for the vanadium in the optimal conditions were observed to be 0.012 µg L(-1) and 0.040 μg L(-1), respectively. The capacity of adsorption was 9.6 mg g(-1). Relative standard deviation (RSD) was found to be 5%. The validation of the method was confirmed by using NIST SRM 1515 Apple leaves, NIST SRM 1570a Spinach leaves and GBW 07605 Tea certified reference materials. The procedure was applied to the determination of vanadium in tap water and bottled drinking water samples. The procedure was also successfully applied to microwave digested food samples including black tea, coffee, tomato, cabbage, zucchini, apple and chicken samples.

  3. Automated sequential injection-microcolumn approach with on-line flame atomic absorption spectrometric detection for implementing metal fractionation schemes of homogeneous and non-homogeneous solid samples of environmental interest

    DEFF Research Database (Denmark)

    Chomchoei, Roongrat; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    spectrometric detection and used for the determination of Cu as a model analyte, the potentials of this novel hyphenated approach are demonstrated by the ability of handling up to 300 mg sample of a nonhomogeneous sewage amended soil (viz., CRM 483). The three steps of the endorsed Standards, Measurements...

  4. Determination of cyanide by a flow injection analysis-atomic absorption spectrometric method.

    Science.gov (United States)

    López Gómez, A V; Martínez Calatayud, J

    1998-10-01

    A new flow injection analysis (FIA) procedure is proposed for the indirect atomic absorption spectrometric determination of cyanide. The FIA manifold is based on the insertion of the sample into a distilled water carrier, then the sample flows through a solid-phase reactor filled with silver iodide entrapped in polymeric resin beads. The calibration graph is linear over the range 0.2-6.0 mg l-1 of cyanide (correlation coefficient 0.9974), the detection limit is 0.1 mg l-1, the sample throughput is 193 h-1 and the RSD is 0.8%. The method is simple, quick and more selective than other published FIA procedures. The reproducibility obtained by using different solid-phase reactors and solutions is in the range 2.2-3.1% (RSD). The method was applied to the determination of cyanide in commercial samples such as pharmaceutical formulations and industrial electrolytic baths.

  5. Mass spectrometric detection, identification, and fragmentation of arseno-phytochelatins.

    Science.gov (United States)

    Schmied-Tobies, Maria I H; Arroyo-Abad, Uriel; Mattusch, Jürgen; Reemtsma, Thorsten

    2014-11-01

    Phytochelatins (PC) are cystein-rich oligopeptides in plants for coordination with toxic metals and metalloids via their thiol groups. The composition, structure, and mass spectrometric fragmentation of arseno-PC (As-PC) with PC of different degree of oligomerization (PC2-PC5) in solution were studied using liquid chromatography coupled in parallel to inductively coupled plasma mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. As-PC were detected from As(PC2) to As(PC5) with an increasing number of isomers that differ in the position of thiol groups bound to As. Thermodynamic modeling supported the identification process in case of these isomers. Mass spectrometric fragmentation of the As-PC does not follow the established pattern of peptides but is governed by the formation of series of As-containing annular cations, which coordinate to As via S, N, or O. Structure proposals for 30 As-PC fragment ions in the range m/z 147.92 to m/z 1290.18 are elaborated. Many of these fragment ions are characteristic to several As-PC and may be suited for a screening for As-PC in plant extracts. The mass spectrometric data offer the perspective for a future more sensitive determination of As-PC by means of liquid chromatography tandem mass spectrometry with multiple reaction monitoring.

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

    Directory of Open Access Journals (Sweden)

    Issa M

    2008-01-01

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

  7. Detection of formestane abuse by mass spectrometric techniques.

    Science.gov (United States)

    de la Torre, Xavier; Colamonici, Cristiana; Curcio, Davide; Jardines, Daniel; Molaioni, Francesco; Parr, Maria Kristina; Botrè, Francesco

    2014-01-01

    Formestane (4-hydroxy-androstenedione) is an aromatase inhibitor prohibited in sports and included, since 2004, in the list of prohibited substances updated yearly by the World Anti-Doping Agency (WADA). Since the endogenous production of formestane has been described, it is mandatory for the anti-doping laboratories to use isotope ratio mass spectrometry (IRMS) to establish the exogenous origin before issuing an adverse analytical finding. The described IRMS methods for formestane detection are time-consuming, requiring usually two consecutive liquid chromatographic sample purifications in order to have final extracts of adequate purity before the mass spectrometric analysis. After establishing a procedure for the determination of the origin of formestane by IRMS without the need of derivatization, and integrated in the overall analytical strategy of the laboratory for pseudo-endogenous steroids, a mass spectrometric analysis by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) of formestane metabolites was carried out in order to investigate whether other biomarkers of formestane abuse could be integrated in order to avoid time-consuming and expensive IRMS confirmations for formestane. From the metabolic studies performed, the inclusion of 3β,4α-dihydroxy-5α-androstan-17-one (4α-hydroxy-epiandosterone) in the routine GC-MS procedures has demonstrated to be diagnostic in order to reduce the number of unnecessary confirmations of the endogenous origin of formestane.

  8. Speciation analysis by gas chromatography with plasma source spectrometric detection

    Science.gov (United States)

    Łobiński, Ryszard; Adams, Freddy C.

    State-of-the-art species-selective analysis by gas chromatography (GC) with plasma source spectrometric detection is discussed for organometal and organometalloid compounds. Various plasmas, inductively coupled plasma, microwave induced plasma, capacitatively coupled plasma, direct current plasma and alternating current plasma, are characterized and critically compared as sources of radiation for atomic emission spectrometry and sources of ions for mass spectrometry. Interfaces between gas chromatography (packed, wide-bore, capillary and multicapillary) and plasma source spectrometry are characterized. Particular emphasis is given to applications of GC with plasma source detection to real-world analytical problems, which are comprehensively reviewed. The use of plasmas for the acquisition of auxiliary molecular information such as empirical formulae and structural information is discussed. Recent developments relating to sample preparation and presentation to the hyphenated system are addressed. The most significant trends in speciation analysis are highlighted.

  9. Absorption spectrum, mass spectrometric properties, and electronic structure of 1,2-benzoquinone.

    Science.gov (United States)

    Albarran, Guadalupe; Boggess, William; Rassolov, Vitaly; Schuler, Robert H

    2010-07-22

    Absorption spectrophotometric and mass spectrometric properties of 1,2-benzoquinone, prepared in aqueous solution by the hexachloroiridate(IV) oxidation of catechol and isolated by HPLC, are reported. Its absorption spectrum has a broad moderately intense band in the near UV with an extinction coefficient of 1370 M(-1)cm(-1) at its 389 nm maximum. The oscillator strength of this band contrasts with those of the order-of-magnitude stronger approximately 250 nm bands of most 1,4-benzoquinones. Gaussian analysis of its absorption spectrum indicates that it also has modestly intense higher energy bands in the 250-320 nm region. In atmospheric pressure mass spectrometric studies 1,2-benzoquinone exhibits very strong positive and negative mass 109 signals that result from the addition of protons and hydride ions in APCI and ESI ion sources. It is suggested that the hydride adduct is formed as the result of the highly polar character of ortho-quinone. On energetic collision the hydride adduct loses an H atom to produce the 1,2-benzosemiquinone radical anion. The present studies also show that atmospheric pressure mass spectral patterns observed for catechol are dominated by signals of 1,2-benzoquinone resulting from oxidation of catechol in the ion sources. Computational studies of the electronic structures of 1,2-benzoquinone, its proton and hydride ion adducts, and 1,2-benzosemiquinone radical anion are reported. These computational studies show that the structures of the proton and hydride adducts are similar and indicate that the hydride adduct is the proton adduct of a doubly negatively charged 1,2-benzoquinone. The contrast between the properties of 1,2- and 1,4-benzoquinone provides the basis for considerations on the effects of conjugation in aromatic systems.

  10. Status of mass spectrometric radiocarbon detection at ETHZ

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Martin; Maxeiner, Sascha; Wacker, Lukas; Synal, Hans-Arno

    2015-10-15

    A prototype of a mass spectrometric radiocarbon detection instrument without accelerator stage was built for the first time and set into operation at ETH Zurich. The system is designed as an experimental platform to optimize performance of {sup 14}C detection at low ion energies and to study the most relevant processes that may limit system performance. The optimized stripper unit incorporates differential pumping to maintain a low gas outflow and a revised tube design to better match the phase space volume of the ion beam at low energies. The system is fully operational and has demonstrated true radiocarbon dating capabilities. The overall beam transmission through the stripper tube is about 40% for the 1{sup +} charge state. Radiocarbon analyses with an overall precision of 0.6% were obtained on a single sample under regular measurement conditions. By analyzing multiple targets of the same sample material an uncertainty level of 0.3% has been reached. The background level corresponds to a radiocarbon age of 40,000 years.

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

    Science.gov (United States)

    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.

  12. Highly selective micro-sequential injection lab-on-valve (μSI-LOV) method for determination of ultra trace concentrations of nickel in saline matrices using detection by electrothermal atomic absorption spectrometr

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Jensen, Rikard;

    2006-01-01

    by electrothermal atomic absorption spectrometry (ETAAS). Based on the dimethylglyoxime (DMG) gravimetric procedure used for nickel analysis, the sample, as contained in pH 9.0 buffer, is, after on-line merging with the chelating reagent, transported to a reaction coil attached to one of the external ports...

  13. Retrospective detection of exposure to organophosphorus anti-cholinesterases: Mass spectrometric analysis of phosphylated human butyrylcholinesterase

    NARCIS (Netherlands)

    Fidder, A.; Hulst, A.G.; Noort, D.; Ruiter, R. de; Schans, M.J. van der; Benschop, H.P.; Langenberg, J.P.

    2002-01-01

    In this paper a novel and general procedure is presented for detection of organophosphate-inhibited human butyrylcholinesterase (HuBuChE), which is based on electrospray tandem mass spectrometric analysis of phosphylated nonapeptides obtained after pepsin digestion of the enzyme. The utility of this

  14. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  15. Gas chromatography of organic microcontaminants using atomic emission and mass spectrometric detection combined in one instrument (GC-AED/MS)

    NARCIS (Netherlands)

    Mol, H.G.J.; Hankemeier, T.; Brinkman, U.A.T.

    1999-01-01

    This study describes the coupling of an atomic-emission detector and mass-spectrometric detector to a single gas chromatograph. Splitting of the column effluent enables simultaneous detection by atomic-emission detection (AED) and mass spectrometry (MS) and yields a powerful system for the target an

  16. Experimental determination of the self-absorption factor for MTR plates by passive gamma spectrometric measurement

    Science.gov (United States)

    Berndt, R.; Mortreau, P.

    2011-07-01

    The measurement of the absolute activity or the mass of radioactive substances by gamma spectrometry needs to include a correction for the radiation absorption inside the source volume, the so-called self-absorption factor. It depends on geometry and material composition of the source, the detector geometry and on the geometrical arrangement of source and gamma radiation detector; it can be calculated if full information about all that is available. This article however describes how to determine the self-absorption factor from measurements if the radiation sources are plates of uranium fuel with typical parameters of nuclear fuel for MTR reactors and without using detail information on the source geometry, thus allowing easy inspection without relying on - potentially falsified - declarations on the internal properties of the fuel objects and without calculation.

  17. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples.

  18. Mass Spectrometric Detection of Bacterial Protein Toxins and Their Enzymatic Activity.

    Science.gov (United States)

    Kalb, Suzanne R; Boyer, Anne E; Barr, John R

    2015-08-31

    Mass spectrometry has recently become a powerful technique for bacterial identification. Mass spectrometry approaches generally rely upon introduction of the bacteria into a matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometer with mass spectrometric recognition of proteins specific to that organism that form a reliable fingerprint. With some bacteria, such as Bacillus anthracis and Clostridium botulinum, the health threat posed by these organisms is not the organism itself, but rather the protein toxins produced by the organisms. One such example is botulinum neurotoxin (BoNT), a potent neurotoxin produced by C. botulinum. There are seven known serotypes of BoNT, A-G, and many of the serotypes can be further differentiated into toxin variants, which are up to 99.9% identical in some cases. Mass spectrometric proteomic techniques have been established to differentiate the serotype or toxin variant of BoNT produced by varied strains of C. botulinum. Detection of potent biological toxins requires high analytical sensitivity and mass spectrometry based methods have been developed to determine the enzymatic activity of BoNT and the anthrax lethal toxins produced by B. anthracis. This enzymatic activity, unique for each toxin, is assessed with detection of the toxin-induced cleavage of strategically designed peptide substrates by MALDI-TOF mass spectrometry offering unparalleled specificity. Furthermore, activity assays allow for the assessment of the biological activity of a toxin and its potential health risk. Such methods have become important diagnostics for botulism and anthrax. Here, we review mass spectrometry based methods for the enzymatic activity of BoNT and the anthrax lethal factor toxin.

  19. Atomic Absorption Spectrometric Method for Estimation of Diclofenac sodium and Mefenamic acid in Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    Sunil Jawla

    2010-01-01

    Full Text Available Diclofenac sodium and Mefenamic acid have been quantified in tablet dosage form by atomic absorption spectrometry (AAS. These methods are based on formation of the metal complexes of Diclofenac sodium and Mefenamic acid with cupric chloride and cobaltous chloride. The first method is based on reaction of both the drugs with cupric chloride to give light blue colored metal complexes, which are then extracted with dichloromethane and digested with 0.1 M nitric acid. Both the drugs are indirectly estimated via determination of copper content in the formed complexes by AAS. The second method is based on the formation of pink colored complexes of both the drugs with cobaltous chloride. These metal complexes are extracted with dichloromethane and estimated via determination of cobalt content in the formed complexes after digestion with 0.1 M nitric acid by AAS.

  20. Mass spectrometric immunoassay

    Science.gov (United States)

    Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

    2007-12-04

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  1. An indirect atomic absorption spectrometric determination of ciprofloxacin, amoxycillin and diclofenac sodium in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    MAHMOUD MOHAMED ISSA

    2008-05-01

    Full Text Available A highly sensitive indirect atomic absorption spectrophotometric (AAS method has been developed for the determination of very low concentrations of ciprofloxacin, amoxycillin and diclofenac sodium. The method is based on the oxidation of these drugs with iron(III. The excess of iron(III was extracted into diethyl ether and then the iron(II in the aqueous layer was aspirated into an air–acetylene flame and determined by AAS. The linear concentration ranges were 25–400, 50–500 and 60–600 ng ml-1 for ciprofloxacin, amoxycillin and diclofenac sodium, respectively. The results were statistically compared with the official method using t- and f-test at p < 0.05. There were insignificant interferences from most of the excipients present. The intra- and inter-day assay coefficients of variation were less than 6.1 % and the recoveries ranged from 95 to 103 %. The method was applied for the analysis of these drug substances in their commercial pharmaceutical formulations.

  2. Mass spectrometric detection of short-lived drug metabolites generated in an electrochemical microfluidic chip.

    Science.gov (United States)

    van den Brink, Floris T G; Büter, Lars; Odijk, Mathieu; Olthuis, Wouter; Karst, Uwe; van den Berg, Albert

    2015-02-03

    The costs of drug development have been rising exponentially over the last six decades, making it essential to select drug candidates in the early drug discovery phases before proceeding to expensive clinical trials. Here, we present novel screening methods using an electrochemical chip coupled online to mass spectrometry (MS) or liquid chromatography (LC) and MS, to generate phase I and phase II drug metabolites and to demonstrate protein modification by reactive metabolites. The short transit time (∼4.5 s) between electrochemical oxidation and mass spectrometric detection, enabled by an integrated electrospray emitter, allows us to detect a short-lived radical metabolite of chlorpromazine which is too unstable to be detected using established test routines. In addition, a fast way to screen candidate drugs is established by recording real-time mass voltammograms, which allows one to identify the drug metabolites that are expected to be formed upon oxidation by applying a linear potential sweep and simultaneously detect oxidation products. Furthermore, detoxification of electrochemically generated reactive metabolites of paracetamol was mimicked by their adduct formation with the antioxidant glutathione. Finally, the potential toxicity of reactive metabolites can be investigated by the modification of proteins, which was demonstrated by modification of carbonic anhydrase I with electrochemically generated reactive metabolites of paracetamol. With this series of experiments, we demonstrate the potential of this electrochemical chip as a complementary tool for a variety of drug metabolism studies in the early stages of drug discovery.

  3. Analysis of endocrine disrupting pesticides by capillary GC with mass spectrometric detection.

    Science.gov (United States)

    Matisová, Eva; Hrouzková, Svetlana

    2012-09-01

    Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC) and fast CGC with mass spectrometric detection (MS) has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP) residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  4. Analysis of Endocrine Disrupting Pesticides by Capillary GC with Mass Spectrometric Detection

    Directory of Open Access Journals (Sweden)

    Svetlana Hrouzková

    2012-09-01

    Full Text Available Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC and fast CGC with mass spectrometric detection (MS has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  5. Development of a cloud point extraction and preconcentration method for Cd and Ni prior to flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Manzoori, Jamshid L. [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)]. E-mail: manzoori@tabrizu.ac.ir; Karim-Nezhad, Ghasem [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2004-09-13

    In this work a new cloud point extraction (CPE) methodology was developed for the separation and preconcentration of cadmium and nickel. The analyte in the initial aqueous solution was complexed with dithizone and Triton X-114 was added as surfactant. After phase separation, based on the cloud point of the mixture, and dilution of the surfactant-rich phase with tetrahydrofuran (THF), the enriched analytes were determined by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions and preconcentration of only 10 ml of sample in the presence of 0.05% Triton X-114, the enhancement factors of 52 and 39 and the detection limits of 0.31 {mu}g l{sup -1} and 1.2 {mu}g l{sup -1} were obtained for cadmium and nickel respectively. The proposed method was applied satisfactorily to the determination of cadmium and nickel in water samples.

  6. Membrane filtration of nickel(II) on cellulose acetate filters for its preconcentration, separation, and flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Soylak, Mustafa [Chemistry Dept., Faculty of Science Arts, University of Erciyes, Kayseri (Turkey); Unsal, Yunus Emre; Aydin, Ayse [Fen Bilimleri Enstitusu, University of Erciyes, Kayseri (Turkey); Kizil, Nebiye [Saglik Bilimleri Enstitusu, University of Erciyes, Kayseri (Turkey)

    2010-01-15

    An enrichment method for trace amounts of Ni(II), as 8-hydroxyquinoline chelates, has been established on a cellulose acetate membrane filter. Ni(II)-8-hydroxyquinoline chelates adsorbed on a membrane filter were eluted using 5 mL of 1 M HNO{sub 3}. The eluent nickel concentration was determined by a flame atomic absorption spectrometer. The influence of some analytical parameters, including pH, amount of reagent, sample volume, etc., on recovery was investigated. The interference of co-existent ions was studied. The nickel detection limit was 4.87 {mu}g/L. The method was applied to real samples for the determination of nickel(II) ions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  7. Solid phase extraction of gold(III) on Amberlite XAD-2000 prior to its flame atomic absorption spectrometric determination.

    Science.gov (United States)

    Elci, Latif; Sahan, Derya; Basaran, Aydan; Soylak, Mustafa

    2007-09-01

    A solid phase extraction method for the determination of gold(III) at trace levels by flame atomic absorption spectrometer (FAAS) was developed. The method was based on retention of gold as chloro complexes through the Amberlite XAD-2000. The effect of some analytical parameters including hydrochloric acid concentration, sample volume, sample and eluent flow rates, eluent volume, eluent concentration and interfering ions on the recovery of gold(III) was investigated. The retention of gold(III) from 1.5 mol l(-1) HCl solution and the recovery of gold with 0.07 mol l(-1) NH3 solution were quantitative (>or=95%). The relative standard deviation (RSD) was calculated as 3.2% (n = 10). The detection limit for gold was 2 microg l(-1). The accuracy was checked with the determination of gold spiked an artificial seawater and a pure copper samples.

  8. On-line preconcentration of copper as its pyrocatechol violet complex on Chromosorb 105 for flame atomic absorption spectrometric determinations

    Energy Technology Data Exchange (ETDEWEB)

    Buke, Berrin [Chemistry Department, Science and Arts Faculty, Pamukkale University, 20020 Denizli (Turkey); Divrikli, Umit [Chemistry Department, Science and Arts Faculty, Pamukkale University, 20020 Denizli (Turkey)], E-mail: udivrikli@pamukkale.edu.tr; Soylak, Mustafa [Chemistry Department, Science and Arts Faculty, Erciyes University, 38039 Kayseri (Turkey); Elci, Latif [Chemistry Department, Science and Arts Faculty, Pamukkale University, 20020 Denizli (Turkey)

    2009-04-30

    An on-line solid phase extraction method for the preconcentration and determination of Cu(II) by flame atomic absorption spectrometry (FAAS) has been described. It is based on the adsorption of copper(II) ion onto a home made mini column of Chromosorb 105 resin loaded with pyrocatechol violet at the pH range of 5.0-8.0, then eluted with 1 mol L{sup -1} HNO{sub 3}. Several parameters, such as pH of the sample solution, amount of Chromosorb 105 resin, volume of sample and eluent, type of eluent, flow rates of sample and eluent, governing the efficiency and throughput of the method were evaluated. The concentration of the copper ion detected after preconcentration was in agreement with the added amount. At optimized conditions, for 15 min of preconcentration time (30 mL of sample volume), the system achieved a detection limit of 0.02 {mu}g L{sup -1}, with relative standard deviation 1.1% at 0.03 {mu}g mL{sup -1} copper. The present method was found to be applicable to the preconcentration of Cu(II) in natural water samples.

  9. Mass spectrometric detection of proteins in non-aqueous media : the case of prion proteins in biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Douma, M.D.; Kerr, G.M.; Brown, R.S.; Keller, B.O.; Oleschuk, R.D. [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemistry

    2008-08-15

    This paper presented a filtration method for detecting protein traces in non-aqueous media. The extraction technique used a mixture of acetonitrile, non-ionic detergent and water along with filter disks with embedded C{sub 8}-modified silica particles to capture the proteins from non-aqueous samples. The extraction process was then followed by an elution of the protein from the filter disk and direct mass spectrometric detection and tryptic digestion with peptide mapping and MS/MS fragmentation of protein-specific peptides. The method was used to detect prion proteins in spiked biodiesel samples. A tryptic peptide with the sequence YGQGSPGGNR was used for unambiguous identification. Results of the study showed that the method is suitable for the large-scale testing of protein impurities in tallow-based biodiesel production processes. 33 refs., 6 figs.

  10. Separation and enrichment of gold(III) from environmental samples prior to its flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Senturk, Hasan Basri; Gundogdu, Ali [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 28049 Giresun (Turkey); Duran, Celal [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey)], E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Arts and Sciences, Pamukkale University, 20020 Denizli (Turkey); Tufekci, Mehmet [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2007-10-22

    A simple and accurate method was developed for separation and enrichment of trace levels of gold in environmental samples. The method is based on the adsorption of Au(III)-diethyldithiocarbamate complex on Amberlite XAD-2000 resin prior to the analysis of gold by flame atomic absorption spectrometry after elution with 1 mol L{sup -1} HNO{sub 3} in acetone. Some parameters including nitric acid concentration, eluent type, matrix ions, sample volume, sample flow rate and adsorption capacity were investigated on the recovery of gold(III). The recovery values for gold(III) and detection limit of gold were greater than 95% and 16.6 {mu}g L{sup -1}, respectively. The preconcentration factor was 200. The relative standard deviation of the method was <6%. The adsorption capacity of the resin was 12.3 mg g{sup -1}. The validation of the presented procedure was checked by the analysis of CRM-SA-C Sandy Soil certified reference material. The presented procedure was applied to the determination of gold in some environmental samples.

  11. Highly sensitive detection using Herriott cell for laser absorption spectroscopy

    Science.gov (United States)

    Zhao, Chongyi; Song, Guangming; Du, Yang; Zhao, Xiaojun; Wang, Wenju; Zhong, Liujun; Hu, Mai

    2016-11-01

    The tunable diode laser absorption spectroscopy combined with the long absorption path technique is a significant method to detect harmful gas. The long optical path could come true by Herriott cell reducing the size of the spectrometers. A 15 cm long Herriott cell with 28.8 m optical absorption path after 96 times reflection was designed that enhanced detection sensitivity of absorption spectroscopy. According to the theory data of calculation, Herriott cell is analyzed and simulated by softwares Matlab and Lighttools.

  12. Cloud Point Extraction and Flame Atomic Absorption Spectrometric Determination of Lead, Cadmium and Palladium in Some Food and Biological Samples

    Directory of Open Access Journals (Sweden)

    M. Soylak

    2011-12-01

    Full Text Available The proposed method is based on the complexation of the Pb2+, Cd2+ and Pd2+ ions with 3-(1-(1-H-Indol-3-Yl-3-phenylallyl-1H-indole (IPAI at pH 8.0 in the presence of Triton X-114. The phase separation occured when micellar solution was heated at 55 ◦C. The surfactant-rich phase, diluted to 0.5 mL via 1.0 mol L−1 nitric acid in methanol was directly introduced into the nebulizer of the flame atomic absorption spectrometry (FAAS. Influence of variables such as pH, amount of ligand and Triton X-114, heating time and temperature were evaluated and optimized. The optimized enhancement factors for Pb2+, Cd2+ and Pd2+ ions were 22, 33 and 23, respectively and the detection limit (DLs was between of 1.6–2.6 µgL−1. The relative standard deviation (RSD of each ion was found to be less than 4.6% at 100 µgL−1. In addition, the calibration graphs were linear in the range of 0.01-0.22 μg mL−1 for Cd2+ ion, 0.018-0.26 μg mL−1 for Pb2+ ion and 0.02-0.27 μg mL−1 for Pd2+ ion with the correlation coefficients in the range of 0.995–0.999.

  13. Selective cloud point extraction and graphite furnace atomic absorption spectrometric determination of molybdenum (VI) ion in seawater samples

    Energy Technology Data Exchange (ETDEWEB)

    Filik, Hayati, E-mail: filik@istanbul.edu.tr [Istanbul University, Faculty of Engineering, Department of Chemistry, Avcilar, 34320 Istanbul (Turkey); Cengel, Tayfun; Apak, Resat [Istanbul University, Faculty of Engineering, Department of Chemistry, Avcilar, 34320 Istanbul (Turkey)

    2009-09-30

    A cloud point extraction process using the nonionic surfactant Triton X-114 to extract molybdenum from aqueous solutions was investigated. The method is based on the complexation reaction of Mo(VI) with 1,2,5,8-tetrahydroxyanthracene-9,10-dione (quinalizarine: QA) and micelle-mediated extraction of the complex. The enriched analyte in the surfactant-rich phase was determined by graphite furnace atomic absorption spectrometry (GFAAS). The optimal extraction and reaction conditions (e.g. pH, reagent and surfactant concentrations, temperature, incubation and centrifugation times) were evaluated and optimized. Under the optimized experimental conditions, the limit of detection (LOD) for Mo(VI) was 7.0 ng L{sup -1} with an preconcentration factor of {approx}25 when 10 mL of sample solution was preconcentrated to 0.4 mL. The proposed method (with extraction) showed linear calibration within the range 0.03-0.6 {mu}g L{sup -1}. The relative standard deviation (RSD) was found to be 3.7% (C{sub Mo(VI)} = 0.05 {mu}g L{sup -1}, n = 5) for pure standard solutions, whereas RSD for the recoveries from real samples ranged between 2 and 8% (mean RSD = 3.9%). The method was applied to the determination of Mo(VI) in seawater and tap water samples with a recovery for the spiked samples in the range of 98-103%. The interference effect of some cations and anions was also studied. In the presence of foreign ions, no significant interference was observed. In order to verify the accuracy of the method, a certified reference water sample was analysed and the results obtained were in good agreement with the certified values.

  14. Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection

    DEFF Research Database (Denmark)

    Justesen, U.; Knuthsen, Pia; Leth, Torben

    1998-01-01

    A high-performance liquid chromatographic (HPLC) separation method viith photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained...

  15. Design of Optoelectric Detection Circuit for Difference Absorption Gas Sensor

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Since the gas infrared absorption spectrum linewidth is only several nanometers occupying the source intensity of several in a thousand, it is even less than the noise of light source. The signal of gas absorption is submerged in the noise, so it is impossible to measure the concentration of gas with spectrum absorption directly. According to the principle and parameters of difference absorption system of CH4 gas, a detection circuit consisted of the lock-in amplifier is designed. The experiment results indicated that the detection circuit can satisfy the demand of the whole system, and the limit concentration is 150×10-6.

  16. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium and nickel in drinking and wastewater samples.

    Science.gov (United States)

    Naeemullah; Kazi, Tasneem G; Shah, Faheem; Afridi, Hassan I; Baig, Jameel Ahmed; Soomro, Abdul Sattar

    2013-01-01

    A simple method for the preconcentration of cadmium (Cd) and nickel (Ni) in drinking and wastewater samples was developed. Cloud point extraction has been used for the preconcentration of both metals, after formation of complexes with 8-hydroxyquinoline (8-HQ) and extraction with the surfactant octylphenoxypolyethoxyethanol (Triton X-114). Dilution of the surfactant-rich phase with acidified ethanol was performed after phase separation, and the Cd and Ni contents were measured by flame atomic absorption spectrometry. The experimental variables, such as pH, amounts of reagents (8-HQ and Triton X-114), temperature, incubation time, and sample volume, were optimized. After optimization of the complexation and extraction conditions, enhancement factors of 80 and 61, with LOD values of 0.22 and 0.52 microg/L, were obtained for Cd and Ni, respectively. The proposed method was applied satisfactorily for the determination of both elements in drinking and wastewater samples.

  17. Standard test method for graphite furnace atomic absorption spectrometric determination of lead and cadmium extracted from ceramic foodware

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method covers procedures for using graphite furnace atomic absorption spectroscopy (GFAAS) to quantitatively determine lead and cadmium extracted by acetic acid at room temperature from the food-contact surface of foodware. The method is applicable to food-contact surfaces composed of silicate-based materials (earthenware, glazed ceramicware, decorated ceramicware, decorated glass, and lead crystal glass) and is capable of determining lead concentrations greater than 0.005 to 0.020 g/mL and cadmium concentrations greater than 0.0005 to 0.002 g/mL, depending on instrument design. 1.2 This test method also describes quality control procedures to check for contamination and matrix interference during GFAAS analyses and a specific sequence of analytical measurements that demonstrates proper instrument operation during the time period in which sample solutions are analyzed. 1.3 Cleaning and other contamination control procedures are described in this test method. Users may modify contamination cont...

  18. Capillary liquid chromatography using laser-based and mass spectrometric detection. Final technical progress report, September 1, 1989--January 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M.J.; Cook, K.D.

    1992-09-01

    In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

  19. An atomic absorption spectrometric method for the determination of phosphorus in foodstuffs using the bismuth phosphomolybdate complex

    Directory of Open Access Journals (Sweden)

    LJILJANA V. MIHAJLOVIC

    2000-06-01

    Full Text Available A new indirect AAS method using the bismuth phosphomolybdate complex for the determination of phosphorus in foodstuffs is suggested. The bismuth phosphomolybdate complex in acid medium was extacted with isobutyl methylketone and the phosphorus was determined through bismuth in an air/acetylene flame by utilising the 223.06 nm resonance line of bismuth. The interference caused by antimony and titanium can be neglected in the presence of excess of bismuth. The detection limit of the method is 0.008 mg/mL of phosphorus.

  20. Thermally detected optical absorption in sophisticated nitride structures

    Energy Technology Data Exchange (ETDEWEB)

    Vasson, A.; Leymarie, J. [LASMEA-UMR 6602 CNRS-UBP, 63177 Aubiere Cedex (France); Shubina, T.V. [Ioffe Physico-Technical Institute, RAS, St. Petersburg 194021 (Russian Federation)

    2005-02-01

    The thermally detected optical absorption (TDOA) is applied to elucidate peculiarities of absorption in nitride structures of unusual morphology like GaN nanocolumns or InN layers with various imperfections. A study of GaN structures permits us to establish position of an absorption edge in TDOA spectra. We demonstrate that the absorption edge is different in GaN regions of opposite polarities. In InN with metallic In inclusions, this technique enable separation of InN interband absorption and extinction related to the Mie resonances, if the latter are below the principal absorption edge. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. A Mass Spectrometric Analysis Method Based on PPCA and SVM for Early Detection of Ovarian Cancer.

    Science.gov (United States)

    Wu, Jiang; Ji, Yanju; Zhao, Ling; Ji, Mengying; Ye, Zhuang; Li, Suyi

    2016-01-01

    Background. Surfaced-enhanced laser desorption-ionization-time of flight mass spectrometry (SELDI-TOF-MS) technology plays an important role in the early diagnosis of ovarian cancer. However, the raw MS data is highly dimensional and redundant. Therefore, it is necessary to study rapid and accurate detection methods from the massive MS data. Methods. The clinical data set used in the experiments for early cancer detection consisted of 216 SELDI-TOF-MS samples. An MS analysis method based on probabilistic principal components analysis (PPCA) and support vector machine (SVM) was proposed and applied to the ovarian cancer early classification in the data set. Additionally, by the same data set, we also established a traditional PCA-SVM model. Finally we compared the two models in detection accuracy, specificity, and sensitivity. Results. Using independent training and testing experiments 10 times to evaluate the ovarian cancer detection models, the average prediction accuracy, sensitivity, and specificity of the PCA-SVM model were 83.34%, 82.70%, and 83.88%, respectively. In contrast, those of the PPCA-SVM model were 90.80%, 92.98%, and 88.97%, respectively. Conclusions. The PPCA-SVM model had better detection performance. And the model combined with the SELDI-TOF-MS technology had a prospect in early clinical detection and diagnosis of ovarian cancer.

  2. A Mass Spectrometric Analysis Method Based on PPCA and SVM for Early Detection of Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Jiang Wu

    2016-01-01

    Full Text Available Background. Surfaced-enhanced laser desorption-ionization-time of flight mass spectrometry (SELDI-TOF-MS technology plays an important role in the early diagnosis of ovarian cancer. However, the raw MS data is highly dimensional and redundant. Therefore, it is necessary to study rapid and accurate detection methods from the massive MS data. Methods. The clinical data set used in the experiments for early cancer detection consisted of 216 SELDI-TOF-MS samples. An MS analysis method based on probabilistic principal components analysis (PPCA and support vector machine (SVM was proposed and applied to the ovarian cancer early classification in the data set. Additionally, by the same data set, we also established a traditional PCA-SVM model. Finally we compared the two models in detection accuracy, specificity, and sensitivity. Results. Using independent training and testing experiments 10 times to evaluate the ovarian cancer detection models, the average prediction accuracy, sensitivity, and specificity of the PCA-SVM model were 83.34%, 82.70%, and 83.88%, respectively. In contrast, those of the PPCA-SVM model were 90.80%, 92.98%, and 88.97%, respectively. Conclusions. The PPCA-SVM model had better detection performance. And the model combined with the SELDI-TOF-MS technology had a prospect in early clinical detection and diagnosis of ovarian cancer.

  3. Hydrophilic interaction liquid chromatography with tandem mass spectrometric detection applied for analysis of pteridines in two Graphosoma species (Insecta: Heteroptera).

    Science.gov (United States)

    Kozlík, Petr; Krajíček, Jan; Kalíková, Květa; Tesařová, Eva; Cabala, Radomír; Exnerová, Alice; Stys, Pavel; Bosáková, Zuzana

    2013-07-01

    A new separation method involving hydrophilic interaction chromatography with tandem mass spectrometric detection has been developed for the analysis of pteridines, namely biopterin, isoxanthopterin, leucopterin, neopterin, xanthopterin and erythropterin in the cuticle of heteropteran insect species. Two columns, Atlantis HILIC Silica and ZIC(®)-HILIC were tested for the separation of these pteridines. The effect of organic modifier content, buffer type, concentration and pH in mobile phase on retention and separation behavior of the selected pteridines was studied and the separation mechanism was also investigated. The optimized conditions for the separation of pteridines consisted of ZIC(®)-HILIC column, mobile phase composed of acetonitrile/5mM ammonium acetate, pH 6.80, 85/15 (v/v), flow rate 0.5mL/min and column temperature 30°C. Detection was performed by tandem mass spectrometry operating in electrospray ionization with Agilent Jet Stream technology using the selected reaction monitoring mode. The optimized method provided a linearity range from 0.3 to 5000ng/mL (r>0.9975) and repeatability with relative standard deviation<8.09% for all the studied pteridines. The method was applied to the analysis of pteridines in the cuticle of larvae and three adult color forms of Graphosoma lineatum and one form of Graphosoma semipunctatum (Insecta: Hemiptera: Heteroptera: Pentatomidae). The analysis shows that different forms of Graphosoma species can be characterized by different distribution of individual pteridines, which affects the coloration of various forms. Only isoxanthopterin was found in all the five forms tested.

  4. Capillary liquid chromatography using laser-based and mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M.J.; Cook, K.D.

    1990-01-01

    The DOE-supported research performed during the past year has mainly focused on investigating and minimizing three problems that limit the practical utility of these capillary electrokinetic separation techniques in chemical analysis. (1) Analyses are hindered by poor reproducibility. This is largely a result of complicated and irreproducible capillary wall-solute interactions that often result in adsorption and mobility changes. (2) While the (micellar electrokinetic capillary chromatography) (MECC) technique permits the separations of neutral solutes, hydrophobic compounds are difficult to separate and manipulation of capacity factors (k's) is critically important. (3) The very small solute band volumes require that on-column detection be performed (usually optical detection) and this seriously limits detectability. In addition to these projects, the electrokinetic equivalent of affinity chromatography and development of remote fiber-optic sensors to measure chemical carcinogens and other compounds have been investigated. 5 refs., 2 figs.

  5. Cloud point extraction and flame atomic absorption spectrometric determination of trace lead in freshwater fish%浊点萃取-火焰原子吸收光谱法测定淡水鱼中痕量铅

    Institute of Scientific and Technical Information of China (English)

    王秀峰; 李龙; 张春丽; 林朋; 崔书亚

    2012-01-01

    采用以双硫腙为络合剂、Triton X- 100为表面活性剂的新型浊点萃取体系富集淡水鱼中的痕量铅,并用火焰原子吸收光谱法对其进行测定.探讨了溶液pH、表面活性剂浓度、络合剂用量、平衡温度、平衡时间等对浊点萃取及测定灵敏度的影响,优化了实验条件.在最佳条件下测得铅的检出限为0.090μg/L,校准曲线相关系数为0.9999.该方法已用于淡水鱼中痕量铅的测定.%A new cloud point extraction-flame atomic absorption spectrometric method has been developed to determine trace lead. Dithizone was selected as the complex reagent and Triton X - 100 as the surfactant. Effects of pH, concentrations of surfactant and complex reagent, equilibrium temperature and time on the efficiency and sensitivity of cloud point extraction were investigated. Under optimal conditions, the calibration curve was linear over the concentration range of 0. 1 - 60μg/L with correlation coefficient of 0. 9999 and detection limit of 0. 090 μg/L. The present method was applied to the determination of trace lead in freshwater fish samples with satisfactory results.

  6. Mass Spectrometric Detection of Botulinum Neurotoxin by Measuring its Activity in Serum and Milk

    Science.gov (United States)

    Kalb, Suzanne R.; Pirkle, James L.; Barr, John R.

    Botulinum neurotoxins (BoNTs) are bacterial protein toxins which are considered likely agents for bioterrorism due to their extreme toxicity and high availability. A new mass spectrometry based assay called Endopep MS detects and defines the toxin serotype in clinical and food matrices via toxin activity upon a peptide substrate which mimics the toxin's natural target. Furthermore, the subtype of the toxin is differentiated by employing mass spectrometry based proteomic techniques on the same sample. The Endopep-MS assay selectively detects active BoNT and defines the serotype faster and with sensitivity greater than the mouse bioassay. One 96-well plate can be analyzed in under 7 h. On higher level or "hot" samples, the subtype can then be differentiated in less than 2 h with no need for DNA.

  7. Species-selective analysis by microcolumn multicapillary gas chromatography with inductively coupled plasma mass spectrometric detection.

    Science.gov (United States)

    Rodriguez, I; Mounicou, S; Lobiński, R; Sidelnikov, V; Patrushev, Y; Yamanaka, M

    1999-10-15

    A glass rod (5-20 cm long, 2 mm o.d.) containing more than 1200 parallel microchannels ( 100 theoretical plates cm-1) GC column by coating the inside of each channel in a way that compensated for the dispersion of the channel inner diameter. The columns were evaluated for the separation of mixtures of several organometallic (Hg, Sn, Pb) compounds prior to on-line sensitive metalselective detection by ICPMS. Chromatographic separation conditions were optimized to enable a rapid (within a maximum 30 s) multielemental speciation analysis. Absolute detection limits were 0.1 pg for Hg, 0.05 pg for Sn, and 0.03 pg for Pb using the carrier gas flows of approximately 200 mL min-1. The microcolumn multicapillary GC/ICPMS developed was applied to the analysis of a number of environmental samples. The results were validated with certified reference materials for tin (BCR477, PACS-2) and mercury (DORM-1, TORT-1).

  8. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    2014-10-01

    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  9. Determination of suvorexant in human plasma using 96-well liquid-liquid extraction and HPLC with tandem mass spectrometric detection.

    Science.gov (United States)

    Breidinger, S A; Simpson, R C; Mangin, E; Woolf, E J

    2015-10-01

    A method, using liquid chromatography with tandem mass spectrometric detection (LC-MS/MS), was developed for the determination of suvorexant (MK-4305, Belsomra(®)), a selective dual orexin receptor antagonist for the treatment insomnia, in human plasma over the concentration range of 1-1000ng/mL. Stable isotope labeled (13)C(2)H3-suvorexant was used as an internal standard. The sample preparation procedure utilized liquid-liquid extraction, in the 96-well format, of a 100μL plasma sample with methyl t-butyl ether. The compounds were chromatographed under isocratic conditions on a Waters dC18 (50×2.1mm, 3μm) column with a mobile phase consisting of 30/70 (v/v %) 10mM ammonium formate, pH3/acetonitrile at a flow rate of 0.3mL/min. Multiple reaction monitoring of the precursor-to-product ion pairs for suvorexant (m/z 451→186) and (13)C(2)H3-suvorexant (m/z 455→190) on an Applied Biosystems API 4000 tandem mass spectrometer was used for quantitation. Intraday assay precision, assessed in six different lots of control plasma, was within 10% CV at all concentrations, while assay accuracy ranged from 95.6 to 105.0% of nominal. Quality control (QC) samples in plasma were stored at -20°C. Initial within day analysis of QCs after one freeze-thaw cycle showed accuracy within 9.5% of nominal with precision (CV) of 6.7% or less. The plasma QC samples were demonstrated to be stable for up to 25 months at -20°C. The method described has been used to support clinical studies during Phase I through III of clinical development.

  10. MALDI-TOF mass spectrometric detection of multiplex single base extended primers

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Sanchez Sanchez, Juan Jose; Børsting, Claus;

    2004-01-01

    One of the most promising techniques for typing of multiple single-nucleotide polymorphism (SNP) is detection of single base extension primers (SBE) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a new MALDI-TOF MS protocol for typing...... triethylamine purification. The biotin-labeled ddNTPs contained linkers with different masses ensuring a clear separation of the alleles even for SBE primers with a mass of 10 300 Da. Furthermore, only 25-350 fmol of SBE primers were necessary in order to obtain reproducible MALDI-TOF spectra. Similar signal......, and the potential use of MALDI-TOF MS for SNP typing is discussed....

  11. Graphite furnace and hydride generation atomic absorption spectrometric determination of cadmium, lead, and tin traces in natural surface waters: study of preconcentration technique performance.

    Science.gov (United States)

    Tsogas, George Z; Giokas, Dimosthenis L; Vlessidis, Athanasios G

    2009-04-30

    In this study three major types of preconcentration methods based upon different principles (cation exchange, physical absorption and hydrophobic extraction) were evaluated and optimized for the extraction and determination of three highly toxic heavy metals namely Cd, Pb and Sn by graphite furnace and hybrid generation atomic absorption spectrometry in real samples. The optimum analytical conditions were examined and the analytical features of each method were revealed and compared. Detection limits as low as 0.003-0.025 microg L(-1) for Cd(2+), 0.05-0.10 microg L(-1) for Pb(2+) and 0.1-0.25 microg L(-1) for Sn(4+) depending on the extraction method were obtained with RSD values between 3.08% and 6.11%. A preliminary assessment of the pollution status of three important natural ecosystems in Epirus region (NW Greece) was performed and some early conclusions were drawn and discussed.

  12. Transient C IV Broad Absorption Lines in radio detected QSOs

    CERN Document Server

    Vivek, M; Gupta, N

    2015-01-01

    We study the transient (i.e. emerging or disappearing) C IV broad absorption line (BAL) components in 50 radio detected QSOs using multi-epoch spectra available in Sloan Digital Sky Survey DR10. We report the detectionof 6 BALQSOs having at least one distinct transient C IV absorption component. Based on the structure function analysis of optical light curves, we suggest that the transient absorption is unlikely to be triggered by continuum variations. Transient absorption components usually have low C IV equivalent widths ( 10000 \\kms) and typically occur over rest-frame timescales > 800 days. The detection rate of transient C IV absorption seen in our sample is higher than that reported in the literature. Using a control sample of QSOs, we show that this difference is most likely due to the longer monitoring time-scale of sources in our sample while the effect of small number statistics cannot be ignored. Thus, in order to establish the role played by radio jets in driving the BAL outflows, we need a larger...

  13. Flame atomic absorption spectrometric determination of trace quantities of cadmium in water samples after cloud point extraction in Triton X-114 without added chelating agents

    Energy Technology Data Exchange (ETDEWEB)

    Afkhami, Abbas [Department of Chemistry, Faculty of Science, Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of)]. E-mail: afkhami@basu.ac.ir; Madrakian, Tayyebeh [Department of Chemistry, Faculty of Science, Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of); Siampour, Hajar [Department of Chemistry, Faculty of Science, Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of)

    2006-11-16

    A new micell-mediated phase separation method for preconcentration of ultra-trace quantities of cadmium as a prior step to its determination by flame atomic absorption spectrometry has been developed. The method is based on the cloud point extraction (CPE) of cadmium in iodide media with Triton X-114 in the absence of any chelating agent. The optimal extraction and reaction conditions (e.g., acid concentration, iodide concentration, effect of time) were studied, and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 3-300 ng mL{sup -1} of cadmium. The detection limit of the method is 1.0 ng mL{sup -1} of cadmium. The interference effect of some anions and cations was also tested. The method was applied to the determination of cadmium in tap water, waste water, and sea water samples.

  14. Selective cloud point extraction and preconcentration of trace amounts of silver as a dithizone complex prior to flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Manzoori, Jamshid L.; Karim-Nezhad, Ghasem

    2003-05-19

    Dithizone (diphenylthiocarbazone) was used as a complexing agent in cloud point extraction for the first time and applied for selective preconcentration of trace amounts of silver. The analyte in the initial aqueous solution was acidified with sulfuric acid (pH<1) and Triton X-114 was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with tetrahydrofuran (THF) and the analyte determined in the enriched solution by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, a preconcentration factor of 43 was obtained for only 10 ml of sample. The analytical curve was linear in the range of 3-200 ng ml{sup -1} and the limit of detection was 0.56 ng ml{sup -1}. The proposed method was applied to the determination of silver in water samples.

  15. Determination of Palladium in Resin by Lead Fire Assaying-Flame Atomic Absorption Spectrometric Method%铅试金富集-火焰原子吸收光谱法测定树脂中钯

    Institute of Scientific and Technical Information of China (English)

    王芳; 陈小兰; 林海山; 李小玲; 肖红新

    2013-01-01

    通过铅试金富集树脂中的钯并用银作钯灰吹保护,得到的银钯合粒用王水溶解,在5%的盐酸介质中,采用原子吸收光谱法测定钯,该法测钯的相对标准偏差RSD为0.53%,加标回收率在99.04%~100.10%之间。%Palladium in resin was enriched by lead assaying, using silver as a protective agent to produce silver-palladium alloy, and then the alloy was dissolved in aqua regia. Air acetylene flame atomic absorption spectrometric method was used to determinate palladium in 5%hydrochloric acid solution. The relative standard deviation (RSD) in determination of palladium is 0.53%and the recovery rate is between 99.04%~100.10%.

  16. Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A., E-mail: joseph.caruso@uc.edu; Landero-Figueroa, Julio

    2014-10-01

    The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag{sup +}) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg{sup −1} detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

  17. Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

    Science.gov (United States)

    Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A.; Landero-Figueroa, Julio

    2014-10-01

    The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV-VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag+) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg- 1 detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

  18. Detecting Ultralight Bosonic Dark Matter via Absorption in Superconductors

    CERN Document Server

    Hochberg, Yonit; Zurek, Kathryn M

    2016-01-01

    Superconducting targets have recently been proposed for the direct detection of dark matter as light as a keV, via elastic scattering off conduction electrons in Cooper pairs. Detecting such light dark matter requires sensitivity to energies as small as the superconducting gap of O(meV). Here we show that these same superconducting devices can detect much lighter DM, of meV to eV mass, via dark matter absorption on a conduction electron, followed by emission of an athermal phonon. We demonstrate the power of this setup for relic kinetically mixed hidden photons, pseudoscalars, and scalars, showing the reach can exceed current astrophysical and terrestrial constraints with only a moderate exposure.

  19. Are cold flows detectable with metal absorption lines?

    CERN Document Server

    Kimm, Taysun; Devriendt, Julien; Pichon, Christophe

    2010-01-01

    [Abridged] Cold gas flowing within the "cosmic web" is believed to be an important source of fuel for star formation at high redshift. However, the presence of such filamentary gas has never been observationally confirmed. In this work, we investigate in detail whether such cold gas is detectable using low-ionisation metal absorption lines, such as CII \\lambda1334 as this technique has a proven observational record for detecting gaseous structures. Using a large statistical sample of galaxies from the Mare Nostrum N-body+AMR cosmological simulation, we find that the typical covering fraction of the dense, cold gas in 10^12 Msun haloes at z~2.5 is lower than expected (~5%). In addition, the absorption signal by the interstellar medium of the galaxy itself turns out to be so deep and so broad in velocity space that it completely drowns that of the filamentary gas. A detectable signal might be obtained from a cold filament exactly aligned with the line of sight, but this configuration is so unlikely that it woul...

  20. Are cold flows detectable with metal absorption lines?

    Science.gov (United States)

    Kimm, Taysun; Slyz, Adrianne; Devriendt, Julien; Pichon, Christophe

    2011-05-01

    Cosmological simulations have shown that dark matter haloes are connected to each other by large-scale filamentary structures. Cold gas flowing within this ‘cosmic web’ is believed to be an important source of fuel for star formation at high redshift. However, the presence of such filamentary gas has never been observationally confirmed despite the fact that its covering fraction within massive haloes at high redshift is predicted to be significant (˜25 per cent). In this Letter, we investigate in detail whether such cold gas is detectable using low-ionization metal absorption lines, such as C IIλ1334, as this technique has a proven observational record for detecting gaseous structures. Using a large statistical sample of galaxies from the MARENOSTRUM N-body+ adaptive mesh refinement (AMR) cosmological simulation, we find that the typical covering fraction of the dense, cold gas in 1012 M⊙ haloes at z˜ 2.5 is lower than expected (˜5 per cent). In addition, the absorption signal by the interstellar medium of the galaxy itself turns out to be so deep and so broad in velocity space that it completely drowns that of the filamentary gas. A detectable signal might be obtained from a cold filament exactly aligned with the line of sight, but this configuration is so unlikely that it would require surveying an overwhelmingly large number of candidate galaxies to tease it out. Finally, the predicted metallicity of the cold gas in filaments is extremely low (≤10-3 Z⊙). If this result persists when higher resolution runs are performed, it would significantly increase the difficulty of detecting filamentary gas inflows using metal lines. However, even if we assume that filaments are enriched to Z⊙, the absorption signal that we compute is still weak. We are therefore led to conclude that it is extremely difficult to observationally prove or disprove the presence of cold filaments as the favourite accretion mode of galaxies using low-ionization metal absorption

  1. Column preconcentration of gold by adsorbing AuCl4- onto methyltrioctyl ammonium chloride-naphthalene and subsequent atomic absorption spectrometric determination.

    Science.gov (United States)

    Behpour, M; Attaran, A M; Ghoreishi, S M; Soltani, N

    2005-05-01

    A sensitive, selective and simple preconcentration method for ultra-trace gold determination has been developed that uses naphthalene-methyltrioctyl ammonium chloride (Aliquat 336s) as an adsorbent. Gold, in the form of AuCl4-, was retained by the adsorbent in the column at a flow rate of 1 ml min(-1). After filtration, the solid mass consisting of the gold complex and naphthalene was dissolved out of the column with 5 ml of N,N-dimethylformamide (DMF), and the metal was then determined by atomic absorption spectrometry. In the initial solution, the calibration graph of absorbance versus gold concentration was found to be linear in the range 0.5-150 ng ml(-1) Au(III) with r=0.997 (n=9), and the 3 s detection limit was 0.428 ng ml(-1). The relative standard deviation for eight replicate measurements of 20 microg of gold was 2.14%. Preconcentration factors of 390 and 650 were achieved using 5 ml and 3 ml of DMF, respectively. The proposed method was successfully applied to the determination of gold in wastewater, processed pool water, slurry pool water, and raw well-water from the Moteh gold mine, and synthetic samples.

  2. The study of applicability of dithiocarbamate-coated fullerene C 60 for preconcentration of palladium for graphite furnace atomic absorption spectrometric determination in environmental samples

    Science.gov (United States)

    Leśniewska, Barbara A.; Godlewska, Iwona; Godlewska—Żyłkiewicz, Beata

    2005-03-01

    The present method comprises an off-line enrichment of Pd on the fullerene, C 60, coated with ammonium pyrrolidinedithiocarbamate (APDC), followed by the elution of formed Pd-chelate with ethanol and the subsequent determination of Pd from the eluate by graphite furnace atomic absorption spectrometry. By using fullerene loaded with 0.1% APDC, the analytical system is simplified as the sample can be directly preconcentrated on the column. The following parameters affecting the preconcentration of Pd on C 60 were optimized: amount of ligand used for the coating of fullerene, sample pH, kind of eluent, sample and eluent flow rates, volume and number of fractions of eluent used. The sorption efficiency for Pd on coated fullerene was 99.2±1.1%. The best elution efficiency for Pd from the column was obtained with 0.6 ml of ethanol at a flow rate of 0.2 ml min -1. The limit of detection was 0.044 ng ml -1. The effect of sample pretreatment procedure on the preconcentration of Pd by evaluated method is discussed. The content of Pd in road dust (179.2±17.4 ng g -1) determined by proposed method was in agreement with the results obtained with a reference method. The low recovery of analyte (64%) was obtained for geological material CRM SARM-7 (platinum ore) due to the much higher concentration of interfering elements.

  3. The study of applicability of dithiocarbamate-coated fullerene C{sub 60} for preconcentration of palladium for graphite furnace atomic absorption spectrometric determination in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Lesniewska, Barbara A. [Institute of Chemistry, University of BiaIystok, Hurtowa 1, 15-399 BiaIystok (Poland); Godlewska, Iwona [Institute of Chemistry, University of BiaIystok, Hurtowa 1, 15-399 BiaIystok (Poland); GodlewskayIkiewicz, Beata [Institute of Chemistry, University of BiaIystok, Hurtowa 1, 15-399 BiaIystok (Poland)]. E-mail: bgodlew@uwb.edu.pl

    2005-03-31

    The present method comprises an off-line enrichment of Pd on the fullerene, C{sub 60}, coated with ammonium pyrrolidinedithiocarbamate (APDC), followed by the elution of formed Pd-chelate with ethanol and the subsequent determination of Pd from the eluate by graphite furnace atomic absorption spectrometry. By using fullerene loaded with 0.1% APDC, the analytical system is simplified as the sample can be directly preconcentrated on the column. The following parameters affecting the preconcentration of Pd on C{sub 60} were optimized: amount of ligand used for the coating of fullerene, sample pH, kind of eluent, sample and eluent flow rates, volume and number of fractions of eluent used. The sorption efficiency for Pd on coated fullerene was 99.2{+-}1.1%. The best elution efficiency for Pd from the column was obtained with 0.6 ml of ethanol at a flow rate of 0.2 ml min{sup -1}. The limit of detection was 0.044 ng ml{sup -1}. The effect of sample pretreatment procedure on the preconcentration of Pd by evaluated method is discussed. The content of Pd in road dust (179.2{+-}17.4 ng g{sup -1}) determined by proposed method was in agreement with the results obtained with a reference method. The low recovery of analyte (64%) was obtained for geological material CRM SARM-7 (platinum ore) due to the much higher concentration of interfering elements.

  4. Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

    Science.gov (United States)

    Tuzen, Mustafa; Pekiner, Ozlem Zeynep

    2015-12-01

    A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium.

  5. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Ghaedi, Mehrorang, E-mail: m_ghaedi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Shokrollahi, Ardeshir [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Niknam, Khodabakhsh [Chemistry Department, Persian Gulf University, Bushehr (Iran, Islamic Republic of); Niknam, Ebrahim; Najibi, Asma [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Soylak, Mustafa [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

    2009-09-15

    The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1 mol L{sup -1} HNO{sub 3} was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL{sup -1} for Cd{sup 2+}, Pb{sup 2+}, Pd{sup 2+} and Ag{sup +} along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd{sup 2+}, Pb{sup 2+}, Pd{sup 2+} and Ag{sup +}, respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

  6. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples.

    Science.gov (United States)

    Ghaedi, Mehrorang; Shokrollahi, Ardeshir; Niknam, Khodabakhsh; Niknam, Ebrahim; Najibi, Asma; Soylak, Mustafa

    2009-09-15

    The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1molL(-1) HNO(3) was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL(-1) for Cd(2+), Pb(2+), Pd(2+) and Ag(+) along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd(2+), Pb(2+), Pd(2+) and Ag(+), respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

  7. Use of sodium tungstate as a permanent chemical modifier for slurry sampling electrothermal atomic absorption spectrometric determination of indium in soils

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Garcia, Ignacio; Rivas, Ricardo E.; Hernandez-Cordoba, Manuel [University of Murcia, Department of Analytical Chemistry, Faculty of Chemistry, Murcia (Spain)

    2008-06-15

    A number of chemical modifiers have been assessed for the direct determination of indium in soils using electrothermal atomic absorption spectrometry and slurry sampling. The best results were obtained when the graphite atomizer was impregnated with sodium tungstate, which acts as a permanent chemical modifier. Slurries were prepared by suspending 100 mg sample in a solution containing 1% (v/v) concentrated nitric acid and 10% (v/v) concentrated hydrofluoric acid and then 15-{mu}L aliquots were directly introduced into the atomizer. Standard indium solutions prepared in the suspension medium in the range 4-80 {mu}g L{sup -1} indium were used for calibration. The relative standard deviation for ten consecutive measurements of a 40 {mu}g L{sup -1} indium solution was 2.8%. The limit of detection in soils was 0.1 {mu}g g{sup -1}. The reliability of the procedures was confirmed by analysing two standard reference materials and by using an alternative procedure. (orig.)

  8. Stable isotope dilution analysis of salicylic acid and hydroquinone in human skin samples by gas chromatography with mass spectrometric detection.

    Science.gov (United States)

    Judefeind, Anja; van Rensburg, Peet Jansen; Langelaar, Stephan; du Plessis, Jeanetta

    2007-06-01

    A sensitive and accurate gas chromatographic-mass spectrometric (GC-MS) method has been developed for the quantitative determination of salicylic acid (SA) and hydroquinone (HQ) from human skin samples and cosmetic emulsions. Deuterium labeled SA-d(6) and HQ-d(6) were used as internal standards (IS). The samples were extracted with methanol, dried under nitrogen and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS). Quantification was performed in SIM mode with a limit of quantification (LOQ) of 50 ng ml(-1) for SA and 10 ng ml(-1) for HQ. The inter-day variation (R.S.D.) was less than 5% and the accuracy was better than 13.3% for both compounds. The recoveries from the different matrices ranged between 93.1 and 103.3% for SA, and 97.3 and 100.8% for HQ.

  9. Visual and light scattering spectrometric method for the detection of melamine using uracil 5‧-triphosphate sodium modified gold nanoparticles

    Science.gov (United States)

    Liang, Lijiao; Zhen, Shujun; Huang, Chengzhi

    2017-02-01

    A highly selective method was presented for colorimetric determination of melamine using uracil 5‧-triphosphate sodium modified gold nanoparticles (UTP-Au NPs) in this paper. Specific hydrogen-bonding interaction between uracil base (U) and melamine resulted in the aggregation of AuNPs, displaying variations of localized surface plasmon resonance (LSPR) features such as color change from red to blue and enhanced localized surface plasmon resonance light scattering (LSPR-LS) signals. Accordingly, the concentration of melamine could be quantified based on naked eye or a spectrometric method. This method was simple, inexpensive, environmental friendly and highly selective, which has been successfully used for the detection of melamine in pretreated liquid milk products with high recoveries.

  10. Evaluation of capillary supercritical fluid chromatography with mass spectrometric detection for the analysis of a drug (mebeverine) in a dog plasma matrix.

    Science.gov (United States)

    Pinkston, J D; Venkatramani, C J; Tulich, L J; Bowling, D J; Wehmeyer, K R

    1993-12-22

    Supercritical fluid chromatography with mass spectrometric detection was evaluated as a technique for the analysis of drugs in biological fluids. Dog plasma was spiked with a model drug, mebeverine, and with a deuterium-labeled analog of mebeverine. The spiked plasma was prepared for analysis by solid-phase extraction on octadecylsilane cartridges. Mebeverine levels in the spiked dog plasma samples were determined by interpolation from a standard curve. Accuracy and precision of the analysis were determined within and between days. In general, accuracy was found to be 100 +/- 15% for plasma samples spiked with 6 to 60 ng mebeverine/ml. The relative standard deviation for replicate sample analysis over this concentration range was between 5 and 12.5%.

  11. Novel analytical reagent for the application of cloud-point preconcentration and flame atomic absorption spectrometric determination of nickel in natural water samples

    Energy Technology Data Exchange (ETDEWEB)

    Suvardhan, K. [Environmental Monitoring Laboratory, Department of Chemistry, S.V. University, AP (India); Rekha, D. [Environmental Monitoring Laboratory, Department of Chemistry, S.V. University, AP (India); Kumar, K. Suresh [Environmental Monitoring Laboratory, Department of Chemistry, S.V. University, AP (India); Prasad, P. Reddy [Environmental Monitoring Laboratory, Department of Chemistry, S.V. University, AP (India); Kumar, J. Dilip [Environmental Monitoring Laboratory, Department of Chemistry, S.V. University, AP (India); Jayaraj, B. [Department of Mathematics, S.V. University, Tirupati 517502, AP (India); Chiranjeevi, P. [Environmental Monitoring Laboratory, Department of Chemistry, S.V. University, AP (India)]. E-mail: chiranjeevipattium@gmail.com

    2007-06-01

    Cloud-point extraction was applied as a preconcentration of nickel after formation of complex with newly synthesized N-quino[8,7-b]azin-5-yl-2,3,5,6,8,9,11,12octahydrobenzo[b][1,4,7,10,13] pentaoxacyclopentadecin-15-yl-methanimine, and later determined by flame atomic absorption spectrometry (FAAS) using octyl phenoxy polyethoxy ethanol (Triton X-114) as surfactant. Nickel was complexed with N-quino[8,7-b]azin-5-yl-2,3,5,6,8,9,11,12 octahydrobenzo[b][1,4,7,10,13]pentaoxacyclopentadecin-15-yl-methanimine in an aqueous phase and was kept for 15 min in a thermo-stated bath at 40 deg. C. Separation of the two phases was accomplished by centrifugation for 15 min at 4000 rpm. The chemical variables affecting the cloud-point extraction were evaluated, optimized and successfully applied to the nickel determination in various water samples. Under the optimized conditions, the preconcentration system of 100 ml sample permitted an enhancement factor of 50-fold. The detailed study of various interferences made the method more selective. The detection limits obtained under optimal condition was 0.042 ng ml{sup -1}. The extraction efficiency was investigated at different nickel concentrations (20-80 ng ml{sup -1}) and good recoveries (99.05-99.93%) were obtained using present method. The proposed method has been applied successfully for the determination of nickel in various water samples and compared with reported method in terms of Student's t-test and variance ratio f-test which indicate the significance of present method over reported and spectrophotometric methods at 95% confidence 0011lev.

  12. On-line sequential injection dispersive liquid-liquid microextraction system for flame atomic absorption spectrometric determination of copper and lead in water samples.

    Science.gov (United States)

    Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

    2009-06-30

    A simple, sensitive and powerful on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system was developed as an alternative approach for on-line metal preconcentration and separation, using extraction solvent at microlitre volume. The potentials of this novel schema, coupled to flame atomic absorption spectrometry (FAAS), were demonstrated for trace copper and lead determination in water samples. The stream of methanol (disperser solvent) containing 2.0% (v/v) xylene (extraction solvent) and 0.3% (m/v) ammonium diethyldithiophosphate (chelating agent) was merged on-line with the stream of sample (aqueous phase), resulting a cloudy mixture, which was consisted of fine droplets of the extraction solvent dispersed entirely into the aqueous phase. By this continuous process, metal chelating complexes were formed and extracted into the fine droplets of the extraction solvent. The hydrophobic droplets of organic phase were retained into a microcolumn packed with PTFE-turnings. A portion of 300 microL isobutylmethylketone was used for quantitative elution of the analytes, which transported directly to the nebulizer of FAAS. All the critical parameters of the system such as type of extraction solvent, flow-rate of disperser and sample, extraction time as well as the chemical parameters were studied. Under the optimum conditions the enhancement factor for copper and lead was 560 and 265, respectively. For copper, the detection limit and the precision (R.S.D.) were 0.04 microg L(-1) and 2.1% at 2.0 microg L(-1) Cu(II), respectively, while for lead were 0.54 microg L(-1) and 1.9% at 30.0 microg L(-1) Pb(II), respectively. The developed method was evaluated by analyzing certified reference material and applied successfully to the analysis of environmental water samples.

  13. Searching for Dark Absorption with Direct Detection Experiments

    CERN Document Server

    Bloch, Itay M; Tobioka, Kohsaku; Volansky, Tomer; Yu, Tien-Tien

    2016-01-01

    We consider the absorption by bound electrons of dark matter in the form of dark photons and axion-like particles, as well as of dark photons from the Sun, in current and next-generation direct detection experiments. Experiments sensitive to electron recoils can detect such particles with masses between a few eV to more than 10 keV. For dark photon dark matter, we update a previous bound based on XENON10 data and derive new bounds based on data from XENON100 and CDMSlite. We find these experiments to disfavor previously allowed parameter space. Moreover, we derive sensitivity projections for SuperCDMS at SNOLAB for silicon and germanium targets, as well as for various possible experiments with scintillating targets (cesium iodide, sodium iodide, and gallium arsenide). The projected sensitivity can probe large new regions of parameter space. For axion-like particles, the same current direction detection data improves on previously known direct-detection constraints but does not bound new parameter space beyond...

  14. Application of comprehensive two-dimensional gas chromatography with mass spectrometric detection for the analysis of selected drug residues in wastewater and surface water

    Institute of Scientific and Technical Information of China (English)

    Petr Lacina; Ludmila Mravcová; Milada Vávrová

    2013-01-01

    Pharmaceutical residues have become tightly controlled environmental contaminants in recent years,due to their increasing concentration in environmental components.This is mainly caused by their high level of production and everyday consumption.Therefore there is a need to apply new and sufficiently sensitive analytical methods,which can detect the presence of these contaminants even in very low concentrations.This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues,mainly from the group of non-steroidal anti-iaffammatory drugs (salicylic acid,acetylsalicylic acid,clofibric acid,ibuprofen,acetaminophen,caffeine,naproxen,mefenamic acid,ketoprofen,and dicofenac),in wastewaters and surface waters.This analytical method is based on solid phase extraction,derivatization by N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection (GCxGC-TOF MS).Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix.The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice,Czech Republic.The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of μg/L in wastewater.

  15. Simple and sensitive determination of o-phenylphenol in citrus fruits using gas chromatography with atomic emission or mass spectrometric detection.

    Science.gov (United States)

    Kolbe, Nina; Andersson, Jan T

    2006-08-09

    In this work, a simple and sensitive method for the analysis of the pesticide o-phenylphenol (OPP) on citrus fruits was developed. OPP is extracted with dichloromethane by ultrasonication and derivatized with ferrocenecarboxylic acid chloride. Using ferrocene as a label, residues of OPP are determined by gas chromatography with atomic emission detection in the iron selective mode or with mass spectrometric detection. Sample cleanup is simple and rapid and merely involves a removal of excess reagent on an alumina minicolumn. The method detection limit is 2 ng of OPP/g of fruit, and recoveries from lemon samples fortified at levels of 35 and 140 ng/g are 101 and 106%, respectively. The citrus fruits analyzed (oranges, grapefruits, lemons) contained between 60 ng/g and 0.37 microg/g OPP (RSD = 8-13%), and the results were in good agreement with results obtained when OPP was analyzed using an established HPLC-FLD method. Several alcohols could also be identified in the fruit peel.

  16. Spectrometric techniques 4

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume IV discusses three widely diversified areas of spectrometric techniques. The book focuses on three spectrometric methods. Chapter 1 discusses the phenomenology and applications of Coherent Anti-Stokes Raman Spectroscopy (CARS), the most commonly used optical technique that exploit the Raman effect. The second chapter is concerned with diffraction gratings and mountings for the Vacuum Ultraviolet Spectral Region. Chapter 3 accounts the uses of mass spectrometry, detectors, types of spectrometers, and ion sources. Physicists and chemists will find the book a go

  17. HAB detection based on absorption and backscattering properties of phytoplankton

    Science.gov (United States)

    Lei, Hui; Pan, Delu; Bai, Yan; Chen, Xiaoyan; Zhou, Yan; Zhu, Qiankun

    2011-11-01

    The coastal area of East China Sea (ECS) suffers from the harmful algal blooms (HAB) frequently every year in the warm season. The most common causative phytoplankton algal species of HAB in the ECS in recent years are Prorocentrum donghaiense (dinoflagellates), Karenia mikimotoi (dinoflagellates which could produce hemolytic and ichthyotoxins) and Skeletonema costatum (diatom). The discrimination between the dinoflagellates and diatom HAB through ocean color remote sensing approach can add the knowledge of HAB events in ECS and help to the precaution. A series of in-situ measurement consisted of absorption coefficient, total scattering and particulate backscattering coefficient was conducted in the southern coast of Zhejiang Province in May 2009, and the estuary of Changjiang River in August 2009 and December 2010, which encountered two HAB events and a moderate bloom. The Inherent Optical Properties (IOPs) of the bloom waters have significant difference between phytoplankton species in absorption and backscattering properties. The chlorophyll a specific absorption coefficient (a*phy(λ)) for the bloom patches (chlorophyll a concentration >6mg m-3) differ greatly from the adjacent normal seawater, with the a*phy(λ) of bloom water lower than 0.03 m2 mg-1 while the a*phy(λ) of the adjacent normal seawater is much higher (even up to 0.06 m2 mg-1). Meanwhile, the backscattering coefficients at 6 wavebands (420, 442, 470, 510, 590 and 700nm) are also remarkably lower for bloom waters ( 0.02 m-1). The backscattering coefficient ratio (Rbp(λ)) is much lower for diatom bloom waters than for dinoflagellates types (0.01079 vs. 0.01227). A discrimination model based on IOPs is established, and several typical dinoflagellates and diatom bloom events including Prorocentrum donghaiense, Karenia mikimotoi and Skeletonema costatum in the ECS are picked out for testing with the MODIS-L2 and L3 ocean color remote sensing products from NASA website. The result proves that the

  18. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, S. [Bundeskriminalamt (BKA), Forensic Science Institute KT23, Thaerstr. 11, D - 65193 Wiesbaden (Germany); Otto, M. [TU Bergakademie Freiberg (TU BAF), Institute for Analytical Chemistry, Leipziger Str. 29, D - 09599 Freiberg (Germany)], E-mail: matthias.otto@chemie.tu-freiberg.de; Niewoehner, L.; Barth, M. [Bundeskriminalamt (BKA), Forensic Science Institute KT23, Thaerstr. 11, D - 65193 Wiesbaden (Germany); Brozek-Mucha, Z. [Instytut Ekspertyz Sadowych (IES), Westerplatte St. 9, PL - 31-033 Krakow (Poland); Biegstraaten, J. [Nederlands Forensisch Instituut (NFI), Fysische Technologie, Laan van Ypenburg 6, NL-2497 GB Den Haag (Netherlands); Horvath, R. [Kriminalisticky a Expertizny Ustav (KEU PZ), Institute of Forensic Science, Sklabinska 1, SK - 812 72 Bratislava (Slovakia)

    2007-09-15

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

  19. Identification of Polish cochineal (Porphyrophora polonica L.) in historical textiles by high-performance liquid chromatography coupled with spectrophotometric and tandem mass spectrometric detection.

    Science.gov (United States)

    Lech, Katarzyna; Jarosz, Maciej

    2016-05-01

    The present work reports a method for identification of Polish cochineal (Porphyrophora polonica L.) in historical fabrics by the use of high-performance liquid chromatography coupled with diode array and tandem mass spectrometric detection with electrospray ionization (HPLC-DAD-ESI MS/MS). This hyphened technique allows detection and identification of 16 new minor colorants present in the discussed scale insect (including two previously observed by Wouters and Verhecken (Ann Soc Entomol Fr. 1989;25:393-410), but specified only as compounds of unknown structures) that do not occur (e.g., in American cochineal). The MS/MS experiments, complemented with UV-VIS data, enable identification of mono- and di-, C- and O-hexosides of kermesic and flavokermesic acids or their derivatives. The present paper introduces a fingerprint of color compounds present in Polish cochineal and defines them, particularly pp6 (ppI, O-hexoside of flavokermesic acid), as its markers allow distinguishing of Polish-cochineal reds from the American ones. Usefulness of the selected set of markers for identification of Polish cochineal has been demonstrated in the examination of textiles from the collection of the National Museum in Warsaw using the multiple reaction monitoring (MRM) method, originally elaborated on the basis of this study.

  20. A method of test for residual isophorone diisocyanate trimer in new polyester-polyurethane coatings on light metal packaging using liquid chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Driffield, Malcolm; Bradley, Emma L; Castle, Laurence

    2007-02-02

    A method of test for residual isophorone diisocyanate (IPDI) trimer in experimental formulation polyester-polyurethane (PEPU) thermoset coatings on metal food packaging is described. The method involves extraction of coated panels using acetonitrile containing dibutylamine for concurrent derivatisation, and then high performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection (LC-MS/MS). Single laboratory validation was carried out using three different experimental PEPU-based coatings. The calibrations were linear, the analytical recovery was good, no interferences were seen, and substance identification criteria were met. The detection limit of the method is around 0.02 micro g/100 cm(2) of coating, which for a typical sized can and assuming complete migration of any residual IPDI trimer, corresponds to about 0.2 micro g/kg food or beverage. Separate studies indicated that, even if migration occurred at such low levels, the IPDI trimer would not be expected to persist in canned aqueous or fatty foodstuffs as it would hydrolyse to the corresponding aliphatic amine or react with food components to destroy the isocyanate moiety. The method of test developed here for residual IPDI trimer in thermoset polyester-polyurethane coatings should prove to be a valuable tool for investigating the cure kinetics of these novel coatings and help to guide the development of enhanced formulations.

  1. Quantification of ultra-trace amounts of copper by using off-line solid phase extraction-flame atomic absorption spectrometric determination through the octadecyl silica-bonded phase membrane (OSPM) C18 disks impregnated with 2,2'-[ethane-1,2-diylbis(thio)]dianiline.

    Science.gov (United States)

    Mohammadhosseini, Majid; Soliemani, Esmaeil

    2014-07-01

    This study reports a very selective, easy, and precise method for rapid separation of trace amounts of copper in aqueous samples using octadecyl silica-bonded phase membrane disks modified by 2,2'-[ethane-1,2-diylbis(thio)]dianiline (EDTD) combined with flame atomic absorption spectrometric determination. In addition, the synthesis and spectral characterization of EDTD have been described in detail. All the affecting experimental variables such as pH, amount of modifier, eluent type, sample and eluent flow rate, interfering ions, and disk capacity were also investigated. The target analyte (trace copper) was quantitatively retained at pH = 4 and eluted with 6.0 mL of 0.5 M HNO3 at flow rates of 40 and 10 mL min−1 for analyte passage and elution steps, respectively, through the disks modified with 17.0 mg of EDTD. The proposed method also allows an enrichment factor of about 500 and has a detection limit of 0.005 ng mL−1. The method has been successfully applied for isolation and determination of copper in different water samples, peppers, and standard alloys.

  2. Validation of method for determination of different classes of pesticides in aqueous samples by dispersive liquid-liquid microextraction with liquid chromatography-tandem mass spectrometric detection.

    Science.gov (United States)

    Caldas, Sergiane Souza; Costa, Fabiane Pinho; Primel, Ednei Gilberto

    2010-04-14

    In this study, a simple, rapid and efficient method has been developed for the extraction and preconcentration of different classes of pesticides, carbofuran (insecticide), clomazone (herbicide) and tebuconazole (fungicide) in aqueous samples by dispersive liquid-liquid microextraction (DLLME) coupled with liquid chromatography-tandem mass spectrometric detection. Some experimental parameters that influence the extraction efficiency, such as the type and volume of the disperser solvents and extraction solvents, extraction time, speed of centrifugation, pH and addition of salt were examined and optimized. Under the optimum conditions, the recoveries of pesticides in water at spiking levels between 0.02 and 2.0 microg L(-1) ranged from 62.7% to 120.0%. The relative standard deviations varied between 1.9% and 9.1% (n=3). The limits of quantification of the method considering a 50-fold preconcentration step were 0.02 microg L(-1). The linearity of the method ranged from 1.0 to 1000 microg L(-1) for all compounds, with correlation coefficients varying from 0.9982 to 0.9992. Results show that the method we propose can meet the requirements for the determination of pesticides in water samples. The comparison of this method with solid-phase extraction indicates that DLLME is a simple, fast, and low-cost method for the determination of pesticides in natural waters.

  3. Carbon-enhanced inductively coupled plasma mass spectrometric detection of arsenic and selenium and its application to arsenic speciation

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Sturup, Stefan

    1994-01-01

    /nebulization efficiency. It is proposed that an increased population of carbon ions or carbon-containing ions in the plasma facilitates a more complete ionization of analytes lower in ionization energy than carbon itself. The enhanced detection power for arsenic was applied to arsenic speciation by high-performance...... liquid chromatography (HPLC)-ICP-MS, and made possible the detection of the arsenocholine ion (AsC) in extracts of shrimp at the 5-10 ng g-1 concentration level. The limit of detection was improved by a factor of 3.4 after addition of methanol and was 4.7 ng g-1 as the AsC ion....

  4. A multiresidue liquid chromatographic/tandem mass spectrometric method for the detection and quantitation of 15 nonsteroidal anti-inflammatory drugs (NSAIDs) in bovine meat and milk.

    Science.gov (United States)

    van Pamel, Els; Daeseleire, Els

    2015-06-01

    This study concerns a validated liquid chromatographic/tandem mass spectrometric (LC-MS/MS) multiresidue method for the simultaneous detection, identification, and quantitation of 15 nonsteroidal anti-inflammatory drugs (NSAIDs) in bovine meat and milk. The NSAIDs considered are carprofen, diclofenac, flufenamic acid, flunixin (5-hydroxyflunixin as marker metabolite in milk), ketoprofen, mefenamic acid, meloxicam, 4-methylaminoantipyrine (marker metabolite of metamizole in meat and milk), naproxen, niflumic acid, phenylbutazone (and metabolite oxyphenbutazone), ramifenazone, salicylic acid, and tolfenamic acid. These compounds were chosen as representatives of different chemical subclasses of NSAIDs. Flunixin-d3, diclofenac-d4, 4-aminoantipyrine-d3, and phenylbutazone-d10 were used as internal standards. Performance characteristics were validated according to the Commission Decision 2002/657/EC (Off J Eur Communities, L221: 8-36). Recovery percentages varied between 81 and 114% for bovine meat and between 79 and 118% for milk. Repeatability percentages were within the range of 1-12% for meat and between 1 and 17% for milk, whereas the intralaboratory reproducibility varied between 3 and 19% for meat and between 3 and 23% for milk. The decision limit and the detection capability for bovine meat were within the range of 0.5-579 μg kg(-1)and 0.6-642 μg kg(-1), respectively. Those for milk were within the range of 0.12-55 μg kg(-1) and 0.14-61 μg kg(-1), respectively. The methods developed were successfully applied for proficiency test samples and routine samples analyzed in the laboratory. The methodology concerns fast, user-friendly, and sensitive methods, which can be easily extended for other compounds and matrices. In general, such multiresidue methods contribute to the reduction of human exposure to these veterinary drug residues by consumption of contaminated bovine-derived products such as meat and milk.

  5. Characterization of therapeutic antibodies and related products by two-dimensional liquid chromatography coupled with UV absorbance and mass spectrometric detection.

    Science.gov (United States)

    Stoll, Dwight; Danforth, John; Zhang, Kelly; Beck, Alain

    2016-10-01

    The development of analytical tools for the characterization of large biomolecules is an emerging and rapidly evolving area. This development activity is motivated largely by the current trend involving the increase in development and use of large biomolecules for therapeutic uses. Given the inherent complexity of these biomolecules, which arises from their sheer size and possibilities for chemical modification as well as changes over time (e.g., through modification in solution, aggregation), two-dimensional liquid chromatography (2D-LC) has attracted considerable interest as an analytical tool to address the challenges faced in characterizing these materials. The immediate potential benefits of 2D-LC over conventional one-dimensional liquid chromatography in this context include: (1) higher overall resolving power; (2) complementary information gained from two dimensions of separation in a single analysis; and (3) enabling indirect coupling of separation modes that are inherently incompatible with mass spectrometric (MS) detection (e.g., ion-exchange, because of high-salt eluents) to MS through a more compatible second dimension separation such as reversed-phase LC. In this review we summarize the work in this area, most of which has occurred in the past five years. Although the future is bright for further development in this area, some challenges have already been addressed through new 2D-LC methods. These include: (1) deep characterization of monoclonal antibodies to understand charge heterogeneity, glycosylation patterns, and other modifications; (2) characterization of antibody-drug conjugates to understand the extent and localization of small molecule conjugation; (3) detailed study of excipients in protein drug formulations; and (4) detection of host-cell proteins on biotherapeutic molecule preparations. We fully expect that in the near future we will see this list expanded, and that continued development will lead to methods with further improved

  6. Valence-to-core-detected X-ray absorption spectroscopy

    DEFF Research Database (Denmark)

    Hall, Eleanor R.; Pollock, Christopher J.; Bendix, Jesper;

    2014-01-01

    X-ray absorption spectroscopy (XAS) can provide detailed insight into the electronic and geometric structures of transition-metal active sites in metalloproteins and chemical catalysts. However, standard XAS spectra inherently represent an average contribution from the entire coordination...

  7. On-line two-dimensional capillary electrophoresis with mass spectrometric detection using a fully electric isolated mechanical valve.

    Science.gov (United States)

    Kohl, Felix J; Montealegre, Cristina; Neusüß, Christian

    2016-04-01

    CE is becoming more and more important in many fields of bioanalytical chemistry. Besides optical detection, hyphenation to ESI-MS detection is increasingly applied for sensitive identification purposes. Unfortunately, many CE techniques and methods established in research and industry are not compatible to ESI-MS since essential components of the background electrolyte interfere in ES ionization. In order to identify unknown peaks in established CE methods, here, a heart-cut 2D-CE separation system is introduced using a fully isolated mechanical valve with an internal loop of only 20 nL. In this system, the sample is separated using potentially any non-ESI compatible method in the first separation dimension. Subsequently, the portion of interest is cut by the internal sample loop of the valve and reintroduced to the second dimension where the interfering compounds are removed, followed by ESI-MS detection. When comparing the separation efficiency of the system with the valve to a system using a continuous capillary only a slight increase in peak width is observed. Ultraviolet/visible detection is integrated in the first dimension for switching time determination, enabling reproducible cutting of peaks of interest. The feasibility of the system is successfully demonstrated by a 2D analysis of a BSA tryptic digest sample using a nonvolatile (phosphate based) background electrolyte in the first dimension.

  8. Detection of human butyrylcholinesterase-nerve gas adducts by liquid chromatography-mass spectrometric analysis after in gel chymotryptic digestion.

    Science.gov (United States)

    Tsuge, Kouichiro; Seto, Yasuo

    2006-06-21

    To verify the exposure to nerve gas, a method for detecting human butyrylcholinesterase (BuChE)-nerve gas adduct was developed using LC-electrospray mass spectrometry (ESI-MS). Purified human serum BuChE was incubated with sarin, soman or VX, and the adduct was purified by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and digested in gel by treatment with chymotrypsin. The resulting peptide mixture was subjected to LC-ESI-MS. From the chymotryptic digest of untreated human BuChE, one peak corresponding to the peptide fragment containing the active center serine residue was detected on the extracted ion chromatogram at m/z 948.5, and the sequence was ascertained to be "GESAGAASVSL" by MS/MS analysis. From the chymotryptic digest of the human BuChE-sarin adduct, a singly charged peptide peak was detected on the extracted ion chromatogram at m/z 1,069.5, and the sequence was ascertained to be "GEXAGAASVSL" by MS/MS analysis (X denotes isopropylmethylphosphonylated serine). The difference in molecular weight (120.0 Da) between the active center peptide fragments corresponding to the untreated BuChE and BuChE-sarin adduct was assumed to be derived from the addition of an isopropyl methylphosphonyl moiety to the serine residue. The formation of human BuChE adducts with soman, VX and an aged soman adduct was confirmed by detecting the respective active center peptide fragments using LC-ESI-MS. To apply the established method to an actual biological sample, human serum was incubated with VX, and the adduct was purified by procainamide affinity chromatography followed by SDS-PAGE. After chymotryptic in gel digestion, the ethylphosphonylated active center peptide fragment could be detected, and the structure of the residue was ascertained by LC-ESI-MS analysis.

  9. Spectrometric techniques 3

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume III presents the applications of spectrometric techniques to atmospheric and space studies. This book reviews the spectral data processing and analysis techniques that are of broad applicability.Organized into five chapters, this volume begins with an overview of the instrumentation used for obtaining field data. This text then reviews the contribution that space-borne spectroscopy in the thermal IR has made to the understanding of the planets. Other chapters consider the instruments that have recorded the planetary emission spectra. This book discusses as well

  10. Determination of free amino compounds in betalainic fruits and vegetables by gas chromatography with flame ionization and mass spectrometric detection.

    Science.gov (United States)

    Kugler, Florian; Graneis, Stephan; Schreiter, Pat P-Y; Stintzing, Florian C; Carle, Reinhold

    2006-06-14

    Amino acids and amines are the precursors of betalains. Therefore, the profiles of free amino compounds in juices obtained from cactus pears [Opuntia ficus-indica (L.) Mill. cv. Bianca, cv. Gialla, and cv. Rossa], pitaya fruits [Selenicereus megalanthus (K. Schumann ex Vaupel) Moran, Hylocereus polyrhizus (Weber) Britton & Rose, and Hylocereus undatus (Haworth) Britton & Rose], and in extracts from differently colored Swiss chard [Beta vulgaris L. ssp. cicla (L.) Alef. cv. Bright Lights] petioles and red and yellow beets (B. vulgaris L. ssp. vulgaris var. conditiva Alef. cv. Burpee's Golden) were investigated for the first time. Amino compounds were derivatized with propyl chloroformate. While gas chromatography (GC) with mass spectrometry was used for peak assignment, GC flame ionization detection was applied for quantification of individual compounds. Whereas proline was the major free amino compound of cactus pear and pitaya fruit juices, glutamine dominated in Swiss chard stems and beets, respectively. Interestingly, extremely high concentrations of dopamine were detected in Swiss chard stems and beets. Furthermore, the cleavage of betaxanthins caused by derivatization in alkaline reaction solutions is demonstrated for the first time. Amino acids and amines thus released might increase the actual free amino compound contents of the respective sample. To evaluate the contribution of betaxanthin cleavage to total amino acid and amine concentration, isolated betaxanthins were derivatized according to the "EZ:faast" method prior to quantification of the respective amino compounds released. On a molar basis, betaxanthin contribution to overall amino compound contents was always below 6.4%.

  11. Mass Spectrometric Analysis of Pristine Aerosol Particles During the wet Season of Amazonia - Detection of Primary Biological Particles?

    Science.gov (United States)

    Schneider, J.; Zorn, S. R.; Freutel, F.; Borrmann, S.; Chen, Q.; Farmer, D. K.; Jimenez, J. L.; Flores, M.; Roldin, P.; Artaxo, P.; Martin, S. T.

    2008-12-01

    The contribution of primary biological aerosol (POA) particles to the natural organic aerosol is a subject of current research. Estimations of the POA contribution to the total aerosol particle concentration range between 25 and 80%, depending on location and season. Especially in the tropical rain forest it is expected that POA is a major source of supermicron, possibly also of submicron particles. During AMAZE (Amazonian Aerosol CharacteriZation Experiment), a field project near Manaus, Brazil, in February/March 2008, an Aerodyne ToF-AMS was equipped with a high pressure aerodynamic lens. This high pressure lens (operating pressure 14.6 torr) is designed with the objective to extend the detectable size range of the AMS into the supermicron size range where primary biological particles are expected. Size distribution measured by the AMS were compared with size distribution from an optical particle counter and indicate that the high pressure lens has a 50% cut-off at a vacuum aerodynamic diameter of about 1 μm, but still has significant transmission up to a vacuum aerodynamic diameter of about 2 μm, thus extending the detectable size range of the AMS into the coarse mode. The measuring instruments were situated in a container at ground level. The aerosol was sampled through a 40 m vertical, laminar inlet, which was heated and dried to maintain a relative humidity between 30 and 40%. The inlet was equipped with a 7 μm cut-off cyclone. Size distributions recorded with an optical particle counter parallel to the AMS show that the inlet transmitted aerosol particles up to an optically detected diameter of 10 μm. POA particles like plant fragments, pollen, spores, fungi, viruses etc. contain chemical compounds as proteins, sugars, amino acids, chlorophyll, and cellular material as cellulose. Laboratory experiments have been performed in order to identify typical mass spectral patterns of these compounds. These laboratory data were compared to size resolved particle

  12. Determination of plasticizers included in balloon by solid phase microextraction and gas chromatography with mass spectrometric detection.

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.M.; Kim, J.H.; Ryu, J.Ch.; Kim, Y.M.; Lee, K.B. [Korea Institute of Science and Technology, Seoul (Korea)

    2001-02-01

    Solid-phase microextraction (SPME) with 85 {mu}m polyacrylate fiber, coupled to gas chromatography-mass spectrometry was used to analyze the plasticizers contained in balloon samples. The balloons were identified to be made of polyisoprene by IR spectroscopy. The plasticizers extracted from the balloon samples soaked in acetone-added water solvent for an hour were quantified by external standard method using nine kinds of plasticizers. The quantification method was validated for standard plasticizers in the range of 0.25-25 {mu}g/g. The detection limits were 0.11-0.38 {mu}g/g for different plasticizers. The RSDs for the reproducibility of this quantitation method were 3.7-14.2%. A few of balloons included risky level of plasticizer concerned as an endocrine disrupter, and it is necessary to regulate these products. (author). 10 refs., 3 tabs., 4 figs.

  13. Detection of drugs in lifted cyanoacrylate-developed latent fingermarks using two laser desorption/ionisation mass spectrometric methods.

    Science.gov (United States)

    Sundar, Latha; Rowell, Frederick

    2014-02-01

    This paper describes a method for lifting cyanoacrylate (CNA)-developed latent fingermarks from a glass surface and the detection of five drugs in lifted marks from fingers that had been in contact with the drugs, using Surface Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry (SALDI-TOF-MS) or Matrix Assisted Laser Desorption Ionisation TOF-MS (MALDI-TOF-MS). Two drugs of abuse (cocaine and methadone) and three therapeutic drugs (aspirin, paracetamol and caffeine) were used as contact residues. Latent fingermarks spiked with the drugs were subjected to CNA fuming followed by dusting with ARRO SupraNano™ MS black magnetic powder (SALDI-TOF-MS) or 2,5-dihydroxybenzoic acid (DHB) (MALDI-TOF-MS). The dusted mark was then exposed to solvent vapour before lifting with a commercial fingerprint lifting tape following established procedures. The presence of the drugs was then confirmed by direct analysis on the tape without further processing using SALDI- or MALDI-TOF-MS. The black magnetic fingerprint powder provided visual enhancement of the CNA-fingermark while no visual enhancement was observed for marks dusted with DHB powder. Similar [M + H](+) peaks for all the drug analytes were observed for both methods along with some sodium and potassium adducts for SALDI-MS and some major fragment ions but the SALDI signals were generally more intense. Simple exposure to acetone vapour of the CNA-developed marks enabled their effective transfer onto the tape which was crucial for subsequent MS detection of the analytes.

  14. Flame atomic absorption spectrometric (FAAS) determination of copper, iron and zinc in food samples after solid-phase extraction on Schiff base-modified duolite XAD 761.

    Science.gov (United States)

    Ghaedi, M; Mortazavi, K; Montazerozohori, M; Shokrollahi, A; Soylak, M

    2013-05-01

    The present study involves the development of solid-phase extraction (SPE) procedure for the preconcentration of trace amounts of copper (Cu(2+)), iron (Fe(3+)) and zinc (Zn(2+)) ions on duolite XAD 761 modified by bis(2-hydroxyacetophenone)-2,2-dimethyl-1,3-propanediimine(BHAPDMPDI). The complexation between the metal ions and the proposed ligand was investigated potentiometrically. The metal ions retained on the sorbent were quantitatively determined via complexation with BHAPDMPDI. The complexed metal ions were efficiently eluted using 6 mL of 4 mol L(-1) nitric acid in acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ions were optimized. Using the optimized parameters, the linear response of the SPE method for Cu(2+), Zn(2+) and Fe(3+) ions were in the ranges of 0.01-0.34, 0.01-0.28 and 0.02-0.31 μg mL(-1), respectively, and the detection limits for Cu(2+), Zn(2+) and Fe(3+) ions were 1.8, 1.6 and 2.4 μg mL(-1), respectively. The proposed method exhibits a preconcentration factor of 208 for all of the ions studied and an enhancement factor for Cu(2+), Fe(3+) and Zn(2+) ions of 34, 28 and 38, respectively. The presented results demonstrate the successful application of the proposed method for the determination of these metal ions in some real samples with high recoveries (> 95%) and reasonable relative standard deviation (RDS <5%).

  15. Flame atomic absorption spectrometric (FAAS) determination of copper, iron and zinc in food samples after solid-phase extraction on Schiff base-modified duolite XAD 761

    Energy Technology Data Exchange (ETDEWEB)

    Ghaedi, M., E-mail: m_ghaedi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Mortazavi, K. [Chemistry Department, Gachsaran Branch, Islamic Azad University, Gachsaran (Iran, Islamic Republic of); Montazerozohori, M. [Chemistry Department, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Shokrollahi, A. [Chemistry Department, Gachsaran Branch, Islamic Azad University, Gachsaran (Iran, Islamic Republic of); Soylak, M. [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

    2013-05-01

    The present study involves the development of solid-phase extraction (SPE) procedure for the preconcentration of trace amounts of copper (Cu{sup 2+}), iron (Fe{sup 3+}) and zinc (Zn{sup 2+}) ions on duolite XAD 761 modified by bis(2-hydroxyacetophenone)-2,2-dimethyl-1,3-propanediimine(BHAPDMPDI). The complexation between the metal ions and the proposed ligand was investigated potentiometrically. The metal ions retained on the sorbent were quantitatively determined via complexation with BHAPDMPDI. The complexed metal ions were efficiently eluted using 6 mL of 4 mol L{sup −1} nitric acid in acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ions were optimized. Using the optimized parameters, the linear response of the SPE method for Cu{sup 2+}, Zn{sup 2+} and Fe{sup 3+} ions were in the ranges of 0.01–0.34, 0.01–0.28 and 0.02–0.31 μg mL{sup −1}, respectively, and the detection limits for Cu{sup 2+}, Zn{sup 2+} and Fe{sup 3+} ions were 1.8, 1.6 and 2.4 μg mL{sup −1}, respectively. The proposed method exhibits a preconcentration factor of 208 for all of the ions studied and an enhancement factor for Cu{sup 2+}, Fe{sup 3+} and Zn{sup 2+} ions of 34, 28 and 38, respectively. The presented results demonstrate the successful application of the proposed method for the determination of these metal ions in some real samples with high recoveries (> 95%) and reasonable relative standard deviation (RDS < 5%). Highlights: ► Highly efficient adsorbent for dye removal was synthesized. ► The sorbent was fully characterized. ► The proposed method has a potential of a waste water treatment alternative. ► Excellent properties of the sorbent have been illustrated in detail.

  16. Determination and characterization of phytochelatins by liquid chromatography coupled with on line chemical vapour generation and atomic fluorescence spectrometric detection.

    Science.gov (United States)

    Bramanti, Emilia; Toncelli, Daniel; Morelli, Elisabetta; Lampugnani, Leonardo; Zamboni, Roberto; Miller, Keith E; Zemetra, Joseph; D'Ulivo, Alessandro

    2006-11-10

    Liquid chromatography (LC) coupled on line with UV/visible diode array detector (DAD) and cold vapour generation atomic fluorescence spectrometry (CVGAFS) has been developed for the speciation, determination and characterization of phytochelatins (PCs). The method is based on a bidimensional approach, e.g. on the analysis of synthetic PC solutions (apo-PCs and Cd(2+)-complexed PCs) (i) by size exclusion chromatography coupled to UV diode array detector (SEC-DAD); (ii) by the derivatization of PC -SH groups in SEC fractions by p-hydroxymercurybenzoate (PHMB) and the indirect detection of PC-PHMB complexes by reversed phase liquid chromatography coupled to atomic fluorescence detector (RPLC-CVGAFS). MALDI-TOF/MS (matrix assisted laser desorption ionization time of flight mass spectrometry) analysis of underivatized synthetic PC samples was performed in order have a qualitative information of their composition. Quantitative analysis of synthetic PC solutions has been performed on the basis of peak area of PC-PHMB complexes of the mercury specific chromatogram and calibration curve of standard solution of glutathione (GSH) complexed to PHMB (GS-PHMB). The limit of quantitation (LOQ) in terms of GS-PHMB complex was 90 nM (CV 5%) with an injection volume of 35 microL, corresponding to 3.2 pmol (0.97 ng) of GSH. The method has been applied to analysis of extracts of cell cultures from Phaeodactylum tricornutum grown in Cd-containing nutrient solutions, analysed by SEC-DAD-CVGAFS and RPLC-DAD-CVGAFS.

  17. Identification of organic sulfur compounds in coal bitumen obtained by different extraction techniques using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometric detection.

    Science.gov (United States)

    Machado, Maria Elisabete; Fontanive, Fernando Cappelli; de Oliveira, José Vladimir; Caramão, Elina Bastos; Zini, Cláudia Alcaraz

    2011-11-01

    The determination of organic sulfur compounds (OSC) in coal is of great interest. Technically and operationally these compounds are not easily removed and promote corrosion of equipment. Environmentally, the burning of sulfur compounds leads to the emission of SO(x) gases, which are major contributors to acid rain. Health-wise, it is well known that these compounds have mutagenic and carcinogenic properties. Bitumen can be extracted from coal by different techniques, and use of gas chromatography coupled to mass spectrometric detection enables identification of compounds present in coal extracts. The OSC from three different bitumens were tentatively identified by use of three different extraction techniques: accelerated solvent extraction (ASE), ultrasonic extraction (UE), and supercritical-fluid extraction (SFE). Results obtained from one-dimensional gas chromatography (1D GC) coupled to quadrupole mass spectrometric detection (GC-qMS) and from two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC × GC-TOFMS) were compared. By use of 2D GC, a greater number of OSC were found in ASE bitumen than in SFE and UE bitumens. No OSC were identified with 1D GC-qMS, although some benzothiophenes and dibenzothiophenes were detected by use of EIM and SIM modes. GC × GC-TOFMS applied to investigation of OSC in bitumens resulted in analytical improvement, as more OSC classes and compounds were identified (thiols, sulfides, thiophenes, naphthothiophenes, benzothiophenes, and benzonaphthothiophenes). The roof-tile effect was observed for OSC and PAH in all bitumens. Several co-elutions among analytes and with matrix interferents were solved by use of GC × GC.

  18. A mid-infrared absorption diagnostic for acetylene detection

    KAUST Repository

    KC, Utsav

    2015-05-14

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm−1 over a wide range of temperatures (1000–2200 K) and pressures (1–5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene. © 2015 Springer-Verlag Berlin Heidelberg

  19. Filtering absorption and visual detection of methylene blue by nitrated cellulose acetate membrane

    Energy Technology Data Exchange (ETDEWEB)

    He, Shengbin; Fang, He; Xu, Xiaoping [College of Chemistry, Fuzhou University, Fuzhou (China)

    2016-04-15

    Wastewater-containing industrial dyes are quite harmful since most dyes are stable and toxic to humans. Detection and removing of those dyes from wastewater is necessary to ensure water supply safety. In present work, a nitrated cellulose acetate (NCA) microfiltration membrane was developed for specific absorption and visible detection of methylene blue (MB). The NCA microfiltration membrane overcomes the defect of high driven pressure in nanofiltration or ultrafiltration process. By absorption effect, the NCA membrane also overcomes the defect of low retention rate of traditional microfiltration membrane to dyes. The residual MB can be removed quickly and thoroughly by microfiltration absorption. The microfiltration membrane can also be used for visual detection of MB by concentrating the MB on membrane. The limit of detection is as low as 0.001 mg/L. The detection method is simple and free of large-scale instrument, and can be used as a portable device for spot detection of dye-contaminated water.

  20. Gas detection techniques with fiber optical spectrum absorption at near-IR wavelength

    Science.gov (United States)

    Liu, Tiegen; Liu, Kun; Jiang, Junfeng; Peng, Gangding; Wang, Yan; Jia, Dagong; Zhang, Hongxia; Jing, Wencai; Zhang, Yimo

    2010-04-01

    Detection of pollution gas is important in environmental and pollution monitoring, which can be used widely in mining and petrochemical industry. Fiber optical spectrum absorption (FOSA) at near-IR wavelength is widely used in gas detection due to its essential advantages. It has attracted considerable attention, and there are several types and methods in FOSA. Wavelength modulation technique (WMT) is one of them, which will improve the gas detection sensitivity dramatically. This technique can be realized by detecting the intensity of the second-harmonic component signal. Intra-cavity laser spectroscopy (ICLS) is another alternative technique for high sensitivity absorption measurement. With an absorber directly placed within the laser cavity, a short absorption cell can be transformed into a high sensitivity system. But the practical sensitivity is obviously less than the theoretical value. The authors did some works in these fields and have obtained some remarkable progress. With broad reflectors instead of FBG as mirror of the cavity and wavelength sweep technique (WST), several absorption spectra of detected gas can be collected. And the detection sensitivity can be enhanced sharply by averaging the results of each spectrum, with acetylene sensitivity less than 100 ppm . When ICLS is used combined with WST and WMT, the detection sensitivity of acetylene can be enhanced further. The sensitivity is less than 75 ppm. By using FBGs as wavelength references, the absorption wavelength of the detected gas is obtained, which can be used to realize gas recognition. The system is capable of accessing into fiber intelligent sensing network.

  1. Airborne Measurements of CO2 Column Absorption and Range Using a Pulsed Direct-Detection Integrated Path Differential Absorption Lidar

    Science.gov (United States)

    Abshire, James B.; Riris, Haris; Weaver, Clark J.; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Browell, Edward V.

    2013-01-01

    We report on airborne CO2 column absorption measurements made in 2009 with a pulsed direct-detection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United States. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The lidar measurement statistics were also calculated for each flight as a function of altitude. The optical depth varied nearly linearly with altitude, consistent with calculations based on atmospheric models. The scatter in the optical depth measurements varied with aircraft altitude as expected, and the median measurement precisions for the column varied from 0.9 to 1.2 ppm. The altitude range with the lowest scatter was 810 km, and the majority of measurements for the column within it had precisions between 0.2 and 0.9 ppm.

  2. Gas trace detection with cavity enhanced absorption spectroscopy: a review of its process in the field

    Science.gov (United States)

    Liu, Siqi; Luo, Zhifu; Tan, Zhongqi; Long, Xingwu

    2016-11-01

    Cavity-enhanced absorption spectroscopy (CEAS) is a technology in which the intracavity absorption is deduced from the intensity of light transmitted by the high finesse optical cavity. Then the samples' parameters, such as their species, concentration and absorption cross section, would be detection. It was first proposed and demonstrated by Engeln R. [1] and O'Keefe[2] in 1998. This technology has extraordinary detection sensitivity, high resolution and good practicability, so it is used in many fields , such as clinical medicine, gas detection and basic physics research. In this paper, we focus on the use of gas trace detection, including the advance of CEAS over the past twenty years, the newest research progresses, and the prediction of this technology's development direction in the future.

  3. In-house validation of a method for determination of silver nanoparticles in chicken meat based on asymmetric flow field-flow fractionation and inductively coupled plasma mass spectrometric detection

    DEFF Research Database (Denmark)

    Löschner, Katrin; Navratilova, Jana; Grombe, Ringo;

    2015-01-01

    spectrometric detection (AF4-ICP-MS) was applied for quantitative analysis of silver nanoparticles (AgNPs) in a chicken meat matrix following enzymatic sample preparation. For the first time an analytical validation of nanoparticle detection in a food matrix by AF4-ICP-MS has been carried out and the results......Nanomaterials are increasingly used in food production and packaging, and validated methods for detection of nanoparticles (NPs) in foodstuffs need to be developed both for regulatory purposes and product development. Asymmetric flow field-flow fractionation with inductively coupled plasma mass...... showed repeatable and intermediately reproducible determination of AgNP mass fraction and size. The findings demonstrated the potential of AF4-ICP-MS for quantitative analysis of NPs in complex food matrices for use in food monitoring and control. The accurate determination of AgNP size distribution...

  4. Spectrometric characteristics of polystyrene scintillation films

    CERN Document Server

    Astvatsaturov, A R; Gavalyan, V B; Gavalyan, V G

    1999-01-01

    The spectrometric characteristics of five types of polystyrene scintillation films with thicknesses of 10, 30, 50 and 80 mu m and of analogous 250 mu m thick plates irradiated with sup 2 sup 3 sup 9 Pu, sup 2 sup 3 sup 8 Pu and sup 2 sup 2 sup 6 Ra sources of alpha-particles have been studied. The prospects of utilization of scintillation films as radiators for detection of heavy charged particles and measurement of their energy was experimentally shown.

  5. Use of Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometric Detection and Random Forest Pattern Recognition Techniques for Classifying Chemical Threat Agents and Detecting Chemical Attribution Signatures.

    Science.gov (United States)

    Strozier, Erich D; Mooney, Douglas D; Friedenberg, David A; Klupinski, Theodore P; Triplett, Cheryl A

    2016-07-19

    In this proof of concept study, chemical threat agent (CTA) samples were classified to their sources with accuracies of 87-100% by applying a random forest statistical pattern recognition technique to analytical data acquired by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC × GC-TOFMS). Three organophosphate pesticides, chlorpyrifos, dichlorvos, and dicrotophos, were used as the model CTAs, with data collected for 4-6 sources per CTA and 7-10 replicate analyses per source. The analytical data were also evaluated to determine tentatively identified chemical attribution signatures for the CTAs by comparing samples from different sources according to either the presence/absence of peaks or the relative responses of peaks. These results demonstrate that GC × GC-TOFMS analysis in combination with a random forest technique can be useful in sample classification and signature identification for pesticides. Furthermore, the results suggest that this combination of analytical chemistry and statistical approaches can be applied to forensic analysis of other chemicals for similar purposes.

  6. Spectrometric techniques 2

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume II provides information pertinent to vacuum ultraviolet techniques to complete the demonstration of the diversity of methods available to the spectroscopist interested in the ultraviolet visible and infrared spectral regions. This book discusses the specific aspects of the technique of Fourier transform spectroscopy.Organized into five chapters, this volume begins with an overview of the large number of systematic effects in the recording of an interferogram. This text then examines the design approach for a Fourier transform spectrometer with focus on optics.

  7. Infrared absorption spectroscopy of CO 2-Ar complexes

    Science.gov (United States)

    Sharpe, S. W.; Sheeks, R.; Wittig, C.; Beaudet, R. A.

    1988-10-01

    The ν 4 rovibrational band of CO 2-Ar near 2350 cm -1 (i.e. CO 2 asymmetric stretch) has been recorded in absorption at 8 K using a tunable diode laser. Rotational constants for both ν 4=0 and 1 are very similar, and indicate a T-shaped geometry. It was not possible to detect this species mass spectrometrically (18-70 eV electrons), indicating extensive fragmentation.

  8. HI Absorption Lines Detected from the Arecibo Legacy Fast ALFA Survey Data

    Science.gov (United States)

    Zhong-zu, Wu; Martha P, Haynes; Riccardo, Giovanelli; Ming, Zhu; Ru-rong, Chen

    2015-10-01

    We present some preliminary results of an on-going study of HI 21-cm absorption lines based on the 40% survey data released by the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). (1) Ten HI candidate absorbers have been detected. Five of them are previously published in the literature, and the rest of them are new detections that need further confirmation. (2) For those sources with no detected absorptions, we have calculated the upper limit of their foreground HI column density NHI. The statistical result of the NHI distribution indicates that the ratio Ts/f between the averaged spin temperature and coverage factor for DLAs (the damped Lyα systems) might be larger than 500 K. The radio frequency interference (RFI) and standing wave are the main factors affecting the detection of HI absorption lines, which have been analyzed and discussed as well in order to find a method of solution. Our study can serve as a pathfinder for the future large-scale search of HI 21-cm absorption lines using the Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST), which is an Arecibo-type radio telescope currently under construction in China with greatly increased sensitivity, bandwidth, and observational sky area. As prospects, we have discussed two types of observational studies of HI absorption lines toward extragalactic sources using the FAST telescope.

  9. Expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution/high accuracy mass spectrometric detection of stanozolol glucuronides in human sports drug testing.

    Science.gov (United States)

    Schänzer, Wilhelm; Guddat, Sven; Thomas, Andreas; Opfermann, Georg; Geyer, Hans; Thevis, Mario

    2013-01-01

    Anabolic-androgenic steroids (AAS) represent one of the most frequently detected classes of prohibited substances in doping controls. Due to their long-lasting beneficial effects on athletic performance, utmost retrospectivity via urine analysis is desirable and accomplished by targeting long-term metabolites of the respective drugs. In case of stanozolol, a substantial variety of metabolites has enabled the identification of numerous adverse analytical findings in the past, and recent studies concerning complementary phase-I and phase-II metabolites has further expanded the windows of opportunity for detecting the abuse of stanozolol. In this study, the utility of liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry (LC-MS/MS) for the detection of 3'-OH-stanozolol glucuronide in sports drug testing is presented and the identification of two additional and so far unreported metabolites is shown. The structures of the complementary glucuronic acid conjugates were attributed to stanozolol-N-glucuronide and 17-epistanozolol-N-glucuronide. By means of chemical synthesis, stanozolol-N-glucuronide was prepared and used to corroborate the suggested structures. The 3'-OH-stanozolol glucuronide and the newly identified target compounds were implemented into routine sports drug test assays consisting of direct injection LC-MS/MS or solid-phase extraction (SPE) followed by LC-MS/MS. A considerably expanded detection window for stanozolol abuse was demonstrated compared to the use of conventional phase-I metabolites and methodologies based on, for example, low resolution LC-MS/MS or gas chromatography-tandem mass spectrometry (GC-MS/MS). The commercial availability of 3'-OH-stanozolol glucuronide has been of great value for confirmatory purposes, and 17-epistanozolol-N-glucuronide was found to be a favourable long-term metabolite for doping controls as it was observed up to 28 days post-administration of the drug. Applying the established

  10. Infrared differential absorption lidar for stand-off detection of chemical agents

    Indian Academy of Sciences (India)

    A K Razdan; S Veerabuthiran; M K Jindal; R K Sharma

    2014-02-01

    A compact trolley-mounted pulsed transverse electric atmospheric pressure (TEA) carbon dioxide laser-based differential absorption lidar (DIAL) system capable of stand-off detection of chemical clouds in aerosol and vapour form upto about 200 m range in the atmosphere has been developed and assembled at Laser Science and Technology Centre (LASTEC), Delhi. The system was tested successfully with diethyl ether (DEE) (a toxic industrial chemical (TIC)) and differential absorption signals at on (strong absorption, 9R16) and off (weak absorption, 10R26) wavelengths were recorded for stand-off distances upto ∼100 m (open air ground path). This paper discusses the technical details of trolley-mounted CO2 DIAL system and the data generated during the test and evaluation of this sensor using DEE aerosols.

  11. Absorption of human skin and its detecting platform in the process of laser cosmetology

    Science.gov (United States)

    Zhang, Yong-Lin; Ouyang, Li; Wang, Yang

    2000-10-01

    Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

  12. Comparison of serum copper determination by colorimetric and atomic absorption spectrometric methods in seven different laboratories. The S.F.B.C. (Société Française de Biologie Clinique) Trace Element Group.

    Science.gov (United States)

    Arnaud, J; Chappuis, P; Zawislak, R; Houot, O; Jaudon, M C; Bienvenu, F; Bureau, F

    1993-02-01

    An interlaboratory collaborative trial was conducted on the determination of serum copper using two different methods, based on colorimetry (test combination Copper, Boehringer Mannheim, Mannheim, Germany) and flame atomic absorption spectrometry (FAAS). The general performance of the colorimetric method was below that of FAAS, except for sensitivity and linear range, as assessed by detection limit (0.44 versus 1.32 mumol/L) and upper limit of linearity (150 versus 50 mumol/L). The range of the between-run CVs and the recovery of standard additions were, respectively, 2.3-11.9% and 92-127% for the colorimetric method and 1.1-6.0% and 93-101% for the FAAS method. Interferences were minimal with both methods. The two techniques correlated satisfactorily (the correlation coefficients ranged from 0.945-0.970 among laboratories) but the colorimetric assay exhibited slightly higher results than the FAAS method. Each method was transferable among laboratories.

  13. A CCD-based system for the detection of DNA in electrophoresis gels by UV absorption

    Science.gov (United States)

    Mahon, Alex R.; MacDonald, John H.; Ott, Robert J.; Mainwood, Alison

    1999-06-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled nucleic acids in agarose gels is presented. The technique is based on ultraviolet (UV) absorption by nucleotides. A deuterium source illuminates individual sample lanes of an electrophoresis gel via an array of optical fibres. As DNA bands pass through the illuminated region of the gel the amount of UV light transmitted is reduced because of absorption by the DNA. During electrophoresis the regions of DNA are detected on-line using a UV-sensitive charge coupled device (CCD). As the absorption coefficient is proportional to the mass of DNA the technique is inherently quantitative. The mass of DNA in a region of the gel is approximately proportional to the integrated signal in the corresponding section of the CCD image. This system currently has a detection limit of less than 1.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. In addition the DNA sample remains in its native state. The removal of the carcinogenic dye from the detection procedure greatly reduces associated biological hazards.

  14. On-line sample processing involving microextraction techniques as a front-end to atomic spectrometric detection for trace metal assays: A review

    Energy Technology Data Exchange (ETDEWEB)

    Miró, Manuel, E-mail: manuel.miro@uib.es [FI-TRACE Group, Department of Chemistry, Faculty of Sciences, University of the Balearic Islands, E-07122 Palma de Mallorca, Illes Balears (Spain); Hansen, Elo Harald [Granåsen 93, DK-2800 Kgs. Lyngby (Denmark)

    2013-06-11

    Graphical abstract: -- Highlights: •Role of flow injection in automation of microextraction techniques for metal assays. •On-line coupling of liquid phase microextraction (LPME) to atomic spectrometry. •Critical evaluation of on-line single drop and dispersive LPME. •On-line coupling of micro-solid phase extraction (μSPE) to atomic spectrometry. •Critical appraisal of magnetic/carbon nanoparticles and biomass for on-line μSPE. -- Abstract: Within the last decade, liquid-phase microextraction (LPME) and micro-solid phase extraction (μSPE) approaches have emerged as substitutes for conventional sample processing procedures for trace metal assays within the framework of green chemistry. This review surveys the progress of the state of the art in simplification and automation of microextraction approaches by harnessing to the various generations of flow injection (FI) as a front end to atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS) or inductively coupled plasma atomic emission spectrometry or mass spectrometry (ICP-AES/MS). It highlights the evolution of flow injection analysis and related techniques as vehicles for appropriate sample presentation to the detector and expedient on-line matrix separation and pre-concentration of trace levels of metals in troublesome matrices. Rather than being comprehensive this review is aimed at outlining the pros and cons via representative examples of recent attempts in automating green sample preparation procedures in an FI or sequential injection (SI) mode capitalizing on single-drop microextraction, dispersive liquid-phase microextraction and advanced sorptive materials including carbon and metal oxide nanoparticles, ion imprinted polymers, superparamagnetic nanomaterials and biological/biomass sorbents. Current challenges in the field are identified and the synergetic combination of flow analysis, nanotechnology and metal-tagged biomolecule detection is envisaged.

  15. Identification and determination of phase II nabumetone metabolites by high-performance liquid chromatography with photodiode array and mass spectrometric detection.

    Science.gov (United States)

    Nobilis, M; Holcapek, M; Kolárová, L; Kopecký, J; Kunes, M; Svoboda, Z; Kvetina, J

    2004-03-26

    Chromatographic analyses play an important role in the identification and determination of phase I and phase II drug metabolites. While the chemical standards of phase I metabolites are usually available from commercial sources or by various synthetic, degradation or isolation methods, the phase II drug metabolites have usually more complicated structures, their standards are in general inaccessible and their identification and determination require a comprehensive analytical approach involving the use of xenobiochemical methods and the employment of hyphenated analytical techniques. In this work, various high-performance liquid chromatography (HPLC) methods were employed in the evaluation of xenobiochemical experiments leading to the identification and determination of phase II nabumetone metabolites. Optimal conditions for the quantitative enzymatic deconjugation of phase II metabolites were found for the samples of minipig bile, small intestine contents and urine. Comparative HPLC analyses of the samples of above-mentioned biomatrices and of the same biomatrices after their enzymatic treatment using beta-glucuronidase and arylsulfatase afforded the qualitative and quantitative information about phase II nabumetone metabolites. Hereby, three principal phase II nabumetone metabolites (ether glucuronides) were discovered in minipig's body fluids and their structures were confirmed using liquid chromatography (LC)-electrospray ionization mass spectrometric (MS) analyses.

  16. Detection of Lyman continuum absorption in the BL Lacertae object PKS 0735+178

    Science.gov (United States)

    Bregman, J. N.; Glassgold, A. E.; Huggins, P. J.

    1981-01-01

    The detection of the Lyman edge in the BL Lac object PKS 0735+178 at the absorption red shift determined by optical measurements leads to a lower limit for the column density of atomic hydrogen, N(H I) not less than 4(17)/sq cm. The Lyman-alpha absorption line appears to have been detected, but only an approximate upper limit can be obtained from the data, of the order of 2(19)/sq cm. This amount of atomic hydrogen is less than that for a line of sight through the disk of a normal spiral galaxy. It is suggested that the absorbing material exists either in the halo of a galaxy or in the tenuous, extended, gaseous disk of a galaxy.

  17. Preconcentration of Pb(II), Cr(III), Cu(II), Ni(II) and Cd(II) ions in environmental samples by membrane filtration prior to their flame atomic absorption spectrometric determinations

    Energy Technology Data Exchange (ETDEWEB)

    Divrikli, Umit [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey)]. E-mail: udivrikli@pamukkale.edu.tr; Kartal, Aslihan Arslan [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Arts and Science, Department of Chemistry, 38039 Kayseri (Turkey); Elci, Latif [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey)

    2007-07-16

    A method for separation-preconcentration of Pb(II), Cr(III), Cu(II), Ni(II) and Cd(II) ions by membrane filtration has been described. The method based on the collection of analyte metal ions on a cellulose nitrate membrane filter and determination of analytes by flame atomic absorption spectrometry (FAAS). The method was optimized for several parameters including of pH, matrix effects and sample volume. The recoveries of analytes were generally in the range of 93-100%. The detection limits by 3 sigma for analyte ions were 0.02 {mu}g L{sup -1} for Pb(II), 0.3 {mu}g L{sup -1} for Cr(III), 3.1 {mu}g L{sup -1} for Cu(II), 7.8 {mu}g L{sup -1} for Ni(II) and 0.9 {mu}g L{sup -1} for Cd(II). The proposed method was applied to the determination of lead, chromium, copper, nickel and cadmium in tap waters and RM 8704 Buffalo River Sediment standard reference material with satisfactory results. The relative standard deviations of the determinations were below 10%.

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

    Science.gov (United States)

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

    2014-03-01

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

  19. Self-calibration wavelength modulation spectroscopy for acetylene detection based on tunable diode laser absorption spectroscopy

    Science.gov (United States)

    Huang, Qin-Bin; Xu, Xue-Mei; Li, Chen-Jing; Ding, Yi-Peng; Cao, Can; Yin, Lin-Zi; Ding, Jia-Feng

    2016-11-01

    The expressions of the second harmonic (2f) signal are derived on the basis of absorption spectral and lock-in theories. A parametric study indicates that the phase shift between the intensity and wavelength modulation makes a great contribution to the 2f signal. A self-calibration wavelength modulation spectroscopy (WMS) method based on tunable diode laser absorption spectroscopy (TDLAS) is applied, combining the advantages of ambient pressure, temperature suppression, and phase-shift influences elimination. Species concentration is retrieved simultaneously from selected 2f signal pairs of measured and reference WMS-2f spectra. The absorption line of acetylene (C2H2) at 1530.36 nm near-infrared is selected to detect C2H2 concentrations in the range of 0-400 ppmv. System sensitivity, detection precision and limit are markedly improved, demonstrating that the self-calibration method has better detecting performance than the conventional WMS. Project supported by the National Natural Science Foundation of China (Grant Nos. 61172047, 61502538, and 61501525).

  20. New Imaging Spectrometric Method for Rotary Object

    Institute of Scientific and Technical Information of China (English)

    方俊永; 赵达尊; 蒋月娟; 楚建军

    2003-01-01

    A new technique for imaging spectrometer for rotary object based on computed-tomography is proposed. A discrete model of this imaging spectrometric system is established, which is accordant to actual measurements and convenient for computation. In computer simulations with this method, projections of the object are detected by CCD while the object is rotating, and the original spectral images are numerically reconstructed from them by using the algorithm of computed-tomography. Simulation results indicate that the principle of the method is correct and it performs well for both broadband and narrow-band spectral objects.

  1. Wavelength modulation spectroscopy--digital detection of gas absorption harmonics based on Fourier analysis.

    Science.gov (United States)

    Mei, Liang; Svanberg, Sune

    2015-03-20

    This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method.

  2. Tunable Diode Laser Atomic Absorption Spectroscopy for Detection of Potassium under Optically Thick Conditions.

    Science.gov (United States)

    Qu, Zhechao; Steinvall, Erik; Ghorbani, Ramin; Schmidt, Florian M

    2016-04-05

    Potassium (K) is an important element related to ash and fine-particle formation in biomass combustion processes. In situ measurements of gaseous atomic potassium, K(g), using robust optical absorption techniques can provide valuable insight into the K chemistry. However, for typical parts per billion K(g) concentrations in biomass flames and reactor gases, the product of atomic line strength and absorption path length can give rise to such high absorbance that the sample becomes opaque around the transition line center. We present a tunable diode laser atomic absorption spectroscopy (TDLAAS) methodology that enables accurate, calibration-free species quantification even under optically thick conditions, given that Beer-Lambert's law is valid. Analyte concentration and collisional line shape broadening are simultaneously determined by a least-squares fit of simulated to measured absorption profiles. Method validation measurements of K(g) concentrations in saturated potassium hydroxide vapor in the temperature range 950-1200 K showed excellent agreement with equilibrium calculations, and a dynamic range from 40 pptv cm to 40 ppmv cm. The applicability of the compact TDLAAS sensor is demonstrated by real-time detection of K(g) concentrations close to biomass pellets during atmospheric combustion in a laboratory reactor.

  3. Invisible Active Galactic Nuclei. II Radio Morphologies & Five New HI 21 cm Absorption Line Detections

    CERN Document Server

    Yan, Ting; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2015-01-01

    We have selected a sample of 80 candidates for obscured radio-loud active galactic nuclei and presented their basic optical/near-infrared (NIR) properties in Paper 1. In this paper, we present both high-resolution radio continuum images for all of these sources and HI 21cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz VLA continuum observations find that 52 sources are compact or have substantial compact components with size 0.1 Jy at 4.9 GHz. The most compact 36 sources were then observed with the VLBA at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, a detection rate of CSOs ~3 times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty seven sources were observed for HI 21cm absorption at their photometric or spectroscopic redshifts with only ...

  4. Development, validation and application of an ultra high performance liquid chromatographic-tandem mass spectrometric method for the simultaneous detection and quantification of five different classes of veterinary antibiotics in swine manure.

    Science.gov (United States)

    Van den Meersche, Tina; Van Pamel, Els; Van Poucke, Christof; Herman, Lieve; Heyndrickx, Marc; Rasschaert, Geertrui; Daeseleire, Els

    2016-01-15

    In this study, a fast, simple and selective ultra high performance liquid chromatographic-tandem mass spectrometric (UHPLC-MS/MS) method for the simultaneous detection and quantification of colistin, sulfadiazine, trimethoprim, doxycycline, oxytetracycline and ceftiofur and for the detection of tylosin A in swine manure was developed and validated. First, a simple extraction procedure with acetonitrile and 6% trichloroacetic acid was carried out. Second, the supernatant was evaporated and the pellet was reconstituted in 1 ml of water/acetonitrile (80/20) and 0.1% formic acid. Extracts were filtered and analyzed by UHPLC-MS/MS on a Kinetex C18 column using gradient elution. The method developed was validated according to the criteria of Commission Decision 2002/657/EC. Recovery percentages varied between 94% and 106%, repeatability percentages were within the range of 1.7-9.2% and the intralaboratory reproducibility varied between 2.8% and 9.3% for all compounds, except for tylosin A for which more variation was observed resulting in a higher measurement uncertainty. The limit of detection and limit of quantification varied between 1.1 and 20.2 and between 3.5 and 67.3 μg/kg, respectively. This method was used to determine the presence and concentration of the seven antibiotic residues in swine manure sampled from ten different manure pits on farms where the selected antibiotics were used. A link was found between the antibiotics used and detected, except for ceftiofur which is injected at low doses and degraded readily in swine manure and was therefore not recovered in any of the samples. To the best of our knowledge, this is the first method available for the simultaneous extraction and quantification of colistin with other antibiotic classes. Additionally, colistin was never extracted from swine manure before. Another innovative aspect of this method is the simultaneous detection and quantification of five different classes of antibiotic residues in swine manure.

  5. HI emission and absorption in nearby, gas-rich galaxies II. -- sample completion and detection of intervening absorption in NGC 5156

    CERN Document Server

    Reeves, S N; Allison, J R; Koribalski, B S; Curran, S J; Pracy, M B; Phillips, C J; Bignall, H E; Reynolds, C

    2016-01-01

    We present the results of a survey for intervening 21cm HI absorption in a sample of 10 nearby, gas-rich galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This follows the six HIPASS galaxies searched in previous work and completes our full sample. In this paper we searched for absorption along 17 sightlines with impact parameters between 6 and 46 kpc, making one new detection. We also obtained simultaneous HI emission-line data, allowing us to directly relate the absorption-line detection rate to the HI distribution. From this we find the majority of the non-detections in the current sample are because sightline does not intersect the HI disc of the galaxy at sufficiently high column density, but that source structure is also an important factor. The detected absorption-line arises in the galaxy NGC 5156 ($z = 0.01$) at an impact parameter of 19 kpc. The line is deep and narrow with an integrated optical depth of 0.82 km s$^{-1}$. High resolution Australia Telescope Compact Array (ATCA) images at...

  6. WSRT detection of HI absorption in the z=3.4 damped Ly alpha system in PKS 0201+113

    NARCIS (Netherlands)

    deBruyn, AG; ODea, CP; Baum, SA

    1996-01-01

    We report the detection of a faint narrow HI absorption line at a redshift of 3.38 against the quasar PKS 0201+113 which itself has an emission redshift of 3.61. The absorption line redshift agrees, to within the errors, with that of a damped Ly alpha line. The line has a halfwidth of about 9 km s(-

  7. Development of a real-time absorption method for detecting the mercaptan odorizing mixture of natural gas

    NARCIS (Netherlands)

    Kireev, SV; Petrov, NG; Podolyako, EM; Shnyrev, SL

    2005-01-01

    The absorption of mercaptan mixtures used for odorizing natural gas and mixtures of natural gas is experimentally studied in the spectral range 2.5-20 mu m. An absorption method for the real-time detection of the odorant concentration is proposed. The method is based on intensity measurements of the

  8. Herschel-HIFI detections of hydrides towards AFGL 2591 (Envelope emission versus tenuous cloud absorption)

    CERN Document Server

    Bruderer, S; van Dishoeck, E F; Melchior, M; Doty, S D; van der Tak, F; Stäuber, P; Wampfler, S F; Dedes, C; Yıldız, U A; Pagani, L; Giannini, T; de Graauw, Th; Whyborn, N; Teyssier, D; Jellema, W; Shipman, R; Schieder, R; Honingh, N; Caux, E; Bächtold, W; Csillaghy, A; Monstein, C; Bachiller, R; Baudry, A; Benedettini, M; Bergin, E; Bjerkeli, P; Blake, G A; Bontemps, S; Braine, J; Caselli, P; Cernicharo, J; Codella, C; Daniel, F; di Giorgio, A M; Dominik, C; Encrenaz, P; Fich, M; Fuente, A; Goicoechea, J R; Helmich, F; Herczeg, G J; Herpin, F; Hogerheijde, M R; Jacq, T; Johnstone, D; Jørgensen, J K; Kristensen, L E; Larsson, B; Lis, D; Liseau, R; Marseille, M; McCoey, C; Melnick, G; Neufeld, D; Nisini, B; Olberg, M; Parise, B; Pearson, J C; Plume, R; Risacher, C; Santiago-Garcia, J; Saraceno, P; Shipman, R; Tafalla, M; van Kempen, T A; Visser, R; Wyrowski, F

    2010-01-01

    The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution and in multiple transitions. Here, we report deep integrations using HIFI in different lines of hydrides towards the high-mass star forming region AFGL 2591. Detected are CH, CH+, NH, OH+, H2O+, while NH+ and SH+ have not been detected. All molecules except for CH and CH+ are seen in absorption with low excitation temperatures and at velocities different from the systemic velocity of the protostellar envelope. Surprisingly, the CH(JF,P = 3/2_2,- - 1/2_1,+) and CH+(J = 1 - 0, J = 2 - 1) lines are detected in emission at the systemic velocity. We can assign the absorption features to a foreground cloud and an outflow lobe, while the CH and CH+ emission stems from the envelope. The observed abundance and excitation of CH and CH+ can be explained in the scenario of FUV irradiated outflow walls, where a cavity etched out by the outflow al...

  9. Multiplexed detection of xylene and trichloroethylene in water by photonic crystal absorption spectroscopy.

    Science.gov (United States)

    Lai, Wei-Cheng; Chakravarty, Swapnajit; Zou, Yi; Chen, Ray T

    2013-10-01

    We experimentally demonstrate simultaneous selective detection of xylene and trichloroethylene (TCE) using multiplexed photonic crystal waveguides (PCWs) by near-infrared optical absorption spectroscopy on a chip. Based on the slow light effect of photonic crystal structure, the sensitivity of our device is enhanced to 1 ppb (v/v) for xylene and 10 ppb (v/v) for TCE in water. Multiplexing is enabled by multimode interference power splitters and Y-combiners that integrate multiple PCWs on a silicon chip in a silicon-on-insulator platform.

  10. Bovine serum albumin-Cu(II) hybrid nanoflowers: An effective adsorbent for solid phase extraction and slurry sampling flame atomic absorption spectrometric analysis of cadmium and lead in water, hair, food and cigarette samples

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, Erkan [Department of Chemistry, Faculty of Sciences, Erciyes University, Kayseri 38039 (Turkey); Ocsoy, Ismail [Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, Kayseri 38039 (Turkey); Nanotechnology Research Center (ERNAM), Erciyes University, Kayseri 38039 (Turkey); Ozdemir, Nalan [Department of Chemistry, Faculty of Sciences, Erciyes University, Kayseri 38039 (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Department of Chemistry, Faculty of Sciences, Erciyes University, Kayseri 38039 (Turkey)

    2016-02-04

    Herein, the synthesis of bovine serum albumin-Cu(II) hybrid nanoflowers (BSA-NFs) through the building blocks of bovine serum albumin (BSA) and copper(II) ions in phosphate buffered saline (PBS) and their use as adsorbent for cadmium and lead ions are reported. The BSA-NFs, for the first time, were efficiently utilized as novel adsorbent for solid phase extraction (SPE) of cadmium and lead ions in water, food, cigarette and hair samples. The method is based on the separation and pre-concentration of Cd(II) and Pb(II) by BSA-NFs prior to determination by slurry analysis via flame atomic absorption spectrometry (FAAS). The analytes were adsorbed on BSA-NFs under the vortex mixing and then the ion-loaded slurry was separated and directly introduced into the flame AAS nebulizer by using a hand-made micro sample introduction system to eliminate a number of drawbacks. The effects of analytical key parameters, such as pH, amount of BSA-NFs, vortexing time, sample volume, and matrix effect of foreign ions on adsorbing of Cd(II) and Pb(II) were systematically investigated and optimized. The limits of detection (LODs) for Cd(II) and Pb(II) were calculated as 0.37 μg L{sup −1} and 8.8 μg L{sup −1}, respectively. The relative standard deviation percentages (RSDs) (N = 5) for Cd(II) and Pb(II) were 7.2%, and 5.0%, respectively. The accuracy of the developed procedure was validated by the analysis of certified reference materials (TMDA-53.3 Fortified Water, TMDA-70 Fortified Water, SPS-WW2 Waste Water, NCSDC-73349 Bush Branches and Leaves) and by addition/recovery analysis. The quantitative recoveries were obtained for the analysis of certified reference materials and addition/recovery tests. The method was successfully applied to the analysis of cadmium and lead in water, food, cigarette and hair samples. - Highlights: • The synthesis of bovine serum albumin-Cu(II) hybrid nanoflowers is reported. • The nanoflowers were utilized for solid phase microextraction of

  11. Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines

    CERN Document Server

    Qin, S -L; Comito, C; Möller, T; Rolffs, R; Müller, H S P; Belloche, A; Menten, K M; Lis, D C; Phillips, T G; Bergin, E A; Bell, T A; Crockett, N R; Blake, G A; Cabrit, S; Caux, E; Ceccarelli, C; Cernicharo, J; Daniel, F; Dubernet, M -L; Emprechtinger, M; Encrenaz, P; Falgarone, E; Gerin, M; Giesen, T F; Goicoechea, J R; Goldsmith, P F; Gupta, H; Herbst, E; Joblin, C; Johnstone, D; Langer, W D; Lord, S D; Maret, S; Martin, P G; Melnick, G J; Morris, P; Murphy, J A; Neufeld, D A; Ossenkopf, V; Pagani, L; Pearson, J C; Pérault, M; Plume, R; Salez, M; Schlemmer, S; Stutzki, J; Trappe, N; van der Tak, F F S; Vastel, C; Wang, S; Yorke, H W; Yu, S; Zmuidzinas, J; Boogert, A; Güsten, R; Hartogh, P; Honingh, N; Karpov, A; Kooi, J; Krieg, J M; Schieder, R; Diez-Gonzalez, M C; Bachille, R; Martin-Pintado, J; Baechtold, W; Olberg, M; Nordh, L H; Gill, J L; Chattopadhyay, G

    2010-01-01

    We have observed CH absorption lines ($J=3/2, N=1 \\leftarrow J=1/2, N=1$) against the continuum source Sgr~B2(M) using the \\textit{Herschel}/HIFI instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities and line widths are detected and identified. The narrower line width and lower column density clouds show `spiral arm' cloud characteristics, while the absorption component with the broadest line width and highest column density corresponds to the gas from the Sgr~B2 envelope. The observations show that each `spiral arm' harbors multiple velocity components, indicating that the clouds are not uniform and that they have internal structure. This line-of-sight through almost the entire Galaxy offers unique possibilities to study the basic chemistry of simple molecules in diffuse clouds, as a variety of different cloud classes are sampled simultaneously. We find that the linear relationship between CH and H$_2$ column dens...

  12. GBT Detection of Polarization-dependent HI Absorption and HI Outflows in Local ULIRGs and Quasars

    CERN Document Server

    Teng, Stacy H; Baker, Andrew J

    2013-01-01

    We present the results of a 21-cm HI survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Robert C. Byrd Green Bank Telescope (GBT). These remnants were selected from the Quasar/ULIRG Evolution Study (QUEST) sample of ultraluminous infrared galaxies (ULIRGs; L$_{8-1000 \\mu m} > 10^{12}$ L$_\\odot$) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGN) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of HI absorption (emission) to be 100% (29%) in ULIRGs with HI detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km s$^{-1}$ in some cases. Unexpectedly, we find polarization-dependent HI absorption in 57% of our spectra (88% and 63% of the...

  13. Chandra Detects Relativistic Broad Absorption Lines from APM 08279+5255

    CERN Document Server

    Chartas, G; Garmire, G P; Gallagher, S C

    2002-01-01

    We report the discovery of X-ray broad absorption lines (BALs) from the BALQSO APM 08279+5255 originating from material moving at relativistic velocities with respect to the central source. The large flux magnification by a factor of ~ 100 provided by the gravitational lens effect combined with the large redshift (z = 3.91) of the quasar have facilitated the acquisition of the first high signal-to-noise X-ray spectrum of a quasar containing X-ray BALs. Our analysis of the X-ray spectrum of APM 08279+5255 places the rest-frame energies of the two observed absorption lines at 8.1 and 9.8 keV. The detection of each of these lines is significant at the > 99.9% confidence level based on the F-test. Assuming that the absorption lines are from Fe xxv Kalpha, the implied bulk velocities of the X-ray BALs are ~ 0.2c and ~ 0.4c, respectively. The observed high bulk velocities of the X-ray BALs combined with the relatively short recombination time-scales of the X-ray absorbing gas imply that the absorbers responsible fo...

  14. [Study of the Detecting System of CH4 and SO2 Based on Spectral Absorption Method and UV Fluorescence Method].

    Science.gov (United States)

    Wang, Shu-tao; Wang, Zhi-fang; Liu, Ming-hua; Wei, Meng; Chen, Dong-ying; Wang, Xing-long

    2016-01-01

    According to the spectral absorption characteristics of polluting gases and fluorescence characteristics, a time-division multiplexing detection system is designed. Through this system we can detect Methane (CH4) and sulfur dioxide (SO2) by using spectral absorption method and the SO2 can be detected by using UV fluorescence method. The system consists of four parts: a combination of a light source which could be switched, the common optical path, the air chamber and the signal processing section. The spectral absorption characteristics and fluorescence characteristics are measured first. Then the experiment of detecting CH4 and SO2 through spectral absorption method and the experiment of detecting SO2 through UV fluorescence method are conducted, respectively. Through measuring characteristics of spectral absorption and fluorescence, we get excitation wavelengths of SO2 and CH4 measured by spectral absorption method at the absorption peak are 280 nm and 1.64 μm, respectively, and the optimal excitation wavelength of SO2 measured by UV fluorescence method is 220 nm. we acquire the linear relation between the concentration of CH4 and relative intensity and the linear relation between the concentration of SO2 and output voltage after conducting the experiment of spectral absorption method, and the linearity are 98.7%, 99.2% respectively. Through the experiment of UV fluorescence method we acquire that the relation between the concentration of SO2 and the voltage is linear, and the linearity is 99.5%. Research shows that the system is able to be applied to detect the polluted gas by absorption spectrum method and UV fluorescence method. Combing these two measurement methods decreases the costing and the volume, and this system can also be used to measure the other gases. Such system has a certain value of application.

  15. Quantitative determination of α-ionone, β-ionone, and β-damascenone and enantiodifferentiation of α-ionone in wine for authenticity control using multidimensional gas chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Langen, Johannes; Wegmann-Herr, Pascal; Schmarr, Hans-Georg

    2016-09-01

    Native concentrations of α-ionone, β-ionone, and β-damascenone were studied in various authentic and commercial wines. In addition, the enantiomeric distribution of α-ionone was determined and its merits as a potential marker for aroma adulteration in wine were discussed. For extraction of volatiles, headspace solid-phase microextraction (HS-SPME) was applied, followed by heart-cut multidimensional gas chromatography coupled to tandem mass spectrometric detection for trace-level analysis. The enantioselective analysis of α-ionone was achieved with octakis(2,3-di-O-pentyl-6-O-methyl)-γ-cyclodextrin as the chiral selector in the separation column for gas chromatography (GC). In all the authentic wines studied, α-ionone showed a high enantiomeric ratio in favor of the (R)-enantiomer. Since an illegal addition of α-ionone in a racemic form changes the enantiomeric ratio, this ratio may serve as an adulteration marker. Concentrations varied between authenticity markers in wine.

  16. Determination of aminopolycarboxylic acids in river water by solid-phase extraction on activated charcoal cartridges and gas chromatography with mass spectrometric detection. Method performance characteristics and estimation of the uncertainty.

    Science.gov (United States)

    Jiménez, Juan J

    2013-04-03

    A new sample preparation procedure to determine aminopolycarboxylic acids (ethylenediaminetetraacetic acid, EDTA, nitrilotriacetic acid, NTA, diethylenetriaminepentaacetic acid, DTPA, and cyclohexanediaminetetraacetic acid, CDTA) in river water is described. The procedure consists of the solid-phase extraction of the aminopolycaroxyllic acids on activated charcoal cartridges after increasing the ionic strength and acidifying the sample. The extract was eluted with methanol and the analytes were methylated in presence of BF3/methanol to determine them by GC with mass spectrometric detection. Recoveries were higher than 90% with good repeatabilities and inter-day precision for concentrations close to quantification limits (about 10 μg L(-1)) and higher. It has been verified that the proposed method is robust according to the Youden and Steiner test and free of matrix effects arisen from the presence of organic matter and iron(III) as deduced from statistical tests. A bottom-up approach was followed to estimate the uncertainty of the measured concentration. At concentrations close to 10 μg L(-1) the most relevant step of the method is the calculus of the interpolated concentration which has a high value of relative standard uncertainty.

  17. H I emission and absorption in nearby, gas-rich galaxies - II. Sample completion and detection of intervening absorption in NGC 5156

    Science.gov (United States)

    Reeves, S. N.; Sadler, E. M.; Allison, J. R.; Koribalski, B. S.; Curran, S. J.; Pracy, M. B.; Phillips, C. J.; Bignall, H. E.; Reynolds, C.

    2016-04-01

    We present the results of a survey for intervening 21 cm H I absorption in a sample of 10 nearby, gas-rich galaxies selected from the H I Parkes All-Sky Survey (HIPASS). This follows the six HIPASS galaxies searched in previous work and completes our full sample. In this paper, we searched for absorption along 17 sightlines with impact parameters between 6 and 46 kpc, making one new detection. We also obtained simultaneous H I emission-line data, allowing us to directly relate the absorption-line detection rate to the H I distribution. From this, we find the majority of the non-detections in the current sample are because sightline does not intersect the H I disc of the galaxy at sufficiently high column density, but that source structure is also an important factor. The detected absorption-line arises in the galaxy NGC 5156 (z = 0.01) at an impact parameter of 19 kpc. The line is deep and narrow with an integrated optical depth of 0.82 km s-1. High-resolution Australia Telescope Compact Array (ATCA) images at 5 and 8 GHz reveal that the background source is resolved into two components with a separation of 2.6 arcsec (500 pc at the redshift of the galaxy), with the absorption likely occurring against a single component. We estimate that the ratio of the spin temperature and covering factor, TS/f, is approximately 950 K in the outer disc of NGC 5156, but further observations using very long baseline interferometry would allow us to accurately measure the covering factor and spin temperature of the gas.

  18. GBT Detection of Polarization-Dependent HI Absorption and HI Outflows in Local ULIRGs and Quasars

    Science.gov (United States)

    Teng, Stacy H.; Veilleux, Sylvain; Baker, Andrew J.

    2013-01-01

    We present the results of a 21-cm HI survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Green Bank Telescope (GBT). These remnants were selected from the Quasar/ULIRG Evolution Study (QUEST) sample of ultraluminous infrared galaxies (ULIRGs; L(sub 8 - 1000 micron) > 10(exp 12) solar L) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGN) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of HI absorption (emission) to be 100% (29%) in ULIRGs with HI detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km/s in some cases. Unexpectedly, we find polarization-dependent HI absorption in 57% of our spectra (88% and 63% of the FIR-strong and FIR-weak quasars, respectively). We attribute this result to absorption of polarized continuum emission from these sources by foreground HI clouds. About 60% of the quasars displaying polarized spectra are radio-loud, far higher than the approx 10% observed in the general AGN population. This discrepancy suggests that radio jets play an important role in shaping the environments in these galaxies. These systems may represent a transition phase in the evolution of gas-rich mergers into "mature" radio galaxies.

  19. Application of atomic absorption spectroscopy for detection of multimetal traces in low-voltage electrical marks.

    Science.gov (United States)

    Jakubeniene, Marija; Zakaras, Algirdas; Minkuviene, Zita Nijole; Benoshys, Alvydas

    2006-08-10

    Application of atomic absorption spectroscopy to detect multimetal traces in injured skin is a promising tool for investigation of fatalities caused by electrocution. The present paper is aimed at testing the reliability of this method for metal traces detection in electric current marks and is focused on study of peculiarities of metal penetration into the skin exposed to a current impact. Bare aluminum wire, tin-lead coated copper multistrand wire, and zinc-plated steel rope were used to make electrical marks on pig skin. It is demonstrated that amount of copper, zinc, lead, and iron may serve as statistically reliable indicators for the type of wire, which caused the electrical mark, in spite of the background content of these metals in the skin without injury. Different penetration rates for different metals contained in the wire inflicting an electrical mark were observed.

  20. Metamaterial-enhanced vibrational absorption spectroscopy for the detection of protein molecules

    Science.gov (United States)

    Bui, Tung S.; Dao, Thang D.; Dang, Luu H.; Vu, Lam D.; Ohi, Akihiko; Nabatame, Toshihide; Lee, YoungPak; Nagao, Tadaaki; Hoang, Chung V.

    2016-01-01

    From visible to mid-infrared frequencies, molecular sensing has been a major successful application of plasmonics because of the enormous enhancement of the surface electromagnetic nearfield associated with the induced collective motion of surface free carriers excited by the probe light. However, in the lower-energy terahertz (THz) region, sensing by detecting molecular vibrations is still challenging because of low sensitivity, complicated spectral features, and relatively little accumulated knowledge of molecules. Here, we report the use of a micron-scale thin-slab metamaterial (MM) architecture, which functions as an amplifier for enhancing the absorption signal of the THz vibration of an ultrathin adsorbed layer of large organic molecules. We examined bovine serum albumin (BSA) as a prototype large protein molecule and Rhodamine 6G (Rh6G) and 3,3′-diethylthiatricarbocyanine iodide (DTTCI) as examples of small molecules. Among them, our MM significantly magnified only the signal strength of bulky BSA. On the other hand, DTTCI and Rh6G are inactive, as they lack low-frequency vibrational modes in this frequency region. The results obtained here clearly demonstrate the promise of MM-enhanced absorption spectroscopy in the THz region for detection and structural monitoring of large biomolecules such as proteins or pathogenic enzymes. PMID:27555217

  1. Metamaterial-enhanced vibrational absorption spectroscopy for the detection of protein molecules

    Science.gov (United States)

    Bui, Tung S.; Dao, Thang D.; Dang, Luu H.; Vu, Lam D.; Ohi, Akihiko; Nabatame, Toshihide; Lee, Youngpak; Nagao, Tadaaki; Hoang, Chung V.

    2016-08-01

    From visible to mid-infrared frequencies, molecular sensing has been a major successful application of plasmonics because of the enormous enhancement of the surface electromagnetic nearfield associated with the induced collective motion of surface free carriers excited by the probe light. However, in the lower-energy terahertz (THz) region, sensing by detecting molecular vibrations is still challenging because of low sensitivity, complicated spectral features, and relatively little accumulated knowledge of molecules. Here, we report the use of a micron-scale thin-slab metamaterial (MM) architecture, which functions as an amplifier for enhancing the absorption signal of the THz vibration of an ultrathin adsorbed layer of large organic molecules. We examined bovine serum albumin (BSA) as a prototype large protein molecule and Rhodamine 6G (Rh6G) and 3,3‧-diethylthiatricarbocyanine iodide (DTTCI) as examples of small molecules. Among them, our MM significantly magnified only the signal strength of bulky BSA. On the other hand, DTTCI and Rh6G are inactive, as they lack low-frequency vibrational modes in this frequency region. The results obtained here clearly demonstrate the promise of MM-enhanced absorption spectroscopy in the THz region for detection and structural monitoring of large biomolecules such as proteins or pathogenic enzymes.

  2. [The application of atomic absorption spectrometry in automatic transmission fault detection].

    Science.gov (United States)

    Chen, Li-dan; Chen, Kai-kao

    2012-01-01

    The authors studied the innovative applications of atomic absorption spectrometry in the automatic transmission fault detection. After the authors have determined Fe, Cu and Cr contents in the five groups of Audi A6 main metal in automatic transmission fluid whose travel course is respectively 10-15 thousand kilometers, 20-26 thousand kilometers, 32-38 thousand kilometers, 43-49 thousand kilometers, and 52-58 thousand kilometers by atomic absorption spectrometry, the authors founded the database of primary metal content in the Audi A6 different mileage automatic transmission fluid (ATF). The research discovered that the main metal content in the automatic transmission fluid increased with the vehicles mileage and its normal metal content level in the automatic transmission fluid is between the two trend lines. The authors determined the main metal content of automatic transmission fluid which had faulty symptoms and compared it with its database value. Those can not only judge the wear condition of the automatic transmission which had faulty symptoms but also help the automobile detection and maintenance personnel to diagnose automatic transmission failure reasons without disintegration. This reduced automobile maintenance costs, and improved the quality of automobile maintenance.

  3. Infrared absorption of gaseous CH2BrOO detected with a step-scan Fourier-transform absorption spectrometer.

    Science.gov (United States)

    Huang, Yu-Hsuan; Lee, Yuan-Pern

    2014-10-28

    CH2BrOO radicals were produced upon irradiation, with an excimer laser at 248 nm, of a flowing mixture of CH2Br2 and O2. A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to record temporally resolved infrared (IR) absorption spectra of reaction intermediates. Transient absorption with origins at 1276.1, 1088.3, 961.0, and 884.9 cm(-1) are assigned to ν4 (CH2-wagging), ν6 (O-O stretching), ν7 (CH2-rocking mixed with C-O stretching), and ν8 (C-O stretching mixed with CH2-rocking) modes of syn-CH2BrOO, respectively. The assignments were made according to the expected photochemistry and a comparison of observed vibrational wavenumbers, relative IR intensities, and rotational contours with those predicted with the B3LYP/aug-cc-pVTZ method. The rotational contours of ν7 and ν8 indicate that hot bands involving the torsional (ν12) mode are also present, with transitions 7(0)(1)12(v)(v) and 8(0)(1)12(v)(v), v = 1-10. The most intense band (ν4) of anti-CH2BrOO near 1277 cm(-1) might have a small contribution to the observed spectra. Our work provides information for directly probing gaseous CH2BrOO with IR spectroscopy, in either the atmosphere or laboratory experiments.

  4. XMM-Newton Spectroscopy of the X-ray Detected Broad Absorption Line QSO CSO 755

    Science.gov (United States)

    Brandt, Niel

    2005-01-01

    We present the results from XMM-Newton observations of the highly optically polarized broad absorption line quasar (BALQSO) CSO 755. By analyzing its X-ray spectrum with a total of approximately 3000 photons we find that this source has an X-ray continuum of "typical" radio-quiet quasars, with a photon index of Gamma=1.83, and a rather flat (X-ray bright) intrinsic optical-to-X-ray spectral slope of alpha_ox=- 1.51. The source shows evidence for intrinsic absorption, and fitting the spectrum with a neutral-absorption model gives a column density of N_H approximately 1.2x10^22 cm^{-2}; this is among the lowest X-ray columns measured for BALQSOs. We do not detect, with high significance, any other absorption features in the X-ray spectrum. Upper limits we place on the rest-frame equivalent width of a neutral (ionized) Fe K-alpha line, less than =180 eV (less than =120 eV), and on the Compton-reflection component parameter, R less than =0.2, suggest that most of the X-rays from the source are directly observed rather than being scattered or reflected; this is also supported by the relatively flat intrinsic alpha ox we measure. The possibility that most of the X-ray flux is scattered due to the high level of UV-optical polarization is ruled out. Considering data for 46 BALQSOs from the literature, including CSO 755, we have found that the UV-optical continuum polarization level of BALQSOs is not correlated with any of their X-ray properties. A lack of significant short-term and long-term X-ray flux variations in the source may be attributed to a large black-hole mass in CSO 755. We note that another luminous BALQSO, PG 2112+059, has both similar shallow C IV BALs and moderate X-ray absorption.

  5. Monitoring of PAHs in air by collection on XAD-2 adsorbent then microwave-assisted thermal desorption coupled with headspace solid-phase microextraction and gas chromatography with mass spectrometric detection.

    Science.gov (United States)

    Wei, Ming-Chi; Chang, Wan-Ting; Jen, Jen-Fon

    2007-02-01

    Microwave-assisted thermal desorption (MAD) coupled to headspace solid-phase microextraction (HS-SPME) has been studied for in-situ, one-step, sample preparation for PAHs collected on XAD-2 adsorbent, before gas chromatography with mass spectrometric detection. The PAHs on XAD-2 were desorbed into the extraction solution, evaporated into the headspace by use of microwave irradiation, and absorbed directly on a solid-phase microextraction fiber in the headspace. After desorption from the SPME fiber in the hot GC injection port, PAHs were analyzed by GC-MS. Conditions affecting extraction efficiency, for example extraction solution, addition of salt, stirring speed, SPME fiber coating, sampling temperature, microwave power and irradiation time, and desorption conditions were investigated. Experimental results indicated that extraction of 275 mg XAD-2, containing 10-200 ng PAHs, with 10-mL ethylene glycol-1 mol L(-1) NaCl solution, 7:3, by irradiation with 120 W for 40 min (the same as the extraction time), and collection with a PDMS-DVB fiber at 35 degrees C, resulted in the best extraction efficiency. Recovery was more than 80% and RSD was less than 14%. Optimum desorption was achieved by heating at 290 degrees C for 5 min. Detection limits varied from 0.02 to 1.0 ng for different PAHs. A real sample was obtained by using XAD-2 to collect smoke from indoor burning of joss sticks. The amounts of PAHs measured varied from 0.795 to 2.53 ng. The method is a simple and rapid procedure for determination of PAHs on XAD-2 absorbent, and is free from toxic organic solvents.

  6. Study on synchronous detection method of methane and ethane with laser absorption spectroscopy technology

    Science.gov (United States)

    He, Ying; Zhang, Yu-jun; You, Kun; Gao, Yan-wei; Chen, Chen; Liu, Jian-guo; Liu, Wen-qing

    2016-10-01

    The main ingredient of mash gas is alkenes, and methane is the most parts of mash gas and ethane is a small portion of it. Fast, accurate, real-time measurement of methane and ethane concentration is an important task for preventing coal mining disaster. In this research, a monitoring system with tunable diode laser absorption spectroscopy (TDLAS) technology has been set up for simultaneous measurement of methane and ethane, and a DFB laser at wavelength of 1.653μm was used as the laser source. The absorption spectroscopy information of methane and ethane, especially the characteristic of the spectrum peak positions and relative intensity were determined by available spectral structures from previous study and available database. Then, the concentration inversion algorithm method based on the spectral resolution and feature extraction was designed for methane and ethane synchronous detection. At last, the continuously experimental results obtained by different concentration of methane and ethane sample gases with the multiple reflection cell and the standard distribution system. In this experiment, the standard distribution system made with the standard gas and two high precision mass flow meters of D07 Sevenstar series whose flow velocity is 1l/min and 5l/min respectively. When the multiple reflection cell work stably, the biggest detection error of methane concentration inversion was 3.7%, and the biggest detection error of ethane was 4.8%. So it is verified that this concentration inversion algorithm works stably and reliably. Thus, this technology could realize the real-time, fast and continuous measurement requirement of mash gas and it will provide the effective technical support to coal mining production in safety for our country.

  7. GMRT Detection of HI 21cm Associated Absorption towards the = 1.2 Red Quasar 3C 190

    Indian Academy of Sciences (India)

    C. H. Ishwara-Chandra; K. S. Dwarakanath; K. R. Anantharamaiah

    2003-03-01

    We report the GMRT detection of associated HI 21 cm-line absorption in the = 1.1946 red quasar 3C 190. Most of the absorption is blue-shifted with respect to the systemic redshift. The absorption, at ∼ 647.7MHz, is broad and complex, spanning a velocity width of ∼ 600 kms-1. Since the core is self-absorbed at this frequency, the absorption is most likely towards the hotspots. Comparison of the radio and deep optical images reveal linear filaments in the optical which overlap with the brighter radio jet towards the south-west.We therefore suggest that most of the HI 21 cm-line absorption could be occurring in the atomic gas shocked by the south-west jet.

  8. Data correlation in on-line solid-phase extraction-gas chromatography-atomic emission/mass spectrometric detection of unknown microcontaminants

    NARCIS (Netherlands)

    Hankemeier, Th.; Rozenbrand, J.; Abhadur, M.; Vreuls, J.J.; Brinkman, U.A.Th.

    1998-01-01

    A procedure is described for the (non-target) screening of hetero-atom-containing compounds in tap and waste water by correlating data obtained by gas chromatography (GC) using atomic emission (AED) and mass selective (MS) detection. Solid-phase extraction (SPE) was coupled on-line to both GC system

  9. Use of an oxidative destruction and quadrupole mass spectrometric (QMS) detection for the determination of the organic elemental composition of suspended matter in surface water

    NARCIS (Netherlands)

    Reijnders, H.F.R.; Onderdelinden, D.; Visser, M.G.; Griepink, B.

    1980-01-01

    A study was made of the applicability of a system consisting of a combustion followed by QMS-detection for the determination of the elemental composition of organic matter suspended in surface water. The solid material obtained from several types of water was collected by centrifugation. The results

  10. The Azimuthal Dependence of Outflows and Accretion Detected Using OVI Absorption

    CERN Document Server

    Kacprzak, Glenn G; Churchill, Christopher W; Nielsen, Nikole M; Charlton, Jane C

    2015-01-01

    We report a bimodality in the azimuthal angle ($\\Phi$) distribution of gas around galaxies traced by OVI absorption. We present the mean $\\Phi$ probability distribution function of 29 HST-imaged OVI absorbing (EW>0.1A) and 24~non-absorbing (EW<0.1A) isolated galaxies (0.08absorption is azimuthally dependent and occurs between $\\pm10-20^{\\circ}$ of the galaxy projected major axis and within $\\pm30^{\\circ}$ of the projected minor axis. We find higher EWs along the projected minor axis with weaker EWs along the project major axis. Highly inclined galaxies have the lowest covering fractions due to minimized outflow/inflow cross-section geometry. Absorbing galaxies also have bluer colors while non-absorbers have redder colors, suggesting that star-formation is a key driver in the OVI detection rate. OVI surrou...

  11. Detection of the transient PNO molecule by infrared laser absorption spectroscopy

    Science.gov (United States)

    Bell, I. S.; Hamilton, P. A.; Davies, P. B.

    The PNO molecule has been observed in the gas phase for the first time. Some 200 vibrationrotation transitions were detected in the 1760cm-1 region using infrared diode laser absorption spectroscopy in a long path cell. Most of the lines can be assigned to the (001)←(000) stretching fundamental and (011)←(010) hot band transitions. The fundamental band exhibits a perturbation at high rotational levels which leads to a unique assignment of the rotational numbering. The effective rotational constants determined are in good agreement with ab initio predictions and the band origin, 1756.64586(24)cm-1, is very close to the matrix value. A tentative rotational assignment of the hot band transitions has been made which gives a band origin of 1748.388cm-1.

  12. Broadband magnetometry by infrared-absorption detection of diamond NV centers

    CERN Document Server

    Acosta, V M; Jarmola, A; Zipp, L J; Ledbetter, M P; Budker, D

    2010-01-01

    We demonstrate magnetometry by detection of the spin state of high-density nitrogen-vacancy (NV) ensembles in diamond using optical absorption at 1042 nm. With this technique, measurement contrast and collection efficiency can approach unity, leading to an increase in magnetic sensitivity compared to the more common method of collecting red fluorescence. Working at 75 K with a sensor with effective volume 50x50x300 microns^3, we project photon shot-noise limited sensitivity of 5 pT in one second of integration and bandwidth from DC to a few MHz. Operation in a gradiometer configuration is demonstrated with a sensitivity of 7 nT_{rms} in one second of integration at ~110 Hz bandwidth.

  13. Arsenic speciation in seafood samples with emphasis on minor constituents. An investigation by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

    1993-01-01

    Extracts of 11 samples of shrimp, crab, fish, fish liver, shellfish and lobster digestive gland (hepatopancreas), including five certified reference materials, were investigated for their contents of arsenic compounds (arsenic speciation). The cation-exchange high performance liquid chromatography...... procedure was optimized to separate six cationic arsenicals present in the samples with internal chromatographic standardization by the trimethylselenonium ion, which was detected a m/z 82 (Se-82), in addition to arsenic at m/z 75, by inductively coupled plasma mass spectrometry. The content of each species...... gland, and another unknown (U2) was present at 0.2-6.4% in all samples. The contents of arsenite and arsenate were 0-1.4%, dimethylarsinate 8.2-29% while monomethylarsonate was detected only in oyster at 0.3% of the total extracted arsenic. Finding tetramethylarsonium ion and arsenocholine in a variety...

  14. Speciation of eight arsenic compounds in human urine by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

    1993-01-01

    Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate...... and dimethylarsinate and the cations arsenobetaine, trimethylarsine oxide, arsenocholine and the tetramethylarsonium ion. Hexahydroxyantimonate(III) was co-chromatographed with the arsenic anions but detected at m/z 121 and used as an internal standard for their qualitative analysis. Arsenite was prone to oxidation...... to arsenate in urine but was stable after at least 4-fold dilution of the urine with water. Arsenite was unstable in both urine samples and standard mixtures when diluted with the basic (pH 10.3) mobile phase used for anion chromatography. This could not be prevented by adding ascorbic acid as antioxidant...

  15. Speciation of selenoamino acids, selenonium ions and inorganic selenium by ion exchange HPLC with mass spectrometric detection and its application to yeast and algae

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Hansen, M.; Fan, T.

    2001-01-01

    Cation and anion exchange HPLC were used to separate a mixture of 12 selenium species comprising selenoamino acids, selenonium ions and inorganic selenium. The cationic species were separated from each other and from the co-injected anions using a cation exchange column with gradient elution...... by aqueous pyridinium formate at pH similar to 3 as the mobile phase. The anionic species were separated using an anion exchange column with isocratic elution by an aqueous salicylate-TRIS mobile phase at pH 8.5. The separated selenium species were detected as Se-80 by ICP-dynamic reaction cell (DRC...... acid extract of Chlorella algae contained dimethylselenonium propionate (DMSeP), which was verified by HPLC-ES-MS. Se-allylselenocysteine and selenoethionine was detected at the low ng g(-1) concentration level based on co-chromatography with the standard substances spiked to the algal extract....

  16. Combining asymmetrical flow field-flow fractionation with light-scattering and inductively coupled plasma mass spectrometric detection for characterization of nanoclay used in biopolymer nanocomposites

    DEFF Research Database (Denmark)

    Schmidt, Bjørn; Petersen, Jens Højslev; Koch, C. Bender

    2009-01-01

    of polylactide (PLA) with 5% Cloisite®30B (a derivatized montmorillonite clay) as a filler. Based on AF4-MALS analyses, we found that particles ranging from 50 to 800 nm in radius indeed migrated into the 95% ethanol used as a food simulant. The full hyphenated AF4-MALS-ICP-MS system showed, however, that none...... of clay nanoparticulates, an analytical system combining asymmetrical flow field-flow fractionation (AF4) with multi-angle light-scattering detection (MALS) and inductively coupled plasma mass spectrometry (ICP-MS) is presented. In a migration study, we tested a biopolymer nanocomposite consisting...

  17. The use of ultra-high pressure liquid chromatography with tandem mass spectrometric detection in the analysis of agrochemical residues and mycotoxins in food - challenges and applications.

    Science.gov (United States)

    O'Mahony, John; Clarke, Lesa; Whelan, Michelle; O'Kennedy, Richard; Lehotay, Steven J; Danaher, Martin

    2013-05-31

    In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence of UHPLC through technological advances. The implications of this new chromatographic technology for MS detection are discussed, as well as some of the remaining challenges in exploiting it for chemical residue applications. Finally, a comprehensive overview of published applications of UHPLC-MS in food contaminant analysis is presented, with a particular focus on veterinary drug residues.

  18. Main differences between volatiles of sparkling and base wines accessed through comprehensive two dimensional gas chromatography with time-of-flight mass spectrometric detection and chemometric tools.

    Science.gov (United States)

    Welke, Juliane Elisa; Zanus, Mauro; Lazzarotto, Marcelo; Pulgati, Fernando Hepp; Zini, Cláudia Alcaraz

    2014-12-01

    The main changes in the volatile profile of base wines and their corresponding sparkling wines produced by traditional method were evaluated and investigated for the first time using headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) and chemometric tools. Fisher ratios helped to find the 119 analytes that were responsible for the main differences between base and sparkling wines and principal component analysis explained 93.1% of the total variance related to the selected 78 compounds. It was also possible to observe five subclusters in base wines and four subclusters in sparkling wines samples through hierarchical cluster analysis, which seemed to have an organised distribution according to the regions where the wines came from. Twenty of the most important volatile compounds co-eluted with other components and separation of some of them was possible due to GC×GC/TOFMS performance.

  19. Mass-spectrometric identification of binding proteins of Mr 25,000 protein, a part of vitellogenin B1, detected in particulate fraction of Xenopus laevis oocytes.

    Science.gov (United States)

    Sugimoto, Isamu; Li, Zhijun; Yoshitome, Satoshi; Ito, Susumu; Hashimoto, Eikichi

    2004-10-01

    A phosphorylated protein with molecular mass of 25,000 (pp25) is a component of Xenopus laevis vitellogenin B1. Our previous report showed the existence of several binding proteins of pp25 in the particulate fraction of Xenopus oocytes. In an attempt to elucidate the function of pp25, two of these binding proteins were purified, analyzed by mass-spectrometry, and identified as ribosomal proteins S13 and S14. Other binding proteins in the particulate fraction mostly corresponded to those derived from purified 40S and 60S ribosomal subunits, as shown by the overlay assay method. However, pp25 did not show any effect on protein synthesis in the rabbit reticulocyte lysate system. A model in which pp25 connects a type of serpin (serine protease inhibitor), the only pp25-binding protein detected in the cytoplasm, to the endoplasmic reticulum through two serine clusters is proposed to explain a possible function of this protein.

  20. A sensitive fluorescence reagent for the determination of aldehydes from alcoholic beverage using high-performance liquid chromatography with fluorescence detection and mass spectrometric identification

    Energy Technology Data Exchange (ETDEWEB)

    You Jinmao [Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001 (China)], E-mail: Jmyou6304@163.com; Yan Tao; Zhao Huaixin [Key Laboratory of Life-Organic Analysis, College of Chemistry Science, Qufu Normal University, Qufu Shandong 273165 (China); Sun Zhiwei; Xia Lian; Suo Yourui; Li Yulin [Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001 (China)

    2009-03-16

    A pre-column derivatization method for the sensitive determination of aldehydes using the tagging reagent 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl carbonylhydrazine (DBCEEC) followed by high-performance liquid chromatography with fluorescence detection and APCI-MS identification has been developed. The chromophore of fluoren-9-methoxy-carbonylhydrazine (Fmoc-hydrazine) reagent was replaced by 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl functional group, which resulted in a sensitive fluorescence tagging reagent DBCEEC. DBCEEC could easily and quickly labeled aldehydes. The maximum excitation (300 nm) and emission (400 nm) wavelengths did not essentially change for all the aldehyde derivatives. Derivatives were sufficiently stable to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z [M + (CH{sub 2}){sub n}]{sup +} in positive-ion mode (M: molecular weight of DBCEEC, n: corresponding aldehyde carbon atom numbers). The collision-induced dissociation of protonated molecular ion formed fragment ions at m/z 294.6, m/z 338.6 and m/z 356.5. Studies on derivatization demonstrated excellent derivative yields in the presence of trichloroacetic acid (TCA) catalyst. Maximal yields close to 100% were observed with a 10 to 15-fold molar reagent excess. Separation of the derivatized aldehydes had been optimized on ZORBAX Eclipse XDB-C{sub 8} column with aqueous acetonitrile as mobile phase in conjunction with a binary gradient elution. Excellent linear responses were observed at the concentration range of 0.01-10 nmol mL{sup -1} with coefficients of >0.9991. Detection limits obtained by the analysis of a derivatized standard containing 0.01 nmol mL{sup -1} of each aldehyde, were from 0.2 to 1.78 nmol L{sup -1} (at a signal-to-noise ratio of 3)

  1. Standoff detection of bioaerosols over wide area using a newly developed sensor combining a cloud mapper and a spectrometric LIF lidar

    Science.gov (United States)

    Buteau, Sylvie; Simard, Jean-Robert; Roy, Gilles; Lahaie, Pierre; Nadeau, Denis; Mathieu, Pierre

    2013-10-01

    A standoff sensor called BioSense was developed to demonstrate the capacity to map, track and classify bioaerosol clouds from a distant range and over wide area. The concept of the system is based on a two steps dynamic surveillance: 1) cloud detection using an infrared (IR) scanning cloud mapper and 2) cloud classification based on a staring ultraviolet (UV) Laser Induced Fluorescence (LIF) interrogation. The system can be operated either in an automatic surveillance mode or using manual intervention. The automatic surveillance operation includes several steps: mission planning, sensor deployment, background monitoring, surveillance, cloud detection, classification and finally alarm generation based on the classification result. One of the main challenges is the classification step which relies on a spectrally resolved UV LIF signature library. The construction of this library relies currently on in-chamber releases of various materials that are simultaneously characterized with the standoff sensor and referenced with point sensors such as Aerodynamic Particle Sizer® (APS). The system was tested at three different locations in order to evaluate its capacity to operate in diverse types of surroundings and various environmental conditions. The system showed generally good performances even though the troubleshooting of the system was not completed before initiating the Test and Evaluation (T&E) process. The standoff system performances appeared to be highly dependent on the type of challenges, on the climatic conditions and on the period of day. The real-time results combined with the experience acquired during the 2012 T & E allowed to identify future ameliorations and investigation avenues.

  2. Detection of Glucose with Atomic Absorption Spectroscopy by Using Oligonucleotide Functionalized Gold Nanoparticle.

    Science.gov (United States)

    Zhang, Hong; Yan, Honglian; Ling, Liansheng

    2016-06-01

    A novel method for the detection of glucose was established with atomic absorption spectroscopy by using the label of gold nanoparticle (AuNP). Silver-coated glass assembled with oligonucleotide 5'-SH-T12-AGA CAA GAG AGG-3' (Oligo 1) was acted as separation probe, oligonucleotide 5'-CAA CAG AGA ACG-T12-SH-3' modified gold nanoparticle (AuNP-Oligo 2) was acted as signal-reporting probe. Oligonucleotide 5'-CGT TCT CTG TTG CCT CTC TTG TCT-3' (Oligo 3) could hybridize with Oligo 1 on the surface of silver-coated glass and AuNP-Oligo 2, and free AuNP-Oligo 2 could be removed by rinsing with buffer. Hence the concentration of Oligo 3 was transformed into the concentration of gold element. In addition, Oligo 3 could be cleaved into DNA fragments by glucose, glucose oxidase and Fe(2+)-EDTA through Fenton reaction. Thereby the concentration of glucose could be transformed to the absorbance of gold element. Under the optimum conditions, the integrated absorbance decreased proportionally to the concentration of glucose over the range from 50.0 μM to 1.0 mM with a detection limit of 40.0 μM. Moreover, satisfactory result was obtained when the assay was used to determinate glucose in human serum.

  3. VLBI Detections of Parsec-Scale Nonthermal Jets in Radio-Loud Broad Absorption Line Quasars

    CERN Document Server

    Doi, Akihiro; Kono, Yusuke; Oyama, Tomoaki; Fujisawa, Kenta; Takaba, Hiroshi; Sudou, Hiroshi; Wakamatsu, Ken-ichi; Yamauchi, Aya; Murata, Yasuhiro; Mochizuki, Nanako; Wajima, Kiyoaki; Omodaka, Toshihiro; Nagayama, Takumi; Nakai, Naomasa; Sorai, Kazuo; Kawai, Eiji; Sekido, Mamoru; Koyama, Yasuhiro; Asano, Shoichiro; Uose, Hisao

    2009-01-01

    We conducted radio detection observations at 8.4 GHz for 22 radio-loud broad absorption line (BAL) quasars, selected from the Sloan Digital Sky Survey (SDSS) Third Data Release, by a very-long-baseline interferometry (VLBI) technique. The VLBI instrument we used was developed by the Optically ConnecTed Array for VLBI Exploration project (OCTAVE), which is operated as a subarray of the Japanese VLBI Network (JVN). We aimed at selecting BAL quasars with nonthermal jets suitable for measuring their orientation angles and ages by subsequent detailed VLBI imaging studies to evaluate two controversial issues of whether BAL quasars are viewed nearly edge-on, and of whether BAL quasars are in a short-lived evolutionary phase of quasar population. We detected 20 out of 22 sources using the OCTAVE baselines, implying brightness temperatures greater than 10^5 K, which presumably come from nonthermal jets. Hence, BAL outflows and nonthermal jets can be generated simultaneously in these central engines. We also found four...

  4. Comparative biotransformation and disposition studies of nabumetone in humans and minipigs using high-performance liquid chromatography with ultraviolet, fluorescence and mass spectrometric detection.

    Science.gov (United States)

    Nobilis, M; Kopecký, J; Kvetina, J; Svoboda, Z; Pour, M; Kunes, J; Holcapek, M; Kolárová, L

    2003-08-08

    The disposition of the non-steroidal anti-inflammatory drug (NSAID) nabumetone after a single oral dose administration of nabumetone tablets to humans and minipigs was investigated. Nabumetone is a prodrug, which is metabolized in the organism to the principal pharmacodynamically active metabolite -- 6-methoxy-2-naphthylacetic acid (6-MNA), and some other minor metabolites (carbonyl group reduction products, O-desmethylation products and their conjugates with glucuronic and sulphuric acids). Standards of the above-mentioned metabolites were prepared using simple synthetic procedures and their structures were confirmed by NMR and mass spectrometry. A simple HPLC method for the simultaneous determination of nabumetone, 6-MNA and the other metabolites was developed, validated and used for xenobiochemical and pharmacokinetic studies in humans and minipigs and for distribution studies in minipigs. Naproxen was chosen as the internal standard (I.S.), both UV (for higher concentrations) and fluorescence detection (for very low concentrations) were used. The identity of the nabumetone metabolites in biological samples was confirmed using HPLC-MS experiments. Pharmacokinetics of nabumetone, 6-MNA and 6-HNA (6-hydroxy-2-naphthylacetic acid) in human and minipig plasma was evaluated and compared. The concentration levels of nabumetone metabolites in urine, bile and synovial fluid were also evaluated.

  5. Characterization of binding and bioaccessibility of Cr in Cr-enriched yeast by sequential extraction followed by two-dimensional liquid chromatography with mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Kaewkhomdee, Nattikarn [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Angot (France); Mahidol University, Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Bangkok (Thailand); Mounicou, Sandra; Szpunar, Joanna [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Angot (France); Lobinski, Ryszard [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Angot (France); Warsaw University of Technology, Department of Analytical Chemistry, Warsaw (Poland); Shiowatana, Juwadee [Mahidol University, Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Bangkok (Thailand)

    2010-02-15

    Sequential extraction (water, Driselase, protease XIV) and extraction with simulated gastric and intestinal fluids were proposed to characterize the binding and the bioaccessibility of chromium in two commercial food supplements obtained by incorporation of this element into yeast. Chromium in Cr-enriched yeast was found to be hardly extractable with water, Driselase, or simulated gastric fluid (recoveries of approximately 10-20%), but proteolysis or gastrointestinal fluid digestion released more than half of the chromium present. Fractionation with size-exclusion chromatography with Cr-specific detection by inductively coupled plasma mass spectrometry (ICP MS) allowed the distinction of two fractions: one below approximately 1 kDa and one 1-5 kDa; they contained the entirety of the released Cr with proportions varying as a function of the extracting solution and the origin of sample. When collected and investigated by reversed-phase high-performance liquid chromatography-ICP MS, the low molecular mass fraction was found to release Cr(III), whereas the heavier one showed most of Cr bound in fairly stable hydrophobic complexes. However, an attempt of their identification by electrospray ionization MS/MS and matrix-assisted laser desorption ionization MS was not successful. (orig.)

  6. Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection.

    Science.gov (United States)

    Nakamoto, Akihiro; Nishida, Manami; Saito, Takeshi; Kishiyama, Izumi; Miyazaki, Shota; Murakami, Katsunori; Nagao, Masataka; Namura, Akira

    2010-02-19

    A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d(5) was used as an internal standard. The linear ranges were 0.01-5.0 microg mL(-1) for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 microg mL(-1) for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation > or = 0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 microg mL(-1) of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio > or = 3) in urine was 5 ng mL(-1) for MA and MDMA and 10 ng mL(-1) for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation.

  7. A sensitive gas chromatographic-tandem mass spectrometric method for detection of alkylating agents in water: application to acrylamide in drinking water, coffee and snuff.

    Science.gov (United States)

    Pérez, Hermes Licea; Osterman-Golkar, Siv

    2003-08-01

    A sensitive analytical method for the analysis of acrylamide and other electrophilic agents in water has been developed. The amino acid L-valine served as a nucleophilic trapping agent. The method was applied to the analysis of acrylamide in 0.2-1 mL samples of drinking water or Millipore-filtered water, brewed coffee, or water extracts of snuff. The reaction product, N-(2-carbamoylethyl)valine, was incubated with pentafluorophenyl isothiocyanate to give a pentafluorophenylthiohydantoin (PFPTH) derivative. This derivative was extracted with diethyl ether, separated from excess reagent and impurities by a simple extraction procedure, and analyzed by gas chromatography-tandem mass spectrometry. (2H3)Acrylamide, added before the reaction with L-valine, was used as internal standard. Acrylamide and the related compound, N-methylolacrylamide, gave the same PFPTH derivative. The concentrations of acrylamides were acrylamide L(-1)) in water, 200 to 350 nmol L(-1) in brewed coffee, and 10 to 34 nmol g(-1) snuff in portion bags, respectively. The precision (the coefficient of variation was 5%) and accuracy of the method were good. The detection limit was considerably lower than that of previously published methods for the analysis of acrylamide.

  8. Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Akihiro [Scientific Investigation Laboratory, Hiroshima Prefectural Police Headquarters, Kohnan 2-26-3, Naka-ku, Hiroshima 730-0825 (Japan); Nishida, Manami [Hiroshima University Technical Center, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan); Saito, Takeshi [Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1143 (Japan); Kishiyama, Izumi; Miyazaki, Shota [GL Sciences Inc., Sayamagahara 237-2, Iruma, Saitama 358-0032 (Japan); Murakami, Katsunori [Scientific Investigation Laboratory, Hiroshima Prefectural Police Headquarters, Kohnan 2-26-3, Naka-ku, Hiroshima 730-0825 (Japan); Nagao, Masataka [Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan); Namura, Akira, E-mail: namera@hiroshima-u.ac.jp [Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan)

    2010-02-19

    A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d{sub 5} was used as an internal standard. The linear ranges were 0.01-5.0 {mu}g mL{sup -1} for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 {mu}g mL{sup -1} for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation {>=}0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 {mu}g mL{sup -1} of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio {>=} 3) in urine was 5 ng mL{sup -1} for MA and MDMA and 10 ng mL{sup -1} for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation.

  9. Cloud point extraction of copper, lead, cadmium, and iron using 2,6-diamino-4-phenyl-1,3,5-triazine and nonionic surfactant, and their flame atomic absorption spectrometric determination in water and canned food samples.

    Science.gov (United States)

    Citak, Demirhan; Tuzen, Mustafa

    2012-01-01

    A cloud point extraction procedure was optimized for the separation and preconcentration of lead(II), cadmium(II), copper(II), and iron(III) ions in various water and canned food samples. The metal ions formed complexes with 2,6-diamino-4-phenyl-1,3,5-triazine that were extracted by surfactant-rich phases in the nonionic surfactant Triton X-114. The surfactant-rich phase was diluted with 1 M HNO3 in methanol prior to its analysis by flame atomic absorption spectrometry. The parameters affecting the extraction efficiency of the proposed method, such as sample pH, complexing agent concentration, surfactant concentration, temperature, and incubation time, were optimized. LOD values based on three times the SD of the blank (3Sb) were 0.38, 0.48, 1.33, and 1.85 microg/L for cadmium(II), copper(II), lead(II), and iron(III) ions, respectively. The precision (RSD) of the method was in the 1.86-3.06% range (n=7). Validation of the procedure was carried out by analysis of National Institute of Standards and Technology Standard Reference Material (NIST-SRM) 1568a Rice Flour and GBW 07605 Tea. The method was applied to water and canned food samples for determination of metal ions.

  10. Electrothermal atomic absorption spectrometric determination of vanadium in extracts of soil and sewage sludge certified reference materials after fractionation by means of the Communities Bureau of Reference modified sequential extraction procedure

    Science.gov (United States)

    Žemberyová, M.; Jankovič, R.; Hagarová, I.; Kuss, H.-M.

    2007-05-01

    A modified three-step sequential extraction procedure proposed by the Commission of European Communities Bureau of Reference (BCR) was applied to certified reference materials of three different soil groups (rendzina, luvisol, cambisol) and sewage sludge of different composition originating from a municipal water treatment plant in order to assess potential mobility and the distribution of vanadium in the resulting fractions. Analysis of the extracts was carried out by electrothermal atomic absorption spectrometry with Zeeman background correction using transversely heated graphite atomizers. Extracts showed significant matrix interferences which were overcome by the standard addition technique. The original soil and sludge certified reference materials (CRMs) and the extraction residue from the sequential extraction were decomposed by a mixture of HNO 3-HClO 4-HF in an open system. The content of V determined after decomposition of the samples was in very good agreement with the certified total values. The accuracy of the sequential extraction procedure was checked by comparing the sum of the vanadium contents in the three fractions and in the extraction residue with the certified total content of V. The amounts of vanadium leached were in good correlation with the certified total contents of V in the CRMs of soils and sewage sludge. In the soils examined, vanadium was present almost entirely in the mineral lattice, while in the sewage sludge samples 9-14% was found in the oxidizable and almost 25% in the reducible fractions. The recovery ranged from 93-106% and the precision (RSD) was below 10%.

  11. Stability of arsenic peptides in plant extracts: off-line versus on-line parallel elemental and molecular mass spectrometric detection for liquid chromatographic separation.

    Science.gov (United States)

    Bluemlein, Katharina; Raab, Andrea; Feldmann, Jörg

    2009-01-01

    The instability of metal and metalloid complexes during analytical processes has always been an issue of an uncertainty regarding their speciation in plant extracts. Two different speciation protocols were compared regarding the analysis of arsenic phytochelatin (As(III)PC) complexes in fresh plant material. As the final step for separation/detection both methods used RP-HPLC simultaneously coupled to ICP-MS and ES-MS. However, one method was the often used off-line approach using two-dimensional separation, i.e. a pre-cleaning step using size-exclusion chromatography with subsequent fraction collection and freeze-drying prior to the analysis using RP-HPLC-ICP-MS and/or ES-MS. This approach revealed that less than 2% of the total arsenic was bound to peptides such as phytochelatins in the root extract of an arsenate exposed Thunbergia alata, whereas the direct on-line method showed that 83% of arsenic was bound to peptides, mainly as As(III)PC(3) and (GS)As(III)PC(2). Key analytical factors were identified which destabilise the As(III)PCs. The low pH of the mobile phase (0.1% formic acid) using RP-HPLC-ICP-MS/ES-MS stabilises the arsenic peptide complexes in the plant extract as well as the free peptide concentration, as shown by the kinetic disintegration study of the model compound As(III)(GS)(3) at pH 2.2 and 3.8. But only short half-lives of only a few hours were determined for the arsenic glutathione complex. Although As(III)PC(3) showed a ten times higher half-life (23 h) in a plant extract, the pre-cleaning step with subsequent fractionation in a mobile phase of pH 5.6 contributes to the destabilisation of the arsenic peptides in the off-line method. Furthermore, it was found that during a freeze-drying process more than 90% of an As(III)PC(3) complex and smaller free peptides such as PC(2) and PC(3) can be lost. Although the two-dimensional off-line method has been used successfully for other metal complexes, it is concluded here that the fractionation and

  12. Herschel observations of Extra-Ordinary Sources (HEXOS) : Detection of hydrogen fluoride in absorption towards Orion KL

    NARCIS (Netherlands)

    Phillips, T. G.; Bergin, E. A.; Lis, D. C.; Neufeld, D. A.; Bell, T. A.; Wang, S.; Crockett, N. R.; Emprechtinger, M.; Blake, G.A.; Caux, E.; Ceccarelli, C.; Cernicharo, J.; Comito, C.; Daniel, F.; Dubernet, M. -L; Encrenaz, P.; Gerin, M.; Giesen, T. F.; Goicoechea, J. R.; Goldsmith, P. F.; Herbst, E.; Joblin, C.; Johnstone, D.; Langer, W. D.; Latter, W. D.; Lord, S. D.; Maret, S.; Martin, P. G.; Melnick, G. J.; Menten, K. M.; Morris, P.; Müller, H.S.P.; Murphy, J. A.; Ossenkopf, V.; Pearson, J. C.; Pérault, M.; Plume, R.; Qin, S.-L; Schilke, P.; Schlemmer, S.; Stutzki, J.; Trappe, N.; van der Tak, F. F. S.; Vastel, C.; Yorke, H. W.; Yu, S.; Zmuidzinas, J.; Boogert, A.; Güsten, R.; Hartogh, P.; Honingh, N.; Karpov, A.; Kooi, J.; Krieg, J. -M; Schieder, R.

    2010-01-01

    We report a detection of the fundamental rotational transition of hydrogen fluoride in absorption towards Orion KL using Herschel/HIFI. After the removal of contaminating features associated with common molecules (“weeds”), the HF spectrum shows a P-Cygni profile, with weak redshifted emission and s

  13. Detection of ocean glint and ozone absorption using LCROSS Earth observations

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Tyler D. [NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 (United States); Ennico, Kimberly [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Meadows, Victoria S.; Sparks, William; Schwieterman, Edward W. [NASA Astrobiology Institute' s Virtual Planetary Laboratory, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Bussey, D. Ben J. [NASA Ames Research Center, MS 17-1, Moffett Field, CA 94089, USA Now the NASA Solar System Exploration Research Virtual Institute. (United States); Breiner, Jonathan, E-mail: tyler.d.robinson@nasa.gov [Astronomy Department, University of Washington, Seattle, WA 98195 (United States)

    2014-06-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 μm (λ/Δλ ∼ 500) and 1.17-2.48 μm (λ/Δλ ∼ 50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ∼10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase data set, which is well matched by our model predictions throughout the observed wavelength range. This provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths, where the glint signal is strongest. We examine the detection of the ozone 255 nm Hartley and 400-700 nm Chappuis bands. While the Hartley band is the strongest ozone feature in Earth's spectrum, false positives for its detection could exist. Finally, we discuss the implications of these findings for future exoplanet characterization missions.

  14. Two-Dimensional UV Absorption Correlation Spectroscopy as a Method for the Detection of Thiamethoxam Residue in Tea

    Science.gov (United States)

    Zhang, J.; Zhao, Zh.; Wang, L.; Zhu, X.; Shen, L.; Yu, Y.

    2015-05-01

    Two-dimensional correlation spectroscopy (2D-COS) combined with UV absorption spectroscopy was evaluated as a technique for the identification of spectral regions associated with the residues of thiamethoxam in tea. There is only one absorption peak at 275 nm in the absorption spectrum of a mixture of thiamethoxam and tea, which is the absorption peak of tea. Based on 2D-COS, the absorption peak of thiamethoxam at 250 nm is extracted from the UV spectra of the mixture. To determine the residue of thiamethoxam in tea, 250 nm is selected as the measured wavelength, at which the fitting result is as follows: the residual sum of squares is 0.01375, standard deviation R2 is 0.99068, and F value is 426. Statistical analysis shows that there is a significant linear relationship between the concentration of thiamethoxam in tea and the absorbance at 250 nm in the UV spectra of the mixture. Moreover, the average prediction error is 0.0033 and the prediction variance is 0.1654, indicating good predictive result. Thus, the UV absorption spectrum can be used as a measurement method for rapid detection of thiamethoxam residues in tea.

  15. Detection of 21 Centimeter HI Absorption at z = 0.78 in a Survey of Radio Continuum Sources

    CERN Document Server

    Darling, J; Haynes, M P; Bolatto, A D; Bower, G C; Darling, Jeremy; Giovanelli, Riccardo; Haynes, Martha P.; Bolatto, Alberto D.; Bower, Geoffrey C.

    2004-01-01

    We report the detection of a deep broad HI 21 cm absorption system at z = 0.78 toward the radio source [HB89] 2351+456 (4C+45.51) at z = 1.992. The HI absorption was identified in a blind spectral line survey conducted at the Green Bank Telescope spanning 0.63 8.5 K, this system is by definition a damped Ly alpha absorption system (N(HI) >= 2 x 10^20 cm^-2). The line is unusually broad, with a FWHM of 53 km/s and a full span of 163 km/s, suggesting a physically extended HI gas structure. Radio surveys identify damped Ly alpha systems in a manner that bypasses many of the selection effects present in optical/UV surveys, including dust extinction and the atmospheric cutoff for z < 1.65. The smooth broad profile of this HI 21 cm absorption system is similar to the z = 0.89 HI absorption toward PKS 1830-211, which suggests that the absorber toward [HB89] 2351+456 is also a gravitational lens and a molecular absorption system. However, very long baseline interferometry and Hubble Space Telescope observations s...

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

    Science.gov (United States)

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

    2005-05-01

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

  17. Herschel observations of EXtra-Ordinary Sources (HEXOS) : Detecting spiral arm clouds by CH absorption lines

    NARCIS (Netherlands)

    Qin, S.-L; Schilke, P.; Comito, C.; Möller, T.; Rolffs, R.; Müller, H.S.P.; Belloche, A.; Menten, K. M.; Lis, D. C.; Phillips, T. G.; Bergin, E. A.; Bell, T. A.; Crockett, N. R.; Blake, G.A.; Cabrit, S.; Caux, E.; Ceccarelli, C.; Cernicharo, J.; Daniel, F.; Dubernet, M. -L; Emprechtinger, M.; Encrenaz, P.; Falgarone, E.; Gerin, M.; Giesen, T. F.; Goicoechea, J. R.; Goldsmith, P. F.; Gupta, H.; Herbst, E.; Joblin, C.; Johnstone, D.; Langer, W. D.; Lord, S. D.; Maret, S.; Martin, P. G.; Melnick, G. J.; Morris, P.; Murphy, J. A.; Neufeld, D. A.; Ossenkopf, V.; Pagani, L.; Pearson, J. C.; Pérault, M.; Plume, R.; Salez, M.; Schlemmer, S.; Stutzki, J.; Trappe, N.; van der Tak, F. F. S.; Vastel, C.; Wang, S.; Yorke, H. W.; Yu, S.; Zmuidzinas, J.; Boogert, A.; Güsten, R.; Hartogh, P.; Honingh, N.; Karpov, A.; Kooi, J.; Krieg, J. -M; Schieder, R.; Diez-Gonzalez, M. C.; Bachiller, R.; Martin-Pintado, J.; Baechtold, W.; Olberg, M.; Nordh, L. H.; Gill, J. L.; Chattopadhyay, G.

    2010-01-01

    We have observed CH absorption lines (J = 3/2, N = 1 ≤ftarrow J = 1/2, N = 1) against the continuum source Sgr B2(M) using the Herschel/HIFI instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities and line

  18. Flame atomic absorption spectrometric determination of copper, zinc and manganese after solid-phase extraction using 2,6-dichlorophenyl-3,3-bis(indolyl)methane loaded on Amberlite XAD-16.

    Science.gov (United States)

    Ghaedi, M; Niknam, K; Taheri, K; Hossainian, H; Soylak, M

    2010-03-01

    A simple and selective method for the determination of Cu(2+), Zn(2+) and Mn(2+) ions in real samples by FAAS after solid-phase extraction was developed. The method is based on the sorption of metal ions on Amberlite XAD-16 modified by 3-((2,6-dichlorophenyl)(1H-indol-3-yl)methyl)-1H-indole (DCPIMI) at a pH of 5.0. The metal ions retained on solid phase by complexation with ligand were then eluted with 6 mL of 4 mol L(-1) nitric acid in acetone. In order to obtain a reversible uptake and elution of metal ions, the influence of flow rates of eluent and sample solution, ligand concentration and amount of surfactant and condition of elution solution was also investigated. A preconcentration factor of 225 was achieved by passing 1350 mL of sample through the solid phase, while the limit of detection (LOD) of Cu(2+), Zn(2+) and Mn(2+) ions were found to be 1.9, 1.5 and 2.6 ng mL(-1), respectively, and the corresponding precision at 20 microg L(-1) was 2.1%, 2.3%, 3.0%.

  19. DETECTION OF MOLECULAR ABSORPTION IN THE DAYSIDE OF EXOPLANET 51 PEGASI b?

    Energy Technology Data Exchange (ETDEWEB)

    Brogi, M.; Snellen, I. A. G.; Birkby, J. L. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); De Kok, R. J. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Albrecht, S. [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); De Mooij, E. J. W., E-mail: brogi@strw.leidenuniv.nl [Department of Astronomy and Astrophysics, University of Toronto, 50 St George Street, Toronto, ON M5S 3H4 (Canada)

    2013-04-10

    In this paper, we present ground-based high-resolution spectroscopy of 51 Pegasi using CRIRES at the Very Large Telescope. The system was observed for 3 Multiplication-Sign 5 hr at 2.3 {mu}m at a spectral resolution of R = 100,000, targeting potential signatures from carbon monoxide, water vapor, and methane in the planet's dayside spectrum. In the first 2 Multiplication-Sign 5 hr of data, we find a combined signal from carbon monoxide and water in absorption at a formal 5.9{sigma} confidence level, indicating a non-inverted atmosphere. We derive a planet mass of M{sub P} = (0.46 {+-} 0.02)M{sub Jup} and an orbital inclination i between 79. Degree-Sign 6 and 82. Degree-Sign 2, with the upper limit set by the non-detection of the planet transit in previous photometric monitoring. However, there is no trace of the signal in the final five hours of data. A statistical analysis indicates that the signal from the first two nights is robust, but we find no compelling explanation for its absence in the final night. The latter suffers from stronger noise residuals and greater instrumental instability than the first two nights, but these cannot fully account for the missing signal. It is possible that the integrated dayside emission from 51 Peg b is instead strongly affected by weather. However, more data are required before we can claim any time variability in the planet's atmosphere.

  20. A Nano-Biosensor for DNA Sequence Detection Using Absorption Spectra of SWNT-DNA Composite

    Directory of Open Access Journals (Sweden)

    J. Bansal

    2011-01-01

    Full Text Available A biosensor based on Single Walled Carbon Nanotube (SWNT-Poly (GTn ssDNA hybrid has been developed for medical diagnostics. The absorption spectrum of this assay is determined with the help of a Shimadzu UV-VIS-NIR spectrophotometer. Two distinct bands each containing three peaks corresponding to first and second van Hove singularities in the density of states of the nanotubes were observed in the absorption spectrum. When a single-stranded DNA (ssDNA having a sequence complementary to probic DNA is added to the ssDNA-SWNT conjugates, hybridization takes place, which causes the red shift of absorption spectrum of nanotubes. On the other hand, when the DNA is noncomplementary, no shift in the absorption spectrum occurs since hybridization between the DNA and probe does not take place. The red shifting of the spectrum is considered to be due to change in the dielectric environment around nanotubes.

  1. Speciation of four selenium compounds using high performance liquid chromatography with on-line detection by inductively coupled plasma mass spectrometry or flame atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Pedersen, Gitte Alsing; Larsen, Erik Huusfeldt

    1997-01-01

    spectrometry (ICP-MS). The signal-to-noise ratio of the FAAS detector was optimized using a hydrogen-argon entrained-air flame and a slotted-tube atom trap (STAT) in the flame. The limit of detection (3 sigma) achieved by the HPLC-FAAS system was 1 mg L-1 of selenium (100 mu L injections) for each of the four......An analytical method for the speciation of selenomethionine, selenocystine, selenite and selenate by high performance liquid chromatography (HPLC) with atomic spectrometric detection is presented. An organic polymeric strong anion exchange column was used as the stationary phase in combination...... of 1300 W. The limit of detection achieved under these conditions was 1 mu g L-1 (100 mu L injections). The HPLC-ICP-MS system was used for selenium speciation of selenite and selenate in aqueous solutions during a BCR certification exercise and for selenium speciation in the certified reference material...

  2. Research on the sensitivity for the coal mine gas concentration detection by laser spectrum absorption

    Institute of Scientific and Technical Information of China (English)

    ZHOU Meng-ran; LI Zhen-bi

    2007-01-01

    Because of the former gas chemistry examination method defects, tunable diode laser absorption spectrum technology (TDLAS) was used. Itused an isolated absorption spectrum of the gas molecule to measure the gas absorption spectrum in order to distinguish the gas conveniently. The second harmonic (2f) was measured in this system.Due to the fact which the harmonious signal is proportional to the concentration of the absorption gas, the gas concentration may be obtained through examining harmonious signal. The theoretical analysis and the experimental result indicate that under the same level of pressure, survey with the signal-to-noise ratio(SNR) of 2f signal increases the accuracy by one order of magnitude and may reach 10-3 and the sensitivity may reach the 10-6 level compared to that of direct absorption. 5% methane density and a 30 cm absorption cell were used in the experiment. It has several advantages including high sensitivity, best resolution, and faster response and so on. The gas concentration monitoring ofcoal mine may be accomplished.

  3. Mass Spectrometric Method for Analyzing Metabolites in Yeast with Single Cell Sensitivity

    NARCIS (Netherlands)

    Amantonico, Andrea; Oh, Joo Yeon; Sobek, Jens; Heinemann, Matthias; Zenobi, Renato

    2008-01-01

    Getting a look-in: An optimized MALDI-MS procedure has been developed to detect endogenous primary metabolites directly in the cell extract. A detection limit corresponding to metabolites from less than a single cell has been attained, opening the door to single-cell metabolomics by mass spectrometr

  4. Detection of HO2 in an atmospheric pressure plasma jet using optical feedback cavity-enhanced absorption spectroscopy

    Science.gov (United States)

    Gianella, Michele; Reuter, Stephan; Lawry Aguila, Ana; Ritchie, Grant A. D.; van Helden, Jean-Pierre H.

    2016-11-01

    Cold non-equilibrium atmospheric pressure plasma jets are increasingly applied in material processing and plasma medicine. However, their small dimensions make diagnosing the fluxes of generated species a challenge. Here we report on the detection of the hydroperoxyl radical, HO2, in the effluent of a plasma jet by the use of optical feedback cavity-enhanced absorption spectroscopy. The spectrometer has a minimum detectable absorption coefficient {α }\\min of 2.25× {10}-10 cm-1 with a 100 second acquisition, equivalent to 5.5× {10}12 {{cm}}-3 of HO2 (under ideal conditions). Concentrations in the range of (3.1-7.8) × 1013 cm-3 were inferred in the 4 mm wide effluent of the plasma jet.

  5. Detection of hydrogen fluoride absorption in diffuse molecular clouds with Herschel/HIFI: a ubiquitous tracer of molecular gas

    CERN Document Server

    Sonnentrucker, P; Phillips, T G; Gerin, M; Lis, D C; De Luca, M; Goicoechea, J R; Black, J H; Bell, T A; Boulanger, F; Cernicharo, J; Coutens, A; Dartois, E; Kazmierczak, M; Encrenaz, P; Falgarone, E; Geballe, T R; Giesen, T; Godard, B; Goldsmith, P F; Gry, C; Gupta, H; Hennebelle, P; Herbst, E; Hily-Blant, P; Joblin, C; Kolos, R; Krelowski, J; Mart\\in-Pintado, J; Menten, K M; Monje, R; Mookerjea, B; Pearson, J; Perault, M; Persson, C M; Plume, R; Salez, M; Schlemmer, S; Schmidt, M; Stutzki, J; Teyssier, D; Vastel, C; Yu, S; Caux, E; Gusten, R; Hatch, W A; Klein, T; Mehdi, I; Morris, P; Ward, J S

    2010-01-01

    We discuss the detection of absorption by interstellar hydrogen fluoride (HF) along the sight line to the submillimeter continuum sources W49N and W51. We have used Herschel's HIFI instrument in dual beam switch mode to observe the 1232.4762 GHz J = 1 - 0 HF transition in the upper sideband of the band 5a receiver. We detected foreground absorption by HF toward both sources over a wide range of velocities. Optically thin absorption components were detected on both sight lines, allowing us to measure - as opposed to obtain a lower limit on - the column density of HF for the first time. As in previous observations of HF toward the source G10.6-0.4, the derived HF column density is typically comparable to that of water vapor, even though the elemental abundance of oxygen is greater than that of fluorine by four orders of magnitude. We used the rather uncertain N(CH)-N(H2) relationship derived previously toward diffuse molecular clouds to infer the molecular hydrogen column density in the clouds exhibiting HF abs...

  6. Near-infrared diode laser based spectroscopic detection of ammonia: a comparative study of photoacoustic and direct optical absorption methods

    Science.gov (United States)

    Bozoki, Zoltan; Mohacsi, Arpad; Szabo, Gabor; Bor, Zsolt; Erdelyi, Miklos; Chen, Weidong; Tittel, Frank K.

    2002-01-01

    A photoacoustic spectroscopic (PAS) and a direct optical absorption spectroscopic (OAS) gas sensor, both using continuous-wave room-temperature diode lasers operating at 1531.8 nm, were compared on the basis of ammonia detection. Excellent linear correlation between the detector signals of the two systems was found. Although the physical properties and the mode of operation of both sensors were significantly different, their performances were found to be remarkably similar, with a sub-ppm level minimum detectable concentration of ammonia and a fast response time in the range of a few minutes.

  7. Can Ground-based Telescopes Detect The Oxygen 1.27 Micron Absorption Feature as a Biomarker in Exoplanets ?

    CERN Document Server

    Kawahara, Hajime; Takami, Michihiro; Fujii, Yuka; Kotani, Takayuki; Murakami, Naoshi; Tamura, Motohide; Guyon, Olivier

    2012-01-01

    The oxygen absorption line imprinted in the scattered light from the Earth-like planets has been considered as the most promising metabolic biomarker of the exo-life. We examine the feasibility of the detection of the oxygen 1.27 micron band from habitable exoplanets, in particular, around late-type stars with a 30 m class ground-based telescope with a future instrument. We analyzed the night airglow around 1.27 micron with IRCS/echelle spectrometer on Subaru and found that the strong telluric emission from atmospheric oxygen molecules declines by an order of magnitude by the midnight. With compilation of nearby star catalogues combined with the sky background model, we estimate the detectability of the oxygen absorption band from an Earth twin, if exists, around nearby stars. We find that the most dominant photon noise of the oxygen 1.27 micron detection comes from the night airglow if the leakage is suppressed enough to detect the planet. We conclude that the future detectors for which the detection contras...

  8. HST hot Jupiter Transmission Spectral Survey: A detection of Na and strong optical absorption in HAT-P-1b

    CERN Document Server

    Nikolov, N; Pont, F; Burrows, A S; Fortney, J J; Ballester, G E; Evans, T M; Huitson, C M; Wakeford, H R; Wilson, P A; Aigrain, S; Deming, D; Gibson, N P; Henry, G W; Knutson, H; Etangs, A Lecavelier des; Showman, A P; Vidal-Madjar, A; Zahnle, K

    2013-01-01

    We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on HST observations, covering the spectral regime from 0.29 to 1.027{\\mu}m with STIS, which is coupled with a recent WFC3 transit (1.087 to 1.687{\\mu}m). We derive refined physical parameters of the HAT-P-1 system, including an improved orbital ephemeris. The transmission spectrum shows a strong absorption signature shortward of 0.55{\\mu}m, with a strong blueward slope into the near-ultraviolet. We detect atmospheric sodium absorption at a 3.3{\\sigma} significance level, but find no evidence for the potassium feature. The red data implies a marginally flat spectrum with a tentative absorption enhancement at wavelength longer than ~0.85{\\mu}m. The STIS and WFC3 spectra differ significantly in absolute radius level (4.3 +/- 1.6 pressure scale heights), implying strong optical absorption in the atmosphere of HAT-P-1b. The optical to near-infrared difference cannot be explained by stellar activity, as simulta- neous st...

  9. Herschel observations of extra-ordinary sources: Detection of Hydrogen Fluoride in absorption towards Orion~KL

    CERN Document Server

    Phillips, T G; Lis, D C; Neufeld, D A; Bell, T A; Wang, S; Crockett, N R; Emprechtinger, M; Blake, G A; Caux, E; Ceccarelli, C; Cernicharo, J; Comito, C; Daniel, F; Dubernet, M -L; Encrenaz, P; Gerin, M; Giesen, T F; Goicoechea, J R; Goldsmith, P F; Herbst, E; Joblin, C; Johnstone, D; Langer, W D; Latter, W D; Lord, S D; Maret, S; Martin, P G; Melnick, G J; Menten, K M; Morris, P; Muller, H S P; Murphy, J A; Ossenkopf, V; Pearson, J C; Perault, M; Plume, R; Qin, S -L; Schilke, P; Schlemmer, S; Stutzki, J; Trappe, N; van der Tak, F F S; Vastel, C; Yorke, H W; Yu, S; Zmuidzinas, J; Boogert, A; Gusten, R; Hartogh, P; Honingh, N; Karpov, A; Kooi, J; Krieg, J -M; Schieder, R

    2010-01-01

    We report a detection of the fundamental rotational transition of hydrogen fluoride in absorption towards Orion KL using Herschel/HIFI. After the removal of contaminating features associated with common molecules ("weeds"), the HF spectrum shows a P-Cygni profile, with weak redshifted emission and strong blue-shifted absorption, associated with the low-velocity molecular outflow. We derive an estimate of 2.9 x 10^13 cm^-2 for the HF column density responsible for the broad absorption component. Using our best estimate of the H2 column density within the low-velocity molecular outflow, we obtain a lower limit of ~1.6 x 10^-10 for the HF abundance relative to hydrogen nuclei, corresponding to 0.6% of the solar abundance of fluorine. This value is close to that inferred from previous ISO observations of HF J=2--1 absorption towards Sgr B2, but is in sharp contrast to the lower limit of 6 x 10^-9 derived by Neufeld et al. (2010) for cold, foreground clouds on the line of sight towards G10.6-0.4.

  10. Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bartnik, A.; Wachulak, P.; Fiedorowicz, H.; Fok, T.; Jarocki, R.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

    2013-11-15

    In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUV radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.

  11. Detection of hydrogen peroxide based on long-path absorption spectroscopy using a CW EC-QCL

    Science.gov (United States)

    Sanchez, N. P.; Yu, Y.; Dong, L.; Griffin, R.; Tittel, F. K.

    2016-02-01

    A sensor system based on a CW EC-QCL (mode-hop-free range 1225-1285 cm-1) coupled with long-path absorption spectroscopy was developed for the monitoring of gas-phase hydrogen peroxide (H2O2) using an interference-free absorption line located at 1234.055 cm-1. Wavelength modulation spectroscopy (WMS) with second harmonic detection was implemented for data processing. Optimum levels of pressure and modulation amplitude of the sensor system led to a minimum detection limit (MDL) of 25 ppb using an integration time of 280 sec. The selected absorption line for H2O2, which exhibits no interference from H2O, makes this sensor system suitable for sensitive and selective monitoring of H2O2 levels in decontamination and sterilization processes based on Vapor Phase Hydrogen Peroxide (VPHP) units, in which a mixture of H2O and H2O2 is generated. Furthermore, continuous realtime monitoring of H2O2 concentrations in industrial facilities employing this species can be achieved with this sensing system in order to evaluate average permissible exposure levels (PELs) and potential exceedances of guidelines established by the US Occupational Safety and Health Administration for H2O2.

  12. Label-free assay for the detection of glucose mediated by the effects of narrowband absorption on quantum dot photoluminescence

    Science.gov (United States)

    Khan, Saara A.; Smith, Gennifer T.; Ellerbee, Audrey K.

    2014-03-01

    We present a novel strategy for label-free detection of glucose based on CdSe/ZnS core/shell quantum dots (QDs). We exploit the concentration-dependent, narrowband absorption of the hexokinase-glucose 6-phosphate dehydrogenase enzymatic assay to selectively filter a 365-nm excitation source, leading to a proportional decrease in the photoluminescence intensity of the QDs. The visible wavelength emission of the QDs enables quantitative readout using standard visible detectors (e.g., CCD). Experimental results show highly linear QD photoluminescence over the clinically relevant glucose concentration range of 1-25mM, in excellent agreement with detection methods demonstrated by others. The method has a demonstrated limit of detection of 3.5μM, also on par with the best proposed methods. A significant advantage of our strategy is the complete elimination of QDs as a consumable. In contrast with other methods of QD-based measurement of glucose, our system does not require the glucose solution to be mixed with the QDs, thereby decreasing its overall cost and making it an ideal strategy for point-of-care detection of glucose in low-resource areas. Furthermore, readout can be accomplished with low-cost, portable detectors such as cellular phones, eliminating the need for expensive and bulky spectrophotometers to output quantitative information. The general strategy we present is useful for other biosensing applications involving chemistries with unique absorption peaks falling within the excitation band of available QDs.

  13. Inability to detect significant absorption of immunoreactive soya protein in healthy adults may be relevant to its weak allergenicity

    DEFF Research Database (Denmark)

    Lund, Cecilia M; Dirks, Christina G; Pedersen, Mona H

    2013-01-01

    ABSTRACT: Soya and peanut are botanically closely related and share cross-reacting antigens, but compared to soya, peanut allergy has a higher prevalence with more severe allergic reactions. Furthermore, the threshold dose for eliciting reactions is higher for soya. A difference in undigested...... protein absorption between the two foods, might explain this diversity.In the current study the amount of soya protein absorbed after soya bean ingestion in healthy adults was estimated. Ten subjects ingested 100 grams of soya beans (40 grams of soya protein) and blood was drawn before and 1, 3 and 24...... hours after administration. Serum was analysed by ELISA and histamine release (HR). In all serum samples the soya protein concentration was below quantification limit (1.6 ng/ml which corresponds to 4.8 mug or 0.12 parts per million absorbed soya protein.We could not detect any significant absorption...

  14. Airborne Laser Absorption Spectrometer Measurements of CO2 Column Mixing Ratios: Source and Sink Detection in the Atmospheric Environment

    Directory of Open Access Journals (Sweden)

    Menzies Robert T.

    2016-01-01

    Full Text Available The JPL airborne Laser Absorption Spectrometer instrument has been flown several times in the 2007-2011 time frame for the purpose of measuring CO2 mixing ratios in the lower atmosphere. The four most recent flight campaigns were on the NASA DC-8 research aircraft, in support of the NASA ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons mission formulation studies. This instrument operates in the 2.05-μm spectral region. The Integrated Path Differential Absorption (IPDA method is used to retrieve weighted CO2 column mixing ratios. We present key features of the CO2LAS signal processing, data analysis, and the calibration/validation methodology. Results from flights in various U.S. locations during the past three years include observed mid-day CO2 drawdown in the Midwest, also cases of point-source and regional plume detection that enable the calculation of emission rates.

  15. Airborne Laser Absorption Spectrometer Measurements of CO2 Column Mixing Ratios: Source and Sink Detection in the Atmospheric Environment

    Science.gov (United States)

    Menzies, Robert T.; Spiers, Gary D.; Jacob, Joseph C.

    2016-06-01

    The JPL airborne Laser Absorption Spectrometer instrument has been flown several times in the 2007-2011 time frame for the purpose of measuring CO2 mixing ratios in the lower atmosphere. The four most recent flight campaigns were on the NASA DC-8 research aircraft, in support of the NASA ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission formulation studies. This instrument operates in the 2.05-μm spectral region. The Integrated Path Differential Absorption (IPDA) method is used to retrieve weighted CO2 column mixing ratios. We present key features of the CO2LAS signal processing, data analysis, and the calibration/validation methodology. Results from flights in various U.S. locations during the past three years include observed mid-day CO2 drawdown in the Midwest, also cases of point-source and regional plume detection that enable the calculation of emission rates.

  16. Detection of Karenia mikimotoi by spectral absorption signatures

    DEFF Research Database (Denmark)

    Stæhr, P. A.; Cullen, J. J.

    2003-01-01

    properties of the algae, predictions based on the similarity index differed significantly depending on the acclimation of the algae. Furthermore, discriminating K. mikimotoi from natural phytoplankton assemblages indicated a significant influence of cell-size composition, through pigment packaging......, on the accuracy of the similarity index. Our results suggest that optical discrimination of phytoplankton species from spectral absorption signatures will improve significantly by applying the partial least-squares regression technique....

  17. Modeling absorption spectra for detection of the combustion products of jet engines by laser remote sensing.

    Science.gov (United States)

    Voitsekhovskaya, Olga K; Kashirskii, Danila E; Egorov, Oleg V; Shefer, Olga V

    2016-05-10

    The absorption spectra of exhaust gases (H2O, CO, CO2, NO, NO2, and SO2) and aerosol (soot and Al2O3) particles were modeled at different temperatures for the first time and suitable spectral ranges were determined for conducting laser remote sensing of the combustion products of jet engines. The calculations were conducted on the basis of experimental concentrations of the substances and the sizes of the aerosol particles. The temperature and geometric parameters of jet engine exhausts were also taken from the literature. The absorption spectra were obtained via the line-by-line method, making use of the spectral line parameters from the authors' own high-temperature databases (for NO2 and SO2 gases) and the HITEMP 2010 database, and taking into account atmospheric transmission. Finally, the theoretical absorption spectra of the exhaust gases were plotted at temperatures of 400, 700, and 1000 K, and the impact of aerosol particles on the total exhaust spectra was estimated in spectral ranges suitable for remote sensing applications.

  18. Highly Selective Hg (II Ion Detection Based on Linear Blue-Shift of the Maximum Absorption Wavelength of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Li Ping Wu

    2012-01-01

    Full Text Available A new method of detecting Hg (II ion with silver nanoparticles (AgNPs is developed in this contribution. When Hg (II ions were added into AgNPs solution, the solution displayed rapid color change and blue shift of the maximum absorption wavelength (Δλ, which was in proportion to the Hg (II ion concentration over the range of 2.0 × 10−7–6.0 × 10−6 mol/L, with detection limit (3σ of 6.6 × 10−9 mol/L. Under the same experimental conditions, other metal ions did not interfere. Thus, we propose a rapid, simple and highly selective method for detecting Hg (II ion.

  19. Changing of Bacteria Catalase Activity Under the Influence of Electro-Magnetic Radiation on a Frequency of Nitric Oxide Absorption and Radiation Molecular Spectrum

    Directory of Open Access Journals (Sweden)

    G.M. Shub

    2009-09-01

    Full Text Available The dynamics of catalase activity degree changing in Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa is described under the influence of electro-magnetic radiation on a frequency of nitric oxide absorption and radiation molecular spectrum. The panoramic spectrometric measuring complex, developed in Central Scientific Research Institute of measuring equipment Public corporation, Saratov, was used while carrying out the research. Electromagnetic vibrations of extremely high frequencies were stimulated in this complex imitating the structure of nitric oxide absorption and radiation molecular spectrum. The growth of activity of the mentioned enzyme of the strains under research was detected. The most significant changes were observed under 60-minutes exposure.

  20. Determination of Pb(Ⅱ) and Cu(Ⅱ) by Electrothermal Atomic Absorption Spectrometry after Preconcentration by a Schiff Base Adsorbed on Surfactant Coated Alumina

    Institute of Scientific and Technical Information of China (English)

    SABER TEHRANI Mohammad; RASTEGAR Faramarz; PARCHEHBAF Ayob; KHATAMIAN Masoomeh

    2006-01-01

    1,2-Bis(salicylidenamino)ethane loaded onto sodium dodecyl sulfate-coated alumina was used as a new chelating sorbent for the preconcentration of traces of Pb(Ⅱ) and Cu(Ⅱ) prior to atomic absorption spectrometric determination. The influence of pH, flow rates of sample and eluent solutions, and foreign ions on the recovery of Pb(Ⅱ)by electrothermal atomic absorption spectrometry (ETAAS). The data of limit of detection (3σ) for Pb(Ⅱ) and Cu(Ⅱ)posed method was successfully applied to determination of lead and copper in different water samples.

  1. Protein nitration in biological aging: proteomic and tandem mass spectrometric characterization of nitrated sites.

    Science.gov (United States)

    Kanski, Jaroslaw; Schöneich, Christian

    2005-01-01

    Proteomic techniques for the identification of 3-nitrotyrosine-containing proteins in various biological systems are described with emphasis on the direct mass spectrometric detection and sequencing of 3-nitrotyrosine-containing peptides. Strengths and weaknesses of various separation and mass spectrometric techniques are discussed. Some examples for the MS/MS analysis of nitrated peptides obtained from aging rat heart and skeletal muscle are provided, such as nitration of Tyr105 of the mitochondrial electron-transfer flavoprotein and Tyr14 of creatine kinase.

  2. A new detection technique of gas concentration with optical spectrum absorption at near-IR wavelength

    Institute of Scientific and Technical Information of China (English)

    井文才; 周之砚; 宋霄; 吴頔; 贾大功; 张红霞; 张以谟

    2009-01-01

    Wavelength modulation technique(WMT) and active intracavity technique(ACIT) are first introduced in this paper,which are used to realize the concentration detection of methane and acetylene respectively.When ACIT is combined with wavelength sweep technique(WST),the detection sensitivity of acetylene can be enhanced sharply.When ACIT is combined with WST and WMT,the detection sensitivity of acetylene can be enhanced further.

  3. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    Robert De Levie

    2009-09-01

    The spectrometric analysis of a mixture of two chemically and spectroscopically similar compounds is illustrated for the simultaneous spectrometric determination of caffeine and theobromine, the primary stimulants in coffee and tea, based on their ultraviolet absorbances. Their analysis indicates that such measurements may need an unexpectedly high precision to yield accurate answers, because of an artifact of inverse cancellation, in which a small noise or drift signal is misinterpreted in terms of a concentration difference. The computed sum of the concentrations is not affected.

  4. Development of gas fire detection system using tunable diode laser absorption spectroscopy

    Science.gov (United States)

    Jiang, Y. L.; Li, G.; Yang, T.; Wang, J. J.

    2017-01-01

    The conventional fire detection methods mainly produce an alarm through detecting the changes in smoke concentration, flame radiation, heat and other physical parameters in the environment, but are unable to provide an early warning of a fire emergency. We have designed a gas fire detection system with a high detection sensitivity and high selectivity using the tunable semiconductor diode laser as a light source and combining wavelength modulation and harmonic detection technology. This system can invert the second harmonic signal obtained to obtain the concentration of carbon monoxide gas (a fire characteristic gas) so as to provide an early warning of fire. We reduce the system offset noise and the background noise generated due to the laser interference by deducting the system background spectrum lines from the second harmonic signal. This can also eliminate the interference of other gas spectral lines to a large extent. We detected the concentration of the carbon monoxide gas generated in smoldering sandalwood fire and open beech wood fire with the homemade fire simulator, and tested the lowest detectable limit of system. The test results show that the lowest detectable limit can reach 5×10-6 the system can maintain stable operation for a long period of time and can automatically trigger a water mist fire extinguishing system, which can fully meet the needs of early fire warning.

  5. Detection Limit of Glucose Concentration with Near-Infrared Absorption and Scattering Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    LUO Yun-Han; HUANG Fu-Rong; LI Shi-Ping; CHEN Zhe

    2008-01-01

    @@ Theoretical analyses and Monte Carlo simulation are performed to investigate the detection limit of glucose concentration with near-infrared spectroscopy.The relation between detection limitation of glucose concentration and source-detector separation is derived.Monte Carlo simulation performed with a skin-layered model shows that the ratio of effective photons from the target layer could excess 50% by selecting proper source-detector separation,and that the detection limit of glucose concentration approaches to 0.28mM,which satisfies the requirement of food and drug administration for noninvasive glucose sensing.

  6. Breaking of symmetrical charge distribution in xanthylocyanine chromophores detecting by their absorption spectra

    Science.gov (United States)

    Vasyluk, S. V.; Viniychuk, O. O.; Poronik, Ye. M.; Kovtun, Yu. P.; Shandura, M. P.; Yashchuk, V. M.; Kachkovsky, O. D.

    2011-03-01

    A detailed experimental investigation and quantum-chemical analysis of symmetrical cyanines with xanthylium and its substituted derivatives and with different polymethine chain (containing 1 and 2 vinylene groups) have been performed with the goal of understanding the nature of the electronic transitions in molecules. It is established electronic transitions in carbocyanines are similar to that in the typical Brooker's cyanines. In contrast, the absorption spectra of dicarbocyanines demonstrate a strong solvent dependence and substantial band broadening represented by the growth of the short wavelength shoulder. Basing on the results of the quantum-chemical calculation and conception of the mobile solitonic-like charge waves, we have concluded that the dicarbocyanines exist in two charged forms in the ground state with symmetrical and unsymmetrical distributions of the charge density. These are the examples of the cationic cyanines with the shortest chain when the symmetry breaking occurs.

  7. Self-adaptive CH4 concentration detection system based on infrared spectrum absorption principle

    Institute of Scientific and Technical Information of China (English)

    YE Wei-lin; YU Xin; ZHENG Chuan-tao; ZHAO Cong-xin; CONG Meng-long; SONG Zhan-wei; WANG Yi-ding

    2011-01-01

    Considermg that the noises resulting from low modulation frequency are serious and cannot be totally eliminated by the classic filters, a novel infrared (IR) gas concentration detection system based on the least square fast transverse faltering (LS-FTF) self-adaptive modern filter structure is proposed. The principle, procedure and simulation on the LS-FTF algo-rithm are described. The system schematic diagram and key techniques are discussed. The procedures for the ARM7 processor, including LS-FTF and main program, are demonstrated. Comparisons between the experimental results of the detection system using the LS-FTF algorithm and those of the system without using this algorithm are performed. By using the LS-FTF algorithm, the maximum detection error is decreased from 14.3% to 5.4%, and also the detection stability increases as the variation range of the relative error becomes much smaller. The proposed LS-FTF self-adaptive denoising method can be of practical value for mid-lR gas detection, especially for weak signal detection.

  8. Detection of copper in water using on-line plasma-excited atomic absorption spectroscopy (AAS).

    Science.gov (United States)

    Porento, Mika; Sutinen, Veijo; Julku, Timo; Oikari, Risto

    2011-06-01

    A measurement method and apparatus was developed to measure continuously toxic metal compounds in industrial water samples. The method was demonstrated by using copper as a sample metal. Water was injected into the sample line and subsequently into a nitrogen plasma jet, in which the samples comprising the metal compound dissolved in water were decomposed. The transmitted monochromatic light was detected and the absorbance caused by copper atoms was measured. The absorbance and metal concentration were used to calculate sensitivity and detection limits for the studied metal. The sensitivity, limit of detection, and quantification for copper were 0.45 ± 0.02, 0.25 ± 0.01, and 0.85 ± 0.04 ppm, respectively.

  9. Optical detection of potassium chloride vapor using collinear photofragmentation and atomic absorption spectroscopy.

    Science.gov (United States)

    Sorvajärvi, Tapio; Saarela, Jaakko; Toivonen, Juha

    2012-10-01

    A sensitive and selective optical technique to detect potassium chloride (KCl) vapor is introduced. The technique is based on the photofragmentation of KCl molecules, using a pulsed UV laser, and optical probing of the temporarily increased amount of potassium atoms with a near-infrared laser. The two laser beams are aligned to go through the sample volume along the same optical path. The performance of the technique is demonstrated by detecting KCl concentrations from 25 ppb to 30 ppm in a temperature-controlled cell.

  10. Detection of Ocean Glint and Ozone Absorption Using LCROSS Earth Observations

    CERN Document Server

    Robinson, Tyler D; Meadows, Victoria S; Sparks, William; Bussey, D Ben J; Schwieterman, Edward W; Breiner, Jonathan

    2014-01-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 microns (R~500) and 1.17-2.48 microns (R~50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ~10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase dataset, ...

  11. Gamow-Teller decay and nuclear deformation: implementing of a new total absorption spectrometer, study of isotopes N {approx_equal} Z krypton and strontium; Decroissance Gamow-Teller et deformation nucleaire: mise en oeuvre d'un nouveau spectrometre a absorption totale, etude d'isotopes N {approx_equal} Z de krypton et strontium

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, E

    2002-12-01

    Nuclei with A {approx} 70 along the N=Z line are known to be the scene of phenomena closely related to the nuclear deformation and are of particular interest since theoretical mean field calculations predict that a large part of the Gamow-Teller resonance might be located below the ground state of the mother nucleus and then be accessible through {beta}-decay studies. These results have shown the effect of the shape of the ground state on the intensity of the Gamow-Teller strength. Thus, the experimental determination, through {delta}-decay, of the Gamow-Teller strength distribution and the comparison to the theoretical predictions allow to pin down the quadrupolar deformation parameter of the ground state of the parent nucleus. In order to study the neutron deficient isotopes of krypton (A=72,73,74,75) and strontium (A=76,77,78) and to establish the {beta}-strength on the full energy range, a new total absorption spectrometer (TAgS) has been built in the frame of an international collaboration and installed at the (SOLDE/CERN mass separator. For the data analysis, the response function R of the spectrometer has been calculated by means of Monte-Carlo simulations, based on the GEANT4 code, and of a statistical description of the level scheme in the daughter nucleus. The {beta}-feeding distribution has been obtained from experimental spectra through a method based on Bayes theorem and then converted into Gamow-Teller strength. The results coming from the {sup 74}Kr decay analysis allow to describe the ground state of such a nucleus as the coexistence of an oblate shape and of a prolate shape. In the case of {sup 76}Sr, the experimental Gamow-Teller strength distribution strongly indicates a prolate deformation. (author)

  12. QSO ABSORPTION SYSTEMS DETECTED IN Ne VIII: HIGH-METALLICITY CLOUDS WITH A LARGE EFFECTIVE CROSS SECTION

    Energy Technology Data Exchange (ETDEWEB)

    Meiring, J. D.; Tripp, T. M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Werk, J. K.; Prochaska, J. X. [University of California Observatories-Lick Observatory, UC Santa Cruz, CA 95064 (United States); Howk, J. C. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Jenkins, E. B. [Princeton University Observatory, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Lehner, N.; Sembach, K. R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2013-04-10

    Using high-resolution, high signal-to-noise ultraviolet spectra of the z{sub em} = 0.9754 quasar PG1148+549 obtained with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, we study the physical conditions and abundances of Ne VIII+O VI absorption line systems at z{sub abs} = 0.68381, 0.70152, 0.72478. In addition to Ne VIII and O VI, absorption lines from multiple ionization stages of oxygen (O II, O III, O IV) are detected and are well aligned with the more highly ionized species. We show that these absorbers are multiphase systems including hot gas (T Almost-Equal-To 10{sup 5.7} K) that produces Ne VIII and O VI, and the gas metallicity of the cool phase ranges from Z = 0.3 Z{sub Sun} to supersolar. The cool ( Almost-Equal-To 10{sup 4} K) phases have densities n{sub H} Almost-Equal-To 10{sup -4} cm{sup -3} and small sizes (<4 kpc); these cool clouds are likely to expand and dissipate, and the Ne VIII may be within a transition layer between the cool gas and a surrounding, much hotter medium. The Ne VIII redshift density, dN/dz{approx}7{sup +7}{sub -3}, requires a large number of these clouds for every L > 0.1 L* galaxy and a large effective absorption cross section ({approx}> 100 kpc), and indeed, we find a star-forming {approx}L {sup *} galaxy at the redshift of the z{sub abs} = 0.72478 system, at an impact parameter of 217 kpc. Multiphase absorbers like these Ne VIII systems are likely to be an important reservoir of baryons and metals in the circumgalactic media of galaxies.

  13. Targeted quantitative mass spectrometric immunoassay for human protein variants

    Directory of Open Access Journals (Sweden)

    Nedelkov Dobrin

    2011-04-01

    Full Text Available Abstract Background Post-translational modifications and genetic variations give rise to protein variants that significantly increase the complexity of the human proteome. Modified proteins also play an important role in biological processes. While sandwich immunoassays are routinely used to determine protein concentrations, they are oblivious to protein variants that may serve as biomarkers with better sensitivity and specificity than their wild-type proteins. Mass spectrometry, coupled to immunoaffinity separations, can provide an efficient mean for simultaneous detection and quantification of protein variants. Results Presented here is a mass spectrometric immunoassay method for targeted quantitative proteomics analysis of protein modifications. Cystatin C, a cysteine proteinase inhibitor and a potential marker for several pathological processes, was used as a target analyte. An internal reference standard was incorporated into the assay, serving as a normalization point for cystatin C quantification. The precision, linearity, and recovery characteristics of the assay were established. The new assay was also benchmarked against existing cystatin C ELISA. In application, the assay was utilized to determine the individual concentration of several cystatin C variants across a cohort of samples, demonstrating the ability to fully quantify individual forms of post-translationally modified proteins. Conclusions The mass spectrometric immunoassays can find use in quantifying specific protein modifications, either as a part of a specific protein biomarker discovery/rediscovery effort to delineate the role of these variants in the onset of the disease, progression, and response to therapy, or in a more systematic study to delineate and understand human protein diversity.

  14. Cavity enhanced absorption spectroscopy for N2O detection at 2.86μm using a continuous tunable color center laser

    Institute of Scientific and Technical Information of China (English)

    Shaocheng Li(李少成); Qingxu Yu(于清旭); Maarten van Herpen; Sacco te Lintel Hekkert; Frans J. M. Harren

    2003-01-01

    The cavity enhanced absorption technique is applied to N2O detection around 2.86 μm using a continuouswave color center laser. A high-finesse triangular ring cavity is used in this technology. Transmission through the cavity is obtained by jittering the cavity-length with a piezo on one of the cavity mirrors.A minimum detectable absorption coefficient of 2 × 10-6 cm-1 is achieved with a mirror reflectivity of 99.24%, corresponding to a N2O detection limit of 600 parts per billion.

  15. Selection of the optimal combination of water vapor absorption lines for detection of temperature in combustion zones of mixing supersonic gas flows by diode laser absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Mironenko V.R.

    2017-01-01

    Full Text Available Determination of a gas medium temperature by diode laser absorption spectrometry (DLAS is based on the measurement of integral intensities of the absorption lines of a test molecule (generally water vapor molecule. In case of local thermodynamic equilibrium temperature is inferred from the ratio of the integral intensities of two lines with different low energy levels. For the total gas pressure above 1 atm the absorption lines are broadened and one cannot find isolated well resolved water vapor absorption lines within relatively narrow spectral interval of fast diode laser (DL tuning range (about 3 cm−1. For diagnostics of a gas object in the case of high temperature and pressure DLAS technique can be realized with two diode lasers working in different spectral regions with strong absorption lines. In such situation the criteria of the optimal line selection differs significantly from the case of narrow lines. These criteria are discussed in our work. The software for selection the optimal spectral regions using the HITRAN-2012 and HITEMP data bases is developed. The program selects spectral regions of DL tuning, minimizing the error of temperature determination δТ/T, basing on the attainable experimental error of line intensity measurement δS. Two combinations of optimal spectral regions were selected – (1.392 & 1.343 μm and (1.392 & 1.339 μm. Different algorithms of experimental data processing are discussed.

  16. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded.

  17. Detecting Newcastle disease virus in combination of RT-PCR with red blood cell absorption

    Directory of Open Access Journals (Sweden)

    Liu Chengqian

    2011-05-01

    Full Text Available Abstract Reverse transcription-polymerase chain reaction (RT-PCR has limited sensitivity when treating complicated samples, such as feces, waste-water in farms, and nucleic acids, protein rich tissue samples, all the factors may interfere with the sensitivity of PCR test or generate false results. In this study, we developed a sensitive RT-PCR, combination of red blood cell adsorption, for detecting Newcastle disease virus (NDV. One pair of primers which was highly homologous to three NDV pathotypes was designed according to the consensus nucleocapsid protein (NP gene sequence. To eliminate the interfere of microbes and toxic substances, we concentrated and purified NDV from varied samples utilizing the ability of NDV binding red blood cells (RBCs. The RT-PCR coupled with red blood cell adsorption was much more sensitive in comparison with regular RT-PCR. The approach could also be used to detect other viruses with the property of hemagglutination, such as influenza viruses.

  18. Detection of gastrointestinal cancer by elastic scattering and absorption spectroscopies with the Los Alamos Optical Biopsy System

    Energy Technology Data Exchange (ETDEWEB)

    Mourant, J.R.; Boyer, J.; Johnson, T.M.; Lacey, J.; Bigio, I.J. [Los Alamos National Lab., NM (United States); Bohorfoush, A. [Wisconsin Medical School, Milwaukee, WI (United States). Dept. of Gastroenterology; Mellow, M. [Univ. of Oklahoma Medical School, Oklahoma City, OK (United States). Dept. of Gastroenterology

    1995-03-01

    The Los Alamos National Laboratory has continued the development of the Optical Biopsy System (OBS) for noninvasive, real-time in situ diagnosis of tissue pathologies. In proceedings of earlier SPIE conferences we reported on clinical measurements in the bladder, and we report here on recent results of clinical tests in the gastrointestinal tract. With the OBS, tissue pathologies are detected/diagnosed using spectral measurements of the elastic optical transport properties (scattering and absorption) of the tissue over a wide range of wavelengths. The use of elastic scattering as the key to optical tissue diagnostics in the OBS is based on the fact that many tissue pathologies, including a majority of cancer forms, exhibit significant architectural changes at the cellular and sub-cellular level. Since the cellular components that cause elastic scattering have dimensions typically on the order of visible to near-IR wavelengths, the elastic (Mie) scattering properties will be wavelength dependent. Thus, morphology and size changes can be expected to cause significant changes m an optical signature that is derived from the wavelength-dependence of elastic scattering. Additionally, the optical geometry of the OBS beneficially enhances its sensitivity for measuring absorption bands. The OBS employs a small fiber-optic probe that is amenable to use with any endoscope or catheter, or to direct surface examination, as well as interstitial needle insertion. Data acquistion/display time is <1 second.

  19. Detection of C2, CN, and NaID absorption in the AGB remnant of HD56126

    CERN Document Server

    Bakker, E J; Trams, N R; Van der Wolf, F L A; Bakker, Eric J; Trams, Norman R; Van der Wolf, Frank L A

    1995-01-01

    We present the detection of molecular absorption lines in the optical spectrum of the post-AGB star HD56126. The C2 Phillips A^{1}\\Pi_{u}-X^{1}\\Sigma^{+}_{g} (1,0), (2,0), and (3,0); Swan d^{3}\\Pi_{g}-a^{3}\\Pi_{u} (0,0) and (1,0); and CN Red system A^{2}\\Pi-X^{2}\\Sigma^{+} (1,0), (2,0), (3,0), and (4,0) bands have been identified. From the identification of the molecular bands we find an expansion velocity of 8.5+-0.6 kms independent of excitation condition or molecular specie. On the basis of the expansion velocity, rotational temperatures, and molecular column densities we argue that the line-forming region is the AGB remnant. This is in agreement with the expansion velocity derived from the CO lines. We find column densities of log N_C2=15.3+-0.3 cm-2 and log N_CN=15.5+-0.3 cm-2, and rotational temperatures of T_rot=242+-20 K and T_rot=24+-5 K respectively for C2 and CN. By studying molecular line absorption in optical spectra of post-AGB stars we have found a new tracer of the AGB remnant. From comparison...

  20. On the Putative Detection of z>0 X-ray Absorption Features in the Spectrum of Markarian 421

    CERN Document Server

    Rasmussen, A P; Den Herder, J W A; Kaastra, J; Kahn, S M; Paerels, F; Herder, Jan Willem den; Kaastra, Jelle; Kahn, Steven M.; Paerels, Frits; Rasmussen, Andrew P.; Vries, Cor de

    2006-01-01

    In a series of papers, Nicastro et al. have claimed the detection of z>0 O VII absorption features in the spectrum of Mrk 421 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We evaluate those claims in the context of a high quality spectrum of the same source obtained with the Reflection Grating Spectrometer (RGS) on XMM-Newton. The data comprise over 955~ksec of usable exposure time and more than 26000 counts per 50 milliAngstroms at 21.6 Angstroms. We concentrate on the spectrally clean region (21.3 < lambda < 22.5 Angstrom) where sharp features due to the astrophysically abundant O VII may reveal an intervening, warm-hot intergalactic medium (WHIM). In spite of the fact that the sensitivity of the RGS data is higher than that of the original LETGS data presented by Nicastro et al., we do not confirm detection of any of the intervening systems claimed to date. Rather, we detect only three unsurprising, astrophysically expected features down to the Log(N)~14.6 (3sigma) s...

  1. Spectrometric and Voltammetric Analysis of Urease – Nickel Nanoelectrode as an Electrochemical Sensor

    OpenAIRE

    Rene Kizek; Josef Zehnalek; Martin Adamek; Katerina Klosova; Ales Horna; Libuse Trnkova*; Michal Masarik; Dalibor Huska; Olga Krystofova; Vojtech Adam; Jan Hradecky; Jaromir Hubalek

    2007-01-01

    Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide and ammonia. This enzyme is substrate- specific, which means that the enzyme catalyzes the hydrolysis of urea only. This feature is a basic diagnostic criterion used in the determination of many bacteria species. Most of the methods utilized for detection of urease are based on analysis of its enzyme activity - the hydrolysis of urea. The aim of this work was to detect urease indirectly by spectrometric method and dire...

  2. On the Putative Detection of z > 0 X-Ray Absorption Features in the Spectrum of Mrk 421

    Science.gov (United States)

    Rasmussen, Andrew P.; Kahn, Steven M.; Paerels, Frits; Herder, Jan Willem den; Kaastra, Jelle; de Vries, Cor

    2007-02-01

    In a series of papers, Nicastro et al. have reported the detection of z>0 O VII absorption features in the spectrum of Mrk 421 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We evaluate this result in the context of a high-quality spectrum of the same source obtained with the Reflection Grating Spectrometer (RGS) on XMM-Newton. The data comprise over 955 ks of usable exposure time and more than 2.6×104 counts per 50 mÅ at 21.6 Å. We concentrate on the spectrally clean region (21.3 <λ<22.5 ), where sharp features due to the astrophysically abundant O VII may reveal an intervening, warm-hot intergalactic medium (WHIM). We do not confirm detection of any of the intervening systems claimed to date. Rather, we detect only three unsurprising, astrophysically expected features down to the log(Ni)~14.6 (3 σ) sensitivity level. Each of the two purported WHIM features is rejected with a statistical confidence that exceeds that reported for its initial detection. While we cannot rule out the existence of fainter, WHIM related features in these spectra, we suggest that previous discovery claims were premature. A more recent paper by Williams et al. claims to have demonstrated that the RGS data we analyze here do not have the resolution or statistical quality required to confirm or deny the LETGS detections. We show that our analysis resolves the issues encountered by Williams et al. and recovers the full resolution and statistical quality of the RGS data. We highlight the differences between our analysis and those published by Williams et al. as this may explain our disparate conclusions.

  3. A novel microwave absorption and dielectric spectrum detection technology in photoelectron dynamic study for solar cells

    Institute of Scientific and Technical Information of China (English)

    LI Xiaowei; SUN Shuxu; LAI Weidong; ZHANG Rongxiang; DAI Xiuhong; JIANG Xiaoli

    2006-01-01

    The photoelectron property is directly related to the light-energy conversion efficiency of solar cells. In this paper, the photoelectron dynamic of semiconductor was analyzed. The diffusion of electrons has influence on the dielectric function of the solar cell material. And the amplitude variance of the imaginary andreal part of the dielectric function is in direct proportion to the dynamic process of free and shallow-trapped electrons. Based on the untouched detection technique, the method is present to detect the amplitude change of the microwave signal which is passing through the material whose dielectric function changes after exposure. A35GHz oscillator was used as a microwave source. The absorptionand dispersion microwave signals, which contain the dynamic information of free and shallow-trapped electron signal, are split respectively with phase-sensitive instrument. The photoelectron character of n-type Si(100) thin film was investigated by the novel equipment, and the lifetime of different kinds of electronswith the resolution of 1 ns was obtained. The equipment can be directly used inthe study of the optoelectronic conversion mechanism of solar cells.

  4. The analysis of comet mass spectrometric data

    Science.gov (United States)

    Balm, S. P.; Hare, J. P.; Kroto, H. W.

    1991-04-01

    The mass spectra from the Giotto PICCA experiment have been studied using computer simulations based on tabulated mass spectrometric data. It is shown that random mixtures of organic compounds give rise to mass spectra with peaks at about 45, 60, 75, and 90 amu; i.e., separated by about 15 amu. In particular it is shown that the products of Urey-Miller type experiments give mass spectra which can match the observed Giotto data closely. The analysis indicates that the material consists mainly of C/H/O/N (i.e., it is organic), but that the assignment to any well defined organic material is less certain. It is not clear that mass spectrometric studies of complex mixtures have the prospect of yielding this type of information without some form of preseparation.

  5. Spectrometric Characterization of Active Geosynchronous Satellites

    Science.gov (United States)

    Bedard, D.; Monin, D.; Scott, R.; Wade, G.

    2012-09-01

    Spectrometric characterization of artificial space objects for the purposes of Space Situational Awareness (SSA) has demonstrated great potential since this technique was first reported at this conference over a decade ago. Yet, much scientific work remains to be done before this tool can be used reliably in an operational context. For example, a detailed study of the impacts of a dynamic illumination-object-sensor geometry during individual spectrometric observations has yet to be described. A thorough understanding of this last problem is considered critical if reflectance spectroscopy will be used to characterize active low Earth orbiting spacecraft, in which the Sun-object-sensor geometry varies considerably over the course of a few seconds, or to study space debris that have uncontrolled and varying attitude. It is with the above questions in mind that two observation campaigns were conducted. The first consisted in using small-aperture telescopes to obtain multi-color photometric light curves of active geosynchronous satellites over a wide range of phase angles. The second observation campaign was conducted at the Dominion Astrophysical Observatory (DAO) using the 1.8-metre Plaskett telescope and its Cassegrain spectrograph. The objective of this experiment was to gather time-resolved spectrometric measurements of active geosynchronous satellites as a function of phase angle. This class of satellites was selected because their attitude is controlled and can be estimated to a high level of confidence. This paper presents the two observation campaigns and provides a summary of the key results of this experiment.

  6. A Method for Detecting the Deterioration in the Shock Absorption Capability of Mouthguards.

    Science.gov (United States)

    Tanaka, Y; Miyanaga, H; Maeda, Y; Abe, M; Miwa, S

    2015-07-01

    Objective methods for mechanical assessment of mouthguards used for a prolonged period of time are currently unavailable. The aim of this experimental study was to establish a quantitative method for assessing the preventive effect of mouthguards. 10 participants volunteered for this study. Impact loads were simulated by dropping a 250-g steel rod from a height of 100 mm onto upper front teeth of 10 custom ethylene vinyl acetate mouthguards fixed to a steel receiving rod. The mean output from load cells equilaterally placed between plates at the base of the apparatus was measured as the impact pressure (N). Its attenuation ratio (%) was calculated as the ratio of the difference in impact pressures without and with a mouthguard to impact pressure without a mouthguard. Impact pressure with mouthguard was approximately 60% of that without mouthguard in all cases. Intraclass correlations showed excellent intra-rater and inter-rater reliability for attenuation ratio (0.98 and 0.94, respectively). Bland-Altman plots indicated lack of systematic bias. The results suggest that attenuation ratio of impact pressure calculated by the proposed method is a valid criterion for assessing the preventive effect of mouthguards. The method may enable early detection of mouthguard deterioration and their timely replacement.

  7. Extraction, chromatographic and mass spectrometric methods for lipid analysis.

    Science.gov (United States)

    Pati, Sumitra; Nie, Ben; Arnold, Robert D; Cummings, Brian S

    2016-05-01

    Lipids make up a diverse subset of biomolecules that are responsible for mediating a variety of structural and functional properties as well as modulating cellular functions such as trafficking, regulation of membrane proteins and subcellular compartmentalization. In particular, phospholipids are the main constituents of biological membranes and play major roles in cellular processes like transmembrane signaling and structural dynamics. The chemical and structural variety of lipids makes analysis using a single experimental approach quite challenging. Research in the field relies on the use of multiple techniques to detect and quantify components of cellular lipidomes as well as determine structural features and cellular organization. Understanding these features can allow researchers to elucidate the biochemical mechanisms by which lipid-lipid and/or lipid-protein interactions take place within the conditions of study. Herein, we provide an overview of essential methods for the examination of lipids, including extraction methods, chromatographic techniques and approaches for mass spectrometric analysis.

  8. Photothermal deflection spectroscopy for the study of thin films and optical coatings: measurements of absorption losses and detection of photoinduced changes

    Science.gov (United States)

    Commandre, Mireille; Roche, Pierre J.; Albrand, Gerard; Pelletier, Emile P.

    1990-08-01

    Photothermal deflection has been used to map the absorption characteristics of thin film optical coatings. Our experimental set-up can give low level absorption coefficient down to 1 ppm, with a spatial resolution limited by the excitating laser beam diameter (100 tim). On single layer films, we can calculate extinction coefficient of the deposited material with a detectivity of a few i07. We present a study of absorption losses in single layer titania films and in TiOWSiO2 Fabry-Perot filters prepared in our laboratory by electron beam evaporation, ion assisted deposition and ion plating. Local variations of absorption on the sample surface can be very large especially in lowly absorbing samples; high absorption sites may be related to local defects responsible for laser damage. Furthermore, we show that some titania films can present photoinduced instabilities. Photothermal deflection spectroscopy is a good way to study absorption evolution under illumination. In Ti02/Si02 Fabry-Perot filters, we have observed that these absorption changes are associated with important drifts of transmission curves. So these instabilities can be explained by a change of the value of the complex index Ii = n - ik. Results lead to the conclusion that stability under illumination is strongly correlated to the deposition technique and also to the deposition conditions: unstable samples are mostly prepared by electron beam evaporation.

  9. HST/COS Spectra of DF Tau and V4046 SGR: First Detection of Molecular Hydrogen Absorption Against the Ly$\\alpha$ Emission Line

    CERN Document Server

    Yang, Hao; France, Kevin

    2011-01-01

    We report the first detection of molecular hydrogen (H$_{2}$) absorption in the Lyman-$\\alpha$ emission line profiles of two classical T Tauri stars (CTTSs), DF Tau and V4046 Sgr, observed by \\emph{HST}/COS. This absorption is the energy source for many of the Lyman-band H$_{2}$ fluorescent lines commonly seen in the far-ultraviolet spectra of CTTSs. We find that the absorbed energy in the H$_{2}$ pumping transitions from a portion of the Lyman-$\\alpha$ line significantly differ from the amount of energy in the resulting fluorescent emission. By assuming additional absorption in the H I Lyman-$\\alpha$ profile along our light of sight, we can correct the H$_{2}$ absorption/emission ratios so that they are close to unity. The required H I absorption for DF Tau is at a velocity close to the radial velocity of the star, consistent with H I absorption in the edge-on disk and interstellar medium. For V4046 Sgr, a nearly face-on system, the required absorption is between +100 km/s and +290 km/s, most likely resultin...

  10. Multi-Epoch Detections of Water Ice Absorption in Edge-on Disks around Herbig Ae Stars: PDS 144N and PDS 453

    CERN Document Server

    Terada, Hiroshi

    2016-01-01

    We report the multi-epoch detections of the water ice in 2.8-4.2 micron spectra of two Herbig Ae stars, PDS 144N (A2 IVe) and PDS 453 (F2 Ve), which have an edge-on circumstellar disk. The detected water ice absorption is found to originate from their protoplanetary disks. The spectra show a relatively shallow absorption of water ice around 3.1 micron for both objects. The optical depths of the water ice absorption are ~0.1 and ~0.2 for PDS 144N and PDS 453, respectively. Compared to the water ice previously detected in low-mass young stellar objects with an edge-on disk with a similar inclination angle, these optical depths are significantly lower. It suggests that stronger UV radiation from the central stars effectively decreases the water ice abundance around the Herbig Ae stars through photodesorption. The water ice absorption in PDS 453 shows a possible variation of the feature among the six observing epochs. This variation could be due to a change of absorption materials passing through our line-of-sigh...

  11. Infrared absorption of gaseous CH{sub 2}BrOO detected with a step-scan Fourier-transform absorption spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yu-Hsuan [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Lee, Yuan-Pern, E-mail: yplee@mail.nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China)

    2014-10-28

    CH{sub 2}BrOO radicals were produced upon irradiation, with an excimer laser at 248 nm, of a flowing mixture of CH{sub 2}Br{sub 2} and O{sub 2}. A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to record temporally resolved infrared (IR) absorption spectra of reaction intermediates. Transient absorption with origins at 1276.1, 1088.3, 961.0, and 884.9 cm{sup −1} are assigned to ν{sub 4} (CH{sub 2}-wagging), ν{sub 6} (O–O stretching), ν{sub 7} (CH{sub 2}-rocking mixed with C–O stretching), and ν{sub 8} (C–O stretching mixed with CH{sub 2}-rocking) modes of syn-CH{sub 2}BrOO, respectively. The assignments were made according to the expected photochemistry and a comparison of observed vibrational wavenumbers, relative IR intensities, and rotational contours with those predicted with the B3LYP/aug-cc-pVTZ method. The rotational contours of ν{sub 7} and ν{sub 8} indicate that hot bands involving the torsional (ν{sub 12}) mode are also present, with transitions 7{sub 0}{sup 1}12{sub v}{sup v} and 8{sub 0}{sup 1}12{sub v}{sup v}, v = 1–10. The most intense band (ν{sub 4}) of anti-CH{sub 2}BrOO near 1277 cm{sup −1} might have a small contribution to the observed spectra. Our work provides information for directly probing gaseous CH{sub 2}BrOO with IR spectroscopy, in either the atmosphere or laboratory experiments.

  12. Development and validation of highly selective screening and confirmatory methods for the qualitative forensic analysis of organic explosive compounds with high performance liquid chromatography coupled with (photodiode array and) LTQ ion trap/Orbitrap mass spectrometric detections (HPLC-(PDA)-LTQOrbitrap).

    Science.gov (United States)

    Xu, Xiaoma; Koeberg, Mattijs; Kuijpers, Chris-Jan; Kok, Eric

    2014-01-01

    An LTQ-Orbitrap FTMS is a new (hybrid) mass spectrometric (MS) analyzer. It allows for the acquisition of full scan MS(n) (n-stage fragmentations, n=1-n) spectra with the linear ion trap detector (LTQ) at high speed and/or with the Fourier Transform-detector (Orbitrap) with ultra high mass resolution (>60,000 at m/zphoto diode array (PDA) detection. Two methods for the forensic screening and confirmation of all common trace explosives in post-blast residues have been developed on this instrument using atmospheric pressure chemical ionization (APCI). In one run, the nitrogen-containing explosives are analyzed with the combination of "LC-(PDA)-APCI(-)-LTQ MS(2)/Orbitrap FTMS" (Method 1). In another run, peroxide explosives are analyzed with "LC-APCI(+)-LTQ MS(2)/Orbitrap FTMS" (Method 2). The performance of both methods has been validated according to procedures defined in the EU COMMISSION DECISION implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results (DC 2002/657/EC) and other standards (NEN 17025 and NEN 7777). The methods are highly selective due to the simultaneous utilization of the Orbitrap FTMS and LTQ MS(2), both of which are highly selective detectors Tested explosive compounds can be detected in the molecular ion form by the Orbitrap analyzer with minimal mass interference in different matrices when using an extremely narrow mass tolerance detection window (≤2ppm). The identification of a detected compound follows an identification point system. Experimental results show that almost all explosive compounds meet the confirmation criteria (minimum 4 points) required for the positive identification by the DC 2002/657/EC.

  13. Gaia and its spectrometric challenge

    Energy Technology Data Exchange (ETDEWEB)

    Thevenin, F [Universite de Nice, Laboratoire Cassiopee, CNRS, OCA, BP 4229, 06304 Nice Cedex (France)], E-mail: frederic.thevenin@oca.eu

    2008-12-15

    The Gaia program was kicked off at the beginning of 2006 and is now reaching a phase of construction and integration for a launch at the end of 2011, to reach the L2 point several months later. Apart from that industrial activity, the European astronomical community is actively preparing the data treatment and in particular how to extract the astrophysical parameter outputs from the use of the spectrographs on board the satellite. This work consists of the realization of algorithms to extract fundamental parameters of the detected source points with the help of an extensive grid of synthetic spectral libraries. The number of these estimated fundamental parameters and their accuracy depend on the ability of the algorithms to treat the spectra and to compare them with the computed ones, and also on the quality of the synthetic spectra themselves. Then, on the one hand a huge effort is underway to produce these extensive grids of one-dimensional (1D) local thermodynamic equilibrium (LTE) spectra of stars, galaxies, quasi-stellar objects and asteroids, and on the other hand, new physics is tested in the atmosphere model of stars to improve the theoretical libraries. An example of the questions we need to answer is: do we need 3D non-local thermodynamic equilibrium (NLTE) modelling? If yes, the libraries will then be improved by adding corrections checked on dedicated standard stars. Shall we be able to implement this new physics in a reasonable time? This is another challenge.

  14. Gaia and its spectrometric challenge

    Science.gov (United States)

    Thévenin, F.

    2008-12-01

    The Gaia program was kicked off at the beginning of 2006 and is now reaching a phase of construction and integration for a launch at the end of 2011, to reach the L2 point several months later. Apart from that industrial activity, the European astronomical community is actively preparing the data treatment and in particular how to extract the astrophysical parameter outputs from the use of the spectrographs on board the satellite. This work consists of the realization of algorithms to extract fundamental parameters of the detected source points with the help of an extensive grid of synthetic spectral libraries. The number of these estimated fundamental parameters and their accuracy depend on the ability of the algorithms to treat the spectra and to compare them with the computed ones, and also on the quality of the synthetic spectra themselves. Then, on the one hand a huge effort is underway to produce these extensive grids of one-dimensional (1D) local thermodynamic equilibrium (LTE) spectra of stars, galaxies, quasi-stellar objects and asteroids, and on the other hand, new physics is tested in the atmosphere model of stars to improve the theoretical libraries. An example of the questions we need to answer is: do we need 3D non-local thermodynamic equilibrium (NLTE) modelling? If yes, the libraries will then be improved by adding corrections checked on dedicated standard stars. Shall we be able to implement this new physics in a reasonable time? This is another challenge.

  15. Column solid phase extraction and flame atomic absorption spectrometric determination of manganese(II) and iron(III) ions in water, food and biological samples using 3-(1-methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid on synthesized graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Pourjavid, Mohammad Reza, E-mail: pourjavid@gmail.com [NFCRS, Nuclear Science and Technology Research Institute, P.O. Box 11365-8486, Tehran (Iran, Islamic Republic of); Sehat, Ali Akbari [Department of Analytical Chemistry, Faculty of Chemistry, University College of Science, University of Tehran, P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Arabieh, Masoud; Yousefi, Seyed Reza; Hosseini, Majid Haji; Rezaee, Mohammad [NFCRS, Nuclear Science and Technology Research Institute, P.O. Box 11365-8486, Tehran (Iran, Islamic Republic of)

    2014-02-01

    A modified, selective, highly sensitive and accurate procedure for the determination of trace amounts of manganese and iron ions is established in the presented work. 3-(1-Methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid (MPPC) and graphene oxide (GO) were used in a glass column as chelating reagent and as adsorbent respectively prior to their determination by flame atomic absorption spectrometry. The adsorption mechanism of titled metals complexes on GO was investigated by using computational chemistry approach based on PM6 semi-empirical potential energy surface (PES). The effect of some parameters including pH, flow rate and volume of sample and type, volume and concentration of eluent, as well as the adsorption capacity of matrix ions on the recovery of Mn(II) and Fe(III) was investigated. The limit of detection was 145 and 162 ng L{sup −1} for Mn(II) and Fe(III), respectively. Calibration was linear over the range of 0.31–355 μg L{sup −1} for Mn(II) and 0.34–380 μg L{sup −1} for Fe(III) ions. The method was successfully applied for the determination of understudied ions in water, food and biological samples. - Highlights: • We use synthesized graphene oxide as adsorbent for SPE of Mn(II) and Fe(III) ions. • Adsorption mechanism was investigated by PM6 semi-empirical potential energy surface. • Detection limits were 145 and 162 ng L{sup −1} for Mn and Fe, respectively. • The preconcentration factor was 325 and sample flow rate is 8 mL min{sup −1}. • It was successfully applied to the determination of Mn and Fe ions in real samples.

  16. Mass spectrometric determination of early and advanced glycation in biology.

    Science.gov (United States)

    Rabbani, Naila; Ashour, Amal; Thornalley, Paul J

    2016-08-01

    Protein glycation in biological systems occurs predominantly on lysine, arginine and N-terminal residues of proteins. Major quantitative glycation adducts are found at mean extents of modification of 1-5 mol percent of proteins. These are glucose-derived fructosamine on lysine and N-terminal residues of proteins, methylglyoxal-derived hydroimidazolone on arginine residues and N(ε)-carboxymethyl-lysine residues mainly formed by the oxidative degradation of fructosamine. Total glycation adducts of different types are quantified by stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Metabolism of glycated proteins is followed by LC-MS/MS of glycation free adducts as minor components of the amino acid metabolome. Glycated proteins and sites of modification within them - amino acid residues modified by the glycating agent moiety - are identified and quantified by label-free and stable isotope labelling with amino acids in cell culture (SILAC) high resolution mass spectrometry. Sites of glycation by glucose and methylglyoxal in selected proteins are listed. Key issues in applying proteomics techniques to analysis of glycated proteins are: (i) avoiding compromise of analysis by formation, loss and relocation of glycation adducts in pre-analytic processing; (ii) specificity of immunoaffinity enrichment procedures, (iii) maximizing protein sequence coverage in mass spectrometric analysis for detection of glycation sites, and (iv) development of bioinformatics tools for prediction of protein glycation sites. Protein glycation studies have important applications in biology, ageing and translational medicine - particularly on studies of obesity, diabetes, cardiovascular disease, renal failure, neurological disorders and cancer. Mass spectrometric analysis of glycated proteins has yet to find widespread use clinically. Future use in health screening, disease diagnosis and therapeutic monitoring, and

  17. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    DEFF Research Database (Denmark)

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel

    2005-01-01

    . The samples are adjusted to pH 5.0 on-line in the system for optimum operation. The target ions are adsorbed by chelation on the surface of the beads, contained in a 20 mul microcolumn within the LOV, and following elution by 50 mul 2M nitric acid, the eluate is, as sandwiched by air segments, introduced...

  18. Development of a 2-micron Pulsed Differential Absorption Lidar for Atmospheric CO2 Concentration Measurement by Direct Detection Technique

    Science.gov (United States)

    Yu, J.; Singh, U. N.; Petros, M.; Bai, Y.

    2011-12-01

    Researchers at NASA Langley Research Center are developing a 2-micron Pulsed Differential Absorption Lidar instrument for ground and airborne measurements via direct detection method. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capbility by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement. A key component of the CO2 DIAL system, transceiver, is an existing, airborne ready, robust hardware which can provide 250mJ at 10Hz with double pulse format specifically designed for DIAL instrument. The exact wavelengths of the transceiver are controlled by well defined CW seed laser source to provide the required injection source for generating on-and-off line wavelength pulses sequentially. The compact, rugged, highly reliable transceiver is based on the unique Ho:Tm:YLF high-energy 2-micron pulsed laser technology. All the optical mounts are custom designed and have space heritage. They are designed to be adjustable and lockable and hardened to withstand vibrations that can occur in airborne operation. For the direct detection lidar application, a large primary mirror size is preferred. A 14 inch diameter telescope will be developed for this program. The CO2 DIAL/IPDA system requires many electronic functions to operate. These include diode, RF, seed laser, and PZT drivers; injection seeding detection and control; detector power supplies; and analog inputs to sample various sensors. Under NASA Laser Risk Reduction Program (LRRP), a control unit Compact Laser Electronics (CLE), is developed for the controlling the coherent wind lidar transceiver. Significant modifications and additions are needed to update it for CO2 lidar controls. The data acquisition system was built for ground CO2 measurement demonstration. The software will be updated for

  19. Bolometric detection of magnetoplasma resonances in microwave absorption by two-dimensional electron systems based on doping layer conductivity measurements in GaAs/AlGaAs heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Dorozhkin, S. I., E-mail: dorozh@issp.ac.ru; Sychev, D. V.; Kapustin, A. A. [Institute of Solid State Physics RAS, 142432 Chernogolovka, Moscow district (Russian Federation)

    2014-11-28

    We have implemented a new bolometric method to detect resonances in magneto-absorption of microwave radiation by two-dimensional electron systems (2DES) in selectively doped GaAs/AlGaAs heterostructures. Radiation is absorbed by the 2DES and the thermally activated conductivity of the doping layer supplying electrons to the 2DES serves as a thermometer. The resonant absorption brought about by excitation of the confined magnetoplasma modes appears as peaks in the magnetic field dependence of the low-frequency impedance measured between the Schottky gate and 2DES.

  20. Time-resolved detection of temperature, concentration, and pressure in a shock tube by intracavity absorption spectroscopy

    Science.gov (United States)

    Fjodorow, Peter; Fikri, Mustapha; Schulz, Christof; Hellmig, Ortwin; Baev, Valery M.

    2016-06-01

    In this paper, we demonstrate the first application of intracavity absorption spectroscopy (ICAS) for monitoring species concentration, total pressure, and temperature in shock-tube experiments. ICAS with a broadband Er3+-doped fiber laser is applied to time-resolved measurements of absorption spectra of shock-heated C2H2. The measurements are performed in a spectral range between 6512 and 6542 cm-1, including many absorption lines of C2H2, with a time resolution of 100 µs and an effective absorption path length of 15 m. Up to 18-times increase of the total pressure and a temperature rise of up to 1200 K have been monitored. Due to the ability of simultaneously recording many absorption lines in a broad spectral range, the presented technique can also be applied to multi-component analysis of transient single-shot processes in reactive gas mixtures in shock tubes, pulse detonation engines, or explosions.

  1. Evidence for ultra-fast outflows in radio-quiet AGNs: I - detection and statistical incidence of Fe K-shell absorption lines

    CERN Document Server

    Tombesi, F; Reeves, J N; Palumbo, G G C; Yaqoob, T; Braito, V; Dadina, M

    2010-01-01

    We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies E>7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3x10^-8, and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability <10^-7. We identify the lines as Fe XXV and Fe XXVI K-shell resonant absorption. They are systematically blue-shifted, with a velocity distribution ranging from zero up to 0.3c, with a peak and mean value at 0.1c. We detect variability of the lines on both EWs and blue-shifted velocities among different observations even on time-scales as short as a few days, possibly suggesting somewhat compact absorbers. Moreover, we find no significant correlation between the cosmological red-sh...

  2. Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane—Breath Biomarkers of Serious Diseases

    Directory of Open Access Journals (Sweden)

    Jacek Wojtas

    2015-06-01

    Full Text Available The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (<3 s were achieved. Absorption lines of reference samples of the selected volatile biomarkers were probed using a distributed feedback quantum cascade laser and a tunable laser system consisting of an optical parametric oscillator and difference frequency generator. Setup using the first source provided a detection limit of 30 ppb for nitric oxide and 250 ppb for carbonyl sulphide. During experiments employing a second laser, detection limits of 0.9 ppb and 0.3 ppb were obtained for carbonyl sulphide and ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases.

  3. Shock tube study on the thermal decomposition of fluoroethane using infrared laser absorption detection of hydrogen fluoride.

    Science.gov (United States)

    Matsugi, Akira; Shiina, Hiroumi

    2014-08-28

    Motivated by recent shock tube studies on the thermal unimolecular decomposition of fluoroethanes, in which unusual trends have been reported for collisional energy-transfer parameters, the rate constants for the thermal decomposition of fluoroethane were investigated using a shock tube/laser absorption spectroscopy technique. The rate constants were measured behind reflected shock waves by monitoring the formation of HF by IR absorption at the R(1) transition in the fundamental vibrational band near 2476 nm using a distributed-feedback diode laser. The peak absorption cross sections of this absorption line have also been determined and parametrized using the Rautian-Sobel'man line shape function. The rate constant measurements covered a wide temperature range of 1018-1710 K at pressures from 100 to 290 kPa, and the derived rate constants were successfully reproduced by the master equation calculation with an average downward energy transfer, ⟨ΔEdown⟩, of 400 cm(-1).

  4. New Perspective on Galaxy Outflows From the First Detection of Both Intrinsic and Traverse Metal-Line Absorption

    CERN Document Server

    Kacprzak, Glenn G; Bouché, Nicolas; Churchill, Christopher W; Cooke, Jeff; LeReun, Audrey; Schroetter, Ilane; Ho, Stephanie H; Klimek, Elizabeth

    2014-01-01

    We present the first observation of a galaxy (z=0.2) that exhibits metal-line absorption back-illuminated by the galaxy ("down-the-barrel") and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by MgII, are blueshifted relative to the galaxy systemic velocity. The quasar sight-line, which resides almost directly along the projected minor axis of the galaxy, probes MgI and MgII absorption obtained from Keck/LRIS and Lya, SiII and SiIII absorption obtained from HST/COS. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between $V_{dtb}=45-255$ km/s. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities $V_{outflow}=40-80$ km/s to reproduce the transverse MgII absorption kinematics, which is consistent with the range of $V_...

  5. Evaluation of mass spectrometric techniques for characterization of engineered proteins

    DEFF Research Database (Denmark)

    Roepstorff, P; Schram, K H; Andersen, Jens S.;

    1995-01-01

    Mass spectrometric characterization of engineered proteins has been examined using bovine recombinant Acyl-CoA-Binding Protein (rACBP), [15N]-labeled rACBP, and a number of sequence variants of ACBP produced by site-directed mutagenesis. The mass spectrometric techniques include ESIMS and MALDIMS...... was obtained by LC-ESIMS and by direct mixture analysis by MALDIMS. The latter technique was favorable in terms of sensitivity and speed. A general strategy for mass spectrometric characterization of engineered proteins is suggested....

  6. Use of a hydrolytic procedure and spectrometric methods in the structure elucidation of a thiocarbonyl analogue of sildenafil detected as an adulterant in an over-the-counter herbal aphrodisiac.

    Science.gov (United States)

    Reepmeyer, John C; D'Avignon, D André

    2009-01-01

    A sildenafil-related compound was detected in an herbal dietary supplement marketed as an aphrodisiac. The compound was identified as an analogue of sildenafil in which the carbonyl group in the pyrimidine ring of sildenafil was substituted with a thiocarbonyl group, and the methyl group on the piperazine ring was substituted with a hydroxyethyl group. Based on this structure, the compound was named thiohydroxyhomosildenafil. The structure of the compound was established using HPLCIMS, UV spectrometry, electrospray ionization-MS/MS, NMR spectrometry, and a hydrolytic process. One key product of hydrolysis was 1-(2-hydroxyethyl)-piperazine; the identification of this product defined the amine portion of the compound. Another key product of hydrolysis was hydroxyhomosildenafil, generated by hydrolysis of the thiocarbonyl group to a carbonyl group (C = S --> C = O). Hydroxyhomosildenafil was detected as a minor component in the dietary supplement.

  7. 载人航天器密封舱微量有害气体质谱检测方法%Mass spectrometric detection of harmful trace gases in manned spacecraft capsule

    Institute of Scientific and Technical Information of China (English)

    陈联; 邱家稳; 王丽红; 张晓曦

    2011-01-01

    Detection of multi -component harmful trace gases in manned spacecraft capsule by miniature vacuum mass spectrometer was introduced. Online monitoring of a variety of harmful trace gases in the capsule was realized through detecting the gas concentration. Experimental data of relative sensitivity of some gases such as toluene, dimethylbenzene, dichloromethane, methane and acetone were given and the experiment also verified that the minimum detectable concentration of before -mentioned gases can reach lppm. The results indicated that monitoring of harmful trace gas concentration by miniature vacuum mass spectrometer in manned spacecraft capsule is feasible.%介绍了采用小型真空质谱计进行载人航天器密封舱内多组分微量有害气体的检测方法.通过测量微量气体浓度,实现密封舱内多种微量有害气体在线监测.给出了甲苯、二甲苯、二氯甲烷、甲烷、丙酮等5种气体的相对灵敏度试验数据,验证了现有小型真空质谱计最小可检浓度可以达到1ppm要求.研究结果表明,采用小型真空质谱计进行舱内微量有害气体浓度监测是可行的.

  8. Liquid chromatography-mass spectrometric and liquid chromatography-tandem mass spectrometric determination of hallucinogenic indoles psilocin and psilocybin in "magic mushroom" samples.

    Science.gov (United States)

    Kamata, Tooru; Nishikawa, Mayumi; Katagi, Munehiro; Tsuchihashi, Hitoshi

    2005-03-01

    Accurate and sensitive analytical methods for psilocin (PC) and psilocybin (PB), tryptamine-type hallucinogens contained in "magic mushrooms," were investigated using liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The chromatographic separation on an ODS column and mass spectral information gave complete discrimination between PC and PB without derivatization. The mass spectrometric detection had a high sensitivity, and the tandem mass spectrometric detection provided more specificity and accuracy, as well as high sensitivity. The detection limits ranged from 1 to 25 pg by LC-MS in the selected ion monitoring mode, and the intra- and inter-day coefficients of variation were estimated to be 4.21-5.93% by LC-MS-MS in the selected reaction monitoring mode. By applying the present LC-MS-MS technique to four real samples, the contents of PC and PB were found to vary over a wide range (0.60-1.4 and 0.18-3.8 mg/g dry wt. for PC and PB, respectively) between samples.

  9. Chandra View of the Warm-Hot IGM toward 1ES 1553+113: Absorption Line Detections and Identifications (Paper I)

    CERN Document Server

    Nicastro, F; Krongold, Y; Mathur, S; Gupta, A; Danforth, C; Barcons, X; Borgani, S; Branchini, E; Cen, R; Davé, R; Kaastra, J; Paerels, F; Piro, L; Shull, J M; Takei, Y; Zappacosta, L

    2012-01-01

    About 30-40 percent of the expected number of baryons is still missing in the local Universe (z \\lesssim 0.4). They are predicted to be hiding in a web of intergalactic gas at temperatures of about 10^5-10^7 K (the WHIM). Detecting this matter has had limited success so far, because of its low-density and high temperature, which makes it difficult to detect with current far-ultraviolet and X-ray instrumentation. Here we present the first results from our pilot 500 ks Chandra-LETG observation of the soft X-ray brightest source in the z > 0.4 sky, the blazar 1ES 1553+113. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2-4.1 sigma. Six of these lines are detected at high significance (3.6 < \\sigma < 4.1), while the remaining five are regarded as marginal detections in association with either other X-ray lines detected at higher significance and/or FUV signposts. Three of these lines are consistent with metal absorption at z~0. The remaining 8 lines...

  10. Evidence for ultra-fast outflows in radio-quiet AGNs. I. Detection and statistical incidence of Fe K-shell absorption lines

    Science.gov (United States)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G. G. C.; Yaqoob, T.; Braito, V.; Dadina, M.

    2010-10-01

    Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown massive and highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/outflows. Aims: The scope of the present work is to statistically quantify the parameters and incidence of the blue-shifted Fe K absorption lines through a uniform analysis on a large sample of radio-quiet AGNs. This allows us to assess their global detection significance and to overcome any possible publication bias. Methods: We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. A simple uniform model composed by an absorbed power-law plus Gaussian emission and absorption lines provided a good fit for all the data sets. We derived the absorption lines parameters and calculated their detailed detection significance making use of the classical F-test and extensive Monte Carlo simulations. Results: We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies higher than 7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3 × 10-8, and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability UFOs) those highly ionized absorbers with outflow velocities higher than 104 km s-1, then the majority of the lines are consistent with being associated to UFOs and the fraction of objects with detected UFOs in the whole sample is at least ~35%. This fraction is similar for type 1 and type 2 sources. The global covering fraction of

  11. Use of a bisphenol-A imprinted polymer as a selective sorbent for the determination of phenols and phenoxyacids in honey by liquid chromatography with diode array and tandem mass spectrometric detection.

    Science.gov (United States)

    Herrero-Hernández, E; Carabias-Martínez, R; Rodríguez-Gonzalo, E

    2009-09-21

    An extraction-preconcentration procedure based on the use of a molecularly imprinted polymer (MIP) as selective sorbent has been developed for the determination of several phenolic compounds (bisphenol-A, bisphenol-F and 4-nitrophenol) and phenoxyacid herbicides (2,4-D, 2,4,5-T and 2,4,5-TP) in honey samples. Liquid chromatography with diode array detection (LC-DAD) and electrospray ionisation-ion trap mass spectrometry (LC-IT-MS) were used for the separation, identification and quantification of these analytes. The molecularly imprinted polymer was obtained by precipitation polymerisation with bisphenol-A (BPA) as template and 4-vinylpyridine as the functional monomer. The behaviour of this sorbent was compared with those of other materials frequently used in SPE. The selectivity of the BPA-MIP for the target analytes was tested in samples containing other pesticides in common use. The recoveries achieved for all six compounds were in the 81-96% range. By applying the proposed procedure prior to LC-IT-MS, the limits of detection achieved in commercial honey samples were in the 0.1-3.8 ng g(-1) range, with relative standard deviations of 12-24%.

  12. Giant Metrewave Radio Telescope detection of associated H I 21-cm absorption at z = 1.2230 towards TXS 1954+513

    Science.gov (United States)

    Aditya, J. N. H. S.; Kanekar, Nissim; Prochaska, J. Xavier; Day, Brandon; Lynam, Paul; Cruz, Jocelyn

    2017-03-01

    We have used the 610-MHz receivers of the Giant Metrewave Radio Telescope (GMRT) to detect associated H I 21-cm absorption from the z = 1.2230 blazar TXS 1954+513. The GMRT H I 21-cm absorption is likely to arise against either the milliarcsecond-scale core or the one-sided milliarcsecond-scale radio jet, and is blueshifted by ≈328 km s-1 from the blazar redshift. This is consistent with a scenario in which the H I cloud giving rise to the absorption is being driven outwards by the radio jet. The integrated H I 21-cm optical depth is (0.716 ± 0.037) km s-1, implying a high H I column density, N_{H I} = (1.305 ± 0.067) × ({ T_s/100 K}) × 10^{20} cm-2, for an assumed H I spin temperature of 100 K. We use Nickel Telescope photometry of TXS 1954+513 to infer a high rest-frame 1216 Å luminosity of (4.1 ± 1.2) × 1023 W Hz-1. The z = 1.2230 absorber towards TXS 1954+513 is only the fifth case of a detection of associated H I 21-cm absorption at z > 1, and is also the first case of such a detection towards an active galactic nucleus (AGN) with a rest-frame ultraviolet (UV) luminosity ≫1023 W Hz-1, demonstrating that neutral hydrogen can survive in AGN environments in the presence of high UV luminosities.

  13. Nonlinear absorption coefficient and optically detected electrophonon resonance in cylindrical GaAs/AlAs quantum wires with different confined phonon models

    Science.gov (United States)

    Khoa, Doan Quoc; Phuong, Le Thi Thu; Hoi, Bui Dinh

    2017-03-01

    A quantum kinetic equation for electrons interacting with confined phonons is used to investigate the nonlinear absorption of an intense electromagnetic wave by electrons in cylindrical GaAs/AlAs quantum wires. The analytic expression for absorption coefficient is calculated for three models of confined optical phonons: the dielectric continuum (DC), hydrodynamic continuum (HC), and Huang-Zhu (HZ) models. The absorption coefficient depends on the square of the electromagnetic wave amplitude. The electrophonon resonance and optically detected electrophonon resonance (ODEPR) are observed through the absorption spectrum. The full width at half maximum (the line-width) of the ODEPR peaks is obtained by a computational method. The line-width is found to increase with increasing temperature and decrease with increasing the quantum wire radius. In particular, numerical results show that the DC and HZ models lead to a similar behaviour of electron - confined phonon interaction whereas the HC model results in a quite different one, especially at small quantum wire radius. For large quantum wire radii, above mentioned phonon models have equivalent contributions to the ODEPR line-width.

  14. Probing Cu(I) in homogeneous catalysis using high-energy-resolution fluorescence-detected X-ray absorption spectroscopy.

    Science.gov (United States)

    Walroth, Richard C; Uebler, Jacob W H; Lancaster, Kyle M

    2015-06-18

    Metal-to-ligand charge transfer excitations in Cu(I) X-ray absorption spectra are introduced as spectroscopic handles for the characterization of species in homogeneous catalytic reaction mixtures. Analysis is supported by correlation of a spectral library to calculations and to complementary spectroscopic parameters.

  15. NEW PERSPECTIVE ON GALAXY OUTFLOWS FROM THE FIRST DETECTION OF BOTH INTRINSIC AND TRAVERSE METAL-LINE ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Kacprzak, Glenn G.; Cooke, Jeff [Swinburne University of Technology, Victoria 3122 (Australia); Martin, Crystal L.; Ho, Stephanie H. [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Bouché, Nicolas; LeReun, Audrey; Schroetter, Ilane [CNRS, Institut de Recherche en Astrophysique et Planétologie (IRAP) de Toulouse, 14 Avenue E. Belin, F-31400 Toulouse (France); Churchill, Christopher W.; Klimek, Elizabeth, E-mail: gkacprzak@astro.swin.edu.au [New Mexico State University, Las Cruces, NM 88003 (United States)

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Lyα, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V {sub dtb} = 45-255 km s{sup –1}. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V {sub outflow} = 40-80 km s{sup –1} to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V {sub dtb}. The galaxy has a metallicity, derived from Hα and N II, of [O/H] = –0.21 ± 0.08, whereas the transverse absorption has [X/H] = –1.12 ± 0.02. The galaxy star formation rate is constrained between 4.6-15 M {sub ☉} yr{sup –1} while the estimated outflow rate ranges between 1.6-4.2 M {sub ☉} yr{sup –1} and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ∼1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  16. Femtosecond time-resolved X-ray absorption spectroscopy of liquid using a hard X-ray free electron laser in a dual-beam dispersive detection method.

    Science.gov (United States)

    Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

    2014-01-13

    We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 μm in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 μJ, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived.

  17. Simultaneous derivatization and extraction of chlorophenols in water samples with up-and-down shaker-assisted dispersive liquid-liquid microextraction coupled with gas chromatography/mass spectrometric detection.

    Science.gov (United States)

    Wang, Ke-Deng; Chen, Pai-Shan; Huang, Shang-Da

    2014-03-01

    A new up-and-down shaker-assisted dispersive liquid-liquid microextraction (UDSA-DLLME) for extraction and derivatization of five chlorophenols (4-chlorophenol, 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2,4,6-trichloro-phenol, and pentachlorophenol) has been developed. The method requires minimal solvent usage. The relatively polar, water-soluble, and low-toxicity solvent 1-heptanol (12 μL) was selected as the extraction solvent and acetic anhydride (50 μL) as the derivatization reagent. With the use of an up-and-down shaker, the emulsification of aqueous samples was formed homogeneously and quickly. The derivatization and extraction of chlorophenols were completed simultaneously in 1 min. The common requirement of disperser solvent in DLLME could be avoided. After optimization, the linear range covered over two orders of magnitude, and the coefficient of determination (r (2)) was greater than 0.9981. The detection limit was from 0.05 to 0.2 μg L(-1), and the relative standard deviation was from 4.6 to 10.8 %. Real samples of river water and lake water had relative recoveries from 90.3 to 117.3 %. Other emulsification methods such as vortex-assisted, ultrasound-assisted, and manual shaking-enhanced ultrasound-assisted methods were also compared with the proposed UDSA-DLLME. The results revealed that UDSA-DLLME performed with higher extraction efficiency and precision compared with the other methods.

  18. Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

    Directory of Open Access Journals (Sweden)

    Gang Zhao

    2016-09-01

    Full Text Available A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS instrumentation, based on a distributed feedback (DFB diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN. The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz, followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS can be swiftly performed down to a limit of detection (LOD (1σ of 4 × 10−6, which opens up a number of new applications.

  19. Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

    Science.gov (United States)

    Zhao, Gang; Tan, Wei; Jia, Mengyuan; Hou, Jiajuan; Ma, Weiguang; Dong, Lei; Zhang, Lei; Feng, Xiaoxia; Wu, Xuechun; Yin, Wangbao; Xiao, Liantuan; Axner, Ove; Jia, Suotang

    2016-01-01

    A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS) instrumentation, based on a distributed feedback (DFB) diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN). The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz), followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS) can be swiftly performed down to a limit of detection (LOD) (1σ) of 4 × 10−6, which opens up a number of new applications. PMID:27657082

  20. The HI absorption "Zoo"

    NARCIS (Netherlands)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-01-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis o

  1. Study on the Optimum Condition of Gas Chromatography Mass Spectrometric Detection for Zanthoxylum Essential Oil%气相-质谱联用法检测花椒挥发油条件优化的研究

    Institute of Scientific and Technical Information of China (English)

    罗凯; 黄秀芳; 胡江; 王洪伟; 阚建全

    2013-01-01

    Zanthoxylum essential oil by gas chromatography mass spectrometry detection conditions had been optimized in this page.Result:GC conditions:Rtx-Wax capillary column,(0.25 μm × 30 m × 0.32 mm,100% PEG stationary phase) ; programmed temperature,column temperature 40 ℃,maintained 1 min,3 ℃/min rose to 65 ℃,then 10 ℃/min rose to 90 ℃,and then 1.5 ℃/min rose to 120 ℃,finally 10 ℃/min rose to 230 ℃,maintained 5 min; split ratio 25∶1 ; carrier gas was high purity He,column pressure of 50 kPa,the flow rate of 1.0 mL/min ; injection port temperature of 250 ℃ ; interface temperature of 250 ℃ ; solvent delay time of 2.5 minutes.MS conditions:EI electron source,ion source temperature of 220 ℃,scan range 35 ~ 450 m/z,the standard library NIST05,which have good Precision,repeatability and stability.The optimization results for zanthoxylum essential Oil detection and zanthoxylum quality identification provides an experimental basis.%本试验对花椒挥发油气相色谱检测的条件进行了优化.优化结果:石英毛细管柱Rtx-Wax(0.25 μm×30 m×0.32 mm,100%聚乙二醇固定相);程序升温,柱温40℃,保持1min,以3℃/min升至65℃,再以10℃/min升至90℃,然后以1.5℃/min升至120℃,最后以10℃/min升至230℃,保持5 min;分流比25∶1;载气为高纯He,柱前压为50 kPa,流速为1.0 mL/min;进样口温度250℃;接口温度250℃;溶剂延迟时间2.5 min.质谱条件:EI电子源,离子源温度220℃,扫描范围35~450 m/z,标准图库NIST05.方法学考察显示该条件下,其精密性、重复性和稳定性良好.该优化结果为花椒挥发油的检测和花椒品质鉴定提供了试验依据

  2. High-throughput sequential injection method for simultaneous determination of plutonium and neptunium in environmental solids using macroporous anion-exchange chromatography, followed by inductively coupled plasma mass spectrometric detection.

    Science.gov (United States)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per; Miró, Manuel

    2011-01-01

    This paper reports an automated analytical method for rapid and simultaneous determination of plutonium and neptunium in soil, sediment, and seaweed, with detection via inductively coupled plasma mass spectrometry (ICP-MS). A chromatographic column packed with a macroporous anion exchanger (AG MP-1 M) was incorporated in a sequential injection (SI) system for the efficient retrieval of plutonium, along with neptunium, from matrix elements and potential interfering nuclides. The sorption and elution behavior of plutonium and neptunium onto AG MP-1 M resin was compared with a commonly utilized AG 1-gel-type anion exchanger. Experimental results reveal that the pore structure of the anion exchanger plays a pivotal role in ensuring similar separation behavior of plutonium and neptunium along the separation protocol. It is proven that plutonium-242 ((242)Pu) performs well as a tracer for monitoring the chemical yield of neptunium when using AG MP-1 M resin, whereby the difficulties in obtaining a reliable and practicable isotopic neptunium tracer are overcome. An important asset of the SI setup is the feasibility of processing up to 100 g of solid substrates using a small-sized (ca. 2 mL) column with chemical yields of neptunium and plutonium being ≥79%. Analytical results of three certified/standard reference materials and two solid samples from intercomparison exercises are in good agreement with the reference values at the 0.05 significance level. The overall on-column separation can be completed within 3.5 h for 10 g of soil samples. Most importantly, the anion-exchange mini-column suffices to be reused up to 10-fold with satisfactory chemical yields (>70%), as demanded in environmental monitoring and emergency scenarios, making the proposed automated assembly well-suited for unattended and high-throughput analysis.

  3. Detection of Highly Ionized Metal Absorption Lines in the Ultracompact X-ray Dipper 4U 1916-05

    CERN Document Server

    Juett, A M; Juett, Adrienne M.; Chakrabarty, Deepto

    2006-01-01

    We present the high-resolution Chandra X-ray Observatory persistent (non-dip) spectrum of 4U 1916-05 which revealed narrow absorption lines from hydrogenic neon, magnesium, silicon, and sulfur, in addition to the previous identified hydrogenic and helium-like iron absorption lines. This makes 4U 1916-05 only the second of the classical X-ray dipper systems to show narrow absorption lines from elements other than iron. We propose two possible explanations for the small measured line widths (>~ 500-2000 km s^{-1}), compared to the expected Keplerian velocities (> 1000 km s^{-1}) of the accretion disk in this 50-min orbital period system, and lack of wavelength shifts (>~ 250 km s^{-1}). First, the ionized absorber may be stationary. Alternatively, the line properties may measure the relative size of the emission region. From this hypothesis, we find that the emission region is constrained to be >~ 0.25 times the radial extent of the absorber. Our results also imply that the ionized absorber spans a range of ion...

  4. Detection of High Velocity Absorption Components in the He I Lines of Eta Carinae near the Time of Periastron

    Science.gov (United States)

    Richardson, Noel D.; St-Jean, Lucas; Gull, Theodore R.; Madura, Thomas; Hillier, D. John; Teodoro, Mairan; Moffat, Anthony; Corcoran, Michael; Damineli, Augusto

    2014-01-01

    We have obtained a total of 58 high spectral resolution (R90,000) 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 45507500A region. We have increased our monitoring efforts and observation frequency as the periastron event of 2014 has approached. We note that there were multiple epochs this year where we observe unusual absorption components in the P Cygni troughs of the He I triplet lines. In particular, we note high velocity absorption components related to the following epochs for the following lines: He I 4713: HJD 2456754- 2456795 (velocity -450 to -560 kms) He I 5876: HJD 2456791- 2456819 (velocity -690 to -800 kms) He I 7065: HJD 2456791- 2456810 (velocity -665 to -730 kms) Figures: Note that red indicates a high-velocity component noted above. He I 4713: http:www.astro.umontreal.carichardson4713.png He I 5876: http:www.astro.umontreal.carichardson5876.png He I 7065: http:www.astro.umontreal.carichardson7065.png These absorptions are likely related to the wind-wind collision region and bow shock, as suggested by the high-velocity absorption observed by Groh et al. (2010, AA, 519, 9) in the He I 10830 Atransition. In these cases, we suspect that we look along an arm of the shock cone and that we will see a fast absorption change from the other collision region shortly after periastron. We suspect that this is related to the multiple-components of the He II 4686 line that was noted by Walter (ATel6334), and is confirmed in our data. 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

  5. Detection of water absorption in the dayside atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 microns

    CERN Document Server

    Birkby, J L; Brogi, M; de Mooij, E J W; Schwarz, H; Albrecht, S; Snellen, I A G

    2013-01-01

    We report a 5 sigma detection of water absorption features in the dayside spectrum of the hot Jupiter HD 189733 b. We used high-resolution (R~100,000) spectra taken at 3.2 microns with CRIRES on the VLT to trace the radial velocity shift of the water features in the planet's dayside atmosphere during 5 hours of its 2.2 day orbit as it approached secondary eclipse. Despite considerable telluric contamination in this wavelength regime, we detect the signal within our uncertainties at the expected combination of systemic velocity (Vsys=-3 +5-6 km/s) and planet orbital velocity (Kp=154 +14-10 km/s), and determine a H2O line contrast ratio of (1.3+/-0.2)x10^-3 with respect to the stellar continuum. We find no evidence of significant absorption or emission from other carbon-bearing molecules, such as methane, although we do note a marginal increase in the significance of our detection with the inclusion of carbon dioxide in our template spectrum. This result demonstrates that ground-based, high-resolution spectrosc...

  6. Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Hongming [Laboratoire de Physicochimie de l' Atmosphère, Université du Littoral Côte d' Opale, 189A, Av. Maurice Schumann, 59140 Dunkerque (France); Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 1125, 350 Shushanhu Road, Hefei, Anhui 230031 (China); Maamary, Rabih; Fertein, Eric; Chen, Weidong, E-mail: chen@univ-littoral.fr [Laboratoire de Physicochimie de l' Atmosphère, Université du Littoral Côte d' Opale, 189A, Av. Maurice Schumann, 59140 Dunkerque (France); Gao, Xiaoming [Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 1125, 350 Shushanhu Road, Hefei, Anhui 230031 (China); Sigrist, Markus W. [ETH Zurich, Institute for Quantum Electronics, HPT H4.1, Auguste-Piccard-Hof 1, CH-8093 Zürich (Switzerland)

    2015-03-09

    Spectroscopic detection of short-lived gaseous nitrous acid (HONO) at 1254.85 cm{sup −1} was realized by off-beam coupled quartz-enhanced photoacoustic spectroscopy (QEPAS) in conjunction with an external cavity quantum cascade lasers (EC-QCL). High sensitivity monitoring of HONO was performed within a very small gas-sample volume (of ∼40 mm{sup 3}) allowing a significant reduction (of about 4 orders of magnitude) of air sampling residence time which is highly desired for accurate quantification of chemically reactive short-lived species. Calibration of the developed QEPAS-based HONO sensor was carried out by means of lab-generated HONO samples whose concentrations were determined by direct absorption spectroscopy involving a ∼109.5 m multipass cell and a distributed feedback QCL. A minimum detection limit (MDL) of 66 ppbv (1 σ) HONO was achieved at 70 mbar using a laser output power of 50 mW and 1 s integration time, which corresponded to a normalized noise equivalent absorption coefficient of 3.6 × 10{sup −8 }cm{sup −1} W/Hz{sup 1/2}. This MDL was down to 7 ppbv at the optimal integration time of 150 s. The corresponding 1σ minimum detected absorption coefficient is ∼1.1 × 10{sup −7 }cm{sup −1} (MDL ∼ 3 ppbv) in 1 s and ∼1.1 × 10{sup −8 }cm{sup −1} (MDL ∼ 330 pptv) in 150 s, respectively, with 1 W laser power.

  7. Grazing-angle fiber-optic fourier transform infrared reflection-absorption spectroscopy for the in situ detection and quantification of two active pharmaceutical ingredients on glass.

    Science.gov (United States)

    Perston, Benjamin B; Hamilton, Michelle L; Williamson, Bryce E; Harland, Peter W; Thomson, Mary A; Melling, Peter J

    2007-02-01

    Fourier transform infrared reflection-absorption spectroscopy has been used with a fiber-optic grazing-angle reflectance probe as a rapid, in situ method for trace surface analysis of acetaminophen and aspirin at loadings of approximately 0-2 microg cm(-2) on glass. Partial least-squares multivariate regression permits the loadings to be quantified, simultaneously, with root-mean-squared errors of prediction of RMSEP approximately 0.1 microg cm(-2) for both compounds. The detection limits are estimated to be LD approximately 0.2 microg cm(-2).

  8. Detection of lead in Zea mays by dual-energy X-ray microtomography at the SYRMEP beamline of the ELETTRA synchrotron and by atomic absorption spectroscopy.

    Science.gov (United States)

    Reale, Lucia; Kaiser, Jozef; Pace, Loretta; Lai, Antonia; Flora, Francesco; Angelosante Bruno, Antonella; Tucci, Adele; Zuppella, Paola; Mancini, Lucia; Tromba, Giuliana; Ruggieri, Fabrizio; Fanelli, Maria; Malina, Radomir; Liska, Miroslav; Poma, Anna

    2010-06-01

    This study is related to the application of the X-ray dual-energy microradiography technique together with the atomic absorption spectroscopy (AAS) for the detection of lead on Zea mays stem, ear, root, and leaf samples. To highlight the places with lead intake, the planar radiographs taken with monochromatic X-ray radiation in absorption regime with photon energy below and above the absorption edge of a given chemical element, respectively, are analyzed and processed. To recognize the biological structures involved in the intake, the dual-energy images with the lead signal have been compared with the optical images of the same Z. mays stem. The ear, stem, root, and leaf samples have also been analyzed with the AAS technique to measure the exact amount of the hyperaccumulated lead. The AAS measurement revealed that the highest intake occurred in the roots while the lowest in the maize ears and in the leaf. It seems there is a particular mechanism that protects the seeds and the leaves in the intake process.

  9. Detection of Candida albicans by mass spectrometric fingerprinting.

    Science.gov (United States)

    Zehm, Sarah; Schweinitz, Simone; Würzner, Reinhard; Colvin, Hans Peter; Rieder, Josef

    2012-03-01

    Candida albicans is one of the most frequent causes of fungal infections in humans. Significant correlation between candiduria and invasive candidiasis has previously been described. The existing diagnostic methods are often time-consuming, cost-intensive and lack in sensitivity and specificity. In this study, the profile of low-molecular weight volatile compounds in the headspace of C. albicans-urine suspensions of four different fungal cell concentrations compared to nutrient media and urine without C. albicans was determined using proton-transfer reaction mass spectrometry (PTR-MS). At fungal counts of ≥1.5 × 10(5) colony forming units (CFU)/ml signals at 45, 47 and 73 atomic mass units (amu) highly significantly increased. At fungal counts of albicans-urine suspensions of different fungal cell concentrations. PTR-MS represents a promising approach to rapid, highly sensitive and non-invasive clinical diagnostics allowing qualitative and quantitative analysis.

  10. Analysis of Marine Biotoxins by Liquid Chromatography Mass Spectrometric Detection

    NARCIS (Netherlands)

    Gerssen, A.

    2014-01-01

    The last few years have brought about many changes in the field of marine and freshwater toxins, with advances in analytical technology and the realization that these toxins are a global issue. Offering a complete reference guide, Seafood and Freshwater Toxins: Pharmacology, Physiology, and Detectio

  11. Mass Spectrometric Approaches to Detecting and Quantifying Prions

    Science.gov (United States)

    Until recently, the use of mass spectrometry has been limited to identifying covalent posttranslational modifications of PrPSc and PrPC. These efforts support the hypothesis that PrPC and PrPSc possess identical covalent posttranslational modifications. Technical advances in instrumentation now all...

  12. Mass Spectrometric Approaches to Detecting and Quantifying Prions

    Science.gov (United States)

    Prions are infectious proteins that replicate by converting a normal cellular protein (PrPC)into a prion. Although prions and PrPC are isoforms, they have dramatically different physicochemical properties. Prions are resistant to proteinase K (PK) degradation, while PrPC is completely degraded by PK...

  13. Ambient aerodynamic ionization source for remote analyte sampling and mass spectrometric analysis.

    Science.gov (United States)

    Dixon, R Brent; Sampson, Jason S; Hawkridge, Adam M; Muddiman, David C

    2008-07-01

    The use of aerodynamic devices in ambient ionization source development has become increasingly prevalent in the field of mass spectrometry. In this study, an air ejector has been constructed from inexpensive, commercially available components to incorporate an electrospray ionization emitter within the exhaust jet of the device. This novel aerodynamic device, herein termed remote analyte sampling, transport, and ionization relay (RASTIR) was used to remotely sample neutral species in the ambient and entrain them into an electrospray plume where they were subsequently ionized and detected using a linear ion trap Fourier transform mass spectrometer. Two sets of experiments were performed in the ambient environment to demonstrate the device's utility. The first involved the remote (approximately 1 ft) vacuum collection of pure sample particulates (i.e., dry powder) from a glass slide, entrainment and ionization at the ESI emitter, and mass spectrometric detection. The second experiment involved the capture (vacuum collection) of matrix-assisted laser desorbed proteins followed by entrainment in the ESI emitter plume, multiple charging, and mass spectrometric detection. This approach is in principle a RASTIR-assisted matrix-assisted laser desorption electrospray ionization source (Sampson, J. S.; Hawkridge, A. M.; Muddiman, D. C. J. Am. Soc. Mass Spectrom. 2006, 17, 1712-1716; Rapid Commun. Mass Spectrom. 2007, 21, 1150-1154.). A detailed description of the device construction, operational parameters, and preliminary small molecule and protein data are presented.

  14. In situ probing of cholesterol in astrocytes at the single-cell level using laser desorption ionization mass spectrometric imaging with colloidal silver.

    Science.gov (United States)

    Perdian, D C; Cha, Sangwon; Oh, Jisun; Sakaguchi, Donald S; Yeung, Edward S; Lee, Young Jin

    2010-04-30

    Mass spectrometric imaging has been utilized to localize individual astrocytes and to obtain cholesterol populations at the single-cell level in laser desorption ionization (LDI) with colloidal silver. The silver ion adduct of membrane-bound cholesterol was monitored to detect individual cells. Good correlation between mass spectrometric and optical images at different cell densities indicates the ability to perform single-cell studies of cholesterol abundance. The feasibility of quantification is confirmed by the agreement between the LDI-MS ion signals and the results from a traditional enzymatic fluorometric assay. We propose that this approach could be an effective tool to study chemical populations at the cellular level.

  15. [Detection of common determinants of HLA antigens A2 and B17 by absorption using human HLA serum].

    Science.gov (United States)

    Májský, A; Korínková, P

    1983-01-01

    Attempts of cross absorption where sera of anti-HLA A2 + B17, anti-HLA A2 and anti-HLA B17 with thrombocytes were absorbed from donors of HLA A2 positive, B17 negative and HLA A2 negative, B17 positive, revealed that anti-HLA A2 and anti-HLA B17 could be eliminated from the sera of both HLA types on the platelets. Thus, the findings allow the existence of a common determinant of HLA A2 and B17-antigens to be assumed. This is the first case where the evidence of a cross reaction between antigens of two different HLA loci with human sera could be established.

  16. Experimental characterization of the Clear-PEM scanner spectrometric performance

    Science.gov (United States)

    Bugalho, R.; Carriço, B.; Ferreira, C. S.; Frade, M.; Ferreira, M.; Moura, R.; Ortigão, C.; Pinheiro, J. F.; Rodrigues, P.; Rolo, I.; Silva, J. C.; Trindade, A.; Varela, J.

    2009-10-01

    In the framework of the Clear-PEM project for the construction of a high-resolution and high-specificity scanner for breast cancer imaging, a Positron Emission Mammography tomograph has been developed and installed at the Instituto Português de Oncologia do Porto hospital. The Clear-PEM scanner is mainly composed by two planar detector heads attached to a robotic arm, trigger/data acquisition electronics system and computing servers. The detector heads hold crystal matrices built from 2 × 2 × 20 mm3 LYSO:Ce crystals readout by Hamamatsu S8550 APD arrays. The APDs are optically coupled to both ends of the 6144 crystals in order to extract the DOI information for each detected event. Each one of 12288 APD's pixels is read and controlled by Application Specific Integrated Circuits water-cooled by an external cooling unit. The Clear-PEM frontend boards innovative design results in a unprecedented integration of the crystal matrices, APDs and ASICs, making Clear-PEM the PET scanner with the highest number of APD pixels ever integrated so far. In this paper, the scanner's main technical characteristics, calibration strategies and the first spectrometric performance evaluation in a clinical environment are presented. The first commissioning results show 99.7% active channels, which, after calibration, have inter-pixel and absolute gain distributions with dispersions of, respectively, 12.2% and 15.3%, demonstrating that despite the large number of channels, the system is uniform. The mean energy resolution at 511 keV is of 15.9%, with a 8.8% dispersion, and the mean CDOI-1 is 5.9%/mm, with a 7.8% dispersion. The coincidence time resolution, at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM.

  17. Experimental characterization of the Clear-PEM scanner spectrometric performance

    Energy Technology Data Exchange (ETDEWEB)

    Bugalho, R; Carrico, B; Ferreira, C S; Frade, M; Ferreira, M; Moura, R; Ortigao, C; Pinheiro, J F; Rodrigues, P; Rolo, I; Silva, J C; Trindade, A; Varela, J [Laboratorio de Instrumentacao e Fisica Experimental de Particulas (LIP), Av. Elias Garcia 14-1, 1000-149 Lisboa (Portugal)], E-mail: frade@lip.pt

    2009-10-15

    In the framework of the Clear-PEM project for the construction of a high-resolution and high-specificity scanner for breast cancer imaging, a Positron Emission Mammography tomograph has been developed and installed at the Instituto Portugues de Oncologia do Porto hospital. The Clear-PEM scanner is mainly composed by two planar detector heads attached to a robotic arm, trigger/data acquisition electronics system and computing servers. The detector heads hold crystal matrices built from 2 x 2 x 20 mm{sup 3} LYSO:Ce crystals readout by Hamamatsu S8550 APD arrays. The APDs are optically coupled to both ends of the 6144 crystals in order to extract the DOI information for each detected event. Each one of 12288 APD's pixels is read and controlled by Application Specific Integrated Circuits water-cooled by an external cooling unit. The Clear-PEM frontend boards innovative design results in a unprecedented integration of the crystal matrices, APDs and ASICs, making Clear-PEM the PET scanner with the highest number of APD pixels ever integrated so far. In this paper, the scanner's main technical characteristics, calibration strategies and the first spectrometric performance evaluation in a clinical environment are presented. The first commissioning results show 99.7% active channels, which, after calibration, have inter-pixel and absolute gain distributions with dispersions of, respectively, 12.2% and 15.3%, demonstrating that despite the large number of channels, the system is uniform. The mean energy resolution at 511 keV is of 15.9%, with a 8.8% dispersion, and the mean C{sub DOI}{sup -1} is 5.9%/mm, with a 7.8% dispersion. The coincidence time resolution, at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM.

  18. Water vapour emission in vegetable fuel: absorption cell measurements and detection limits of our CO II Dial system

    Science.gov (United States)

    Bellecci, C.; De Leo, L.; Gaudio, P.; Gelfusa, M.; Lo Feudo, T.; Martellucci, S.; Richetta, M.

    2006-09-01

    Forest fires can be the cause of serious environmental and economic damages. For this reason a considerable effort has been directed toward the forest protection and fire fighting. In the early forest fire detection, Lidar technique present considerable advantages compared to the passive detection methods based on infrared cameras currently in common use, due its higher sensitivity and ability to accurately locate the fire. The combustion phase of the vegetable matter causes a great amount of water vapour emission, thus the water molecule behaviour will be studied to obtain a fire detection system ready and efficient also before the flame propagation. A first evaluation of increment of the water vapour concentration compared to standard one will be estimated by a numerical simulation. These results will be compared with the experimental measurements carried out into a cell with a CO II Dial system, burning different kinds of vegetable fuel. Our results and their comparison will be reported in this paper.

  19. Comparison of Tunable Diode Laser Absorption Spectroscopy and Isothermal Micro-calorimetry for Non-invasive Detection of Microbial Growth in Media Fills

    Science.gov (United States)

    Brueckner, David; Roesti, David; Zuber, Ulrich Georg; Schmidt, Rainer; Kraehenbuehl, Stefan; Bonkat, Gernot; Braissant, Olivier

    2016-01-01

    Two methods were investigated for non-invasive microbial growth-detection in intact glass vials as possible techniques for automated inspection of media-filled units. Tunable diode laser absorption spectroscopy (TDLAS) was used to determine microbially induced changes in O2 and CO2 concentrations within the vial headspaces. Isothermal microcalorimetry (IMC) allowed the detection of metabolic heat production. Bacillus subtilis and Streptococcus salivarius were chosen as test organisms. Parameters as robustness, sensitivity, comparability and time to detection (TtD) were evaluated to assess method adequacy. Both methods robustly detected growth of the tested microorganisms within less than 76 hours using an initial inoculum of IMC, as some false negative results were observed. Compared to the visual media-fill examination of spiked samples, the investigated techniques were slightly slower regarding TtD. Although IMC showed shorter TtD than TDLAS the latter is proposed for automating the media-fill inspection, as larger throughput can be achieved. For routine use either TDLA or a combination of TDLA and TDLA should be considered. IMC may be helpful for replacing the sterility assessment of commercial drug products before release. PMID:27282661

  20. Detectors for the Gamma-Ray Resonant Absorption (GRA) Method of Explosives Detection in Cargo: A Comparative Study

    CERN Document Server

    Vartsky, D; Engler, G; Shor, A; Goldschmidt, A; Feldman, G; Bar, D; Orion, I; Wielopolski, L; Vartsky, David; Goldberg, Mark B.; Engler, Gideon; Shor, Asher; Goldschmidt, Aharon; Feldman, Gennady; Bar, Doron; Orion, Itzhak; Wielopolski, Lucian

    2004-01-01

    Gamma-Ray Resonant Absorption (GRA) is an automatic-decision radiographic screening technique that combines high radiation penetration with very good sensitivity and specificity to nitrogenous explosives. The method is particularly well-suited to inspection of large, massive objects (since the incident gamma-ray probe is at 9.17 MeV) such as aviation and marine containers, heavy vehicles and railroad cars. Two kinds of gamma-ray detectors have been employed to date in GRA systems: 1) Resonant-response nitrogen-rich liquid scintillators and 2) BGO detectors. This paper analyses and compares the response of these detector-types to the resonant radiation, in terms of single-pixel figures of merit. The latter are sensitive not only to detector response, but also to accelerator-beam quality, via the properties of the nuclear reaction that produces the resonant gamma-rays. Generally, resonant detectors give rise to much higher nitrogen-contrast sensitivity in the radiographic image than their non-resonant detector ...

  1. Ultrasound-assisted emulsification of cosmetic samples prior to elemental analysis by different atomic spectrometric techniques.

    Science.gov (United States)

    Lavilla, I; Cabaleiro, N; Costas, M; de la Calle, I; Bendicho, C

    2009-11-15

    In this work, ultrasound-assisted emulsification with a probe system is proposed as a rapid and simple sample treatment for atomic spectrometric determinations (Electrothermal Atomic Absorption Spectrometry, Inductively Coupled Plasma Optical Emission Spectrometry, Flame Atomic Absorption Spectrometry and Cold Vapour Atomic Absorption Spectrometry) of trace elements (As, Cd, Cr, Cu, Hg, Mg, Mn, Ni, Sr and Zn) in cosmetic samples such as shampoos, gel (hair gel), crèmes (body milk, hair conditioner) and oil (body oil). The type of dispersion medium, the sample mass-to-dispersion medium volume ratio, as well as the parameters related to the ultrasound-assisted emulsification (sonication amplitude and treatment time) were exhaustively studied. Only 1 min of ultrasonic shaking and a dispersion medium containing 0.5% (w/v) of SDS+3% (v/v) of HNO(3) or HCl allows obtaining a stable emulsion at least for 3 months. Thermal programs, nebulization of emulsions, speed of pumps and concentration of reagents used in cold vapour generation were optimized. Calibration using aqueous standards was feasible in all cases. Calibration by the standard addition method and recovery studies was also applied for validation. Microwave-assisted digestion and Inductively Coupled Plasma Mass Spectrometry were used for comparison purposes. Relative standard deviations from analysis of five independent emulsions were less than 9% in all cases.

  2. Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

  3. Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review

    Energy Technology Data Exchange (ETDEWEB)

    Herrero Latorre, C., E-mail: carlos.herrero@usc.es [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain); Alvarez Mendez, J.; Barciela Garcia, J.; Garcia Martin, S.; Pena Crecente, R.M. [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain)

    2012-10-24

    Highlights: Black-Right-Pointing-Pointer The use of CNTs as sorbent for metal species in solid phase extraction has been described. Black-Right-Pointing-Pointer Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. Black-Right-Pointing-Pointer Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes - due to their high adsorption and desorption capacities - have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

  4. Detection of para–antiferromagnetic transition in Bi{sub 2}Fe{sub 4}O{sub 9} powders by means of microwave absorption measurements

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G., E-mail: memodin@yahoo.com [Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, U.P.A.L.M, Edificio 9, Av. Instituto Politécnico Nacional S/N, San Pedro Zacatenco, México DF 07738 (Mexico); Contreras, J. [Facultad de Química de la Universidad Nacional Autónoma de México, Cd. Universitaria, México DF 04510 (Mexico); Conde-Gallardo, A. [Departamento de Física, CINVESTAV-IPN, A.P. 14-740, México DF 07360 (Mexico); Montiel, H., E-mail: herlinda_m@yahoo.com [Centro de Ciencias Aplicadas y Desarrollo Tecnológico de la Universidad Nacional Autónoma de México, Cd. Universitaria, A.P. 70-186, México DF 04510 (Mexico); Zamorano, R. [Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, U.P.A.L.M, Edificio 9, Av. Instituto Politécnico Nacional S/N, San Pedro Zacatenco, México DF 07738 (Mexico)

    2013-12-15

    An electron paramagnetic resonance (EPR) study of Bi{sub 2}Fe{sub 4}O{sub 9} powders is carried out in X-band (8.8–9.8 GHz) and the 200–350 K temperature range. For all the temperatures, the EPR spectra show a single broad line attributable to Fe{sup 3+} (S=5/2) ions. The onset of the para–antiferromagnetic transition has been determined from the temperature dependence of the parameters deduced from EPR spectra: the peak-to-peak linewidth (ΔH{sub pp}) and the resonant field (H{sub res}); a weak ferromagnetism is also observed at low temperature and it is attributed to canting of Fe{sup 3+} ion sublattices in the antiferromagnetic matrix. The magnetically modulated microwave absorption spectroscopy (MAMMAS) and the low-field microwave absorption (LFMA) are used to give further information on this material. These techniques give evidence of the magnetic transition, suggesting a weak ferromagnetism at low temperature. - Highlights: • The changes in lineshape of the EPR spectra in Bi{sub 2}Fe{sub 4}O{sub 9} powders are studied. • The onset of the para–antiferromagnetic transition is detected. • A weak ferromagnetism is also observed in this material. • MAMMAS and LFMA techniques are used to give a further knowledge on the bismuth ferrite.

  5. Determination of mercury in estuarine sediments by flow injection-cold vapour atomic absorption spectrometry after microwave extraction

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Garcia, M.L.; Carlosena, A.; Lopez-Mahia, P.; Muniategui, S.; Prada, D. [University of La Coruna (Spain). Dept. Analytical Chemistry

    1999-01-01

    A flow injection-cold vapour atomic absorption spectrometric (CVAAS) method was developed for the determination of mercury at trace level in estuarine sediments using sodium tetra-hydro-borate (III) as reductant. The mercury was solubilized with nitric acid in closed vessels nd microwave oven heating. Instrumental and operational conditions (volume and concentration of reagents, reaction time, etc.) were optimized. The effect of several ions on the analytical signal was also studied; no interferences were recorded excepting for copper and nickel which caused a serious depressing effect. The detection limit obtained was 0.01 {mu}g g{sup -1}. The validation of the method was performed analyzing a certified reference sediment, BCR CRM 277 Estuarine Sediment. Good recovery (c.a. 98 %) and precision (< 3 %, RSD) were achieved. The proposed method was successfully applied to the determination of mercury in sediment samples from Ares-Betanzos Estuary (Galicia, NW Spain). (authors) 19 refs.

  6. Detection and diagnosis of a natural gas dehydration plant by absorption with triethylene glycol, employing a artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The natural gas dehydration is a great importance operation in the gas and petroleum industry, It avoids operational problems associated with the water content, which appear frequently in the industrial facilities that use the natural gas as raw material or as work tool. Due to the presence of undesirable pollutants which may enter the plant with the wet natural gas current (lubricating, corrosion inhibitors, salts, and others), the equipment that constitutes the dehydration plants are capable to suffering operational faults as the heat exchangers fouling, foam formation in the absorber, glycol losses for dragging; trays, packings, valves and filters fouling; glycol degradation, inadequate temperatures of regeneration and others. The above mentioned faults often cannot be detected by the operators and engineers but up to the moment when a catastrophic damage occurs or when products are obtained out of specification, which causes big economic and time losses. By means of the application of artificial neural networks, there was achieved the detection and the effective diagnosis of faults, still in incipient state, in a gas dehydration plant. (author)

  7. A nonlinear merging method of analog and photon signals for CO2 detection in lower altitudes using differential absorption lidar

    Science.gov (United States)

    Qi, Zhong; Zhang, Teng; Han, Ge; Li, Dongcang; Ma, Xin; Gong, Wei

    2017-04-01

    The current acquisition system of a lidar detects return signals in two modes (i.e., analog and photon counting); resulting in the lower (below 1500 m) and upper (higher than 1100 m) atmospheric parameters need analog and photon counting signal to retrieve, respectively. Hence, a lidar cannot obtain a continuous column of the concentrations of atmospheric components. For carbon cycle studies, the range-resolved concentration of atmospheric CO2 in the lower troposphere (below 1500 m) is one of the most significant parameters that should be determined. This study proposes a novel gluing method that merges the CO2 signal detected by ground-based DIAL in the lower troposphere. Through simulation experiments, the best uniform approximation polynomial theorem is utilized to determine the transformation coefficient to correlate signals from the different modes perfectly. The experimental results (both simulation experiments and actual measurement of signals) show that the proposed method is suitable and feasible for merging data in the region below 1500 m. Hence, the photon-counting signals whose SNRs are higher than those of the analog signals can be used to retrieve atmospheric parameters at an increased near range, facilitating atmospheric soundings using ground-based lidar in various fields.

  8. Coumarin-based fluorescence hybrid silica material used for selective detection and absorption of Hg2+ in aqueous media

    Science.gov (United States)

    Meng, Qingtao; Jia, Hongmin; Wang, Cuiping; Zhao, Hongbin; Lu, Gonghao; Hu, Zhizhi; Zhang, Zhiqiang; Duan, Chunying

    2014-11-01

    An inorganic-organic hybrid fluorescence material (C-SBA-15) was prepared by covalent immobilization of a coumarin derivative within the channels of SBA-15. The characterization results of XRD, TEM micrographs, FT-IR and UV-vis demonstrate that coumarin is successfully grafted onto the inner surface of SBA-15 and its organized structure is preserved. C-SBA-15 can detect Hg2+ with high selectivity to Pb2+, Zn2+, Cu2+, Mn2+, Cd2+, Co2+, Ag+, Fe3+, Ni2+, K+, Na+, Ca2+, Mg2+ and Li+ in water. Furthermore, the fluorogenical response is reversible by treating with EDTA and do not vary over a broad pH range (5.0-10.5). C-SBA-15 features more outstanding absorbing capacity for Hg2+ among other HTM ions in water.

  9. The Bremen mass spectrometric facility for the measurement of helium isotopes, neon, and tritium in water.

    Science.gov (United States)

    Sültenfuss, Jürgen; Roether, Wolfgang; Rhein, Monika

    2009-06-01

    We describe the mass spectrometric facility for measuring helium isotopes, neon, and tritium that has been operative at this institute since 1989, and also the sampling and sample preparation steps that precede the mass spectrometric analysis. For water samples in a near-equilibrium with atmospheric air, the facility achieves precision for (3)He/(4)He ratios of+/-0.4% or better, and+/-0.8 % or better for helium and neon concentrations. Tritium precision is typically+/-3 % and the detection limit 10 mTU ( approximately 1.2.10(-3) Bq/kg of pure water). Sample throughputs can reach some thousands per year. These achievements are enabled, among other features, by automation of the measurement procedure and by elaborate calibration, assisted by continual development in detail. To date, we have measured more than 15,000 samples for tritium and 23,000 for helium isotopes and neon, mostly in the context of oceanographic and hydrologic work. Some results of such work are outlined. Even when atmospheric tritium concentrations have become rather uniform, tritium provides water ages if (3)He data are taken concurrently. The technique can resolve tritium concentrations in waters of the pre-nuclear era.

  10. Assessment of current mass spectrometric workflows for the quantification of low abundant proteins and phosphorylation sites

    Directory of Open Access Journals (Sweden)

    Manuel Bauer

    2015-12-01

    Full Text Available The data described here provide a systematic performance evaluation of popular data-dependent (DDA and independent (DIA mass spectrometric (MS workflows currently used in quantitative proteomics. We assessed the limits of identification, quantification and detection for each method by analyzing a dilution series of 20 unmodified and 10 phosphorylated synthetic heavy labeled reference peptides, respectively, covering six orders of magnitude in peptide concentration with and without a complex human cell digest background. We found that all methods performed very similarly in the absence of background proteins, however, when analyzing whole cell lysates, targeted methods were at least 5–10 times more sensitive than directed or DDA methods. In particular, higher stage fragmentation (MS3 of the neutral loss peak using a linear ion trap increased dynamic quantification range of some phosphopeptides up to 100-fold. We illustrate the power of this targeted MS3 approach for phosphopeptide monitoring by successfully quantifying 9 phosphorylation sites of the kinetochore and spindle assembly checkpoint component Mad1 over different cell cycle states from non-enriched pull-down samples. The data are associated to the research article ‘Evaluation of data-dependent and data-independent mass spectrometric workflows for sensitive quantification of proteins and phosphorylation sites׳ (Bauer et al., 2014 [1]. The mass spectrometry and the analysis dataset have been deposited to the ProteomeXchange Consortium (http://proteomecentral.proteomexchange.org via the PRIDE partner repository with the dataset identifier PXD000964.

  11. Infrared differential-absorption Mueller matrix spectroscopy and neural network-based data fusion for biological aerosol standoff detection.

    Science.gov (United States)

    Carrieri, Arthur H; Copper, Jack; Owens, David J; Roese, Erik S; Bottiger, Jerold R; Everly, Robert D; Hung, Kevin C

    2010-01-20

    An active spectrophotopolarimeter sensor and support system were developed for a military/civilian defense feasibility study concerning the identification and standoff detection of biological aerosols. Plumes of warfare agent surrogates gamma-irradiated Bacillus subtilis and chicken egg white albumen (analytes), Arizona road dust (terrestrial interferent), water mist (atmospheric interferent), and talcum powders (experiment controls) were dispersed inside windowless chambers and interrogated by multiple CO(2) laser beams spanning 9.1-12.0 microm wavelengths (lambda). Molecular vibration and vibration-rotation activities by the subject analyte are fundamentally strong within this "fingerprint" middle infrared spectral region. Distinct polarization-modulations of incident irradiance and backscatter radiance of tuned beams generate the Mueller matrix (M) of subject aerosol. Strings of all 15 normalized elements {M(ij)(lambda)/M(11)(lambda)}, which completely describe physical and geometric attributes of the aerosol particles, are input fields for training hybrid Kohonen self-organizing map feed-forward artificial neural networks (ANNs). The properly trained and validated ANN model performs pattern recognition and type-classification tasks via internal mappings. A typical ANN that mathematically clusters analyte, interferent, and control aerosols with nil overlap of species is illustrated, including sensitivity analysis of performance.

  12. Active Stand-off Detection of Gas Leaks Using a Short Range Hard-target Backscatter Differential Optical Absorption System Based on a Quantum Cascade Laser Transmitter

    Science.gov (United States)

    Diaz, Adrian; Thomas, Benjamin; Castillo, Paulo; Gross, Barry; Moshary, Fred

    2016-06-01

    Fugitive gas emissions from agricultural or industrial plants and gas pipelines are an important environmental concern as they can contribute to the global increase of greenhouse gas concentration. Moreover, they are also a security and safety concern because of possible risk of fire/explosion or toxicity. This study presents gas concentration measurements using a quantum cascade laser open path system (QCLOPS). The system retrieves the pathaveraged concentration of N2O and CH4 by collecting the backscattered light from a scattering target. The gas concentration measurements have a high temporal resolution (68 ms) and are achieved at sufficient range (up to 40 m, ~ 130 feet) with a detection limit of 2.6 ppm CH4 and 0.4 ppm for N2O. Given these characteristics, this system is promising for mobile/multidirectional remote detection and evaluation of gas leaks. The instrument is monostatic with a tunable QCL emitting at ~ 7.7 μm wavelength range. The backscattered radiation is collected by a Newtonian telescope and focused on an infrared light detector. Puffs of N2O and CH4 are released along the optical path to simulate a gas leak. The measured absorption spectrum is obtained using the thermal intra-pulse frequency chirped DFB QCL and is analyzed to obtain path averaged gas concentrations.

  13. Infrared absorption spectra of the CO(2)/H(2)O complex in a cryogenic nitrogen matrix--detection of a new bending frequency.

    Science.gov (United States)

    Zhang, Xu; Sander, Stanley P

    2011-09-08

    Infrared absorption spectra have been measured for the mixture of CO(2) and H(2)O in a cryogenic nitrogen matrix. The 1:1 CO(2)/H(2)O complex has been observed. Each structure of this complex should have two bending frequencies corresponding to the CO(2) fundamental bending mode (ν(2)). In this work, three bending frequencies corresponding to the CO(2) fundamental bending mode (ν(2)) have been detected; one of them at 660.3 cm(-1) is reported here for the first time. This finding helps confirm the existence of two structures for this complex. A new feature attributed to a CO(2) and H(2)O complex is observed at 3604.4 cm(-1) and is tentatively assigned to the CO(2)/H(2)O complex band corresponding to the CO(2) combination mode (ν(3) + 2ν(2)). In addition, a band that belongs to a CO(2) and H(2)O complex is detected at 3623.8 cm(-1) for the first time and is tentatively assigned to the (CO(2))(2)/H(2)O complex band corresponding to the symmetric stretching mode (ν(1)) of H(2)O.

  14. Determination of Cd(II, Zn(II and Ag(Iin different matrixes after solid phase extraction on sodium dodecyl sulfate(SDS-coated alumina as their 2,3 Di Hydro 2,3 paratolylQinazoline (1 H- 4 one (DPTQO by Flame atomic absorption spectrometric

    Directory of Open Access Journals (Sweden)

    Farveh Raoufi

    2016-03-01

    Full Text Available A sensitive and selective solid phase extraction procedure for the determination of traces of Cd(II, Zn(II and Ag(I ions has been developed. An alumina-sodium dodecyl sulfate (SDS coated on with 2,3 Di Hydro 2,3 paratolylQinazoline (1 H- 4 one (DPTQO. The influences of the analytical parameters including pH and sample volume were investigated.Common coexisting ions did not interfere on the separation and determination of analytes under study. The adsorbed analytes were desorbed by using 6mL of 4 mol L−1 nitric acid. The responses are linear 0.02–0.85 µg mL-1 for Cd2+ ion0.01–0.90 µg mL-1 for Zn2+and0.02–0.92µg mL-1for Ag+ detection limit for Cd(II, Zn(II and Ag(I ions were found to be 1.4, 1.3 and1.12(ng mL-1, respectively.It was found that the recovery for Cd2+, Zn2+and Ag+ ions were 97.7, 98.2 and 98.0 with RSD of 1.9, 1.8 and 1.7. It was also observed that recovery for repeated recovery on the same solid phase not varies more than 3%. The presented procedurewas successfully applied for determination of analytes in radiology wastewater, amalgam, natural water and blood samples.

  15. Absorption-line detections of 10{sup 5}-10{sup 6} K gas in spiral-rich groups of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Syphers, David; Yamamoto, H.; Shull, J. Michael; Green, James C.; Froning, Cynthia [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Savage, Blair D.; Wakker, Bart; Kim, Tae-Sun [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Ryan-Weber, Emma V.; Kacprzak, Glenn G., E-mail: john.stocke@colorado.edu [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, VIC 3122 (Australia)

    2014-08-20

    Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 'warm' (T ≥ 10{sup 5} K) absorbers using a combination of broad Lyα and broad O VI absorptions. A reanalysis of a few of this new class of absorbers using slightly relaxed fitting criteria finds as many as 20 warm absorbers could be present in this sample. A shallow, wide spectroscopic galaxy redshift survey has been conducted around these sight lines to investigate the warm absorber environment, which is found to be spiral-rich groups or cluster outskirts with radial velocity dispersions σ = 250-750 km s{sup –1}. While 2σ evidence is presented favoring the hypothesis that these absorptions are associated with the galaxy groups and not with the individual, nearest galaxies, this evidence has considerable systematic uncertainties and is based on a small sample size so it is not entirely conclusive. If the associations are with galaxy groups, the observed frequency of warm absorbers (dN/dz = 3.5-5 per unit redshift) requires them to be very extended as an ensemble on the sky (∼1 Mpc in radius at high covering factor). Most likely these warm absorbers are interface gas clouds whose presence implies the existence of a hotter (T ∼ 10{sup 6.5} K), diffuse, and probably very massive (>10{sup 11} M {sub ☉}) intra-group medium which has yet to be detected directly.

  16. Time-resolved in situ detection of CO in a shock tube using cavity-enhanced absorption spectroscopy with a quantum-cascade laser near 4.6 µm.

    Science.gov (United States)

    Sun, Kai; Wang, Shengkai; Sur, Ritobrata; Chao, Xing; Jeffries, Jay B; Hanson, Ronald K

    2014-10-06

    Cavity-enhanced absorption spectroscopy (CEAS) using a mid-infrared DFB quantum-cascade laser is reported for sensitive time-resolved (10 μs) in situ CO measurements in a shock tube. Off-axis alignment and fast scanning of the laser wavelength were used to minimize coupling noise in a low-finesse cavity. An absorption gain factor of 91 was demonstrated, which enabled sub-ppm detection sensitivity for gas temperatures of 1000-2100K in a 15 cm diameter shock tube. This substantial improvement in detection sensitivity compared to conventional single-pass absorption measurements, shows great potential for the study of reaction pathways of high-temperature combustion kinetics mechanisms in shock tubes.

  17. [Oil atomic spectrometric feature selection by Parzen window based vague sets theory].

    Science.gov (United States)

    Xu, Chao; Zhang, Pei-Lin; Ren, Guo-Quan; Zhang, Xiao-Dong; Yang, Yu-Dong

    2011-02-01

    Large quantity and ambiguity of oil atomic spectrometric information greatly affects the applicable efficiency and accuracy in fault diagnosis. A novel method for choosing less and effective spectrometric features is presented. Based on gearbox test bed, we simulated the normal wear state and two typical faults to acquire the lubricant samples. The three wear states are regarded as three vague sets, and spectrometric feature values are vague values on vague sets. Based on similarity between vague values, mean vague sensibility (MVS) is defined to describe the sensitive degree of spectrometric feature to wear state. Besides, the membership degrees of vague sets greatly depend on human experience. The probability density distribution of spectrometric data of three wear states was estimated with Parzen window. Combined with Bayesian formula, the range of vague sets membership was calculated. Experimental results verify that the proposed method is of efficient help in choosing high fault-sensitive features from so many spectrometric features.

  18. Determination of trace aluminum in biological and water samples by cloud point extraction preconcentration and graphite furnace atomic absorption spectrometry detection

    Energy Technology Data Exchange (ETDEWEB)

    Sang Hongbo [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China); Liang Pei [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China)], E-mail: liangpei@mail.ccnu.edu.cn; Du Dan [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China)

    2008-06-15

    A cloud point extraction (CPE) method for the preconcentration of trace aluminum prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) has been developed. The CPE method is based on the complex of Al(III) with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP), and then entrapped in non-ionic surfactant Triton X-114. PMBP was used not only as chelating reagent in CPE preconcentration, but also as chemical modifier in GFAAS determination. The main factors affecting CPE efficiency, such as pH of sample solution, concentration of PMBP and Triton X-114, equilibration temperature and time, were investigated in detail. An enrichment factor of 37 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of this method for Al(III) is 0.09 ng mL{sup -1}, and the relative standard deviation is 4.7% at 10 ng mL{sup -1} Al(III) level (n = 7). The proposed method has been applied for determination of trace amount of aluminum in biological and water samples with satisfactory results.

  19. Preconcentration of thallium (I) by single drop microextraction with electrothermal atomic absorption spectroscopy detection using dicyclohexano-18-crown-6 as extractant system.

    Science.gov (United States)

    Chamsaz, Mahmoud; Arbab-Zavar, Mohammad Hossien; Darroudi, Abolfazl; Salehi, Thiery

    2009-08-15

    A simple single drop liquid-phase microextraction (SDME) technique, combined with electrothermal atomic absorption spectroscopy (ETAAS) is developed both to preconcentrate and determine thallium (I) ions in aqueous solutions. The ions were transferred from 10.0 ml of aqueous sample (donor phase) containing 0.5 ml of 1% picric acid as the ion-pair agent into a 3 microl microdrop of nitrobenzene (acceptor phase) containing dicyclohexano-18-crown-6 as the complexing agent. The latter will help to improve the extraction efficiency of the analyte. After the ions have been extracted, the acceptor drop was directly injected into a graphite furnace for thallium (I) determination. Several parameters such as the extracting solvent, extraction time, temperature, concentration of picric acid and crown ether, drop volume and stirring rate were examined. Under the optimized experimental conditions, the detection limit (L.O.D.) was 0.7 ng ml(-1). The relative standard deviation for five replicate analysis of 10 ng ml(-1) of thallium (I) was 5.1%. The calibration curve was linear in the range of 3-22 ng ml(-1). The results for determination of thallium in reference material, spiked tap water and seawater demonstrated the accuracy, recovery and applicability of the presented method. The enrichment factor was 50.

  20. Infrared Absorption Spectra, Radiative Efficiencies, and Global Warming Potentials of Newly-Detected Halogenated Compounds: CFC-113a, CFC-112 and HCFC-133a

    Directory of Open Access Journals (Sweden)

    Maryam Etminan

    2014-07-01

    Full Text Available CFC-113a (CF3CCl3, CFC-112 (CFCl2CFCl2 and HCFC-133a (CF3CH2Cl are three newly detected molecules in the atmosphere that are almost certainly emitted as a result of human activity. It is important to characterise the possible contribution of these gases to radiative forcing of climate change and also to provide information on the CO2-equivalence of their emissions. We report new laboratory measurements of absorption cross-sections of these three compounds at a resolution of 0.01 cm−1 for two temperatures 250 K and 295 K in the spectral range of 600–1730 cm−1. These spectra are then used to calculate the radiative efficiencies and global warming potentials (GWP. The radiative efficiencies are found to be between 0.15 and 0.3 W∙m−2∙ppbv−1. The GWP for a 100 year time horizon, relative to carbon dioxide, ranges from 340 for the relatively short-lived HCFC-133a to 3840 for the longer-lived CFC-112. At current (2012 concentrations, these gases make a trivial contribution to total radiative forcing; however, the concentrations of CFC-113a and HCFC-133a are continuing to increase. The 2012 CO2-equivalent emissions, using the GWP (100, are estimated to be about 4% of the current global CO2-equivalent emissions of HFC-134a.

  1. A sensitive magnetic nanoparticle-based immunoassay of phosphorylated acetylcholinesterase using protein cage templated lead phosphate for signal amplification with graphite furnace atomic absorption spectrometry detection.

    Science.gov (United States)

    Liang, Pei; Kang, Caiyan; Yang, Enjian; Ge, Xiaoxiao; Du, Dan; Lin, Yuehe

    2016-04-01

    We developed a new magnetic nanoparticle sandwich-like immunoassay using protein cage nanoparticles (PCN) for signal amplification together with graphite furnace atomic absorption spectrometry (GFAAS) for the quantification of an organophosphorylated acetylcholinesterase adduct (OP-AChE), the biomarker of exposure to organophosphate pesticides (OPs) and nerve agents. OP-AChE adducts were firstly captured by titanium dioxide coated magnetic nanoparticles (TiO2-MNPs) from the sample matrixes through metal chelation with phospho-moieties, and then selectively recognized by anti-AChE antibody labeled on PCN which was packed with lead phosphate in its cavity (PCN-anti-AChE). The sandwich-like immunoreaction was performed among TiO2-MNPs, OP-AChE and PCN-anti-AChE to form a TiO2-MNP/OP-AChE/PCN-anti-AChE immunocomplex. The complex could be easily isolated from the sample solution with the help of magnet, and the released lead ions from PCN were detected by GFAAS for the quantification of OP-AChE. Greatly enhanced sensitivity was achieved because PCN increased the amount of metal ions in the cavity of each apoferritin. The proposed immunoassay yielded a linear response over a broad range of OP-AChE concentrations from 0.01 nM to 2 nM, with a detection limit of 2 pM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This new method showed an acceptable stability and reproducibility and was validated with OP-AChE spiked human plasma.

  2. Sensitive magnetic nanoparticle-based immunoassay of phosphorylated acetylcholinesterase using protein cage templated lead phosphate for signal amplification with graphite furnace atomic absorption spectrometry detection

    Science.gov (United States)

    Liang, Pei; Kang, Caiyan; Yang, Enjian; Ge, Xiaoxiao; Du, Dan; Lin, Yuehe

    2016-01-01

    We developed a new magnetic nanoparticles sandwich-like immunoassay using protein cage nanoparticles (PCN) for signal amplification together with graphite furnace atomic absorption spectrometry (GFAAS) for quantification of organophosphorylated acetylcholinesterase adduct (OP-AChE), the biomarker of exposure to organophosphate pesticides (OPs) and nerve agents. OP-AChE adducts were firstly captured by titanium dioxide coated magnetic nanoparticles (TiO2-MNPs) from the sample matrixes through metal chelation with phospho-moieties, and then selectively recognized by anti-AChE antibody labeled on PCN which was packed with lead phosphate in its cavity (PCN-anti-AChE). The sandwich-like immunoreaction was performed among TiO2-MNPs, OP-AChE and PCN-anti-AChE to form TiO2-MNPs/OP-AChE/PCN-anti-AChE immunocomplex. The complex could be easily isolated from the sample solution with the help of magnet, and the released lead ions from PCN were detected by GFAAS for the quantification of OP-AChE. Greatly enhanced sensitivity was achieved because PCN increased the amount of metal ions in the cavity of each apoferritin. The proposed immunoassay yielded a linear response over a broad OP-AChE concentrations from 0.01 nM to 2 nM, with a detection limit of 2 pM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This new method showed an acceptable stability and reproducibility and was validated with OP-AChE spiked human plasma. PMID:26953358

  3. Development and Integration of a Pulsed 2-micron Direct Detection Integrated Path Differential Absorption (IPDA) Lidar for CO2 Column Measurement from Airborne platform Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop, integrate and demonstrate a 2-micron pulsed Integrated Path Differential Absorption Lidar (IPDA) instrument CO2 Column Measurement from Airborne platform...

  4. Mass spectrometric imaging of flavonoid glycosides and biflavonoids in Ginkgo biloba L.

    Science.gov (United States)

    Beck, Sebastian; Stengel, Julia

    2016-10-01

    Ginkgo biloba L. is known to be rich in flavonoids and flavonoid glycosides. However, the distribution within specific plant organs (e.g. within leaves) is not known. By using HPLC-MS and MS/MS we have identified a number of previously known G. biloba flavonoid glycosides and biflavonoids from leaves. Namely, kaempferol, quercetin, isorhamnetin, myricetin, laricitrin/mearnsetin and apigenin glycosides were identified. Furthermore, biflavonoids like ginkgetin/isoginkgetin were also detected. The application of MALDI mass spectrometric imaging, enabled the compilation of concentration profiles of flavonoid glycosides and biflavonoids in G. biloba L. leaves. Both, flavonoid glycosides and biflavonoids show a distinct distribution in leaf thin sections of G. biloba L.

  5. Mass Spectrometric Calibration of Controlled Fluoroform Leak Rate Devices Technique and Uncertainty Analysis

    CERN Document Server

    Balsley, S D; Laduca, C A

    2003-01-01

    Controlled leak rate devices of fluoroform on the order of 10 sup - sup 8 atm centre dot cc sec sup - sup 1 at 25 C are used to calibrate QC-1 War Reserve neutron tube exhaust stations for leak detection sensitivity. Close-out calibration of these tritium-contaminated devices is provided by the Gas Dynamics and Mass Spectrometry Laboratory, Organization 14406, which is a tritium analytical facility. The mass spectrometric technique used for the measurement is discussed, as is the first principals calculation (pressure, volume, temperature and time). The uncertainty of the measurement is largely driven by contributing factors in the determination of P, V and T. The expanded uncertainty of the leak rate measurement is shown to be 4.42%, with a coverage factor of 3 (k=3).

  6. Liquid chromatography-mass spectrometric determination of rufinamide in low volume plasma samples.

    Science.gov (United States)

    Gáll, Zsolt; Vancea, Szende; Dogaru, Maria T; Szilágyi, Tibor

    2013-12-01

    Quantification of rufinamide in plasma was achieved using a selective and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method. The chromatographic separation was achieved on a reversed phase column (Zorbax SB-C18 100mm×3mm, 3.5μm) under isocratic conditions. The mobile phase consisted of a mixture of water containing 0.1% formic acid and methanol (50:50, v/v). The mass spectrometric detection of the analyte was in multiple reaction monitoring mode (MRM) using an electrospray positive ionization (ESI positive). The monitored ions were 127m/z derived from 239m/z rufinamide and 108m/z derived from 251m/z the internal standard (lacosamide). Protein precipitation with methanol was applied for sample preparation using only 50μl aliquots. The concentration range was 40-2000ng/ml for rufinamide in plasma. The limit of detection was 1.25ng/ml and the lower limit of quantification was established at 5ng/ml rufinamide concentration. Selectivity and matrix effect was verified using individual human, rat and rabbit plasma samples. Short-term, post-preparative and freeze-thaw stability was also investigated. The proposed method provides accuracy, precision and high-throughput (short runtime 4.5min) for quantitative determination of rufinamide in plasma. This is the first reported liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for analysis of rufinamide from low volume plasma samples. The LC-MS/MS method was validated according to the current official guidelines and can be applied to accurately measure rufinamide level of large number of plasma samples from clinical studies or therapeutic drug monitoring.

  7. Determination of trace elements in paints by direct sampling graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Bentlin, Fabrina R S; Pozebon, Dirce; Mello, Paola A; Flores, Erico M M

    2007-10-17

    A direct sampling graphite furnace atomic absorption spectrometric (DS-GFAAS) method for the determination of Cd, Pb, Cr, Ni, Co and Cu in paints has been developed. Serigraphy, acrylic and tattoo paints were analysed. Approaches like pyrolysis and atomization temperatures, modifiers and sample mass introduced in the atomizer were studied. Quantification was performed using calibration curves measured with aqueous standard solutions pipetted onto the platform. The sample mass introduced in the graphite tube ranged from 0.02 to 8.0 mg. Palladium was used as modifier for Cd, Pb and Cu, while Mg(NO3)2 was used for Co. For Ni determination, the graphite platform was covered with carbon powder. The characteristic masses of Cd, Pb, Cr, Ni, Co and Cu were 1.4, 22.5, 7.9, 11.0, 9.6 and 12.5 pg, while the limits of detection were 0.0004, 0.001, 0.03, 0.22, 0.11 and 0.05 microg g(-1) of Cd, Pb, Cr, Ni, Co and Cu, respectively. The accuracy was determined by comparison of the results with those obtained by inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS), using liquid sampling of digests. For matrix characterization, major and minor elements (Al, Mg, Ba, Ca, Cr, Cu, Pb, Sr, Ti and Mg) were determined by inductively coupled plasma optical emission spectrometry (ICP OES).

  8. Determination of trace elements in paints by direct sampling graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bentlin, Fabrina R.S. [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, UFRGS, 91501-970 Porto Alegre, RS (Brazil); Pozebon, Dirce [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, UFRGS, 91501-970 Porto Alegre, RS (Brazil)], E-mail: dircepoz@iq.ufrgs.br; Mello, Paola A.; Flores, Erico M.M. [Departamento de Quimica, Universidade Federal de Santa Maria, UFSM, 97105-900 Santa Maria, RS (Brazil)

    2007-10-17

    A direct sampling graphite furnace atomic absorption spectrometric (DS-GFAAS) method for the determination of Cd, Pb, Cr, Ni, Co and Cu in paints has been developed. Serigraphy, acrylic and tattoo paints were analysed. Approaches like pyrolysis and atomization temperatures, modifiers and sample mass introduced in the atomizer were studied. Quantification was performed using calibration curves measured with aqueous standard solutions pipetted onto the platform. The sample mass introduced in the graphite tube ranged from 0.02 to 8.0 mg. Palladium was used as modifier for Cd, Pb and Cu, while Mg(NO{sub 3}){sub 2} was used for Co. For Ni determination, the graphite platform was covered with carbon powder. The characteristic masses of Cd, Pb, Cr, Ni, Co and Cu were 1.4, 22.5, 7.9, 11.0, 9.6 and 12.5 pg, while the limits of detection were 0.0004, 0.001, 0.03, 0.22, 0.11 and 0.05 {mu}g g{sup -1} of Cd, Pb, Cr, Ni, Co and Cu, respectively. The accuracy was determined by comparison of the results with those obtained by inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS), using liquid sampling of digests. For matrix characterization, major and minor elements (Al, Mg, Ba, Ca, Cr, Cu, Pb, Sr, Ti and Mg) were determined by inductively coupled plasma optical emission spectrometry (ICP OES)

  9. High-Performance Liquid Chromatographic-Tandem Mass Spectrometric Determination of Itraconazole in Human Plasma for Bioavailability and Bioequivalence Studies

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Wook; Nam, Dae Young; Kang, Kyoung Hoon; Ha, Kyung Wook; Han, In Hee; Chang, Byung Kon; Yoon, Mi Kyeong; Lee, Jae Hwi [Chung-Ang University, Seoul (Korea, Republic of)

    2006-02-15

    A highly sensitive high-performance liquid chromatographic-tandem mass spectrometric method (HPLC-MSMS) has been developed to quantify itraconazole in human plasma for the purpose of pharmacokinetic studies. Sample preparation was carried out by liquid-liquid extraction using loratadine as an internal standard. Chromatographic separation used a YMC C{sub 18} column, giving an extremely fast total run time of 3 min. The method was validated and used for the bioequivalence study of itraconazole tablets in healthy male volunteers (n = 31). The lower limit of detection proved to be 0.2 ng /mL for itraconazole.

  10. Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: A feasible aviation safety measure to prevent potential encounters with volcanic plumes

    Science.gov (United States)

    Vogel, L.; Galle, B.; Kern, C.; Delgado, Granados H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lubcke, P.; Alvarez, Nieves J.M.; Cardenas, Gonzales L.; Platt, U.

    2011-01-01

    Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized 5 since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in 10 volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to vol- 15 canic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatepetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3◦) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to 25 the plume and SO2 was measured at all times well above the detection

  11. Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes

    Directory of Open Access Journals (Sweden)

    U. Platt

    2011-09-01

    Full Text Available Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2 or sulphuric acid (H2SO4 aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3° angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the

  12. Mass Spectrometric Analysis of Histone Proteoforms

    Science.gov (United States)

    Yuan, Zuo-Fei; Arnaudo, Anna M.; Garcia, Benjamin A.

    2014-06-01

    Histones play important roles in chromatin, in the forms of various posttranslational modifications (PTMs) and sequence variants, which are called histone proteoforms. Investigating modifications and variants is an ongoing challenge. Previous methods are based on antibodies, and because they usually detect only one modification at a time, they are not suitable for studying the various combinations of modifications on histones. Fortunately, mass spectrometry (MS) has emerged as a high-throughput technology for histone analysis and does not require prior knowledge about any modifications. From the data generated by mass spectrometers, both identification and quantification of modifications, as well as variants, can be obtained easily. On the basis of this information, the functions of histones in various cellular contexts can be revealed. Therefore, MS continues to play an important role in the study of histone proteoforms. In this review, we discuss the analysis strategies of MS, their applications on histones, and some key remaining challenges.

  13. Estimating intestinal absorption of inorganic and organic selenium compounds by in vitro flux and biotransformation studies in Caco-2 cells and ICP-MS detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Rasmussen, Laura Hyrup; Gabel-Jensen, Charlotte

    2012-01-01

    selenite and MeSeA fluxes correlated to poor in vivo absorption. Speciation analysis of cell lysate and donor and receptor solutions by LC-ICP-MS showed limited transformation of all selenium compounds. Extensive transformation as well as significantly increased absorptive flux was observed when co......SeA, including volatile species, whereas no significant increases in fluxes were observed. In summary, the absorption of selenite selenate and the selenoamino acids is considered complete under physiological conditions, but the absorption mechanisms and metabolism of the compounds are different. © 2011 Springer......The aim of the present work was to compare and estimate absorption and biotransformation of selected selenium compounds by studying their fluxes across Caco-2 cells. Five different selenium compounds, selenomethionine (SeMet), Se-methylselenocysteine (MeSeCys), selenate, selenite...

  14. Determination of Fe(II) and Fe(III) in small samples by microbore ion chromatography and photometric, atomic absorption spectrometry and total-reflection X-ray fluorescence detection

    Science.gov (United States)

    Sinner, T.; Hoffmann, P.; Ortner, H. M.

    1993-02-01

    Iron(II) and iron(III) are determined after separation on an ion Chromatographie column by various detection systems. "On-line" detection was achieved by the use of a photometer with a flow cell of 0.8 μl; for "off-line" detection, graphite furnace atomic absorption spectrometry or total-reflection X-ray fluorescence were used. The applicability of the methods is shown for standard solutions and atmospheric samples. As a typical result, 50 μg/l of iron can be determined in a 10 μl sample with a nucrobore ion chromatograph-photometer and atomic absorption system and 40 μg/l of iron in a microbore ion chromatograph-total-reflection X-ray fluorescence combination.

  15. Application of cloud point preconcentration and flame atomic absorption spectrometry for the determination of cadmium and zinc ions in urine, blood serum and water samples

    Directory of Open Access Journals (Sweden)

    Ardeshir Shokrollahi

    2013-01-01

    Full Text Available A simple, sensitive and selective cloud point extraction procedure is described for the preconcentration and atomic absorption spectrometric determination of Zn2+ and Cd2+ ions in water and biological samples, after complexation with 3,3',3",3'"-tetraindolyl (terephthaloyl dimethane (TTDM in basic medium, using Triton X-114 as nonionic surfactant. Detection limits of 3.0 and 2.0 µg L-1 and quantification limits 10.0 and 7.0 µg L-1were obtained for Zn2+ and Cd2+ ions, respectively. Relative standard deviation was 2.9 and 3.3, and enrichment factors 23.9 and 25.6, for Zn2+ and Cd2+ ions, respectively. The method enabled determination of low levels of Zn2+ and Cd2+ ions in urine, blood serum and water samples.

  16. Determination of tin, vanadium, iron, and molybdenum in various matrices by atomic absorption spectrometry using a simultaneous liquid-liquid extraction procedure.

    Science.gov (United States)

    Sánchez-Viñas, M; Bagur, G M; Gázquez, D; Camino, M; Romero, R

    1999-01-01

    An atomic-absorption spectrometric method is described for the determination of tin, vanadium, iron, and molybdenum in two certified reference materials, food samples, and petroleum crude. After treatment with acids, these elements are separated from matrix elements by simultaneous solvent extraction of 5,5'-methylenedisalicylohydroxamic acid complexes from HCl/NaClO4 solution into an isobutyl methyl ketone/tributyl phosphate solution. The detection limits range from 0.018 to 0.19 microg/mL (n = 3), and the relative standard deviations do not exceed 2.0% at levels of 0.5, 0.6, 2.0, and 7.0 microg/mL of Fe, Mo, V, and Sn, respectively. The method is selective and suffers only from interference by Zr(IV), Ti(IV), Th(IV), W(VI), PO4(3-), and F-.

  17. Metallomics approach to trace element analysis in ustilago maydis using cellular fractionation, atomic absorption spectrometry, and size exclusion chromatography with ICP-MS detection.

    Science.gov (United States)

    Muñoz, Alma Hortensia Serafin; Kubachka, Kevin; Wrobel, Kazimierz; Corona, Felix Gutierrez; Yathavakilla, Santha K V; Caruso, Joseph A; Wrobel, Katarzyna

    2005-06-29

    Huitlacoche is the ethnic name of the young fruiting bodies of Ustilago maydis, a common parasite of maize. In Mexico and other Latin American countries, this fungus has been traditionally appreciated as a local delicacy. In this work a metallomics approach was used with the determination of eight elements in huitlacoche by electrothermal atomic absorption spectrometry as one facet of this approach. The results obtained indicated relatively lower concentrations of commonly analyzed metals, as referred to the data reported for other mushroom types. This effect was ascribed to different accessibilities of elements, depending on fungus substrate (lower from plant than from soil). Subcellular fractionation was accomplished by centrifugation of cell homogenates suspended in Tris-HCl buffer. Recoveries of the fractionation procedure were in the range of 71-103%. For six elements (Cr, Cu, Fe, Mn, Ni, and Pb), the mean relative contributions in cytosol, cell walls, and mixed membrane fraction were 50.7, 48.2, and 1.1% respectively. To attain the molecular weight distribution of compounds containing target elements as an additional aspect of the metallomics approach, the fungus extract (1% sodium dodecyl sulfate in Tris-HCl, 30 mmol L(-)(1), pH 7.0) was analyzed by size exclusion chromatography with UV and ICP-MS detection. With spectrophotometric detection (280 nm), the elution of high molecular weight compounds was observed in the form of one peak (MW > 10 kDa), and several lower peaks appeared at higher retention times (MW < 10 kDa). On ICP-MS chromatograms, a coelution of (59)Co, (63)Cu, (57)Fe, (202)Hg, (60)Ni, and (80)Se with the first peak on the UV chromatogram was clearly observed, indicating that a fraction of each element incorporated with high molecular weight compounds (12.7, 19.8, 33.7, 100, 19.4, and 45.8%, respectively, based on the peak area measurements). From a comparison of (80)Se and (33)S chromatograms (for sulfur analysis, the extract was obtained in

  18. Mass spectrometric thermodynamic studies of oxide systems and materials

    Science.gov (United States)

    Stolyarova, V. L.

    2016-01-01

    Progress in methods of synthesis of advanced materials as well as utilization of such materials at high temperatures requires information on the vaporization processes and thermodynamic properties of oxide systems. The optimal experimental method for these purposes is high-temperature mass spectrometry. This review summarizes and classifies experimental results obtained in mass spectrometric studies of the high-temperature thermodynamic properties of oxide systems and materials carried out in the last two decades. Published data on the vaporization processes and thermodynamic properties of oxide materials for high-temperature technologies are discussed from the standpoint of acid-base concept and model approaches including statistical thermodynamic methods. The bibliography includes 248 references.

  19. E-2-benzylidenebenzocyclanones. II. IR and mass spectrometric investigations

    Science.gov (United States)

    Tarczay, Gy; Vékey, K.; Ludányi, K.; Perjési, P.; Sohár, P.

    2000-03-01

    A series of E-2-benzylideneindanones (a) -tetralones (b) and -benzosuberones (c) with OCH 3 ( 2- 4), NO 2 ( 5- 7) and F ( 8- 10) substituents in ortho, meta or para position was studied by IR and mass spectrometry. The most important IR bands were assigned and stated correlations between some frequencies and the stereostructure or conjugation feature of the molecules investigated. IR spectra were also analyzed in order to find frequencies characteristic of the size of the alkanone ring. The mass spectrometric investigation aimed at determining fragmentation pathways and finding correlations between them and the ring size of the alkanone ring or the position of the substituents.

  20. Liquid chromatography-mass spectrometric determination of losartan and its active metabolite on dried blood spots.

    Science.gov (United States)

    Rao, R Nageswara; Raju, S Satyanarayana; Vali, R Mastan; Sankar, G Girija

    2012-08-01

    A simple and rapid quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for simultaneous determination of losartan and its active metabolite, losartan carboxylic acid on rat dried blood spots was developed and validated as per regulatory guidelines. Losartan and its metabolite were extracted from dried blood spots using 50% aqueous methanol and separated on Waters XTerra(®) RP18 (250 mm × 4.6 mm, 5 μm) column using mobile phase composed of 40% acetonitrile and 60% aqueous ammonium acetate (10mM). The eluents were monitored using ESI tandem mass spectrometric detection with negative polarity in MRM mode using ion transitions m/z 421.2→179.0, m/z 435.3→157.0 and m/z 427.3→193.0 for losartan, losartan carboxylic acid and Irbesartan (internal standard), respectively. The method was validated over the linear range of 1-200 ng/mL and 5-1000 ng/mL with lower limits of quantification of 1.0 ng/mL and 5.0 ng/mL for losartan and losartan carboxylic acid, respectively. Inter and intra-day precision and accuracy (Bias) were below 5.96% and between -2.8 and 1.5%, respectively. The mean recoveries of the analytes from dried blood spots were between 89% and 97%. No significant carry over and matrix effects were observed. The stability of stock solution, whole blood, dried blood spot and processed samples were tested under different conditions and the results were found to be well within the acceptable limits. Additional validation parameters such as influence of hematocrit and spot volume were also evaluated and found to be well within the acceptable limits.

  1. A hybrid sorption - Spectrometric method for determination of synthetic anionic dyes in foodstuffs.

    Science.gov (United States)

    Tikhomirova, Tatyana I; Ramazanova, Gyulselem R; Apyari, Vladimir V

    2017-04-15

    A sorption-spectrometric method for determination of the anionic synthetic dyes based on their sorption on silica sorbent modified with hexadecyl groups (C16) followed by measuring the diffuse reflectance spectra on the surface of the sorbent has been proposed. Adsorption of sulfonated azo dyes Tartrazine (E102), Sunset Yellow FCF (E110), Ponceau 4R (E124) reaches maximum in acidic medium (1M HCl - pH 1). For the quinophthalone type dye Quinoline Yellow (E104), the adsorption is also maximal in an acidic medium (1M HCl - pH 2). The triphenylmethane dye Fast Green FCF (E143) is absorbed in the wider area of pH (1M HCl - pH 6). Increasing concentration of the dyes in a solution led to the increase in absorption band intensity in diffuse reflectance spectra of the adsorbent, which was used for their direct determination. The proposed method was applied to the determination of dyes in beverages and pharmaceuticals.

  2. MgII Absorption Lines in z=2.974 Damped Lyman-alpha System toward Gravitationally Lensed QSO APM 08279+5255 Detection of Small-scale Structure in MgII Absorbing Clouds

    CERN Document Server

    Kobayashi, N; Goto, M; Tokunaga, A; Kobayashi, Naoto; Terada, Hiroshi; Goto, Miwa; Tokunaga, Alan

    2002-01-01

    1.02-1.16 micron spectra (R ~ 7,000) of the gravitationally lensed QSO APM 08279+5255 at z_em=3.911 were obtained during the commissioning run of IRCS, the 1-5 micron near-infrared camera and spectrograph for the Subaru 8.2 m Telescope. Strong MgII doublet at 2976,2800 angstrom and FeII (2600 angstrom), FeII (2587 angstrom) absorption lines at z_abs=2.974 were clearly detected in the rest-frame UV spectra, confirming the presence of a damped Lyman-alpha system at the redshift as suggested by Petitjean et al. Also MgI (2853 angstrom) absorption line is probably detected. An analysis of the absorption lines including velocity decomposition was performed. This is a first detailed study of MgII absorption system at high redshift (z > 2.5) where the MgII doublet shifts into the near-infrared in the observer's frame. The spectra of the lensed QSO pair A and B with 0.38 arcsec separation were resolved in some exposure frames under excellent seeing condition. We extracted the MgII doublet spectra of A and B separatel...

  3. Photoinduced absorption of polyalkylthienylenevinylenes

    Energy Technology Data Exchange (ETDEWEB)

    Botta, C. (Ist. di Chimica delle Macromolecole (CNR), Milano (Italy)); Bradley, D.D.C. (Cambridge Univ. (United Kingdom). Cavendish Lab.); Friend, R.H. (Cambridge Univ. (United Kingdom). Cavendish Lab.); Musco, A. (Ist. di Scienze Chimiche, Univ. di Urbino (Italy))

    1993-03-15

    We present a photoinduced absorption study of alkyl substituted poly(2,5-thienylenevinylene)s. Three photoinduced states are detected in both the solid state and in solution. The two low-energy bands are assigned to bipolarons, while a third band peaked near the band edge has a different origin. In solution photoexcitated states are very long-lived and we propose that photoexcitation recombine via a solvent-assisted photo-doping mechanism. (orig.)

  4. Separation of seven arsenic compounds by high-performance liquid chromatography with on-line detection by hydrogen–argon flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, S. H.; Larsen, E. H.; Pritzl, G.

    1992-01-01

    Seven molecular forms of arsenic were separated by anion- and cation-exchange high-performance liquid chromatography (HPLC) with on-line detection by flame atomic absorption spectrometry (FAAS). The interfacing was established by a vented poly(tetrafluoroethylene) capillary tubing connecting...... the HPLC column to the nebulizer of the atomic absorption spectrometer. Arsenite, arsenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) were separated from each other and from the co-injected cationic arsenic compounds, arsenobetaine (AsB), arsenocholine (AsC) and the tetramethylarsonium ion (TMAs......-to-noise ratio of the on-line AAS detector was optimized. This involved the use of the hydrogen-argon-entrained air flame, a slotted tube atom trap in the flame for signal enhancement, electronic noise damping and a high-intensity light source. The detection limits in mu-g cm-3, using 100 mm3 injections...

  5. Separation of seven arsenic compounds by high performance liquid chromatography with on-line detection by hydrogen-argon flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, S. H.; Larsen, Erik Huusfeldt; Pritzl, G.

    1992-01-01

    Seven molecular forms of arsenic were separated by anion- and cation-exchange high-performance liquid chromatography (HPLC) with on-line detection by flame atomic absorption spectrometry (FAAS). The interfacing was established by a vented poly(tetrafluoroethylene) capillary tubing connecting...... the HPLC column to the nebulizer of the atomic absorption spectrometer. Arsenite, arsenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) were separated from each other and from the co-injected cationic arsenic compounds, arsenobetaine (AsB), arsenocholine (AsC) and the tetramethylarsonium ion (TMAs......-to-noise ratio of the on-line AAS detector was optimized. This involved the use of the hydrogen-argon-entrained air flame, a slotted tube atom trap in the flame for signal enhancement, electronic noise damping and a high-intensity light source. The detection limits in mu-g cm-3, using 100 mm3 injections...

  6. [Application of PCA to diesel engine oil spectrometric analysis].

    Science.gov (United States)

    Liu, Tao; Tian, Hong-Xiang; Guo, Wen-Yong

    2010-03-01

    In order to study wear characteristics of a 6-cylinder diesel engine, six different working statuses were arranged by altering the clearance between cylinder and piston. Sixty-nine oil samples were taken from engine at different loads under 6 working statuses and analyzed by Spectroil M Instrument made in US. Principal component analysis (PCA) was applied to analyzing spectrometric data of sixty-nine oil samples and clustering those data according to elements and oil samples separately based on the weighted coefficient and principal component scores. All 21 elements were used in element clustering and only 6 wear-related elements, namely iron, chromium, aluminum, copper, plumbum and silicon, were used in sample clustering. It is shown that PCA effectively clustered oil spectrometric data into three different principal components according to elements. The projection of two different principal components exhibited five types of elements combinations, namely wear elements (Fe, Cr, Cu, Al and Pb), high concentration additives elements (Na, Zn, P, Ca and Mg), low concentration additives elements (Ba and B), base constituent of lubricating oils (C and H) and interferential elements (Ni, Ti, Mo, V, Ag and Sn). Furthermore, PCA clearly clustered oil samples according to different clearance between cylinder and piston in the diesel engine. The study suggests that analyzing oil spectrographic data by PCA could find the sources of different elements, monitor engine conditions and diagnose wear faults.

  7. Study on water-dispersible colloids in saline-alkali soils by atomic force microscopy and spectrometric methods.

    Science.gov (United States)

    Liu, Zhiguo; Xu, Fengjie; Zu, Yuangang; Meng, Ronghua; Wang, Wenjie

    2016-06-01

    Recent studies have revealed that water-dispersible colloids play an important role in the transport of nutrients and contaminants in soils. In this study, water-dispersible colloids extracted from saline-alkali soils have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV absorption spectra. AFM observation indicated that the water-dispersible colloids contain some large plates and many small spherical particles. XRD, XPS, and UV absorption measurement revealed that the water-dispersible colloids are composed of kaolinite, illite, calcite, quartz and humic acid. In addition, UV absorption measurement demonstrated that the humic acids are associated with clay minerals. Water-dispersible colloids in the saline-alkali soils after hydrolyzed polymaleic anhydride treatment and an agricultural soil (nonsaline-alkali soil) were also investigated for comparison. The obtained results implied that the saline-alkali condition facilitates the formation of a large quantity of colloids. The use of AFM combined with spectrometric methods in the present study provides new knowledge on the colloid characteristics of saline-alkali soils. Microsc. Res. Tech. 79:525-531, 2016. © 2016 Wiley Periodicals, Inc.

  8. Ultratrace determination of tin by hydride generation in-atomizer trapping atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Průša, Libor [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Hlavova 8, Prague 2, CZ 128 43 Czech Republic (Czech Republic); Dědina, Jiří [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

    2013-12-04

    Graphical abstract: -- Highlights: •In-atomizer trapping HG-AAS was optimized for Sn. •A compact quartz trap-and-atomizer device was employed. •Generation, preconcentration and atomization steps were investigated in detail. •Hundred percent preconcentration efficiency for tin was reached. •Routine analytical method was developed for Sn determination (LOD of 0.03 ng mL{sup −1} Sn). -- Abstract: A quartz multiatomizer with its inlet arm modified to serve as a trap (trap-and-atomizer device) was employed to trap tin hydride and subsequently to volatilize collected analyte species with atomic absorption spectrometric detection. Generation, atomization and preconcentration conditions were optimized and analytical figures of merit of both on-line atomization as well as preconcentration modes were quantified. Preconcentration efficiency of 95 ± 5% was found. The detection limits reached were 0.029 and 0.14 ng mL{sup −1} Sn, respectively, for 120 s preconcentration period and on-line atomization mode without any preconcentration. The interference extent of other hydride forming elements (As, Se, Sb and Bi) on tin determination was found negligible in both modes of operation. The applicability of the developed preconcentration method was verified by Sn determination in a certified reference material as well as by analysis of real samples.

  9. The HI absorption 'Zoo'

    CERN Document Server

    Gereb, K; Morganti, R; Oosterloo, T A

    2014-01-01

    We present an analysis of the HI absorption in a sample of 101 flux-selected radio AGN (S_1.4 GHz > 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). HI absorption is detected in 32 galaxies, showing a broad variety of widths, shapes and kinematical properties. We characterize the HI spectra of the individual detections using the busy function (Westmeier et al. 2014). With the goal of identifying different morphological structures of HI, we study the kinematical and radio source properties of the detections as function of their width. Narrow lines (FWHM = 500 km/s). These detections are good candidates for being HI outflows. The detection rate of HI outflows is 5 percent in the total radio AGN sample. This fraction represents a lower limit, however it could suggests that, if outflows are a characteristic phenomenon of all radio sources, they would have a short depletion timescale compared to the lifetime of the AGN. Blueshifted and broad/asymmetric lines are more often present among young...

  10. Polarization-modulation infrared reflection-absorption spectroscopy affording time-resolved simultaneous detection of surface and liquid phase species at catalytic solid-liquid interfaces.

    Science.gov (United States)

    Meier, Daniel M; Urakawa, Atsushi; Baiker, Alfons

    2009-09-01

    Polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) combined with concentration modulation allows simultaneous monitoring of dynamic evolutions of surface and liquid phase species during reactions at catalytic interfaces as demonstrated for the Pt-catalysed oxidation of CO by O2 in cyclohexane.

  11. Spectrometric and Voltammetric Analysis of Urease – Nickel Nanoelectrode as an Electrochemical Sensor

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2007-07-01

    Full Text Available Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide andammonia. This enzyme is substrate-specific, which means that the enzyme catalyzes thehydrolysis of urea only. This feature is a basic diagnostic criterion used in thedetermination of many bacteria species. Most of the methods utilized for detection ofurease are based on analysis of its enzyme activity – the hydrolysis of urea. The aim of thiswork was to detect urease indirectly by spectrometric method and directly by voltammetricmethods. As spectrometric method we used is called indophenol assay. The sensitivity ofdetection itself is not sufficient to analyse the samples without pre-concentration steps.Therefore we utilized adsorptive transfer stripping technique coupled with differential pulse voltammetry to detect urease. The influence of accumulation time, pH of supporting electrolyte and concentration of urease on the enzyme peak height was investigated. Under the optimized experimental conditions (0.2 M acetate buffer pH 4.6 and accumulation time of 120 s the detection limit of urease evaluated as 3 S/N was 200 ng/ml. The activity of urease enzyme depends on the presence of nickel. Thus the influence of nickel(II ions on electrochemical response of the enzyme was studied. Based on the results obtained the interaction of nickel(II ions and urease can be determined using electrochemical methods. Therefore we prepared Ni nanoelectrodes to measure urease. The Ni nanoelectrodes was analysed after the template dissolution by scanning electron microscopy. The results shown vertically aligned Ni nanopillars almost covered the electrode surface, whereas the defect places are minor and insignificant in comparison with total electrode surface. We were able to not only detect urease itself but also to distinguish its native and denatured form.

  12. Advances in Mass Spectrometric Tools for Probing Neuropeptides

    Science.gov (United States)

    Buchberger, Amanda; Yu, Qing; Li, Lingjun

    2015-07-01

    Neuropeptides are important mediators in the functionality of the brain and other neurological organs. Because neuropeptides exist in a wide range of concentrations, appropriate characterization methods are needed to provide dynamic, chemical, and spatial information. Mass spectrometry and compatible tools have been a popular choice in analyzing neuropeptides. There have been several advances and challenges, both of which are the focus of this review. Discussions range from sample collection to bioinformatic tools, although avenues such as quantitation and imaging are included. Further development of the presented methods for neuropeptidomic mass spectrometric analysis is inevitable, which will lead to a further understanding of the complex interplay of neuropeptides and other signaling molecules in the nervous system.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tuzen, Mustafa [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Soylak, Mustafa [Department of Chemistry, Erciyes University, 38039 Kayseri (Turkey)], E-mail: soylak@erciyes.edu.tr; Citak, Demirhan [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Ferreira, Hadla S.; Korn, Maria G.A. [Universidade Federal da Bahia, Instituto de Quimica, 40170-290 Salvador (Brazil); Bezerra, Marcos A. [Universidade Estadual do Sudoeste da Bahia, 45200-190 Jequie (Brazil)

    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{sup -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 {mu}g L{sup -1}, respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 {mu}g L{sup -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.

  14. Acoustic absorption by sunspots

    Science.gov (United States)

    Braun, D. C.; Labonte, B. J.; Duvall, T. L., Jr.

    1987-01-01

    The paper presents the initial results of a series of observations designed to probe the nature of sunspots by detecting their influence on high-degree p-mode oscillations in the surrounding photosphere. The analysis decomposes the observed oscillations into radially propagating waves described by Hankel functions in a cylindrical coordinate system centered on the sunspot. From measurements of the differences in power between waves traveling outward and inward, it is demonstrated that sunspots appear to absorb as much as 50 percent of the incoming acoustic waves. It is found that for all three sunspots observed, the amount of absorption increases linearly with horizontal wavenumber. The effect is present in p-mode oscillations with wavelengths both significantly larger and smaller than the diameter of the sunspot umbrae. Actual absorption of acoustic energy of the magnitude observed may produce measurable decreases in the power and lifetimes of high-degree p-mode oscillations during periods of high solar activity.

  15. Measuring masses of large biomolecules and bioparticles using mass spectrometric techniques.

    Science.gov (United States)

    Peng, Wen-Ping; Chou, Szu-Wei; Patil, Avinash A

    2014-07-21

    Large biomolecules and bioparticles play a vital role in biology, chemistry, biomedical science and physics. Mass is a critical parameter for the characterization of large biomolecules and bioparticles. To achieve mass analysis, choosing a suitable ion source is the first step and the instruments for detecting ions, mass analyzers and detectors should also be considered. Abundant mass spectrometric techniques have been proposed to determine the masses of large biomolecules and bioparticles and these techniques can be divided into two categories. The first category measures the mass (or size) of intact particles, including single particle quadrupole ion trap mass spectrometry, cell mass spectrometry, charge detection mass spectrometry and differential mobility mass analysis; the second category aims to measure the mass and tandem mass of biomolecular ions, including quadrupole ion trap mass spectrometry, time-of-flight mass spectrometry, quadrupole orthogonal time-of-flight mass spectrometry and orbitrap mass spectrometry. Moreover, algorithms for the mass and stoichiometry assignment of electrospray mass spectra are developed to obtain accurate structure information and subunit combinations.

  16. Thermoluminescence (TL) spectra from quartz grains using on-line TL-spectrometric system

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, T.; Sugai, N.; Sakaue, H.; Shirai, N. [Niigata University, Niigata (Japan). Faculty of Science; Yasuda, K. [Daiwa Geological Laboratory Co. Ltd., Fukushima (Japan)

    1997-12-31

    An on-line spectrometric system installed with a small spectrometer and an image intensifier unit has been developed for weak and changeable TL-spectrum measurements with rising temperature for application to natural minerals. The detection sensitivity over visible wavelength regions was corrected using a known spectrum from a standard light source, and the detection sensitivity was also examined by a chemical luminol reaction. In an applied experiment, two quartz grain samples from two pyroclastic flows of the same origin, were subjected to testing with the present measuring system. The original data, consisting of 512 channels for every second at a constant heating rate of 1degC/s, were used to create a contour map or a 3-dimensional expression of TL-spectra after subtraction of background radiation. The artificially irradiated quartz grains clearly showed both red (RTL) and blue TL (BTL) in contrast to RTL alone from naturally accumulated TL. Both spectral expressions and glow curves from the same original data were found to be available to estimate quartz formation temperatures, together with thermoluminescence color images (TLCIs). 24 refs., 9 figs.

  17. Vapor generation – atomic spectrometric techniques. Expanding frontiers through specific-species preconcentration. A review

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Raúl A.; Pacheco, Pablo H.; Cerutti, Soledad [Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Instituto de Química de San Luis, INQUISAL, Centro Científico-Tecnológico de San Luis (CCT-San Luis), Consejo Nacional de Investigaciones Científicas y Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Martinez, Luis D., E-mail: ldm@unsl.edu.ar [Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Instituto de Química de San Luis, INQUISAL, Centro Científico-Tecnológico de San Luis (CCT-San Luis), Consejo Nacional de Investigaciones Científicas y Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina)

    2015-05-22

    This article reviews 120 articles found in SCOPUS and specific Journal cites corresponding to the terms ‘preconcentration’; ‘speciation’; ‘vapor generation techniques’ and ‘atomic spectrometry techniques’ in the last 5 years. - Highlights: • Recent advances in vapor generation and atomic spectrometry were reviewed. • Species-specific preconcentration strategies after and before VG were discussed. • New preconcentration and speciation analysis were evaluated within this framework. - Abstract: We review recent progress in preconcentration strategies associated to vapor generation techniques coupled to atomic spectrometric (VGT-AS) for specific chemical species detection. This discussion focuses on the central role of different preconcentration approaches, both before and after VG process. The former was based on the classical solid phase and liquid–liquid extraction procedures which, aided by automation and miniaturization strategies, have strengthened the role of VGT-AS in several research fields including environmental, clinical, and others. We then examine some of the new vapor trapping strategies (atom-trapping, hydride trapping, cryotrapping) that entail improvements in selectivity through interference elimination, but also they allow reaching ultra-low detection limits for a large number of chemical species generated in conventional VG systems, including complete separation of several species of the same element. This review covers more than 100 bibliographic references from 2009 up to date, found in SCOPUS database and in individual searches in specific journals. We finally conclude by giving some outlook on future directions of this field.

  18. Evaluation of affinity-based serum clean-up in mass spectrometric analysis: Plastic vs monoclonal antibodies.

    Science.gov (United States)

    Rossetti, Cecilia; Levernæs, Maren C S; Reubsaet, Léon; Halvorsen, Trine G

    2016-11-04

    Mass spectrometric assays are now of great relevance for trace compound analysis in complex matrices such as serum and plasma samples. Especially in the quantification of low abundant protein-biomarkers, the choice of the sample preparation is crucial. In the present paper immunocapture and Molecular Imprinted Polymers (MIPs) have been applied in the determination of pro-gastrin-releasing peptide, a Small Cell Lung Cancer marker. These affinity-based techniques were compared in terms of matrix effect, limits of detection, repeatability and extraction specificity. In addition, protein precipitation was included for comparison as it is a typical sample preparation method of biological matrices. The results highlighted differences in the methods' performance and specificity, strongly affecting the outcome of the mass spectrometric determination. Plastic and monoclonal antibodies confirmed to be sensitive and specific sample preparations able to determine ProGRP at clinical relevant concentration, although only the use of monoclonal antibodies allowed the reliable quantification of ProGRP at reference levels (8pM). In addition better insight in the specificity of the three sample preparation techniques was gained. This might also be of interest for other biological applications.

  19. A gas/liquid chromatographic-mass spectrometric method for the rapid screening of 250 pesticides in aqueous matrices

    Energy Technology Data Exchange (ETDEWEB)

    Chandramouli, B.; Harvan, D.; Brittain, S.; Hass, R. [Eno River Labs, LLC. Durham, NC (United States)

    2004-09-15

    Pesticide residues in food present a potentially serious and significant cause for concern. Many pesticides have been associated with significant health effects to the nervous and endocrine systems and some have been deemed carcinogenic. There are many well-established techniques for pesticide analysis. However, commercial pesticide methods have traditionally only been available for specific pesticide families, such as chlorinated pesticides or herbicides, and at detection limits ranging from 0.05 ppb to 1 ppm in aqueous matrices. Techniques that can quickly screen for the presence/absence of pesticide residues in food matrices are critical in ensuring the safety of food and water. This paper outlines a combined Gas Chromatographic-High Resolution Mass Spectrometric (GC-HRMS) and Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) screening assay for 250 pesticides that was developed for use in water, and soda samples at screening levels ranging from 0.1-5 ppb. The pesticides selected have been identified by the European Union as being of concern and the target of possible legislation. The list encompasses a variety of pesticide classes and compound groupings.

  20. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    Science.gov (United States)

    Campos, Reinaldo C.; Gonçalves, Rodrigo A.; Brandão, Geisamanda P.; Azevedo, Marlo S.; Oliveira, Fabiana; Wasserman, Julio

    2009-06-01

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C 18 column was used as stationary phase, and post column treatment was performed by UV irradiation (60 °C, 13 W). The eluate was then merged with 3 mol L - 1 HCl, reduction was performed by a NaBH 4 solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 µg L - 1 were obtained for ionic (Hg 2+) and HgCH 3+, for an injection volume of 200 µL. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sediments.

  1. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Reinaldo C. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil)], E-mail: rccampos@puc-rio.br; Goncalves, Rodrigo A.; Brandao, Geisamanda P.; Azevedo, Marlo S. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil); Oliveira, Fabiana; Wasserman, Julio [Institut of Geosciences, Fluminense Federal University, Av. Gal. Milton Tavares de Souza, s/n, 24.210-340, Niteroi, Rio de Janeiro (Brazil)

    2009-06-15

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C{sub 18} column was used as stationary phase, and post column treatment was performed by UV irradiation (60 deg. C, 13 W). The eluate was then merged with 3 mol L{sup -1} HCl, reduction was performed by a NaBH{sub 4} solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 {mu}g L{sup -1} were obtained for ionic (Hg{sup 2+}) and HgCH{sub 3}{sup +}, for an injection volume of 200 {mu}L. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sedi0011men.

  2. Trace species detection in the near infrared using Fourier transform broadband cavity enhanced absorption spectroscopy: initial studies on potential breath analytes.

    Science.gov (United States)

    Denzer, W; Hancock, G; Islam, M; Langley, C E; Peverall, R; Ritchie, G A D; Taylor, D

    2011-02-21

    Cavity enhanced absorption measurements have been made of several species that absorb light between 1.5 and 1.7 µm using both a supercontinuum source and superluminescent light emitting diodes. A system based upon an optical enhancement cavity of relatively high finesse, consisting of mirrors of reflectivity ∼99.98%, and a Fourier transform spectrometer, is demonstrated. Spectra are recorded of isoprene, butadiene, acetone and methane, highlighting problems with spectral interference and unambiguous concentration determinations. Initial results are presented of acetone within a breath-like matrix indicating ppm precision at absorption coefficient of ∼4 × 10(-9) cm(-1) reported within a 4 min acquisition time. Finally, two superluminescent light emitting diodes are coupled together to increase the wavelength coverage, and measurements are made simultaneously on acetylene, CO(2), and butadiene. The absorption cross-sections for acetone and isoprene have been measured with an instrumental resolution of 4 cm(-1) and are found to be 1.3 ± 0.1 × 10(-21) cm(2) at a wavelength of 1671.9 nm and 3.6 ± 0.2 × 10(-21) cm(2) at 1624.7 nm, respectively.

  3. Review of procedures involving separation and preconcentration for the determination of cadmium using spectrometric techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Sergio L.C. [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil)]. E-mail: slcf@ufba.br; Andrade, Jailson B. de [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil); Korn, Maria das Gracas A. [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil); Pereira, Madson de G. [Departamento de Ciencias Exatas e da Terra Campus 1-Cabula, Universidade do Estado da Bahia, Salvador, Bahia 41195-001 (Brazil); Lemos, Valfredo A. [Laboratorio de Quimica Analitica, Campus de Jequie, Universidade Estadual do Sudoeste da Bahia, Jequie, Bahia 45200-190 (Brazil); Santos, Walter N.L. dos [Departamento de Ciencias Exatas e da Terra Campus 1-Cabula, Universidade do Estado da Bahia, Salvador, Bahia 41195-001 (Brazil); Rodrigues, Frederico de Medeiros [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil); Empresa Baiana de Desenvolvimento Agricola S.A., Avenida Dorival Caymmi 15649, Itapoan, Salvador, Bahia 41635-150 (Brazil); Souza, Anderson S. [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil); Instituto Multidisciplinar em Saude, Campus AnisioTeixeira, Universidade Federal da Bahia, Vitoria da Conquista, Bahia 45055-090 (Brazil); Ferreira, Hadla S. [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil); Silva, Erik G.P. da [Instituto de Quimica, Campus Universitario Ondina, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil)

    2007-07-16

    Spectrometric techniques for the analysis of trace cadmium have developed rapidly due to the increasing need for accurate measurements at extremely low levels of this element in diverse matrices. This review covers separation and preconcentration procedures, such as electrochemical deposition, precipitation, coprecipitation, solid phase extraction, liquid-liquid extraction (LLE) and cloud point extraction (CPE), and consider the features of the their application with several spectrometric techniques.

  4. Determination of nickel in active pharmaceutical ingredients by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Bubnič, Zoran; Urleb, Uroš; Kreft, Katjuša; Veber, Marjan

    2010-03-01

    An electrothermal atomic absorption spectrometric procedure for the determination of nickel in active pharmaceutical ingredients was developed. Since the recoveries of nickel by the direct dissolution of samples in diluted nitric acid were low and caused errors in the determination of Ni in pharmaceutical samples, different approaches for sample pre-treatment were examined. It was found that the microwave digestion was the most suitable way for sample preparation. Various combinations of digestion agents and different microwave conditions were tested. The combination of nitric acid and hydrogen peroxide was found to be the most appropriate. The validity of the method was evaluated by recovery studies of spiked samples and by the comparison of the results obtained by inductively coupled plasma mass spectrometry (ICP-MS). The recovery ranged from 87.5 to 104.0% and a good agreement was achieved between both methods. The detection limit and the limit of quantification were 0.6 and 2.1 µg g-1 respectively. The precision of the method was confirmed by the determination of Ni in the spiked samples and was below 4%, expressed in terms of a relative standard deviation. The method was applied to the determination of nickel in production samples of active pharmaceutical ingredients and intermediates.

  5. Characterizations of the radioactive waste by the remotely-controlled collimated spectrometric system

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, Vyacheslav E.; Potapov, Victor N.; Smirnov, Sergey V.; Ivanov, Oleg P. [National Research Centre Kurchatov Institute, Moscow, (Russian Federation)

    2015-07-01

    Decontamination and decommissioning of the research reactors MR (Testing Reactor) and RFT (Reactor of Physics and Technology) has recently been initiated in the National Research Center (NRC) 'Kurchatov institute', Moscow. In the building, neighboring to the reactor, the storage of HLRW is located. The storage is made of monolithic concrete in which steel cells depth 4 m are located. In cells of storage the HLRW packed into cases are placed. These the radioactive waste are also subject to export on long storage in the specialized organization. For characterization of the radioactive waste in cases the remote-controlled collimated spectrometer system was used. The system consists of a spectrometric collimated gamma-ray detector, a color video camera and a control unit, mounted on a rotator, which are mounted on a tripod with the host computer. For determination of specific activity of radionuclides in cases, it is developed programs of calculation of coefficients of proportionality of specific activity to the corresponding speeds of the account in peaks of full absorption at single specific activity of radionuclides in cases. For determination of these coefficients the mathematical model of spectrometer system based on the Monte-Carlo method was used. Dependences of calibration coefficients for various radionuclides from distance between the detector and a case at various values of the radioactive waste density in cases are given. Measurements of specific activity in cases are taken and are discussed. By results of measurements decisions on the appeal of the radioactive waste being in cases are made. (authors)

  6. Mass Spectrometric Imaging of Red Fluorescent Protein in Breast Tumor Xenografts

    Science.gov (United States)

    Chughtai, Kamila; Jiang, Lu; Post, Harm; Winnard, Paul T.; Greenwood, Tiffany R.; Raman, Venu; Bhujwalla, Zaver M.; Heeren, Ron M. A.; Glunde, Kristine

    2013-05-01

    Mass spectrometric imaging (MSI) in combination with electrospray mass spectrometry (ESI-MS) is a powerful technique for visualization and identification of a variety of different biomolecules directly from thin tissue sections. As commonly used tools for molecular reporting, fluorescent proteins are molecular reporter tools that have enabled the elucidation of a multitude of biological pathways and processes. To combine these two approaches, we have performed targeted MS analysis and MALDI-MSI visualization of a tandem dimer (td)Tomato red fluorescent protein, which was expressed exclusively in the hypoxic regions of a breast tumor xenograft model. For the first time, a fluorescent protein has been visualized by both optical microscopy and MALDI-MSI. Visualization of tdTomato by MALDI-MSI directly from breast tumor tissue sections will allow us to simultaneously detect and subsequently identify novel molecules present in hypoxic regions of the tumor. MS and MALDI-MSI of fluorescent proteins, as exemplified in our study, is useful for studies in which the advantages of MS and MSI will benefit from the combination with molecular approaches that use fluorescent proteins as reporters.

  7. Detection of impaired intestinal absorption of long-chain fatty acids : validation studies of a novel test in a rat model of fat malabsorption

    NARCIS (Netherlands)

    Kalivianakis, M; Minich, DM; Havinga, R; Kuipers, F; Stellaard, F; Vonk, RJ; Verkade, HJ

    2000-01-01

    Background: Classic fat balance studies detect fat malabsorption but do not discriminate between the potential causes of malabsorption, such as impaired intestinal lipolysis or reduced uptake of fatty acids. Objective: We aimed to validate a novel test for the specific, sensitive detection of impair

  8. The HI absorption "Zoo"

    Science.gov (United States)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-03-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1) detections, which are associated with gas-rich mergers, we find three new cases of profiles with blueshifted broad wings (with FW20 ≳ 500 km s-1) in high radio power AGN. These detections are good candidates for being HI outflows. Together with the known cases of outflows already included in the sample (3C 293 and

  9. Gas chromatographic-mass spectrometric analysis of acrylamide and acetamide in cigarette mainstream smoke after on-column injection.

    Science.gov (United States)

    Diekmann, Joerg; Wittig, Arno; Stabbert, Regina

    2008-08-01

    A method is described for the simultaneous determination of two short-chained amides, acrylamide and acetamide (classified by the International Agency for Research on Cancer as probable and possible human carcinogens, respectively), in total particulate matter using gas chromatography-on-column injection and mass spectrometric detection. Sample preparation is kept to a minimum, and the proposed analytical procedure proves to be fast, sensitive, and precise. Validation studies show good linearity with a regression coefficient of r2=.000 for both compounds. Quantitation limits are 32 ng/mL for acrylamide and 70 ng/mL for acetamide. In the particulate phase of mainstream smoke from the University of Kentucky Reference Cigarette 2R4F, 2.3 microg/cig acrylamide and 4.7 microg/cig acetamide are found; no acetamide and only .0074 microg/cig acrylamide is found in the gas phase. Possible mechanisms of formation in cigarette smoke are discussed.

  10. Development of an Isotope-Dilution Liquid Chromatography/Mass Spectrometric Method for the Accurate Determination of Acetaminophen in Tablets

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyun Ju; Kim, Byung Joo; Lee, Joon Hee; Hwang, Eui Jin [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2010-12-15

    Acetaminophen (N-acetyl-p-aminophenol) is one of the most popular analgesic and antipyretic drugs. An isotope dilution mass spectrometric method based on LC/MS was developed as a candidate reference method for the accurate determination of acetaminophen in pharmaceutical product. After spiking an isotope labeled acetaminophen (acetyl-{sup 13}C{sub 2}, {sup 15}Nacetaminophen) as an internal standard, tablet extracts were analyzed by LC/MS in a selected reaction monitoring (SRM) mode to detect ions at m/z 152→110 and m/z 155→111 for acetaminophen and acetyl-{sup 13}C{sub 2}, {sup 15}N-acetaminophen, respectively. The repeatability and reproducibility of the developed ID/LC-MS method were tested for the validation and assessment of metrological quality of the method.

  11. Surface acoustic wave nebulization facilitating lipid mass spectrometric analysis.

    Science.gov (United States)

    Yoon, Sung Hwan; Huang, Yue; Edgar, J Scott; Ting, Ying S; Heron, Scott R; Kao, Yuchieh; Li, Yanyan; Masselon, Christophe D; Ernst, Robert K; Goodlett, David R

    2012-08-07

    Surface acoustic wave nebulization (SAWN) is a novel method to transfer nonvolatile analytes directly from the aqueous phase to the gas phase for mass spectrometric analysis. The lower ion energetics of SAWN and its planar nature make it appealing for analytically challenging lipid samples. This challenge is a result of their amphipathic nature, labile nature, and tendency to form aggregates, which readily precipitate clogging capillaries used for electrospray ionization (ESI). Here, we report the use of SAWN to characterize the complex glycolipid, lipid A, which serves as the membrane anchor component of lipopolysaccharide (LPS) and has a pronounced tendency to clog nano-ESI capillaries. We also show that unlike ESI SAWN is capable of ionizing labile phospholipids without fragmentation. Lastly, we compare the ease of use of SAWN to the more conventional infusion-based ESI methods and demonstrate the ability to generate higher order tandem mass spectral data of lipid A for automated structure assignment using our previously reported hierarchical tandem mass spectrometry (HiTMS) algorithm. The ease of generating SAWN-MS(n) data combined with HiTMS interpretation offers the potential for high throughput lipid A structure analysis.

  12. Comparison of pigment content of paint samples using spectrometric methods

    Science.gov (United States)

    Trzcińska, Beata; Kowalski, Rafał; Zięba-Palus, Janina

    2014-09-01

    The aim of the paper was to evaluate the influence of pigment concentration and its distribution in polymer binder on the possibility of colour identification and paint sample comparison. Two sets of paint samples: one containing red and another one green pigment were prepared. Each set consisted of 13 samples differing gradually in the concentration of pigment. To obtain the sets of various colour shades white paint was mixed with the appropriate pigment in the form of a concentrated suspension. After solvents evaporation the samples were examined using spectrometric methods. The resin and main filler were identified by IR method. Colour and white pigments were identified on the base of Raman spectra. Colour of samples were compared based on Vis spectrometry according to colour theory. It was found that samples are homogenous (parameter measuring colour similarity ΔE < 3). The values of ΔE between the neighbouring samples in the set revealed decreasing linear function and between the first and following one - a logarithmic function.

  13. Gamma Spectrometric Analysis of Iron Ore Samples of Arak, Iran

    Directory of Open Access Journals (Sweden)

    Reza Pourimani

    2016-09-01

    Full Text Available Introduction Iron ore is one of the most important natural raw materials that is widely used for manufacturing iron and steel. This type of ore contains various amounts of radionuclides; thus, exposing workers handling their extraction, transportation, and processing to radiation. Materials and Methods In this study, 12 ore samples (each mass weighing about 2 kg were collected from the iron ore mining areas of Arak region, Iran. The specific activities of 226Ra, 232Th, and 40K were determined usinggamma-ray spectrometry method employing high-purity germanium (HPGe detector. Results The specific activities of 226Ra, 232Th, and 40K in samples were 9.39-271.70 Bq/kg, -3 Sv/y suggested in International Commission of Radiological Protection (ICRP Publication 82. Conclusion The gamma ray spectrometric analysis showed that the specific activities of natural radionuclides in samples, except for limonite ore, were within the worldwide range. The effective dose received by workers was much lower than the maximum acceptable value (1000 μSv/y; therefore, the level of radiations in this mine had no adverse consequences for public health.

  14. Multisphere neutron spectrometric system with thermoluminescence dosemeters: sensitive improvement.

    Science.gov (United States)

    Gregori, B; Papadópulos, S; Cruzate, J; Kunst, J J

    2002-01-01

    In this work, a neutron spectrometric system based on a set of moderating spheres with thermoluminescence detectors (TLD) is presented. The system at the Nuclear Regulatory Authority (ARN) Dosimetry Laboratory consists of 12 solid spheres made of high-density polyethylene (p = 0.95 g x cm(-3)), with diameters ranging from 2" to 12" and TLD sensitive to thermal and gamma radiation, namely TLD-600 and TLD-700, located at the centre of the spheres. The neutron response matrix for this Bonner Sphere Spectrometer (BSS) was calculated using the MCNP-IVB code and the library ENDF/B-VI in the energy range between thermal neutrons and 100 MeV. The neutron spectrum was obtained using the LOUH182 unfolding code. The improvement in sensitivity of the system is based on the election of a different heating cycle of the TLD that allows an increase in sensitivity by a factor of 2.6 compared with the standard laboratory treatment. The system response for the calibration with an Am-Be source is presented.

  15. Asymmetry in ground and excited states in styryls and methoxystyryls detected by NMR (13C), absorption, fluorescence and fluorescence excitation spectroscopy

    Science.gov (United States)

    Stanova, A. V.; Ryabitsky, A. B.; Yashchuk, V. M.; Kachkovsky, O. D.; Gerasov, A. O.; Prostota, Ya. O.; Kropachev, O. V.

    2011-03-01

    Combined quantum-chemical and spectral study of electron structure features of styryls and their oxyanalogues containing benzothiazolium, benzooxazolium, indoleninium, pyridium, quinolinium residues has been fulfilled. It showed that asymmetry degree of molecular geometry and charge distribution in the chromophore of styryls and methoxystyryls considerably differ in the ground and excited states. It was established that two the lowest transitions in styryls are splitting and involve both donor levels, similarly to symmetrical cyanines. If compare with methoxystyryls the long-wave high intensive absorption band is shifted bathochromically due to considerable interaction between the donor quasi-local chromophores. In contrary, because of the low position of a lone electron pair of oxygen in methoxystyryls, only one donor quasi-local chromophore is effective, hence such unsymmetrical dyes absorb appreciably higher.

  16. Quantum-state resolved reaction dynamics at the gas-liquid interface: Direct absorption detection of HF(v,J) product from F(2P)+squalane

    Science.gov (United States)

    Zolot, Alexander M.; Harper, Warren W.; Perkins, Bradford G.; Dagdigian, Paul J.; Nesbitt, David J.

    2006-07-01

    Exothermic reactive scattering of F atoms at the gas-liquid interface of a liquid hydrocarbon (squalane) surface has been studied under single collision conditions by shot noise limited high-resolution infrared absorption on the nascent HF (v,J) product. The nascent HF (v,J) vibrational distributions are inverted, indicating insufficient time for complete vibrational energy transfer into the surface liquid. The HF (v=2,J) rotational distributions are well fit with a two temperature Boltzmann analysis, with a near room temperature component (TTD≈290K) and a second much hotter scattering component (THDS≈1040K). These data provide quantum state level support for microscopic branching in the atom abstraction dynamics corresponding to escape of nascent HF from the liquid surface on time scales both slow and fast with respect to rotational relaxation.

  17. Detection of chlorophylls in spores of seven ferns.

    Science.gov (United States)

    Tseng, Mei-Hwei; Lin, Kuei-Huei; Huang, Yi-Jia; Chang, Ya-Lan; Huang, Sheng-Cih; Kuo, Li-Yaung; Huang, Yao-Moan

    2017-03-01

    Fern spores were traditionally classified into chlorophyllous (green) and nonchlorophyllous (nongreen) types based on the color visible to the naked eye. Recently, a third type, "cryptochlorophyllous spores", is recognized, and these spores are nongreen under white light but contain chlorophylls. Epifluorescence microscopy was previously used to detect chlorophylls in cryptochlorophyllous spores. In addition to epifluorescence microscopy, current study performed some other approaches, including spore-squash epifluorescence, absorption spectra, laser-induced fluorescence emission spectra, thin layer chromatography (TLC), and ultra-high performance liquid chromatography with ultraviolet and mass spectrometric detection (UHPLC-UV-MS) in order to detect chlorophylls of spores of seven ferns (Sphaeropteris lepifera, Ceratopteris thalictroides, Leptochilus wrightii, Leptochilus pothifolius, Lepidomicrosorum buergerianum, Osmunda banksiifolia, and Platycerium grande). Destructive methods, such as TLC and UHPLC-UV-MS, successfully detected chlorophylls inside the spores when their signals of red fluorescence under epifluorescence microscope were masked by spore wall. Although UHPLC-UV-MS analysis was the most sensitive and reliable for determining the chlorophylls of spores, spore-squash epifluorescence is not only reliable but also cost- and time-effective one among our study methods. In addition, we first confirmed that Lepidomicrosorium buergerianum, Leptochilus pothifolius, Leptochilus wrightii, and Platycerium grande, produce cryptochlorophyllous spores.

  18. In situ direct sampling mass spectrometric study on formation of polycyclic aromatic hydrocarbons in toluene pyrolysis.

    Science.gov (United States)

    Shukla, Bikau; Susa, Akio; Miyoshi, Akira; Koshi, Mitsuo

    2007-08-30

    The gas-phase reaction products of toluene pyrolysis with and without acetylene addition produced in a flow tube reactor at pressures of 8.15-15.11 Torr and temperatures of 1136-1507 K with constant residence time (0.56 s) have been detected in an in situ direct sampling mass spectrometric study by using a vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry technique. Those products range from methyl radical to large polycyclic aromatic hydrocarbons (PAHs) of mass 522 amu (C(42)H(18)) including smaller species, radicals, polyynes, and PAHs, together with ethynyl, methyl, and phenyl PAHs. On the basis of observed mass spectra, the chemical kinetic mechanisms of the formation of products are discussed. Especially, acetylene is mixed with toluene to understand the effect of the hydrogen abstraction and acetylene addition (HACA) mechanism on the formation pathways of products in toluene pyrolysis. The most prominent outputs of this work are the direct detection of large PAHs and new reaction pathways for the formation of PAHs with the major role of cyclopenta-fused radicals. The basis of this new reaction route is the appearance of different sequences of mass spectra that well explain the major role of aromatic radicals mainly cyclopenta fused radicals of PAHs resulting from their corresponding methyl PAHs, with active participation of c-C(5)H(5), C(6)H(5), C(6)H(5)CH(2) ,and C(9)H(7) in the formation of large PAHs. The role of the HACA only seemed important for the formation of stable condensed PAHs from unstable primary PAHs with zigzag structure (having triple fusing sites) in one step by ring growth with two carbon atoms.

  19. Characterization of used lubricating oil by spectrometric techniques

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Andressa Moreira de, E-mail: andressa@ctaa.embrapa.br [Embrapa Agroindustria de Alimentos, Guaratiba, Rio de Janeiro, RJ (Brazil); Correa, Sergio Machado [Faculdade de Engenharia. Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil); Silva, Glauco Correa da [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Full text: The engine lubricating oil drags all kinds of impurities generated by wear of internal components. Thus, it is necessary to monitor the physical and chemical properties and concentration of metals in lubricants used to determine the appropriate time to replace them. Moreover, one can monitor the wear of the engines through the levels of metals in oils. To achieve these goals, some detection techniques such as Flame atomic absorption spectrometry (FAAS), Inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF), have been widely used to determine metals in lubricating oils and also in other oil derivatives. Thus, some of these techniques were used in this study. Also the technique used was Gas chromatography mass spectrometry (GC / MS) for characterization of chromatographic profile of the engine lubricating oil after use. Through the technique of ICP-OES for method of United States Environmental Protection Agency (USEPA) METHOD 6010B - Inductively coupled plasma optical emission spectrometry was performed to characterize metals in lubricating oil motor, using equipment from ICP-OES Perkin-Elmer{sup R} OPTIMA 3000 ICP-Winlab and software, obtaining the following identification of metals: barium (Ba), calcium (Ca), lead (Pb), copper (Cu), Chromium (Cr), iron (Fe), magnesium (Mg), molybdenum (Mo) and zinc (Zn). Using the XRF technique, through the equipment EDFRX Shimadzu{sup R} model 800HS EDX, Rh tube, applied voltage of 50kV, amperage 100{mu}A, detector Si (Li) cooled with liquid nitrogen and collimator 10mm, we analyzed all the components comprised in the range of Ti to U and Na to SC, identified the following metals: calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), molybdenum (Mo) and nickel (Ni). The characterization was performed by chromatographic methods: USEPA METHOD 5021A - Volatile organic compounds in various sample matrices using equilibrium headspace analysis, USEPA METHOD 8015B - Nonhalogenated Organics

  20. 2DB: a Proteomics database for storage, analysis, presentation, and retrieval of information from mass spectrometric experiments

    Directory of Open Access Journals (Sweden)

    Hippler Michael

    2008-07-01

    Full Text Available Abstract Background The amount of information stemming from proteomics experiments involving (multi dimensional separation techniques, mass spectrometric analysis, and computational analysis is ever-increasing. Data from such an experimental workflow needs to be captured, related and analyzed. Biological experiments within this scope produce heterogenic data ranging from pictures of one or two-dimensional protein maps and spectra recorded by tandem mass spectrometry to text-based identifications made by algorithms which analyze these spectra. Additionally, peptide and corresponding protein information needs to be displayed. Results In order to handle the large amount of data from computational processing of mass spectrometric experiments, automatic import scripts are available and the necessity for manual input to the database has been minimized. Information is in a generic format which abstracts from specific software tools typically used in such an experimental workflow. The software is therefore capable of storing and cross analysing results from many algorithms. A novel feature and a focus of this database is to facilitate protein identification by using peptides identified from mass spectrometry and link this information directly to respective protein maps. Additionally, our application employs spectral counting for quantitative presentation of the data. All information can be linked to hot spots on images to place the results into an experimental context. A summary of identified proteins, containing all relevant information per hot spot, is automatically generated, usually upon either a change in the underlying protein models or due to newly imported identifications. The supporting information for this report can be accessed in multiple ways using the user interface provided by the application. Conclusion We present a proteomics database which aims to greatly reduce evaluation time of results from mass spectrometric experiments and enhance

  1. 基于红外吸收光谱的瓦斯气体浓度检测技术%Detection Technology of Methane Gas Concentration Based on Infrared Absorption Spectrum

    Institute of Scientific and Technical Information of China (English)

    罗达峰; 杨建华; 仲崇贵

    2011-01-01

    According to the disadvantages of current methane sensor in coal mine, the infrared methane concentration detection system based on the principle of infrared spectrum absorption was designed using differential absorption technology. In the system single light beam absorbing cell and single light beam and double wavelengths technology are adopted. Differential amplifier circuit serves as the core of faint signal processing circuit that detects the output signal of methane concentration, and linear formula fits the curve of methane concentration and output voltage, which realizes accurate and full range detection of gas concentration. Experiment shows that measurement error is less than 2%, and the system has very high measurement precision and possesses the basis of industrial applications.%针对现有矿井瓦斯传感器的缺点,基于红外光谱吸收原理,采用差分吸收技术设计了红外瓦斯气体浓度探测系统.该系统采用单光路吸收气室和单光路双波长探测技术,利用差动放大电路为核心的微弱信号处理电路实现瓦斯浓度输出信号的检测,并采用线性关系式拟合瓦斯浓度和输出电压的关系曲线,实现了对瓦斯浓度的全量程精确探测.实验表明,该系统的测量误差小于2%,具有很高的测量精度,具备了煤矿应用的基础.

  2. XMM-Newton and UV Detection of OVIII and Broad HI absorption towards PKS 0558-504: a possible WHIM filament

    CERN Document Server

    Nicastro, F; Fields, D; Conciatore, M L; Zappacosta, L; Elvis, M; Mathur, S; Papadakis, I

    2009-01-01

    We present the first likely X-ray detection associated with Broad HI Ly$\\beta$ (BLB) and Ly$\\alpha$ (BLA) absorbers, consistent with being a WHIM filament. The absorber lies along the line of sight to the nearby ($z=0.1372$) Seyfert 1 galaxy PKS 0558-504. The X-ray absorber is marginally detected in two independent XMM-Newton spectra of PKS 0558-504, with a combined single line statistical significance of 2.8$\\sigma$ (2.7$\\sigma$ and 1.2$\\sigma$ in the two spectra, respectively). When fitted with our self-consistent hybrid-photoionization WHIM models, the combined XMM-{\\em Newton} spectrum is consistent with the presence of an OVIII K$\\alpha$ absorber at $z=(0.117 \\pm 0.001)$, with log$T=6.56_{-0.17}^{+0.19}$ K, and logN$_H=(21.5 \\pm 0.3) (Z/Z_{0.01\\odot})^{-1}$ cm$^{-2}$. The lack of detection of associated OVI in the archival FUSE spectrum of PKS 0558-504, allows us to infer a tighter lower limit on the temperature, of log$T>6.52$ K (at 1$\\sigma$). The statistical sigificance of this single X-ray detection ...

  3. Oxidative Ionization Under Certain Negative-Ion Mass Spectrometric Conditions

    Science.gov (United States)

    Hassan, Isra; Pavlov, Julius; Errabelli, Ramu; Attygalle, Athula B.

    2017-02-01

    1,4-Hydroquinone and several other phenolic compounds generate (M - 2) -• radical-anions, rather than deprotonated molecules, under certain negative-ion mass spectrometric conditions. In fact, spectra generated under helium-plasma ionization (HePI) conditions from 1,4-hydroquinone and 1,4-benzoquinone (by electron capture) were practically indistinguishable. Because this process involves a net loss of H• and H+, it can be termed oxidative ionization. The superoxide radical-anion (O2 -•), known to be present in many atmospheric-pressure plasma ion sources operated in the negative mode, plays a critical role in the oxidative ionization process. The presence of a small peak at m/z 142 in the spectrum of 1,4-hydroquinone, but not in that of 1,4-benzoquinone, indicated that the initial step in the oxidative ionization process is the formation of an O2 -• adduct. On the other hand, under bona fide electrospray ionization (ESI) conditions, 1,4-hydroquinone generates predominantly an (M - 1) - ion. It is known that at sufficiently high capillary voltages, corona discharges begin to occur even in an ESI source. At lower ESI capillary voltages, deprotonation predominates; as the capillary voltage is raised, the abundance of O2 -• present in the plasma increases, and the source in turn increasingly behaves as a composite ESI/APCI source. While maintaining post-ionization ion activation to a minimum (to prevent fragmentation), and monitoring the relative intensities of the m/z 109 (due to deprotonation) and 108 (oxidative ionization) peaks recorded from 1,4-hydroquinone, a semiquantitative estimation of the APCI contribution to the overall ion-generation process can be obtained.

  4. Determination of ultra trace amounts of bismuth in biological and water samples by electrothermal atomic absorption spectrometry (ET-AAS) after cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Shemirani, Farzaneh; Baghdadi, Majid; Ramezani, Majid; Jamali, Mohammad Reza

    2005-04-04

    A new approach for a cloud point extraction electrothermal atomic absorption spectrometric method was used for determining bismuth. The aqueous analyte was acidified with sulfuric acid (pH 3.0-3.5). Triton X-114 was added as a surfactant and dithizone was used as a complexing agent. After phase separation at 50 deg. C based on the cloud point separation of the mixture, the surfactant-rich phase was diluted using tetrahydrofuran (THF). Twenty microliters of the enriched solution and 10 {mu}l of 0.1% (w/v) Pd(NO{sub 3}){sub 2} as chemical modifier were dispersed into the graphite tube and the analyte determined by electrothermal atomic absorption spectrometry. After optimizing extraction conditions and instrumental parameters, a preconcentration factor of 196 was obtained for a sample of only 10 ml. The detection limit was 0.02 ng ml{sup -1} and the analytical curve was linear for the concentration range of 0.04-0.60 ng ml{sup -1}. Relative standard deviations were <5%. The method was successfully applied for the extraction and determination of bismuth in tap water and biological samples (urine and hair)

  5. Ground-based demonstration of a CO2 remote sensor using a 1.57μm differential laser absorption spectrometer with direct detection

    Science.gov (United States)

    Sakaizawa, Daisuke; Kawakami, Shuji; Nakajima, Masakatsu; Sawa, Yosuke; Matsueda, Hidekazu

    2010-10-01

    A 1.57-μm laser remote sensor using differential absorption spectrometry is being developed as a candidate for the next space-based mission to observe atmospheric CO2 and/or other trace gases. The performance of the newly-developed active remote sensor has been evaluated for horizontal measurements and initial vertical measurements have been demonstrated. This study shows the results of in-house and field measurements to evaluate column-averaged CO2 mixing ratios. The in-house measurements demonstrated the instrumental response showing agreement within a correlation coefficient of 0.998 for a known CO2 density. Field measurements to evaluate horizontal and vertical column-averaged CO2 mixing ratio were made with a measured precision of 0.49% and 1.7%, respectively. The horizontal integration range was 2.1 km and the vertical range extended from the surface up to the cloud base at ~3 km with corresponding accumulation time of 25 min. Complementary measurements with a multi-positioned in-situ sensor along the observation path demonstrated that the mean horizontal column-averaged CO2 density agreed within the difference of 2.8 ppm of the atmospheric CO2 density.

  6. Real-time bilinear rotation decoupling in absorptive mode J-spectroscopy: Detecting low-intensity metabolite peak close to high-intensity metabolite peak with convenience.

    Science.gov (United States)

    Verma, Ajay; Baishya, Bikash

    2016-05-01

    "Pure shift" NMR spectra display singlet peak per chemical site. Thus, high resolution is offered at the cost of valuable J-coupling information. In the present work, real-time BIRD (BIlinear Rotation Decoupling) is applied to the absorptive-mode 2D J-spectroscopy to provide pure shift spectrum in the direct dimension and J-coupling information in the indirect dimension. Quite often in metabolomics, proton NMR spectra from complex bio-fluids display tremendous signal overlap. Although conventional J-spectroscopy in principle overcomes this problem by separating the multiplet information from chemical shift information, however, only magnitude mode of the experiment is practical, sacrificing much of the potential high resolution that could be achieved. Few J-spectroscopy methods have been reported so far that produce high-resolution pure shift spectrum along with J-coupling information for crowded spectral regions. In the present work, high-quality J-resolved spectrum from important metabolomic mixture such as tissue extract from rat cortex is demonstrated. Many low-intensity metabolite peaks which are obscured by the broad dispersive tails from high-intensity metabolite peaks in regular magnitude mode J-spectrum can be clearly identified in real-time BIRD J-resolved spectrum. The general practice of removing such spectral overlap is tedious and time-consuming as it involves repeated sample preparation to change the pH of the tissue extract sample and subsequent spectra recording.

  7. Real-time bilinear rotation decoupling in absorptive mode J-spectroscopy: Detecting low-intensity metabolite peak close to high-intensity metabolite peak with convenience

    Science.gov (United States)

    Verma, Ajay; Baishya, Bikash

    2016-05-01

    "Pure shift" NMR spectra display singlet peak per chemical site. Thus, high resolution is offered at the cost of valuable J-coupling information. In the present work, real-time BIRD (BIlinear Rotation Decoupling) is applied to the absorptive-mode 2D J-spectroscopy to provide pure shift spectrum in the direct dimension and J-coupling information in the indirect dimension. Quite often in metabolomics, proton NMR spectra from complex bio-fluids display tremendous signal overlap. Although conventional J-spectroscopy in principle overcomes this problem by separating the multiplet information from chemical shift information, however, only magnitude mode of the experiment is practical, sacrificing much of the potential high resolution that could be achieved. Few J-spectroscopy methods have been reported so far that produce high-resolution pure shift spectrum along with J-coupling information for crowded spectral regions. In the present work, high-quality J-resolved spectrum from important metabolomic mixture such as tissue extract from rat cortex is demonstrated. Many low-intensity metabolite peaks which are obscured by the broad dispersive tails from high-intensity metabolite peaks in regular magnitude mode J-spectrum can be clearly identified in real-time BIRD J-resolved spectrum. The general practice of removing such spectral overlap is tedious and time-consuming as it involves repeated sample preparation to change the pH of the tissue extract sample and subsequent spectra recording.

  8. Rapid screening of phytosterols in orange juice by solid-phase microextraction on polyacrylate fibre derivatisation and gas chromatographic-mass spectrometric.

    Science.gov (United States)

    Balme, Sébastien; Gülaçar, Fazil O

    2012-05-01

    The potential of solid-phase microextraction on polyacrylate coated fibre, with sequential or simultaneous trimethylsilyl derivatisation followed by gas chromatographic-mass spectrometric analysis, was evaluated for a rapid determination of the distribution of the phytosterols in aqueous food matrixes. Influences of different parameters (bis(trimethylsilyl)trifluoro-acetamide and sterol exposure time, sterol concentration and experimental protocol) on the recovery of sterols were investigated to determine optimum conditions which were tested for sterol extraction and analysis from orange juice. Best selectivity, sterol recovery and derivatisation yields were obtained by extraction and simultaneous derivatisation through immersion of the SPME-PA fibre in the orange juice (10min, 65°C) after headspace absorption of BSTFA (30min, 65°C) on the fibre. Nevertheless the method developed cannot be used for quantitative analysis. But the possibility to effect rapid screen of phytosterol containing in complex media have been shown.

  9. Hydrogen--deuterium exchange in water vapor: the mass spectrometric sensitivities and the equilibrium constant

    Energy Technology Data Exchange (ETDEWEB)

    Pyper, J.W.; Dupzyk, R.J.; Friesen, R.D.; Bernasek, S.L.; May, C.A.; Echeverria, A.W.; Tolman, L.F.

    1976-04-21

    The equilibrium constant, K/sub HDO/, for the reaction H/sub 2/O + D/sub 2/O = 2HDO can be expressed as an intensity ratio, I, measured mass spectrometrically, times a sensitivity ratio, S, measured in mass spectrometric calibration experiments. The latter is difficult to measure and previously was assumed to be unity. The 2.4 percent discrepancy between K's from theoretical calculations and direct mass spectrometric measurements might be explained by another value of S. An indirect measurement of S using a pulsed-molecular beam quadrupole mass filter that has a unique three-chamber, three-leak gas inlet system is reported. The results show the sensitivities are probably equal and therefore S = 1. Systematic errors were found in the procedure, however, which precluded an unambiguous test of the theory.

  10. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    XIANG FuYuan; LIANG ShunLin; LI AiGen

    2009-01-01

    The diffuse interstellar bands (DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s, the exact nature of DIBs still remains unclear. This article reviews the history of the detec-tions of DIBs in the Milky Way and external galaxies, the major observational characteristics of DIBs, the correlations or anti-correlations among DIBs or between DIBs and other interstellar features (e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise), and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  11. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The diffuse interstellar bands(DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s,the exact nature of DIBs still remains unclear. This article reviews the history of the detections of DIBs in the Milky Way and external galaxies,the major observational characteristics of DIBs,the correlations or anti-correlations among DIBs or between DIBs and other interstellar features(e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise),and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  12. A cold metal poor cloud traced by a weak MgII absorption at z~0.45. First detection of SiI, CaI and FeI in a QSO absorber

    CERN Document Server

    D'Odorico, Valentina

    2007-01-01

    We present the observations of a weak MgII absorption system detected at z~0.452 in the UVES high resolution spectrum of the QSO HE0001-2340. The weakest of the two MgII components forming the system shows associated absorptions due to SiI, CaI and FeI observed for the first time in a QSO spectrum. We investigate the nature of this absorber by comparing its properties with those of different classes of absorbers (weak MgII, Damped Ly-alpha systems and local interstellar clouds) and reproducing its ionization conditions with photoionization models. The observed absorber belongs to the class of weak MgII systems on the basis of its equivalent width, however the relative strength of commonly observed transitions deviates significantly from those of the above mentioned absorbers. A rough estimate of the probability to cross such a system with a QSO line of sight is P~0.03. The presence of rare neutral transitions suggests that the cloud is shielded by a large amount of neutral Hydrogen. A detailed comparison of t...

  13. 火焰原子吸收光谱法检测不锈钢中铅含量应用分析%Application of Spectroscopy to Detect Lead Content in Stainless Steel Flame Atomic Absorption

    Institute of Scientific and Technical Information of China (English)

    柯桂沁

    2015-01-01

    The mixed acid dissolved stainless steel sample, using flame atomic stainless steel sample content of lead absorption spectroscopy, obtained experimentally determined effective lead content. Flame atomic absorption spectrometry method Lead stainless discussed, and takes effective measures to eliminate the background interference and matrix effects, the result of precise, can be applied to other aspects of lead content detection.%用混合酸溶解不锈钢样品后,使用火焰原子吸收光谱法测定不锈钢样品中铅的含量,得出了有效测定铅含量的实验方法。对火焰原子吸收法测定不锈钢中铅的方法进行分析讨论,并采取有效措施消除了背景干扰和基体效应,得出的结果精确,可以应用于其他方面的铅含量检测。

  14. Low-activity spectrometric gamma-ray logging technique for delineation of coal/rock interfaces in dry blast holes.

    Science.gov (United States)

    Asfahani, J; Borsaru, M

    2007-06-01

    A low-activity spectrometric gamma-ray logging technique is proposed in this paper as a sensitive tool for the delineation of coal/rock interfaces in dry blast holes. The advantages and superiority of this technique over traditional micro-density non-spectrometric gamma-ray tools are demonstrated.

  15. Development and validation of a liquid chromatographic-electrospray tandem mass spectrometric multiresidue method for anthelmintics in milk.

    Science.gov (United States)

    De Ruyck, Hendrik; Daeseleire, Els; De Ridder, Herman; Van Renterghem, Roland

    2002-11-08

    A liquid chromatographic-tandem mass spectrometric multiresidue method for the simultaneous quantitative determination of the tetrahydroimidazole, levamisole and the benzimidazoles thiabendazole, oxfendazole, oxibendazole, albendazole, fenbendazole, febantel and triclabendazole in milk has been developed and validated. The anthelmintic residues were extracted with ethyl acetate. The liquid chromatographic separation was performed on a reversed-phase C18 column with gradient elution. The analytes were detected by tandem quadrupole mass spectrometry after positive electrospray ionisation by multiple reaction monitoring. The confirmatory method is very sensitive and each component can be detected at a residue level lower than 1 microgram/l. The method is validated according to the revised European Union requirements and all parameters were found conform the criteria. The evaluated parameters were linearity, specificity, stability, recovery, precision (repeatability and within-laboratory reproducibility) and analytical limits (detection limit, decision limit and detection capability). This analytical method is applied in the Belgian monitoring programme for classical anthelmintic veterinary drugs in raw farm cow's milk.

  16. Me-BTABr reagent in cloud point extraction for spectrometric determination of copper in water samples

    OpenAIRE

    Lemos,Valfredo A; Santos, Juracir S.; Baliza,Patrícia X.

    2006-01-01

    A new preconcentration method using cloud point approach is proposed for copper determination. The reagent 2-[2´-(6-methyl-benzothiazolylazo)]-4-bromophenol (Me-BTABr) was used as a complexing agent and Triton X-114 was added as a surfactant. After phase separation, dilution of the surfactant-rich phase with acidified methanol was performed, and the copper content was measured by flame atomic absorption spectrometry. The proposed procedure allowed the determination of copper with detect...

  17. Determination of cadmium and lead in human biological samples by spectrometric techniques: a review.

    Science.gov (United States)

    Lemos, Valfredo Azevedo; de Carvalho, Anaildes Lago

    2010-12-01

    The analysis of human biological samples, such as blood, urine, nails, and hair, is generally used for the verification of human exposure to toxic metals. In this review, various spectrometric methods for the determination of cadmium and lead in biological samples are discussed and compared. Several spectrometric techniques are presented and discussed with respect to various characteristics such as sensitivity, selectivity, and cost. Special attention is drawn to the procedures for digestion prior to the determination of cadmium and lead in hair, nails, blood, and urine.

  18. Mass spectrometric analysis of electrophoretically separated allergens and proteases in grass pollen diffusates

    Directory of Open Access Journals (Sweden)

    Geczy Carolyn L

    2003-09-01

    Full Text Available Abstract Background Pollens are important triggers for allergic asthma and seasonal rhinitis, and proteases released by major allergenic pollens can injure airway epithelial cells in vitro. Disruption of mucosal epithelial integrity by proteases released by inhaled pollens could promote allergic sensitisation. Methods Pollen diffusates from Kentucky blue grass (Poa pratensis, rye grass (Lolium perenne and Bermuda grass (Cynodon dactylon were assessed for peptidase activity using a fluorogenic substrate, as well as by gelatin zymography. Following one- or two-dimensional gel electrophoresis, Coomassie-stained individual bands/spots were excised, subjected to tryptic digestion and analysed by mass spectrometry, either MALDI reflectron TOF or microcapillary liquid chromatography MS-MS. Database searches were used to identify allergens and other plant proteins in pollen diffusates. Results All pollen diffusates tested exhibited peptidase activity. Gelatin zymography revealed high Mr proteolytic activity at ~ 95,000 in all diffusates and additional proteolytic bands in rye and Bermuda grass diffusates, which appeared to be serine proteases on the basis of inhibition studies. A proteolytic band at Mr ~ 35,000 in Bermuda grass diffusate, which corresponded to an intense band detected by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense group 1 allergen Phl p 1, was identified by mass spectrometric analysis as the group 1 allergen Cyn d 1. Two-dimensional analysis similarly demonstrated proteolytic activity corresponding to protein spots identified as Cyn d 1. Conclusion One- and two-dimensional electrophoretic separation, combined with analysis by mass spectrometry, is useful for rapid determination of the identities of pollen proteins. A component of the proteolytic activity in Bermuda grass diffusate is likely to be related to the allergen Cyn d 1.

  19. Tunable Diode Laser Absorption Spectroscopy Sensor for Calibration Free Humidity Measurements in Pure Methane and Low CO2 Natural Gas.

    Science.gov (United States)

    Nwaboh, Javis Anyangwe; Pratzler, Sonja; Werhahn, Olav; Ebert, Volker

    2016-07-08

    We report a new direct tunable diode laser absorption spectroscopy (dTDLAS) sensor for absolute measurements of H2O in methane, ethane, propane, and low CO2 natural gas. The sensor is operated with a 2.7 µm DFB laser, equipped with a high pressure single pass gas cell, and used to measure H2O amount of substance fractions in the range of 0.31-25 000 µmol/mol. Operating total gas pressures are up to 5000 hPa. The sensor has been characterized, addressing the traceability of the spectrometric results to the SI and the evaluation of the combined uncertainty, following the guide to the expression of uncertainty in measurement (GUM). The relative reproducibility of H2O amount of substance fraction measurements at 87 µmol/mol is 0.26% (0.23 µmol/mol). The maximum precision of the sensor was determined using a H2O in methane mixture, and found to be 40 nmol/mol for a time resolution of 100 s. This corresponds to a normalized detection limit of 330 nmol mol(-1)·m Hz(-1/2) The relative combined uncertainty of H2O amount fraction measurements delivered by the sensor is 1.2%.

  20. 基于耦合技术的单色光谱吸收法检测甲烷气体浓度%Based on the Optical fiber coupling technology of spectral absorption method to detect methane gas concentration

    Institute of Scientific and Technical Information of China (English)

    姜建国; 刘盈萱; 王源

    2014-01-01

    In allusion to flammable and explosive safety problems of electronic testing equipment in methane gas concentration and adjustable laser expensive prices, put forward an application of coupling technique of mono-chromatic spectrum tests to detect methane gas concentration. The choice of monochromatic light source is given based on, designed a monochromatic spectrum absorption detection device based on optical fiber coupling technolo-gy. Application of Matlab is proposed for methane gas concentration and two sets of data output voltage linear fit-ting. Through the output voltage to predict methane gas concentration, and exam the error of the predicted values and the real value. The experimental results show that optical fiber coupling technology was applied to monochromatic spectrum absorption method to detect methane gas concentration can be without power in real-time detection of methane gas concentration, error less than 2%.%针对电子检测装置在甲烷气体浓度检测时存在易燃易爆等安全隐患,本文提出了一种基于光纤耦合技术的单色光谱吸收法检测甲烷气体浓度的方案。给出了单色光源的选择依据,设计了基于光纤耦合技术的单色光谱吸收法检测装置,提出了应用Matlab对甲烷气体浓度与输出电压两组数据进行线性拟合。通过输出电压预测出甲烷气体浓度,并检测了预测值与真实值的误差。实验结果表明,将光纤耦合技术应用于单色光谱吸收法检测甲烷气体浓度,可以在无电力介入的情况下对甲烷气体浓度进行实时检测,误差不超过2%。

  1. D-xylose absorption

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  2. Quantitative MALDI tandem mass spectrometric imaging of cocaine from brain tissue with a deuterated internal standard.

    NARCIS (Netherlands)

    Pirman, D.A.; Reich, R.F.; Kiss, A.; Heeren, R.M.A.; Yost, R.A.

    2013-01-01

    Mass spectrometric imaging (MSI) is an analytical technique used to determine the distribution of individual analytes within a given sample. A wide array of analytes and samples can be investigated by MSI, including drug distribution in rats, lipid analysis from brain tissue, protein differentiation

  3. Terverticillate Penicillia studied by direct electrospray mass spectrometric profiling of crude extracts: I. Chemosystematics

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn; Frisvad, Jens Christian

    1997-01-01

    A chemosystematic study of 339 isolates from all known terverticillate Penicillium taxa was performed using electrospray mass spectrometric analysis of extractable metabolites. The mass profiles were made by injecting crude plug extracts made from cultures grown on Czapek Yeast Autolysate agar (C...... to known secondary metabolites were, however, found in all mass profiles. (C) 1997 Elsevier Science Ltd....

  4. Gas Chromatographic Mass Spectrometric Determination of Myo-inositol in Humans Utilizing a Deuterated Internal Standard

    DEFF Research Database (Denmark)

    Andersen, Jan Rud; Larsen, Elfinn; Harbo, Helge;

    1982-01-01

    , was added as internal standard to the samples at an early stage in the analytical procedure. After separation and derivatization to the hexa-acetate, the gas chromatographic mass spectrometric analysis was carried out. A 25 m fused silica capillary column coated with methyl silicone was used, and the ions...

  5. 石墨炉原子吸收光谱法测定湘江水中铍%The Detection of Beryllium in Xiangjiang River by Graphite Furnace Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    汤根平

    2015-01-01

    采用石墨炉原子吸收光谱法测定湘江水中的铍,通过一系列的实验表明,该方法检测湘江水中铍的检测线性范围为0~2μg/L,加标回收率在95%~98%之间,精密度小于5%。检出限为0.00223μg/L,远远低于生活用水国家标准值0.002μg/L,结果表明石墨炉原子吸收光谱法可用于湘江水中铍的测定。%Graphite furnace atomic absorption spectrometry was applied to determine beryllium ion of Xiangjiang river.The experimental results showed that the detection linear range was 0~2 μg/L with adding standard recovery of 95%~98%and relative deviation less than 5%.The detection limit was 0.00223μg/L, which was much lower than the national standard limit of 0.002 mg/L for surface water.It was proved that the method can be used to determine beryllium ion in Xiangjiang river.

  6. Biosorption of platinum and palladium for their separation/preconcentration prior to graphite furnace atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Zylkiewicz, Beata E-mail: bgodlew@uwb.edu.pl

    2003-08-15

    Inexpensive baker's yeast Saccharomyces cerevisiae and green algae Chlorella vulgaris, either free or immobilized on silica gel have been shown to selectively accumulate platinum and palladium from water samples in acidic medium (pH 1.6-1.8). Optimization of conditions of metals biosorption (sample pH, algae and yeast masses, adsorption time, temperature) was performed in batch mode. The procedure of matrix separation based on biosorption of platinum and palladium on algae C. vulgaris covalently immobilized on silica gel in flow mode was developed. The use of algae in flow procedure offers several advantages compared with its use in the batch mode. The procedure shows better reproducibility (<2%), improved efficiency of platinum retention on the column (93.3{+-}1.6%), is less laborious and less time consuming. The best recovery of biosorbed metals from column (87.7{+-}3.3% for platinum and 96.8{+-}1.1 for palladium) was obtained with solution of 0.3 mol l{sup -1} thiourea in 1 mol l{sup -1} hydrochloric acid. The influence of thiourea on analytical signals of examined metals during GFAAS determination is discussed. The procedure has been applied for separation of noble metals from tap and waste water samples spiked with platinum and palladium.

  7. Development of a miniature dielectric barrier discharge–optical emission spectrometric system for bromide and bromate screening in environmental water samples

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yong-Liang [Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang 110819 (China); Research Center for Analytical Sciences, College of Sciences, Northeastern University, Box 332, Shenyang 110819 (China); Cai, Yi [Research Center for Analytical Sciences, College of Sciences, Northeastern University, Box 332, Shenyang 110819 (China); Chen, Ming-Li, E-mail: chenml@mail.neu.edu.cn [Research Center for Analytical Sciences, College of Sciences, Northeastern University, Box 332, Shenyang 110819 (China); Wang, Jian-Hua, E-mail: jianhuajrz@mail.neu.edu.cn [Research Center for Analytical Sciences, College of Sciences, Northeastern University, Box 332, Shenyang 110819 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071 (China)

    2014-01-27

    Graphical abstract: -- Highlights: •Dielectric barrier discharge (DBD) is for the first time used as a radiation source for the excitation of bromine and its emission. •A DBD–optical emission spectrometric (OES) system was developed for the detection of bromide and bromate. •The DBD–OES system has been demonstrated by screening trace bromide and bromate in a series of environmental water samples. -- Abstract: Dielectric barrier discharge (DBD) at atmospheric pressure provides an efficient radiation source for the excitation of bromine and it is used for the first time for optical emission spectrometric (OES) detection of bromide and bromate. A portable DBD–OES system is developed for screening potential pollution from bromide and bromate in environmental waters. Bromide is on-line oxidized to bromine for in-situ generation of volatile bromine. Meanwhile, a helium stream carries bromine into the DBD micro-plasma for its excitation at a discharging voltage of 3.7 kV and optical emission spectrometric detection with a QE65000 charge-coupled device (CCD) spectrometer in the near-infrared spectral region. Similarly, the quantification of bromate is performed by its pre-reduction into bromide and then oxidized to bromine. The spectral characteristics and configuration of the DBD micro-plasma excitation source in addition to the oxidation vapor generation of bromine have been thoroughly investigated. With a sampling volume of 1 mL, a linear range of 0.05–10.0 mg L{sup −1} is obtained with a detection limit of 0.014 mg L{sup −1} by measuring the emission at 827 nm. A precision of 2.3% is achieved at 3 mg L{sup −1} bromide. The system is validated by bromine detection in certified reference material of laver (GBW10023) at mg L{sup −1} level, giving rise to satisfactory agreement. In addition, it is further demonstrated by screening trace bromide and bromate as well as spiking recoveries in a series of environmental water samples.

  8. Study on Experiment of Absorption Spectroscopy Detection of Pesticide Residues of Carbendazim in Orange Juice%橙汁中多菌灵农药残留吸收光谱特征研究

    Institute of Scientific and Technical Information of China (English)

    季仁东; 陈梦岚; 赵志敏; 朱星玥; 王乐新; 刘全金

    2014-01-01

    coefficient was 0 .996 ,and the recovery was :81% ~102% .According to the regression model ,we can ob-tain the amount of carbendazim pesticide residues in orange juice .It was verified that the method of using ultraviolet-visible ab-sorption spectra was feasible to detect the carbendazim residues in orange juice .The result proved that it is possible to detect pesticide residues of carbendazim in orange juice ,and it can meet the needs of rapid analysis .This study provides a new way for the detection of pesticide residues .

  9. Oxygen Absorption in Cooling Flows.

    Science.gov (United States)

    Buote

    2000-04-01

    The inhomogeneous cooling flow scenario predicts the existence of large quantities of gas in massive elliptical galaxies, groups, and clusters that have cooled and dropped out of the flow. Using spatially resolved, deprojected X-ray spectra from the ROSAT PSPC, we have detected strong absorption over energies approximately 0.4-0.8 keV intrinsic to the central approximately 1&arcmin; of the galaxy NGC 1399, the group NGC 5044, and the cluster A1795. These systems have among the largest nearby cooling flows in their respective classes and low Galactic columns. Since no excess absorption is indicated for energies below approximately 0.4 keV, the most reasonable model for the absorber is warm, collisionally ionized gas with T=105-106 K in which ionized states of oxygen provide most of the absorption. Attributing the absorption only to ionized gas reconciles the large columns of cold H and He inferred from Einstein and ASCA with the lack of such columns inferred from ROSAT and also is consistent with the negligible atomic and molecular H inferred from H i and CO observations of cooling flows. The prediction of warm ionized gas as the product of mass dropout in these and other cooling flows can be verified by Chandra and X-Ray Multimirror Mission.

  10. Distribution of coniferin in differentiating normal and compression woods using MALDI mass spectrometric imaging coupled with osmium tetroxide vapor treatment.

    Science.gov (United States)

    Yoshinaga, Arata; Kamitakahara, Hiroshi; Takabe, Keiji

    2016-05-01

    Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) was employed to detect monolignol glucosides in differentiating normal and compression woods of two Japanese softwoods, Chamaecyparis obtusa and Cryptomeria japonica Comparison of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry collision-induced dissociation fragmentation analysis and structural time-of-flight (MALDI-TOF CID-FAST) spectra between coniferin and differentiating xylem also confirmed the presence of coniferin in differentiating xylem. However, as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and MALDI-TOF CID-FAST spectra of sucrose were similar to those of coniferin, it was difficult to distinguish the distribution of coniferin and sucrose using MALDI-MSI and collision-induced dissociation measurement only. To solve this problem, osmium tetroxide vapor was applied to sections of differentiating xylem. This vapor treatment caused peak shifts corresponding to the introduction of two hydroxyl groups to the C=C double bond in coniferin. The treatment did not cause a peak shift for sucrose, and therefore was effective in distinguishing coniferin and sucrose. Thus, it was found that MALDI-MSI combined with osmium tetroxide vapor treatment is a useful method to detect coniferin in differentiating xylem.

  11. Absorption of light dark matter in semiconductors

    CERN Document Server

    Hochberg, Yonit; Zurek, Kathryn M

    2016-01-01

    Semiconductors are by now well-established targets for direct detection of MeV to GeV dark matter via scattering off electrons. We show that semiconductor targets can also detect significantly lighter dark matter via an absorption process. When the dark matter mass is above the band gap of the semiconductor (around an eV), absorption proceeds by excitation of an electron into the conduction band. Below the band gap, multi-phonon excitations enable absorption of dark matter in the 0.01 eV to eV mass range. Energetic dark matter particles emitted from the sun can also be probed for masses below an eV. We show that the reach for absorption of a relic kinetically mixed dark photon or pseudoscalar in semiconductors such as germanium or silicon can exceed current astrophysical and terrestrial constraints, with only a moderate exposure.

  12. Determination of copper in powdered chocolate samples by slurry-sampling flame atomic-absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Walter N.L. dos; Silva, Erik G.P. da; Fernandes, Marcelo S.; Araujo, Rennan G.O.; Costa, Anto' ' enio C.S.; Ferreira, Sergio L.C. [Nucleo de Excelencia em Quimica Analitica da Bahia, Universidade Federal da Bahia, Instituto de Quimica, Salvador, Bahia (Brazil); Vale, M.G.R. [Instituto de Quimica, Universidade Federal da Bahia do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul (Brazil)

    2005-06-01

    Chocolate is a complex sample with a high content of organic compounds and its analysis generally involves digestion procedures that might include the risk of losses and/or contamination. The determination of copper in chocolate is important because copper compounds are extensively used as fungicides in the farming of cocoa. In this paper, a slurry-sampling flame atomic-absorption spectrometric method is proposed for determination of copper in powdered chocolate samples. Optimization was carried out using univariate methodology involving the variables nature and concentration of the acid solution for slurry preparation, sonication time, and sample mass. The recommended conditions include a sample mass of 0.2 g, 2.0 mol L{sup -1} hydrochloric acid solution, and a sonication time of 15 min. The calibration curve was prepared using aqueous copper standards in 2.0 mol L{sup -1} hydrochloric acid. This method allowed determination of copper in chocolate with a detection limit of 0.4 {mu}g g{sup -1} and precision, expressed as relative standard deviation (RSD), of 2.5% (n=10) for a copper content of approximately 30 {mu}g g{sup -1}, using a chocolate mass of 0.2 g. The accuracy was confirmed by analyzing the certified reference materials NIST SRM 1568a rice flour and NIES CRM 10-b rice flour. The proposed method was used for determination of copper in three powdered chocolate samples, the copper content of which varied between 26.6 and 31.5 {mu}g g{sup -1}. The results showed no significant differences with those obtained after complete digestion, using a t-test for comparison. (orig.)

  13. Structure of Liquid Aluminum and Hydrogen Absorption

    Institute of Scientific and Technical Information of China (English)

    LIU Yang; DAI Yongbing; WANG Jun; SHU Da; SUN Baode

    2011-01-01

    The hydrogen content in aluminum melts at different temperature was detected. The structure in aluminum melts was investigated by molecular dynamics simulation. The first peak position of pair correlation function, atomic coordination number and viscosity of aluminum melts were calculated and they changed abnormally in the same temperature range. The mechanism of hydrogen absorption has been discussed. From molecular dynamics calculations, the interdependence between melt structural properties and hydrogen absorption were obtained.

  14. MASERATI: a new rocket-borne diode laser absorption spectrometer for in-situ measurement of trace gases in the middle and upper atmosphere; MASERATI: Ein neues raketengetragenes Diodenlaser-Absorptionsspektrometer zur in situ-Messung von Spurengasen in der mittleren und oberen Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Lucke, H. von

    1999-09-01

    MASERATI (middle atmosphere spectrometric experiment on Rockets for the analysis of trace gas influences) is the first rocket-borne tunable diode laser absorption spectrometer (TDLAS). It was developed to measure water vapor and carbon dioxide in the altitude range from 50 to 90 km and 120 km, respectively. Infrared absorption spectroscopy using two laser diodes is applied to measure both trace gases simultaneously. The laser beams are sent into an open multiple-pass absorption setup mounted on top of the sounding rocket. High sensitivity is achieved by means of frequency modulation and lock-in techniques. The results of several tests performed in the laboratory demonstrate that the instrument is capable of detecting relative absorbances down to 10{sup -4} - 10{sup -5} when integrating spectra for 1 s. Two almost identical MASERATI instruments have been built and launched on sounding rockets from the Andoeya rocket range (69 N, 16 E) in northern Norway during winter 1997/98. The results of these flights demonstrate that MASERATI is a new suitable tool for in situ studies of the mesosphere and lower thermosphere. (orig.)

  15. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium metal

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium metal to determine compliance with specifications.

  16. Absorption, luminescence, and scattering of single nano-objects

    NARCIS (Netherlands)

    Yorulmaz, Mustafa

    2013-01-01

    We study the technique of photothermal microscopy by which we can detect single nano-objects by their absorption at room temperature. We optimize the sensitivity of this technique and demonstrate the first optical detection of a single molecule by its absorption at room temperature. Moreover, we com

  17. Detection of the magnetic and electric transitions by electron paramagnetic resonance and low-field microwave absorption in the magnetoelectric Pb(Fe{sub 0.5}Ta{sub 0.5})O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G., E-mail: memodin@yahoo.co [Departamento de Fisica, ESFM-IPN, U.P. Adolfo Lopez Mateos Edificio 9, Av. Instituto Politecnico Nacional S/N, San Pedro Zacatenco, Mexico DF 07738 (Mexico); Montiel, H. [Departamento de Tecnociencias, Centro de Ciencias Aplicadas y Desarrollo Tecnologico de la Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Mexico DF 04510 (Mexico); Pena, J.A.; Castellanos, M.A. [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Mexico DF 04510 (Mexico); Zamorano, R. [Departamento de Fisica, ESFM-IPN, U.P. Adolfo Lopez Mateos Edificio 9, Av. Instituto Politecnico Nacional S/N, San Pedro Zacatenco, Mexico DF 07738 (Mexico)

    2010-10-22

    Graphical abstract: Display Omitted Research highlights: {yields} LFMA spectra showed straight lines with positive slope and non-hysteretic traces. {yields} The spectral changes for the plot of the slope vs. temperature give evidence of magnetic and electric orderings, with a very high detection sensibility. - Abstract: An electron paramagnetic resonance (EPR) study of Pb(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} powder samples in perovskite-type structure at X-band (8.8-9.8 GHz), in the 120-300 K temperature range, is presented. For all the temperatures, the EPR spectra show a single broad line attributable to Fe{sup 3+} ions. The onset of the ferro-paraelectric and antiferro-paramagnetic transitions has been determined from the temperature dependence of parameters deduced from the EPR spectra: the peak-to-peak linewidth ({Delta}H{sub pp}), the resonance field (H{sub res}) and the integrated intensity (I{sub EPR}). Low-field microwave absorption (LFMA) is used to give further knowledge on this material; where this technique also gives evidence of the magnetic and electric orders.

  18. OPAD data analysis. [Optical Plumes Anomaly Detection

    Science.gov (United States)

    Buntine, Wray L.; Kraft, Richard; Whitaker, Kevin; Cooper, Anita E.; Powers, W. T.; Wallace, Tim L.

    1993-01-01

    Data obtained in the framework of an Optical Plume Anomaly Detection (OPAD) program intended to create a rocket engine health monitor based on spectrometric detections of anomalous atomic and molecular species in the exhaust plume are analyzed. The major results include techniques for handling data noise, methods for registration of spectra to wavelength, and a simple automatic process for estimating the metallic component of a spectrum.

  19. Nutrition and magnesium absorption.

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true magnesium abs

  20. Bioacoustic Absorption Spectroscopy

    Science.gov (United States)

    2016-06-07

    frequencies (Ching and Weston, 1971). RESULTS Measured resonance frequencies of absorption lines, which were attributed to adult (~ 1.3 khz) and juvenile ...of adult and juvenile sardines. These results suggest that bioacoustic absorption spectroscopy measurements permit isolation of juvenile from adult...from broadband tomographic transmission loss measurements over large areas . 2. Depths of sardines and contours of phytoplankton concentrations vs. time

  1. Electrochemical oxidation and cleavage of peptides analyzed with on-line mass spectrometric detection

    NARCIS (Netherlands)

    Permentier, H.P.; Jurva, U; Barroso, B.; Bruins, A.P.

    2003-01-01

    An on-line electrochernistry/electrospray mass spectrometry system (EC/MS) is described that allows fast analysis of the oxidation products of peptides. A range of peptides was oxidized in an electrochemical cell by application of a potential ramp from 0 to 1.5 V during passage of the sample. Electr

  2. Elemental speciation analysis by multicapillary gas chromatography with microwave-induced plasma atomic spectrometric detection.

    Science.gov (United States)

    Rodriguez Pereiro, I; Schmitt, V O; Lobiński, R

    1997-12-01

    Multicapillary column gas chromatography (MC-GC)/microwave-induced plasma atomic emission spectrometry (MIP AES) was developed for fast speciation analysis of organotin compounds in the environment. Ethylated butyltin compounds could be separated isothermally within less than 30 s (instead of ∼5-10 min) without sacrificing either the resolution or the sample capacity of conventional capillary GC with oven temperature gradient programming. Careful optimization of the pressure and temperature GC program allowed a comprehensive organotin speciation analysis including phenyltin compounds within less than 2.5 min, increasing the sample throughput 6-fold. Compatibility of MC-GC with an MIP atomic emission detector (MIP-AED) was discussed. MC-GC/MIP-AES was validated for the analysis of sediment (PACS-1 and BCR 462) and biological (NIES11) certified reference materials.

  3. Photochemical vapor generation of lead for inductively coupled plasma mass spectrometric detection

    Science.gov (United States)

    Duan, Hualing; Zhang, Ningning; Gong, Zhenbin; Li, Weifeng; Hang, Wei

    2016-06-01

    Photochemical vapor generation (PCVG) of lead was successfully achieved with a simplified and convenient system, in which only low molecular weight organic acid and a high-efficiency photochemical reactor were needed. The reactor was used to generate lead volatile species when a solution of lead containing a small amount of low molecular weight organic acid was pumped through. Several factors, including the concentration of acetic acid, the concentration of hydrochloride acid, and the irradiation time of UV light were optimized. Under the optimal conditions, including the addition of 0.90% (v/v) acetic acid and 0.03% (v/v) hydrochloride acid, and irradiation time of 28 s, intense and repeatable signal of lead volatile species was successfully obtained and identified with inductively coupled plasma mass spectrometry (ICPMS). In addition, the effects from inorganic anions and transition metal ions, including Cl-, NO3-, SO42 -, Cu2 +, Fe3 +, Co2 + and Ni2 +, were investigated, which suggests that their suppression to the PCVG of lead was in the order of Cl- anions and Ni2 +, Co2 + < Fe3 + < Cu2 + for transition metal ions. Under optimized conditions, relative standard derivation (RSD) of 4.4% was achieved from replicate measurements (n = 5) of a standard solution of 0.1 μg L- 1 lead. And, the limit of quantitation (LOQ, 10σ) of 0.012 μg L- 1 lead was obtained using this method and the method blank could be easily controlled down to 0.023 μg L- 1. To validate applicability of this method, it was also employed for the determination of lead in tap water, rain water and lake water.

  4. On-chip electro membrane extraction with online ultraviolet and mass spectrometric detection

    DEFF Research Database (Denmark)

    Petersen, Nickolaj Jacob; Foss, Sunniva Taule; Jensen, Henrik;

    2011-01-01

    Electro membrane extraction was demonstrated in a microfluidic device. The device was composed of a 25 μm thick porous polypropylene membrane bonded between two poly(methyl methacrylate) (PMMA) substrates, each having 50 μm deep channel structures facing the membrane. The supported liquid membrane...

  5. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

  6. Recent developments of nanoparticle-based enrichment methods for mass spectrometric analysis in proteomics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In proteome research, rapid and effective separation strategies are essential for successful protein identification due to the broad dynamic range of proteins in biological samples. Some important proteins are often expressed in ultra low abundance, thus making the pre-concentration procedure before mass spectrometric analysis prerequisite. The main purpose of enrichment is to isolate target molecules from complex mixtures to reduce sample complexity and facilitate the subsequent analyzing steps. The introduction of nanoparticles into this field has accelerated the development of enrichment methods. In this review, we mainly focus on recent developments of using different nanomaterials for pre-concentration of low-abundance peptides/ proteins, including those containing post-translational modifications, such as phosphorylation and glycosylation, prior to mass spectrometric analysis.

  7. The prediction of paper properties from spectrometric data with machine learning

    OpenAIRE

    Jakovac, Alen

    2011-01-01

    In this thesis we present a solution for the problem of predicting the chemical and physical properties of paper from spectrometric data. We used a data set that consists of over 1000 samples of paper. For each sample 15 chemical and physical properties and its near-infrared spectra were measured. We used the following machine learning methods to predict the properties of paper: linear regression, pace regression, a nearest neighbor-based model, regression trees, a support vector machine, ...

  8. Remote mass spectrometric sampling of electrospray- and desorption electrospray-generated ions using an air ejector.

    Science.gov (United States)

    Dixon, R Brent; Bereman, Michael S; Muddiman, David C; Hawkridge, Adam M

    2007-10-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data are presented.

  9. Mass spectrometric identification of proteins and characterization of their post-translational modifications in proteome analysis

    DEFF Research Database (Denmark)

    Roepstorff, P; Larsen, Martin Røssel

    2001-01-01

    dominant strategies for identification of proteins from gels based on peptide mass spectrometric fingerprinting and partial sequencing by mass spectrometry are described. After identification of the proteins the next challenge in proteome analysis is characterization of their post-translational...... modifications. The general problems associated with characterization of these directly from gel separated proteins are described and the current state of art for the determination of phosphorylation, glycosylation and proteolytic processing is illustrated....

  10. A Spectrometric Setup for Synchronous Total Internal Reflection Fluorescence Measurement at the Solid/Liquid Interface

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A spectrometric setup to perform total internal reflection fluorescence (TIRF) and synchronous TIRF measurements at solid/liquid interfaces is presented. The combination of TIRF and synchronous fluorescence was proposed to analyze simultaneously different components at interfaces. The TIRF excitation, emission and synchronous spectra of a water-soluble porphyrin were obtained from water/glass interface using this setup without the existence of a surfactant.

  11. Heterogeneous nuclear ribonucleoproteins C1/C2 identified as autoantigens by biochemical and mass spectrometric methods

    DEFF Research Database (Denmark)

    Heegaard, N H; Larsen, Martin Røssel; Muncrief, T

    2000-01-01

    The antigenic specificity of an unusual antinuclear antibody pattern in three patient sera was identified after separating HeLa-cell nuclear extracts by two-dimensional (2D) gel electrophoresis and localizing the antigens by immunoblotting with patient serum. Protein spots were excised from the 2......-separation methods and mass-spectrometric peptide mapping in combination with database searches are powerful tools in the identification of novel autoantigen specificities....

  12. Combining Mass Spectrometric Metabolic Profiling with Genomic Analysis: A Powerful Approach for Discovering Natural Products from Cyanobacteria.

    Science.gov (United States)

    Kleigrewe, Karin; Almaliti, Jehad; Tian, Isaac Yuheng; Kinnel, Robin B; Korobeynikov, Anton; Monroe, Emily A; Duggan, Brendan M; Di Marzo, Vincenzo; Sherman, David H; Dorrestein, Pieter C; Gerwick, Lena; Gerwick, William H

    2015-07-24

    An innovative approach was developed for the discovery of new natural products by combining mass spectrometric metabolic profiling with genomic analysis and resulted in the discovery of the columbamides, a new class of di- and trichlorinated acyl amides with cannabinomimetic activity. Three species of cultured marine cyanobacteria, Moorea producens 3L, Moorea producens JHB, and Moorea bouillonii PNG, were subjected to genome sequencing and analysis for their recognizable biosynthetic pathways, and this information was then compared with their respective metabolomes as detected by MS profiling. By genome analysis, a presumed regulatory domain was identified upstream of several previously described biosynthetic gene clusters in two of these cyanobacteria, M. producens 3L and M. producens JHB. A similar regulatory domain was identified in the M. bouillonii PNG genome, and a corresponding downstream biosynthetic gene cluster was located and carefully analyzed. Subsequently, MS-based molecular networking identified a series of candidate products, and these were isolated and their structures rigorously established. On the basis of their distinctive acyl amide structure, the most prevalent metabolite was evaluated for cannabinomimetic properties and found to be moderate affinity ligands for CB1.

  13. Ultraviolet irradiation-induced substitution of fluorine with hydroxyl radical for mass spectrometric analysis of perfluorooctane sulfonyl fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Tang, Xuemei; Huang, Lulu; Kang, Jie; Zhong, Hongying, E-mail: hyzhong@mail.ccnu.edu.cn

    2016-01-28

    A rapid and solvent free substitution reaction of a fluorine atom in perfluorooctane sulfonyl fluoride (PFOSF) with a hydroxyl radical is reported. Under irradiation of ultraviolet laser on semiconductor nanoparticles or metal surfaces, hydroxyl radicals can be generated through hole oxidization. Among all fluorine atoms of PFOSF, highly active hydroxyl radicals specifically substitute the fluorine of sulfonyl fluoride functional group. Resultant perfluorooctane sulfonic acid is further ionized through capture of photo-generated electrons that switch the neutral molecules to negatively charged odd electron hypervalent ions. The unpaired electron subsequently initiates α O–H bond cleavage and produces perfluorooctane sulfonate negative ions. Hydroxyl radical substitution and molecular dissociation of PFOSF have been confirmed by masses with high accuracy and resolution. It has been applied to direct mass spectrometric imaging of PFOSF adsorbed on surfaces of plant leaves. - Highlights: • Ultraviolet irradiation on semiconductor nanoparticles produces electron–hole pairs. • Hole oxidization results in the formation of hydroxyl radicals. • Fluorine atoms of PFOSF can be specifically substituted with hydroxyl radicals. • Capture of photoelectrons causes dissociation and fragmentation. • Fragments are detected in negative ion mode.

  14. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry in water samples

    Directory of Open Access Journals (Sweden)

    Arpa Şahin Ç.

    2013-04-01

    Full Text Available A simple, rapid and inexpensive solidified floating organic drop microextraction (SFODME and flow injection flame atomic absorption spectrometric determination (FI-FAAS method for copper was developed. 3-amino-7-dimethylamino-2-methylphenazine (Neutral red, NR was used as the complexing agent. Several factors affecting the microextraction efficiency, such as, pH, NR and sodium dodecylbenzenesulfonate (SDBS concentration, extraction time, stirring rate, and temperature were investigated and optimized. Under optimized experimental conditions an enrichment factor of 541 was obtained for 100 mL of sample solution. The calibration graph was linear in the range of 0.5 – 20.0 ng mL–1 and the limit of detection (3s was 0.18 ng mL–1, the limit of quantification (10s was 0.58 ng mL–1. The relative standard deviation (RSD for 10 replicate measurements of 10 ng mL–1 copper was 2.7%. The developed method was successfully applied to the extraction and determination of copper in different certified reference materials (Estuarine water, Slew 3 and fortified water, TM 23.2 and real water samples and satisfactory results were obtained.

  15. Liquid chromatography-electrothermal atomic absorption spectrometry for the separation and preconcentration of molybdenum in milk and infant formulas.

    Science.gov (United States)

    López-García, I; Viñas, P; Romero-Romero, R; Hernández-Córdoba, M

    2007-08-06

    Two procedures for the electrothermal atomic absorption spectrometric determination of molybdenum in milk and infant formulas using slurried samples are described. For powdered milk samples, 10% (m/v) slurries were prepared in a medium containing 25 and 75% (v/v) concentrated hydrogen peroxide and hydrofluoric acid, respectively, and introduced directly into the furnace. Palladium (200 microg mL(-1)) was used as the modifier and calibration was carried out using aqueous standards prepared in the same medium. The detection limit was 0.02 microg g(-1) for powdered milk samples suspended at 10% (m/v) (equivalent to 2 microg L(-1)). The relative standard deviation (R.S.D.) for five measurements was 1.9%, the characteristic mass being 25 pg. For liquid milk samples, a procedure was proposed based on preconcentration and removal of the matrix, using ionic exchange (Amberlite IRA 743) and elution of molybdenum with 5% (m/v) NaOH. In this case, a 30-fold improvement in the calibration slope was achieved, leading to a detection limit of 0.04 microg L(-1) for liquid samples diluted to 10%. The R.S.D. was 3.5%. Using a size-based separation procedure, it was found that molybdenum is present in its inorganic form or associated to low molecular weight substances in cow milk, while in breast milk it is associated to proteins. The reliability of the procedure was checked by comparing the results obtained with those found using a previous mineralization stage and by analyzing three certified reference materials, namely, BCR 063R (skim milk powder), NBS 1549 (non-fat milk powder) and NBS 8435 (whole milk powder).

  16. First attempt to monitor atmospheric glyoxal using differential absorption lidar

    Science.gov (United States)

    Mei, Liang; Lundin, Patrik; Somesfalean, Gabriel; Hu, Jiandong; Zhao, Guangyu; Svanberg, Sune; Bood, Joakim; Vrekoussis, Mihalis; Papayannis, Alexandros

    2012-11-01

    Glyoxal (CHOCHO), as an indicator of photochemical "hot spots", was for the first time the subject of a differential absorption lidar (DIAL) campaign. The strongest absorption line of glyoxal in the blue wavelength region - 455.1 nm - was chosen as the experimental absorption wavelength. In order to handle the effects of absorption cross-section variation of the interfering gas - nitrogen dioxide (NO2) - three-wavelength DIAL measurements simultaneously detecting glyoxal and NO2, were performed. The differential absorption curves, recorded in July 2012, indicate an extremely low glyoxal concentration in Lund, Sweden, although it is expected to be peaking at this time of the year.

  17. Application of gamma ray spectrometric measurements and VLF-EM data for tracing vein type uranium mineralization

    Directory of Open Access Journals (Sweden)

    Ibrahim Gaafar

    2015-12-01

    Full Text Available This study is an attempt to use the gamma ray spectrometric measurements and VLF-EM data to identify the subsurface structure and map uranium mineralization along El Sela shear zone, South Eastern Desert of Egypt. Many injections more or less mineralized with uranium and associated with alteration processes were recorded in El Sela shear zone. As results from previous works, the emplacement of these injections is structurally controlled and well defined by large shear zones striking in an ENE–WSW direction and crosscut by NW–SE to NNW–SSE fault sets. VLF method has been applied to map the structure and the presence of radioactive minerals that have been delineated by the detection of high uranium mineralization. The electromagnetic survey was carried out to detect the presence of shallow and deep conductive zones that cross the granites along ENE–WSW fracturing directions and to map its spatial distribution. The survey comprised seventy N–S spectrometry and VLF-EM profiles with 20 m separation. The resulted data were displayed as composite maps for K, eU and eTh as well as VLF-Fraser map. Twelve profiles with 100 m separation were selected for detailed description. The VLF-EM data were interpreted qualitatively as well as quantitatively using the Fraser and the Karous–Hjelt filters. Fraser filtered data and relative current density pseudo-sections indicate the presence of shallow and deep conductive zones that cross the granites along ENE–WSW shearing directions. High uranium concentrations found just above the higher apparent current-density zones that coincide with El-Sela shear zone indicate a positive relation between conductivity and uranium minerals occurrence. This enables to infer that the anomalies detected by VLF-EM data are due to the highly conductive shear zone enriched with uranium mineralization extending for more than 80 m.

  18. Analysis of metal cations and inorganic anions in olive oil mill waste waters by atomic absorption spectroscopy and ion chromatography. Detection of metals bound mainly to the organic polymeric fraction.

    Science.gov (United States)

    Arienzo, M; Capasso, R

    2000-04-01

    Metal cations were quantitatively detected by atomic absorption spectrometry in samples of olive oil mill waste waters obtained by a pressure process (omww(1)) (K, 17.1; Mg, 2.72; Ca, 2.24; Na, 0.40; Fe, 0.123; Zn, 0.0630; Mn, 0.0147; Cu, 0.00860 g L(-)(1)) and a centrifugation process (omww(2)) (K, 9.80; Mg, 1.65; Ca, 1.35; Na, 0. 162; Fe, 0.0330; Zn, 0.0301; Mn, 0.00910; Cu, 0.00980 g L(-)(1)). The inorganic anions, determined in the same samples by ion chromatography, proved to be Cl(-), H(2)PO(4)(-), F(-), SO(4)(2)(-), and NO(3)(-) (1.61, 1.05, 0.66, 0.52, and 0.023 g L(-)(1), respectively, in omww(1) and 0.61, 0.40, 0.25, 0.20, and 0.0090 g L(-)(1), respectively, in omww(2)). Most of the metal cations were revealed to be bound to the omww organic polymeric fraction (opf), composed of polysaccharides, phenol polymers, and proteins. Opf relative molecular weight was substantially estimated in the range between 1000 and 30000 Da for approximately 75% and in the range from 30000 to 100000 Da for approximately 25%. The free residual cations pool proved to be neutralized by the inorganic counteranions. Finally, the possible exploitation of this material in agriculture and in environmental biotechnology processes is also discussed in the light of its chemical and biochemical oxygen demand parameters.

  19. Characterisation of organic and conventional sweet basil leaves using chromatographic and flow-injection mass spectrometric (FIMS) fingerprints combined with principal component analysis.

    Science.gov (United States)

    Lu, Yingjian; Gao, Boyan; Chen, Pei; Charles, Denys; Yu, Liangli Lucy

    2014-07-01

    Sweet basil, Ocimum basilicum, is one of the most important and wildly used spices and has been shown to have antioxidant, antibacterial, and anti-diarrheal activities. In this study, high performance liquid chromatographic (HPLC) and flow-injection mass spectrometric (FIMS) fingerprinting techniques were used to differentiate organic and conventional sweet basil leaf samples. Principal component analysis (PCA) of the fingerprints indicated that both HPLC and FIMS fingerprints could effectively detect the chemical differences in the organic and conventional sweet basil leaf samples. This study suggested that the organic basil sample contained greater concentrations of almost all the major compounds than its conventional counterpart on a per same botanical weight basis. The FIMS method was able to rapidly differentiate the organic and conventional sweet basil leaf samples (1min analysis time), whereas the HPLC fingerprints provided more information about the chemical composition of the basil samples with a longer analytical time.

  20. Performance characterization of a quantitative liquid chromatography-tandem mass spectrometric method for 12 macrolide and lincosamide antibiotics in salmon, shrimp and tilapia.

    Science.gov (United States)

    Dickson, Leslie C

    2014-09-15

    This paper describes an extension and performance characterization of a quantitative confirmatory multi-residue liquid chromatography-tandem mass spectrometric method for residues of macrolide and lincosamide antibiotics, originally validated for application to bovine kidney tissues, to tissues of salmon, shrimp and tilapia. The 12 analytes include clindamycin, erythromycin A, gamithromycin, josamycin, lincomycin, neospiramycin 1, oleandomycin, pirlimycin, spiramycin 1, tildipirosin, tilmicosin and tylosin A. The limit of detection was 0.5 μg/kg. Within-laboratory precision evaluated over the analytical range of 5.0-50.0 μg/kg ranged from 4 to 17%. The accuracy of the method ranged from 80 to 112%. Recoveries ranged from 47 to 99% with all but one recovery above 60%. This is the first report of a quantitative confirmatory method for gamithromycin, pirlimycin and tildipirosin in fish and shrimp.

  1. Molecular absorption in transition region spectral lines

    CERN Document Server

    Schmit, Donald; Ayres, Thomas; Peter, Hardi; Curdt, Werner; Jaeggli, Sarah

    2014-01-01

    Aims: We present observations from the Interface Region Imaging Spectrograph (IRIS) of absorption features from a multitude of cool atomic and molecular lines within the profiles of Si IV transition region lines. Many of these spectral lines have not previously been detected in solar spectra. Methods: We examined spectra taken from deep exposures of plage on 12 October 2013. We observed unique absorption spectra over a magnetic element which is bright in transition region line emission and the ultraviolet continuum. We compared the absorption spectra with emission spectra that is likely related to fluorescence. Results: The absorption features require a population of sub-5000 K plasma to exist above the transition region. This peculiar stratification is an extreme deviation from the canonical structure of the chromosphere-corona boundary . The cool material is not associated with a filament or discernible coronal rain. This suggests that molecules may form in the upper solar atmosphere on small spatial scales...

  2. Molecular hydrogen absorption systems in SDSS

    CERN Document Server

    Balashev, S A; Ivanchik, A V; Varshalovich, D A; Petitjean, P; Noterdaeme, P

    2014-01-01

    We present a systematic search for molecular hydrogen absorption systems at high redshift in quasar spectra from the Sloan Digital Sky Survey (SDSS) II Data Release 7 and SDSS-III Data Release 9. We have selected candidates using a modified profile fitting technique taking into account that the Ly$\\alpha$ forest can effectively mimic H$_2$ absorption systems at the resolution of SDSS data. To estimate the confidence level of the detections, we use two methods: a Monte-Carlo sampling and an analysis of control samples. The analysis of control samples allows us to define regions of the spectral quality parameter space where H$_2$ absorption systems can be confidently identified. We find that H$_2$ absorption systems with column densities $\\log {\\rm N_{H_2}} > 19$ can be detected in only less than 3% of SDSS quasar spectra. We estimate the upper limit on the detection rate of saturated H$_2$ absorption systems ($\\log {\\rm N_{H_2}} > 19$) in Damped Ly-$\\alpha$ (DLA) systems to be about 7%. We provide a sample of ...

  3. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...

  4. Implementation of suitable flow injection/sequential-sample separation/preconcentration schemes for determination of trace metal concentrations using detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Wang, Jianhua

    2002-01-01

    Various preconditioning procedures encomprising appropriate separation/preconcentration schemes in order to obtain optimal sensitivity and selectivity characteristics when using electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS) are pres......Various preconditioning procedures encomprising appropriate separation/preconcentration schemes in order to obtain optimal sensitivity and selectivity characteristics when using electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS...

  5. Estimation of thermal neutron absorption cross-section from K, U and Th concentrations for Miocene rocks from the Carpathian Piedmont in Poland using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Loskiewicz, Jerzy E-mail: jerzy.loskiewicz@ifj.edu.pl; Swakon, Jan; Kulczykowska, Krystyna

    2000-06-01

    The radiometric K, U and Th concentrations and neutron absorption cross-section {sigma}{sub a} of rock samples obtained from coring are analysed. The cores are from well bores located in the Sucha-Jordanow region (Carpathian Mountains) and from gas producing Miocene formations in the Carpathian foothills. Correlation coefficients between the neutron absorption cross-section ({sigma}{sub a}) and K, U and Th concentrations are presented. Neural network representation of the function {sigma}{sub a}={integral}(K, U, Th) obtained for a region can later be used for {sigma}{sub a} estimation from spectrometric probe results in uncored wells.

  6. A new ultrasonic-assisted cloud-point-extraction procedure for pre-concentration and determination of ultra-trace levels of copper in selected beverages and foods by flame atomic absorption spectrometry.

    Science.gov (United States)

    Altunay, Nail; Gürkan, Ramazan; Orhan, Ulaş

    2015-01-01

    A new ultrasonic-assisted cloud-point-extraction (UA-CPE) method was developed for the pre-concentration of Cu(II) in selected beverage and food samples prior to flame atomic absorption spectrometric (FAAS) analysis. For this purpose, Safranin T was used as an ion-pairing reagent based on charge transfer in the presence of oxalate as the primary chelating agent at pH 10. Non-ionic surfactant, poly(ethyleneglycol-mono-p-nonylphenylether) (PONPE 7.5) was used as an extracting agent in the presence of NH4Cl as the salting out agent. The variables affecting UA-CPE efficiency were optimised in detail. The linear range for Cu(II) at pH 10 was 0.02-70 µg l(-)(1) with a very low detection limit of 6.10 ng l(-)(1), while the linear range for Cu(I) at pH 8.5 was 0.08-125 µg l(-)(1) with a detection limit of 24.4 ng l(-)(1). The relative standard deviation (RSD %) was in the range of 2.15-4.80% (n = 5). The method was successfully applied to the quantification of Cu(II), Cu(I) and total Cu in selected beverage and food samples. The accuracy of the developed method was demonstrated by the analysis of two standard reference materials (SRMs) as well as recoveries of spiked samples.

  7. Mass spectrometric characterization of the Rosetta Spacecraft contamination

    Science.gov (United States)

    Bieler, A.; Altwegg, K.; Balsiger, H.; Berthelier, J.-J.; Calmonte, U.; Combi, M.; De Keyser, J.; Fiethe, B.; Fuselier, S. A.; Gasc, S.; Gombosi, T.; Hansen, K. C.; Hässig, M.; Korth, A.; Le Roy, L.; Mall, U.; Rème, H.; Rubin, M.; Sémon, T.; Tenishev, V.; Tzou, C.-Y.; Waite, J. H.; Wurz, P.

    2016-09-01

    Mass spectrometers are valuable tools for the in situ characterization of gaseous exo- and atmospheres and have been operated at various bodies in space. Typical measurements derive the elemental composition, relative abundances, and isotopic ratios of the examined environment. To sample tenuous gas environments around comets, icy moons, and the exosphere of Mercury, efficient instrument designs with high sensitivity are mandatory while the contamination by the spacecraft and the sensor itself should be kept as low as possible. With the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA), designed to characterize the coma of comet 67P/Churyumov-Gerasimenko, we were able to quantify the effects of spacecraft contamination on such measurements. By means of 3D computational modeling of a helium leak in the thruster pressurization tubing that was detected during the cruise phase we examine the physics involved leading to the measurements of contamination. 3 types of contamination can be distinguished: i) Compounds from the decomposition of the spacecraft material. ii) Contamination from thruster firing during maneuvers. iii) Adsorption and desorption of the sampled environment on and from the spacecraft. We show that even after more than ten years in space the effects of i) are still detectable by ROSINA and impose an important constraint on the lower limit of gas number densities one can examine by means of mass spectrometry. Effects from ii) act on much shorter time scales and can be avoided or minimized by proper mission planning and data analysis afterwards. iii) is the most difficult effect to quantify as it changes over time and finally carries the fingerprint of the sampled environment which makes prior calibration not possible.

  8. The Application of Atomic Absorption Spectrometry in Automatic Transmission Fault Detection%原子吸收光谱法在汽车自动变速器故障检测中的应用

    Institute of Scientific and Technical Information of China (English)

    陈立旦; 陈开考

    2012-01-01

    The authors studied the innovative applications of atomic absorption spectrometry in the automatic transmission fault detectioa After the authors have determined Fe, Cu and Cr contents in the five groups of Audi A6 main metal in automatic transmission fluid whose travel course is respectively 10~15 thousand kilometers, 20~26 thousand kilometers, 32~38 thousand kilometers, 43~49 thousand kilometers, and 52~58 thousand kilometers by atomic absorption spectrometry, the authors founded the database of primary metal content in the Audi A6 different mileage automatic transmission fluid (ATF). The research discovered that the main metal content in the automatic transmission fluid increased with the vehicles mileage and its normal metal content level in the automatic transmission fluid is between the two trend lines. The authors determined the main metal content of automatic transmission fluid which had faulty symptoms and compared it with its database value. Those can not only judge the wear condition of the automatic transmission which had faulty symptoms but also help the automobile detection and maintenance personnel to diagnose automatic transmission failure reasons without disintegration. This reduced automobile maintenance costs, and improved the quality of automobile maintenance.%研究原子吸收光谱法在汽车自动变速器故障检测中的创新性应用.通过原子吸收光谱法测定行驶里程分别为10 000~15 000,20 000~26 000,32 000~38 000,43 000~49 000,52 000~58 000km五批奥迪A6自动变速器油液(ATF)中主要金属Fe,Cu,Cr的含量,建立奥迪A6自动变速器不同行驶里程数ATF主要金属含量的数据库.研究发现主要金属含量随着汽车行驶里程数上升而增加,并且其正常含量在两条趋势线之间.测定有故障症状的ATF主要金属含量,并与其数据库数值比对,既可以判断自动变速器的磨损状况,也可以帮助汽车检测维修人员在不解体状态下诊断汽车

  9. Peat as a natural solid-phase for copper preconcentration and determination in a multicommuted flow system coupled to flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, A.P.S. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia, 166, 09210-170 Santo Andre (Brazil); Firmino, M.A. [Departamento de Engenharia de Materiais, Escola de Engenharia, Universidade Presbiteriana Mackenzie, Rua da Consolacao, 930, 01302-970 Sao Paulo (Brazil); Nomura, C.S. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia, 166, 09210-170 Santo Andre (Brazil); Rocha, F.R.P.; Oliveira, P.V. [Departamento de Quimica Fundamental, Instituto de Quimica, Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 748, 05508-000 Sao Paulo (Brazil); Gaubeur, I. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia, 166, 09210-170 Santo Andre (Brazil)], E-mail: ivanise.gaubeur@ufabc.edu.br

    2009-03-23

    The physical and chemical characteristics of peat were assessed through measurement of pH, percentage of organic matter, cationic exchange capacity (CEC), elemental analysis, infrared spectroscopy and quantitative analysis of metals by ICP OES. Despite the material showed to be very acid in view of the percentage of organic matter, its CEC was significant, showing potential for retention of metal ions. This characteristic was exploited by coupling a peat mini-column to a flow system based on the multicommutation approach for the in-line copper concentration prior to flame atomic absorption spectrometric determination. Cu(II) ions were adsorbed at pH 4.5 and eluted with 0.50 mol L{sup -1} HNO{sub 3}. The influence of chemical and hydrodynamic parameters, such as sample pH, buffer concentration, eluent type and concentration, sample flow-rate and preconcentration time were investigated. Under the optimized conditions, a linear response was observed between 16 and 100 {mu}g L{sup -1}, with a detection limit estimated as 3 {mu}g L{sup -1} at the 99.7% confidence level and an enrichment factor of 16. The relative standard deviation was estimated as 3.3% (n = 20). The mini-column was used for at least 100 sampling cycles without significant variation in the analytical response. Recoveries from copper spiked to lake water or groundwater as well as concentrates used in hemodialysis were in the 97.3-111% range. The results obtained for copper determination in these samples agreed with those achieved by graphite furnace atomic absorption spectrometry (GFAAS) at the 95% confidence level.

  10. A technique coupling the analyte electrodeposition followed by in-situ stripping with electrothermal atomic absorption spectrometry for analysis of samples with high NaCl contents

    Science.gov (United States)

    Čánský, Zdeněk; Rychlovský, Petr; Petrová, Zuzana; Matousek, J. P.

    2007-03-01

    A technique coupling the analyte electrodeposition followed by in-situ stripping with electrothermal atomic absorption spectrometry has been developed for determination of lead and cadmium in samples with high salt contents. To separate the analyte from the sample matrix, the analyte was in-situ quantitatively electrodeposited on a platinum sampling capillary serving as the cathode (sample volume, 20 μL). The spent electrolyte containing the sample matrix was then withdrawn, the capillary with the analyte deposited was washed with deionized water and the analyte was stripped into a chemically simple electrolyte (5 g/L NH 4H 2PO 4) by reversing the polarity of the electrodeposition circuit. Electrothermal atomization using a suitable optimized temperature program followed. A fully automated manifold was designed for this coupled technique and the appropriate control software was developed. The operating conditions for determination of Pb and Cd in samples with high contents of inorganic salts were optimized, the determination was characterized by principal analytical parameters and its applicability was verified on analyses of urine reference samples. The absolute limits of detection for lead and cadmium (3 σ criterion) in a sample containing 30 g/L NaCl were 8.5 pg and 2.3 pg, respectively (peak absorbance) and the RSD values amounted to 1.6% and 1.9% for lead (at the 40 ng mL - 1 level) and cadmium (at the 4.0 ng mL - 1 level), respectively. These values (and also the measuring sensitivity) are superior to the results attained in conventional electrothermal atomic absorption spectrometric determination of Pb and Cd in pure solutions (5 g/L NH 4H 2PO 4). The sensitivity of the Pb and Cd determination is not affected by the NaCl concentration up to a value of 100 g/L, demonstrating an efficient matrix removal during the electrodeposition step.

  11. Central cooling: absorptive chillers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-08-01

    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  12. Mass-spectrometric REE analysis in sulphide minerals

    Directory of Open Access Journals (Sweden)

    Irina R. Elizarova

    2012-01-01

    Full Text Available The standard samples of diorite, granite and anorthosite (National Centre for Petrographic and Geochemical Research (CRPG CNRS, Nancy, France were analyzed to measure rare-earth element (REE concentrations by the ICP MS method (quadrupole ELAN 9000 DRC-e without preliminary dilution and concentration procedures. The certified values of REE concentrations measured on ELEMENT-2 mass-spectrometer by ICP MS method in Nancy are also well reproduced on ELAN 9000. The mass-spectrometer analytical environment and modes of operation were adjusted to detect REE in sulphide minerals by the example of the pyrite from the PGE Penikat layered intrusion (Finland and chalcopyrite from the Talnakh deposit (Kazakhstan. The total REE content in the pyrite is ca. 3.5 ppm, that is enough to establish Sm-Nd age of pyrite. By the example of State Standard Sample 2463 (Apatite, Russia it is shown how to apply the mineral/chondrite spectra to evaluate the accuracy of the REE analytical results.

  13. Three-dimensional interferometric, spectrometric, and planetary views of Procyon

    CERN Document Server

    Chiavassa, A; Kervella, P; Matter, A; Lopez, B; Collet, R; Magic, Z; Asplund, M

    2012-01-01

    We used a new realistic 3D radiative-hydrodynamical model atmosphere of Procyon generated with the Stagger Code and synthetic spectra computed with the radiative transfer code Optim3D to re-analyze interferometric and spectroscopic data from the optical to the infrared of Procyon. We compute intensity maps in two optical filters centered at 500 and 800 nm (MARK III) and one infrared filter centered at 2200 nm (VINCI). We constructed stellar disk images accounting for the center-to-limb variations and used them to derive visibility amplitudes and closure phases. We provide 3D limb-darkening coefficients in the optical as well as in the infrared. We show that visibility curves and closure phases show clear deviations from circular symmetry from the 3rd lobe on. These deviations are detectable with current interferometers using closure phases. We derive new angular diameters at different wavelengths with two independent methods based on 3D simulations. We find a diameter_Vinci = 5.390 \\pm 0.03 mas that this is c...

  14. 基于可调谐激光二极管吸收光谱的乙炔在线检测系统%Online Detection System on Acetylene with Tunable Diode Laser Absorption Spectroscopy Method

    Institute of Scientific and Technical Information of China (English)

    何启欣; 刘慧芳; 李彬; 潘教青; 王利军; 郑传涛; 王一丁

    2016-01-01

    基于可调谐半导体激光吸收光谱技术,研制了一种近红外乙炔气体检测系统。通过分析近红外波段乙炔分子的吸收谱线特性,选择了1.534μm附近乙炔分子的吸收峰作为吸收谱线。该系统主要由分布反馈激光器、激光器驱动器、单光程对射式气室、光电探测模块及数字式锁相放大器构成。为了测试该检测系统的性能,配备了乙炔气体样品并开展了气体检测实验。实验结果显示,该系统的最小检测下限为0.02%;在体积分数为0.02%~1%范围内,二次谐波幅值与乙炔气体浓度呈现出良好的线性关系。通过长达20 h的稳定性实验测试了检测系统稳定性。鉴于近红外波段石英光纤传输损耗很小,可以将气室及光路部分与电路部分分离,从而可以进行远程气体检测,这是基于量子级联激光器、热光源的乙炔检测系统难以实现的。该系统采用了自主研制的分布反馈激光器驱动器和锁相放大器,结构简单,性价比高,便与集成,在工业现场乙炔浓度检测方面有着良好的应用前景。%Based on tunable diode laser absorption spectroscopy (TDLAS)technique,an acetylene (C2 H2 )online detection sys-tem was developed by using the absorption band at the wavelength of 1.534μm of C2 H2 molecule.The sensing system consists of four modules including a distributed feedback (DFB)laser,a DFB laser driver,a gas cell with single optical path and a data processing module.With the prepared standard C2 H2 gas sample,detailed measurements were carried out to study the detection performance of the system.Experimental results reveal that,the limit of the system (LOD)is about 0.02%;a good linear rela-tionship is observed between C2 H2 gas concentration and the amplitude of the 2f signal is within the range of 0.02%~1%.A long-term measurement lasting for 20 h on a 0.5% C2 H2 gas sample was carried out to test the stability of the system

  15. Complete Bell state measurement with controlled photon absorption and quantum interference

    OpenAIRE

    Tomita, A.

    2000-01-01

    A solid state device to discriminate all the four Bell states is proposed. The device is composed of controlled absorption crystals, rotators, and retarders. The controlled absorption, where the state of one photon affects the absorption of the other photon, is realized by two photon absorption in a cubic crystal. The controlled absorption crystal detects a particular Bell state and is transparent for the other Bell states. The rotators and retarders transform a Bell state to another. This de...

  16. Mass spectrometric methods for the direct elemental and isotopic analysis of solid material

    Science.gov (United States)

    Ganeev, A. A.; Gubal, A. R.; Potapov, S. V.; Agafonova, N. N.; Nemets, V. M.

    2016-04-01

    Methods for the direct analysis of solids have a number of undeniable advantages over the methods that require preliminary dissolution of samples. High sensitivity and selectivity make the direct mass spectrometric techniques the most in-demand. The review concerns spark source mass spectrometry, laser ionization mass spectrometry, laser ablation inductively coupled plasma mass spectrometry, secondary ion mass spectrometry, secondary neutral mass spectrometry and glow discharge mass spectrometry. Basic principles, analytical characteristics and trends in the development of these techniques are discussed. Particular attention is given to applications of the techniques as well as to their competitive advantages and drawbacks. The bibliography includes 123 references.

  17. Malevolent use of radioactive materials: An international exercise in the analysis of gamma-spectrometric data

    DEFF Research Database (Denmark)

    Dowdall, M.; Andersson, Kasper Grann; Palsson, S.E.

    2010-01-01

    with isotopes and activities that present significant challenges with respect to identification and quantification using gamma ray spectrometry. The MALRAD international exercise was designed to provide a practice opportunity for authorities and laboratories to work with synthetic gamma-spectrometric data...... isotopes, irrespective of the detector type involved, all participants were in a position to identify sources and provide estimates of activity. For situations involving shielded sources or special nuclear materials most participants were in a position to provide indications as to what the sources were...

  18. Electron Ionization Mass Spectrometric Study of Some Substituted 1,3-oxazoles

    OpenAIRE

    Salgueiro, Pedro; Dias, Catarina; Carreiras, M. Carmo; Borges, Carlos

    2007-01-01

    Comunicação oral sob a forma painel Heterocyclic compounds are widely used as pharmaceuticals. Tacrine (THA) was the first drug approved for the treatment of Alzheimer’s disease (AD) and a great effort has been made to design and synthesize new THA-analogues in order to evaluate their beneficial effects as therapeutic agents in this disease.1-6 Contrasting with the pharmaceutical interest, mass spectrometric studies of these compounds and of some of its precursors, namely the oxazole and o...

  19. Tandem mass spectrometric fragmentation patterns of known and new steviol glycosides with structure proposals.

    Science.gov (United States)

    Zimmermann, Benno F

    2011-06-15

    Stevia rebaudiana contains several steviol glycosides that have a sweet flavor. They are up to 450 times sweeter than sucrose, but some have an undesirable aftertaste. Up to 2010, ten different steviol glycosides have been described from the leaves or purified extracts of S. rebaudiana. In this paper, the tandem mass spectrometric fragmentation patterns of these ten compounds are compiled, along with a scheme for structural elucidation. This scheme is then applied to 12 steviol glycosides that have not yet been described. The proposed structures of five steviol glycosides have been confirmed by other authors.

  20. Performance analysis of gamma ray spectrometric parameters on digital signal and analog signal processing based MCA systems using NaI(Tl) detector

    Energy Technology Data Exchange (ETDEWEB)

    Kukreti, B.M., E-mail: bharatkuk@gmail.com [Atomic Minerals Directorate for Exploration and Research, Physics Laboratory, Department of Atomic Energy, Nongmynsong, AMD Complex, Shillong, Meghalaya 793019 (India); Sharma, G.K. [Atomic Minerals Directorate for Exploration and Research, Physics Laboratory, Department of Atomic Energy, Nongmynsong, AMD Complex, Shillong, Meghalaya 793019 (India)

    2012-05-15

    Accurate and speedy estimations of ppm range uranium and thorium in the geological and rock samples are most useful towards ongoing uranium investigations and identification of favorable radioactive zones in the exploration field areas. In this study with the existing 5 in. Multiplication-Sign 4 in. NaI(Tl) detector setup, prevailing background and time constraints, an enhanced geometrical setup has been worked out to improve the minimum detection limits for primordial radioelements K{sup 40}, U{sup 238} and Th{sup 232}. This geometrical setup has been integrated with the newly introduced, digital signal processing based MCA system for the routine spectrometric analysis of low concentration rock samples. Stability performance, during the long counting hours, for digital signal processing MCA system and its predecessor NIM bin based MCA system has been monitored, using the concept of statistical process control. Monitored results, over a time span of few months, have been quantified in terms of spectrometer's parameters such as Compton striping constants and Channel sensitivities, used for evaluating primordial radio element concentrations (K{sup 40}, U{sup 238} and Th{sup 232}) in geological samples. Results indicate stable dMCA performance, with a tendency of higher relative variance, about mean, particularly for Compton stripping constants. - Highlights: Black-Right-Pointing-Pointer Geometrical enhancement for ppm range primordial radio elemental determination. Black-Right-Pointing-Pointer Experimental constraints include detector setup, background and counting time. Black-Right-Pointing-Pointer Gamma spectrometric performance monitored on digital and analog MCA systems. Black-Right-Pointing-Pointer Study indicates higher variance of Compton stripping constants on digital MCA system.

  1. Yafet-Kittel-type magnetic ordering in Ni{sub 0.35}Zn{sub 0.65}Fe{sub 2}O{sub 4} ferrite detected by magnetosensitive microwave absorption measurements

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G., E-mail: memodin@yahoo.co [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Coyoacan, DF 04510 Mexico (Mexico); Montiel, H.; Barron, J.F. [Departamento de Tecnociencias, Centro de Ciencias Aplicadas y Desarrollo Tecnologico de la Universidad Nacional Autonoma de Mexico, Mexico, DF 04510 (Mexico); Gutierrez, M.P. [Universidad Anahuac, Mexico Norte, Mexico DF (Mexico); Zamorano, R. [Departamento de Fisica, ESFM-IPN, U. P. Adolfo Lopez Mateos Edificio 9, Av. Instituto Politecnico Nacional S/N, Col. San Pedro Zacatenco, 07738 DF (Mexico)

    2010-02-15

    Magnetosensitive microwave absorption measurements of polycrystalline ferrite Ni{sub 0.35}Zn{sub 0.65}Fe{sub 2}O{sub 4} was carried out at 9.4 GHz (X-band) as a function of temperature. Temperature dependence of the total linewidth (DELTAH{sub pp}) deduced from the resonance spectra showed the passage through the Curie point (T{sub c}approx430 K). Additionally, the plot DELTAH{sub pp} vs. T also indicated the existence of another magnetic phase transition at approx240 K, which can be associated with a Yafet-Kittel-type canting of the magnetic moments. Low-field microwave absorption (LFMA) and the magnetically modulated microwave absorption spectroscopy (MAMMAS) were used to give a further knowledge on this material. For low temperature, these techniques give evidence of a Yafet-Kittel-type canting of the magnetic moments.

  2. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  3. 26. 13-MHz absorption line toward Cassiopeia A

    Energy Technology Data Exchange (ETDEWEB)

    Konovalenko, A.A.; Sodin, L.G.

    1981-07-01

    New observations confirm that the 26.13-MHz absorption line previously detected in the direction toward the radio source Cas A represents a carbon recombination line, not a hyperfine-structure nitrogen line. Some relevant implications are discussed.

  4. Time-resolved visible/near-infrared spectrometric observations of the Galaxy 11 geostationary satellite

    Science.gov (United States)

    Bédard, Donald; Wade, Gregg A.

    2017-01-01

    Time-resolved spectrometric measurements of the Galaxy 11 geostationary satellite were collected on three consecutive nights in July 2014 with the 1.6-m telescope at the Observatoire du Mont-Mégantic in Québec, Canada. Approximately 300 low-resolution spectra (R ≈ 700 , where R = λ / Δλ) of the satellite were collected each night, covering a spectral range between 425 and 850 nm. The two objectives of the experiment were to conduct material-type identification from the spectra and to study how the spectral energy distribution inferred from these measurements varied as the illumination and observation geometry changed on nightly timescales. We present results that indicate the presence of a highly reflective aluminized surface corresponding to the solar concentrator arrays of the Galaxy 11 spacecraft. Although other material types could not be identified using the spectra, the results showed that the spectral energy distribution of the reflected sunlight from the Galaxy 11 spacecraft varied significantly, in a systematic manner, over each night of observation. The variations were quantified using colour indices calculated from the time-resolved spectrometric measurements.

  5. NOVEL SPECTRUM ABSORPTION OPTICAL FIBER METHANE SENSOR

    Institute of Scientific and Technical Information of China (English)

    Wang Shutao; Che Rensheng

    2005-01-01

    Based on spectrum principle and analyzing the infrared absorption spectrum of methane, a kind of optical fiber methane gas sensor and its system are developed. DFBLD(Distributed feedback laser diode) in 1 300 nm waveband is used as illuminant and phase-detecting technology is used to carry out harmonic wave detecting the concentration of methane. The sensitivity can arrive at 10-5.Experiments results show that the performance targets of the sensor such as sensitivity can basically satisfy the requests of methane detection.

  6. Chaotic systems with absorption

    CERN Document Server

    Altmann, Eduardo G; Tél, Tamás

    2013-01-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate $\\kappa$ in terms of the natural conditionally-invariant measure of the system; (ii) an increased multifractality when compared to the spectrum of dimensions $D_q$ obtained without taking absorption and return times into account; and (iii) a generalization of the Kantz-Grassberger formula that expresses $D_1$ in terms of $\\kappa$, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  7. X-ray absorption spectroscopy of metalloproteins.

    Science.gov (United States)

    Ward, Jesse; Ollmann, Emily; Maxey, Evan; Finney, Lydia A

    2014-01-01

    Metalloproteins are enormously important in biology. While a variety of techniques exist for studying metals in biology, X-ray absorption spectroscopy is particularly useful in that it can determine the local electronic and physical structure around the metal center, and is one of the few avenues for studying "spectroscopically silent" metal ions like Zn(II) and Cu(I) that have completely filled valence bands. While X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) are useful for studying metalloprotein structure, they suffer the limitation that the detected signal is an average of all the various metal centers in the sample, which limits its usefulness for studying metal centers in situ or in cell lysates. It would be desirable to be able to separate the various proteins in a mixture prior to performing X-ray absorption studies, so that the derived signal is from one species only. Here we describe a method for performing X-ray absorption spectroscopy on protein bands following electrophoretic separation and western blotting.

  8. Hydrogen Absorption by Niobium.

    Science.gov (United States)

    1982-04-13

    incorporate an independent means for ascertaining surface cleanliness (e.g. AES). The form of the absorption curve in Fig. 7 appears to agree with that...very interesting study and is well within the capabilities of the systen designed, if the surface cleanliness can be assured. Wire specimens have a...assessing surface cleanliness would be an important supporting technique for understanding the results of these measurements. The simple kinetic

  9. Probing radio source environments via HI and OH absorption

    CERN Document Server

    Gupta, N; Saikia, D J; Ghosh, T; Jeyakumar, S; Gupta, Neeraj

    2006-01-01

    We present the results of HI and OH absorption measurements towards a sample of radio sources using the Arecibo 305-m telescope and the GMRT. In total, 27 radio sources were searched for associated 21-cm HI absorption. One totally new HI absorption system was detected against the radio galaxy 3C258, while five previously known HI absorption systems, and one galaxy detected in emission, were studied with improved frequency resolution and/or sensitivity. Our sample included 17 GPS and CSS objects, 4 of which exhibit HI absorption. This detection rate of ~25% compares with a value of ~40% by Vermeulen et al. for similar sources. We detected neither OH emission nor absorption towards any of the sources that were observed at Arecibo, and estimate a limit on the abundance ratio of N(HI)/N(OH)>4x10^6 for 3C258. We have combined our results with those from other available HI searches to compile a sample of 96 radio sources consisting of 27 GPS, 35 CSS, 13 flat spectrum and 21 large sources. The HI absorption detectio...

  10. Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS)

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Celal [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Art and Science, Karadeniz Technical University, 28049 Giresun (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Art and Science, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Art and Science, Pamukkale University, 20020 Denizli (Turkey); Sentuerk, Hasan Basri [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuefekci, Mehmet [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2007-07-19

    A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L{sup -1} HNO{sub 3} in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 {mu}g L{sup -1}. The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

  11. Identifying tissue-specific signal variation in MALDI mass spectrometric imaging by use of an internal standard

    NARCIS (Netherlands)

    Pirman, D.A.; Kiss, A.; Heeren, R.M.A.; Yost, R.A.

    2013-01-01

    Generating analyte-specific distribution maps of compounds in a tissue sample by matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging (MSI) has become a useful tool in numerous areas across the biological sciences. Direct analysis of the tissue sample provides MS images of

  12. Method and apparatus for enhanced sequencing of complex molecules using surface-induced dissociation in conjunction with mass spectrometric analysis

    Science.gov (United States)

    Laskin, Julia [Richland, WA; Futrell, Jean H [Richland, WA

    2008-04-29

    The invention relates to a method and apparatus for enhanced sequencing of complex molecules using surface-induced dissociation (SID) in conjunction with mass spectrometric analysis. Results demonstrate formation of a wide distribution of structure-specific fragments having wide sequence coverage useful for sequencing and identifying the complex molecules.

  13. Corrosion Problems in Absorption Chillers

    Science.gov (United States)

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  14. 气溶胶光热干涉测量系统激发参数研究%Excition Parameter of Measurement System of Aerosol Absorption Detection with Photothermal Interferometry

    Institute of Scientific and Technical Information of China (English)

    李保生; 徐丽梅; 王易诚; 卢荣胜

    2014-01-01

    The aerosol absorption directly influences the spread of light in the atmosphere, and causes the attenuation of light. With advanced folding Jamin interferometer, the interference system is completely set up. During laser heat and cool process, aerosol absorption can be obtained differently. The parameter of laser exciting power has been determined. It is shown that the system of aerosol absorption coefficient is feasible.%气溶胶吸收直接影响光在大气中的传播造成光的衰减。本文采用折返式Jamin偏振干涉结构建立了气溶胶光热干涉实验系统,提出并实验研究了在激光照射(加热)和降温两个阶段分别测量吸收系数的方法,确定了两种方法测量气溶胶吸收系数的激发激光功率,为进一步开展气溶胶吸收系数的实验研究提供了参数支持。

  15. Converting Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2013-01-01

    Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a sample and non-uniform intensity in the reverberation chambers under test. In this study, conversion methods from Sabine absorption...... coefficients to random incidence absorption coefficients are proposed. The overestimations of the Sabine absorption coefficient are investigated theoretically based on Miki's model for porous absorbers backed by a rigid wall or an air cavity, resulting in conversion factors. Additionally, three optimizations...

  16. Acoustic Absorption Characteristics of People.

    Science.gov (United States)

    Kingsbury, H. F.; Wallace, W. J.

    1968-01-01

    The acoustic absorption characteristics of informally dressed college students in typical classroom seating are shown to differ substantially from data for formally dressed audiences in upholstered seating. Absorption data, expressed as sabins per person or absorption coefficient per square foot, shows that there is considerable variation between…

  17. Mass spectrometric characterization of a prolyl hydroxylase inhibitor GSK1278863, its bishydroxylated metabolite, and its implementation into routine doping controls.

    Science.gov (United States)

    Thevis, Mario; Milosovich, Susan; Licea-Perez, Hermes; Knecht, Dana; Cavalier, Tom; Schänzer, Wilhelm

    2016-08-01

    Drug candidates, which have the potential of enhancing athletic performance represent a risk of being misused in elite sport. Therefore, there is a need for early consideration by anti-doping authorities and implementation into sports drug testing programmes. The hypoxia-inducible factor (HIF) or prolyl hydroxylase inhibitor (PHI) GSK1278863 represents an advanced candidate of an emerging class of therapeutics that possess substantial potential for abuse in sport due to their capability to stimulate the biogenesis of erythrocytes and, consequently, the individual's oxygen transport capacity. A thorough characterization of such analytes by technologies predominantly used for doping control purposes and the subsequent implementation of the active drug and/or its main urinary metabolite(s) are vital for comprehensive, preventive, and efficient anti-doping work. In the present study, the HIF PHI drug candidate GSK1278863 (comprising a 6-hydroxypyrimidine-2,4-dione nucleus) and its bishydroxylated metabolite M2 (GSK2391220A) were studied regarding their mass spectrometric behaviour under electrospray ionization (ESI-MS/MS) conditions. Synthesized reference materials were used to elucidate dissociation pathways by means of quadrupole/time-of-flight high resolution/high accuracy tandem mass spectrometry, and their detection from spiked urine and elimination study urine samples under routine doping control conditions was established using liquid chromatography-electrospray ionization-tandem mass spectrometry with direct injection. Dissociation pathways to diagnostic product ions of GSK1278863 (e.g. m/z 291, 223, and 122) were proposed as substantiated by determined elemental compositions and MS(n) experiments as well as comparison to spectra of the bishydroxylated analogue M2. An analytical assay based on direct urine injection using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of GSK1278863 in

  18. Absorption heat pumps

    Science.gov (United States)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.

    1987-03-01

    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  19. Gas chromatography-mass spectrometric method for metabolic profiling of tobacco leaves.

    Science.gov (United States)

    Li, Yong; Pang, Tao; Li, Yanli; Wang, Xiaolin; Li, Qinghua; Lu, Xin; Xu, Guowang

    2011-06-01

    A gas chromatography-mass spectrometric method was developed for profiling of tobacco leaves. The differentiation among tobacco leaves planted in two different regions was investigated. Prior to analysis, the extraction solvent formulation was optimized and a combination of water, methanol and acetonitrile with a volume ratio of 3:1:1 was found to be optimal. The reproducibility of the method was satisfactory. Kendall tau-b rank correlation coefficients were equal to 1 (pleaves from Zimbabwe and Yunnan of China. Our result revealed that levels of saccharides and their derivatives including xylose, ribose, fructose, glucose, turanose, xylitol and glyceric acid were more abundant while sucrose, glucitol and D-gluconic acid were less abundant in tobacco leaves from Yunnan as compared to those from Zimbabwe. Amino acids such as L-alanine, L-tyrosine and L-threonine were found to be richer in Zimbabwe tobacco than in Yunnan tobacco.

  20. Considerations for quantification of lipids in nerve tissue using MALDI mass spectrometric imaging

    Science.gov (United States)

    Landgraf, Rachelle R.; Garrett, Timothy J.; Prieto Conaway, Maria C.; Calcutt, Nigel A.; Stacpoole, Peter W.; Yost, Richard A.

    2013-01-01

    MALDI mass spectrometric imaging is a technique that provides the ability to identify and characterize endogenous and exogenous compounds spatially within tissue with relatively little sample preparation. While it is a proven methodology for qualitative analysis, little has been reported for its utility in quantitative measurements. In the current work, inherent challenges in MALDI quantification are addressed. Signal response is monitored over successive analyses of a single tissue section to minimize error due to variability in the laser, matrix application, and sample inhomogeneity. Methods for the application of an internal standard to tissue sections are evaluated and used to quantify endogenous lipids in nerve tissue. A precision of 5% or less standard error was achieved, illustrating that MALDI imaging offers a reliable means of in situ quantification for microgram-sized samples and requires minimal sample preparation. PMID:21953974

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-12-15

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

  2. A superheterodyne spectrometer for electronic paramagnetic. Resonance; Spectrometre superheterodyne de resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Laffon, J.L. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1963-12-15

    After a few generalities about electron paramagnetic resonance, a consideration of different experimental techniques authorises the choice of a particular type of apparatus. An EPR superheterodyne spectrometer built in the laboratory and having a novel circuit is described in detail. With this apparatus, many experimental results have been obtained and some of these are described as example. (author) [French] Apres quelques generalites sur le phenomene de resonance paramagnetique electronique, une synthese des differentes techniques experimentales, permet de fixer le choix d'un type d'appareillage. Un spectrometre de RPE superheterodyne realise en laboratoire et comportant un circuit original est expose dans le detail. Cet appareil a permis de nombreux resultats experimentaux dont quelques-uns sont decrits a titre d'exemple. (auteur)

  3. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

  4. MASS SPECTROMETRIC ANALYSIS FOR THE IDENTIFICATION OF THUNNUS GENUS FOUR SPECIES

    Directory of Open Access Journals (Sweden)

    T. Pepe

    2011-01-01

    Full Text Available An accurate identification of similar fish species is necessary to prevent illegal substitution and is imposed by labeling regulations in UE countries (1. The genus Thunnus comprises many species of different quality and commercial value. The increasing trade of fish preparations of the species included in this genus and the consequent loss of the external anatomical and morphological features enables fraudulent substitutions. This study reports data relating to the proteomic analysis of four tuna species (T. thynnus, T. alalunga, T. albacares, T. obesus. Sarcoplasmic proteins were studied by mono and two dimensional electrophoresis. The most significant proteins for the characterization of the species were analyzed by mass spectrometric techniques. As reported in a previous study (2, an accurate identification of the species seems possible, owing to the polymorphism displayed by the species of the Thunnus genus.

  5. The 3D inversion of airborne gamma-ray spectrometric data

    Science.gov (United States)

    Minty, Brian; Brodie, Ross

    2016-07-01

    We present a new method for the inversion of airborne gamma-ray spectrometric line data to a regular grid of radioelement concentration estimates on the ground. The method incorporates the height of the aircraft, the 3D terrain within the field of view of the spectrometer, the directional sensitivity of rectangular detectors, and a source model comprising vertical rectangular prisms with the same horizontal dimensions as the required grid cell size. The top of each prism is a plane surface derived from a best-fit plane to the digital elevation model of the earth's surface within each grid cell area. The method is a significant improvement on current methods, and gives superior interpolation between flight lines. It also eliminates terrain effects that would normally remain in the data after the conventional processing of these data assuming a flat-earth model.

  6. Proteogenomics meets cancer immunology: mass spectrometric discovery and analysis of neoantigens.

    Science.gov (United States)

    Polyakova, Anna; Kuznetsova, Ksenia; Moshkovskii, Sergei

    2015-01-01

    Cancer proteogenomics is an emerging field that aims to identify and quantify protein sequence changes associated with the cancer genome. Besides being involved in cancer development and progression, such protein variants may serve as neoantigens, which provide the T-cell response against tumors. Mass spectrometry-based proteogenomics may be a promising tool for finding neoantigens in individual specimens. It is partly based on a technical background accumulated from mass spectrometric studies of peptide ligands of major histocompatibility complex proteins. Examples of the use of mass spectrometry in neoantigen identification are reviewed in this article. Some experimental workflows are discussed, which may use shotgun and targeted proteomics for translational human studies of neoepitopes, such as cancer vaccine development and checkpoint therapy response prediction.

  7. Laser Spectrometric Measurement System for Local Express Diagnostics of Flame at Combustion of Liquid Hydrocarbon Fuels

    Science.gov (United States)

    Kobtsev, V. D.; Kozlov, D. N.; Kostritsa, S. A.; Smirnov, V. V.; Stel'makh, O. M.; Tumanov, A. A.

    2016-03-01

    A laboratory laser spectrometric measurement system for investigation of spatial distributions of local temperatures in a flame at combustion of vapors of various liquid hydrocarbon fuels in oxygen or air at atmospheric pressure is presented. The system incorporates a coherent anti-Stokes Raman spectrometer with high spatial resolution for local thermometry of nitrogen-containing gas mixtures in a single laser shot and a continuous operation burner with a laminar diffusion flame. The system test results are presented for measurements of spatial distributions of local temperatures in various flame zones at combustion of vapor—gas n-decane/nitrogen mixtures in air. Its applicability for accomplishing practical tasks in comparative laboratory investigation of characteristics of various fuels and for research on combustion in turbulent flames is discussed.

  8. Regime transition in electromechanical fluid atomization and implications to analyte ionization for mass spectrometric analysis.

    Science.gov (United States)

    Forbes, Thomas P; Degertekin, F Levent; Fedorov, Andrei G

    2010-11-01

    The physical processes governing the transition from purely mechanical ejection to electromechanical ejection to electrospraying are investigated through complementary scaling analysis and optical visualization. Experimental characterization and visualization are performed with the ultrasonically-driven array of micromachined ultrasonic electrospray (AMUSE) ion source to decouple the electrical and mechanical fields. A new dimensionless parameter, the Fenn number, is introduced to define a transition between the spray regimes, in terms of its dependence on the characteristic Strouhal number for the ejection process. A fundamental relationship between the Fenn and Strouhal numbers is theoretically derived and confirmed experimentally in spraying liquid electrolytes of different ionic strength subjected to a varying magnitude electric field. This relationship and the basic understanding of the charged droplet generation physics have direct implications on the optimal ionization efficiency and mass spectrometric response for different types of analytes.

  9. Quantitative Mass Spectrometric Analysis and Post-Extraction Stability Assessment of the Euglenoid Toxin Euglenophycin

    Directory of Open Access Journals (Sweden)

    Paul V. Zimba

    2013-09-01

    Full Text Available Euglenophycin is a recently discovered toxin produced by at least one species of euglenoid algae. The toxin has been responsible for several fish mortality events. To facilitate the identification and monitoring of euglenophycin in freshwater ponds, we have developed a specific mass spectrometric method for the identification and quantitation of euglenophycin. The post-extraction stability of the toxin was assessed under various conditions. Euglenophycin was most stable at room temperature. At 8 °C there was a small, but statistically significant, loss in toxin after one day. These methods and knowledge of the toxin’s stability will facilitate identification of the toxin as a causative agent in fish kills and determination of the toxin’s distribution in the organs of exposed fish.

  10. Determination of Mass Spectrometric Sensitivity of Different Metalloporphyrin Esters Relative to Porphyrin Ester

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Møller, J.

    1977-01-01

    Quantitative determination of metalloporphyrin contamination in preparations of biologically important porphyrins was achieved mass spectrometrically by application of the integrated ion current technique. For this purpose, the relative molecular ion sensitivities of the contaminating metal compl...... complexes were determined from the ratios of the integrated molecular ion currents of a series of calibration samples containing a porphyrin ester and one of its metal complexes in known molar ratio. Complexes formed with divalent ions of Cu, Zn, Fe, Co and Ni of copro- as well as uro......-prophyrin permethylester were all found to have the same molecular ion sensitivities as their metal-free porphyrin ester. The relative metalloporphyrin ester content in a sample of porphyrin ester was thus obtained directly as the integrated ion current ratios of the normalized molecular ions. The preparation...

  11. Combination of electrochemical, spectrometric and other analytical techniques for high throughput screening of pharmaceutically active compounds.

    Science.gov (United States)

    Suzen, Sibel; Ozkan, Sibel A

    2010-08-01

    Recently, use of electrochemistry and combination of this method with spectroscopic and other analytical techniques are getting one of the important approaches in drug discovery and research as well as quality control, drug stability, determination of physiological activity, measurement of neurotransmitters. Many fundamental physiological processes are depending on oxido-reduction reactions in the body. Therefore, it may be possible to find connections between electrochemical and biochemical reactions concerning electron transfer pathways. Applications of electrochemical techniques to redox-active drug development and studies are one of the recent interests in drug discovery. In this review, the latest developments related to the use of electrochemical techniques in drug research in order to evaluate possible combination spectrometric methods with electrochemical techniques.

  12. Absorption in dielectric models

    CERN Document Server

    Churchill, R J

    2015-01-01

    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  13. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)

    IOAN MAC

    2009-01-01

    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  14. Laser ablation inductively coupled plasma mass spectrometric analyses of base metals in arctic char (Salvelinus alpinus) otoliths collected from a flooded base metal mine.

    Science.gov (United States)

    Friedrich, Lisa A; Halden, Norman M

    2011-05-15

    Otoliths from arctic char recovered from the water body formed from an abandoned open-pit nickel-copper mine contain a trace element record related to the geology of the immediate watershed, past mining activity in the area, and the fish's diet. Laser ablation inductively coupled plasma mass spectrometric analyses across the annular structure of the otoliths detected trace amounts of nickel, copper, and chromium believed to be related to the metal-bearing, mafic-ultramafic minerals in the pit. Oscillatory strontium, barium, and zinc profiles may reflect changing water temperature, diet, or fish metabolism. Lead was detected in very low concentrations and may be related to anthropogenic influence. This closed lake system provides a unique opportunity to study an introduced exotic species in a setting where neither migration nor recruitment have been possible. The fish have successfully occupied the lake and continue to breed despite the influence of the surrounding rocks and local contamination. The chemical record retained within otoliths provides a method of monitoring trace elements affecting fish on a yearly basis and may be regarded as a useful assessment tool for examining the exposure of wild organisms to trace elements.

  15. Sublimation as a method of matrix application for mass spectrometric imaging.

    Science.gov (United States)

    Hankin, Joseph A; Barkley, Robert M; Murphy, Robert C

    2007-09-01

    Common organic matrix-assisted laser desorption/ionization (MALDI) matrices, 2,5-dihydroxybenzoic acid, 3,5-dimethoxy-4-hydroxycinnamic acid, and alpha-cyano-4-hydroxycinnamic acid, were found to undergo sublimation without decomposition under conditions of reduced pressure and elevated temperature. This solid to vapor-phase transition was exploited to apply MALDI matrix onto tissue samples over a broad surface in a solvent-free application for mass spectrometric imaging. Sublimation of matrix produced an even layer of small crystals across the sample plate. The deposition was readily controlled with time, temperature, and pressure settings and was highly reproducible from one sample to the next. Mass spectrometric images acquired from phospholipid standards robotically spotted onto a MALDI plate yielded a more intense, even signal with fewer sodium adducts when matrix was applied by sublimation relative to samples where matrix was deposited by an electrospray technique. MALDI matrix could be readily applied to tissue sections on glass slides and stainless steel MALDI plate inserts as long as good thermal contact was made with the condenser of the sublimation device. Sections of mouse brain were coated with matrix applied by sublimation and were imaged using a Q-q-TOF mass spectrometer to yield mass spectral images of very high quality. Image quality is likely enhanced by several features of this technique including the microcrystalline morphology of the deposited matrix, increased purity of deposited matrix, and evenness of deposition. This inexpensive method was reproducible and eliminated the potential for spreading of analytes arising from solvent deposition during matrix application.

  16. GNU polyxmass: a software framework for mass spectrometric simulations of linear (bio-polymeric analytes

    Directory of Open Access Journals (Sweden)

    Rusconi Filippo

    2006-04-01

    Full Text Available Abstract Background Nowadays, a variety of (bio-polymers can be analyzed by mass spectrometry. The detailed interpretation of the spectra requires a huge number of "hypothesis cycles", comprising the following three actions 1 put forth a structural hypothesis, 2 test it, 3 (invalidate it. This time-consuming and painstaking data scrutiny is alleviated by using specialized software tools. However, all the software tools available to date are polymer chemistry-specific. This imposes a heavy overhead to researchers who do mass spectrometry on a variety of (bio-polymers, as each polymer type will require a different software tool to perform data simulations and analyses. We developed a software to address the lack of an integrated software framework able to deal with different polymer chemistries. Results The GNU polyxmass software framework performs common (bio-chemical simulations–along with simultaneous mass spectrometric calculations–for any kind of linear bio-polymeric analyte (DNA, RNA, saccharides or proteins. The framework is organized into three modules, all accessible from one single binary program. The modules let the user to 1 define brand new polymer chemistries, 2 perform quick mass calculations using a desktop calculator paradigm, 3 graphically edit polymer sequences and perform (bio-chemical/mass spectrometric simulations. Any aspect of the mass calculations, polymer chemistry reactions or graphical polymer sequence editing is configurable. Conclusion The scientist who uses mass spectrometry to characterize (bio-polymeric analytes of different chemistries is provided with a single software framework for his data prediction/analysis needs, whatever the polymer chemistry being involved.

  17. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  18. Microwave absorption measurements in the complex perovskite Pb(Fe{sub 0.5}Ta{sub 0.5})O{sub 3}: Detection of short-range orderly regions

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G., E-mail: memodin@yahoo.com [Seccion de Estudios de Posgrado e Investigacion, ESFM-IPN, U.P. Adolfo Lopez Mateos Edificio 9, Av. Instituto Politecnico Nacional S/N, San Pedro Zacatenco, Mexico DF 07738 (Mexico); Montiel, H. [Departamento de Tecnociencias, Centro de Ciencias Aplicadas y Desarrollo Tecnologico de la Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Mexico DF 04510 (Mexico); Castellanos, M.A. [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Mexico DF 04510 (Mexico); Heiras, J. [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Km. 107, Carretera Tijuana Ensenada, Ensenada, Baja California 22860 (Mexico); Zamorano, R. [Seccion de Estudios de Posgrado e Investigacion, ESFM-IPN, U.P. Adolfo Lopez Mateos Edificio 9, Av. Instituto Politecnico Nacional S/N, San Pedro Zacatenco, Mexico DF 07738 (Mexico)

    2011-10-17

    Highlights: {yields} LFMA spectra showed straight lines with positive slope and non-hysteretic traces. {yields} The spectral changes for the plot of the slope vs. temperature give evidence of the formation of iron clusters. {yields} These small orderly regions of iron ions generate short-range magnetic correlations, and that they produce changes in dynamics of microwave absorption. - Abstract: An electron paramagnetic resonance (EPR) study of the complex perovskite Pb(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} (PFT) at X-band (8.8-9.8 GHz) is presented. The EPR spectra show a single broad line in the 300-480 K temperature range, attributable to Fe{sup 3+} (S = 5/2) ions. The temperature dependence of the EPR parameters: the peak-to-peak linewidth ({Delta}H{sub pp}), the resonance field (H{sub res}) and the integrated intensity (I{sub EPR}), suggests the existence of short-range magnetic correlations; which are associated with the presence of small orderly regions of iron ions in B-sites of the perovskites-type structure, and that they give origin to formation of iron clusters. Low-field microwave absorption (LFMA) is used to give further knowledge on this material; where this technique also gives evidence of these short-range orderly regions.

  19. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients...... into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...

  20. Determination of ruthenium in pharmaceutical compounds by graphite furnace atomic absorption spectroscopy.

    Science.gov (United States)

    Jia, Xiujuan; Wang, Tiebang; Bu, Xiaodong; Tu, Qiang; Spencer, Sandra

    2006-04-11

    A graphite furnace atomic absorption (GFAA) spectrometric method for the determination of ruthenium (Rh) in solid and liquid pharmaceutical compounds has been developed. Samples are dissolved or diluted in dimethyl sulfoxide (DMSO) without any other treatment before they were analyzed by GFAA with a carefully designed heating program to avoid pre-atomization signal loss and to achieve suitable sensitivity. Various inorganic and organic solvents were tested and compared and DMSO was found to be the most suitable. In addition, ruthenium was found to be stable in DMSO for at least 5 days. Spike recoveries ranged from 81 to 100% and the limit of quantitation (LOQ) was determined to be 0.5 microg g(-1) for solid samples or 0.005 microg ml(-1) for liquid samples based a 100-fold dilution. The same set of samples was also analyzed by ICP-MS with a different sample preparation method, and excellent agreement was achieved.

  1. Comparison of the absorption, excretion, and metabolism of suxibuzone and phenylbutazone in humans.

    Science.gov (United States)

    Yasuda, Y; Shindo, T; Mitani, N; Ishida, N; Oono, F; Kageyama, T

    1982-05-01

    The absorption, excretion, and metabolism of a single oral dose of suxibuzone, a new nonsteroidal anti-inflammatory agent, in healthy male volunteers were compared with those of phenylbutazone. After oral administration of either suxibuzone or phenylbutazone, phenylbutazone, oxyphenbutazone, and gamma-hydroxyphenylbutazone were found in the plasma; phenylbutazone was the main metabolite of suxibuzone and phenylbutazone. In the urine, p-gamma-dihydroxyphenylbutazone and several glucuronide conjugates also were found. Spectrometric and/or enzymatic analysis showed that these glucuronide conjugates were suxibuzone glucuronide, 4-hydroxymethylphenylbutazone glucuronide, 4-hydroxymethyloxyphenbutazone glucuronide, oxyphenbutazone glucuronide, and phenylbutazone glucuronides (two types: O-glucuronide and C-4-glucuroxide) after suxibuzone administration, and oxyphenbutazone glucuronide and phenylbutazone glucuronide after phenylbutazone administration. The conjugates specific to suxibuzone administration, suxibuzone glucuronide, 4-hydroxymethylphenylbutazone glucuronide, and 4-hydroxymethyloxyphenbutazone glucuronide, were excreted in the first 6 hr urine. These findings and the pharmacokinetics of these metabolites in the plasma and urine show that suxibuzone is a prodrug of phenylbutazone.

  2. Automated on-line liquid–liquid extraction system for temporal mass spectrometric analysis of dynamic samples

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Kai-Ta; Liu, Pei-Han [Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan (China); Urban, Pawel L. [Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan (China); Institute of Molecular Science, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan (China)

    2015-09-24

    Most real samples cannot directly be infused to mass spectrometers because they could contaminate delicate parts of ion source and guides, or cause ion suppression. Conventional sample preparation procedures limit temporal resolution of analysis. We have developed an automated liquid–liquid extraction system that enables unsupervised repetitive treatment of dynamic samples and instantaneous analysis by mass spectrometry (MS). It incorporates inexpensive open-source microcontroller boards (Arduino and Netduino) to guide the extraction and analysis process. Duration of every extraction cycle is 17 min. The system enables monitoring of dynamic processes over many hours. The extracts are automatically transferred to the ion source incorporating a Venturi pump. Operation of the device has been characterized (repeatability, RSD = 15%, n = 20; concentration range for ibuprofen, 0.053–2.000 mM; LOD for ibuprofen, ∼0.005 mM; including extraction and detection). To exemplify its usefulness in real-world applications, we implemented this device in chemical profiling of pharmaceutical formulation dissolution process. Temporal dissolution profiles of commercial ibuprofen and acetaminophen tablets were recorded during 10 h. The extraction-MS datasets were fitted with exponential functions to characterize the rates of release of the main and auxiliary ingredients (e.g. ibuprofen, k = 0.43 ± 0.01 h{sup −1}). The electronic control unit of this system interacts with the operator via touch screen, internet, voice, and short text messages sent to the mobile phone, which is helpful when launching long-term (e.g. overnight) measurements. Due to these interactive features, the platform brings the concept of the Internet-of-Things (IoT) to the chemistry laboratory environment. - Highlights: • Mass spectrometric analysis normally requires sample preparation. • Liquid–liquid extraction can isolate analytes from complex matrices. • The proposed system automates

  3. MALDI-mass spectrometric imaging revealing hypoxia-driven lipids and proteins in a breast tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jiang; Chughtai, Kamila; Purvine, Samuel O.; Bhujwalla, Zaver M.; Raman, Venu; Pasa-Tolic, Ljiljana; Heeren, Ronald M.; Glunde, Kristine

    2015-06-16

    Hypoxic areas are a common feature of rapidly growing malignant tumors and their metastases, and are typically spatially heterogeneous. Hypoxia has a strong impact on tumor cell biology and contributes to tumor progression in multiple ways. To date, only a few molecular key players in tumor hypoxia, such as for example hypoxia-inducible factor-1 (HIF-1), have been discovered. The distribution of biomolecules is frequently heterogeneous in the tumor volume, and may be driven by hypoxia and HIF-1α. Understanding the spatially heterogeneous hypoxic response of tumors is critical. Mass spectrometric imaging (MSI) provides a unique way of imaging biomolecular distributions in tissue sections with high spectral and spatial resolution. In this paper, breast tumor xenografts grown from MDA-MB-231-HRE-tdTomato cells, with a red fluorescent tdTomato protein construct under the control of a hypoxia response element (HRE)-containing promoter driven by HIF-1α, were used to detect the spatial distribution of hypoxic regions. We elucidated the 3D spatial relationship between hypoxic regions and the localization of small molecules, metabolites, lipids, and proteins by using principal component analysis – linear discriminant analysis (PCA-LDA) on 3D rendered MSI volume data from MDA-MB-231-HRE-tdTomato breast tumor xenografts. In this study we identified hypoxia-regulated proteins active in several distinct pathways such as glucose metabolism, regulation of actin cytoskeleton, protein folding, translation/ribosome, splicesome, the PI3K-Akt signaling pathway, hemoglobin chaperone, protein processing in endoplasmic reticulum, detoxification of reactive oxygen species, aurora B signaling/apoptotic execution phase, the RAS signaling pathway, the FAS signaling pathway/caspase cascade in apoptosis and telomere stress induced senescence. In parallel we also identified co-localization of hypoxic regions and various lipid species such as PC(16:0/18:1), PC(16:0/18:2), PC(18:0/18:1), PC

  4. 微波消解-原子吸收测定柠檬中的 Cu、Zn、Fe 的含量%Microwave Digestion-Detection of Cu,Zn and Fe through Atomic Absorption

    Institute of Scientific and Technical Information of China (English)

    李兴华

    2015-01-01

    This experiment aims to ,using flame atomic absorption spectrometry ,determine through specific ab-sorption procedure the contents of copper , zinc, iron in different parts of lemons when the best atomic absorp-tion spectrometer works.The findings suggest that contents of Cu ,Zn and Fe are respectively 0.709μg/kg,1. 244μg/kg and 14.312μg/kg in lemon juice,0.787μg/kg,2.430μg/kg and 12.971μg/kg in lemon peel,and 3.384μg/kg,5.948μg/kg and 29.773μg/kg in lemon seeds.The experiment provides reference for the safety control of lemon as one of our advantageous fruit resources .%实验对柠檬果实不同部位按照特定的消解程序进行消解,铜、锌、铁三种元素在最佳原子吸收光谱仪工作条件下,采用火焰原子吸收光谱法对其含量进行测定。柠檬果实中,不同部位中铜、锌、铁含量分别为柠檬果汁:0.709μg/kg,1.244μg/kg,14.312μg/kg;柠檬果皮:0.787μg/kg,2.430μg/kg、12.971μg/kg;柠檬籽:3.384μg/kg,5.948μg/kg,29.773μg/kg。实验所建立的柠檬重金属含量测定方法可为四川省优势资源果蔬柠檬的质量安全奠定基础。

  5. Development of an automated sequential injection on-line solvent extraction-back extraction procedure as demonstrated for the determination of cadmium with detection by electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2002-01-01

    An automated sequential injection (SI) on-line solvent extraction-back extraction separation/preconcentration procedure is described. Demonstrated for the assay of cadmium by electrothermal atomic absorption spectrometry (ETAAS), the analyte is initially complexed with ammonium...... pyrrolidinedithiocarbamate (APDC) in citrate buffer and the chelate is extracted into isobutyl methyl ketone (IBMK), which is separated from the aqueous phase by means of a newly designed dual-conical gravitational phase separator. A metered amount of the organic eluate is aspirated and stored in the PTFE holding coil (HC......) of the SI-system. Afterwards, it is dispensed and mixed with an aqueous back extractant of dilute nitric acid containing Hg(II) ions as stripping agent, thereby facilitating a rapid metal-exchange reaction with the APDC ligand and transfer of the Cd into the aqueous phase. The aqueous phase is separated...

  6. Absorption intestinale des vitamines liposolubles

    OpenAIRE

    Reboul Emmanuelle

    2011-01-01

    The molecular mechanisms of fat-soluble vitamin intestinal absorption remain partly unknown, despite the fact that a better understanding of this process would certainly allow to improve their bioavailability. If their digestion-absorption process follows the fate of lipids globally, the recent discovery of membranes proteins involved in their absorption questioned the established dogmas. These new data should be taken into account to avoid dietary or drug interactions that may limit some fat...

  7. Absorption intestinale des vitamines liposolubles

    Directory of Open Access Journals (Sweden)

    Reboul Emmanuelle

    2011-03-01

    Full Text Available The molecular mechanisms of fat-soluble vitamin intestinal absorption remain partly unknown, despite the fact that a better understanding of this process would certainly allow to improve their bioavailability. If their digestion-absorption process follows the fate of lipids globally, the recent discovery of membranes proteins involved in their absorption questioned the established dogmas. These new data should be taken into account to avoid dietary or drug interactions that may limit some fatsoluble vitamin bioavailability.

  8. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry.

    Science.gov (United States)

    Sahin, Ciğdem Arpa; Tokgöz, Ilknur

    2010-05-14

    A rapid, simple and cost effective solidified floating organic drop microextraction (SFODME) and flow injection flame atomic absorption spectrometric determination (FI-FAAS) method for copper was developed. In this method, a free microdrop of 1-undecanol containing 1,5-diphenyl carbazide (DPC) as the complexing agent was transferred to the surface of an aqueous sample including Cu(II) ions, while being agitated by a stirring bar in the bulk of the solution. Under the proper stirring conditions, the suspended microdrop can remain at the top-center position of the aqueous sample. After the completion of the extraction, the sample vial was cooled by placing it in a refrigerator for 10min. The solidified microdrop was then transferred into a conical vial, where it melted immediately and diluted to 300microL with ethanol. Finally, copper ions in 200microL of diluted solution were determined by FI-FAAS. Several factors affecting the microextraction efficiency, such as type of extraction solvent, pH, complexing agent concentration, extraction time, stirring rate, sample volume and temperature were investigated and optimized. Under optimized conditions for 100mL of solution, the preconcentration factor was 333 and the enrichment factor was 324. The limit of detection (3s) was 0.4ngmL(-1), the limit of quantification (10s) was 1.1ngmL(-1) and the relative standard deviation (RSD) for 10 replicate measurements of 10ngmL(-1) copper was 0.9%. The proposed method was successfully applied to the determination of copper in different water samples.

  9. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  10. Trace gas absorption spectroscopy using functionalized microring resonators.

    Science.gov (United States)

    Stievater, Todd H; Pruessner, Marcel W; Park, Doewon; Rabinovich, William S; McGill, R Andrew; Kozak, Dmitry A; Furstenberg, Robert; Holmstrom, Scott A; Khurgin, Jacob B

    2014-02-15

    We detect trace gases at parts-per-billion levels using evanescent-field absorption spectroscopy in silicon nitride microring resonators coated with a functionalized sorbent polymer. An analysis of the microring resonance line shapes enables a measurement of the differential absorption spectra for a number of vapor-phase analytes. The spectra are obtained at the near-infrared overtone of OH-stretch resonance, which provides information about the toxicity of the analyte vapor.

  11. Mass spectrometric identification of an azobenzene derivative produced by smectite-catalyzed conversion of 3-amino-4-hydroxyphenylarsonic acid

    Science.gov (United States)

    Wershaw, R. L.; Rutherford, D.W.; Rostad, C.E.; Garbarino, J.R.; Ferrer, I.; Kennedy, K.R.; Momplaisir, G.-M.; Grange, A.

    2003-01-01

    The compound 3-amino-4-hydroxyphenylarsonic acid (3-amino-HPAA) reacts with smectite to form a soluble azobenzene arsonic acid compound. This reaction is of particular interest because it provides a possible mechanism for the formation of a new type of arsenic compound in natural water systems. 3-Amino-HPAA is a degradation product excreted by chickens that are fed rations amended with roxarsone. Roxarsone is used to control coccidial intestinal parasites in most of the broiler chickens grown in the United States. The structure of the azobenzene arsonic acid compound was first inferred from negative-ion and positive-ion low-resolution mass-spectrometric analyses of the supernatant of the smectite suspension. Elemental composition of the parent ion determined by high-resolution positive-ion mass spectrometric measurements was consistent with the proposed structure of the azobenzene arsonic acid compound. Published by Elsevier Science B.V.

  12. Absorption, metabolism and effect of compatibility on absorption of qishenyiqi dropping pill.

    Science.gov (United States)

    Han, Yan-Qi; Wang, Jing; Cui, Qing-Xin; Wang, Li-Qiang; Cheng, Bin-Feng; Zhao, Hong-Zhi; Jiang, Min; Bai, Gang; Luo, Guo-An

    2014-04-01

    Qishenyiqi dropping pill (QSYQ), is a traditional Chinese medicine (TCM) prescription for treating heart diseases in China. Knowledge concerning the systemic identification of active compounds and metabolic components of QSYQ is generally lacking. Therefore, it is essential to develop a valid method for the analysis of active compounds of the combined prescription and determination of interactions among the herbs. The absorbable compounds and metabolites of QSYQ were profiled using computational chemistry prediction, an improved everted gut sac in vitro experiment, the Caco-2 cell monolayer in vitro test, a rat in vivo experiment and ultra-performance liquid chromatography/diode array detection/quadrupole-time of flight mass spectrum (UPLC/DAD/Q-TOF MS). In total, 42 prototype compounds were recognized as absorbable compounds, and eight metabolites were identified by UPLC/DAD/Q-TOF MS. The absorption rates of phenolic acids and saponins were significantly improved and the absorption of isoflavone was inhibited after compatibility. The volatile oil component had an improved effect on the absorption of other compounds, while its own absorption was inhibited. In conclusion, the present study established a rapid and effective strategy for demonstrating the absorption and metabolism of QSYQ and revealing the compatible relationship among herbs. This investigation can provide a reference for the compatibility of prescriptions and the modernization of TCM.

  13. Quantum Entanglement Molecular Absorption Spectrum Simulator

    Science.gov (United States)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

    Quantum Entanglement Molecular Absorption Spectrum Simulator (QE-MASS) is a computer program for simulating two photon molecular-absorption spectroscopy using quantum-entangled photons. More specifically, QE-MASS simulates the molecular absorption of two quantum-entangled photons generated by the spontaneous parametric down-conversion (SPDC) of a fixed-frequency photon from a laser. The two-photon absorption process is modeled via a combination of rovibrational and electronic single-photon transitions, using a wave-function formalism. A two-photon absorption cross section as a function of the entanglement delay time between the two photons is computed, then subjected to a fast Fourier transform to produce an energy spectrum. The program then detects peaks in the Fourier spectrum and displays the energy levels of very short-lived intermediate quantum states (or virtual states) of the molecule. Such virtual states were only previously accessible using ultra-fast (femtosecond) laser systems. However, with the use of a single-frequency continuous wave laser to produce SPDC photons, and QEMASS program, these short-lived molecular states can now be studied using much simpler laser systems. QE-MASS can also show the dependence of the Fourier spectrum on the tuning range of the entanglement time of any externally introduced optical-path delay time. QE-MASS can be extended to any molecule for which an appropriate spectroscopic database is available. It is a means of performing an a priori parametric analysis of entangled photon spectroscopy for development and implementation of emerging quantum-spectroscopic sensing techniques. QE-MASS is currently implemented using the Mathcad software package.

  14. Seven broad absorption line quasars with excess broad band absorption near 2250

    CERN Document Server

    Zhang, Shaohua; Jiang, Peng; Zhou, Hongyan; Ma, Jingzhe; Brandt, W N; York, Donald G; Noterdaeme, P; Schneider, Donald P

    2014-01-01

    We report the discovery of excess broad band absorption near 2250 A (EBBA) in the spectra of seven broad absorption line (BAL) quasars. By comparing with the statistical results from the control quasar sample, the significance for the detections are all above the > 4{\\sigma} level, with five above > 5{\\sigma}. The detections have also been verified by several other independent methods. The EBBAs present broader and weaker bumps at smaller wavenumbers than the Milky Way, and similar to the Large Magellanic Cloud. The EBBA bump may be related to the 2175 A bump seen in the Local Group and may be a counterpart of the 2175 A bump under different conditions in the early Universe. Furthermore, five objects in this sample show low-ionization broad absorption lines (LoBALs), such as Mg II and Al III, in addition to the high-ionization broad absorption lines (HiBALs) of C IV and Si IV. The fraction of LoBALs in our sample, ~70%, is surprisingly high compared to that of general BAL quasars, ~10%. Although the origin of...

  15. Simple field-based automated dispersive liquid-liquid microextraction of trace level phthalate esters in natural waters with gas chromatography and mass spectrometric analysis.

    Science.gov (United States)

    Leng, Geng; Chen, Wenjin; Wang, Yong

    2016-09-01

    A small, simple, and field-based automated dispersive liquid-liquid microextraction method followed by gas chromatography mass spectrometric analysis was developed for trace level phthalate esters analysis in natural waters. With a single syringe pump that is coupled with a multiposition valve, the whole extraction procedure including cleaning, sampling, mixing of extractant and disperser solvents, extraction, phase separation, and analytes collection was carried out in a totally automated way with a sample throughput of 21 h(-1) . Key factors, such as type and ratio of the extractant and disperser solvent, aspiration flow rate, extraction time, and matrix effect, were thoroughly investigated. Under the optimum conditions, linearity was found in the range from 0.03 to 60 μg/L. Limits of detection ranged from 0.0015 to 0.003 μg/L. Enrichment factors were in a range of 106-141. Reproducibility and recoveries were assessed by testing a series of three natural water samples that were spiked with different concentration levels. Finally, the proposed method was successfully applied in analysis of real surface waters. The developed system is inexpensive, light (2.6 kg), simple to use, applicable in the field, with high sample throughput, and sensitive enough for trace level phthalate esters analysis in natural waters.

  16. Automated multi-plug filtration cleanup for liquid chromatographic-tandem mass spectrometric pesticide multi-residue analysis in representative crop commodities.

    Science.gov (United States)

    Qin, Yuhong; Zhang, Jingru; Zhang, Yuan; Li, Fangbing; Han, Yongtao; Zou, Nan; Xu, Haowei; Qian, Meiyuan; Pan, Canping

    2016-09-01

    An automated multi-plug filtration cleanup (m-PFC) method on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. The automatic device was aimed to reduce labor-consuming manual operation workload in the cleanup steps. It could control the volume and the speed of pulling and pushing cycles accurately. In this work, m-PFC was based on multi-walled carbon nanotubes (MWCNTs) mixed with other sorbents and anhydrous magnesium sulfate (MgSO4) in a packed tip for analysis of pesticide multi-residues in crop commodities followed by liquid chromatography with tandem mass spectrometric (LC-MS/MS) detection. It was validated by analyzing 25 pesticides in six representative matrices spiked at two concentration levels of 10 and 100μg/kg. Salts, sorbents, m-PFC procedure, automated pulling and pushing volume, automated pulling speed, and pushing speed for each matrix were optimized. After optimization, two general automated m-PFC methods were introduced to relatively simple (apple, citrus fruit, peanut) and relatively complex (spinach, leek, green tea) matrices. Spike recoveries were within 83 and 108% and 1-14% RSD for most analytes in the tested matrices. Matrix-matched calibrations were performed with the coefficients of determination >0.997 between concentration levels of 10 and 1000μg/kg. The developed method was successfully applied to the determination of pesticide residues in market samples.

  17. Parallel development of chromatographic and mass-spectrometric methods for quantitative analysis of glycation on an IgG1 monoclonal antibody.

    Science.gov (United States)

    Viski, Kornél; Gengeliczki, Zsolt; Lenkey, Krisztián; Baranyáné Ganzler, Katalin

    2016-10-01

    Monitoring post-translational modifications (PTMs) in biotherapeutics is of paramount importance. In pharmaceutical industry, chromatography with optical detection is the standard choice of quantitation of product related impurities; and mass spectrometry is used only for characterization. Parallel development of a boronate affinity chromatographic (BAC) and a mass spectrometric methods for quantitative measurement of glycation on a monoclonal antibody (mAb) shed light on the importance of certain characteristics of the individual methods. Non-specific interactions in BAC has to be suppressed with the so-called shielding reagent. We have found that excessive amount of shielding reagents in the chromatographic solvents may cause significant underestimation of glycation. Although contamination of the retained peak with the non-glycated isoforms in BAC is unavoidable, our work shows that it can be characterized and quantitated by mass spectrometry. It has been demonstrated that glycation can be measured by mass spectrometry at the intact protein level with an LOQ value of 3.0% and error bar of ±0.5%. The BAC and MS methods have been found to provide equivalent results. These methods have not been compared from these points of view before.

  18. A liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric method for the determination of organosulfur compounds in petroleum asphalt cements.

    Science.gov (United States)

    da Silveira, Géssica Domingos; Faccin, Henrique; Claussen, Luis; Goularte, Rayane Bueno; Do Nascimento, Paulo C; Bohrer, Denise; Cravo, Margareth; Leite, Leni F M; de Carvalho, Leandro Machado

    2016-07-29

    We present a sensitive liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric (UHPLC-APPI-MS/MS) method for the determination of selected organosulfur compounds in Brazilian asphalt cements. It was possible to detect 14 organosulfur compounds of different classes where sulfoxides and sulfones presented higher sensibility in ionization than thiophenes and aromatic sulfides. A dopant-assisted APPI method was also tested, however, when chromatographic flow rate was optimized a decrease in signal was observed for all compounds. PAHs were tested and ruled out as possible interfering compounds and the matrix effect of asphalt cements was within an acceptable range for the quantification of organosulfur compounds. The proposed method was found to have satisfactory linearity and accuracy with recoveries between 83.85 and 110.28% for thianaphthene and 3-methylbenzothiophene, respectively. Therefore, the method allowed the characterization of organosulfur compounds in Brazilian asphalt cements and demonstrated changes in the amount quantified in asphaltenic and maltenic fractions after the RTFOT+SUNTEST aging process.

  19. [Health state evaluation of power-shift steering transmission using PCA-AHP methodology based on spectrometric oil analysis].

    Science.gov (United States)

    Zhang, Ying-Feng; Ma, Biao; Zheng, Chang-Song; Zhang, Jin-Le; Fan, Yu-Heng

    2010-04-01

    Spectrometric oil analysis is an important method to study the running state of power-shift steering transmission (PSST). An evaluation model of PSST health state was developed on the basis of the theories of principal component analysis (PCA) and analytic hierarchy process (AHP) using spectrometric oil analysis data. Considering the concept of mechanical equipment and wear elements in spectrometric oil analysis data, the health value was employed to quantitatively describe the running state degree of PSST, and the grades of health state were classified based on the health values. The oil analysis data were studied during the process of choosing principal components. The weight vectors of principal components were obtained by using the AHP method. In the course, the conformation of judgement matrix and the consistency check were also studied. The evaluation model was developed by combining the PCA and AHP methods. This model has been proved to have better accuracy in evaluating the running state of PSST. This work is important for developing state evaluation of PSST.

  20. Relationships between ground and airborne gamma-ray spectrometric survey data, North Ras Millan, Southern Sinai Peninsula, Egypt.

    Science.gov (United States)

    Youssef, Mohamed A S

    2016-02-01

    In the last decades of years, there was considerable growth in the use of airborne gamma-ray spectrometry. With this growth, there was an increasing need to standardize airborne measurements, so that they can be independent of survey parameters. Acceptable procedures were developed for converting airborne to ground gamma-ray spectrometric measurements of total-count intensity as well as, potassium, equivalent uranium and equivalent thorium concentrations, due to natural sources of radiation. The present study aims mainly to establish relationships between ground and airborne gamma-ray spectrometric data, North Ras Millan, Southern Sinai Peninsula, Egypt. The relationships between airborne and ground gamma-ray spectrometric data were deduced for the original and separated rock units in the study area. Various rocks in the study area, represented by Quaternary Wadi sediments, Cambro-Ordovician sandstones, basic dykes and granites, are shown on the detailed geologic map. The structures are displayed, which located on the detailed geologic map, are compiled from the integration of previous geophysical and surface geological studies.